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Comparing jsr166/src/main/java/util/SplittableRandom.java (file contents):
Revision 1.13 by dl, Thu Jul 25 13:19:09 2013 UTC vs.
Revision 1.21 by dl, Thu Sep 19 23:19:43 2013 UTC

#	Line 26 | Line 26
26		package java.util;
27
28		import java.security.SecureRandom;
29	+	import java.net.NetworkInterface;
30	+	import java.util.Enumeration;
31		import java.util.concurrent.atomic.AtomicLong;
30	–	import java.util.Spliterator;
32		import java.util.function.IntConsumer;
33		import java.util.function.LongConsumer;
34		import java.util.function.DoubleConsumer;
#	Line 39 | Line 40 | import java.util.stream.DoubleStream;
40		/**
41		* A generator of uniform pseudorandom values applicable for use in
42		* (among other contexts) isolated parallel computations that may
43	<	* generate subtasks. Class SplittableRandom supports methods for
43	>	* generate subtasks. Class {@code SplittableRandom} supports methods for
44		* producing pseudorandom numbers of type {@code int}, {@code long},
45		* and {@code double} with similar usages as for class
46		* {@link java.util.Random} but differs in the following ways:
#	Line 77 | Line 78 | import java.util.stream.DoubleStream;
78		*
79		* </ul>
80		*
81	+	* <p>Instances of {@code SplittableRandom} are not cryptographically
82	+	* secure.  Consider instead using {@link java.security.SecureRandom}
83	+	* in security-sensitive applications. Additionally,
84	+	* default-constructed instances do not use a cryptographically random
85	+	* seed unless the {@linkplain System#getProperty system property}
86	+	* {@code java.util.secureRandomSeed} is set to {@code true}.
87	+	*
88		* @author  Guy Steele
89		* @author  Doug Lea
90		* @since   1.8
#	Line 84 | Line 92 | import java.util.stream.DoubleStream;
92		public class SplittableRandom {
93
94		/*
87	–	* File organization: First the non-public methods that constitute
88	–	* the main algorithm, then the main public methods, followed by
89	–	* some custom spliterator classes needed for stream methods.
90	–	*
91	–	* Credits: Primary algorithm and code by Guy Steele.  Stream
92	–	* support methods by Doug Lea.  Documentation jointly produced
93	–	* with additional help from Brian Goetz.
94	–	*/
95	–
96	–	/*
95		* Implementation Overview.
96		*
97		* This algorithm was inspired by the "DotMix" algorithm by
98		* Leiserson, Schardl, and Sukha "Deterministic Parallel
99		* Random-Number Generation for Dynamic-Multithreading Platforms",
100	<	* PPoPP 2012, but improves and extends it in several ways.
100	>	* PPoPP 2012, as well as those in "Parallel random numbers: as
101	>	* easy as 1, 2, 3" by Salmon, Morae, Dror, and Shaw, SC 2011.  It
102	>	* differs mainly in simplifying and cheapening operations.
103	>	*
104	>	* The primary update step (method nextSeed()) is to add a
105	>	* constant ("gamma") to the current (64 bit) seed, forming a
106	>	* simple sequence.  The seed and the gamma values for any two
107	>	* SplittableRandom instances are highly likely to be different.
108	>	*
109	>	* Methods nextLong, nextInt, and derivatives do not return the
110	>	* sequence (seed) values, but instead a hash-like bit-mix of
111	>	* their bits, producing more independently distributed sequences.
112	>	* For nextLong, the mix64 function is based on David Stafford's
113	>	* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html)
114	>	* "Mix13" variant of the "64-bit finalizer" function in Austin
115	>	* Appleby's MurmurHash3 algorithm See
116	>	* http://code.google.com/p/smhasher/wiki/MurmurHash3 . The mix32
117	>	* function is based on Stafford's Mix04 mix function, but returns
118	>	* the upper 32 bits cast as int.
119	>	*
120	>	* The split operation uses the current generator to form the seed
121	>	* and gamma for another SplittableRandom.  To conservatively
122	>	* avoid potential correlations between seed and value generation,
123	>	* gamma selection (method mixGamma) uses different
124	>	* (Murmurhash3's) mix constants.  To avoid potential weaknesses
125	>	* in bit-mixing transformations, we restrict gammas to odd values
126	>	* with at least 24 0-1 or 1-0 bit transitions.  Rather than
127	>	* rejecting candidates with too few or too many bits set, method
128	>	* mixGamma flips some bits (which has the effect of mapping at
129	>	* most 4 to any given gamma value).  This reduces the effective
130	>	* set of 64bit odd gamma values by about 2%, and serves as an
131	>	* automated screening for sequence constant selection that is
132	>	* left as an empirical decision in some other hashing and crypto
133	>	* algorithms.
134	>	*
135	>	* The resulting generator thus transforms a sequence in which
136	>	* (typically) many bits change on each step, with an inexpensive
137	>	* mixer with good (but less than cryptographically secure)
138	>	* avalanching.
