--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/random/MRG32k3a.java Thu Jun 27 18:02:51 2019 -0300
@@ -0,0 +1,472 @@
+/*
+ * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.util;
+
+import java.math.BigInteger;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * A generator of uniform pseudorandom values applicable for use in
+ * (among other contexts) isolated parallel computations that may
+ * generate subtasks. Class {@code MRG32k3a} implements
+ * interfaces {@link java.util.Rng} and {@link java.util.AbstractArbitrarilyJumpableRng},
+ * and therefore supports methods for producing pseudorandomly chosen
+ * numbers of type {@code int}, {@code long}, {@code float}, and {@code double}
+ * as well as creating new {@code Xoroshiro128PlusMRG32k3a} objects
+ * by "jumping" or "leaping".
+ *
+ * <p>Instances {@code Xoroshiro128Plus} are <em>not</em> thread-safe.
+ * They are designed to be used so that each thread as its own instance.
+ * The methods {@link #jump} and {@link #leap} and {@link #jumps} and {@link #leaps}
+ * can be used to construct new instances of {@code Xoroshiro128Plus} that traverse
+ * other parts of the state cycle.
+ *
+ * <p>Instances of {@code MRG32k3a} are not cryptographically
+ * secure. Consider instead using {@link java.security.SecureRandom}
+ * in security-sensitive applications. Additionally,
+ * default-constructed instances do not use a cryptographically random
+ * seed unless the {@linkplain System#getProperty system property}
+ * {@code java.util.secureRandomSeed} is set to {@code true}.
+ *
+ * @author Guy Steele
+ * @since 1.9
+ */
+public final class MRG32k3a extends AbstractArbitrarilyJumpableRng {
+
+ /*
+ * Implementation Overview.
+ *
+ * See http://simul.iro.umontreal.ca/rng/MRG32k3a.c .
+ *
+ * File organization: First the non-public methods that constitute
+ * the main algorithm, then the main public methods, followed by
+ * some custom spliterator classes needed for stream methods.
+ */
+
+ private final static double norm1 = 2.328306549295728e-10;
+ private final static double norm2 = 2.328318824698632e-10;
+ private final static double m1 = 4294967087.0;
+ private final static double m2 = 4294944443.0;
+ private final static double a12 = 1403580.0;
+ private final static double a13n = 810728.0;
+ private final static double a21 = 527612.0;
+ private final static double a23n = 1370589.0;
+ private final static int m1_deficit = 209;
+
+ // IllegalArgumentException messages
+ private static final String BadLogDistance = "logDistance must be non-negative and not greater than 192";
+
+ /**
+ * The per-instance state.
+ The seeds for s10, s11, s12 must be integers in [0, m1 - 1] and not all 0.
+ The seeds for s20, s21, s22 must be integers in [0, m2 - 1] and not all 0.
+ */
+ private double s10, s11, s12,
+ s20, s21, s22;
+
+ /**
+ * The seed generator for default constructors.
+ */
+ private static final AtomicLong defaultGen = new AtomicLong(RngSupport.initialSeed());
+
+ /*
+ 32-bits Random number generator U(0,1): MRG32k3a
+ Author: Pierre L'Ecuyer,
+ Source: Good Parameter Sets for Combined Multiple Recursive Random
+ Number Generators,
+ Shorter version in Operations Research,
+ 47, 1 (1999), 159--164.
+ ---------------------------------------------------------
+ */
+
+ private void nextState() {
+ /* Component 1 */
+ double p1 = a12 * s11 - a13n * s10;
+ double k1 = p1 / m1; p1 -= k1 * m1; if (p1 < 0.0) p1 += m1;
+ s10 = s11; s11 = s12; s12 = p1;
+ /* Component 2 */
+ double p2 = a21 * s22 - a23n * s20;
+ double k2 = p2 / m2; p2 -= k2 * m2; if (p2 < 0.0) p2 += m2;
+ s20 = s21; s21 = s22; s22 = p2;
+ }
+
+
+ /**
+ * The form of nextInt used by IntStream Spliterators.
