Building Self Learning Recommendation system – VIII : Evaluating deployment options

This is the eighth and last post of our series on building a self learning recommendation system using reinforcement learning. This series consists of 8 posts where in we progressively build a self learning recommendation system.

  1. Recommendation system and reinforcement learning primer
  2. Introduction to multi armed bandit problem
  3. Self learning recommendation system as a K-armed bandit
  4. Build the prototype of the self learning recommendation system : Part I
  5. Build the prototype of the self learning recommendation system : Part II
  6. Productionising the self learning recommendation system : Part I – Customer Segmentation
  7. Productionising self learning recommendation system: Part II : Implementing self learning recommendations
  8. Evaluating deployment options for the self learning recommendation systems. ( This post )

This post ties together all what we discussed in the previous two posts where in we explored all the classes and methods we built for the application. In this post we will implement the driver file which controls all the processes and then explore different options to deploy this application.

Implementing the driver file

Now that we have seen all the classes and methods of the application, let us now see the main driver file which will control the whole process.

Open a new file and name it rlRecoMain.py and copy the following code into the file

import argparse
import pandas as pd
from utils import Conf,helperFunctions
from Data import DataProcessor
from processes import rfmMaker,rlLearn,rlRecomend
import os.path
from pymongo import MongoClient

# Construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument('-c','--conf',required=True,help='Path to the configuration file')
args = vars(ap.parse_args())

# Load the configuration file
conf = Conf(args['conf'])

print("[INFO] loading the raw files")
dl = DataProcessor(conf)

# Check if custDetails already exists. If not create it
if os.path.exists(conf["custDetails"]):
    print("[INFO] Loading customer details from pickle file")
    # Load the data from the pickle file
    custDetails = helperFunctions.load_files(conf["custDetails"])
else:
    print("[INFO] Creating customer details from csv file")
    # Let us load the customer Details
    custDetails = dl.gvCreator()
    # Starting the RFM segmentation process
    rfm = rfmMaker(custDetails,conf)
    custDetails = rfm.segmenter()
    # Save the custDetails file as a pickle file 
    helperFunctions.save_clean_data(custDetails,conf["custDetails"])

# Starting the self learning Recommendation system

# Check if the collections exist in Mongo DB
client = MongoClient(port=27017)
db = client.rlRecomendation

# Get all the collections from MongoDB
countCol = db["rlQuantdic"]
polCol = db["rlValuedic"]
rewCol = db["rlRewarddic"]
recoCountCol = db['rlRecotrack']

print(countCol.estimated_document_count())

# If Collections do not exist then create the collections in MongoDB
if countCol.estimated_document_count() == 0:
    print("[INFO] Main dictionaries empty")
    rll = rlLearn(custDetails, conf)
    # Consolidate all the products
    rll.prodConsolidator()
    print("[INFO] completed the product consolidation phase")
    # Get all the collections from MongoDB
    countCol = db["rlQuantdic"]
    polCol = db["rlValuedic"]
    rewCol = db["rlRewarddic"]

# start the recommendation phase
rlr = rlRecomend(custDetails,conf)
# Sample a state since the state is not available
stateId = rlr.stateSample()
print(stateId)

# Get the respective dictionaries from the collections

countDic = countCol.find_one({stateId: {'$exists': True}})
polDic = polCol.find_one({stateId: {'$exists': True}})
rewDic = rewCol.find_one({stateId: {'$exists': True}})

# The count dictionaries can exist but still recommendation dictionary can not exist. So we need to take this seperately

if recoCountCol.estimated_document_count() == 0:
    print("[INFO] Recommendation tracking dictionary empty")
    recoCountdic = {}
else:
    # Get the dictionary from the collection
    recoCountdic = recoCountCol.find_one({stateId: {'$exists': True}})


print('recommendation count dic', recoCountdic)


# Initialise the Collection checker method
rlr.collfinder(stateId,countDic,polDic,rewDic,recoCountdic)
# Get the list of recommended products
seg_products = rlr.rlRecommender()
print(seg_products)
# Initiate customer actions

click_list,buy_list = rlr.custAction(seg_products)
print('click_list',click_list)
print('buy_list',buy_list)

# Get the reward functions for the customer action
rlr.rewardUpdater(seg_products,buy_list ,click_list)

We import all the necessary libraries and classes in lines 1-7.

Lines 10-12, detail the argument parser process. We provide the path to our configuration file as the argument. We discussed in detail about the configuration file in post 6 of this series. Once the path of the configuration file is passed as the argument, we read the configuration file and the load the value in the variable conf in line 15.

The first of the processes is to initialise the dataProcessor class in line 18. As you know from post 6, this class has the methods for loading and processing data. After this step, lines 21-33 implements the raw data loading and processing steps.

In line 21 we check if the processed data frame custDetails is already present in the output directory. If it is present we load it from the folder in line 24. If we havent created the custDetails data frame before, we initiate that action in line 28 using the gvCreator method we have seen earlier. In lines 30-31, we create the segments for the data using the segmenter method in the rfmMaker class. Finally the custDetails data frame is saved as a pickle file in line 33.

Once the segmentation process is complete the next step is to start the recommendation process. We first establish the connection with our collection in lines 38-39. Then we collect the 4 collections from MongoDB in lines 42-45. If the collections do not exist it will return a ‘None’.

If the collections are none, we need to create the collections. This is done in lines 50-59. We instantiate the rlLearn class in line 52 and the execute the prodConsolidator() method in line 54. Once this method is run the collections would be created. Please refer to the prodConsolidator() method in post 7 for details. Once the collections are created, we get those collections in lines 57-59.

Next we instantiate the rlRecomend class in line 62 and then sample a stateID in line 64. Please note that the sampling of state ID is only a work around to simulate a state in the absence of real customer data. If we were to have a live application, then the state Id would be created each time a customer logs into the sytem to buy products. As you know the state Id is a combination of the customers segment, month and day in which the logging happens. So as there are no live customers we are simulating the stateId for our online recommendation process.

Once we have sampled the stateId, we need to extract the dictionaries corresponding to that stateId from the MongoDb collections. We do that in lines 69-71. We extract the dictionary corresponding to the recommendation as a seperate step in lines 75-80.

Once all the dictionaries are extracted, we do the initialisation of the dictionaries in line 87 using the collfinder method we explored in post 7 . Once the dictionaries are initialised we initiate the recommendation process in line 89 to get the list of recommended products.

Once we get the recommended products we simulate customer actions in line 93, and then finally update the rewards and values using rewardUpdater method in line 98.

This takes us to the end of the complete process to build the online recommendation process. Let us now see how this application can be run on the terminal

Figure 1 : Running the application on terminal

The application can be executed on the terminal with the below command

$ python rlRecoMain.py --conf config/custprof.json

The argument we give is the path to the configuration file. Please note that we need to change directory to the rlreco directory to run this code. The output from the implementation would be as below

The data can be seen in the MongoDB collections also. Let us look at ways to find the data in MongoDB collections.

To initialise Mongo db from terminal, use the following command

Figure 3 : Initialize Mongo

You should get the following output

Now to find all the data bases in Mongo DB you can use the below command

You will be able to see all the databases which you have created. The one marked in red is the database we created. No to use that data base the command used is use rlRecomendation as shown below. We will get the command that the database has been switched to the desired data base.

To see all the collections we have made in this database we can use the below command.

From the output we can see all the collections we have created. Now to see some specific record within the collections, we can use the following command.

db.rlValuedic.find({"Q1_August_1_Monday":{$exists:true} })

In the above command we are trying to find all records in the collection rlValuedic for the stateID "Q1_August_1_Monday". Once we execute this command we get all the records in this collection for this specific stateID. You should get the below output.

The output displays all the proucts for that stateID and its value function.

What we have implemented in code is a simulation of the complete process. To run this continuously for multiple customers, we can create another scrip with a list of desired customers and then execute the code multiple times. I will leave that step as an exercise for you to implement. Now let us look at different options to deploy this application.

Deployment of application

The end product of any data science endeavour should be to build an application and sharing it with the world. There are different options to deploy python applications. Let us look at some of the options available. I would encourage you to explore more methods and share your results.

Flask application with Heroku

A great option to deploy your applications is to package it as a Flask application and then deploy it using Heroku. We have discussed this option in one of our earlier series, where we built a machine translation application. You can refer this link for details. In this section we will discuss the nuances of building the application in Flask and then deploying it on Heroku. I will leave the implementation of the steps for you as an exercise.

When deploying the self learning recommendation system we have built, the first thing which we need to design is what the front end will contain. From the perspective of the processes we have implemented, we need to have the following processes controlled using the front end.

  1. Training process : This is the process which takes the raw data, preprocesses the data and then initialises all the dictionaries. This includes all the processes till line 59 in the driver file rlRecoMain.py. We need to initialise the process of training from the front end of the flask application. In the background all the process till line 59 should run and the dictionaries needs to be updated.
  2. Recommendation simulation : The second process which needs to be controlled is the one where we get the recommendations. The start of this process is the simulation of the state from the front end. To do this we can provide a drop down of all the customer IDs on the flask front end and take the system time details to form the stateID. Once this stateID is generated, we start the recommendation process which includes all the process starting from line 62 till line 90 in the the driver file rlRecoMain.py. Please note that line 64 is the stateID simulating process which will be controlled from the front end. So that line need not be implemented. The final output, which is the list of all recommended products needs to be displayed on the front end. It will be good to add some visual images along with the product for visual impact.
  3. Customer action simulation : Once the recommended products are displayed on the front end, we can send feed back from the front end in terms of the products clicked and the products bought through some widgets created in the front end. These widgets will take the place of line 93, in our implementation. These feed back from the front end needs to be collected as lists, which will take the place of click_list and buy_list given in lines 94-95. Once the customer actions are generated, the back end process in line 98, will have to kick in to update the dictionaries. Once the cycle is completed we can build a refresh button on the screen to simulate the recommendation process again.

Once these processes are implemented using a Flask application, the application can be deployed on Heroku. This post will give you overall guide into deploying the application on Heroku.

These are broad guidelines for building the application and then deploying them. These need not be the most efficient and effective ones. I would challenge each one of you to implement much better processes for deployment. Request you to share your implementations in the comments section below.

Other options for deployment

So far we have seen one of the option to build the application using Flask and then deploy them using Heroku. There are other options too for deployment. Some of the noteable ones are the following

  • Flask application on Ubuntu server
  • Flask application on Docker

The attached link is a great resource to learn about such deployment. I would challenge all of you to deploy using any of these implementation steps and share the implementation for the community to benefit.

