1 /* Test for sqrmod_bnm1 function. 2 3 Contributed to the GNU project by Marco Bodrato. 4 5 Copyright 2009 Free Software Foundation, Inc. 6 7 This file is part of the GNU MP Library test suite. 8 9 The GNU MP Library test suite is free software; you can redistribute it 10 and/or modify it under the terms of the GNU General Public License as 11 published by the Free Software Foundation; either version 3 of the License, 12 or (at your option) any later version. 13 14 The GNU MP Library test suite is distributed in the hope that it will be 15 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 17 Public License for more details. 18 19 You should have received a copy of the GNU General Public License along with 20 the GNU MP Library test suite. If not, see http://www.gnu.org/licenses/. */ 21 22 23 #include <stdlib.h> 24 #include <stdio.h> 25 26 #include "gmp.h" 27 #include "gmp-impl.h" 28 #include "tests.h" 29 30 /* Sizes are up to 2^SIZE_LOG limbs */ 31 #ifndef SIZE_LOG 32 #define SIZE_LOG 12 33 #endif 34 35 #ifndef COUNT 36 #define COUNT 3000 37 #endif 38 39 #define MAX_N (1L << SIZE_LOG) 40 #define MIN_N 1 41 42 /* 43 Reference function for squaring modulo B^rn-1. 44 45 The result is expected to be ZERO if and only if one of the operand 46 already is. Otherwise the class [0] Mod(B^rn-1) is represented by 47 B^rn-1. This should not be a problem if sqrmod_bnm1 is used to 48 combine results and obtain a natural number when one knows in 49 advance that the final value is less than (B^rn-1). 50 */ 51 52 static void 53 ref_sqrmod_bnm1 (mp_ptr rp, mp_size_t rn, mp_srcptr ap, mp_size_t an) 54 { 55 mp_limb_t cy; 56 57 ASSERT (0 < an && an <= rn); 58 59 refmpn_mul (rp, ap, an, ap, an); 60 an *= 2; 61 if (an > rn) { 62 cy = mpn_add (rp, rp, rn, rp + rn, an - rn); 63 /* If cy == 1, then the value of rp is at most B^rn - 2, so there can 64 * be no overflow when adding in the carry. */ 65 MPN_INCR_U (rp, rn, cy); 66 } 67 } 68 69 /* 70 Compare the result of the mpn_sqrmod_bnm1 function in the library 71 with the reference function above. 72 */ 73 74 int 75 main (int argc, char **argv) 76 { 77 mp_ptr ap, refp, pp, scratch; 78 int count = COUNT; 79 int test; 80 gmp_randstate_ptr rands; 81 TMP_DECL; 82 TMP_MARK; 83 84 if (argc > 1) 85 { 86 char *end; 87 count = strtol (argv[1], &end, 0); 88 if (*end || count <= 0) 89 { 90 fprintf (stderr, "Invalid test count: %s.\n", argv[1]); 91 return 1; 92 } 93 } 94 95 tests_start (); 96 rands = RANDS; 97 98 ASSERT_ALWAYS (mpn_sqrmod_bnm1_next_size (MAX_N) == MAX_N); 99 100 ap = TMP_ALLOC_LIMBS (MAX_N); 101 refp = TMP_ALLOC_LIMBS (MAX_N * 4); 102 pp = 1+TMP_ALLOC_LIMBS (MAX_N + 2); 103 scratch 104 = 1+TMP_ALLOC_LIMBS (mpn_sqrmod_bnm1_itch (MAX_N, MAX_N) + 2); 105 106 for (test = 0; test < count; test++) 107 { 108 unsigned size_min; 109 unsigned size_range; 110 mp_size_t an,rn,n; 111 mp_size_t itch; 112 mp_limb_t p_before, p_after, s_before, s_after; 113 114 for (size_min = 1; (1L << size_min) < MIN_N; size_min++) 115 ; 116 117 /* We generate an in the MIN_N <= n <= (1 << size_range). */ 118 size_range = size_min 119 + gmp_urandomm_ui (rands, SIZE_LOG + 1 - size_min); 120 121 n = MIN_N 122 + gmp_urandomm_ui (rands, (1L << size_range) + 1 - MIN_N); 123 n = mpn_sqrmod_bnm1_next_size (n); 124 125 if (n == 1) 126 an = 1; 127 else 128 an = ((n+1) >> 1) + gmp_urandomm_ui (rands, (n+1) >> 1); 129 130 mpn_random2 (ap, an); 131 132 /* Sometime trigger the borderline conditions 133 A = -1,0,+1 Mod(B^{n/2}+1). 134 This only makes sense if there is at least a split, i.e. n is even. */ 135 if ((test & 0x1f) == 1 && (n & 1) == 0) { 136 mp_size_t x; 137 MPN_COPY (ap, ap + (n >> 1), an - (n >> 1)); 138 MPN_ZERO (ap + an - (n >> 1) , n - an); 139 x = (n == an) ? 0 : gmp_urandomm_ui (rands, n - an); 140 ap[x] += gmp_urandomm_ui (rands, 3) - 1; 141 } 142 rn = MIN(n, 2*an); 143 mpn_random2 (pp-1, rn + 2); 144 p_before = pp[-1]; 145 p_after = pp[rn]; 146 147 itch = mpn_sqrmod_bnm1_itch (n, an); 148 ASSERT_ALWAYS (itch <= mpn_sqrmod_bnm1_itch (MAX_N, MAX_N)); 149 mpn_random2 (scratch-1, itch+2); 150 s_before = scratch[-1]; 151 s_after = scratch[itch]; 152 153 mpn_sqrmod_bnm1 ( pp, n, ap, an, scratch); 154 ref_sqrmod_bnm1 (refp, n, ap, an); 155 if (pp[-1] != p_before || pp[rn] != p_after 156 || scratch[-1] != s_before || scratch[itch] != s_after 157 || mpn_cmp (refp, pp, rn) != 0) 158 { 159 printf ("ERROR in test %d, an = %d, n = %d\n", 160 test, (int) an, (int) n); 161 if (pp[-1] != p_before) 162 { 163 printf ("before pp:"); mpn_dump (pp -1, 1); 164 printf ("keep: "); mpn_dump (&p_before, 1); 165 } 166 if (pp[rn] != p_after) 167 { 168 printf ("after pp:"); mpn_dump (pp + rn, 1); 169 printf ("keep: "); mpn_dump (&p_after, 1); 170 } 171 if (scratch[-1] != s_before) 172 { 173 printf ("before scratch:"); mpn_dump (scratch-1, 1); 174 printf ("keep: "); mpn_dump (&s_before, 1); 175 } 176 if (scratch[itch] != s_after) 177 { 178 printf ("after scratch:"); mpn_dump (scratch + itch, 1); 179 printf ("keep: "); mpn_dump (&s_after, 1); 180 } 181 mpn_dump (ap, an); 182 mpn_dump (pp, rn); 183 mpn_dump (refp, rn); 184 185 abort(); 186 } 187 } 188 TMP_FREE; 189 tests_end (); 190 return 0; 191 } 192