8266552: Technical corrections to java/util/random/package-info.java
Reviewed-by: darcy
This commit is contained in:
Jim Laskey
parent
e14b026841
commit
b4371e9bca
src
java.base/share/classes/java/util/random
jdk.random/share/classes/jdk/random
@ -128,24 +128,27 @@
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* <h2>Choosing a Random Number Generator Algorithm</h2>
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*
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* <p> There are three groups of random number generator algorithm provided
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* in Java; Legacy group, LXM group and Xoroshiro/Xoshiro group.
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* in Java: the Legacy group, the LXM group, and the Xoroshiro/Xoshiro group.
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*
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* <p> The legacy group includes random number generators that existed
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* before JDK 17; Random, ThreadLocalRandom, SplittableRandom and
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* SecureRandom. Random (LCG) is the weakest of available algorithms and it
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* before JDK 17: Random, ThreadLocalRandom, SplittableRandom, and
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* SecureRandom. Random (LCG) is the weakest of the available algorithms, and it
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* is recommended that users migrate to newer algorithms. If an application
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* requires a random number generator algorithm that is cryptographically
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* secure, then it should continue to use an instance of the class {@link
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* java.security.SecureRandom}.
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*
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* <p> The algorithms in the LXM group use a similar algorithm. The parameters
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* of the algorithm can be found in algorithm name. The numbers indicate the
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* number of bits in the lower and upper state bits respectively. Mix indicates
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* the algorithm uses mix congruency. StarStar indicates use a double
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* multiplier.
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* <p> The algorithms in the LXM group are similar to each other. The parameters
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* of each algorithm can be found in the algorithm name. The number after "L" indicates the
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* number of state bits for the LCG subgenerator, and the number after "X" indicates the
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* number of state bits for the XBG subgenerator. "Mix" indicates that
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* the algorithm uses an 8-operation bit-mixing function; "StarStar" indicates use
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* of a 3-operation bit-scrambler.
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*
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* <p> The algorithms in the Xoroshiro/Xoshiro are more traditional algorithms
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* where the number in the name indicates the period.
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* <p> The algorithms in the Xoroshiro/Xoshiro group are more traditional algorithms
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* (see David Blackman and Sebastiano Vigna, "Scrambled Linear Pseudorandom
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* Number Generators," ACM Transactions on Mathematical Software, 2021);
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* the number in the name indicates the number of state bits.
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*
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* <p> For applications (such as physical simulation, machine learning, and
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* games) that do not require a cryptographically secure algorithm, this package
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@ -209,7 +212,7 @@
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*
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* These algorithms [in the table below] must be found with the current version
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* of Java SE. A particular JDK implementation may recognize additional
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* algorithms; check the JDK's documentation for details. The set of algorithm
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* algorithms; check the JDK's documentation for details. The set of algorithms
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* required by Java SE may be updated by changes to the Java SE specification.
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* Over time, new algorithms may be added and old algorithms may be removed.