+ * Exactly the same as long version, except for types.
+ *
+ * @param origin the least value, unless greater than bound
+ * @param bound the upper bound (exclusive), must not equal origin
+ * @return a pseudorandom value
+ */
+ private int internalNextInt(int origin, int bound) {
+ if (origin < bound) {
+ final int n = bound - origin;
+ final int m = n - 1;
+ if (n > 0) {
+ int r;
+ for (int u = (int)nextDouble() >>> 1;
+ u + m + ((m1_deficit + 1) >>> 1) - (r = u % n) < 0;
+ u = (int)nextDouble() >>> 1)
+ ;
+ return (r + origin);
+ } else {
+ return RngSupport.boundedNextInt(this, origin, bound);
+ }
+ } else {
+ return nextInt();
+ }
+ }
+
+ private int internalNextInt(int bound) {
+ // Specialize internalNextInt for origin == 0, bound > 0
+ final int n = bound;
+ final int m = n - 1;
+ int r;
+ for (int u = (int)nextDouble() >>> 1;
+ u + m + ((m1_deficit + 1) >>> 1) - (r = u % n) < 0;
+ u = (int)nextDouble() >>> 1)
+ ;
+ return r;
+ }
+
+ /**
+ * All arguments must be known to be nonnegative integral values
+ * less than the appropriate modulus.
+ */
+ private MRG32k3a(double s10, double s11, double s12,
+ double s20, double s21, double s22) {
+ this.s10 = s10; this.s11 = s11; this.s12 = s12;
+ this.s20 = s20; this.s21 = s21; this.s22 = s22;
+ if ((s10 == 0.0) && (s11 == 0.0) && (s12 == 0.0)) {
+ this.s10 = this.s11 = this.s12 = 12345.0;
+ }
+ if ((s20 == 0.0) && (s21 == 0.0) && (s22 == 0.0)) {
+ this.s20 = this.s21 = this.s21 = 12345.0;
+ }
+ }
+
+ /* ---------------- public methods ---------------- */
+
+ /**
+ * Creates a new MRG32k3a instance using six specified {@code int}
+ * initial seed values. MRG32k3a instances created with the same
+ * seeds in the same program generate identical sequences of values.
+ * If all six seed values are zero, the generator is seeded to a
+ * widely used initialization of MRG32k3a: all six state variables
+ * are set to 12345.
+ *
+ * @param s10 the first seed value for the first subgenerator
+ * @param s11 the second seed value for the first subgenerator
+ * @param s12 the third seed value for the first subgenerator
+ * @param s20 the first seed value for the second subgenerator
+ * @param s21 the second seed value for the second subgenerator
+ * @param s22 the third seed value for the second subgenerator
+ */
+ public MRG32k3a(int s10, int s11, int s12,
+ int s20, int s21, int s22) {
+ this(((double)(((long)s10) & 0x00000000ffffffffL)) % m1,
+ ((double)(((long)s11) & 0x00000000ffffffffL)) % m1,
+ ((double)(((long)s12) & 0x00000000ffffffffL)) % m1,
+ ((double)(((long)s20) & 0x00000000ffffffffL)) % m2,
+ ((double)(((long)s21) & 0x00000000ffffffffL)) % m2,
+ ((double)(((long)s22) & 0x00000000ffffffffL)) % m2);
+ }
+
+ /**
+ * Creates a new MRG32k3a instance using the specified
+ * initial seed. MRG32k3a instances created with the same
+ * seed in the same program generate identical sequences of values.
+ * An argument of 0 seeds the generator to a widely used initialization
+ * of MRG32k3a: all six state variables are set to 12345.