139	>	*
140	>	* The default (no-argument) constructor, in essence, invokes
141	>	* split() for a common "defaultGen" SplittableRandom.  Unlike
142	>	* other cases, this split must be performed in a thread-safe
143	>	* manner, so we use an AtomicLong to represent the seed rather
144	>	* than use an explicit SplittableRandom. To bootstrap the
145	>	* defaultGen, we start off using a seed based on current time and
146	>	* network interface address unless the java.util.secureRandomSeed
147	>	* property is set. This serves as a slimmed-down (and insecure)
148	>	* variant of SecureRandom that also avoids stalls that may occur
149	>	* when using /dev/random.
150	>	*
151	>	* It is a relatively simple matter to apply the basic design here
152	>	* to use 128 bit seeds. However, emulating 128bit arithmetic and
153	>	* carrying around twice the state add more overhead than appears
154	>	* warranted for current usages.
155		*
156	<	* The primary update step (see method nextSeed()) is simply to
157	<	* add a constant ("gamma") to the current seed, modulo a prime
158	<	* ("George"). However, the nextLong and nextInt methods do not
107	<	* return this value, but instead the results of bit-mixing
108	<	* transformations that produce more uniformly distributed
109	<	* sequences.
110	<	*
111	<	* "George" is the otherwise nameless (because it cannot be
112	<	* represented) prime number 2^64+13. Using a prime number larger
113	<	* than can fit in a long ensures that all possible long values
114	<	* can occur, plus 13 others that just get skipped over when they
115	<	* are encountered; see method addGammaModGeorge. For this to
116	<	* work, initial gamma values must be at least 13.
117	<	*
118	<	* The mix64 bit-mixing function called by nextLong and other
119	<	* methods computes the same value as the "64-bit finalizer"
120	<	* function in Austin Appleby's MurmurHash3 algorithm.  See
121	<	* http://code.google.com/p/smhasher/wiki/MurmurHash3 , which
122	<	* comments: "The constants for the finalizers were generated by a
123	<	* simple simulated-annealing algorithm, and both avalanche all
124	<	* bits of 'h' to within 0.25% bias."
125	<	*
126	<	* The value of gamma differs for each instance across a series of
127	<	* splits, and is generated using an independent variant of the
128	<	* same algorithm, but operating across calls to split(), not
129	<	* calls to nextSeed(): Each instance carries the state of this
130	<	* generator as nextSplit. Gammas are treated as 57bit values,
131	<	* advancing by adding GAMMA_GAMMA mod GAMMA_PRIME, and bit-mixed
132	<	* with a 57-bit version of mix, using the "Mix01" multiplicative
133	<	* constants for MurmurHash3 described by David Stafford
134	<	* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html).
135	<	* The value of GAMMA_GAMMA is arbitrary (except must be at least
136	<	* 13 and less than GAMMA_PRIME), but because it serves as the
137	<	* base of split sequences, should be subject to validation of
138	<	* consequent random number quality metrics.
139	<	*
140	<	* The mix32 function used for nextInt just consists of two of the
141	<	* five lines of mix64; avalanche testing shows that the 64-bit
142	<	* result has its top 32 bits avalanched well, though not the
143	<	* bottom 32 bits.  DieHarder tests show that it is adequate for
144	<	* generating one random int from the 64-bit result of nextSeed.
145	<	*
146	<	* Support for the default (no-argument) constructor relies on an
147	<	* AtomicLong (defaultSeedGenerator) to help perform the
148	<	* equivalent of a split of a statically constructed
149	<	* SplittableRandom. Unlike other cases, this split must be
150	<	* performed in a thread-safe manner. We use
151	<	* AtomicLong.compareAndSet as the (typically) most efficient
152	<	* mechanism. To bootstrap, we start off using a SecureRandom
153	<	* initial default seed, and update using a fixed
154	<	* DEFAULT_SEED_GAMMA. The default constructor uses GAMMA_GAMMA,
155	<	* not 0, for its splitSeed argument (addGammaModGeorge(0,
156	<	* GAMMA_GAMMA) == GAMMA_GAMMA) to reflect that each is split from
157	<	* this root generator, even though the root is not explicitly
158	<	* represented as a SplittableRandom.
159	<	*/
160	<
161	<	/**
162	<	* The prime modulus for gamma values.
163	<	*/
164	<	private static final long GAMMA_PRIME = (1L << 57) - 13L;
165	<
166	<	/**
167	<	* The value for producing new gamma values. Must be greater or
168	<	* equal to 13 and less than GAMMA_PRIME. Otherwise, the value is
169	<	* arbitrary subject to validation of the resulting statistical
170	<	* quality of splits.
171	<	*/
172	<	private static final long GAMMA_GAMMA = 0x00aae38294f712aabL;
173	<
174	<	/**
175	<	* The seed update value for default constructors.  Must be
176	<	* greater or equal to 13. Otherwise, the value is arbitrary
177	<	* subject to quality checks.
156	>	* File organization: First the non-public methods that constitute
157	>	* the main algorithm, then the main public methods, followed by
158	>	* some custom spliterator classes needed for stream methods.