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* <p>In addition, as another life-cycle phase, an algorithm may be {@linkplain
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@ -235,7 +238,7 @@
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* <tr>
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* <td style="text-align:left">L128X1024MixRandom</td>
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* <td style="text-align:left">LXM</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(N*64).subtract(BigInteger.ONE).shiftLeft(128)</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(1024).subtract(BigInteger.ONE).shiftLeft(128)</td>
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* <td style="text-align:right">1152</td>
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* <td style="text-align:right">1</td>
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* </tr>
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@ -263,7 +266,7 @@
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* <tr>
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* <td style="text-align:left">L64X1024MixRandom</td>
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* <td style="text-align:left">LXM</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(N*64).subtract(BigInteger.ONE).shiftLeft(64)</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(1024).subtract(BigInteger.ONE).shiftLeft(64)</td>
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* <td style="text-align:right">1088</td>
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* <td style="text-align:right">16</td>
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* </tr>
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@ -272,14 +275,14 @@
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* <td style="text-align:left">LXM</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(128).subtract(BigInteger.ONE).shiftLeft(64)</td>
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* <td style="text-align:right">192</td>
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* <td style="text-align:right">1</td>
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* <td style="text-align:right">2</td>
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* </tr>
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* <tr>
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* <td style="text-align:left">L64X128StarStarRandom</td>
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* <td style="text-align:left">LXM</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(128).subtract(BigInteger.ONE).shiftLeft(64)</td>
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* <td style="text-align:right">192</td>
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* <td style="text-align:right">1</td>
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* <td style="text-align:right">2</td>
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* </tr>
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* <tr>
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* <td style="text-align:left">L64X256MixRandom</td>
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@ -314,14 +317,14 @@
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* <td style="text-align:left">Xoroshiro</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(128).subtract(BigInteger.ONE)</td>
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* <td style="text-align:right">128</td>
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* <td style="text-align:right">2</td>
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* <td style="text-align:right">1</td>
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* </tr>
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* <tr>
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* <td style="text-align:left">Xoshiro256PlusPlus</td>
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* <td style="text-align:left">Xoshiro</td>
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* <td style="text-align:left">BigInteger.ONE.shiftLeft(256).subtract(BigInteger.ONE)</td>
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* <td style="text-align:right">256</td>
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* <td style="text-align:right">4</td>
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* <td style="text-align:right">3</td>
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* </tr>
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* </tbody>
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* </table>
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@ -373,27 +376,29 @@
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*
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* The structure of the central nextLong (or nextInt) method of an LXM
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* algorithm follows a suggestion in December 2017 by Sebastiano Vigna
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* that using one LCG subgenerator and one xor-based subgenerator (rather
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* than two LCG subgenerators) would provide a longer period, superior
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* that using one Linear Congruential Generator (LCG) as a first subgenerator
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* and one Xor-Based Generator (XBG) as a second subgenerator (rather
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* than using two LCG subgenerators) would provide a longer period, superior
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* equidistribution, scalability, and better quality. Each of the
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* specific implementations here combines one of the best currently known
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* xor-based generators (xoroshiro or xoshiro, described by Blackman and
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* Vigna in "Scrambled Linear Pseudorandom Number Generators", ACM
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* Trans. Math. Softw., 2021) with an LCG that uses one of the best
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* XBG algorithms (xoroshiro128 or xoshiro256, described by Blackman and
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* Vigna in "Scrambled Linear Pseudorandom Number Generators", ACM Transactions
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* on Mathematical Software, 2021) with an LCG that uses one of the best
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* currently known multipliers (found by a search for better multipliers
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* in 2019 by Steele and Vigna), and then applies a mixing function
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* identified by Doug Lea. Testing has confirmed that the LXM algorithm
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* is far superior in quality to the SplitMix algorithm (2014) used by
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* SplittableRandom.
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* in 2019 by Steele and Vigna), and then applies either a mixing function
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* identified by Doug Lea or a simple scrambler proposed by Blackman and Vigna.
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* Testing has confirmed that the LXM algorithm is far superior in quality to
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* the SplitMix algorithm (2014) used by {@code SplittableRandom}.
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*
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* Each class with a name of the form {@code L}<i>p</i>{@code X}<i>q</i>{@code
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* SomethingRandom} uses some specific member of the LXM family of random number
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* algorithms; "LXM" is short for "LCG, Xorshift, Mixing function". Every LXM
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* generator consists of two subgenerators; one is an LCG (Linear Congruential
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* Generator) and the other is an Xorshift generator. Each output of an LXM
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* Each class with a name of the form
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* {@code L}<i>p</i>{@code X}<i>q</i>{@code SomethingRandom}
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* uses some specific member of the LXM family of random number
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* algorithms; "LXM" is short for "LCG, XBG, Mixer". Every LXM
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* generator has two subgenerators; one is an LCG (Linear Congruential
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* Generator) and the other is an XBG (Xor-Based Generator). Each output of an LXM
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* generator is the result of combining state from the LCG with state from the
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* Xorshift generator by using a Mixing function (and then the state of the LCG
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* and the state of the Xorshift generator are advanced).