+ *
+ * @param seed the initial seed
+ */
+ public MRG32k3a(long seed) {
+ this((double)((seed & 0x7FF) + 12345),
+ (double)(((seed >>> 11) & 0x7FF) + 12345),
+ (double)(((seed >>> 22) & 0x7FF) + 12345),
+ (double)(((seed >>> 33) & 0x7FF) + 12345),
+ (double)(((seed >>> 44) & 0x7FF) + 12345),
+ (double)((seed >>> 55) + 12345));
+ }
+
+ /**
+ * Creates a new MRG32k3a instance that is likely to
+ * generate sequences of values that are statistically independent
+ * of those of any other instances in the current program; and
+ * may, and typically does, vary across program invocations.
+ */
+ public MRG32k3a() {
+ this(defaultGen.getAndAdd(RngSupport.GOLDEN_RATIO_64));
+ }
+
+ /**
+ * Creates a new instance of {@code Xoshiro256StarStar} using the specified array of
+ * initial seed bytes. Instances of {@code Xoshiro256StarStar} created with the same
+ * seed array in the same program execution generate identical sequences of values.
+ *
+ * @param seed the initial seed
+ */
+ public MRG32k3a(byte[] seed) {
+ // Convert the seed to 6 int values.
+ int[] data = RngSupport.convertSeedBytesToInts(seed, 6, 0);
+ int s10 = data[0], s11 = data[1], s12 = data[2];
+ int s20 = data[3], s21 = data[4], s22 = data[5];
+ this.s10 = ((double)(((long)s10) & 0x00000000ffffffffL)) % m1;
+ this.s11 = ((double)(((long)s11) & 0x00000000ffffffffL)) % m1;
+ this.s12 = ((double)(((long)s12) & 0x00000000ffffffffL)) % m1;
+ this.s20 = ((double)(((long)s20) & 0x00000000ffffffffL)) % m2;
+ this.s21 = ((double)(((long)s21) & 0x00000000ffffffffL)) % m2;
+ this.s22 = ((double)(((long)s22) & 0x00000000ffffffffL)) % m2;
+ if ((s10 == 0.0) && (s11 == 0.0) && (s12 == 0.0)) {
+ this.s10 = this.s11 = this.s12 = 12345.0;
+ }
+ if ((s20 == 0.0) && (s21 == 0.0) && (s22 == 0.0)) {
+ this.s20 = this.s21 = this.s21 = 12345.0;
+ }
+ }
+
+ public MRG32k3a copy() { return new MRG32k3a(s10, s11, s12, s20, s21, s22); }
+
+ /**
+ * Returns a pseudorandom {@code double} value between zero
+ * (exclusive) and one (exclusive).
+ *
+ * @return a pseudorandom {@code double} value between zero
+ * (exclusive) and one (exclusive)
+ */
+ public double nextOpenDouble() {
+ nextState();
+ double p1 = s12, p2 = s22;
+ if (p1 <= p2)
+ return ((p1 - p2 + m1) * norm1);
+ else
+ return ((p1 - p2) * norm1);
+ }
+
+ /**
+ * Returns a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive).
+ *
+ * @return a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive)
+ */
+ public double nextDouble() {
+ nextState();
+ double p1 = s12, p2 = s22;
+ final double p = p1 * norm1 - p2 * norm2;
+ if (p < 0.0) return (p + 1.0);
+ else return p;
+ }
+
+
+ /**
+ * Returns a pseudorandom {@code float} value between zero
+ * (inclusive) and one (exclusive).
+ *
+ * @return a pseudorandom {@code float} value between zero
+ * (inclusive) and one (exclusive)
+ */
+ public float nextFloat() {
+ return (float)nextDouble();
+ }
+
+ /**
+ * Returns a pseudorandom {@code int} value.
+ *
+ * @return a pseudorandom {@code int} value
+ */
+ public int nextInt() {
+ return (internalNextInt(0x10000) << 16) | internalNextInt(0x10000);
+ }
+
+ /**
+ * Returns a pseudorandom {@code long} value.
