[
https://issues.apache.org/jira/browse/SPARK-14153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15213765#comment-15213765
]
Dulaj Rajitha commented on SPARK-14153:
---------------------------------------
This is the java code I used..
package it.codegen.rnd.ml.test;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.ml.evaluation.RegressionEvaluator;
import org.apache.spark.ml.param.ParamMap;
import org.apache.spark.ml.recommendation.ALS;
import org.apache.spark.ml.recommendation.ALSModel;
import org.apache.spark.ml.tuning.CrossValidator;
import org.apache.spark.ml.tuning.CrossValidatorModel;
import org.apache.spark.ml.tuning.ParamGridBuilder;
import org.apache.spark.sql.DataFrame;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.types.DataTypes;
/**
* @author Dulaj Pathirana - Mar 14, 2016
*/
public class ALSImplicitTest
{
static JavaSparkContext jsc;
final static String sparkMaster = "spark://192.168.1.71:7077";
final static String dataPathPrefix = "hdfs://192.168.1.71/res/";
final static String trainDataFile = dataPathPrefix + "train.csv";
final static String testDataFile = dataPathPrefix + "test.csv";
final static String modelPath = dataPathPrefix + "als_implicit1.model";
final static String sparkLogDir = dataPathPrefix + "logs/";
static DataFrame test;
static DataFrame train;
public static void main( String[] args )
{
final int folds = 2;
final int[] ranks = { 120, 500 };
double alpha = 0.01, regParam = 0.02, tuningInterval = 0.01;
final double[] alphas = prepareDoubleParams( alpha,
tuningInterval, 1 );
final double[] regParams = prepareDoubleParams( regParam,
tuningInterval, 1 );
prepareDataFrames();
// Build the recommendation model using ALS on the training data
// numBlocks is the number of blocks used to parallelize
computation (set to -1 to auto-configure).
// rank is the number of latent factors in the model.
// iterations is the number of iterations to run.
// lambda specifies the regularization parameter in ALS.
// implicitPrefs specifies whether to use the explicit feedback
ALS variant or one adapted for implicit feedback data.
// alpha is a parameter applicable to the implicit feedback
variant of ALS that governs the baseline confidence in preference observations.
ALS implicitALS = new ALS().setImplicitPrefs( true
).setUserCol( "user" ).setItemCol( "item" )
.setRatingCol( "confidence" ).setPredictionCol(
"prediction" );
ParamMap[] paramMaps = new ParamGridBuilder().addGrid(
implicitALS.alpha(), alphas )
.addGrid( implicitALS.regParam(), regParams
).addGrid( implicitALS.rank(), ranks ).build();
RegressionEvaluator evaluator = new
RegressionEvaluator().setMetricName( "rmse" ).setLabelCol( "confidence" )
.setPredictionCol( "prediction" );
CrossValidator crossValidator = new
CrossValidator().setEstimator( implicitALS ).setEvaluator( evaluator )
.setEstimatorParamMaps( paramMaps
).setNumFolds( folds );
CrossValidatorModel crossValidatorModel = crossValidator.fit(
train );
// save model
ALSModel alsModel = ( ALSModel )
crossValidatorModel.bestModel();
alsModel.write().overwrite().saveImpl( modelPath );
// load model
ALSModel bestModel = ALSModel.read().load( modelPath );
// predict
DataFrame predictDf = bestModel.transform( train.randomSplit(
new double[] { 0.8, 0.2 } )[1] );
DataFrame predictions = predictDf
.withColumn( "confidence", predictDf.col(
"confidence" ).cast( DataTypes.DoubleType ) )
.withColumn( "prediction", predictDf.col(
"prediction" ) );
predictDf.show();
System.out.println( "Root-mean-square error = " +
evaluator.evaluate( predictions ) );
jsc.stop();
}
private static void prepareDataFrames()
{
final SparkConf conf = new SparkConf().setAppName( "ALS-Implict
with cross validation Model" )
.setMaster( sparkMaster ).set(
"spark.executor.memory", "4g" ).set( "spark.eventLog.dir", sparkLogDir )
.set( "spark.eventLog.enabled", "false" );
jsc = new JavaSparkContext( conf );
jsc.addJar( dataPathPrefix + "spark-csv_2.10-1.3.0.jar" );
jsc.addJar( dataPathPrefix + "commons-csv-1.2.jar" );
final SQLContext sqlContext = new SQLContext( jsc );
DataFrame tst = sqlContext.read().format(
"com.databricks.spark.csv" ).option( "inferSchema", "true" )
.option( "header", "true" ).load( testDataFile
);
test = tst.withColumn( "confidence", tst.col( "confidence"
).cast( DataTypes.DoubleType ) ).cache();
DataFrame trn = sqlContext.read().format(
"com.databricks.spark.csv" ).option( "inferSchema", "true" )
.option( "header", "true" ).load( trainDataFile
);
train = trn.withColumn( "confidence", trn.col( "confidence"
).cast( DataTypes.DoubleType ) ).cache();
}
private static double[] prepareDoubleParams( double start, double
interval, int steps )
{
double[] res = new double[steps + 1];
res[0] = start;
for ( int i = 1; i <= steps; i++ )
{
res[i] = ( start += interval );
}
return res;
}
}
> My dataset does not provide proper predictions in ALS
> -----------------------------------------------------
>
> Key: SPARK-14153
> URL: https://issues.apache.org/jira/browse/SPARK-14153
> Project: Spark
> Issue Type: Question
> Components: Java API, ML
> Reporter: Dulaj Rajitha
>
> When I used data-set in the git-hub example, I get proper predictions. But
> when I used my data set It does not predict well. (I has a large RMSE).
> I used cross validator for ALS (in Spark ML) and here are the best model
> parameters.
> 16/03/25 12:03:06 INFO CrossValidator: Average cross-validation metrics:
> WrappedArray(NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN)
> 16/03/25 12:03:06 INFO CrossValidator: Best set of parameters:
> {
> als_c911c0e183a3-alpha: 0.02,
> als_c911c0e183a3-rank: 500,
> als_c911c0e183a3-regParam: 0.03
> }
> But when I used movie data set It gives proper values for parameters. as below
> 16/03/24 14:07:07 INFO CrossValidator: Average cross-validation metrics:
> WrappedArray(1.9481584447713676, 2.0501457159728944, 2.0600857505406935,
> 1.9457234533860048, 2.0494498583414282, 2.0595306613827002,
> 1.9488322049918922, 2.0489573853226797, 2.0584252131752, 1.9464006741621391,
> 2.048241271354197, 2.057853990227443)
> 16/03/24 14:07:07 INFO CrossValidator: Best set of parameters:
> {
> als_31a605e7717b-alpha: 0.02,
> als_31a605e7717b-rank: 1,
> als_31a605e7717b-regParam: 0.02
> }
> 16/03/24 14:07:07 INFO CrossValidator: Best cross-validation metric:
> 1.9457234533860048.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