Wrapping up.

This is the last post of the series and we hope that this series was informative.

We will start a new series in the near future. The next series will be on a specific problem on computer vision specifically on Object detection. In the next series we will be building a ‘Road pothole detector using different object detection algorithms. This series will touch upon different methods in object detection like Image Pyramids, RCNN, Yolo, Tensorflow Object detection API etc. Watch out this space for the next series.

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You can also subscribe to our Youtube channel for all the videos related to this series.

The complete code base for the series is in the Bayesian Quest Git hub repository

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I would also recommend two books I have co-authored. The first one is specialised in deep learning with practical hands on exercises and interactive video and audio aids for learning

This book is accessible using the following links

The Deep Learning Workshop on Amazon

The Deep Learning Workshop on Packt

The second book equips you with practical machine learning skill sets. The pedagogy is through practical interactive exercises and activities.

The Data Science Workshop Book

This book can be accessed using the following links

The Data Science Workshop on Amazon

The Data Science Workshop on Packt

Enjoy your learning experience and be empowered !!!!

Building Self Learning Recommendation system – VII : Productionizing the application : II

This is the seventh post of our series on building a self learning recommendation system using reinforcement learning. This series consists of 8 posts where in we progressively build a self learning recommendation system.

  1. Recommendation system and reinforcement learning primer
  2. Introduction to multi armed bandit problem
  3. Self learning recommendation system as a K-armed bandit
  4. Build the prototype of the self learning recommendation system : Part I
  5. Build the prototype of the self learning recommendation system : Part II
  6. Productionising the self learning recommendation system : Part I – Customer Segmentation
  7. Productionising the self learning recommendation system: Part II – Implementing self learning recommendation ( This Post )
  8. Evaluating different deployment options for the self learning recommendation systems.

This post builds on the previous post where we started off with productionizing the application using python scripts. In the last post we completed the customer segmentation part. In this post we continue from where we left off and then build the self learning system using python scripts. Let us get going.

Creation of States

Let us take a quick recap of the project structure and what we covered in the last post.

In the last post we were in the early part of our main driver file rlRecoMain.py. We explored rfmMaker class in file rfmProcess.py from the processes directory. We will now explore selfLearnProcess.py file in the same directory.

Open a new file and name it selfLearnProcess.py and insert the following code

import pandas as pd
from numpy.random import normal as GaussianDistribution
from collections import OrderedDict
from collections import Counter
import operator
from random import sample
import numpy as np
from pymongo import MongoClient
client = MongoClient(port=27017)
db = client.rlRecomendation



class rlLearn:
    def __init__(self,custDetails,conf):
        # Get the date  as a seperate column
        custDetails['Date'] = custDetails['Parse_date'].apply(lambda x: x.strftime("%d"))
        # Converting date to float for easy comparison
        custDetails['Date'] = custDetails['Date'].astype('float64')
        # Get the period of month column
        custDetails['monthPeriod'] = custDetails['Date'].apply(lambda x: int(x > conf['monthPer']))
        # Aggregate the custDetails to get a distribution of rewards
        rewardFull = custDetails.groupby(['Segment', 'Month', 'monthPeriod', 'Day', conf['product_id']])[conf['prod_qnty']].agg(
            'sum').reset_index()
        # Get these data frames for all methods
        self.custDetails = custDetails
        self.conf = conf
        self.rewardFull = rewardFull
        # Defining some dictionaries for storing the values
        self.countDic = {}  # Dictionary to store the count of products
        self.polDic = {}  # Dictionary to store the value distribution
        self.rewDic = {}  # Dictionary to store the reward distribution
        self.recoCountdic = {}  # Dictionary to store the recommendation counts

    # Method to find unique values of each of the variables
    def uniqeVars(self):
        # Finding unique value for each of the variables
        segments = list(self.rewardFull.Segment.unique())
        months = list(self.rewardFull.Month.unique())
        monthPeriod = list(self.rewardFull.monthPeriod.unique())
        days = list(self.rewardFull.Day.unique())
        return segments,months,monthPeriod,days

    # Method to consolidate all products
    def prodConsolidator(self):
        # Get all the unique values of the variables
        segments, months, monthPeriod, days = self.uniqeVars()
        # Creating the consolidated dictionary
        for seg in segments:
            for mon in months:
                for period in monthPeriod:
                    for day in days:
                        # Get the subset of the data
                        subset1 = self.rewardFull[(self.rewardFull['Segment'] == seg) & (self.rewardFull['Month'] == mon) & (
                                self.rewardFull['monthPeriod'] == period) & (self.rewardFull['Day'] == day)]
                        # INitializing a temporary dictionary to storing in mongodb
                        tempDic = {}
                        # Check if the subset is valid
                        if len(subset1) > 0:
                            # Iterate through each of the subset and get the products and its quantities
                            stateId = str(seg) + '_' + mon + '_' + str(period) + '_' + day
                            # Define a dictionary for the state ID
                            self.countDic[stateId] = {}
                            tempDic[stateId] = {}
                            for i in range(len(subset1.StockCode)):
                                # Store in the Count dictionary
                                self.countDic[stateId][subset1.iloc[i]['StockCode']] = int(subset1.iloc[i]['Quantity'])
                                tempDic[stateId][subset1.iloc[i]['StockCode']] = int(subset1.iloc[i]['Quantity'])
                            # Dumping each record into mongo db
                            db.rlQuantdic.insert(tempDic)

        # Consolidate the rewards and value functions based on the quantities
        for key in self.countDic.keys():
            # Creating two temporary dictionaries for loading in Mongodb
            tempDicpol = {}
            tempDicrew = {}
            # First get the dictionary of products for a state
            prodCounts = self.countDic[key]
            self.polDic[key] = {}
            self.rewDic[key] = {}
            # Initializing temporary dictionaries also
            tempDicpol[key] = {}
            tempDicrew[key] = {}
            # Update the policy values
            for pkey in prodCounts.keys():
                # Creating the value dictionary using a Gaussian process
                self.polDic[key][pkey] = GaussianDistribution(loc=prodCounts[pkey], scale=1, size=1)[0].round(2)
                tempDicpol[key][pkey] = self.polDic[key][pkey]
                # Creating a reward dictionary using a Gaussian process
                self.rewDic[key][pkey] = GaussianDistribution(loc=prodCounts[pkey], scale=1, size=1)[0].round(2)
                tempDicrew[key][pkey] = self.rewDic[key][pkey]
            # Dumping each of these in mongo db
            db.rlRewarddic.insert(tempDicrew)
            db.rlValuedic.insert(tempDicpol)
        print('[INFO] Dumped the quantity dictionary,policy and rewards in MongoDB')

As usual we start with import of the libraries we want from lines 1-7. In this implementation we make a small deviation from the prototype which we developed in the previous post. During the prototyping phase we predominantly relied on dictionaries to store data. However here we would be storing data in Mongo DB. Those of you who are not fully conversant with MongoDB can refer to some good tutorials on MongDB like the one here. I will also be explaining the key features as and when required. In line 8, we import the MongoClient which is required for connections with the data base. We then define the client using the default port number ( 27017 ) in line 9 and then name the data base where we will store the recommendation in line 10. The name of the database we have selected is rlRecomendation . You are free to choose any name of your choice.

Let us now explore the rlLearn class. The constructor of the class which starts from line 15, takes the custDetails data frame and the configuration file as inputs. You would already be familiar with lines 17-23 from our prototyping phase, where we extract information to create states and then consolidate the data frame to get the quantities of each state. In lines 30-33, we create dictionaries where we store the relevant information like count of products, value distribution, reward distribution and the number of times the products are recommended.

The main method within the rlLearn class is the prodConslidator() method in lines 45-95. We have seen the details of this method in the prototyping phase. Just to recap, in this method we iterate through each of the components of our states and then store the quantities of each product under the state in the dictionaries. However there is a subtle difference from what we did during the prototyping phase. Here we are inserting each state and its associated products in Mongodb data base we created, as shown in line 70, 93 and 94. We create a temporary dictionary in line 57 to dump each state into Mongodb. We also store the data in the dictionaries,as we did during the prototyping phase, so that we get the data for other methods in this class. The final outcome from this method, is the creation of the count dictionary, value dictionary and reward dictionary from our data and updation of this data in Mongodb.

This takes us to the end of the rlLearn class.

We now go back to the driver file rlRecoMain.py and the explore the next important class rlRecomend.

The rlRecomend class has the methods which are required for recommending products. This class has many methods and therefore we will go one by one through each of the methods. We have seen all these methods during the prototyping phase and therefore we will not get into detailed explanation of these methods here. For detailed explanation you can refer to the previous post.

Now on the selfLearnProcess.py start adding the code pertaining to the rlRecomend class.

class rlRecomend:
    def __init__(self, custDetails, conf):
        # Get the date  as a seperate column
        custDetails['Date'] = custDetails['Parse_date'].apply(lambda x: x.strftime("%d"))
        # Converting date to float for easy comparison
        custDetails['Date'] = custDetails['Date'].astype('float64')
        # Get the period of month column
        custDetails['monthPeriod'] = custDetails['Date'].apply(lambda x: int(x > conf['monthPer']))
        # Aggregate the custDetails to get a distribution of rewards
        rewardFull = custDetails.groupby(['Segment', 'Month', 'monthPeriod', 'Day', conf['product_id']])[
            conf['prod_qnty']].agg(
            'sum').reset_index()
        # Get these data frames for all methods
        self.custDetails = custDetails
        self.conf = conf
        self.rewardFull = rewardFull

The above code is for the constructor of the class ( lines 97 – 112 ), which is similar to the constructor of the rlLearn class. Here we consolidate the custDetails data frame and get the count of each products for the respective state.

Let us now look at the next two methods. Add the following code to the class we earlier created.

