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Posted to commits@commons.apache.org by lu...@apache.org on 2016/01/17 11:42:01 UTC
[12/22] [math] Reverting commit
8a35ca4f8e19b914a8503d1d5156212363cbaf10 as per Gilles request.
Reverting commit 8a35ca4f8e19b914a8503d1d5156212363cbaf10 as per Gilles request.
The work on revamping the random packages is perfoemd in the random-ravamp branch.
Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/e0a8ac4f
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/e0a8ac4f
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/e0a8ac4f
Branch: refs/heads/master
Commit: e0a8ac4fb5891e6760f7238027dcbb3e23e23054
Parents: 16f46dc
Author: Luc Maisonobe <lu...@apache.org>
Authored: Sun Jan 17 11:35:24 2016 +0100
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Sun Jan 17 11:40:27 2016 +0100
----------------------------------------------------------------------
.../math4/random/AbstractRandomGenerator.java | 294 +++++++++++++++++++
.../random/AbstractRandomGeneratorTest.java | 39 +++
.../math4/random/TestRandomGenerator.java | 43 +++
3 files changed, 376 insertions(+)
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http://git-wip-us.apache.org/repos/asf/commons-math/blob/e0a8ac4f/src/main/java/org/apache/commons/math4/random/AbstractRandomGenerator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math4/random/AbstractRandomGenerator.java b/src/main/java/org/apache/commons/math4/random/AbstractRandomGenerator.java
new file mode 100644
index 0000000..2115dbd
--- /dev/null
+++ b/src/main/java/org/apache/commons/math4/random/AbstractRandomGenerator.java
@@ -0,0 +1,294 @@
+/*
+ * 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.math4.random;
+
+import org.apache.commons.math4.exception.NotStrictlyPositiveException;
+import org.apache.commons.math4.util.FastMath;
+
+/**
+ * Abstract class implementing the {@link RandomGenerator} interface.
+ * Default implementations for all methods other than {@link #nextDouble()} and
+ * {@link #setSeed(long)} are provided.
+ * <p>
+ * All data generation methods are based on {@code code nextDouble()}.
+ * Concrete implementations <strong>must</strong> override
+ * this method and <strong>should</strong> provide better / more
+ * performant implementations of the other methods if the underlying PRNG
+ * supplies them.</p>
+ *
+ * @since 1.1
+ */
+public abstract class AbstractRandomGenerator implements RandomGenerator {
+
+ /**
+ * Cached random normal value. The default implementation for
+ * {@link #nextGaussian} generates pairs of values and this field caches the
+ * second value so that the full algorithm is not executed for every
+ * activation. The value {@code Double.NaN} signals that there is
+ * no cached value. Use {@link #clear} to clear the cached value.
+ */
+ private double cachedNormalDeviate = Double.NaN;
+
+ /**
+ * Construct a RandomGenerator.
+ */
+ public AbstractRandomGenerator() {
+ super();
+
+ }
+
+ /**
+ * Clears the cache used by the default implementation of
+ * {@link #nextGaussian}. Implementations that do not override the
+ * default implementation of {@code nextGaussian} should call this
+ * method in the implementation of {@link #setSeed(long)}
+ */
+ public void clear() {
+ cachedNormalDeviate = Double.NaN;
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public void setSeed(int seed) {
+ setSeed((long) seed);
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public void setSeed(int[] seed) {
+ // the following number is the largest prime that fits in 32 bits (it is 2^32 - 5)
+ final long prime = 4294967291l;
+
+ long combined = 0l;
+ for (int s : seed) {
+ combined = combined * prime + s;
+ }
+ setSeed(combined);
+ }
+
+ /**
+ * Sets the seed of the underlying random number generator using a
+ * {@code long} seed. Sequences of values generated starting with the
+ * same seeds should be identical.
+ * <p>
+ * Implementations that do not override the default implementation of
+ * {@code nextGaussian} should include a call to {@link #clear} in the
+ * implementation of this method.</p>
+ *
+ * @param seed the seed value
+ */
+ @Override
+ public abstract void setSeed(long seed);
+
+ /**
+ * Generates random bytes and places them into a user-supplied
+ * byte array. The number of random bytes produced is equal to
+ * the length of the byte array.
+ * <p>
+ * The default implementation fills the array with bytes extracted from
+ * random integers generated using {@link #nextInt}.</p>
+ *
+ * @param bytes the non-null byte array in which to put the
+ * random bytes
+ */
+ @Override
+ public void nextBytes(byte[] bytes) {
+ // Multiple 4 part of length (i.e. length with two least significant bits unset).
