Generating recommendation model for a large dataset using spark - scala

Question

I'm trying out to generate a simple ALS model using the spark documentation here.
My first file(ratings.csv) has 20million UserID,MovID,Rat and can be downloaded here
So I have the testing data which is a subset of ratings.csv. That test dataset can be downloaded here:
The test file has just the UserID, Movie ID column.
So to create training data we will have to filter ratings.csv.
The following code is working fine for a smaller case of 100,000 UserID,MovID rating. I am not able to generate the model for the big case.
Please help with a pointer.
/**
* Created by echoesofconc on 3/8/17.
*/
import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.rdd.RDD
import org.apache.spark.mllib.recommendation.ALS
import org.apache.spark.mllib.recommendation.MatrixFactorizationModel
import org.apache.spark.mllib.recommendation.Rating
import java.io._
import scala.collection.mutable.ListBuffer
object Prateek_Agrawal_task1 {
def dropheader(data: RDD[String]): RDD[String] = {
data.mapPartitionsWithIndex((idx, lines) => {
if (idx == 0) {
lines.drop(1)
}
lines
})
}
def create_training(ratings_split: RDD[Array[String]], ratings_testing: Array[Array[String]]) = {
ratings_split.filter(x => {
ratings_testing.exists(y =>
(x(0) == y(0) && x(1) == y(1))
) == false
})
}
def create_testing(ratings_split: RDD[Array[String]], ratings_testing: Array[Array[String]]) = {
ratings_split.filter(x => {
ratings_testing.exists(y =>
(x(0) == y(0) && x(1) == y(1))
) == true
})
}
def create_model(ratings_train:RDD[Array[String]],rank:Int,numIterations:Int ):org.apache.spark.mllib.recommendation.MatrixFactorizationModel={
val ratings = ratings_train.map(_ match { case Array(user,item,rate,temp) =>
Rating(user.toInt, item.toInt, rate.toDouble)
})
val model = ALS.train(ratings, rank, numIterations, 0.01)
return model
}
def print_results(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val rating_range=final_predictions_adjusted.map(x=>(x._2.toInt,1)).reduceByKey(_+_).sortByKey()
val rating_range_till_4=rating_range.map{x=>
var temp=x
if (x._1==5){temp=(4,x._2)}
temp
}.reduceByKey(_+_)
rating_range_till_4.sortByKey().foreach { x =>
if(x._1==0)
printf(">=0 and <1: " + x._2+"\n")
if(x._1==1)
printf(">=1 and <2: " + x._2+"\n")
if(x._1==2)
printf(">=2 and <3: " + x._2+"\n")
if(x._1==3)
printf(">=3 and <4: " + x._2+"\n")
if(x._1==4)
printf(">=4 " + x._2+"\n")
if(x._1==5)
printf("=5 " + x._2+"\n")
}
}
case class User_mov_rat(UserID: Int, MovieID:Int, Pred_rating: Double)
def print_outputfile(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val writer = new FileWriter(new File("./output.txt" ))
writer.write("UserID,MovieID,Pred_rating\n")
final_predictions_adjusted.collect().foreach(x=>{writer.write(x._1._1+","+x._1._2+","+x._2+"\n")})
writer.close()
}
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setAppName("Prateek_Agrawal_task1").setMaster("local[2]")
val sc = new SparkContext(conf)
val file = "/Users/echoesofconc/Documents/USC_courses/INF553/ml-20m/ratings.csv"
val test = "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/testing_20m.csv"
val data = sc.textFile(file, 2).cache()
val data_test = sc.textFile(test, 2).cache()
// Drop Header
val data_wo_header=dropheader(data).persist()
val data_test_wo_header=dropheader(data_test).persist()