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* XBG using a Mixing function (and then the state of the LCG
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* and the state of the XBG are advanced).
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*
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* <p> The LCG subgenerator has an update step of the form {@code s = m*s + a},
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* where {@code s}, {@code m}, and {@code a} are all binary integers of the same
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@ -406,10 +411,11 @@
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* {@code s} is 128 bits, then we use the name "{@code sh}" below to refer to
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* the high half of {@code s}, that is, the high-order 64 bits of {@code s}.)
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*
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* <p> The Xorshift subgenerator can in principle be any one of a wide variety
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* of xorshift algorithms; in this package it is always either
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* <p> The XBG subgenerator can in principle be any one of a wide variety
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* of XBG algorithms; in this package it is always either
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* {@code xoroshiro128}, {@code xoshiro256}, or {@code xoroshiro1024}, in each
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* case without any final scrambler such as "+" or "**". Its state consists of
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* case without any final scrambler (such as "+" or "**") because LXM uses
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* a separate Mixer later in the process. The XBG state consists of
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* some fixed number of {@code int} or {@code long} fields, generally named
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* {@code x0}, {@code x1}, and so on, which can take on any values provided that
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* they are not all zero. The collective total size of these fields is <i>q</i>
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@ -427,7 +433,7 @@
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*
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* <p> Generally speaking, among the "{@code L}<i>p</i>{@code X}<i>q</i>"
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* generators, the memory required for an instance is 2<i>p</i>+<i>q</i> bits.
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* (If <i>q</i> is 1024 or larger, the Xorshift state is represented as an
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* (If <i>q</i> is 1024 or larger, the XBG state is represented as an
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* array, so additional bits are needed for the array object header, and another
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* 32 bits are used for an array index.)
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*
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@ -545,7 +551,7 @@
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* 2<sup>64</sup>(2<sup>256</sup>−1) such subsequences, and each
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* subsequence, which consists of 4 64-bit values, can have one of
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* 2<sup>256</sup> values. Of those 2<sup>256</sup> subsequence values, nearly
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* all of them (2<sup>256</sup>%minus;2<sup>64</sup>) occur 2<sup>64</sup> times
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* all of them (2<sup>256</sup>−2<sup>64</sup>) occur 2<sup>64</sup> times
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* over the course of the entire cycle, and the other 2<sup>64</sup> subsequence
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* values occur only 2<sup>64</sup>−1 times. So the ratio of the
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* probability of getting any specific one of the less common subsequence values
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@ -560,7 +566,7 @@
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* 4-equidistributed (but not exactly 4-equidistributed).
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*
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* <p> The next table gives the LCG multiplier value, the name of the specific
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* Xorshift algorithm used, the specific numeric parameters for that Xorshift
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* XBG algorithm used, the specific numeric parameters for that XBG
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* algorithm, and the mixing function for each of the specific LXM algorithms
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* used in this package. (Note that the multiplier used for the 128-bit LCG
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* cases is 65 bits wide, so the constant {@code 0x1d605bbb58c8abbfdL} shown in
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@ -574,8 +580,8 @@
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* <thead>
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* <tr><th style="text-align:left">Implementation</th>
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* <th style="text-align:right">LCG multiplier {@code m}</th>
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* <th style="text-align:left">Xorshift algorithm</th>
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* <th style="text-align:left">Xorshift parameters</th>
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* <th style="text-align:left">XBG algorithm</th>
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* <th style="text-align:left">XBG parameters</th>
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* <th style="text-align:left">Mixing function</th></tr>
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* </thead>
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* <tbody>
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@ -146,7 +146,7 @@ public final class L128X1024MixRandom extends AbstractSplittableWithBrineGenerat
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private final long ah, al;
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/**
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* The per-instance state: sh and sl for the LCG; the array x for the xorshift;
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* The per-instance state: sh and sl for the LCG; the array x for the XBG;
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* p is the rotating pointer into the array x.
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* At least one of the 16 elements of the array x must be nonzero.