159		*/
179	–	private static final long DEFAULT_SEED_GAMMA = 0x9e3779b97f4a7c15L;
160
161		/**
162	<	* The value 13 with 64bit sign bit set. Used in the signed
163	<	* comparison in addGammaModGeorge.
162	>	* The golden ratio scaled to 64bits, used as the initial gamma
163	>	* value for (unsplit) SplittableRandoms.
164		*/
165	<	private static final long BOTTOM13 = 0x800000000000000DL;
165	>	private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L;
166
167		/**
168		* The least non-zero value returned by nextDouble(). This value
169		* is scaled by a random value of 53 bits to produce a result.
170		*/
171	<	private static final double DOUBLE_UNIT = 1.0 / (1L << 53);
171	>	private static final double DOUBLE_ULP = 1.0 / (1L << 53);
172
173		/**
174	<	* The next seed for default constructors.
195	<	*/
196	<	private static final AtomicLong defaultSeedGenerator =
197	<	new AtomicLong(getInitialDefaultSeed());
198	<
199	<	/**
200	<	* The seed, updated only via method nextSeed.
174	>	* The seed. Updated only via method nextSeed.
175		*/
176		private long seed;
177
178		/**
179	<	* The constant value added to seed (mod George) on each update.
179	>	* The step value.
180		*/
181		private final long gamma;
182
183		/**
184	<	* The next seed to use for splits. Propagated using
211	<	* addGammaModGeorge across instances.
212	<	*/
213	<	private final long nextSplit;
214	<
215	<	/**
216	<	* Adds the given gamma value, g, to the given seed value s, mod
217	<	* George (2^64+13). We regard s and g as unsigned values
218	<	* (ranging from 0 to 2^64-1). We add g to s either once or twice
219	<	* (mod George) as necessary to produce an (unsigned) result less
220	<	* than 2^64.  We require that g must be at least 13. This
221	<	* guarantees that if (s+g) mod George >= 2^64 then (s+g+g) mod
222	<	* George < 2^64; thus we need only a conditional, not a loop,
223	<	* to be sure of getting a representable value.
224	<	*
225	<	* Because Java comparison operators are signed, we implement this
226	<	* by conceptually offsetting seed values downwards by 2^63, so
227	<	* 0..13 is represented as Long.MIN_VALUE..BOTTOM13.
228	<	*
229	<	* @param s a seed value, viewed as a signed long
230	<	* @param g a gamma value, 13 <= g (as unsigned)
184	>	* Internal constructor used by all others except default constructor.
185		*/
186	<	private static long addGammaModGeorge(long s, long g) {
187	<	long p = s + g;
188	<	return (p >= s) ? p : ((p >= BOTTOM13) ? p  : p + g) - 13L;
186	>	private SplittableRandom(long seed, long gamma) {
187	>	this.seed = seed;
188	>	this.gamma = gamma;
189		}
190
191		/**
192	<	* Returns a bit-mixed transformation of its argument.
239	<	* See above for explanation.
192	>	* Computes Stafford variant 13 of 64bit mix function.
193		*/
194		private static long mix64(long z) {
195	<	z ^= (z >>> 33);
196	<	z *= 0xff51afd7ed558ccdL;
197	<	z ^= (z >>> 33);
245	<	z *= 0xc4ceb9fe1a85ec53L;
246	<	z ^= (z >>> 33);
247	<	return z;
195	>	z *= 0xbf58476d1ce4e5b9L;
196	>	z = (z ^ (z >>> 32)) * 0x94d049bb133111ebL;
197	>	return z ^ (z >>> 32);
198		}
199
200	<	/**
201	<	* Returns a bit-mixed int transformation of its argument.
202	<	* See above for explanation.
203	<	*/
254	<	private static int mix32(long z) {
255	<	z ^= (z >>> 33);
256	<	z *= 0xc4ceb9fe1a85ec53L;
257	<	return (int)(z >>> 32);
200	>	private static long xmix64(long z) {
201	>	z *= 0xbf58476d1ce4e5b9L;
202	>	z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL;
203	>	return z ^ (z >>> 31);
204		}
205
206		/**
207	<	* Returns a 57-bit mixed transformation of its argument.  See
262	<	* above for explanation.
207	>	* Returns the 32 high bits of Stafford variant 4 mix64 function as int.
208		*/
209	<	private static long mix57(long z) {
210	<	z ^= (z >>> 33);
211	<	z *= 0x7fb5d329728ea185L;
267	<	z &= 0x01FFFFFFFFFFFFFFL;
268	<	z ^= (z >>> 33);
269	<	z *= 0x81dadef4bc2dd44dL;
270	<	z &= 0x01FFFFFFFFFFFFFFL;
271	<	z ^= (z >>> 33);
272	<	return z;
209	>	private static int mix32(long z) {
210	>	z *= 0x62a9d9ed799705f5L;
211	>	return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32);
212		}
213
214		/**
215	<	* Internal constructor used by all other constructors and by
277	<	* method split. Establishes the initial seed for this instance,
278	<	* and uses the given splitSeed to establish gamma, as well as the
279	<	* nextSplit to use by this instance. The loop to skip ineligible
280	<	* gammas very rarely iterates, and does so at most 13 times.