// Create Training and testing data of the format (User ID, MovID, Rating, Time)
val ratings_split = data_wo_header.map(line => line.split(",")).persist()
data_wo_header.unpersist()
data.unpersist()
val ratings_testing = data_test_wo_header.map(line => line.split(",")).collect()
data_test_wo_header.unpersist()
data_test.unpersist()
val ratings_train = create_training(ratings_split, ratings_testing).persist()
val ratings_test=create_testing(ratings_split, ratings_testing)
ratings_split.unpersist()
ratings_test.unpersist()
// Create the model using rating_train the training data
val rank = 1
val numIterations = 10
val model=create_model(ratings_train,rank,numIterations)
ratings_train.unpersist()
// Average user,Rating from training this is for cases which are there in test but not rated by any user in training
val user_avgrat=ratings_test.map(_ match { case Array(user, mov, rate, temp) =>(user.toInt, (rate.toDouble,1.0))}).reduceByKey((x,y)=>(x._1 + y._1, x._2 + y._2)).mapValues{ case (sum, count) => (1.0 * sum) / count }
// Predict user_mov ratings
val user_mov = data_test_wo_header.map(_.split(',') match { case Array(user, mov) =>
(user.toInt,mov.toInt)
})
val predictions =
model.predict(user_mov).map { case Rating(user, mov, rate) =>
((user, mov), rate)
}
// Combine Predictions and unpredicted user,Movies due to them being individual. Going forward we need to improve the accuracy for these predictions
val user_mov_rat=user_mov.map(x=>(x,0.0))
val predictions_unpredicted_combined= predictions.union(user_mov_rat).reduceByKey(_+_).map(x=>(x._1._1,(x._1._2,x._2)))
// Combine average rating and predictions+unpredicted values
val avg_rating_predictions_unpredicted_combined=predictions_unpredicted_combined.join(user_avgrat)
// Generate final predictions RDD
val final_predictions=avg_rating_predictions_unpredicted_combined.map{x=>
var temp=((x._1,x._2._1._1),x._2._2)
if(x._2._1._2==0.0){temp=((x._1,x._2._1._1),x._2._2)}
if(x._2._1._2!=0.0){temp=((x._1,x._2._1._1),x._2._1._2)}
temp
}
// Adjust for ratings above 5.0 and below 0.0
val final_predictions_adjusted=final_predictions.map{x=>
var temp=x
if (x._2>5.0){temp=(x._1,5.0)}
if (x._2<0.0){temp=(x._1,0.0)}
temp
}
val ratesAndPreds = ratings_test.map(_ match { case Array(user, mov, rate, temp) => ((user.toInt,mov.toInt),rate.toDouble)}).join(final_predictions_adjusted)
val MSE = ratesAndPreds.map { case ((user, product), (r1, r2)) =>
val err = (r1 - r2)
err * err
}.mean()
val RMSE=math.sqrt(MSE)
// Print output.txt
print_outputfile(final_predictions_adjusted)
// Print the predictionresults
print_results(final_predictions_adjusted.sortByKey())
print(RMSE+"\n")
}
}
In case someone thinks I should be doing a regex match I have tried that approach. BUt that dosen't seem to be a bottleneck.
I only need to complete the create model part on which I am stuck for the big dataset. Can somebody help.
EDIT:
Another approach I tried which is much faster by using broadcast variables. But it's been running for 12 hrs with no signs of progress. On spark UI somehow the whole of the RDD(ratings.csv ~500MB) is not cached. Only around 64MB with 2.5 Million lines is being processed initially. I am using --executor-memory -8g. I have modified the create_training create_testing functions:
/**
* Created by echoesofconc on 3/8/17.
