math.rng

Class BitMix

java.lang.Object

math.rng.BitMix

public final class BitMix
extends Object

A selection of 64-bit mixing functions for longs and 32-bit mixing functions for ints.

Method Summary

Modifier and Type	Method and Description
static long	applebyMix64(long v) Austin Appleby's fmix64() mix function used in MurmurHash3.
static int	leaMix32(int v) Doug Lea's 32-bit mixing function.
static long	leaMix64(long v) Doug Lea's 64-bit mixing function.
static long	pelican(long v) Tommy Ettinger's Pelican mixer.
static long	rrmxmx(long v) Pelle Evensen's better mixer (see "http://mostlymangling.blogspot.com/2018/07/on-mixing-functions-in-fast-splittable.html").
static long	rrxmrrxmsx(long v) Pelle Evensen's even better mixer (a bit slower than rrmxmx(long).
static int	staffordMix04(long v) David Stafford's variant 4 of his 64-bit mixing functions adapted to return the 32 high bits as an int.
static long	staffordMix13(long v) David Stafford's variant 13 of his 64-bit mixing functions.
static long	xnasam(long v) A variant of xnasam(long, long) where 0x6a09e667f3bcc909L (chosen at random) is used as a fixed value for the constant c.
static long	xnasam(long v, long c) Pelle Evensen's xNASAM ("Not Another Strange Acronym Mixer") mixer (slower than the rr... mixers).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

rrmxmx

public static long rrmxmx(long v)

Pelle Evensen's better mixer (see "http://mostlymangling.blogspot.com/2018/07/on-mixing-functions-in-fast-splittable.html").

Parameters:

v - long to mix

Returns:

the mixed long

rrxmrrxmsx

public static long rrxmrrxmsx(long v)

Pelle Evensen's even better mixer (a bit slower than rrmxmx(long). See "https://mostlymangling.blogspot.com/2019/01/better-stronger-mixer-and-test-procedure.html".

Parameters:

v - long to mix

Returns:

the mixed long

xnasam

public static long xnasam(long v,
                          long c)

Pelle Evensen's xNASAM ("Not Another Strange Acronym Mixer") mixer (slower than the rr... mixers). See "http://mostlymangling.blogspot.com/2020/01/nasam-not-another-strange-acronym-mixer.html".

Parameters:

v - long to mix

c - a constant with which v becomes xor-ed before the mixing steps

Returns:

the mixed long

xnasam

public static long xnasam(long v)

A variant of xnasam(long, long) where 0x6a09e667f3bcc909L (chosen at random) is used as a fixed value for the constant c.

Parameters:

v - long to mix

Returns:

the mixed long

pelican

public static long pelican(long v)

Tommy Ettinger's Pelican mixer. See "https://github.com/tommyettinger/sarong/blob/master/src/main/java/sarong/PelicanRNG.java".

Parameters:

v - long to mix

Returns:

the mixed long

staffordMix13

public static long staffordMix13(long v)

David Stafford's variant 13 of his 64-bit mixing functions. See "http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html". Note that if the argument v is 0, the result is 0.

Parameters:

v - long to mix

Returns:

the mixed long

leaMix64

public static long leaMix64(long v)

Doug Lea's 64-bit mixing function. Note that if the argument v is 0, the result is 0.

Parameters:

v - long to mix

Returns:

the mixed long

applebyMix64

public static long applebyMix64(long v)

Austin Appleby's fmix64() mix function used in MurmurHash3. See "https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp". Note that if the argument v is 0, the result is 0.

Parameters:

v - long to mix

Returns:

the mixed long

staffordMix04

public static int staffordMix04(long v)

David Stafford's variant 4 of his 64-bit mixing functions adapted to return the 32 high bits as an int. See "http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html". Note that if the argument v is 0, the result is 0.

Parameters:

v - long to mix

Returns:

a mixed int

leaMix32

public static int leaMix32(int v)

Doug Lea's 32-bit mixing function. Note that if the argument v is 0, the result is 0.

Parameters:

v - int to mix

Returns:

the mixed int