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+package gregtech.api.objects;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+/*
+ * TODO: Check the validity of the algorithm.
+ * There is a claim that this particular implementation is not faithful to the articles it links, skewing the
+ * distribution.
+ */
+/**
+ * XSTR - Xorshift ThermiteRandom Modified by Bogdan-G 03.06.2016 version 0.0.4
+ * <p>
+ * A subclass of java.util.random that implements the Xorshift random number generator
+ * <p>
+ * - it is 30% faster than the generator from Java's library - it produces random sequences of higher quality than
+ * java.util.Random - this class also provides a clone() function
+ * <p>
+ * Usage: XSRandom rand = new XSRandom(); //Instantiation x = rand.nextInt(); //pull a random number
+ * <p>
+ * To use the class in legacy code, you may also instantiate an XSRandom object and assign it to a java.util.Random
+ * object: java.util.Random rand = new XSRandom();
+ * <p>
+ * for an explanation of the algorithm, see http://demesos.blogspot.com/2011/09/pseudo-random-number-generators.html
+ *
+ * @author Wilfried Elmenreich University of Klagenfurt/Lakeside Labs http://www.elmenreich.tk
+ * <p>
+ * This code is released under the GNU Lesser General Public License Version 3
+ * http://www.gnu.org/licenses/lgpl-3.0.txt
+ */
+public class XSTR extends Random {
+
+ private static final long serialVersionUID = 6208727693524452904L;
+ private long seed;
+ private long last;
+ private static final long GAMMA = 0x9e3779b97f4a7c15L;
+ private static final int PROBE_INCREMENT = 0x9e3779b9;
+ private static final long SEEDER_INCREMENT = 0xbb67ae8584caa73bL;
+ private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
+ private static final float FLOAT_UNIT = 0x1.0p-24f; // 1.0f / (1 << 24)
+ private static final AtomicLong seedUniquifier = new AtomicLong(8682522807148012L);
+ public static final XSTR XSTR_INSTANCE = new XSTR() {
+
+ @Override
+ public synchronized void setSeed(long seed) {
+ if (!Thread.currentThread()
+ .getStackTrace()[2].getClassName()
+ .equals(Random.class.getName()))
+ throw new NoSuchMethodError("This is meant to be shared!, leave seed state alone!");
+ }
+ };
+
+ /*
+ * MODIFIED BY: Robotia Modification: Implemented Random class seed generator
+ */
+ /**
+ * Creates a new pseudo random number generator. The seed is initialized to the current time, as if by
+ * <code>setSeed(System.currentTimeMillis());</code>.
+ */
+ public XSTR() {
+ this(seedUniquifier() ^ System.nanoTime());
+ }
+
+ private static long seedUniquifier() {
+ // L'Ecuyer, "Tables of Linear Congruential Generators of
+ // Different Sizes and Good Lattice Structure", 1999
+ for (;;) {
+ long current = seedUniquifier.get();
+ long next = current * 181783497276652981L;
+ if (seedUniquifier.compareAndSet(current, next)) {
+ return next;
+ }
+ }
+ }
+
+ /**
+ * Creates a new pseudo random number generator, starting with the specified seed, using
+ * <code>setSeed(seed);</code>.
+ *
+ * @param seed the initial seed
+ */
+ public XSTR(long seed) {
+ this.seed = seed;
+ }
+
+ @Override
+ public boolean nextBoolean() {
+ return next(1) != 0;
+ }
+
+ @Override
+ public double nextDouble() {
+ return (((long) (next(26)) << 27) + next(27)) * DOUBLE_UNIT;
+ }
+
+ /**
+ * Returns the current state of the seed, can be used to clone the object
+ *
+ * @return the current seed
+ */
+ public synchronized long getSeed() {
+ return seed;
+ }
+
+ /**
+ * Sets the seed for this pseudo random number generator. As described above, two instances of the same random
+ * class, starting with the same seed, produce the same results, if the same methods are called.
+ *
+ * @param seed the new seed
+ */
+ @Override
+ public synchronized void setSeed(long seed) {
+ this.seed = seed;
+ }
+
+ /**
+ * @return Returns an XSRandom object with the same state as the original
+ */
+ @Override
+ public XSTR clone() {
+ return new XSTR(getSeed());
+ }
+
+ /**
+ * Implementation of George Marsaglia's Xorshift random generator that is 30% faster and better quality than the
+ * built-in java.util.random.