+ *
+ * @return a pseudorandom {@code long} value
+ */
+
+ public long nextLong() {
+ return (((long)internalNextInt(0x200000) << 43) |
+ ((long)internalNextInt(0x200000) << 22) |
+ ((long)internalNextInt(0x400000)));
+ }
+
+ // Period is (m1**3 - 1)(m2**3 - 1)/2, or approximately 2**191.
+ static BigInteger calculateThePeriod() {
+ BigInteger bigm1 = BigInteger.valueOf((long)m1);
+ BigInteger bigm2 = BigInteger.valueOf((long)m2);
+ BigInteger t1 = bigm1.multiply(bigm1).multiply(bigm1).subtract(BigInteger.ONE);
+ BigInteger t2 = bigm2.multiply(bigm2).multiply(bigm2).subtract(BigInteger.ONE);
+ return t1.shiftRight(1).multiply(t2);
+ }
+ static final BigInteger thePeriod = calculateThePeriod();
+ public BigInteger period() { return thePeriod; }
+
+ // Jump and leap distances recommended in Section 1.3 of this paper:
+ // Pierre L'Ecuyer, Richard Simard, E. Jack Chen, and W. David Kelton.
+ // An Object-Oriented Random-Number Package with Many Long Streams and Substreams.
+ // Operations Research 50, 6 (Nov--Dec 2002), 1073--1075.
+
+ public double defaultJumpDistance() { return 0x1.0p76; } // 2**76
+ public double defaultLeapDistance() { return 0x1.0p127; } // 2**127
+
+ public void jump(double distance) {
+ if (distance < 0.0 || Double.isInfinite(distance) || distance != Math.floor(distance))
+ throw new IllegalArgumentException("jump distance must be a nonnegative finite integer");
+ // We will compute a jump transformation (s => M s) for each LCG.
+ // We initialize each transformation to the identity transformation.
+ // Each will be turned into the d'th power of the corresponding base transformation.
+ long m1_00 = 1, m1_01 = 0, m1_02 = 0,
+ m1_10 = 0, m1_11 = 1, m1_12 = 0,
+ m1_20 = 0, m1_21 = 0, m1_22 = 1;
+ long m2_00 = 1, m2_01 = 0, m2_02 = 0,
+ m2_10 = 0, m2_11 = 1, m2_12 = 0,
+ m2_20 = 0, m2_21 = 0, m2_22 = 1;
+ // These are the base transformations, which will be repeatedly squared,
+ // and composed with the computed transformations for each 1-bit in distance.
+ long t1_00 = 0, t1_01 = 1, t1_02 = 0,
+ t1_10 = 0, t1_11 = 0, t1_12 = 1,
+ t1_20 = -(long)a13n, t1_21 = (long)a12, t1_22 = 0;
+ long t2_00 = 0, t2_01 = 1, t2_02 = 0,
+ t2_10 = 0, t2_11 = 0, t2_12 = 1,
+ t2_20 = -(long)a23n, t2_21 = (long)a21, t2_22 = 0;
+ while (distance > 0.0) {
+ final double dhalf = 0.5 * distance;
+ if (Math.floor(dhalf) != dhalf) {
+ // distance is odd: accumulate current squaring
+ final long n1_00 = m1_00 * t1_00 + m1_01 * t1_10 + m1_02 * t1_20;
+ final long n1_01 = m1_00 * t1_01 + m1_01 * t1_11 + m1_02 * t1_21;
+ final long n1_02 = m1_00 * t1_02 + m1_01 * t1_12 + m1_02 * t1_22;
