Pseudo-random numbers/Combined recursive generator MRG32k3a: Difference between revisions
Pseudo-random numbers/Combined recursive generator MRG32k3a (view source)
Revision as of 00:25, 16 March 2021
, 3 years ago→{{header|Factor}}
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0 : 20002 1 : 20060 2 : 19948 3 : 20059 4 : 19931
</pre>
=={{header|C}}==
<lang c>#include <math.h>
#include <stdio.h>
#include <stdint.h>
int64_t mod(int64_t x, int64_t y) {
int64_t m = x % y;
if (m < 0) {
if (y < 0) {
return m - y;
} else {
return m + y;
}
}
return m;
}
// Constants
// First generator
const static int64_t a1[3] = { 0, 1403580, -810728 };
const static int64_t m1 = (1LL << 32) - 209;
// Second generator
const static int64_t a2[3] = { 527612, 0, -1370589 };
const static int64_t m2 = (1LL << 32) - 22853;
const static int64_t d = (1LL << 32) - 209 + 1; // m1 + 1
// the last three values of the first generator
static int64_t x1[3];
// the last three values of the second generator
static int64_t x2[3];
void seed(int64_t seed_state) {
x1[0] = seed_state;
x1[1] = 0;
x1[2] = 0;
x2[0] = seed_state;
x2[1] = 0;
x2[2] = 0;
}
int64_t next_int() {
int64_t x1i = mod((a1[0] * x1[0] + a1[1] * x1[1] + a1[2] * x1[2]), m1);
int64_t x2i = mod((a2[0] * x2[0] + a2[1] * x2[1] + a2[2] * x2[2]), m2);
int64_t z = mod(x1i - x2i, m1);
// keep last three values of the first generator
x1[2] = x1[1];
x1[1] = x1[0];
x1[0] = x1i;
// keep last three values of the second generator
x2[2] = x2[1];
x2[1] = x2[0];
x2[0] = x2i;
return z + 1;
}
double next_float() {
return (double)next_int() / d;
}
int main() {
int counts[5] = { 0, 0, 0, 0, 0 };
int i;
seed(1234567);
printf("%lld\n", next_int());
printf("%lld\n", next_int());
printf("%lld\n", next_int());
printf("%lld\n", next_int());
printf("%lld\n", next_int());
printf("\n");
seed(987654321);
for (i = 0; i < 100000; i++) {
int64_t value = floor(next_float() * 5);
counts[value]++;
}
for (i = 0; i < 5; i++) {
printf("%d: %d\n", i, counts[i]);
}
return 0;
}</lang>
{{out}}
<pre>1459213977
2827710106
4245671317
3877608661
2595287583
0: 20002
1: 20060
2: 19948
3: 20059
4: 19931</pre>
=={{header|Factor}}==
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