/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.solr.client.solrj.io.stream;
import java.io.IOException;
import java.util.List;
import org.apache.commons.math3.stat.correlation.PearsonsCorrelation;
import org.apache.solr.client.solrj.io.Tuple;
import org.apache.solr.client.solrj.io.eval.ComplexEvaluator;
import org.apache.solr.client.solrj.io.eval.StreamEvaluator;
import org.apache.solr.client.solrj.io.stream.expr.Explanation;
import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType;
import org.apache.solr.client.solrj.io.stream.expr.Expressible;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParameter;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
public class CorrelationEvaluator extends ComplexEvaluator implements Expressible {
private static final long serialVersionUID = 1;
public CorrelationEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
super(expression, factory);
}
public Number evaluate(Tuple tuple) throws IOException {
StreamEvaluator colEval1 = subEvaluators.get(0);
StreamEvaluator colEval2 = subEvaluators.get(1);
List<Number> numbers1 = (List<Number>)colEval1.evaluate(tuple);
List<Number> numbers2 = (List<Number>)colEval2.evaluate(tuple);
double[] column1 = new double[numbers1.size()];
double[] column2 = new double[numbers2.size()];
for(int i=0; i<numbers1.size(); i++) {
column1[i] = numbers1.get(i).doubleValue();
}
for(int i=0; i<numbers2.size(); i++) {
column2[i] = numbers2.get(i).doubleValue();
}
PearsonsCorrelation pearsonsCorrelation = new PearsonsCorrelation();
return pearsonsCorrelation.correlation(column1, column2);
}
@Override
public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException {
StreamExpression expression = new StreamExpression(factory.getFunctionName(getClass()));
return expression;
}
@Override
public Explanation toExplanation(StreamFactory factory) throws IOException {
return new Explanation(nodeId.toString())
.withExpressionType(ExpressionType.EVALUATOR)
.withFunctionName(factory.getFunctionName(getClass()))
.withImplementingClass(getClass().getName())
.withExpression(toExpression(factory).toString());
}
}