ref: 0113cd12d5ce3faae500772c76018f0ad4dd776a
dir: /lib/math/ancillary/log-overkill-constants.c/
/* cc -o log-overkill-constants log-overkill-constants.c -lmpfr */ #include <stdint.h> #include <stdio.h> #include <time.h> #include <mpfr.h> #define FLT64_TO_UINT64(f) (*((uint64_t *) ((char *) &f))) #define UINT64_TO_FLT64(u) (*((double *) ((char *) &u))) int main(void) { mpfr_t t1; mpfr_t t2; mpfr_t t3; double d = 0; uint64_t u = 0; size_t j = 0; long int k = 0; mpfr_init2(t1, 10000); mpfr_init2(t2, 10000); mpfr_init2(t3, 10000); /* C1 */ for (k = -5; k >= -20; k -= 5) { printf( "const C%ld : (uint64, uint64, uint64, uint64)[32] = [\n", (k / ( -5))); for (j = 0; j < 32; ++j) { mpfr_set_si(t1, 1, MPFR_RNDN); mpfr_set_si(t2, k, MPFR_RNDN); mpfr_exp2(t2, t2, MPFR_RNDN); mpfr_mul_si(t2, t2, j, MPFR_RNDN); mpfr_add(t1, t1, t2, MPFR_RNDN); /* first, log(1 + ...) */ mpfr_log(t2, t1, MPFR_RNDN); d = mpfr_get_d(t2, MPFR_RNDN); u = FLT64_TO_UINT64(d); printf(" (%#018lx, ", u); mpfr_set_d(t3, d, MPFR_RNDN); mpfr_sub(t2, t2, t3, MPFR_RNDN); d = mpfr_get_d(t2, MPFR_RNDN); u = FLT64_TO_UINT64(d); printf("%#018lx, ", u); /* now, 1/(1 + ...) */ mpfr_pow_si(t2, t1, -1, MPFR_RNDN); d = mpfr_get_d(t2, MPFR_RNDN); u = FLT64_TO_UINT64(d); printf(" %#018lx, ", u); mpfr_set_d(t3, d, MPFR_RNDN); mpfr_sub(t2, t2, t3, MPFR_RNDN); d = mpfr_get_d(t2, MPFR_RNDN); u = FLT64_TO_UINT64(d); printf("%#018lx), /* j = %zu */\n", u, j); } printf("]\n\n"); } return 0; }