# Method to find unique values of each of the variables
    def uniqeVars(self):
        # Finding unique value for each of the variables
        segments = list(self.rewardFull.Segment.unique())
        months = list(self.rewardFull.Month.unique())
        monthPeriod = list(self.rewardFull.monthPeriod.unique())
        days = list(self.rewardFull.Day.unique())
        return segments, months, monthPeriod, days

    # Method to sample a state
    def stateSample(self):
        # Get the unique state elements
        segments, months, monthPeriod, days = self.uniqeVars()
        # Get the context of the customer. For the time being let us randomly select all the states
        seg = sample(segments, 1)[0]  # Sample the segment
        mon = sample(months, 1)[0]  # Sample the month
        monthPer = sample([0, 1], 1)[0]  # sample the month period
        day = sample(days, 1)[0]  # Sample the day
        # Get the state id by combining all these samples
        stateId = str(seg) + '_' + mon + '_' + str(monthPer) + '_' + day
        self.seg = seg
        return stateId

The first method , lines 115 – 121, is to get the unique values of segments, months, month-period and days. This information will be used in some of the methods we will see later on. The second method detailed in lines 124-135, is to sample a state id, through random sampling of the components of a state.

The next methods we will explore are to initialise dictionaries if a state id has not been seen earlier. The first method initialises dictionaries and the second method inserts a recommendation collection record in MongoDB if the state dosent exist. Let us see the code for these methods.

  # Method to initialize a dictionary in case a state Id is not available
    def collfinder(self,stateId,countDic,polDic,rewDic,recoCountdic):
        # Defining some dictionaries for storing the values
        self.countDic = countDic  # Dictionary to store the count of products
        self.polDic = polDic  # Dictionary to store the value distribution
        self.rewDic = rewDic  # Dictionary to store the reward distribution
        self.recoCountdic = recoCountdic  # Dictionary to store the recommendatio
        self.stateId = stateId
        print("[INFO] The current state is :", stateId)
        if self.countDic is None:
            print("[INFO] State ID do not exist")
            self.countDic = {}
            self.countDic[stateId] = {}
            self.polDic = {}
            self.polDic[stateId] = {}
            self.rewDic = {}
            self.rewDic[stateId] = {}
        if self.recoCountdic is None:
            self.recoCountdic = {}
            self.recoCountdic[stateId] = {}
        else:
            self.recoCountdic[stateId] = {}

# Method to update the recommendation dictionary
    def recoCollChecker(self):
        print("[INFO] Inside the recommendation collection")
        recoCol = db.rlRecotrack.find_one({self.stateId: {'$exists': True}})
        if recoCol is None:
            print("[INFO] Inserting the record in the recommendation collection")
            db.rlRecotrack.insert_one({self.stateId: {}})
        return recoCol

The inputs to the first method, as in line 138 are the state Id and all the other 4 dictionaries we extract from Mongo DB, which we will see later on in the main script rlRecoMain.py. If no record exists for a specific state Id, the dictionaries we extract from Mongo DB would be null and therefore we need to initialize these dictionaries for storing all the values of products, its values, rewards and the count of recommendations. The initialisation of these dictionaries are implemented in this method from lines 146-158.

The second initialisation method is to check for the recommendation count dictionary for a specific state Id. We first check for the state Id in the collection in line 163. If the record dosent exist then we insert a blank dictionary for that state in line 166.

Let us now look at the next two methods in the class

    # Create a function to get a list of products for a certain segment
    def segProduct(self,seg, nproducts):
        # Get the list of unique products for each segment
        seg_products = list(self.rewardFull[self.rewardFull['Segment'] == seg]['StockCode'].unique())
        seg_products = sample(seg_products, nproducts)
        return seg_products

    # This is the function to get the top n products based on value
    def sortlist(self,nproducts,seg):
        # Get the top products based on the values and sort them from product with largest value to least
        topProducts = sorted(self.polDic[self.stateId].keys(), key=lambda kv: self.polDic[self.stateId][kv])[-nproducts:][::-1]
        # If the topProducts is less than the required number of products nproducts, sample the delta
        while len(topProducts) < nproducts:
            print("[INFO] top products less than required number of products")
            segProducts = self.segProduct(seg, (nproducts - len(topProducts)))
            newList = topProducts + segProducts
            # Finding unique products
            topProducts = list(OrderedDict.fromkeys(newList))
        return topProducts

The method in lines 171-175 is to sample a list of products for a segment. This method is used incase the number of products in a particular state is less than the total number of products which we want to recommend. In such cases, we randomly sample some products from the list of all products bought by customers in that segment and then add it to the list of products we want to recommend. We will see this in action in sortlist method (lines 178-188).

The sortlist method, sorts the list of products based on the demand for that product and the returns the list of top products. The inputs to this method are the number of products we want to be recommended and the segment ( line 178 ). We then get the top ‘n‘ products by sorting the value dictionary based on the number of times a product is bought as in line 180. If the number of products is less than the required products, sampling of products is done using the segProduct method we saw earlier. The final list of top products is then returned by this method.

The next method which we are going to explore is the one which controls the exploration and exploitation process thereby generating a list of products to be recommended. Let us add the following code to the class.

# This is the function to create the number of products based on exploration and exploitation
    def sampProduct(self,seg, nproducts,epsilon):
        # Initialise an empty list for storing the recommended products
        seg_products = []
        # Get the list of unique products for each segment
        Segment_products = list(self.rewardFull[self.rewardFull['Segment'] == seg]['StockCode'].unique())
        # Get the list of top n products based on value
        topProducts = self.sortlist(nproducts,seg)
        # Start a loop to get the required number of products
        while len(seg_products) < nproducts:
            # First find a probability
            probability = np.random.rand()
            if probability >= epsilon:
                # print(topProducts)
                # The top product would be first product in the list
                prod = topProducts[0]
                # Append the selected product to the list
                seg_products.append(prod)
                # Remove the top product once appended
                topProducts.pop(0)
                # Ensure that seg_products is unique
                seg_products = list(OrderedDict.fromkeys(seg_products))
            else:
                # If the probability is less than epsilon value randomly sample one product
                prod = sample(Segment_products, 1)[0]
                seg_products.append(prod)
                # Ensure that seg_products is unique
                seg_products = list(OrderedDict.fromkeys(seg_products))
        return seg_products

The inputs to the method are the segment, number of products to be recommended and the epsilon value which determines exploration and exploitation as shown in line 191. In line 195, we get the list of the products for the segment. This list is from where products are sampled during the exploration phase. We also get the list of top products which needs to be recommended in line 197, using the sortlist method we defined earlier. In lines 199-218 we implement the exploitation and exploration processes we discussed during the prototyping phase and finally we return the list of top products for recommendation.

The next method which we will explore is the one to update dictionaries after the recommendation process.

# This is the method for updating the dictionaries after recommendation
    def dicUpdater(self,prodList, stateId):        
        for prod in prodList:
            # Check if the product is in the dictionary
            if prod in list(self.countDic[stateId].keys()):
                # Update the count by 1
                self.countDic[stateId][prod] += 1                
            else:
                self.countDic[stateId][prod] = 1                
            if prod in list(self.recoCountdic[stateId].keys()):
                # Update the recommended products with 1
                self.recoCountdic[stateId][prod] += 1                
            else:
                # Initialise the recommended products as 1
                self.recoCountdic[stateId][prod] = 1                
            if prod not in list(self.polDic[stateId].keys()):
                # Initialise the value as 0
                self.polDic[stateId][prod] = 0                
            if prod not in list(self.rewDic[stateId].keys()):
                # Initialise the reward dictionary as 0
                self.rewDic[stateId][prod] = GaussianDistribution(loc=0, scale=1, size=1)[0].round(2)                
        print("[INFO] Completed the initial dictionary updates")

The inputs to this method, as in line 221, are the list of products to be recommended and the state Id. From lines 222-234, we iterate through each of the recommended product and increament the count in the dictionary if the product exists in the dictionary or initialize the count to 1 if the product wasnt available. Later on in lines 235-240, we initialise the value dictionary and the reward dictionary if the products are not available in them.

The next method we will see is the one for initializing the dictionaries in case the context dosent exist.

    def dicAdder(self,prodList, stateId):        
        # Loop through the product list
        for prod in prodList:
            # Initialise the count as 1
            self.countDic[stateId][prod] = 1
            # Initialise the value as 0
            self.polDic[stateId][prod] = 0
            # Initialise the recommended products as 1
            self.recoCountdic[stateId][prod] = 1
            # Initialise the reward dictionary as 0
            self.rewDic[stateId][prod] = GaussianDistribution(loc=0, scale=1, size=1)[0].round(2)
        print("[INFO] Completed the dictionary initialization")
        # Next update the collections with the respective updates        
        # Updating the quantity collection
        db.rlQuantdic.insert_one({stateId: self.countDic[stateId]})
        # Updating the recommendation tracking collection
        db.rlRecotrack.insert_one({stateId: self.recoCount[stateId]})
        # Updating the value function collection for the products
        db.rlValuedic.insert_one({stateId: self.polDic[stateId]})
        # Updating the rewards collection
        db.rlRewarddic.insert_one({stateId: self.rewDic[stateId]})
        print('[INFO] Completed updating all the collections')

If the state Id dosent exist, the dictionaries are initialised as seen in lines 147-155. Once the dictionaries are initialised, MongoDb data bases are updated in lines 259-265.

The next method which we are going to explore is one of the main methods which integrates all the methods we have seen so far. This methods implements the recomendation process. Let us explore this method.

# Method to sample a stateID and then initialize the dictionaries
    def rlRecommender(self):
        # First sample a stateID
        stateId = self.stateId        
        # Start the recommendation process
        if len(self.polDic[stateId]) > 0:
            print("The context exists")
            # Implement the sampling of products based on exploration and exploitation
            seg_products = self.sampProduct(self.seg, self.conf["nProducts"],self.conf["epsilon"])
            # Check if the recommendation count collection exist
            recoCol = self.recoCollChecker()
            print('Recommendation collection existing :',recoCol)
            # Update the dictionaries of values and rewards
            self.dicUpdater(seg_products, stateId)
        else:
            print("The context dosent exist")
            # Get the list of relavant products
            seg_products = self.segProduct(self.seg, conf["nProducts"])
            # Add products to the value dictionary and rewards dictionary
            self.dicAdder(seg_products, stateId)
        print("[INFO] Completed the recommendation process")

        return seg_products

The first step in the process is to get the state Id ( line 271 ) based on which we have to do all the recommendations. Once we have the state Id, we check if it is an existing state id in line 273. If it is an existing state Id we get the list of ‘n’ products for recommendation using the sampProduct method we saw earlier, where we implement exploration and exploitation. Once we get the products we initialise the recommendation collection in line 278. Finally we update all dictionaries using the dicUpdater method in line 281.