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*/
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@ -165,22 +165,22 @@ public final class L128X1024MixRandom extends AbstractSplittableWithBrineGenerat
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* @param al low half of the additive parameter for the LCG
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* @param sh high half of the initial state for the LCG
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* @param sl low half of the initial state for the LCG
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* @param x0 first word of the initial state for the xorshift generator
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* @param x1 second word of the initial state for the xorshift generator
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* @param x2 third word of the initial state for the xorshift generator
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* @param x3 fourth word of the initial state for the xorshift generator
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* @param x4 fifth word of the initial state for the xorshift generator
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* @param x5 sixth word of the initial state for the xorshift generator
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* @param x6 seventh word of the initial state for the xorshift generator
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* @param x7 eight word of the initial state for the xorshift generator
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* @param x8 ninth word of the initial state for the xorshift generator
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* @param x9 tenth word of the initial state for the xorshift generator
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* @param x10 eleventh word of the initial state for the xorshift generator
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* @param x11 twelfth word of the initial state for the xorshift generator
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* @param x12 thirteenth word of the initial state for the xorshift generator
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* @param x13 fourteenth word of the initial state for the xorshift generator
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* @param x14 fifteenth word of the initial state for the xorshift generator
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* @param x15 sixteenth word of the initial state for the xorshift generator
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* @param x0 first word of the initial state for the XBG
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* @param x1 second word of the initial state for the XBG
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* @param x2 third word of the initial state for the XBG
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* @param x3 fourth word of the initial state for the XBG
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* @param x4 fifth word of the initial state for the XBG
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* @param x5 sixth word of the initial state for the XBG
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* @param x6 seventh word of the initial state for the XBG
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* @param x7 eight word of the initial state for the XBG
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* @param x8 ninth word of the initial state for the XBG
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* @param x9 tenth word of the initial state for the XBG
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* @param x10 eleventh word of the initial state for the XBG
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* @param x11 twelfth word of the initial state for the XBG
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* @param x12 thirteenth word of the initial state for the XBG
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* @param x13 fourteenth word of the initial state for the XBG
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* @param x14 fifteenth word of the initial state for the XBG
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* @param x15 sixteenth word of the initial state for the XBG
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*/
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public L128X1024MixRandom(long ah, long al, long sh, long sl,
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long x0, long x1, long x2, long x3,
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@ -136,7 +136,7 @@ public final class L128X128MixRandom extends AbstractSplittableWithBrineGenerato
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private final long ah, al;
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/**
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* The per-instance state: sh and sl for the LCG; x0 and x1 for the xorshift.
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* The per-instance state: sh and sl for the LCG; x0 and x1 for the XBG.
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* At least one of x0 and x1 must be nonzero.
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*/
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private long sh, sl, x0, x1;
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@ -152,8 +152,8 @@ public final class L128X128MixRandom extends AbstractSplittableWithBrineGenerato
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* @param al low half of the additive parameter for the LCG
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* @param sh high half of the initial state for the LCG
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* @param sl low half of the initial state for the LCG
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* @param x0 first word of the initial state for the xorshift generator
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* @param x1 second word of the initial state for the xorshift generator
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* @param x0 first word of the initial state for the XBG
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* @param x1 second word of the initial state for the XBG
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*/
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public L128X128MixRandom(long ah, long al, long sh, long sl, long x0, long x1) {
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// Force a to be odd.
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@ -262,7 +262,7 @@ public final class L128X128MixRandom extends AbstractSplittableWithBrineGenerato
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if (Long.compareUnsigned(sl, u) < 0) ++sh; // Handle the carry propagation from low half to high half.
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long q0 = x0, q1 = x1;
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// Update the Xorshift subgenerator
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// Update the XBG subgenerator
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{ // xoroshiro128v1_0
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q1 ^= q0;
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q0 = Long.rotateLeft(q0, 24);
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@ -145,7 +145,7 @@ public final class L128X256MixRandom extends AbstractSplittableWithBrineGenerato
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private final long ah, al;
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/**
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* The per-instance state: sh and sl for the LCG; x0, x1, x2, and x3 for the xorshift.
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* The per-instance state: sh and sl for the LCG; x0, x1, x2, and x3 for the XBG.
