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Mersenne Twister in c# & golang
using System;
public class MT19937
{
private const ulong N = 312;
private const ulong M = 156;
private const ulong MATRIX_A = 0xB5026F5AA96619E9L;
private const ulong UPPER_MASK = 0xFFFFFFFF80000000;
private const ulong LOWER_MASK = 0X7FFFFFFFUL;
private static ulong [] mt = new ulong[N+1];
private static ulong mti = N + 1;
public MT19937(ulong seed)
{
this.Seed(seed);
}
public void Seed(ulong seed)
{
mt[0]= seed;
for (mti=1; mti < N; mti++)
{
mt[mti] = (6364136223846793005L * (mt[mti-1] ^ (mt[mti-1] >> 62)) + mti);
}
}
public ulong Int63()
{
ulong x = 0;
ulong [] mag01 = new ulong[2] {0x0UL, MATRIX_A};
if (mti >= N)
{
ulong kk;
if (mti == N+1)
{
Seed(5489UL);
}
for (kk=0; kk < (N - M); kk++)
{
x = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (x >> 1) ^ mag01[x & 0x1UL];
}
for (;kk<N-1;kk++)
{
x = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk - M] ^ (x >> 1) ^ mag01[x & 0x1UL];
}
x = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
mt[N-1] = mt[M-1] ^ (x >> 1) ^ mag01[x & 0x1UL];
mti = 0;
}
x = mt[mti++];
x ^= (x >> 29) & 0x5555555555555555L;
x ^= (x << 17) & 0x71D67FFFEDA60000L;
x ^= (x << 37) & 0xFFF7EEE000000000L;
x ^= (x >> 43);
return x;
}
public ulong IntN(ulong value) {
return Int63() % value;
}
}
package MersenneTwister
const N = 312
const M = 156
const MATRIX_A = 0xB5026F5AA96619E9
const UPPER_MASK = 0xFFFFFFFF80000000
const LOWER_MASK = 0x7FFFFFFF
type MT19937_64 struct {
array [312]uint64 //state vector
index uint64 // array index
}
func New() *MT19937_64 {
return &MT19937_64{
index: N + 1,
}
}
func (m *MT19937_64) Seed(seed int64) {
m.array[0] = uint64(seed)
for m.index = 1; m.index < N; m.index++ {
m.array[m.index] = (6364136223846793005*(m.array[m.index-1]^(m.array[m.index-1]>>62)) + m.index)
}
}
func (m *MT19937_64) Int63() uint64 {
var i int
var x uint64
mag01 := []uint64{0, MATRIX_A}
if m.index >= N {
if m.index == N+1 {
m.Seed(int64(5489))
}
for i = 0; i < N-M; i++ {
x = (m.array[i] & UPPER_MASK) | (m.array[i+1] & LOWER_MASK)
m.array[i] = m.array[i+(M)] ^ (x >> 1) ^ mag01[int(x&uint64(1))]
}
for ; i < N-1; i++ {
x = (m.array[i] & UPPER_MASK) | (m.array[i+1] & LOWER_MASK)
m.array[i] = m.array[i+(M-N)] ^ (x >> 1) ^ mag01[int(x&uint64(1))]
}
x = (m.array[N-1] & UPPER_MASK) | (m.array[0] & LOWER_MASK)
m.array[N-1] = m.array[M-1] ^ (x >> 1) ^ mag01[int(x&uint64(1))]
m.index = 0
}
x = m.array[m.index]
m.index++
x ^= (x >> 29) & 0x5555555555555555
x ^= (x << 17) & 0x71D67FFFEDA60000
x ^= (x << 37) & 0xFFF7EEE000000000
x ^= (x >> 43)
return x
}
func (m *MT19937_64) IntN(value uint64) uint64 {
return m.Int63() % value
}
@Russtopia

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@Russtopia Russtopia commented Apr 7, 2019

Please note, if seeding MT with less than 2496 bytes' worth of data it's recommended to run the generator for ~10000 iterations as part of initialization to ensure the full internal state is primed:

https://stackoverflow.com/questions/13114823/priming-the-mersenne-twister-prng#13291297

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