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- /*
- I've wrapped Makoto Matsumoto and Takuji Nishimura's code in a namespace
- so it's better encapsulated. Now you can have multiple random number generators
- and they won't stomp all over eachother's state.
- If you want to use this as a substitute for Math.random(), use the random()
- method like so:
- var m = new MersenneTwister();
- var randomNumber = m.random();
- You can also call the other genrand_{foo}() methods on the instance.
- If you want to use a specific seed in order to get a repeatable random
- sequence, pass an integer into the constructor:
- var m = new MersenneTwister(123);
- and that will always produce the same random sequence.
- Sean McCullough (banksean@gmail.com)
- */
- /*
- A C-program for MT19937, with initialization improved 2002/1/26.
- Coded by Takuji Nishimura and Makoto Matsumoto.
- Before using, initialize the state by using init_genrand(seed)
- or init_by_array(init_key, key_length).
- */
- /**
- @license
- mersenne-twister.js - https://gist.github.com/banksean/300494
- Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
- All rights reserved.
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. 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.
- 3. The names of its contributors may not 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.
- */
- /*
- Any feedback is very welcome.
- http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
- email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
- */
- define(function() {
- var MersenneTwister = function(seed) {
- if (seed == undefined) {
- seed = new Date().getTime();
- }
- /* Period parameters */
- this.N = 624;
- this.M = 397;
- this.MATRIX_A = 0x9908b0df; /* constant vector a */
- this.UPPER_MASK = 0x80000000; /* most significant w-r bits */
- this.LOWER_MASK = 0x7fffffff; /* least significant r bits */
- this.mt = new Array(this.N); /* the array for the state vector */
- this.mti=this.N+1; /* mti==N+1 means mt[N] is not initialized */
- this.init_genrand(seed);
- }
- /* initializes mt[N] with a seed */
- MersenneTwister.prototype.init_genrand = function(s) {
- this.mt[0] = s >>> 0;
- for (this.mti=1; this.mti<this.N; this.mti++) {
- var s = this.mt[this.mti-1] ^ (this.mt[this.mti-1] >>> 30);
- this.mt[this.mti] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253)
- + this.mti;
- /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
- /* In the previous versions, MSBs of the seed affect */
- /* only MSBs of the array mt[]. */
- /* 2002/01/09 modified by Makoto Matsumoto */
- this.mt[this.mti] >>>= 0;
- /* for >32 bit machines */
- }
- }
- /* initialize by an array with array-length */
- /* init_key is the array for initializing keys */
- /* key_length is its length */
- /* slight change for C++, 2004/2/26 */
- //MersenneTwister.prototype.init_by_array = function(init_key, key_length) {
- // var i, j, k;
- // this.init_genrand(19650218);
- // i=1; j=0;
- // k = (this.N>key_length ? this.N : key_length);
- // for (; k; k--) {
- // var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30)
- // this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1664525) << 16) + ((s & 0x0000ffff) * 1664525)))
- // + init_key[j] + j; /* non linear */
- // this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
- // i++; j++;
- // if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
- // if (j>=key_length) j=0;
- // }
- // for (k=this.N-1; k; k--) {
- // var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30);
- // this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1566083941) << 16) + (s & 0x0000ffff) * 1566083941))
- // - i; /* non linear */
- // this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
- // i++;
- // if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
- // }
- //
- // this.mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
- //}
- /* generates a random number on [0,0xffffffff]-interval */
- MersenneTwister.prototype.genrand_int32 = function() {
- var y;
- var mag01 = new Array(0x0, this.MATRIX_A);
- /* mag01[x] = x * MATRIX_A for x=0,1 */
- if (this.mti >= this.N) { /* generate N words at one time */
- var kk;
- if (this.mti == this.N+1) /* if init_genrand() has not been called, */
- this.init_genrand(5489); /* a default initial seed is used */
- for (kk=0;kk<this.N-this.M;kk++) {
- y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
- this.mt[kk] = this.mt[kk+this.M] ^ (y >>> 1) ^ mag01[y & 0x1];
- }
- for (;kk<this.N-1;kk++) {
- y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
- this.mt[kk] = this.mt[kk+(this.M-this.N)] ^ (y >>> 1) ^ mag01[y & 0x1];
- }
- y = (this.mt[this.N-1]&this.UPPER_MASK)|(this.mt[0]&this.LOWER_MASK);
- this.mt[this.N-1] = this.mt[this.M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
- this.mti = 0;
- }
- y = this.mt[this.mti++];
- /* Tempering */
- y ^= (y >>> 11);
- y ^= (y << 7) & 0x9d2c5680;
- y ^= (y << 15) & 0xefc60000;
- y ^= (y >>> 18);
- return y >>> 0;
- }
- /* generates a random number on [0,0x7fffffff]-interval */
- //MersenneTwister.prototype.genrand_int31 = function() {
- // return (this.genrand_int32()>>>1);
- //}
- /* generates a random number on [0,1]-real-interval */
- //MersenneTwister.prototype.genrand_real1 = function() {
- // return this.genrand_int32()*(1.0/4294967295.0);
- // /* divided by 2^32-1 */
- //}
- /* generates a random number on [0,1)-real-interval */
- MersenneTwister.prototype.random = function() {
- return this.genrand_int32()*(1.0/4294967296.0);
- /* divided by 2^32 */
- }
- /* generates a random number on (0,1)-real-interval */
- //MersenneTwister.prototype.genrand_real3 = function() {
- // return (this.genrand_int32() + 0.5)*(1.0/4294967296.0);
- // /* divided by 2^32 */
- //}
- /* generates a random number on [0,1) with 53-bit resolution*/
- //MersenneTwister.prototype.genrand_res53 = function() {
- // var a=this.genrand_int32()>>>5, b=this.genrand_int32()>>>6;
- // return(a*67108864.0+b)*(1.0/9007199254740992.0);
- //}
- /* These real versions are due to Isaku Wada, 2002/01/09 added */
- return MersenneTwister;
- });
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