*/
import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.rdd.RDD
import org.apache.spark.mllib.recommendation.ALS
import org.apache.spark.mllib.recommendation.Rating
import java.io._
object Prateek_Agrawal_task2 {
def dropheader(data: RDD[String]): RDD[String] = {
data.mapPartitionsWithIndex((idx, lines) => {
if (idx == 0) {
lines.drop(1)
}
lines
})
}
def create_training(data_wo_header: RDD[String], data_test_wo_header: RDD[String],sc:SparkContext): RDD[String] = {
val rdd2array = sc.broadcast(data_test_wo_header.collect())
val training_set = data_wo_header.filter{
case(x) => rdd2array.value.filter(y => x.indexOf(y.toString())==0).length == 0
}
return training_set
}
def create_test(data_wo_header: RDD[String], data_test_wo_header: RDD[String],sc:SparkContext): RDD[String] = {
val rdd2array = sc.broadcast(data_test_wo_header.collect())
val training_set = data_wo_header.filter{
case(x) => rdd2array.value.filter(y => x.indexOf(y.toString())==0).length != 0
}
return training_set
}
def create_model(ratings_train:RDD[String],rank:Int,numIterations:Int ):org.apache.spark.mllib.recommendation.MatrixFactorizationModel={
val ratings = ratings_train.map(_.split(',') match { case Array(user, item, rate, timestamp) =>
Rating(user.toInt, item.toInt, rate.toDouble)
})
val model = ALS.train(ratings, rank, numIterations, 0.01)
return model
}
def print_results(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val rating_range=final_predictions_adjusted.map(x=>(x._2.toInt,1)).reduceByKey(_+_).sortByKey()
val rating_range_till_4=rating_range.map{x=>
var temp=x
if (x._1==5){temp=(4,x._2)}
temp
}.reduceByKey(_+_)
rating_range_till_4.sortByKey().foreach { x =>
if(x._1==0)
printf(">=0 and <1: " + x._2+"\n")
if(x._1==1)
printf(">=1 and <2: " + x._2+"\n")
if(x._1==2)
printf(">=2 and <3: " + x._2+"\n")
if(x._1==3)
printf(">=3 and <4: " + x._2+"\n")
if(x._1==4)
printf(">=4 " + x._2+"\n")
if(x._1==5)
printf("=5 " + x._2+"\n")
}
}
case class User_mov_rat(UserID: Int, MovieID:Int, Pred_rating: Double)
def print_outputfile(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val writer = new FileWriter(new File("./output.txt" ))
writer.write("UserID,MovieID,Pred_rating\n")
final_predictions_adjusted.collect().foreach(x=>{writer.write(x._1._1+","+x._1._2+","+x._2+"\n")})
writer.close()
}
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setAppName("Prateek_Agrawal_task1").setMaster("local[2]")
val sc = new SparkContext(conf)
val file = "/Users/echoesofconc/Documents/USC_courses/INF553/ml-latest-small/ratings.csv"
val test = "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/testing_small.csv"
// val file = "/Users/echoesofconc/Documents/USC_courses/INF553/ml-20m/ratings.csv"
// val test = "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/testing_20m.csv"
val data = sc.textFile(file, 2).persist()
val data_test = sc.textFile(test, 2).persist()
// Drop Header
val data_wo_header=dropheader(data)
val data_test_wo_header=dropheader(data_test)
// Create Traing and testing data of the format (User ID, MovID, Rating, Time)
val ratings_train=create_training(data_wo_header,data_test_wo_header,sc).persist()
val ratings_test=create_test(data_wo_header,data_test_wo_header,sc)
// val ratings_test=create_test(data_wo_header,data_test_wo_header,sc)
// data_test_wo_header.unpersist()
// data_test.unpersist()
//// data.unpersist()
//// data_test.unpersist()
// Create the model using rating_train the training data
val rank = 1
val numIterations = 10
val model=create_model(ratings_train,rank,numIterations)
// ratings_train.unpersist()
// model.save(sc, "target/tmp/myCollaborativeFilter")
// val Model = MatrixFactorizationModel.load(sc, "/Users/echoesofconc/myCollaborativeFilter")
// Average user,Rating from training
val user_avgrat=ratings_test.map(_.split(",") match { case Array(user, mov, rate, temp) =>(user.toInt, (rate.toDouble,1.0))}).reduceByKey((x,y)=>(x._1 + y._1, x._2 + y._2)).mapValues{ case (sum, count) => (1.0 * sum) / count }
//data
// Predict user_mov ratings
val user_mov = data_test_wo_header.map(_.split(',') match { case Array(user, mov) =>
(user.toInt,mov.toInt)
})
val predictions =
model.predict(user_mov).map { case Rating(user, mov, rate) =>
((user, mov), rate)
}
// Combine Predictions and unpredicted user,Movies due to them being individual. Going forward we need to improve the accuracy for these predictions
val user_mov_rat=user_mov.map(x=>(x,0.0))
val predictions_unpredicted_combined= predictions.union(user_mov_rat).reduceByKey(_+_).map(x=>(x._1._1,(x._1._2,x._2)))
// Combine average rating and predictions+unpredicted values
val avg_rating_predictions_unpredicted_combined=predictions_unpredicted_combined.join(user_avgrat)
// Generate final predictions RDD
val final_predictions=avg_rating_predictions_unpredicted_combined.map{x=>
var temp=((x._1,x._2._1._1),x._2._2)
if(x._2._1._2==0.0){temp=((x._1,x._2._1._1),x._2._2)}
if(x._2._1._2!=0.0){temp=((x._1,x._2._1._1),x._2._1._2)}
temp
}
// Adjust for ratings above 5.0 and below 0.0
val final_predictions_adjusted=final_predictions.map{x=>
var temp=x
if (x._2>5.0){temp=(x._1,5.0)}
if (x._2<0.0){temp=(x._1,0.0)}
temp
}
val ratesAndPreds = ratings_test.map(_.split(",") match { case Array(user, mov, rate, temp) => ((user.toInt,mov.toInt),rate.toDouble)}).join(final_predictions_adjusted)
val MSE = ratesAndPreds.map { case ((user, product), (r1, r2)) =>
val err = (r1 - r2)
err * err
}.mean()
val RMSE=math.sqrt(MSE)
// Print output.txt
print_outputfile(final_predictions_adjusted)
// Print the predictionresults
print_results(final_predictions_adjusted.sortByKey())
print(RMSE+"\n")
}
}

Answer 1

This worked out to be fine. It's using join to create testng training data
/**
* Created by echoesofconc on 3/8/17.