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* At least one of the four fields x0, x1, x2, and x3 must be nonzero.
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*/
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private long sh, sl, x0, x1, x2, x3;
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@ -161,10 +161,10 @@ public final class L128X256MixRandom extends AbstractSplittableWithBrineGenerato
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* @param al low half of the additive parameter for the LCG
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* @param sh high half of the initial state for the LCG
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* @param sl low half of the initial state for the LCG
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* @param x0 first word of the initial state for the xorshift generator
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* @param x1 second word of the initial state for the xorshift generator
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* @param x2 third word of the initial state for the xorshift generator
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* @param x3 fourth word of the initial state for the xorshift generator
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* @param x0 first word of the initial state for the XBG
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* @param x1 second word of the initial state for the XBG
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* @param x2 third word of the initial state for the XBG
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* @param x3 fourth word of the initial state for the XBG
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*/
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public L128X256MixRandom(long ah, long al, long sh, long sl, long x0, long x1, long x2, long x3) {
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// Force a to be odd.
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@ -282,7 +282,7 @@ public final class L128X256MixRandom extends AbstractSplittableWithBrineGenerato
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sl = u + al;
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if (Long.compareUnsigned(sl, u) < 0) ++sh; // Handle the carry propagation from low half to high half.
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// Update the Xorshift subgenerator
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// Update the XBG subgenerator
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long q0 = x0, q1 = x1, q2 = x2, q3 = x3;
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{ // xoshiro256 1.0
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long t = q1 << 17;
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@ -134,7 +134,7 @@ public final class L32X64MixRandom extends AbstractSplittableWithBrineGenerator
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private final int a;
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/**
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* The per-instance state: s for the LCG; x0 and x1 for the xorshift.
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* The per-instance state: s for the LCG; x0 and x1 for the XBG.
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* At least one of x0 and x1 must be nonzero.
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*/
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private int s, x0, x1;
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@ -148,8 +148,8 @@ public final class L32X64MixRandom extends AbstractSplittableWithBrineGenerator
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*
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* @param a additive parameter for the LCG
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* @param s initial state for the LCG
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* @param x0 first word of the initial state for the xorshift generator
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* @param x1 second word of the initial state for the xorshift generator
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* @param x0 first word of the initial state for the XBG
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* @param x1 second word of the initial state for the XBG
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*/
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public L32X64MixRandom(int a, int s, int x0, int x1) {
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// Force a to be odd.
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@ -235,7 +235,7 @@ public final class L32X64MixRandom extends AbstractSplittableWithBrineGenerator
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// Update the LCG subgenerator
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s = M * s + a;
|
||||
|
||||
// Update the Xorshift subgenerator
|
||||
// Update the XBG subgenerator
|
||||
int q0 = x0, q1 = x1;
|
||||
{ // xoroshiro64
|
||||
q1 ^= q0;
|
||||
|
||||
@ -141,7 +141,7 @@ public final class L64X1024MixRandom extends AbstractSplittableWithBrineGenerato
|
||||
private final long a;
|
||||
|
||||
/**
|
||||
* The per-instance state: s for the LCG; the array x for the xorshift;
|
||||
* The per-instance state: s for the LCG; the array x for the XBG;
|
||||
* p is the rotating pointer into the array x.
|
||||
* At least one of the 16 elements of the array x must be nonzero.