215	>	* Returns the gamma value to use for a new split instance.
216		*/
217	<	private SplittableRandom(long seed, long splitSeed) {
218	<	this.seed = seed;
219	<	long s = splitSeed, g;
220	<	do { // ensure gamma >= 13, considered as an unsigned integer
221	<	s += GAMMA_GAMMA;
222	<	if (s >= GAMMA_PRIME)
288	<	s -= GAMMA_PRIME;
289	<	g = mix57(s);
290	<	} while (g < 13L);
291	<	this.gamma = g;
292	<	this.nextSplit = s;
217	>	private static long mixGamma(long z) {
218	>	z *= 0xff51afd7ed558ccdL;                   // MurmurHash3 mix constants
219	>	z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
220	>	z = (z ^ (z >>> 33)) | 1L;                  // force to be odd
221	>	int n = Long.bitCount(z ^ (z >>> 1));       // ensure enough transitions
222	>	return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
223		}
224
225		/**
226	<	* Updates in-place and returns seed.
297	<	* See above for explanation.
226	>	* Adds gamma to seed.
227		*/
228		private long nextSeed() {
229	<	return seed = addGammaModGeorge(seed, gamma);
229	>	return seed += gamma;
230		}
231
232		/**
233	<	* Atomically updates and returns next seed for default constructor.
233	>	* The seed generator for default constructors.
234		*/
235	<	private static long nextDefaultSeed() {
307	<	long oldSeed, newSeed;
308	<	do {
309	<	oldSeed = defaultSeedGenerator.get();
310	<	newSeed = addGammaModGeorge(oldSeed, DEFAULT_SEED_GAMMA);
311	<	} while (!defaultSeedGenerator.compareAndSet(oldSeed, newSeed));
312	<	return mix64(newSeed);
313	<	}
235	>	private static final AtomicLong defaultGen = new AtomicLong(initialSeed());
236
237	<	/**
238	<	* Returns an initial default seed.
239	<	*/
240	<	private static long getInitialDefaultSeed() {
241	<	byte[] seedBytes = java.security.SecureRandom.getSeed(8);
242	<	long s = (long)(seedBytes[0]) & 0xffL;
243	<	for (int i = 1; i < 8; ++i)
244	<	s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
245	<	return s;
237	>	private static long initialSeed() {
238	>	String pp = java.security.AccessController.doPrivileged(
239	>	new sun.security.action.GetPropertyAction(
240	>	"java.util.secureRandomSeed"));
241	>	if (pp != null && pp.equalsIgnoreCase("true")) {
242	>	byte[] seedBytes = java.security.SecureRandom.getSeed(8);
243	>	long s = (long)(seedBytes[0]) & 0xffL;
244	>	for (int i = 1; i < 8; ++i)
245	>	s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
246	>	return s;
247	>	}
248	>	long h = 0L;
249	>	try {
250	>	Enumeration<NetworkInterface> ifcs =
251	>	NetworkInterface.getNetworkInterfaces();
252	>	boolean retry = false; // retry once if getHardwareAddress is null
253	>	while (ifcs.hasMoreElements()) {
254	>	NetworkInterface ifc = ifcs.nextElement();
255	>	if (!ifc.isVirtual()) { // skip fake addresses
256	>	byte[] bs = ifc.getHardwareAddress();
257	>	if (bs != null) {
258	>	int n = bs.length;
259	>	int m = Math.min(n >>> 1, 4);
260	>	for (int i = 0; i < m; ++i)
261	>	h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i];
262	>	if (m < 4)
263	>	h = (h << 8) ^ bs[n-1-m];
264	>	h = mix64(h);
265	>	break;
266	>	}
267	>	else if (!retry)
268	>	retry = true;
269	>	else
270	>	break;
271	>	}
272	>	}
273	>	} catch (Exception ignore) {
274	>	}
275	>	return (h ^ mix64(System.currentTimeMillis()) ^
276	>	mix64(System.nanoTime()));
277		}
278
279	+	// IllegalArgumentException messages
280	+	static final String BadBound = "bound must be positive";
281	+	static final String BadRange = "bound must be greater than origin";
282	+	static final String BadSize  = "size must be non-negative";
283	+
284		/*
285		* Internal versions of nextX methods used by streams, as well as
286		* the public nextX(origin, bound) methods.  These exist mainly to
#	Line 423 | Line 381 | public class SplittableRandom {
381		* @return a pseudorandom value
382		*/
383		final double internalNextDouble(double origin, double bound) {
384	<	double r = (nextLong() >>> 11) * DOUBLE_UNIT;
384	>	double r = (nextLong() >>> 11) * DOUBLE_ULP;
385		if (origin < bound) {
386		r = r * (bound - origin) + origin;
387		if (r >= bound) // correct for rounding
#	Line 442 | Line 400 | public class SplittableRandom {
400		* @param seed the initial seed
401		*/
402		public SplittableRandom(long seed) {
403	<	this(seed, 0L);
403	>	this(seed, GOLDEN_GAMMA);
404		}
405
406		/**
#	Line 451 | Line 409 | public class SplittableRandom {
409		* of those of any other instances in the current program; and
410		* may, and typically does, vary across program invocations.
