SOLR-10638: Add normalize Stream Evaluator

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

@@ -172,6 +172,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       .withFunctionName("regress", RegressionEvaluator.class)
       .withFunctionName("cov", CovarianceEvaluator.class)
       .withFunctionName("conv", ConvolutionEvaluator.class)
+      .withFunctionName("normalize", NormalizeEvaluator.class)
 
       // metrics
          .withFunctionName("min", MinMetric.class)

solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/NormalizeEvaluator.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.stream;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.math3.stat.StatUtils;
+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 NormalizeEvaluator extends ComplexEvaluator implements Expressible {
+
+  private static final long serialVersionUID = 1;
+
+  public NormalizeEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
+    super(expression, factory);
+  }
+
+  public List<Number> evaluate(Tuple tuple) throws IOException {
+    StreamEvaluator colEval1 = subEvaluators.get(0);
+
+    List<Number> numbers1 = (List<Number>)colEval1.evaluate(tuple);
+    double[] column1 = new double[numbers1.size()];
+
+    for(int i=0; i<numbers1.size(); i++) {
+      column1[i] = numbers1.get(i).doubleValue();
+    }
+
+    double[] normalized = StatUtils.normalize(column1);
+
+    List<Number> normalizeList = new ArrayList(normalized.length);
+    for(double d : normalized) {
+      normalizeList.add(d);
+    }
+
+    return normalizeList;
+  }
+
+  @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

@@ -570,7 +570,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
         .add(id, "0", "a_i", "1", "a_f", "0", "s_multi", "aaa", "s_multi", "bbb", "i_multi", "100", "i_multi", "200")
         .add(id, "2", "a_s", "hello2", "a_i", "3", "a_f", "0")
         .add(id, "3", "a_s", "hello3", "a_i", "4", "a_f", "3")
-        .add(id, "4", "a_s", "hello4",             "a_f", "4")
+        .add(id, "4", "a_s", "hello4", "a_f", "4")
         .add(id, "1", "a_s", "hello1", "a_i", "2", "a_f", "1")
         .commit(cluster.getSolrClient(), COLLECTIONORALIAS);
 
@@ -4049,7 +4049,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
         false, true, TIMEOUT);
 
     new UpdateRequest()
-        .add(id, "0", "a_s", "hello0", "a_i", "0", "a_f", "0", "s_multi", "aaaa",  "s_multi", "bbbb",  "i_multi", "4", "i_multi", "7")
+        .add(id, "0", "a_s", "hello0", "a_i", "0", "a_f", "0", "s_multi", "aaaa", "s_multi", "bbbb", "i_multi", "4", "i_multi", "7")
         .add(id, "2", "a_s", "hello2", "a_i", "2", "a_f", "0", "s_multi", "aaaa1", "s_multi", "bbbb1", "i_multi", "44", "i_multi", "77")
         .add(id, "3", "a_s", "hello3", "a_i", "3", "a_f", "3", "s_multi", "aaaa2", "s_multi", "bbbb2", "i_multi", "444", "i_multi", "777")
         .add(id, "4", "a_s", "hello4", "a_i", "4", "a_f", "4", "s_multi", "aaaa3", "s_multi", "bbbb3", "i_multi", "4444", "i_multi", "7777")
@@ -5401,6 +5401,59 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     assertTrue(prediction == 600.0D);
   }
 
+  @Test
+  public void testNormalize() throws Exception {
+    UpdateRequest updateRequest = new UpdateRequest();
+
+    updateRequest.add(id, "1", "price_f", "100.0", "col_s", "a", "order_i", "1");
+    updateRequest.add(id, "2", "price_f", "200.0", "col_s", "a", "order_i", "2");
+    updateRequest.add(id, "3", "price_f", "300.0", "col_s", "a", "order_i", "3");
+    updateRequest.add(id, "4", "price_f", "100.0", "col_s", "a", "order_i", "4");
+    updateRequest.add(id, "5", "price_f", "200.0", "col_s", "a", "order_i", "5");
+    updateRequest.add(id, "6", "price_f", "400.0", "col_s", "a", "order_i", "6");
+    updateRequest.add(id, "7", "price_f", "600.0", "col_s", "a", "order_i", "7");
+
+    updateRequest.commit(cluster.getSolrClient(), COLLECTIONORALIAS);
+
+    String expr1 = "search("+COLLECTIONORALIAS+", q=\"col_s:a\", fl=\"price_f, order_i\", sort=\"order_i asc\")";
+    String cexpr = "let(a="+expr1+", c=col(a, price_f), tuple(n=normalize(c), c=c))";
+
+    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);
+    Tuple tuple = tuples.get(0);
+    List<Double> col = (List<Double>)tuple.get("c");
+    List<Double> normalized = (List<Double>)tuple.get("n");
+
+    assertTrue(col.size() == normalized.size());
+
+    double total = 0.0D;
+
+    for(double d : normalized) {
+      total += d;
+    }
+
+    double mean = total/normalized.size();
+    assert(Math.round(mean) == 0);
+
+    double sd = 0;
+    for (int i = 0; i < normalized.size(); i++)
+    {
+      sd += Math.pow(normalized.get(i) - mean, 2) / normalized.size();
+    }
+    double standardDeviation = Math.sqrt(sd);
+
+    assertTrue(Math.round(standardDeviation) == 1);
+  }
+
   @Test
   public void testListStream() throws Exception {
     UpdateRequest updateRequest = new UpdateRequest();
@@ -5717,7 +5770,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     cluster.getSolrClient().commit("destination");
     paramsLoc = new ModifiableSolrParams();
     paramsLoc.set("expr", "search(destination, q=\"*:*\", fl=\"id, body_t, field_i\", rows=1000, sort=\"field_i asc\")");
-    paramsLoc.set("qt","/stream");
+    paramsLoc.set("qt", "/stream");
 
     SolrStream solrStream = new SolrStream(url, paramsLoc);
     List<Tuple> tuples = getTuples(solrStream);