|
||||
*/
|
||||
@ -158,22 +158,22 @@ public final class L64X1024MixRandom extends AbstractSplittableWithBrineGenerato
|
||||
*
|
||||
* @param a additive parameter for the LCG
|
||||
* @param s initial state for the LCG
|
||||
* @param x0 first word of the initial state for the xorshift generator
|
||||
* @param x1 second word of the initial state for the xorshift generator
|
||||
* @param x2 third word of the initial state for the xorshift generator
|
||||
* @param x3 fourth word of the initial state for the xorshift generator
|
||||
* @param x4 fifth word of the initial state for the xorshift generator
|
||||
* @param x5 sixth word of the initial state for the xorshift generator
|
||||
* @param x6 seventh word of the initial state for the xorshift generator
|
||||
* @param x7 eight word of the initial state for the xorshift generator
|
||||
* @param x8 ninth word of the initial state for the xorshift generator
|
||||
* @param x9 tenth word of the initial state for the xorshift generator
|
||||
* @param x10 eleventh word of the initial state for the xorshift generator
|
||||
* @param x11 twelfth word of the initial state for the xorshift generator
|
||||
* @param x12 thirteenth word of the initial state for the xorshift generator
|
||||
* @param x13 fourteenth word of the initial state for the xorshift generator
|
||||
* @param x14 fifteenth word of the initial state for the xorshift generator
|
||||
* @param x15 sixteenth word of the initial state for the xorshift generator
|
||||
* @param x0 first word of the initial state for the XBG
|
||||
* @param x1 second word of the initial state for the XBG
|
||||
* @param x2 third word of the initial state for the XBG
|
||||
* @param x3 fourth word of the initial state for the XBG
|
||||
* @param x4 fifth word of the initial state for the XBG
|
||||
* @param x5 sixth word of the initial state for the XBG
|
||||
* @param x6 seventh word of the initial state for the XBG
|
||||
* @param x7 eight word of the initial state for the XBG
|
||||
* @param x8 ninth word of the initial state for the XBG
|
||||
* @param x9 tenth word of the initial state for the XBG
|
||||
* @param x10 eleventh word of the initial state for the XBG
|
||||
* @param x11 twelfth word of the initial state for the XBG
|
||||
* @param x12 thirteenth word of the initial state for the XBG
|
||||
* @param x13 fourteenth word of the initial state for the XBG
|
||||
* @param x14 fifteenth word of the initial state for the XBG
|
||||
* @param x15 sixteenth word of the initial state for the XBG
|
||||
*/
|
||||
public L64X1024MixRandom(long a, long s,
|
||||
long x0, long x1, long x2, long x3,
|
||||
|
||||
@ -79,7 +79,7 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
name = "L64X128MixRandom",
|
||||
group = "LXM",
|
||||
i = 128, j = 1, k = 64,
|
||||
equidistribution = 1
|
||||
equidistribution = 2
|
||||
)
|
||||
public final class L64X128MixRandom extends AbstractSplittableWithBrineGenerator {
|
||||
|
||||
@ -135,7 +135,7 @@ public final class L64X128MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
private final long a;
|
||||
|
||||
/**
|
||||
* The per-instance state: s for the LCG; x0 and x1 for the xorshift.
|
||||
* The per-instance state: s for the LCG; x0 and x1 for the XBG.
|
||||
* At least one of x0 and x1 must be nonzero.
|
||||
*/
|
||||
private long s, x0, x1;
|
||||
@ -149,8 +149,8 @@ public final class L64X128MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
*
|
||||
* @param a additive parameter for the LCG
|
||||
* @param s initial state for the LCG
|
||||
* @param x0 first word of the initial state for the xorshift generator
|
||||
* @param x1 second word of the initial state for the xorshift generator
|
||||
* @param x0 first word of the initial state for the XBG
|
||||
* @param x1 second word of the initial state for the XBG
|
||||
*/
|
||||
public L64X128MixRandom(long a, long s, long x0, long x1) {
|
||||
// Force a to be odd.
|
||||
@ -238,7 +238,7 @@ public final class L64X128MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
// Update the LCG subgenerator
|
||||
s = M * s + a;
|
||||
|
||||
// Update the Xorshift subgenerator
|
||||
// Update the XBG subgenerator
|
||||
long q0 = x0, q1 = x1;
|
||||
{ // xoroshiro128v1_0
|
||||
q1 ^= q0;
|
||||
|
||||
@ -79,7 +79,7 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
name = "L64X128StarStarRandom",
|
||||
group = "LXM",
|
||||
i = 128, j = 1, k = 64,
|
||||
equidistribution = 1
|
||||
equidistribution = 2
|
||||
)
|
||||
public final class L64X128StarStarRandom extends AbstractSplittableWithBrineGenerator {
|
||||
|
||||
@ -135,7 +135,7 @@ public final class L64X128StarStarRandom extends AbstractSplittableWithBrineGene
|
||||
private final long a;
|
||||
|
||||
/**
|
||||
* The per-instance state: s for the LCG; x0 and x1 for the xorshift.