From lines 282-287, we implement a similar process when the state Id dosent exist. The only difference in this case is in the initialisation of the dictionaries in line 287, where we use the dicAdder method.

Once we complete the recommendation process, we get into simulating the customer action.

# Function to initiate customer action
    def custAction(self,segproducts):
        print('[INFO] getting the customer action')
        # Sample a value to get how many products will be clicked
        click_number = np.random.choice(np.arange(0, 10),
                                        p=[0.50, 0.35, 0.10, 0.025, 0.015, 0.0055, 0.002, 0.00125, 0.00124, 0.00001])
        # Sample products which will be clicked based on click number
        click_list = sample(segproducts, click_number)

        # Sample for buy values
        buy_number = np.random.choice(np.arange(0, 10),
                                      p=[0.70, 0.15, 0.10, 0.025, 0.015, 0.0055, 0.002, 0.00125, 0.00124, 0.00001])
        # Sample products which will be bought based on buy number
        buy_list = sample(segproducts, buy_number)

        return click_list, buy_list

Lines 296-305 implements the processes for simulating the list of products which are bought and browsed by the customer based on the recommendation we made. The method returns the list of products which were browsed through and also the one which were bought. For detailed explanations on these methods please refer the previous post

The next methods we will explore are the ones related to the value updation of the recommendation system.

    def getReward(self,loc):
        rew = GaussianDistribution(loc=loc, scale=1, size=1)[0].round(2)
        return rew

    def saPolicy(self,rew, prod):
        # This function gets the relavant algorithm for the policy update
        # Get the current value of the state        
        vcur = self.polDic[self.stateId][prod]        
        # Get the counts of the current product
        n = self.recoCountdic[self.stateId][prod]        
        # Calculate the new value
        Incvcur = (1 / n) * (rew - vcur)       
        return Incvcur

The getReward method on line 309 is to generate a reward from a gaussian distribution centred around the reward value. We will see the use of this method in subsequent methods.

The saPolicy method in lines 313-321 updates the value of the state based on the simple averaging method in line 320. We have already seen these methods in our prototyping phase in the previous post.

Next we will see the method which uses both the above methods.

    def valueUpdater(self,seg_products, loc, custList, remove=True):
        for prod in custList:
            # Get the reward for the bought product. The reward will be centered around the defined reward for each action
            rew = self.getReward(loc)            
            # Update the reward in the reward dictionary
            self.rewDic[self.stateId][prod] += rew            
            # Update the policy based on the reward
            Incvcur = self.saPolicy(rew, prod)            
            self.polDic[self.stateId][prod] += Incvcur           
            # Remove the bought product from the product list
            if remove:
                seg_products.remove(prod)
        return seg_products

The inputs to this method are the recommended list of products, the mean reward ( click, buy or ignore), the corresponding list ( click list or buy list) and a flag to indicate if the product has to be removed from the recommendation list or not.

We interate through all the products in the customer action list in line 324 and then gets the reward in line 326. Once the reward is incremented in the reward dictionary in line 328, we get the incremental value in line 330 and this is updated in the value dictionary in line 331. If the flag is True, we remove the product from the recommended list and the finally returns the remaining recommendation list.

The next method is the last of the methods and ties the above three methods with the customer action.

# Function to update the reward dictionary and the value dictionary based on customer action
    def rewardUpdater(self, seg_products,custBuy=[], custClick=[]):
        # Check if there are any customer purchases
        if len(custBuy) > 0:
            seg_products = self.valueUpdater(seg_products, self.conf['buyReward'], custBuy)
            # Repeat the same process for customer click
        if len(custClick) > 0:
            seg_products = self.valueUpdater(seg_products, self.conf['clickReward'], custClick)
            # For those products not clicked or bought, give a penalty
        if len(seg_products) > 0:
            custList = seg_products.copy()
            seg_products = self.valueUpdater(seg_products, -2, custList,False)
        # Next update the collections with the respective updates
        print('[INFO] Updating all the collections')
        # Updating the quantity collection
        db.rlQuantdic.replace_one({self.stateId: {'$exists': True}}, {self.stateId: self.countDic[self.stateId]})
        # Updating the recommendation tracking collection
        db.rlRecotrack.replace_one({self.stateId: {'$exists': True}}, {self.stateId: self.recoCountdic[self.stateId]})
        # Updating the value function collection for the products
        db.rlValuedic.replace_one({self.stateId: {'$exists': True}}, {self.stateId: self.polDic[self.stateId]})
        # Updating the rewards collection
        db.rlRewarddic.replace_one({self.stateId: {'$exists': True}}, {self.stateId: self.rewDic[self.stateId]})
        print('[INFO] Completed updating all the collections')

In lines 340-348, we update the value based on the number of products bought, clicked and ignored. Once the value dictionaries are updated, the respective MongoDb dictionaries are updated in lines 352-358.

With this we have covered all the methods which are required for implementing the self learning recommendation system. Let us summarise our learning so far in this post.

  • Created the states and updated MongoDB with the states data. We used the historic data for initialisation of values.
  • Implemented the recommendation process by getting a list of products to be recommended to the customer
  • Explored customer response simulation wherein the customer response to the recommended products were implemented.
  • Updated the value functions and reward functions after customer response
  • Updated Mongo DB collections after the completion of the process for a customer.

What next ?

We are coming to the fag end of our series. The next post is where we tie all these methods together in the main driver file and see how these processes are implmented. We will also run the script on the terminal and observe the results. Once the application implementation is done, we will also explore avenues to deploy the application. Watch this space for the last post of the series.

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The complete code base for the series is in the Bayesian Quest Git hub repository

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The Data Science Workshop Book

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Building Self Learning Recommendation system – VI : Productionizing the application : I

This is the sixth post of our series on building a self learning recommendation system using reinforcement learning. This series consists of 8 posts where in we progressively build a self learning recommendation system. This series consists of the following posts

  1. Recommendation system and reinforcement learning primer
  2. Introduction to multi armed bandit problem
  3. Self learning recommendation system as a K-armed bandit
  4. Build the prototype of the self learning recommendation system : Part I
  5. Build the prototype of the self learning recommendation system : Part II
  6. Productionising the self learning recommendation system: Part I – Customer Segmentation ( This post )
  7. Productionising the self learning recommendation system: Part II – Implementing self learning recommendation
  8. Evaluating different deployment options for the self learning recommendation systems.

This post builds on the previous post where we started off with building the prototype of the application in Jupyter notebooks. In this post we will see how to convert our prototype into Python scripts. Converting into python script is important because that is the basis for building an application and then deploying them for general consumption.

File Structure for the project

First let us look at the file structure of our project.

The directory RL_Recomendations is the main directory which contains other folders which are required for the project. Out of the directories rlreco is a virtual environment we will create and all our working directories are within this virtual environment.Along with the folders we also have the script rlRecoMain.py which is the main driver script for the application. We will now go through some of the steps in creating this folder structure

When building an application it is always a good practice to create a virtual environment and then complete the application build process within the virtual environment. We talked about this in one of our earlier series for building machine translation applications . This way we can ensure that only application specific libraries and packages are present when we deploy our application.

Let us first create a separate folder in our drive and then create a virtual environment within that folder. In a Linux based system, a seperate folder can be created as follows

$ mkdir RL_Recomendations

Once the new directory is created let us change directory into the RL_Recomendations directory and then create a virtual environment. A virtual environment can be created on Linux with Python3 with the below script

RL_Recomendations $ python3 -m venv rlreco

Here the rlreco is the name of our virtual environment. The virtual environment which we created can be activated as below

RL_Recomendations $ source rlreco/bin/activate

Once the virtual environment is enabled we will get the following prompt.

(rlreco) ~$

In addition you will notice that a new folder created with the same name as the virtual environment. We will use that folder to create all our folders and main files required for our application. Let us traverse through our driver file and then create all the folders and files required for our application.

Create the driver file

Open a file using your favourite editor and name it rlRecoMain.py and the insert the following code.

import argparse
import pandas as pd
from utils import Conf,helperFunctions
from Data import DataProcessor
from processes import rfmMaker,rlLearn,rlRecomend
from utils import helperFunctions
import os.path
from pymongo import MongoClient

Lines 1-2 we import the libraries which we require for our application. In line 3 we have to import Conf class from the utils folder.

So first let us create a folder called utils, which will have the following file structure.

The utils folder has a file called Conf.py which contains the Conf class and another file called helperFunctions.py . The first file controls the configuration functions and the second file contains some of the helper functions like saving data into pickle files. We will get to that in a moment.

First let us open a new python file Conf.py and copy the following code.

from json_minify import json_minify
import json

class Conf:

    def __init__(self,confPath):
        # Read the json file and load it into a dictionary
        conf = json.loads(json_minify(open(confPath).read()))
        self.__dict__.update(conf)
    def __getitem__(self, k):
        return self.__dict__.get(k,None)

The Conf class is a simple class, with its constructor loading the configuration file which is in json format in line 8. Once the configuration file is loaded the elements are extracted by invoking ‘conf’ method. We will see more of how this is used later.

We have talked about the Conf class which loads the configuration file, however we havent made the configuration file yet. As you may know a configuration file contains all the parameters in the application. Let us see the directory structure of the configuration file.

Figure : config folder and configuration file

You can now create the folder called config, under the rlreco folder and then open a file in your editor and then name it custprof.json and include the following code.

{

  /****
  * paths required
  ****/

  "inputData" : "/media/acer/7DC832E057A5BDB1/JMJTL/Tomslabs/Datasets/Retail/OnlineRetail.csv",
  "custDetails" : "/media/acer/7DC832E057A5BDB1/JMJTL/Tomslabs/BayesianQuest/RL_Recomendations/rlreco/output/custDetails.pkl",

  /****
  * Column mapping
  ****/

  "order_id" : "InvoiceNo",
  "product_id": "StockCode",
  "product" : "Description",
  "prod_qnty" : "Quantity",
  "order_date" : "InvoiceDate",
  "unit_price" : "UnitPrice",
  "customer_id" : "CustomerID",
    /****
  * Parameters
  ****/

  "nclust" : 4,
  "monthPer" : 15,
  "epsilon" : 0.1,
  "nProducts" : 10,
  "buyReward" : 5,
  "clickReward": 1
}

As you can see the config, file contains all the configuration items required as part of the application. The first part is where the paths to the raw file and processed pickle files are stored. The second part is the mapping of the column names in the raw file and the names used in our application. The third part contains all the parameters required for the application. The Conf class which we earlier saw will read the json file and all these parameters will be loaded to memory for us to be used in the application.

