SOLR-11338: Add Kendall's Tau-b rank and Spearmans rank correlation Stream Evaluators

solr/core/src/java/org/apache/solr/handler/StreamHandler.java

@@ -250,6 +250,8 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
         .withFunctionName("copyOf", CopyOfEvaluator.class)
         .withFunctionName("cov", CovarianceEvaluator.class)
         .withFunctionName("corr", CorrelationEvaluator.class)
+        .withFunctionName("kendallsCorr", KendallsCorrelationEvaluator.class)
+        .withFunctionName("spearmansCorr", SpearmansCorrelationEvaluator.class)
         .withFunctionName("describe", DescribeEvaluator.class)
         .withFunctionName("distance", EuclideanDistanceEvaluator.class)
         .withFunctionName("empiricalDistribution", EmpiricalDistributionEvaluator.class)

solr/solrj/src/java/org/apache/solr/client/solrj/io/eval/KendallsCorrelationEvaluator.java

@@ -0,0 +1,57 @@
+/*
+ * 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.eval;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Locale;
+
+import org.apache.commons.math3.stat.correlation.KendallsCorrelation;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
+import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
+
+public class KendallsCorrelationEvaluator extends RecursiveNumericEvaluator implements TwoValueWorker {
+  protected static final long serialVersionUID = 1L;
+
+  public KendallsCorrelationEvaluator(StreamExpression expression, StreamFactory factory) throws IOException{
+    super(expression, factory);
+  }
+
+  @Override
+  public Object doWork(Object first, Object second) throws IOException{
+    if(null == first){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the first value",toExpression(constructingFactory)));
+    }
+    if(null == second){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the second value",toExpression(constructingFactory)));
+    }
+    if(!(first instanceof List<?>)){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the first value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName()));
+    }
+    if(!(second instanceof List<?>)){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the second value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName()));
+    }
+
+    KendallsCorrelation kendallsCorrelation = new KendallsCorrelation();
+
+    return kendallsCorrelation.correlation(
+        ((List)first).stream().mapToDouble(value -> ((BigDecimal)value).doubleValue()).toArray(),
+        ((List)second).stream().mapToDouble(value -> ((BigDecimal)value).doubleValue()).toArray()
+    );
+  }
+}

solr/solrj/src/java/org/apache/solr/client/solrj/io/eval/SpearmansCorrelationEvaluator.java

@@ -0,0 +1,57 @@
+/*
+ * 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.eval;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Locale;
+
+import org.apache.commons.math3.stat.correlation.SpearmansCorrelation;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
+import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
+
+public class SpearmansCorrelationEvaluator extends RecursiveNumericEvaluator implements TwoValueWorker {
+  protected static final long serialVersionUID = 1L;
+
+  public SpearmansCorrelationEvaluator(StreamExpression expression, StreamFactory factory) throws IOException{
+    super(expression, factory);
+  }
+
+  @Override
+  public Object doWork(Object first, Object second) throws IOException{
+    if(null == first){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the first value",toExpression(constructingFactory)));
+    }
+    if(null == second){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the second value",toExpression(constructingFactory)));
+    }
+    if(!(first instanceof List<?>)){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the first value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName()));
+    }
+    if(!(second instanceof List<?>)){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the second value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName()));
+    }
+
+    SpearmansCorrelation spearmansCorrelation = new SpearmansCorrelation();
+
+    return spearmansCorrelation.correlation(
+        ((List)first).stream().mapToDouble(value -> ((BigDecimal)value).doubleValue()).toArray(),
+        ((List)second).stream().mapToDouble(value -> ((BigDecimal)value).doubleValue()).toArray()
+    );
+  }
+}

solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java

@@ -5514,7 +5514,8 @@ public class StreamExpressionTest extends SolrCloudTestCase {
         "field=\"test_dt\", " +
         "count(*), sum(price_f), max(price_f), min(price_f))";
 
-    String cexpr = "let(a="+expr+", b=select("+expr+",mult(-1, count(*)) as nvalue), c=col(a, count(*)), d=col(b, nvalue), tuple(corr=corr(c,d)))";
+    String cexpr = "let(a="+expr+", b=select("+expr+",mult(-1, count(*)) as nvalue), c=col(a, count(*)), d=col(b, nvalue), " +
+                       "tuple(corr=corr(c,d), scorr=spearmansCorr(array(500, 50, 50, 50),d), kcorr=kendallsCorr(array(500, 50, 50, 50),d), d=d))";
 
     ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
     paramsLoc.set("expr", cexpr);
@@ -5528,6 +5529,8 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     List<Tuple> tuples = getTuples(solrStream);
     assertTrue(tuples.size() == 1);
     assertTrue(tuples.get(0).getDouble("corr").equals(-1.0D));
+    assertTrue(tuples.get(0).getDouble("scorr").equals(-1.0D));
+    assertTrue(tuples.get(0).getDouble("kcorr").equals(-1.0D));
   }