411		*/
412	<	public SplittableRandom() {
413	<	this(nextDefaultSeed(), GAMMA_GAMMA);
412	>	public SplittableRandom() { // emulate defaultGen.split()
413	>	long s = defaultGen.getAndAdd(2*GOLDEN_GAMMA);
414	>	this.seed = mix64(s);
415	>	this.gamma = mixGamma(s + GOLDEN_GAMMA);
416		}
417
418		/**
#	Line 470 | Line 430 | public class SplittableRandom {
430		* @return the new SplittableRandom instance
431		*/
432		public SplittableRandom split() {
433	<	return new SplittableRandom(nextSeed(), nextSplit);
433	>	return new SplittableRandom(nextLong(), mixGamma(nextSeed()));
434		}
435
436		/**
#	Line 486 | Line 446 | public class SplittableRandom {
446		* Returns a pseudorandom {@code int} value between zero (inclusive)
447		* and the specified bound (exclusive).
448		*
449	<	* @param bound the bound on the random number to be returned.  Must be
490	<	*        positive.
449	>	* @param bound the upper bound (exclusive).  Must be positive.
450		* @return a pseudorandom {@code int} value between zero
451		*         (inclusive) and the bound (exclusive)
452	<	* @throws IllegalArgumentException if the bound is less than zero
452	>	* @throws IllegalArgumentException if {@code bound} is not positive
453		*/
454		public int nextInt(int bound) {
455		if (bound <= 0)
456	<	throw new IllegalArgumentException("bound must be positive");
456	>	throw new IllegalArgumentException(BadBound);
457		// Specialize internalNextInt for origin 0
458		int r = mix32(nextSeed());
459		int m = bound - 1;
#	Line 522 | Line 481 | public class SplittableRandom {
481		*/
482		public int nextInt(int origin, int bound) {
483		if (origin >= bound)
484	<	throw new IllegalArgumentException("bound must be greater than origin");
484	>	throw new IllegalArgumentException(BadRange);
485		return internalNextInt(origin, bound);
486		}
487
#	Line 539 | Line 498 | public class SplittableRandom {
498		* Returns a pseudorandom {@code long} value between zero (inclusive)
499		* and the specified bound (exclusive).
500		*
501	<	* @param bound the bound on the random number to be returned.  Must be
543	<	*        positive.
501	>	* @param bound the upper bound (exclusive).  Must be positive.
502		* @return a pseudorandom {@code long} value between zero
503		*         (inclusive) and the bound (exclusive)
504	<	* @throws IllegalArgumentException if {@code bound} is less than zero
504	>	* @throws IllegalArgumentException if {@code bound} is not positive
505		*/
506		public long nextLong(long bound) {
507		if (bound <= 0)
508	<	throw new IllegalArgumentException("bound must be positive");
508	>	throw new IllegalArgumentException(BadBound);
509		// Specialize internalNextLong for origin 0
510		long r = mix64(nextSeed());
511		long m = bound - 1;
#	Line 575 | Line 533 | public class SplittableRandom {
533		*/
534		public long nextLong(long origin, long bound) {
535		if (origin >= bound)
536	<	throw new IllegalArgumentException("bound must be greater than origin");
536	>	throw new IllegalArgumentException(BadRange);
537		return internalNextLong(origin, bound);
538		}
539
#	Line 584 | Line 542 | public class SplittableRandom {
542		* (inclusive) and one (exclusive).
543		*
544		* @return a pseudorandom {@code double} value between zero
545	<	* (inclusive) and one (exclusive)
545	>	*         (inclusive) and one (exclusive)
546		*/
547		public double nextDouble() {
548	<	return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT;
548	>	return (mix64(nextSeed()) >>> 11) * DOUBLE_ULP;
549		}
550
551		/**
552		* Returns a pseudorandom {@code double} value between 0.0
553		* (inclusive) and the specified bound (exclusive).
554		*
555	<	* @param bound the bound on the random number to be returned.  Must be
598	<	*        positive.
555	>	* @param bound the upper bound (exclusive).  Must be positive.
556		* @return a pseudorandom {@code double} value between zero
557		*         (inclusive) and the bound (exclusive)
558	<	* @throws IllegalArgumentException if {@code bound} is less than zero
558	>	* @throws IllegalArgumentException if {@code bound} is not positive
559		*/
560		public double nextDouble(double bound) {
561		if (!(bound > 0.0))
562	<	throw new IllegalArgumentException("bound must be positive");
563	<	double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
562	>	throw new IllegalArgumentException(BadBound);
563	>	double result = (mix64(nextSeed()) >>> 11) * DOUBLE_ULP * bound;
564		return (result < bound) ?  result : // correct for rounding
565		Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
566		}
#	Line 613 | Line 570 | public class SplittableRandom {
570		* origin (inclusive) and bound (exclusive).