+ *
+ * @param nbits number of bits to shift the result for
+ * @return a random integer
+ * @see <a href="https://www.javamex.com/tutorials/random_numbers/xorshift.shtml">the Xorshift article</a>
+ */
+ @Override
+ public int next(int nbits) {
+ long x = seed;
+ x ^= (x << 21);
+ x ^= (x >>> 35);
+ x ^= (x << 4);
+ seed = x;
+ x &= ((1L << nbits) - 1);
+ return (int) x;
+ }
+
+ boolean haveNextNextGaussian = false;
+ double nextNextGaussian = 0;
+
+ @Override
+ public synchronized double nextGaussian() {
+ // See Knuth, ACP, Section 3.4.1 Algorithm C.
+ if (haveNextNextGaussian) {
+ haveNextNextGaussian = false;
+ return nextNextGaussian;
+ } else {
+ double v1, v2, s;
+ do {
+ v1 = 2 * nextDouble() - 1; // between -1 and 1
+ v2 = 2 * nextDouble() - 1; // between -1 and 1
+ s = v1 * v1 + v2 * v2;
+ } while (s >= 1 || s == 0);
+ double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s) / s);
+ nextNextGaussian = v2 * multiplier;
+ haveNextNextGaussian = true;
+ return v1 * multiplier;
+ }
+ }
+
+ /**
+ * Returns a pseudorandom, uniformly distributed {@code int} value between 0 (inclusive) and the specified value
+ * (exclusive), drawn from this random number generator's sequence. The general contract of {@code nextInt} is that
+ * one {@code int} value in the specified range is pseudorandomly generated and returned. All {@code bound} possible
+ * {@code int} values are produced with (approximately) equal probability. The method {@code nextInt(int bound)} is
+ * implemented by class {@code Random} as if by:
+ *
+ * <pre>
+ * {@code
+ * public int nextInt(int bound) {
+ * if (bound <= 0)
+ * throw new IllegalArgumentException("bound must be positive");
+ *
+ * if ((bound & -bound) == bound) // i.e., bound is a power of 2
+ * return (int)((bound * (long)next(31)) >> 31);
+ *
+ * int bits, val;
+ * do {
+ * bits = next(31);
+ * val = bits % bound;
+ * } while (bits - val + (bound-1) < 0);
+ * return val;
+ * }}
+ * </pre>
+ *
+ * <p>
+ * The next method is only approximately an unbiased source of independently chosen bits. If it were a perfect
+ * source of randomly chosen bits, then the algorithm shown would choose {@code int} values from the stated range
+ * with perfect uniformity.
+ * <p>
+ * The algorithm is slightly tricky. It rejects values that would result in an uneven distribution (due to the fact
+ * that 2^31 is not divisible by n). The probability of a value being rejected depends on n. The worst case is
+ * n=2^30+1, for which the probability of a reject is 1/2, and the expected number of iterations before the loop
+ * terminates is 2.
+ * <p>
+ * The algorithm treats the case where n is a power of two specially: it returns the correct number of high-order
+ * bits from the underlying pseudo-random number generator. In the absence of special treatment, the correct number
+ * of <i>low-order</i> bits would be returned. Linear congruential pseudo-random number generators such as the one
+ * implemented by this class are known to have short periods in the sequence of values of their low-order bits.
+ * Thus, this special case greatly increases the length of the sequence of values returned by successive calls to
+ * this method if n is a small power of two.
+ *
+ * @param bound the upper bound (exclusive). Must be positive.
+ * @return the next pseudorandom, uniformly distributed {@code int} value between zero (inclusive) and {@code bound}
+ * (exclusive) from this random number generator's sequence
+ * @throws IllegalArgumentException if bound is not positive
+ * @since 1.2
+ */
+ @Override
+ public int nextInt(int bound) {
+ last = seed ^ (seed << 21);
+ last ^= (last >>> 35);
+ last ^= (last << 4);
+ seed = last;
+ int out = (int) last % bound;
+ return (out < 0) ? -out : out;
+ }
+
+ @Override
+ public int nextInt() {
+ return next(32);
+ }
+
+ @Override
+ public float nextFloat() {
+ return next(24) * FLOAT_UNIT;
+ }
+
+ @Override
+ public long nextLong() {
+ // it's okay that the bottom word remains signed.
+ return ((long) (next(32)) << 32) + next(32);
+ }
+
+ @Override
+ public void nextBytes(byte[] bytes_arr) {
+ for (int iba = 0, lenba = bytes_arr.length; iba < lenba;)
+ for (int rndba = nextInt(), nba = Math.min(lenba - iba, Integer.SIZE / Byte.SIZE); nba--
+ > 0; rndba >>= Byte.SIZE) bytes_arr[iba++] = (byte) rndba;
+ }
+}