MATH-637

Simple benchmarking utility.


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1152380 13f79535-47bb-0310-9956-ffa450edef68

src/site/xdoc/changes.xml

@@ -52,6 +52,9 @@ The <action> type attribute can be add,update,fix,remove.
     If the output is not quite correct, check for invisible trailing spaces!
      -->
     <release version="3.0" date="TBD" description="TBD">
+      <action dev="erans" type="add" issue="MATH-637">
+        Simple benchmark utility (new class "PerfTestUtils").
+      </action>
       <action dev="luc" type="add" issue="MATH-636" >
         Added a solver for Dfp-based (i.e. high accuracy) functions.
       </action>

src/test/java/org/apache/commons/math/PerfTestUtils.java

@@ -0,0 +1,115 @@
+/*
+ * 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.commons.math;
+
+import org.apache.commons.math.analysis.function.Add;
+import org.apache.commons.math.analysis.MultivariateRealFunction;
+import org.apache.commons.math.analysis.FunctionUtils;
+
+/**
+ * Simple benchmarking utilities.
+ */
+public class PerfTestUtils {
+    /** Nanoseconds to milliseconds conversion factor ({@value}). */
+    public static final double NANO_TO_MILLI = 1e-6;
+
+    /**
+     * Timing.
+     *
+     * @param repeatChunk Each timing measurement will done done for that
+     * number of repeats of the code.
+     * @param repeatStat Timing will be averaged over that number of runs. 
+     * @param methods Code being timed.
+     * @return for each of the given {@code methods}, the averaged time (in
+     * milliseconds) taken by a call to {@code run}.
+     */
+    public static double[] time(int repeatChunk,
+                                int repeatStat,
+                                Runnable ... methods) {
+        final int numMethods = methods.length;
+        final double[][] times = new double[numMethods][repeatStat];
+    
+        for (int k = 0; k < repeatStat; k++) {
+            for (int j = 0; j < numMethods; j++) {
+                final Runnable r = methods[j];
+                final long start = System.nanoTime();
+                for (int i = 0; i < repeatChunk; i++) {
+                    r.run();
+                }
+                times[j][k] = (System.nanoTime() - start) * NANO_TO_MILLI;
+            }
+        }
+
+        final MultivariateRealFunction acc = FunctionUtils.collector(new Add(), 0);
+        final double[] avgTimes = new double[numMethods];
+
+        final double normFactor = 1d / (repeatStat * repeatChunk);
+        for (int j = 0; j < numMethods; j++) {
+            avgTimes[j] = normFactor * acc.value(times[j]);
+        }
+
+        return avgTimes;
+    }
+
+    /**
+     * Timing and report (to standard output).
+     *
+     * @param title Title of the test (for the report).
+     * @param repeatChunk Each timing measurement will done done for that
+     * number of repeats of the code.
+     * @param repeatStat Timing will be averaged over that number of runs. 
+     * @param methods Code being timed.
+     * @return for each of the given {@code methods}, the averaged time (in
+     * milliseconds) taken by a call to {@code run}.
+     */
+    public static double[] timeAndReport(String title,
+                                         int repeatChunk,
+                                         int repeatStat,
+                                         RunTest ... methods) {
+        System.out.println(title);
+        final double[] time = time(repeatChunk, repeatStat, methods);
+        for (int i = 0; i < time.length; i++) {
+            System.out.println(methods[i].getName() + ": " + time[i] + " ms");
+        }
+
+        return time;
+    }
+
+    /**
+     * Utility class for storing a test label.
+     */
+    public static abstract class RunTest implements Runnable {
+        private final String name;
+
+        /**
+         * @param name Test name.
+         */
+        public RunTest(String name) {
+            this.name = name;
+        }
+
+        /**
+         * @return the name of this test.
+         */
+        public String getName() {
+            return name;
+        }
+
+        /** {@inheritDoc} */
+        public abstract void run();
+    }
+}