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Diffstat (limited to 'gmp/tests/mpn/t-sqrmod_bnm1.c')
| -rw-r--r-- | gmp/tests/mpn/t-sqrmod_bnm1.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/gmp/tests/mpn/t-sqrmod_bnm1.c b/gmp/tests/mpn/t-sqrmod_bnm1.c new file mode 100644 index 0000000000..47ccf81083 --- /dev/null +++ b/gmp/tests/mpn/t-sqrmod_bnm1.c @@ -0,0 +1,191 @@ +/* Test for sqrmod_bnm1 function. + + Contributed to the GNU project by Marco Bodrato. + +Copyright 2009 Free Software Foundation, Inc. + +This file is part of the GNU MP Library test suite. + +The GNU MP Library test suite is free software; you can redistribute it +and/or modify it under the terms of the GNU General Public License as +published by the Free Software Foundation; either version 3 of the License, +or (at your option) any later version. + +The GNU MP Library test suite is distributed in the hope that it will be +useful, but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General +Public License for more details. + +You should have received a copy of the GNU General Public License along with +the GNU MP Library test suite. If not, see https://www.gnu.org/licenses/. */ + + +#include <stdlib.h> +#include <stdio.h> + +#include "gmp.h" +#include "gmp-impl.h" +#include "tests.h" + +/* Sizes are up to 2^SIZE_LOG limbs */ +#ifndef SIZE_LOG +#define SIZE_LOG 12 +#endif + +#ifndef COUNT +#define COUNT 3000 +#endif + +#define MAX_N (1L << SIZE_LOG) +#define MIN_N 1 + +/* + Reference function for squaring modulo B^rn-1. + + The result is expected to be ZERO if and only if one of the operand + already is. Otherwise the class [0] Mod(B^rn-1) is represented by + B^rn-1. This should not be a problem if sqrmod_bnm1 is used to + combine results and obtain a natural number when one knows in + advance that the final value is less than (B^rn-1). +*/ + +static void +ref_sqrmod_bnm1 (mp_ptr rp, mp_size_t rn, mp_srcptr ap, mp_size_t an) +{ + mp_limb_t cy; + + ASSERT (0 < an && an <= rn); + + refmpn_mul (rp, ap, an, ap, an); + an *= 2; + if (an > rn) { + cy = mpn_add (rp, rp, rn, rp + rn, an - rn); + /* If cy == 1, then the value of rp is at most B^rn - 2, so there can + * be no overflow when adding in the carry. */ + MPN_INCR_U (rp, rn, cy); + } +} + +/* + Compare the result of the mpn_sqrmod_bnm1 function in the library + with the reference function above. +*/ + +int +main (int argc, char **argv) +{ + mp_ptr ap, refp, pp, scratch; + int count = COUNT; + int test; + gmp_randstate_ptr rands; + TMP_DECL; + TMP_MARK; + + if (argc > 1) + { + char *end; + count = strtol (argv[1], &end, 0); + if (*end || count <= 0) + { + fprintf (stderr, "Invalid test count: %s.\n", argv[1]); + return 1; + } + } + + tests_start (); + rands = RANDS; + + ASSERT_ALWAYS (mpn_sqrmod_bnm1_next_size (MAX_N) == MAX_N); + + ap = TMP_ALLOC_LIMBS (MAX_N); + refp = TMP_ALLOC_LIMBS (MAX_N * 4); + pp = 1+TMP_ALLOC_LIMBS (MAX_N + 2); + scratch + = 1+TMP_ALLOC_LIMBS (mpn_sqrmod_bnm1_itch (MAX_N, MAX_N) + 2); + + for (test = 0; test < count; test++) + { + unsigned size_min; + unsigned size_range; + mp_size_t an,rn,n; + mp_size_t itch; + mp_limb_t p_before, p_after, s_before, s_after; + + for (size_min = 1; (1L << size_min) < MIN_N; size_min++) + ; + + /* We generate an in the MIN_N <= n <= (1 << size_range). */ + size_range = size_min + + gmp_urandomm_ui (rands, SIZE_LOG + 1 - size_min); + + n = MIN_N + + gmp_urandomm_ui (rands, (1L << size_range) + 1 - MIN_N); + n = mpn_sqrmod_bnm1_next_size (n); + + if (n == 1) + an = 1; + else + an = ((n+1) >> 1) + gmp_urandomm_ui (rands, (n+1) >> 1); + + mpn_random2 (ap, an); + + /* Sometime trigger the borderline conditions + A = -1,0,+1 Mod(B^{n/2}+1). + This only makes sense if there is at least a split, i.e. n is even. */ + if ((test & 0x1f) == 1 && (n & 1) == 0) { + mp_size_t x; + MPN_COPY (ap, ap + (n >> 1), an - (n >> 1)); + MPN_ZERO (ap + an - (n >> 1) , n - an); + x = (n == an) ? 0 : gmp_urandomm_ui (rands, n - an); + ap[x] += gmp_urandomm_ui (rands, 3) - 1; + } + rn = MIN(n, 2*an); + mpn_random2 (pp-1, rn + 2); + p_before = pp[-1]; + p_after = pp[rn]; + + itch = mpn_sqrmod_bnm1_itch (n, an); + ASSERT_ALWAYS (itch <= mpn_sqrmod_bnm1_itch (MAX_N, MAX_N)); + mpn_random2 (scratch-1, itch+2); + s_before = scratch[-1]; + s_after = scratch[itch]; + + mpn_sqrmod_bnm1 ( pp, n, ap, an, scratch); + ref_sqrmod_bnm1 (refp, n, ap, an); + if (pp[-1] != p_before || pp[rn] != p_after + || scratch[-1] != s_before || scratch[itch] != s_after + || mpn_cmp (refp, pp, rn) != 0) + { + printf ("ERROR in test %d, an = %d, n = %d\n", + test, (int) an, (int) n); + if (pp[-1] != p_before) + { + printf ("before pp:"); mpn_dump (pp -1, 1); + printf ("keep: "); mpn_dump (&p_before, 1); + } + if (pp[rn] != p_after) + { + printf ("after pp:"); mpn_dump (pp + rn, 1); + printf ("keep: "); mpn_dump (&p_after, 1); + } + if (scratch[-1] != s_before) + { + printf ("before scratch:"); mpn_dump (scratch-1, 1); + printf ("keep: "); mpn_dump (&s_before, 1); + } + if (scratch[itch] != s_after) + { + printf ("after scratch:"); mpn_dump (scratch + itch, 1); + printf ("keep: "); mpn_dump (&s_after, 1); + } + mpn_dump (ap, an); + mpn_dump (pp, rn); + mpn_dump (refp, rn); + + abort(); + } + } + TMP_FREE; + tests_end (); + return 0; +} |