+ final long n1_10 = m1_10 * t1_00 + m1_11 * t1_10 + m1_12 * t1_20;
+ final long n1_11 = m1_10 * t1_01 + m1_11 * t1_11 + m1_12 * t1_21;
+ final long n1_12 = m1_10 * t1_02 + m1_11 * t1_12 + m1_12 * t1_22;
+ final long n1_20 = m1_20 * t1_00 + m1_21 * t1_10 + m1_22 * t1_20;
+ final long n1_21 = m1_20 * t1_01 + m1_21 * t1_11 + m1_22 * t1_21;
+ final long n1_22 = m1_20 * t1_02 + m1_21 * t1_12 + m1_22 * t1_22;
+ m1_00 = Math.floorMod(n1_00, (long)m1);
+ m1_01 = Math.floorMod(n1_01, (long)m1);
+ m1_02 = Math.floorMod(n1_02, (long)m1);
+ m1_10 = Math.floorMod(n1_10, (long)m1);
+ m1_11 = Math.floorMod(n1_11, (long)m1);
+ m1_12 = Math.floorMod(n1_12, (long)m1);
+ m1_20 = Math.floorMod(n1_20, (long)m1);
+ m1_21 = Math.floorMod(n1_21, (long)m1);
+ m1_22 = Math.floorMod(n1_22, (long)m1);
+ final long n2_00 = m2_00 * t2_00 + m2_01 * t2_10 + m2_02 * t2_20;
+ final long n2_01 = m2_00 * t2_01 + m2_01 * t2_11 + m2_02 * t2_21;
+ final long n2_02 = m2_00 * t2_02 + m2_01 * t2_12 + m2_02 * t2_22;
+ final long n2_10 = m2_10 * t2_00 + m2_11 * t2_10 + m2_12 * t2_20;
+ final long n2_11 = m2_10 * t2_01 + m2_11 * t2_11 + m2_12 * t2_21;
+ final long n2_12 = m2_10 * t2_02 + m2_11 * t2_12 + m2_12 * t2_22;
+ final long n2_20 = m2_20 * t2_00 + m2_21 * t2_10 + m2_22 * t2_20;
+ final long n2_21 = m2_20 * t2_01 + m2_21 * t2_11 + m2_22 * t2_21;
+ final long n2_22 = m2_20 * t2_02 + m2_21 * t2_12 + m2_22 * t2_22;
+ m2_00 = Math.floorMod(n2_00, (long)m2);
+ m2_01 = Math.floorMod(n2_01, (long)m2);
+ m2_02 = Math.floorMod(n2_02, (long)m2);
+ m2_10 = Math.floorMod(n2_10, (long)m2);
+ m2_11 = Math.floorMod(n2_11, (long)m2);
+ m2_12 = Math.floorMod(n2_12, (long)m2);
+ m2_20 = Math.floorMod(n2_20, (long)m2);
+ m2_21 = Math.floorMod(n2_21, (long)m2);
+ m2_22 = Math.floorMod(n2_22, (long)m2);
+ }
+ // Square the base transformations.
+ {
+ final long z1_00 = m1_00 * m1_00 + m1_01 * m1_10 + m1_02 * m1_20;
+ final long z1_01 = m1_00 * m1_01 + m1_01 * m1_11 + m1_02 * m1_21;
+ final long z1_02 = m1_00 * m1_02 + m1_01 * m1_12 + m1_02 * m1_22;
+ final long z1_10 = m1_10 * m1_00 + m1_11 * m1_10 + m1_12 * m1_20;
+ final long z1_11 = m1_10 * m1_01 + m1_11 * m1_11 + m1_12 * m1_21;
+ final long z1_12 = m1_10 * m1_02 + m1_11 * m1_12 + m1_12 * m1_22;
+ final long z1_20 = m1_20 * m1_00 + m1_21 * m1_10 + m1_22 * m1_20;
+ final long z1_21 = m1_20 * m1_01 + m1_21 * m1_11 + m1_22 * m1_21;
+ final long z1_22 = m1_20 * m1_02 + m1_21 * m1_12 + m1_22 * m1_22;
+ m1_00 = Math.floorMod(z1_00, (long)m1);
+ m1_01 = Math.floorMod(z1_01, (long)m1);
+ m1_02 = Math.floorMod(z1_02, (long)m1);
+ m1_10 = Math.floorMod(z1_10, (long)m1);
+ m1_11 = Math.floorMod(z1_11, (long)m1);
