108 lines
3.4 KiB
JavaScript
108 lines
3.4 KiB
JavaScript
var MersenneTwister = function(seed) {
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if (seed == undefined) {
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seed = new Date().getTime();
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}
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this.N = 624;
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this.M = 397;
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this.MATRIX_A = 0x9908b0df;
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this.UPPER_MASK = 0x80000000;
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this.LOWER_MASK = 0x7fffffff;
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this.mt = new Array(this.N);
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this.mti = this.N + 1;
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this.init_genrand(seed);
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}
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MersenneTwister.prototype.init_genrand = function(s) {
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this.mt[0] = s >>> 0;
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for (this.mti = 1; this.mti < this.N; this.mti++) {
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var s = this.mt[this.mti - 1] ^ (this.mt[this.mti - 1] >>> 30);
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this.mt[this.mti] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253) +
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this.mti;
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this.mt[this.mti] >>>= 0;
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}
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}
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MersenneTwister.prototype.init_by_array = function(init_key, key_length) {
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var i, j, k;
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this.init_genrand(19650218);
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i = 1;
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j = 0;
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k = (this.N > key_length ? this.N : key_length);
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for (; k; k--) {
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var s = this.mt[i - 1] ^ (this.mt[i - 1] >>> 30)
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this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1664525) << 16) + ((s & 0x0000ffff) * 1664525))) +
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init_key[j] + j;
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this.mt[i] >>>= 0;
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i++;
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j++;
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if (i >= this.N) {
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this.mt[0] = this.mt[this.N - 1];
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i = 1;
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}
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if (j >= key_length) j = 0;
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}
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for (k = this.N - 1; k; k--) {
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var s = this.mt[i - 1] ^ (this.mt[i - 1] >>> 30);
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this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1566083941) << 16) + (s & 0x0000ffff) * 1566083941)) -
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i;
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this.mt[i] >>>= 0;
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i++;
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if (i >= this.N) {
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this.mt[0] = this.mt[this.N - 1];
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i = 1;
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}
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}
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this.mt[0] = 0x80000000;
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}
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MersenneTwister.prototype.genrand_int32 = function() {
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var y;
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var mag01 = new Array(0x0, this.MATRIX_A);
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if (this.mti >= this.N) {
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var kk;
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if (this.mti == this.N + 1)
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this.init_genrand(5489);
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for (kk = 0; kk < this.N - this.M; kk++) {
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y = (this.mt[kk] & this.UPPER_MASK) | (this.mt[kk + 1] & this.LOWER_MASK);
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this.mt[kk] = this.mt[kk + this.M] ^ (y >>> 1) ^ mag01[y & 0x1];
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}
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for (; kk < this.N - 1; kk++) {
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y = (this.mt[kk] & this.UPPER_MASK) | (this.mt[kk + 1] & this.LOWER_MASK);
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this.mt[kk] = this.mt[kk + (this.M - this.N)] ^ (y >>> 1) ^ mag01[y & 0x1];
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}
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y = (this.mt[this.N - 1] & this.UPPER_MASK) | (this.mt[0] & this.LOWER_MASK);
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this.mt[this.N - 1] = this.mt[this.M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
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this.mti = 0;
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}
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y = this.mt[this.mti++];
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y ^= (y >>> 11);
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y ^= (y << 7) & 0x9d2c5680;
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y ^= (y << 15) & 0xefc60000;
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y ^= (y >>> 18);
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return y >>> 0;
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}
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MersenneTwister.prototype.genrand_int31 = function() {
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return (this.genrand_int32() >>> 1);
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}
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MersenneTwister.prototype.genrand_real1 = function() {
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return this.genrand_int32() * (1.0 / 4294967295.0);
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}
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MersenneTwister.prototype.random = function() {
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return this.genrand_int32() * (1.0 / 4294967296.0);
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}
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MersenneTwister.prototype.genrand_real3 = function() {
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return (this.genrand_int32() + 0.5) * (1.0 / 4294967296.0);
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}
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MersenneTwister.prototype.genrand_res53 = function() {
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var a = this.genrand_int32() >>> 5,
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b = this.genrand_int32() >>> 6;
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return (a * 67108864.0 + b) * (1.0 / 9007199254740992.0);
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}
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module.exports = MersenneTwister;
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