571		*
572		* @param origin the least value returned
573	<	* @param bound the upper bound
573	>	* @param bound the upper bound (exclusive)
574		* @return a pseudorandom {@code double} value between the origin
575		*         (inclusive) and the bound (exclusive)
576		* @throws IllegalArgumentException if {@code origin} is greater than
#	Line 621 | Line 578 | public class SplittableRandom {
578		*/
579		public double nextDouble(double origin, double bound) {
580		if (!(origin < bound))
581	<	throw new IllegalArgumentException("bound must be greater than origin");
581	>	throw new IllegalArgumentException(BadRange);
582		return internalNextDouble(origin, bound);
583		}
584
#	Line 638 | Line 595 | public class SplittableRandom {
595		// maintenance purposes the small differences across forms.
596
597		/**
598	<	* Returns a stream producing the given {@code streamSize} number of
599	<	* pseudorandom {@code int} values.
598	>	* Returns a stream producing the given {@code streamSize} number
599	>	* of pseudorandom {@code int} values from this generator and/or
600	>	* one split from it.
601		*
602		* @param streamSize the number of values to generate
603		* @return a stream of pseudorandom {@code int} values
#	Line 648 | Line 606 | public class SplittableRandom {
606		*/
607		public IntStream ints(long streamSize) {
608		if (streamSize < 0L)
609	<	throw new IllegalArgumentException("negative Stream size");
609	>	throw new IllegalArgumentException(BadSize);
610		return StreamSupport.intStream
611		(new RandomIntsSpliterator
612		(this, 0L, streamSize, Integer.MAX_VALUE, 0),
#	Line 657 | Line 615 | public class SplittableRandom {
615
616		/**
617		* Returns an effectively unlimited stream of pseudorandom {@code int}
618	<	* values.
618	>	* values from this generator and/or one split from it.
619		*
620		* @implNote This method is implemented to be equivalent to {@code
621		* ints(Long.MAX_VALUE)}.
#	Line 672 | Line 630 | public class SplittableRandom {
630		}
631
632		/**
633	<	* Returns a stream producing the given {@code streamSize} number of
634	<	* pseudorandom {@code int} values, each conforming to the given
635	<	* origin and bound.
633	>	* Returns a stream producing the given {@code streamSize} number
634	>	* of pseudorandom {@code int} values from this generator and/or one split
635	>	* from it; each value conforms to the given origin (inclusive) and bound
636	>	* (exclusive).
637		*
638		* @param streamSize the number of values to generate
639	<	* @param randomNumberOrigin the origin of each random value
640	<	* @param randomNumberBound the bound of each random value
639	>	* @param randomNumberOrigin the origin (inclusive) of each random value
640	>	* @param randomNumberBound the bound (exclusive) of each random value
641		* @return a stream of pseudorandom {@code int} values,
642	<	*         each with the given origin and bound
642	>	*         each with the given origin (inclusive) and bound (exclusive)
643		* @throws IllegalArgumentException if {@code streamSize} is
644		*         less than zero, or {@code randomNumberOrigin}
645		*         is greater than or equal to {@code randomNumberBound}
#	Line 688 | Line 647 | public class SplittableRandom {
647		public IntStream ints(long streamSize, int randomNumberOrigin,
648		int randomNumberBound) {
649		if (streamSize < 0L)
650	<	throw new IllegalArgumentException("negative Stream size");
650	>	throw new IllegalArgumentException(BadSize);
651		if (randomNumberOrigin >= randomNumberBound)
652	<	throw new IllegalArgumentException("bound must be greater than origin");
652	>	throw new IllegalArgumentException(BadRange);
653		return StreamSupport.intStream
654		(new RandomIntsSpliterator
655		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 699 | Line 658 | public class SplittableRandom {
658
659		/**
660		* Returns an effectively unlimited stream of pseudorandom {@code
661	<	* int} values, each conforming to the given origin and bound.
661	>	* int} values from this generator and/or one split from it; each value
662	>	* conforms to the given origin (inclusive) and bound (exclusive).
663		*
664		* @implNote This method is implemented to be equivalent to {@code
665		* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
666		*
667	<	* @param randomNumberOrigin the origin of each random value
668	<	* @param randomNumberBound the bound of each random value
667	>	* @param randomNumberOrigin the origin (inclusive) of each random value
668	>	* @param randomNumberBound the bound (exclusive) of each random value
669		* @return a stream of pseudorandom {@code int} values,
670	<	*         each with the given origin and bound
670	>	*         each with the given origin (inclusive) and bound (exclusive)
671		* @throws IllegalArgumentException if {@code randomNumberOrigin}
672		*         is greater than or equal to {@code randomNumberBound}
673		*/
674		public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
675		if (randomNumberOrigin >= randomNumberBound)
676	<	throw new IllegalArgumentException("bound must be greater than origin");
676	>	throw new IllegalArgumentException(BadRange);
677		return StreamSupport.intStream
678		(new RandomIntsSpliterator
679		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 721 | Line 681 | public class SplittableRandom {
681		}
682
683		/**
684	<	* Returns a stream producing the given {@code streamSize} number of
685	<	* pseudorandom {@code long} values.