Lets come back to the utils folder and create the second file which we will name as helperFunctions.py and insert the following code.

from pickle import load
from pickle import dump
import numpy as np


# Function to Save data to pickle form
def save_clean_data(data,filename):
    dump(data,open(filename,'wb'))
    print('Saved: %s' % filename)

# Function to load pickle data from disk
def load_files(filename):
    return load(open(filename,'rb'))

This file contains two functions. The first function starting in line 7 saves a file in pickle format to the specified path. The second function in line 12, loads a pickle file and return the data. These two functions are handy functions which will be used later in our project.

We will come back to the main file rlRecoMain.py and look at the next folder and methods on line 4. In this line we import DataProcessor method from the folder Data . Let us take a look at the folder called Data.

Create the data processor module

The class and the methods associated with the class are in the file dataLoader.py. Let us first create the folder, Data and then open a file named dataLoader.py and insert the following code.

import os
import pandas as pd
import pickle
import numpy as np
import random
from utils import helperFunctions
from datetime import datetime, timedelta,date
from dateutil.parser import parse

class DataProcessor:
    def __init__(self,configfile):
        # This is the first method in the DataProcessor class
        self.config = configfile

     # This is the method to load data from the input files
    def dataLoader(self):
        inputPath = self.config["inputData"]
        dataFrame = pd.read_csv(inputPath,encoding = "ISO-8859-1")
        return dataFrame

    # This is the method for parsing dates
    def dateParser(self):
        custDetails = self.dataLoader()
        #Parsing  the date
        custDetails['Parse_date'] = custDetails[self.config["order_date"]].apply(lambda x: parse(x))
        # Parsing the weekdaty
        custDetails['Weekday'] = custDetails['Parse_date'].apply(lambda x: x.weekday())
        # Parsing the Day
        custDetails['Day'] = custDetails['Parse_date'].apply(lambda x: x.strftime("%A"))
        # Parsing the Month
        custDetails['Month'] = custDetails['Parse_date'].apply(lambda x: x.strftime("%B"))
        # Getting the year
        custDetails['Year'] = custDetails['Parse_date'].apply(lambda x: x.strftime("%Y"))
        # Getting year and month together as one feature
        custDetails['year_month'] = custDetails['Year'] + "_" +custDetails['Month']

        return custDetails

    def gvCreator(self):
        custDetails = self.dateParser()
        # Creating gross value column
        custDetails['grossValue'] = custDetails[self.config["prod_qnty"]] * custDetails[self.config["unit_price"]]

        return custDetails

The constructor of the DataProcessor class takes the config file as the input and then make it available for all the other methods in line 13.

This dataProcessor class will have three methods, dataLoader, dateParser and gvCreator. The last method is the driving method which internally calls other two methods. Let us look at the gvCreator method.

The dateParser method is called first within the gvCreator method in line 40. The dateParser method in turn calls the dataLoader method in line 23. The dataLoader method loads the customer data as a pandas data frame in line 18 and the passes it to the dateParser method in line 23. The dateParser method takes the custDetails data frame and then extracts all the date related fields from lines 25-35. We saw this in detail during the prototyping phase in the previous post.

Once the dates are parsed in the custDetails data frame, it is passed to gvCreator method in line 40 and then the ‘gross value’ is calcuated by multiplying the unit price and the product quantity. Finally the processed custDetails file is returned.

Now we will come back to the rlRecoMain file and the look at the three other classes, rfmMaker,rlLearn,rlRecomend, we import in line 5 of the file rlRecoMain.py. This is imported from the ‘processes’ folder. Let us look at the composition of the processes folder.

We have three files in the folder, processes.

The first one is the __init__.py file which is the constructor to the package. Let us see its contentes. Open a file and name it __init__.py and add the following lines of code.

from .rfmProcess import rfmMaker
from .selfLearnProcess import rlLearn,rlRecomend

Create customer segmentation modules

In lines 1-2 of the constructor file we make the three classes ( rfmMaker,rlLearn and rlRecomend) available to the package. The class rfmMaker is in the file rfmProcess.py and the other two classes are in the file selfLearnProcess.py.

Let us open a new file, name it rfmProcess.py and then insert the following code.

import sys
sys.path.append('path_to_the_folder/RL_Recomendations/rlreco')
import pandas as pd
import lifetimes
from sklearn.cluster import KMeans
from utils import helperFunctions



class rfmMaker:
    def __init__(self,custDetails,conf):
        self.custDetails = custDetails
        self.conf = conf

    def rfmMatrix(self):
        # Converting data to RFM format
        RfmAgeTrain = lifetimes.utils.summary_data_from_transaction_data(self.custDetails, self.conf['customer_id'], 'Parse_date','grossValue')
        # Reset the index
        RfmAgeTrain = RfmAgeTrain.reset_index()
        return RfmAgeTrain

    # Function for ordering cluster numbers

    def order_cluster(self,cluster_field_name, target_field_name, data, ascending):
        # Group the data on the clusters and summarise the target field(recency/frequency/monetary) based on the mean value
        data_new = data.groupby(cluster_field_name)[target_field_name].mean().reset_index()
        # Sort the data based on the values of the target field
        data_new = data_new.sort_values(by=target_field_name, ascending=ascending).reset_index(drop=True)
        # Create a new column called index for storing the sorted index values
        data_new['index'] = data_new.index
        # Merge the summarised data onto the original data set so that the index is mapped to the cluster
        data_final = pd.merge(data, data_new[[cluster_field_name, 'index']], on=cluster_field_name)
        # From the final data drop the cluster name as the index is the new cluster
        data_final = data_final.drop([cluster_field_name], axis=1)
        # Rename the index column to cluster name
        data_final = data_final.rename(columns={'index': cluster_field_name})
        return data_final

    # Function to do the cluster ordering for each cluster
    #

    def clusterSorter(self,target_field_name,RfmAgeTrain, ascending):
        # Defining the number of clusters
        nclust = self.conf['nclust']
        # Make the subset data frame using the required feature
        user_variable = RfmAgeTrain[['CustomerID', target_field_name]]
        # let us take four clusters indicating 4 quadrants
        kmeans = KMeans(n_clusters=nclust)
        kmeans.fit(user_variable[[target_field_name]])
        # Create the cluster field name from the target field name
        cluster_field_name = target_field_name + 'Cluster'
        # Create the clusters
        user_variable[cluster_field_name] = kmeans.predict(user_variable[[target_field_name]])
        # Sort and reset index
        user_variable.sort_values(by=target_field_name, ascending=ascending).reset_index(drop=True)
        # Sort the data frame according to cluster values
        user_variable = self.order_cluster(cluster_field_name, target_field_name, user_variable, ascending)
        return user_variable


    def clusterCreator(self):
        
        #data : THis is the dataframe for which we want to create the clsuters
        #clustName : This is the variable name
        #nclust ; Numvber of clusters to be created
        
        # Get the RFM data Frame
        RfmAgeTrain = self.rfmMatrix()
        # Implementing for user recency
        user_recency = self.clusterSorter('recency', RfmAgeTrain,False)
        #print('recency grouping',user_recency.groupby('recencyCluster')['recency'].mean().reset_index())
        # Implementing for user frequency
        user_freqency = self.clusterSorter('frequency', RfmAgeTrain, True)
        #print('frequency grouping',user_freqency.groupby('frequencyCluster')['frequency'].mean().reset_index())
        # Implementing for monetary values
        user_monetary = self.clusterSorter('monetary_value', RfmAgeTrain, True)
        #print('monetary grouping',user_monetary.groupby('monetary_valueCluster')['monetary_value'].mean().reset_index())

        # Merging the individual data frames with the main data frame
        RfmAgeTrain = pd.merge(RfmAgeTrain, user_monetary[["CustomerID", 'monetary_valueCluster']], on='CustomerID')
        RfmAgeTrain = pd.merge(RfmAgeTrain, user_freqency[["CustomerID", 'frequencyCluster']], on='CustomerID')
        RfmAgeTrain = pd.merge(RfmAgeTrain, user_recency[["CustomerID", 'recencyCluster']], on='CustomerID')
        # Calculate the overall score
        RfmAgeTrain['OverallScore'] = RfmAgeTrain['recencyCluster'] + RfmAgeTrain['frequencyCluster'] + RfmAgeTrain['monetary_valueCluster']
        return RfmAgeTrain

    def segmenter(self):
        
        #This is the script to create segments after the RFM analysis
        
        # Get the RFM data Frame
        RfmAgeTrain = self.clusterCreator()
        # Segment data
        RfmAgeTrain['Segment'] = 'Q1'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 0), 'Segment'] = 'Q2'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 1), 'Segment'] = 'Q2'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 2), 'Segment'] = 'Q3'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 4), 'Segment'] = 'Q4'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 5), 'Segment'] = 'Q4'
        RfmAgeTrain.loc[(RfmAgeTrain.OverallScore == 6), 'Segment'] = 'Q4'

        # Merging the customer details with the segment
        custDetails = pd.merge(self.custDetails, RfmAgeTrain, on=['CustomerID'], how='left')
        # Saving the details as a pickle file
        helperFunctions.save_clean_data(custDetails,self.conf["custDetails"])
        print("[INFO] Saved customer details ")

        return custDetails

The rfmMaker, class contains methods which does the following tasks,Converting the custDetails data frame to the RFM format. We saw this method in the previous post, where we used the lifetimes library to convert the data frame to the RFM format. This process is detailed in the rfmMatrix method from lines 15-20.

Once the data is made in the RFM format, the next task as we saw in the previous post was to create the clusters for recency, frequency and monetary values. During our prototyping phase we decided to adopt 4 clusters for each of these variables. In this method we will pass the number of clusters through the configuration file as seen in line 44 and then we create these clusters using Kmeans method as shown in lines 48-49. Once the clusters are created, the clusters are sorted to get a logical order. We saw these steps during the prototyping phase and these are implemented using clusterCreator method ( lines 61-85) clusterSorter method ( lines 42-58 ) and orderCluster methods ( lines 24 – 37 ). As the name suggests the first method is to create the cluster and the latter two are to sort it in the logical way. The detailed explanations of these functions are detailed in the last post.

