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https://github.com/stevenrobertson/cuburn.git
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58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
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/* Public domain, FWIW
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* gcc -o genprimes -lgmp genprimes.c; ./genprimes > primes.bin
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* see http://www.ast.cam.ac.uk/~stg20/cuda/random/index.html
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*/
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#include <stdio.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <string.h>
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#include <gmp.h>
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/* To verify the primes against the linked URL, compile this instead:
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int main() {
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FILE *fp = fopen("primes.bin", "r");
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char stuff[5];
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while (fread(stuff, 4, 1, fp) == 1) {
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uint64_t i = *((uint32_t*)stuff);
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i = (i>>24) + (1<<8)*((i>>16)&0xff) + (1<<16)*((i>>8)&0xff) + (1<<24)*(i&0xff);
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uint64_t j = i * 4294967296L - 1;
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uint64_t k = (j-1)/2;
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printf("%lu %lu %lu\n", i, j, k);
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}
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}
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*/
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int main(int argc, char* argv[]) {
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fprintf(stderr, "Generating list of multipliers for mod(2^32) MWC RNG\n");
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mpz_t candidate, twotothethirtytwo;
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mpz_init(candidate);
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mpz_init_set_d(twotothethirtytwo, (double) (4294967296L));
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char bytes[5];
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bytes[4] = 0;
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unsigned int i, found=0;
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for (i = 4294967295L; i > 2147483648; i--) {
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mpz_set_ui(candidate, i);
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mpz_mul(candidate, candidate, twotothethirtytwo);
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mpz_sub_ui(candidate, candidate, 1);
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if(mpz_probab_prime_p(candidate, 200)) {
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mpz_sub_ui(candidate, candidate, 1);
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mpz_tdiv_q_ui(candidate, candidate, 2);
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if(mpz_probab_prime_p(candidate, 200)) {
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bytes[0] = (i>>24)&0xff;
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bytes[1] = (i>>16)&0xff;
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bytes[2] = (i>>8)&0xff;
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bytes[3] = i&0xff;
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fwrite(bytes, 4, 1, stdout);
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found++;
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if (!(found&0xff)) fprintf(stderr, ".");
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}
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}
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}
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fprintf(stderr, "\nFound %d multipliers.\n", found);
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mpz_clear(candidate);
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mpz_clear(twotothethirtytwo);
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}
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