|
||||
* The per-instance state: s for the LCG; x0 and x1 for the XBG.
|
||||
* At least one of x0 and x1 must be nonzero.
|
||||
*/
|
||||
private long s, x0, x1;
|
||||
@ -149,8 +149,8 @@ public final class L64X128StarStarRandom extends AbstractSplittableWithBrineGene
|
||||
*
|
||||
* @param a additive parameter for the LCG
|
||||
* @param s initial state for the LCG
|
||||
* @param x0 first word of the initial state for the xorshift generator
|
||||
* @param x1 second word of the initial state for the xorshift generator
|
||||
* @param x0 first word of the initial state for the XBG
|
||||
* @param x1 second word of the initial state for the XBG
|
||||
*/
|
||||
public L64X128StarStarRandom(long a, long s, long x0, long x1) {
|
||||
// Force a to be odd.
|
||||
@ -238,7 +238,7 @@ public final class L64X128StarStarRandom extends AbstractSplittableWithBrineGene
|
||||
// Update the LCG subgenerator
|
||||
s = M * s + a;
|
||||
|
||||
// Update the Xorshift subgenerator
|
||||
// Update the XBG subgenerator
|
||||
long q0 = x0, q1 = x1;
|
||||
{ // xoroshiro128v1_0
|
||||
q1 ^= q0;
|
||||
|
||||
@ -136,7 +136,7 @@ public final class L64X256MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
private final long a;
|
||||
|
||||
/**
|
||||
* The per-instance state: s for the LCG; x0, x1, x2, and x3 for the xorshift.
|
||||
* The per-instance state: s for the LCG; x0, x1, x2, and x3 for the XBG.
|
||||
* At least one of the four fields x0, x1, x2, and x3 must be nonzero.
|
||||
*/
|
||||
private long s, x0, x1, x2, x3;
|
||||
@ -150,10 +150,10 @@ public final class L64X256MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
*
|
||||
* @param a additive parameter for the LCG
|
||||
* @param s initial state for the LCG
|
||||
* @param x0 first word of the initial state for the xorshift generator
|
||||
* @param x1 second word of the initial state for the xorshift generator
|
||||
* @param x2 third word of the initial state for the xorshift generator
|
||||
* @param x3 fourth word of the initial state for the xorshift generator
|
||||
* @param x0 first word of the initial state for the XBG
|
||||
* @param x1 second word of the initial state for the XBG
|
||||
* @param x2 third word of the initial state for the XBG
|
||||
* @param x3 fourth word of the initial state for the XBG
|
||||
*/
|
||||
public L64X256MixRandom(long a, long s, long x0, long x1, long x2, long x3) {
|
||||
// Force a to be odd.
|
||||
@ -250,7 +250,7 @@ public final class L64X256MixRandom extends AbstractSplittableWithBrineGenerator
|
||||
// Update the LCG subgenerator
|
||||
s = M * s + a;
|
||||
|
||||
// Update the Xorshift subgenerator
|
||||
// Update the XBG subgenerator
|
||||
long q0 = x0, q1 = x1, q2 = x2, q3 = x3;
|
||||
{ // xoshiro256 1.0
|
||||
long t = q1 << 17;
|
||||
|
||||
@ -43,6 +43,8 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
* The class {@link Xoroshiro128PlusPlus} uses the {@code xoroshiro128} algorithm
|
||||
* (parameters 49, 21, 28) with the "++" scrambler that computes
|
||||
* {@code Long.rotateLeft(s0 + s1, 17) + s0}.
|
||||
* (See David Blackman and Sebastiano Vigna, "Scrambled Linear Pseudorandom
|
||||
* Number Generators," ACM Transactions on Mathematical Software, 2021.)