After the clusters are made and sorted, the next task was to merge it with the original data frame. This is done in the latter part of the clusterCreator method ( lines 80-82 ). As we saw in the prototyping phase we merged all the three cluster details to the original data frame and then created the overall score by summing up the scores of each of the individual clusters ( line 84 ) . Finally this data frame is returned to the final method segmenter for defining the segments

Our final task was to combine the clusters to 4 distinct segments as seen from the protoyping phase. We do these steps in the segmenter method ( lines 94-100 ). After these steps we have 4 segments ‘Q1’ to ‘Q4’ and these segments are merged to the custDetails data frame ( line 103 ).

Thats takes us to the end of this post. So let us summarise all our learning so far in this post.

  • Created the folder structure for the project
  • Created a virtual environment and activated the virtual environment
  • Created folders like Config, Data, Processes, Utils and the created the corresponding files
  • Created the code and files for data loading, data clustering and segmenting using the RFM process

We will not get into other aspects of building our self learning system in the next post.

What Next ?

Now that we have explored rfmMaker class in file rfmProcess.py in the next post we will define the classes and methods for implementing the recommendation and self learning processes. The next post will be published next week. To be notified of the next post please subscribe to this blog post .You can also subscribe to our Youtube channel for all the videos related to this series.

The complete code base for the series is in the Bayesian Quest Git hub repository

Do you want to Climb the Machine Learning Knowledge Pyramid ?

Knowledge acquisition is such a liberating experience. The more you invest in your knowledge enhacement, the more empowered you become. The best way to acquire knowledge is by practical application or learn by doing. If you are inspired by the prospect of being empowerd by practical knowledge in Machine learning, subscribe to our Youtube channel

I would also recommend two books I have co-authored. The first one is specialised in deep learning with practical hands on exercises and interactive video and audio aids for learning

This book is accessible using the following links

The Deep Learning Workshop on Amazon

The Deep Learning Workshop on Packt

The second book equips you with practical machine learning skill sets. The pedagogy is through practical interactive exercises and activities.

The Data Science Workshop Book

This book can be accessed using the following links

The Data Science Workshop on Amazon

The Data Science Workshop on Packt

Enjoy your learning experience and be empowered !!!!

VIII : Build and deploy data science products: Machine translation application -Build and deploy using Flask

Source shutterstock.com

One measure of success will be the degree to which you build up others

This is the last post of the series and in this post we finally build and deploy our application we painstakingly developed over the past 7 posts . This series comprises of 8 posts.

  1. Understand the landscape of solutions available for machine translation
  2. Explore sequence to sequence model architecture for machine translation.
  3. Deep dive into the LSTM model with worked out numerical example.
  4. Understand the back propagation algorithm for a LSTM model worked out with a numerical example.
  5. Build a prototype of the machine translation model using a Google colab / Jupyter notebook.
  6. Build the production grade code for the training module using Python scripts.
  7. Building the Machine Translation application -From Prototype to Production : Inference process
  8. Building the Machine Translation application: Build and deploy using Flask : ( This post)

Over the last two posts we covered the factory model and saw how we could build the model during the training phase. We also saw how the model was used for inference. In this section we will take the results of these predictions and build an app using flask. We will progressively work through the different processes of building the application.

Folder Structure

In our journey so far we progressively built many files which were required for the training phase and the inference phase. Now we are getting into the deployment phase were we want to deploy the code we have built into an application. Many of the files which we have built during the earlier phases may not be required anymore in this phase. In addition, we want the application we deploy as light as possible for its performance. For this purpose it is always a good idea to create a seperate folder structure and a new virtual environment for deploying our application. We will only select the necessary files for the deployment purpose. Our final folder structure for this phase will look as follows

Let us progressively build this folder structure and the required files for building our machine translation application.

Setting up and Installing FLASK

When building an application in FLASK , it is always a good practice to create a virtual environment and then complete the application build process within the virtual environment. This way we can ensure that only application specific libraries and packages are deployed into the hosting service. You will see later on that creating a seperate folder and a new virtual environment will be vital for deploying the application in Heroku.

Let us first create a separate folder in our drive and then create a virtual environment within that folder. In a Linux based system, a seperate folder can be created as follows

$ mkdir mtApp

Once the new directory is created let us change directory into the mtApp directory and then create a virtual environment. A virtual environment can be created on Linux with Python3 with the below script

mtApp $ python3 -m venv mtApp

Here the second mtApp is the name of our virtual environment. Do not get confused with the directory we created with the same name. The virtual environment which we created can be activated as below

mtApp $ source mtApp/bin/activate

Once the virtual environment is enabled we will get the following prompt.

(mtApp) ~$

In addition you will notice that a new folder created with the same name as the virtual environment

Our next task is to install all the libraries which are required within the virtual environment we created.

(mtApp) ~$ pip install flask

(mtApp) ~$ pip install tensorflow

(mtApp) ~$ pip install gunicorn

That takes care of all the installations which are required to run our application. Let us now look through the individual folders and the files within it.

There would be three subfolders under the main application folder MTapp. The first subfolder factoryModel is a subset of the corrsponding folder we maintained during the training phase. The second subfolder mtApp is the one created when the virtual environment was created. We dont have to do anything with that folder. The third folder templates is a folder specifically for the flask application. The file app.py is the driver file for the flask application. Let us now looks into each of the folders.

Folder 1 : factoryModel:

The subfolders and files under the factoryModel folder are as shown below. These subfolders and its files are the same as what we have seen during the training phase.

The config folder contains the __init__.py file and the configuration file mt_config.py we used during the training and inference phases.

The output folder contains only a subset of the complete output folder we saw during the inference phase. We need only those files which are required to translate an input German string to English string. The model file we use is the one generated after the training phase.

The utils folder has the same helperFunctions script which we used during the training and inference phase.

Folder 2 : Templates :

The templates folder has two html templates which are required to visualise the outputs from the flask application. We will talk more about the contents of the html file in a short while along with our discussions on the flask app.

Flask Application

Now its time to get to the main part of this article, which is, building the script for the flask application. The code base for the functionalities of the application will be the same as what we have seen during the inference phase. The difference would be in terms of how we use the predictions and visualise them on to the web browser using the flask application.

Let us now open a new file and name is app.py. Let us start building the code in this file

'''
This is the script for flask application
'''

from tensorflow.keras.models import load_model
from factoryModel.config import mt_config as confFile
from factoryModel.utils.helperFunctions import *
from flask import Flask,request,render_template

# Initializing the flask application
app = Flask(__name__)

## Define the file path to the model
modelPath = confFile.MODEL_PATH

# Load the model from the file path
model = load_model(modelPath)

Lines 5-8 imports the required libraries for creating the application

Lines 11 creates the application object ‘app’ as an instance of the class ‘Flask’. The (__name__) variable passed to the Flask class is a predefined variable used in Python to set the name of the module in which it is used.

Line 14 we load the configuration file from the config folder.

Line 17 The model which we created during the training phase is loaded using the load_model() function in Keras.

Next we will load the required pickle files we saved after the training process. In lines 20-22 we intialize the paths to all the files and variables we saved as pickle files during the training phase. These paths are defined in the configuration file. Once the paths are initialized the required files and variables are loaded from the respecive pickle files in lines 24-27. We use the load_files() function we defined in the helper function script for loading the pickle files. You can notice that these steps are same as the ones we used during the inference process.

In the next lines we will explore the visualisation processes for flask application.

@app.route('/')
def home():
	return render_template('home.html')

Lines 29:31 is a feature called the ‘decorator’. A decorator is used to modify the function which comes after it. The function which follows the decorator is a very simple function which returns the html template for our landing page. The landing page of the application is a simple text box where the source language (German) has to be entered. The purpose of the decorator is to build a mapping between the function and the url for the landing page. The URL’s are defined through another important component called ‘routes’ . ‘Routes’ modules are objects which configures the webpages which receives inputs and displays the returned outputs. There are two ‘routes’ which are required for this application, one corresponding to the home page (‘/’) and the second one mapping to another webpage called ‘/translate. The way the decorator, the route and the associated function works together is as follows. The decorator first defines the relationship between the function and the route. The function returns the landing page and route shows the location where the landing page has to be displayed.

Next we will explore the next decorator which return the predictions

@app.route('/translate', methods=['POST', 'GET'])
def get_translation():
    if request.method == 'POST':

        result = request.form
        # Get the German sentence from the Input site
        gerSentence = str(result['input_text'])
        # Converting the text into the required format for prediction
        # Step 1 : Converting to an array
        gerAr = [gerSentence]
        # Clean the input sentence
        cleanText = cleanInput(gerAr)
        # Step 2 : Converting to sequences and padding them
        # Encode the inputsentence as sequence of integers
        seq1 = encode_sequences(Ger_tokenizer, int(Ger_stdlen), cleanText)
        # Step 3 : Get the translation
        translation = generatePredictions(model,Eng_tokenizer,seq1)
        # prediction = model.predict(seq1,verbose=0)[0]

        return render_template('result.html', trans=translation)

Line 33. Our application is designed to accept German sentences as input, translate it to English sentences using the model we built and output the prediction back to the webpage. By default, the routes decorator only receives input i.e ‘GET’ requests. In order to return the predicted words, we have to define a new method in the decorator route called ‘POST’. This is done through the parameters methods=['POST','GET'] in the decorator.

Line 34. is the main function which translates the input German sentences to English sentences and then display the predictions on to the webpage.

Line 35, defines the ‘if’ method to ascertain that there is a ‘POST’ method which is involved in the operation. The next line is where we define the web form which is used for getting the inputs from the application. Web forms are like templates which are used for receiving inputs from the users and also returning the output.

In Line 37 we define the request.form into a new variable called result. All the outputs from the web forms will be accessible through the variable result.There are two web forms which we use in the application ‘home.html’ and ‘result.html’.

By default the webforms have to reside in a folder called Templates. Before we proceed with the rest of the code within the function we have to understand the webforms. Therefore let us build them. Open a new file and name it home.html and copy the following code.

<!DOCTYPE html>

<html>
<title>Machine Translation APP</title>
<body>
<form action = "/translate" method= "POST">

	<h3> German Sentence: </h3>

	<th> <input name='input_text' type="text" value = " " /> </th>

	<p><input type = "submit" value = "submit" /></p>

</form>
</body>
</html>	

The prediction process in our application is initiated when we get the input German text from the ‘home.html’ form. In ‘home.html’ we define the variable name ( ‘input_text’ : line 10 in home.html) for getting the German text as input. A default value can also be mentioned using the variable value which will be over written when a new text is given as input. We also specify a submit button for submitting the input German sentence through the form, line 12.