+ final int max = bytes.length & 0x7ffffffc;
+
+ int index = 0;
+ // Start filling in the byte array, 4 bytes at a time.
+ while (index < max) {
+ final int random = nextInt();
+ bytes[index++] = (byte) random;
+ bytes[index++] = (byte) (random >>> 8);
+ bytes[index++] = (byte) (random >>> 16);
+ bytes[index++] = (byte) (random >>> 24);
+ }
+
+ // Fill in the remaining bytes.
+ if (index < bytes.length) {
+ int random = nextInt();
+ while (true) {
+ bytes[index++] = (byte) random;
+ if (index < bytes.length) {
+ random >>>= 8;
+ } else {
+ break;
+ }
+ }
+ }
+ }
+
+ /**
+ * Returns the next pseudorandom, uniformly distributed {@code int}
+ * value from this random number generator's sequence.
+ * All 2<font size="-1"><sup>32</sup></font> possible {@code int} values
+ * should be produced with (approximately) equal probability.
+ * <p>
+ * The default implementation provided here returns
+ * <pre>
+ * <code>(int) (nextDouble() * Integer.MAX_VALUE)</code>
+ * </pre></p>
+ *
+ * @return the next pseudorandom, uniformly distributed {@code int}
+ * value from this random number generator's sequence
+ */
+ @Override
+ public int nextInt() {
+ return (int) ((2d * nextDouble() - 1d) * Integer.MAX_VALUE);
+ }
+
+ /**
+ * Returns a pseudorandom, uniformly distributed {@code int} value
+ * between 0 (inclusive) and the specified value (exclusive), drawn from
+ * this random number generator's sequence.
+ * <p>
+ * The default implementation returns
+ * <pre>
+ * <code>(int) (nextDouble() * n</code>
+ * </pre></p>
+ *
+ * @param n the bound on the random number to be returned. Must be
+ * positive.
+ * @return a pseudorandom, uniformly distributed {@code int}
+ * value between 0 (inclusive) and n (exclusive).
+ * @throws NotStrictlyPositiveException if {@code n <= 0}.
+ */
+ @Override
+ public int nextInt(int n) {
+ if (n <= 0 ) {
+ throw new NotStrictlyPositiveException(n);
+ }
+ int result = (int) (nextDouble() * n);
+ return result < n ? result : n - 1;
+ }
+
+ /**
+ * Returns the next pseudorandom, uniformly distributed {@code long}
+ * value from this random number generator's sequence. All
+ * 2<font size="-1"><sup>64</sup></font> possible {@code long} values
+ * should be produced with (approximately) equal probability.
+ * <p>
+ * The default implementation returns
+ * <pre>
+ * <code>(long) (nextDouble() * Long.MAX_VALUE)</code>
+ * </pre></p>
+ *
+ * @return the next pseudorandom, uniformly distributed {@code long}
+ *value from this random number generator's sequence
+ */
+ @Override
+ public long nextLong() {
+ return (long) ((2d * nextDouble() - 1d) * Long.MAX_VALUE);
+ }
+
+ /**
+ * Returns the next pseudorandom, uniformly distributed
+ * {@code boolean} value from this random number generator's
+ * sequence.
+ * <p>
+ * The default implementation returns
+ * <pre>
+ * <code>nextDouble() <= 0.5</code>
+ * </pre></p>
+ *
+ * @return the next pseudorandom, uniformly distributed
+ * {@code boolean} value from this random number generator's
+ * sequence
+ */
+ @Override
+ public boolean nextBoolean() {
+ return nextDouble() <= 0.5;
+ }
+
+ /**
+ * Returns the next pseudorandom, uniformly distributed {@code float}
+ * value between {@code 0.0} and {@code 1.0} from this random
+ * number generator's sequence.
+ * <p>
+ * The default implementation returns
+ * <pre>
+ * <code>(float) nextDouble() </code>
+ * </pre></p>
+ *
+ * @return the next pseudorandom, uniformly distributed {@code float}
+ * value between {@code 0.0} and {@code 1.0} from this
+ * random number generator's sequence
+ */
+ @Override
+ public float nextFloat() {
+ return (float) nextDouble();
+ }
+
+ /**
+ * Returns the next pseudorandom, uniformly distributed
+ * {@code double} value between {@code 0.0} and
+ * {@code 1.0} from this random number generator's sequence.