+ m1_12 = Math.floorMod(z1_12, (long)m1);
+ m1_20 = Math.floorMod(z1_20, (long)m1);
+ m1_21 = Math.floorMod(z1_21, (long)m1);
+ m1_22 = Math.floorMod(z1_22, (long)m1);
+ final long z2_00 = m2_00 * m2_00 + m2_01 * m2_10 + m2_02 * m2_20;
+ final long z2_01 = m2_00 * m2_01 + m2_01 * m2_11 + m2_02 * m2_21;
+ final long z2_02 = m2_00 * m2_02 + m2_01 * m2_12 + m2_02 * m2_22;
+ final long z2_10 = m2_10 * m2_00 + m2_11 * m2_10 + m2_12 * m2_20;
+ final long z2_11 = m2_10 * m2_01 + m2_11 * m2_11 + m2_12 * m2_21;
+ final long z2_12 = m2_10 * m2_02 + m2_11 * m2_12 + m2_12 * m2_22;
+ final long z2_20 = m2_20 * m2_00 + m2_21 * m2_10 + m2_22 * m2_20;
+ final long z2_21 = m2_20 * m2_01 + m2_21 * m2_11 + m2_22 * m2_21;
+ final long z2_22 = m2_20 * m2_02 + m2_21 * m2_12 + m2_22 * m2_22;
+ m2_00 = Math.floorMod(z2_00, (long)m2);
+ m2_01 = Math.floorMod(z2_01, (long)m2);
+ m2_02 = Math.floorMod(z2_02, (long)m2);
+ m2_10 = Math.floorMod(z2_10, (long)m2);
+ m2_11 = Math.floorMod(z2_11, (long)m2);
+ m2_12 = Math.floorMod(z2_12, (long)m2);
+ m2_20 = Math.floorMod(z2_20, (long)m2);
+ m2_21 = Math.floorMod(z2_21, (long)m2);
+ m2_22 = Math.floorMod(z2_22, (long)m2);
+ }
+ // Divide distance by 2.
+ distance = dhalf;
+ }
+ final long w10 = m1_00 * (long)s10 + m1_01 * (long)s11 + m1_02 * (long)s12;
+ final long w11 = m1_10 * (long)s10 + m1_11 * (long)s11 + m1_12 * (long)s12;
+ final long w12 = m1_20 * (long)s10 + m1_21 * (long)s11 + m1_22 * (long)s12;
+ s10 = Math.floorMod(w10, (long)m1);
+ s11 = Math.floorMod(w11, (long)m1);
+ s12 = Math.floorMod(w12, (long)m1);
+ final long w20 = m2_00 * (long)s20 + m2_01 * (long)s21 + m2_02 * (long)s22;
+ final long w21 = m2_10 * (long)s20 + m2_11 * (long)s21 + m2_12 * (long)s22;
+ final long w22 = m2_20 * (long)s20 + m2_21 * (long)s21 + m2_22 * (long)s22;
+ s20 = Math.floorMod(w20, (long)m2);
+ s21 = Math.floorMod(w21, (long)m2);
+ s22 = Math.floorMod(w22, (long)m2);
+ }
+
+ /**
+ * Alter the state of this pseudorandom number generator so as to
+ * jump forward a distance equal to 2<sup>{@code logDistance}</sup>
+ * within its state cycle.
+ *
+ * @param logDistance the base-2 logarithm of the distance to jump
+ * forward within the state cycle. Must be non-negative and
+ * not greater than 192.
+ * @throws IllegalArgumentException if {@code logDistance} is
+ * less than zero or 2<sup>{@code logDistance}</sup> is
+ * greater than the period of this generator
+ */
+ public void jumpPowerOfTwo(int logDistance) {
+ if (logDistance < 0 || logDistance > 192)
+ throw new IllegalArgumentException(BadLogDistance);
+ jump(Math.scalb(1.0, logDistance));
+ }
+
+}