Line 39 : As seen in line 37, the inputs from the web form will be stored in the variable result. Now to access the input text which is stored in a variable called ‘input_text’ within home.html, we have to call it as ‘input_text’ from the result variable ( result['input_text']. This input text is there by stored into a variable ‘gerSentence’ as a string.

Line 42 the string object we received from the earlier line is converted to a list as required during prediction process.

Line 44, we clean the input text using the cleanInput() function we import from the helperfunctions. After cleaning the text we need to convert the input text into a sequence of integers which is done in line 47. Finally in line 49, we generate the predicted English sentences.

For visualizing the translation we use the second html template result.html. Let us quickly review the template

<!DOCTYPE html>
<html>
<title>Machine Translation APP</title>

    <body>
          <h3> English Translation:  </h3>
            <tr>
                <th> {{ trans }} </th>
            </tr>
    </body>
</html>

This template is a very simple one where the only varible of interest is on line 8 which is the variable trans.

The translation generated is relayed to result.html in line 51 by assigning the translation to the parameter trans .

if __name__ == '__main__':
    app.debug = True
    app.run()

Finally to run the app, the app.run() method has to be invoked as in line 56.

Let us now execute the application on the terminal. To execute the application run $ python app.py on the terminal. Always ensure that the terminal is pointing to the virtual environment we initialized earlier.

When the command is executed you should expect to get the following screen

Click the url or copy the url on a browser to see the application you build come live on your browser.

Congratulations you have your application running on the browser. Keep entering the German sentences you want to translate and see how the application performs.

Deploying the application

You have come a long way from where you began. You have now built an application using your deep learning model. Now the next question is where to go from here. The obvious route is to deploy the application on a production server so that your application is accessible to users on the web. We have different deployment options available. Some popular ones are

  • Heroku
  • Google APP engine
  • AWS
  • Azure
  • Python Anywhere …… etc.

What ever be the option you choose, deploying an application of this size will be best achieved by subscribing a paid service on any of these options. However just to go through the motions and demonstrate the process let us try to deploy the application on the free option of Heroku.

Deployment Process on Heroku

Heroku offers a free version for deployment however there are restrictions on the size of the application which can be hosted as a free service. Unfortunately our application would be much larger than the one allowed on the free version. However, here I would like to demonstrate the process of deploying the application on Heroku.

Step 1 : Creating the Heroku account.

The first step in the process is to create an account with Heroku. This can be done through the link https://www.heroku.com/. Once an account is created we get access to a dashboard which lists all the applications which we host in the platform.

Step 2 : Configuring git

Configuring ‘git’ is vital for deploying applications to Heroku. Git has to be installed first to our local system to make the deployment work. Git can be installed by following instructions in the link https://git-scm.com/book/en/v2/Getting-Started-Installing-Git.

Once ‘git’ is installed it has to be configured with your user name and email id.

$ git config –global user.name “user.name”

$ git config –global user.email userName@mail.com

Step 3 : Installing Heroku CLI

The next step is to install the Heroku CLI and the logging in to the Heroku CLI. The detailed steps which are involved for installing the Heroku CLI are given in this link

https://devcenter.heroku.com/articles/heroku-cli

If you are using Ubantu system you can install Heroku CLI using the script below

$ sudo snap install heroku --classic

Once Heroku is installed we need to log into the CLI once. This is done in the terminal with the following command

$ heroku login

Step 4 : Creating the Procfile and requirements.txt

There is a file called ‘Procfile’ in the root folder of the application which gives instructions on starting the application.

Procfile and requirements.txt in the application folder

The file can be created using any text editor and should be saved in the name ‘Procfile’. No extension should be specified for the file. The contents of the file should be as follows

web: gunicorn app:app --log-file

Another important pre-requisite for the Heroku application is a file called ‘requirements.txt’. This is a file which lists down all the dependencies which needs to be installed for running the application. The requirements.txt file can be created using the below command.

$ pip freeze > requirements.txt

Step 5 : Initializing git and copying the required dependent files to Heroku

The above steps creates the basic files which are required for running the application. The next task is to initialize git on the folder. To initialize git we need to go into the root folder where the app.py file exists and then initialize it with the below command

$ git init

Step 6 : Create application instance in Heroku

In order for git to push the application file to the remote Heroku server, an instance of the application needs to be created in Heroku. The command for creating the application instance is as shown below.

$ heroku create {application name}

Please replace the braces with the application name of your choice. For example if the application name you choose is 'gerengtran', it has to be enabled as follows

$ heroku create gerengtran

Step 7 : Pushing the application files to remote server

Once git is initialized and an instance of the application is created in Heroku, the application files can be set up in remote Heroku server by the following commands.

$ heroku git:remote -a {application name}

Please note that ‘application_name’ is the name of the application which you have chosen earlier. What ever name you choose will be the name of the application in Heroku. The external link to your application will be in the name which you choose here.

Step 8 : Deploying the application and making it available as a web app

The final step of the process is to complete the deployment on Heroku and making the application available as a web app. This process starts with the command to add all the changes which you made to git.

$ git add .

Please note that there is a full stop( ‘.’ ) as part of the script after ‘add’ with a space in between .

After adding all the changes, we need to commit all the changes before finally deploying the application.

$ git commit -am "First submission"

The deployment will be completed with the below script after which the application will be up and running as a web app.

$ git push heroku master

When the files are pushed, if the deployment is successful you will get a url which is the link to the application. Alternatively, you can also go to Heroku console and activate your application. Below is the view of your console with all the applications listed. The application with the red box is the application which has been deployed

If you click on the link of the application ( red box) you get the link where the application can be open.

When the open app button is clicked the application is opened in a browser.

Wrapping up the series

With this we have achieved a good milestone of building an application and deploying it on the web for others to consume. I am a strong believer that learning data science should be to enrich products and services. And the best way to learn how to enrich products and services is to build it yourselves at a smaller scale. I hope you would have gained a lot of confidence by building your application and then deploying them on the web. Before we bid adeau, to this series let us summarise what we have achieved in this series and list of the next steps

In this series we first understood the solution landscape of machine translation applications and then understood different architecture choices. In the third and fourth posts we dived into the mathematics of a LSTM model where we worked out a toy example for deriving the forward pass and backpropagation. In the subsequent posts we got down to the tasks of building our application. First we built a prototype and then converted it into production grade code. Finally we wrapped the functionalities we developed in a Flask application and understood the process of deploying it on Heroku.

You have definitely come a long way.

However looking back are there avenues for improvement ? Absolutely !!!

First of all the model we built is a simple one. Machine translation is a complex process which requires lot more sophisticated models for better results. Some of the model choices you can try out are the following

  1. Change the model architecture. Experiment with different number of units and number of layers. Try variations like bidirectional LSTM
  2. Use attention mechanisms on the LSTM layers. Attention mechanism is see to have given good performance on machine translation tasks
  3. Move away from sequence to sequence models and use state of the art models like Transformers.

The second set of optimizations you can try out are on the vizualisations of the flask application. The templates which are used here are very basic templates. You can further experiment with different templates and make the application visually attractive.

The final improvement areas are in the choices of deployment platforms. I would urge you to try out other deployment choices and let me know the results.

I hope all of you enjoyed this series. I definitely enjoyed writing this post. Hope it benefits you and enable you to improve upon the methods used here.

I will be back again with more practical application building series like this. Watch this space for more

You can download the code for the deployment process from the following link

https://github.com/BayesianQuest/MachineTranslation/tree/master/Deployment/MTapp

Do you want to Climb the Machine Learning Knowledge Pyramid ?

Knowledge acquisition is such a liberating experience. The more you invest in your knowledge enhacement, the more empowered you become. The best way to acquire knowledge is by practical application or learn by doing. If you are inspired by the prospect of being empowerd by practical knowledge in Machine learning, I would recommend two books I have co-authored. The first one is specialised in deep learning with practical hands on exercises and interactive video and audio aids for learning

This book is accessible using the following links

The Deep Learning Workshop on Amazon

The Deep Learning Workshop on Packt

The second book equips you with practical machine learning skill sets. The pedagogy is through practical interactive exercises and activities.

This book can be accessed using the following links

The Data Science Workshop on Amazon

The Data Science Workshop on Packt

Enjoy your learning experience and be empowered !!!!

VII Build and deploy data science products: Machine translation application – From Prototype to Production for Inference process

Image source : macadamian.com

“To contrive is nothing! To consruct is something ! To produce is everything !”

Edward Rickenbacker

This is the seventh part of the series in which we continue our endeavour in building the inference process for our machine translation application. This series comprises of 8 posts.

  1. Understand the landscape of solutions available for machine translation
  2. Explore sequence to sequence model architecture for machine translation.
  3. Deep dive into the LSTM model with worked out numerical example.
  4. Understand the back propagation algorithm for a LSTM model worked out with a numerical example.
  5. Build a prototype of the machine translation model using a Google colab / Jupyter notebook.
  6. Build the production grade code for the training module using Python scripts.
  7. Building the Machine Translation application -From Prototype to Production : Inference process ( This post)
  8. Build the machine translation application using Flask and understand the process to deploy the application on Heroku

In the last post of the series we covered the training process. We built the model and then saved all the variables as pickle files. We will be using the model we developed during the training phase for the inference process. Let us dive in and look at the project structure, which would be similar to the one we saw in the last post.

Project Structure

Let us first look at the helper function file. We will be adding new functions and configuration variables to the file we introduced in the last post.

Let us first look at the configuration file.

Configuration File

Open the configuration file mt_config.py , we used in the last post and add the following lines.

# Define the path where the model is saved
MODEL_PATH = path.sep.join([BASE_PATH,'factoryModel/output/model.h5'])
# Defin the path to the tokenizer
ENG_TOK_PATH = path.sep.join([BASE_PATH,'factoryModel/output/eng_tokenizer.pkl'])
GER_TOK_PATH = path.sep.join([BASE_PATH,'factoryModel/output/deu_tokenizer.pkl'])
# Path to Standard lengths of German and English sentences
GER_STDLEN = path.sep.join([BASE_PATH,'factoryModel/output/ger_length.pkl'])
ENG_STDLEN = path.sep.join([BASE_PATH,'factoryModel/output/eng_length.pkl'])
# Path to the test sets
TEST_X = path.sep.join([BASE_PATH,'factoryModel/output/testX.pkl'])
TEST_Y = path.sep.join([BASE_PATH,'factoryModel/output/testY.pkl'])

Lines 14-23 we add the paths for many of the files and variables we created during the training process.