684	>	* Returns a stream producing the given {@code streamSize} number
685	>	* of pseudorandom {@code long} values from this generator and/or
686	>	* one split from it.
687		*
688		* @param streamSize the number of values to generate
689		* @return a stream of pseudorandom {@code long} values
#	Line 731 | Line 692 | public class SplittableRandom {
692		*/
693		public LongStream longs(long streamSize) {
694		if (streamSize < 0L)
695	<	throw new IllegalArgumentException("negative Stream size");
695	>	throw new IllegalArgumentException(BadSize);
696		return StreamSupport.longStream
697		(new RandomLongsSpliterator
698		(this, 0L, streamSize, Long.MAX_VALUE, 0L),
#	Line 739 | Line 700 | public class SplittableRandom {
700		}
701
702		/**
703	<	* Returns an effectively unlimited stream of pseudorandom {@code long}
704	<	* values.
703	>	* Returns an effectively unlimited stream of pseudorandom {@code
704	>	* long} values from this generator and/or one split from it.
705		*
706		* @implNote This method is implemented to be equivalent to {@code
707		* longs(Long.MAX_VALUE)}.
#	Line 756 | Line 717 | public class SplittableRandom {
717
718		/**
719		* Returns a stream producing the given {@code streamSize} number of
720	<	* pseudorandom {@code long} values, each conforming to the
721	<	* given origin and bound.
720	>	* pseudorandom {@code long} values from this generator and/or one split
721	>	* from it; each value conforms to the given origin (inclusive) and bound
722	>	* (exclusive).
723		*
724		* @param streamSize the number of values to generate
725	<	* @param randomNumberOrigin the origin of each random value
726	<	* @param randomNumberBound the bound of each random value
725	>	* @param randomNumberOrigin the origin (inclusive) of each random value
726	>	* @param randomNumberBound the bound (exclusive) of each random value
727		* @return a stream of pseudorandom {@code long} values,
728	<	*         each with the given origin and bound
728	>	*         each with the given origin (inclusive) and bound (exclusive)
729		* @throws IllegalArgumentException if {@code streamSize} is
730		*         less than zero, or {@code randomNumberOrigin}
731		*         is greater than or equal to {@code randomNumberBound}
#	Line 771 | Line 733 | public class SplittableRandom {
733		public LongStream longs(long streamSize, long randomNumberOrigin,
734		long randomNumberBound) {
735		if (streamSize < 0L)
736	<	throw new IllegalArgumentException("negative Stream size");
736	>	throw new IllegalArgumentException(BadSize);
737		if (randomNumberOrigin >= randomNumberBound)
738	<	throw new IllegalArgumentException("bound must be greater than origin");
738	>	throw new IllegalArgumentException(BadRange);
739		return StreamSupport.longStream
740		(new RandomLongsSpliterator
741		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 782 | Line 744 | public class SplittableRandom {
744
745		/**
746		* Returns an effectively unlimited stream of pseudorandom {@code
747	<	* long} values, each conforming to the given origin and bound.
747	>	* long} values from this generator and/or one split from it; each value
748	>	* conforms to the given origin (inclusive) and bound (exclusive).
749		*
750		* @implNote This method is implemented to be equivalent to {@code
751		* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
752		*
753	<	* @param randomNumberOrigin the origin of each random value
754	<	* @param randomNumberBound the bound of each random value
753	>	* @param randomNumberOrigin the origin (inclusive) of each random value
754	>	* @param randomNumberBound the bound (exclusive) of each random value
755		* @return a stream of pseudorandom {@code long} values,
756	<	*         each with the given origin and bound
756	>	*         each with the given origin (inclusive) and bound (exclusive)
757		* @throws IllegalArgumentException if {@code randomNumberOrigin}
758		*         is greater than or equal to {@code randomNumberBound}
759		*/
760		public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
761		if (randomNumberOrigin >= randomNumberBound)
762	<	throw new IllegalArgumentException("bound must be greater than origin");
762	>	throw new IllegalArgumentException(BadRange);
763		return StreamSupport.longStream
764		(new RandomLongsSpliterator
765		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 805 | Line 768 | public class SplittableRandom {
768
769		/**
770		* Returns a stream producing the given {@code streamSize} number of
771	<	* pseudorandom {@code double} values, each between zero
772	<	* (inclusive) and one (exclusive).
771	>	* pseudorandom {@code double} values from this generator and/or one split
772	>	* from it; each value is between zero (inclusive) and one (exclusive).