|
||||
* Its state consists of two {@code long} fields {@code x0} and {@code x1},
|
||||
* which can take on any values provided that they are not both zero.
|
||||
* The period of this generator is 2<sup>128</sup>-1.
|
||||
@ -74,7 +76,7 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
name = "Xoroshiro128PlusPlus",
|
||||
group = "Xoroshiro",
|
||||
i = 128, j = 1, k = 0,
|
||||
equidistribution = 2
|
||||
equidistribution = 1
|
||||
)
|
||||
public final class Xoroshiro128PlusPlus implements LeapableGenerator {
|
||||
|
||||
@ -83,16 +85,6 @@ public final class Xoroshiro128PlusPlus implements LeapableGenerator {
|
||||
*
|
||||
* This is an implementation of the xoroshiro128++ algorithm version 1.0,
|
||||
* written in 2019 by David Blackman and Sebastiano Vigna (vigna@acm.org).
|
||||
* See http://xoshiro.di.unimi.it and these two papers:
|
||||
*
|
||||
* Sebastiano Vigna. 2016. An Experimental Exploration of Marsaglia's
|
||||
* xorshift Generators, Scrambled. ACM Transactions on Mathematical
|
||||
* Software 42, 4, Article 30 (June 2016), 23 pages.
|
||||
* https://doi.org/10.1145/2845077
|
||||
*
|
||||
* David Blackman and Sebastiano Vigna. 2018. Scrambled Linear
|
||||
* Pseudorandom Number Generators. Computing Research Repository (CoRR).
|
||||
* http://arxiv.org/abs/1805.01407
|
||||
*
|
||||
* The jump operation moves the current generator forward by 2*64
|
||||
* steps; this has the same effect as calling nextLong() 2**64
|
||||
|
||||
@ -57,6 +57,8 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
* The class {@link Xoshiro256PlusPlus} uses the {@code xoshiro256} algorithm,
|
||||
* version 1.0 (parameters 17, 45), with the "++" scrambler that computes
|
||||
* {@code Long.rotateLeft(s0 + s3, 23) + s0}.
|
||||
* (See David Blackman and Sebastiano Vigna, "Scrambled Linear Pseudorandom
|
||||
* Number Generators," ACM Transactions on Mathematical Software, 2021.)
|
||||
* Its state consists of four {@code long} fields {@code x0}, {@code x1}, {@code x2},
|
||||
* and {@code x3}, which can take on any values provided that they are not all zero.
|
||||
* The period of this generator is 2<sup>256</sup>-1.
|
||||
@ -89,25 +91,15 @@ import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
|
||||
name = "Xoshiro256PlusPlus",
|
||||
group = "Xoshiro",
|
||||
i = 256, j = 1, k = 0,
|
||||
equidistribution = 4
|
||||
equidistribution = 3
|
||||
)
|
||||
public final class Xoshiro256PlusPlus implements LeapableGenerator {
|
||||
|
||||
/*
|
||||
* Implementation Overview.
|
||||
*
|
||||
* This is an implementation of the xoroshiro128++ algorithm version 1.0,
|
||||
* This is an implementation of the xoshiro256++ algorithm version 1.0,
|
||||
* written in 2019 by David Blackman and Sebastiano Vigna (vigna@acm.org).
|
||||
* See http://xoshiro.di.unimi.it and these two papers:
|
||||
*
|
||||
* Sebastiano Vigna. 2016. An Experimental Exploration of Marsaglia's
|
||||
* xorshift Generators, Scrambled. ACM Transactions on Mathematical
|
||||
* Software 42, 4, Article 30 (June 2016), 23 pages.
|
||||
* https://doi.org/10.1145/2845077
|
||||
*
|
||||
* David Blackman and Sebastiano Vigna. 2018. Scrambled Linear
|
||||
* Pseudorandom Number Generators. Computing Research Repository (CoRR).
|
||||
* http://arxiv.org/abs/1805.01407
|
||||
*
|
||||
* The jump operation moves the current generator forward by 2*128
|
||||
* steps; this has the same effect as calling nextLong() 2**128
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user