Line 14 is the path to the model file which was created after the training. We will be using this model for the inference process

Lines 16-17 are the paths to the English and German tokenizers

Lines 19-20 are the variables for the standard lengths of the German and English sequences

Lines 21-23 are the test sets which we will use to predict and evaluate our model.

Utils Folder : Helper functions

Having seen the configuration file, let us now review all the helper functions for the application. In the training phase we created a helper function file called helperFunctions.py. Let us go ahead and revisit that file and add more functions required for the application.

'''
This script lists down all the helper functions which are required for processing raw data
'''

from pickle import load
from numpy import argmax
from pickle import dump
from tensorflow.keras.preprocessing.sequence import pad_sequences
from numpy import array
from unicodedata import normalize
import string

# Function to Save data to pickle form
def save_clean_data(data,filename):
    dump(data,open(filename,'wb'))
    print('Saved: %s' % filename)

# Function to load pickle data from disk
def load_files(filename):
    return load(open(filename,'rb'))

Lines 5-11 as usual are the library packages which are required for the application.

Line 14 is the function to save data as a pickle file. We saw this function in the last post.

Lines 19-20 is a utility function to load a pickle file from disk. The parameter to this function is the path of the file.

In the last post we saw a detailed function for cleaning raw data to finally generate the training and test sets. For the inference process we need an abridged version of that function.

# Function to clean the input data
def cleanInput(lines):
    cleanSent = []
    cleanDocs = list()
    for docs in lines[0].split():
        line = normalize('NFD', docs).encode('ascii', 'ignore')
        line = line.decode('UTF-8')
        line = [line.translate(str.maketrans('', '', string.punctuation))]
        line = line[0].lower()
        cleanDocs.append(line)
    cleanSent.append(' '.join(cleanDocs))
    return array(cleanSent)

Line 23 initializes the cleaning function for the input sentences. In this function we assume that the input sentence would be a string and therefore in line 26 we split the string into individual words and iterate through each of the words. Lines 27-28 we normalize the input words to the ascii format. We remove all punctuations in line 29 and then convert the words to lower case in line 30. Finally we join inividual words to a string in line 32 and return the cleaned sentence.

The next function we will insert is the sequence encoder we saw in the last post. Add the following lines to the script

# Function to convert sentences to sequences of integers
def encode_sequences(tokenizer,length,lines):
    # Sequences as integers
    X = tokenizer.texts_to_sequences(lines)
    # Padding the sentences with 0
    X = pad_sequences(X,maxlen=length,padding='post')
    return X

As seen earlier the parameters are the tokenizer, the standard length and the source data as seen in Line 36.

The sentence is converted into integer sequences using the tokenizer as shown in line 38. The encoded integer sequences are made to standard length in line 40 using the padding function.

We will now look at the utility function to convert integer sequences to words.

# Generate target sentence given source sequence
def Convertsequence(tokenizer,source):
    target = list()
    reverse_eng = tokenizer.index_word
    for i in source:
        if i == 0:
            continue
        target.append(reverse_eng[int(i)])
    return ' '.join(target)

We initialize the function in line 44. The parameters to the function are the tokenizer and the source, a list of integers, which needs to be converted into the corresponding words.

In line 46 we define a reverse dictionary from the tokenizer. The reverse dictionary gives you the word in the vocabulary if you give the corresponding index.

In line 47 we iterate through each of the integers in the list . In line 48-49, we ignore the word if the index is 0 as this could be a padded integer. In line 50 we get the word corresponding to the index integer using the reverse dictionary and then append it to the placeholder list created earlier in line 45. All the words which are appended into the placeholder list are then joined together to a string in line 51 and then returned

Next we will review one of the most important functions, a function for generating predictions and the converting the predictions into text form. As seen from the post where we built the prototype, the predict function generates an array which has the same length as the number of maximum sequences and depth equal to the size of the vocabulary of the target language. The depth axis gives you the probability of words accross all the words of the vocabulary. The final predictions have to be transformed from this array format into a text format so that we can easily evaluate our predictions.

# Function to generate predictions from source data
def generatePredictions(model,tokenizer,data):
    prediction = model.predict(data,verbose=0)    
    AllPreds = []
    for i in range(len(prediction)):
        predIndex = [argmax(prediction[i, :, :], axis=-1)][0]
        target = Convertsequence(tokenizer,predIndex)
        AllPreds.append(target)
    return AllPreds

We initialize the function in line 54. The parameters to the function are the trained model, English tokenizer and the data we want to translate. The data to translate has to be in an array form of dimensions ( num of examples, sequence length).

We generate the prediction in line 55 using the model.predict() method. The predicted output object ( prediction) is an array of dimensions ( num_examples, sequence length, size of english vocabulary)

We initialize a list to store all the predictions on line 56.

Lines 57-58,we iterate through all the examples and then generate the index which has the maximum probability in the last axis of the prediction array. The last axis of the predictions array will be a probability distribution over the words of the target vocabulary. We need to get the index of the word which has the maximum probability. This is what we use the argmax function.

This image has an empty alt attribute; its file name is image-23.png

As shown in the representative figure above by taking the argmax of the last axis ( axis = -1) we obtain the index position where the probability of words accross all the words of the vocabulary is the greatest. The output we get from line 58 is a list of the indexes of the vocabulary where the probability is highest as shown in the list below

[ 5, 123, 4, 3052, 0]

In line 59 we convert the above list of integers to a string using the Convertsequence() function we saw earlier. All the predicted strings are then appended to a placeholder list and returned in lines 60-61

Inference Process

Having seen the helper functions, let us now explore the inference process. Let us open a new file and name it mt_Inference.py and enter the following code.

'''
This is the driver file for the inference process
'''

from tensorflow.keras.models import load_model
from factoryModel.config import mt_config as confFile
from factoryModel.utils.helperFunctions import *

## Define the file path to the model
modelPath = confFile.MODEL_PATH

# Load the model from the file path
model = load_model(modelPath)

We import all the required functions in lines 5-7. In line 7 we import all the helper functions we created above. We then initiate the path to the model from the configuration file in line 10.

Once the path to the model is initialized then it is the turn to load the model we saved during the training phase. In line 13 we load the saved model from the path using the Keras function load_model().

Next we load the required pickle files we saved after the training process.

# Get the paths for all the files and variables stored as pickle files
Eng_tokPath = confFile.ENG_TOK_PATH
Ger_tokPath = confFile.GER_TOK_PATH
testxPath = confFile.TEST_X
testyPath = confFile.TEST_Y
Ger_length = confFile.GER_STDLEN
# Load the tokenizer from the pickle file
Eng_tokenizer = load_files(Eng_tokPath)
Ger_tokenizer = load_files(Ger_tokPath)
# Load the standard lengths
Ger_stdlen = load_files(Ger_length)
# Load the test sets
testX = load_files(testxPath)
testY = load_files(testyPath)

On lines 16-20 we intialize the paths to all the files and variables we saved as pickle files during the training phase. These paths are defined in the configuration file. Once the paths are initialized the required files and variables are loaded from the respecive pickle files in lines 22-28. We use the load_files() function we defined in the helper function script for loading the pickle files.

The next step is to generate the predictions for the test set. We already defined the function for generating predictions as part of the helper functions script. We will be calling that function to generate the predictions.

# Generate predictions
predSent = generatePredictions(model,Eng_tokenizer,testX[0:20,:])

for i in range(len(testY[0:20])):
    targetY = Convertsequence(Eng_tokenizer,testY[i:i+1][0])
    print("Original sentence : {} :: Prediction : {}".format([targetY],[predSent[i]]))

On line 31 we generate the predictions on the test set using the generatePredictions() function. We provide the model , the English tokenizer and the first 20 sequences of the test set for generating the predictions.

Once the predictions are generated let us look at how good our predictions are by comparing it against the original sentence. In line 33-34 we loop through the first 20 target English integer sequences and convert them into the respective English sentences using the Convertsequence() function defined earlier. We then print out our predictions and the original sentence on line 35.

The output will be similar to the one we got during the prototype phase as we havent changed the model parameters during the training phase.

Predicting on our own sentences

When we predict on our own input sentences we have to preprocess the input sentence by cleaning it and then converting it into a sequence of integers. We have already made the required functions for doing that in our helper functions file. The next thing we want is a place to enter the input sentence. Let us provide our input sentence in our configuration file itself.

Let us open the configuration file mt_config.py and add the following at the end of the file.

######## German Sentence for Translation ###############

GER_SENTENCE = 'heute ist ein guter Tag'

In line 27 we define a configuration variable GER_SENTENCE to store the sentences we want to input. We have provided a string 'heute ist ein guter Tag' which means ‘Today is a good day’ as the input string. You are free to input any German sentence you want at this location. Please note that the sentence have to be inside quotes ' '.

Let us now look at how our input sentences can be translated using the inference process. Open the mt_inference.py file and add the following code below the existing code.

############# Prediction of your Own sentences ##################

# Get the input sentence from the config file
inputSentence = [confFile.GER_SENTENCE]

# Clean the input sentence
cleanText = cleanInput(inputSentence)

# Encode the inputsentence as sequence of integers
seq1 = encode_sequences(Ger_tokenizer,int(Ger_stdlen),cleanText)

print("[INFO] .... Predicting on own sentences...")

# Generate the prediction
predSent = generatePredictions(model,Eng_tokenizer,seq1)
print("Original sentence : {} :: Prediction : {}".format([cleanText[0]],predSent))

In line 40 we access the input sentence from the configuration file. We wrap the input string in a list [ ].

In line 43 we do a basic cleaning for the input sentence. We do it using the cleanInput() function we created in the helper function file. Next we encode the cleaned text as integer sequences in line 46. Finally we generate our prediction on line 51 and print out the results in line 52.

Wrapping up

Hurrah!!!! we have come to the end of the inference process. In this post you learned how to generate predictions on the test set. We also predicted our own sentences. We have come a long way and we are ready to make the final lap. Next we will make machine translation application using flask.

Go to article 8 of this series : Building the machine translation application using Flask and deploying on Heroku

You can download the notebook for the inference process using the following link

https://github.com/BayesianQuest/MachineTranslation/tree/master/Production

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