*/
import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.rdd.RDD
import org.apache.spark.mllib.recommendation.ALS
import org.apache.spark.mllib.recommendation.Rating
import org.apache.spark.mllib.recommendation.MatrixFactorizationModel
import java.io._
object Prateek_Agrawal_task1 {
def dropheader(data: RDD[String]): RDD[String] = {
data.mapPartitionsWithIndex((idx, lines) => {
if (idx == 0) {
lines.drop(1)
}
lines
})
}
def create_training(ratings_split: RDD[Array[String]], ratings_testing: Array[Array[String]]) = {
ratings_split.filter(x => {
ratings_testing.exists(y =>
(x(0) == y(0) && x(1) == y(1))
) == false
})
}
def create_testing(ratings_split: RDD[Array[String]], ratings_testing: Array[Array[String]]) = {
ratings_split.filter(x => {
ratings_testing.exists(y =>
(x(0) == y(0) && x(1) == y(1))
) == true
})
}
def create_model(ratings_train:RDD[((String, String), (String, String))],rank:Int,numIterations:Int ):org.apache.spark.mllib.recommendation.MatrixFactorizationModel={
val ratings = ratings_train.map(_ match { case ((user,item),(rate,temp)) =>
Rating(user.toInt, item.toInt, rate.toDouble)
})
val model = ALS.train(ratings, rank, numIterations, 0.01)
return model
}
def print_results(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val rating_range=final_predictions_adjusted.map(x=>(x._2.toInt,1)).reduceByKey(_+_).sortByKey()
val rating_range_till_4=rating_range.map{x=>
var temp=x
if (x._1==5){temp=(4,x._2)}
temp
}.reduceByKey(_+_)
rating_range_till_4.sortByKey().foreach { x =>
if(x._1==0)
printf(">=0 and <1: " + x._2+"\n")
if(x._1==1)
printf(">=1 and <2: " + x._2+"\n")
if(x._1==2)
printf(">=2 and <3: " + x._2+"\n")
if(x._1==3)
printf(">=3 and <4: " + x._2+"\n")
if(x._1==4)
printf(">=4 " + x._2+"\n")
if(x._1==5)
printf("=5 " + x._2+"\n")
}
}
case class User_mov_rat(UserID: Int, MovieID:Int, Pred_rating: Double)
def print_outputfile(final_predictions_adjusted:RDD[((Int, Int), Double)])={
val writer = new FileWriter(new File("./output.txt" ))
writer.write("UserID,MovieID,Pred_rating\n")
final_predictions_adjusted.collect().foreach(x=>{writer.write(x._1._1+","+x._1._2+","+x._2+"\n")})
writer.close()
}
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setAppName("Prateek_Agrawal_task1").setMaster("local[2]")
val sc = new SparkContext(conf)
// val file = "/Users/echoesofconc/Documents/USC_courses/INF553/ml-latest-small/ratings.csv"
// val test = "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/testing_small.csv"
val file = "/Users/echoesofconc/Documents/USC_courses/INF553/ml-20m/ratings.csv"
val test = "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/testing_20m.csv"
val data = sc.textFile(file, 2).cache()
val data_test = sc.textFile(test, 2).cache()
// Drop Header
// val data_wo_header=dropheader(data).persist()
// val data_test_wo_header=dropheader(data_test).persist()
// Create Traing and testing data of the format (User ID, MovID, Rating, Time)
val data_wo_header=dropheader(data).map(_.split(",")).map(x=>((x(0),x(1)),(x(2),x(3))))
val data_test_wo_header=dropheader(data_test).map(_.split(",")).map(x=>((x(0),x(1)),1))
