64 lines
1.1 KiB
C
64 lines
1.1 KiB
C
/*
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random numbers
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*/
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#include <math.h>
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#include <setjmp.h>
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#include <stdarg.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "scheme.h"
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#include "mt19937ar.h"
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double rand_double()
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{
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union ieee754_double d;
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d.ieee.mantissa0 = genrand_int32();
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d.ieee.mantissa1 = genrand_int32();
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d.ieee.negative = 0;
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d.ieee.exponent = IEEE754_DOUBLE_BIAS + 0; /* 2^0 */
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return d.d - 1.0;
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}
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float rand_float()
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{
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union ieee754_float f;
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f.ieee.mantissa = genrand_int32();
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f.ieee.negative = 0;
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f.ieee.exponent = IEEE754_FLOAT_BIAS + 0; /* 2^0 */
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return f.f - 1.0;
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}
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double randn()
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{
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double s, vre, vim, ure, uim;
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static double next = -42;
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if (next != -42) {
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s = next;
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next = -42;
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return s;
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}
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do {
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ure = rand_double();
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uim = rand_double();
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vre = 2 * ure - 1;
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vim = 2 * uim - 1;
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s = vre * vre + vim * vim;
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} while (s >= 1);
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s = sqrt(-2 * log(s) / s);
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next = s * vre;
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return s * vim;
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}
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void randomize()
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{
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uint64_t tm = i64time();
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init_by_array((uint32_t *)&tm, 2);
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}
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