SFMT19937 (streams-core 1.0.10 API)

java.lang.Object
- stream.generator.SFMT19937

public class SFMT19937
extends Object

An adapation of SFMT (SIMD oriented Fast Mersenne Twister) version 1.3 by Mutsuo Saito (Hiroshima University) and Makoto Matsumoto (Hiroshima University). This adapation supports only the period 2¹⁹⁹³⁷ − 1; the original supports some longer and shorter periods.

The license (a modified BSD License) for the original C code from which this code is adapted:

 Copyright (c) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima
 University. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
 
     * Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above
       copyright notice, this list of conditions and the following
       disclaimer in the documentation and/or other materials provided
       with the distribution.
     * Neither the name of the Hiroshima University nor the names of
       its contributors may be used to endorse or promote products
       derived from this software without specific prior written
       permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Author:: Adrian King (ceroxylon at hotmail.com)

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) int`	`idx` Index counter of the next `int` to return from `next()`.
`static int`	`MEXP` Mersenne Exponent.
`(package private) static int`	`MSK1` A bitmask parameter, used in the recursion to break symmetry of SIMD.
`(package private) static int`	`MSK2` A bitmask parameter, used in the recursion to break symmetry of SIMD.
`(package private) static int`	`MSK3` A bitmask parameter, used in the recursion to break symmetry of SIMD.
`(package private) static int`	`MSK4` A bitmask parameter, used in the recursion to break symmetry of SIMD.
`(package private) static int`	`N` The SFMT generator has an internal state array of 128-bit integers, and `N` is its size.
`static int`	`N32` `N32` is the size of internal state array when regarded as an array of 32-bit integers.
`(package private) static int[]`	`parity` A parity check vector which certifies the period of 2^MEXP.
`(package private) static int`	`PARITY1` Part of a 128-bit period certification vector.
`(package private) static int`	`PARITY2` Part of a 128-bit period certification vector.
`(package private) static int`	`PARITY3` Part of a 128-bit period certification vector.
`(package private) static int`	`PARITY4` Part of a 128-bit period certification vector.
`(package private) static int`	`POS1` The pick up position of the array.
`(package private) int[]`	`sfmt` The internal state array.
`(package private) static int`	`SL1` The parameter of shift left as four 32-bit registers.
`(package private) static int`	`SL2` The parameter of shift left as one 128-bit register.
`(package private) static int`	`SR1` The parameter of shift right as four 32-bit registers.
`(package private) static int`	`SR2` The parameter of shift right as one 128-bit register.
`(package private) static long`	`uniquifier` A number mixed with the time of day to provide a unique seed to each generator of this type allocated.

Constructor Summary

Constructors
Constructor and Description
`SFMT19937()` Constructor that initially uses a seed based on the time of day.
`SFMT19937(long seed)` Constructor that initializes the internal state array by calling `setSeed(long)` with the specified argument.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) void`	`doRecursion(int[] r, int rI, int[] a, int aI, int[] b, int bI, int[] c, int cI, int[] d, int dI)` Applies the recursion formula.
`void`	`fillArray(int[] array)` Fills the given array with pseudorandom 32-bit integers.
`void`	`fillArray(int[] array, int elems)` Fills the given array with the specified number of pseudorandom 32-bit integers.
`(package private) int`	`func1(int x)` Used by `initByArray(int...)`.
`(package private) int`	`func2(int x)` Used by `initByArray(int...)`.
`(package private) void`	`genRandAll()` Fills the internal state array with pseudorandom integers.
`(package private) void`	`genRandArray(int[] array, int size)` Fills a user-specified array with pseudorandom integers.
`void`	`initByArray(int... key)` Initializes the internal state array with an array of 32-bit integers.
`int`	`minArraySize()` Returns the smallest array size allowed as an argument to `fillArray(int[])`.
`int`	`next()` Generates and returns the next 32-bit pseudorandom number.
`(package private) void`	`periodCertification()` Certifies the period of 2^MEXP.
`void`	`setIntSeed(int seed)` Initializes the internal state array with a 32-bit seed.
`void`	`setSeed(long seed)` Initializes the internal state array with a 64-bit seed.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - MEXP
```
public static final int MEXP
```
    Mersenne Exponent. The period of the sequence is a multiple of 2^MEXP − 1. If you adapt this code to support a different exponent, you must change many of the other constants here as well; consult the original C code.
    
    See Also:
    
    Constant Field Values
  - N
```
static final int N
```
    The SFMT generator has an internal state array of 128-bit integers, and N is its size.
    
    See Also:
    
    Constant Field Values
  - N32
```
public static final int N32
```
    N32 is the size of internal state array when regarded as an array of 32-bit integers.
    
    See Also:
    
    Constant Field Values
  - POS1
```
static final int POS1
```
    The pick up position of the array.
    
    See Also:
    
    Constant Field Values
  - SL1
```
static final int SL1
```
    The parameter of shift left as four 32-bit registers.
    
    See Also:
    
    Constant Field Values
  - SL2
```
static final int SL2
```
    The parameter of shift left as one 128-bit register. The 128-bit integer is shifted by SL2 * 8 bits.
    
    See Also:
    
    Constant Field Values
  - SR1
```
static final int SR1
```
    The parameter of shift right as four 32-bit registers.
    
    See Also:
    
    Constant Field Values
  - SR2
```
static final int SR2
```
    The parameter of shift right as one 128-bit register. The 128-bit integer is shifted by SL2 * 8 bits.
    