val ratings_train=data_wo_header.subtractByKey(data_test_wo_header)
val ratings_test=data_wo_header.subtractByKey(ratings_train)
data_test_wo_header.unpersist()
data_wo_header.unpersist()
data.unpersist()
data_test.unpersist()
// val ratings_split = data_wo_header.map(line => line.split(",")).persist()
// data_wo_header.unpersist()
// data.unpersist()
// val ratings_testing = data_test_wo_header.map(line => line.split(",")).collect()
// data_test_wo_header.unpersist()
// data_test.unpersist()
//
// val ratings_train = create_training(ratings_split, ratings_testing).persist()
// val ratings_test=create_testing(ratings_split, ratings_testing)
// ratings_split.unpersist()
// ratings_test.unpersist()
// Create the model using rating_train the training data
val rank = 1
val numIterations = 10
// val model=create_model(ratings_train,rank,numIterations)
//
// model.save(sc, "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/myCollaborativeFilter")
val model = MatrixFactorizationModel.load(sc, "/Users/echoesofconc/Documents/USC_courses/INF553/Prateek_Agrawal_hw3/myCollaborativeFilter")
// Average user,Rating from training
val user_avgrat=ratings_train.map(_ match { case ((user, mov), (rate, temp)) =>(user.toInt, (rate.toDouble,1.0))}).reduceByKey((x,y)=>(x._1 + y._1, x._2 + y._2)).mapValues{ case (sum, count) => (1.0 * sum) / count }
ratings_train.unpersist()
// Predict user_mov ratings
val user_mov = data_test_wo_header.map(_ match { case ((user, mov),temp) =>
(user.toInt,mov.toInt)
})
val predictions =
model.predict(user_mov).map { case Rating(user, mov, rate) =>
((user, mov), rate)
}
// Combine Predictions and unpredicted user,Movies due to them being individual. Going forward we need to improve the accuracy for these predictions
val user_mov_rat=user_mov.map(x=>(x,0.0))
val predictions_unpredicted_combined= predictions.union(user_mov_rat).reduceByKey(_+_).map(x=>(x._1._1,(x._1._2,x._2)))
// Combine average rating and predictions+unpredicted values
val avg_rating_predictions_unpredicted_combined=predictions_unpredicted_combined.join(user_avgrat)
// Generate final predictions RDD
val final_predictions=avg_rating_predictions_unpredicted_combined.map{x=>
var temp=((x._1,x._2._1._1),x._2._2)
if(x._2._1._2==0.0){temp=((x._1,x._2._1._1),x._2._2)}
if(x._2._1._2!=0.0){temp=((x._1,x._2._1._1),x._2._1._2)}
temp
}
// Adjust for ratings above 5.0 and below 0.0
val final_predictions_adjusted=final_predictions.map{x=>
var temp=x
if (x._2>5.0){temp=(x._1,5.0)}
if (x._2<0.0){temp=(x._1,0.0)}
temp
}
// final_predictions_adjusted.count()
val ratesAndPreds_map = ratings_test.map(_ match { case ((user, mov), (rate, temp)) => ((user.toInt,mov.toInt),rate.toDouble)})
val ratesAndPreds=ratesAndPreds_map.join(final_predictions_adjusted)
val MSE = ratesAndPreds.map { case ((user, product), (r1, r2)) =>
val err = (r1 - r2)
err * err
}.mean()
val RMSE=math.sqrt(MSE)
// Print output.txt
print_outputfile(final_predictions_adjusted)
// Print the predictionresults
print_results(final_predictions_adjusted.sortByKey())
print(RMSE+"\n")
}
}