70 lines
1.7 KiB
JavaScript
70 lines
1.7 KiB
JavaScript
// Code adapted to JS module. Original mersenne.js (c) 2014 Stephan Brumme.
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export class MersenneTwister {
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constructor( seed ) {
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this.state = new Array(624);
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this.next = null;
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if ( seed === undefined ) {
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seed = 5489;
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}
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this.seed = seed;
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this.state[ 0 ] = this.seed;
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let s = null;
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for ( let i = 1 ; i < 624; i++ ) {
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s = this.state[ i - 1 ] ^ ( this.state[ i - 1 ] >>> 30);
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this.state[ i ] = ( ( ( ( ( s & 0xffff0000 ) >>> 16 ) * 1812433253 ) << 16 ) +
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( s & 0x0000ffff ) * 1812433253 ) + i;
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this.state[ i ] |= 0;
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}
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this.twist();
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}
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twist() {
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let i = 0;
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let bits = 0;
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for ( i = 0; i < 227; i++ )
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{
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bits = ( this.state[ i ] & 0x80000000) | ( this.state[ i + 1 ] & 0x7fffffff);
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this.state[ i ] = this.state[ i + 397 ] ^ ( bits >>> 1 ) ^ ( ( bits & 1 ) * 0x9908b0df );
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}
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for ( i = 227 ; i < 623; i++ )
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{
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bits = ( this.state[ i ] & 0x80000000) | ( this.state[ i + 1 ] & 0x7fffffff );
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this.state[ i ] = this.state[ i - 227 ] ^ ( bits >>> 1 ) ^ ( ( bits & 1 ) * 0x9908b0df );
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}
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bits = ( this.state[ 623 ] & 0x80000000 ) | ( this.state[ 0 ] & 0x7fffffff );
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this.state[ 623 ] = this.state[ 396 ] ^ ( bits >>> 1 ) ^ ( ( bits & 1 ) * 0x9908b0df );
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this.next = 0;
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}
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random = function() {
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if ( this.next >= 624 ) {
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this.twist();
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}
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let x = this.state[ this.next++ ];
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x ^= x >>> 11;
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x ^= (x << 7) & 0x9d2c5680;
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x ^= (x << 15) & 0xefc60000;
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x ^= x >>> 18;
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return x;
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}
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randomRange( min, max ) {
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let x = Math.abs( this.random() );
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let l = Math.pow( 10, x.toString().length );
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let y = Math.round( ( Math.floor( ( x / l ) * ( Math.floor( max * 100 ) - Math.ceil( min * 10 ) ) ) + Math.ceil( min * 10 ) ) / 100 );
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return y;
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}
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} |