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From: erans@apache.org
To: commits@commons.apache.org
Date: Tue, 09 Aug 2016 20:48:34 -0000
Message-Id: <e1a78ae6f36c445f8e98abad243216b9@git.apache.org>
In-Reply-To: <8965984aedbe41df858068a058923989@git.apache.org>
References: <8965984aedbe41df858068a058923989@git.apache.org>
Subject: [2/2] commons-rng git commit: Benchmarking code example.
archived-at: Tue, 09 Aug 2016 20:48:35 -0000

Benchmarking code example.

Thanks to Artem Barger.
Committed with some modifications.


Project: http://git-wip-us.apache.org/repos/asf/commons-rng/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-rng/commit/05f49b3d
Tree: http://git-wip-us.apache.org/repos/asf/commons-rng/tree/05f49b3d
Diff: http://git-wip-us.apache.org/repos/asf/commons-rng/diff/05f49b3d

Branch: refs/heads/master
Commit: 05f49b3d6580aee3ace055fa379c6e1a705e07b9
Parents: 883b17f
Author: Gilles <erans@apache.org>
Authored: Tue Aug 9 22:46:54 2016 +0200
Committer: Gilles <erans@apache.org>
Committed: Tue Aug 9 22:46:54 2016 +0200

----------------------------------------------------------------------
 .../commons/rng/ComputePiTestPerformance.java   | 97 ++++++++++++++++++++
 1 file changed, 97 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-rng/blob/05f49b3d/src/test/java/org/apache/commons/rng/ComputePiTestPerformance.java
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diff --git a/src/test/java/org/apache/commons/rng/ComputePiTestPerformance.java b/src/test/java/org/apache/commons/rng/ComputePiTestPerformance.java
new file mode 100644
index 0000000..ce5e47e
--- /dev/null
+++ b/src/test/java/org/apache/commons/rng/ComputePiTestPerformance.java
@@ -0,0 +1,97 @@
+/*
+ * 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.rng;
+
+import org.openjdk.jmh.annotations.*;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Benchmark that compares the performance of the RNG implementations
+ * by running a simple workload: computation of \( \pi \).
+ *
+ * The computation estimates the value by computing the probability that
+ * a point p=(x, y) will lie in the circle of radius \( r = 1 \) inscribed
+ * in the square.
+ * The probability could be computed by \[ area_{circle} / area_{square} \],
+ * where \( area_{circle} = \pi * r^2 \) and \( area_{square} = 4 r^2 \).
+ * Hence, the probability is \( \frac{\pi}{4} \).
+ *
+ * The Monte Carlo simulation will produce \( N \) points.
+ * Defining \( N_c \) as the number of point that satisfy \( x^2 + y^2 <= 1 \),
+ * we will have \( \frac{N_c}{N} \approx \frac{\pi}{4} \).
+ */
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(1)
+public class ComputePiTestPerformance {
+    /**
+     * The benchmark state (retrieve the various "RandomSource"s).
+     */
+    @State(Scope.Benchmark)
+    public static class Sources {
+        /**
+         * RNG providers.
+         */
+        @Param({"JDK",
+                "WELL_512_A",
+                "WELL_1024_A",
+                "WELL_19937_A",
+                "WELL_19937_C",
+                "WELL_44497_A",
+                "WELL_44497_B",
+                "MT",
+                "ISAAC",
+                "SPLIT_MIX_64",
+                "XOR_SHIFT_1024_S",
+                "TWO_CMRES",
+                "MT_64" })
+                String randomSourceName;
+
+        /**
+         * Number of 2D-points to generate.
+         */
+        @Param({"1000000"})
+        long numPoints;
+        
+        UniformRandomProvider provider;
+
+        @Setup
+        public void setup() {
+            final RandomSource randomSource = RandomSource.valueOf(randomSourceName);
+            provider = RandomSource.create(randomSource);
+        }
+    }
+
+    @Benchmark
+    public double computePi(Sources data) {
+        long numPointsInCircle = 0;
+        for (int i = 0; i < data.numPoints; i++) {
+            final double x = data.provider.nextDouble();
+            final double y = data.provider.nextDouble();
+            final double r2 = x * x + y * y;
+            if (r2 <= 1) {
+                ++numPointsInCircle;
+            }
+        }
+
+        final double pi = 4 * numPointsInCircle / (double) data.numPoints;
+        // System.out.println("pi=" + pi);
+        return pi;
+    }
+}