SOLR-10765: Add anova Stream Evaluator

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

@@ -192,6 +192,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       .withFunctionName("sequence", SequenceEvaluator.class)
       .withFunctionName("array", ArrayEvaluator.class)
       .withFunctionName("hist", HistogramEvaluator.class)
+      .withFunctionName("anova", AnovaEvaluator.class)
 
       // metrics
          .withFunctionName("min", MinMetric.class)

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

@@ -0,0 +1,76 @@
+/*
+ * 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.util.ArrayList;
+import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.math3.stat.inference.OneWayAnova;
+import org.apache.solr.client.solrj.io.Tuple;
+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 AnovaEvaluator extends ComplexEvaluator implements Expressible {
+
+  private static final long serialVersionUID = 1;
+
+  public AnovaEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
+    super(expression, factory);
+  }
+
+  public Tuple evaluate(Tuple tuple) throws IOException {
+    List<double[]> list = new ArrayList();
+    for(StreamEvaluator subEvaluator : subEvaluators) {
+      List<Number> nums = (List<Number>)subEvaluator.evaluate(tuple);
+      double[] darray = new double[nums.size()];
+      for(int i=0; i< nums.size(); i++) {
+        darray[i]=nums.get(i).doubleValue();
+      }
+      list.add(darray);
+    }
+
+    OneWayAnova anova = new OneWayAnova();
+    double p = anova.anovaPValue(list);
+    double f = anova.anovaFValue(list);
+    Map m = new HashMap();
+    m.put("p-value", p);
+    m.put("f-ratio", f);
+    return new Tuple(m);
+  }
+
+  @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());
+  }
+}

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

@@ -5821,6 +5821,24 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     assertTrue(out.get(5).doubleValue() == 500.23D);
   }
 
+  @Test
+  public void testAnova() throws Exception {
+    String cexpr = "anova(array(1,2,3,5,4,6), array(5,2,3,5,4,6), array(1,2,7,5,4,6))";
+    ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", cexpr);
+    paramsLoc.set("qt", "/stream");
+    String url = cluster.getJettySolrRunners().get(0).getBaseUrl().toString()+"/"+COLLECTIONORALIAS;
+    TupleStream solrStream = new SolrStream(url, paramsLoc);
+    StreamContext context = new StreamContext();
+    solrStream.setStreamContext(context);
+    List<Tuple> tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    Map out = (Map)tuples.get(0).get("return-value");
+    assertEquals((double)out.get("p-value"), 0.788298D, .0001);
+    assertEquals((double)out.get("f-ratio"), 0.24169D, .0001);
+  }
+
+
   @Test
   public void testScale() throws Exception {
     UpdateRequest updateRequest = new UpdateRequest();