773		*
774		* @param streamSize the number of values to generate
775		* @return a stream of {@code double} values
#	Line 815 | Line 778 | public class SplittableRandom {
778		*/
779		public DoubleStream doubles(long streamSize) {
780		if (streamSize < 0L)
781	<	throw new IllegalArgumentException("negative Stream size");
781	>	throw new IllegalArgumentException(BadSize);
782		return StreamSupport.doubleStream
783		(new RandomDoublesSpliterator
784		(this, 0L, streamSize, Double.MAX_VALUE, 0.0),
#	Line 824 | Line 787 | public class SplittableRandom {
787
788		/**
789		* Returns an effectively unlimited stream of pseudorandom {@code
790	<	* double} values, each between zero (inclusive) and one
791	<	* (exclusive).
790	>	* double} values from this generator and/or one split from it; each value
791	>	* is between zero (inclusive) and one (exclusive).
792		*
793		* @implNote This method is implemented to be equivalent to {@code
794		* doubles(Long.MAX_VALUE)}.
#	Line 841 | Line 804 | public class SplittableRandom {
804
805		/**
806		* Returns a stream producing the given {@code streamSize} number of
807	<	* pseudorandom {@code double} values, each conforming to the
808	<	* given origin and bound.
807	>	* pseudorandom {@code double} values from this generator and/or one split
808	>	* from it; each value conforms to the given origin (inclusive) and bound
809	>	* (exclusive).
810		*
811		* @param streamSize the number of values to generate
812	<	* @param randomNumberOrigin the origin of each random value
813	<	* @param randomNumberBound the bound of each random value
812	>	* @param randomNumberOrigin the origin (inclusive) of each random value
813	>	* @param randomNumberBound the bound (exclusive) of each random value
814		* @return a stream of pseudorandom {@code double} values,
815	<	* each with the given origin and bound
815	>	*         each with the given origin (inclusive) and bound (exclusive)
816		* @throws IllegalArgumentException if {@code streamSize} is
817	<	* less than zero
817	>	*         less than zero
818		* @throws IllegalArgumentException if {@code randomNumberOrigin}
819		*         is greater than or equal to {@code randomNumberBound}
820		*/
821		public DoubleStream doubles(long streamSize, double randomNumberOrigin,
822		double randomNumberBound) {
823		if (streamSize < 0L)
824	<	throw new IllegalArgumentException("negative Stream size");
824	>	throw new IllegalArgumentException(BadSize);
825		if (!(randomNumberOrigin < randomNumberBound))
826	<	throw new IllegalArgumentException("bound must be greater than origin");
826	>	throw new IllegalArgumentException(BadRange);
827		return StreamSupport.doubleStream
828		(new RandomDoublesSpliterator
829		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 868 | Line 832 | public class SplittableRandom {
832
833		/**
834		* Returns an effectively unlimited stream of pseudorandom {@code
835	<	* double} values, each conforming to the given origin and bound.
835	>	* double} values from this generator and/or one split from it; each value
836	>	* conforms to the given origin (inclusive) and bound (exclusive).
837		*
838		* @implNote This method is implemented to be equivalent to {@code
839		* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
840		*
841	<	* @param randomNumberOrigin the origin of each random value
842	<	* @param randomNumberBound the bound of each random value
841	>	* @param randomNumberOrigin the origin (inclusive) of each random value
842	>	* @param randomNumberBound the bound (exclusive) of each random value
843		* @return a stream of pseudorandom {@code double} values,
844	<	* each with the given origin and bound
844	>	*         each with the given origin (inclusive) and bound (exclusive)
845		* @throws IllegalArgumentException if {@code randomNumberOrigin}
846		*         is greater than or equal to {@code randomNumberBound}
847		*/
848		public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
849		if (!(randomNumberOrigin < randomNumberBound))
850	<	throw new IllegalArgumentException("bound must be greater than origin");
850	>	throw new IllegalArgumentException(BadRange);
851		return StreamSupport.doubleStream
852		(new RandomDoublesSpliterator
853		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 940 | Line 905 | public class SplittableRandom {
905		long i = index, f = fence;
906		if (i < f) {
907		index = f;
908	+	SplittableRandom r = rng;
909		int o = origin, b = bound;
910		do {
911	<	consumer.accept(rng.internalNextInt(o, b));
911	>	consumer.accept(r.internalNextInt(o, b));
912		} while (++i < f);
913		}
914		}
#	Line 994 | Line 960 | public class SplittableRandom {
960		long i = index, f = fence;
961		if (i < f) {
962		index = f;
963	+	SplittableRandom r = rng;
964		long o = origin, b = bound;
965		do {
966	<	consumer.accept(rng.internalNextLong(o, b));
966	>	consumer.accept(r.internalNextLong(o, b));
967		} while (++i < f);
968		}
969		}
#	Line 1049 | Line 1016 | public class SplittableRandom {
1016		long i = index, f = fence;
1017		if (i < f) {
1018		index = f;
1019	+	SplittableRandom r = rng;
1020		double o = origin, b = bound;
1021		do {
1022	<	consumer.accept(rng.internalNextDouble(o, b));
1022	>	consumer.accept(r.internalNextDouble(o, b));
1023		} while (++i < f);
1024		}
1025		}

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