+ * <p>
+ * This method provides the underlying source of random data used by the
+ * other methods.</p>
+ *
+ * @return the next pseudorandom, uniformly distributed
+ * {@code double} value between {@code 0.0} and
+ * {@code 1.0} from this random number generator's sequence
+ */
+ @Override
+ public abstract double nextDouble();
+
+ /**
+ * Returns the next pseudorandom, Gaussian ("normally") distributed
+ * {@code double} value with mean {@code 0.0} and standard
+ * deviation {@code 1.0} from this random number generator's sequence.
+ * <p>
+ * The default implementation uses the <em>Polar Method</em>
+ * due to G.E.P. Box, M.E. Muller and G. Marsaglia, as described in
+ * D. Knuth, <u>The Art of Computer Programming</u>, 3.4.1C.</p>
+ * <p>
+ * The algorithm generates a pair of independent random values. One of
+ * these is cached for reuse, so the full algorithm is not executed on each
+ * activation. Implementations that do not override this method should
+ * make sure to call {@link #clear} to clear the cached value in the
+ * implementation of {@link #setSeed(long)}.</p>
+ *
+ * @return the next pseudorandom, Gaussian ("normally") distributed
+ * {@code double} value with mean {@code 0.0} and
+ * standard deviation {@code 1.0} from this random number
+ * generator's sequence
+ */
+ @Override
+ public double nextGaussian() {
+ if (!Double.isNaN(cachedNormalDeviate)) {
+ double dev = cachedNormalDeviate;
+ cachedNormalDeviate = Double.NaN;
+ return dev;
+ }
+ double v1 = 0;
+ double v2 = 0;
+ double s = 1;
+ while (s >=1 ) {
+ v1 = 2 * nextDouble() - 1;
+ v2 = 2 * nextDouble() - 1;
+ s = v1 * v1 + v2 * v2;
+ }
+ if (s != 0) {
+ s = FastMath.sqrt(-2 * FastMath.log(s) / s);
+ }
+ cachedNormalDeviate = v2 * s;
+ return v1 * s;
+ }
+}
http://git-wip-us.apache.org/repos/asf/commons-math/blob/e0a8ac4f/src/test/java/org/apache/commons/math4/random/AbstractRandomGeneratorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math4/random/AbstractRandomGeneratorTest.java b/src/test/java/org/apache/commons/math4/random/AbstractRandomGeneratorTest.java
new file mode 100644
index 0000000..79cf97d
--- /dev/null
+++ b/src/test/java/org/apache/commons/math4/random/AbstractRandomGeneratorTest.java
@@ -0,0 +1,39 @@
+/*
+ * 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.math4.random;
+
+import org.apache.commons.math4.random.RandomGenerator;
+
+/**
+ * Test cases for the AbstractRandomGenerator class.
+ *
+ */
+
+public class AbstractRandomGeneratorTest extends RandomGeneratorAbstractTest {
+
+ public AbstractRandomGeneratorTest() {
+ super();
+ }
+
+ @Override
+ protected RandomGenerator makeGenerator() {
+ RandomGenerator generator = new TestRandomGenerator();
+ generator.setSeed(1001);
+ return generator;
+ }
+
+}
http://git-wip-us.apache.org/repos/asf/commons-math/blob/e0a8ac4f/src/test/java/org/apache/commons/math4/random/TestRandomGenerator.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math4/random/TestRandomGenerator.java b/src/test/java/org/apache/commons/math4/random/TestRandomGenerator.java
new file mode 100644
index 0000000..fc820b2
--- /dev/null
+++ b/src/test/java/org/apache/commons/math4/random/TestRandomGenerator.java
@@ -0,0 +1,43 @@
+/*
+ * 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.math4.random;
+import java.util.Random;
+
+import org.apache.commons.math4.random.AbstractRandomGenerator;
+
+/**
+ * Dummy AbstractRandomGenerator concrete subclass that just wraps a
+ * java.util.Random instance. Used by AbstractRandomGeneratorTest to test
+ * default implementations in AbstractRandomGenerator.
+ *
+ */
+public class TestRandomGenerator extends AbstractRandomGenerator {
+
+ private Random random = new Random();
+
+ @Override
+ public void setSeed(long seed) {
+ clear();
+ random.setSeed(seed);
+ }
+
+ @Override
+ public double nextDouble() {
+ return random.nextDouble();
+ }
+
+}