    See Also:
    
    Constant Field Values
  - MSK1
```
static final int MSK1
```
    A bitmask parameter, used in the recursion to break symmetry of SIMD.
    
    See Also:
    
    Constant Field Values
  - MSK2
```
static final int MSK2
```
    A bitmask parameter, used in the recursion to break symmetry of SIMD.
    
    See Also:
    
    Constant Field Values
  - MSK3
```
static final int MSK3
```
    A bitmask parameter, used in the recursion to break symmetry of SIMD.
    
    See Also:
    
    Constant Field Values
  - MSK4
```
static final int MSK4
```
    A bitmask parameter, used in the recursion to break symmetry of SIMD.
    
    See Also:
    
    Constant Field Values
  - PARITY1
```
static final int PARITY1
```
    Part of a 128-bit period certification vector.
    
    See Also:
    
    Constant Field Values
  - PARITY2
```
static final int PARITY2
```
    Part of a 128-bit period certification vector.
    
    See Also:
    
    Constant Field Values
  - PARITY3
```
static final int PARITY3
```
    Part of a 128-bit period certification vector.
    
    See Also:
    
    Constant Field Values
  - PARITY4
```
static final int PARITY4
```
    Part of a 128-bit period certification vector.
    
    See Also:
    
    Constant Field Values
  - parity
```
static final int[] parity
```
    A parity check vector which certifies the period of 2^MEXP.
  - uniquifier
```
static long uniquifier
```
    A number mixed with the time of day to provide a unique seed to each generator of this type allocated.
  - sfmt
```
final int[] sfmt
```
    The internal state array. Blocks of four consecutive ints are often treated as a single 128-bit integer that is little-endian—that is, its low-order bits are at lower indices in the array, and high-order bits at higher indices.
  - idx
```
int idx
```
    Index counter of the next int to return from next().
- Constructor Detail
  - SFMT19937
```
public SFMT19937()
```
    Constructor that initially uses a seed based on the time of day.
  - SFMT19937
```
public SFMT19937(long seed)
```
    Constructor that initializes the internal state array by calling setSeed(long) with the specified argument.
    
    Parameters:
    
    seed - initial seed for this generator.
- Method Detail
  - doRecursion
```
void doRecursion(int[] r,
                 int rI,
                 int[] a,
                 int aI,
                 int[] b,
                 int bI,
                 int[] c,
                 int cI,
                 int[] d,
                 int dI)
```
    Applies the recursion formula.
    
    Parameters:
    
    r - output array.
    
    rI - index in r.
    
    a - state array.
    
    aI - index in a.
    
    b - state array.
    
    bI - index in b.
    
    c - state array.
    
    cI - index in c.
    
    d - state array.
    
    dI - index in d.
  - genRandAll
```
void genRandAll()
```
    Fills the internal state array with pseudorandom integers.
  - genRandArray
```
void genRandArray(int[] array,
                  int size)
```
    Fills a user-specified array with pseudorandom integers.
    
    Parameters:
    
    array - 128-bit array to be filled with pseudorandom numbers.
    
    size - number of elements of array to fill.
    
    Throws:
    
    IllegalArgumentException - if size is greater than the length of array, or if size is less than N32, or is not a multiple of 4.
  - func1
```
int func1(int x)
```
    Used by initByArray(int...).
    
    Parameters:
    
    x - 32-bit integer.
    
    Returns:
    
    32-bit integer.
  - func2
```
int func2(int x)
```
    Used by initByArray(int...).
    
    Parameters:
    
    x - 32-bit integer.
    
    Returns:
    
    32-bit integer.
  - periodCertification
```
void periodCertification()
```
    Certifies the period of 2^MEXP.
  - minArraySize
```
public int minArraySize()
```
    Returns the smallest array size allowed as an argument to fillArray(int[]).
  - next
```
public int next()
```
    Generates and returns the next 32-bit pseudorandom number.
    
    Returns:
    
    next number.
  - fillArray
```
public void fillArray(int[] array)
```
    Fills the given array with pseudorandom 32-bit integers. Equivalent to fillArray(int[],int) applied to (array,array.length).
    
    Parameters:
    
    array - array to fill.
  - fillArray
```
public void fillArray(int[] array,
                      int elems)
```
    Fills the given array with the specified number of pseudorandom 32-bit integers. The specified number of elements must be a multiple of four.
    
    Parameters:
    
    array - array to fill.
    
    elems - the number of elements of array (starting at index zero) to fill; subsequent elements are not modified.
    
    Throws:
    
    IllegalArgumentException - if elems is greater than the length of array, or is less than N32, or is not a multiple of 4.
  - setIntSeed
```
public void setIntSeed(int seed)
```
    Initializes the internal state array with a 32-bit seed.
    
    Parameters:
    
    seed - 32-bit seed.
  - setSeed
```
public void setSeed(long seed)
```
    Initializes the internal state array with a 64-bit seed.
    
    Parameters:
    
    seed - 64-bit seed.
  - initByArray
```
public void initByArray(int... key)
```
    Initializes the internal state array with an array of 32-bit integers.
    
    Parameters:
    
    key - array of 32-bit integers, used as a seed.

Class SFMT19937

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MEXP

N

N32

POS1

SL1

SL2

SR1

SR2

MSK1

MSK2

MSK3

MSK4

PARITY1

PARITY2

PARITY3

PARITY4

parity

uniquifier

sfmt

idx

Constructor Detail

SFMT19937

SFMT19937

Method Detail

doRecursion

genRandAll

genRandArray

func1

func2

periodCertification

minArraySize

next

fillArray

fillArray

setIntSeed

setSeed

initByArray