1 /* Exercise mpz_probab_prime_p. 2 3 Copyright 2002 Free Software Foundation, Inc. 4 5 This file is part of the GNU MP Library test suite. 6 7 The GNU MP Library test suite is free software; you can redistribute it 8 and/or modify it under the terms of the GNU General Public License as 9 published by the Free Software Foundation; either version 3 of the License, 10 or (at your option) any later version. 11 12 The GNU MP Library test suite is distributed in the hope that it will be 13 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 15 Public License for more details. 16 17 You should have received a copy of the GNU General Public License along with 18 the GNU MP Library test suite. If not, see http://www.gnu.org/licenses/. */ 19 20 #include <stdio.h> 21 #include <stdlib.h> 22 #include "gmp.h" 23 #include "gmp-impl.h" 24 #include "tests.h" 25 26 27 /* Enhancements: 28 29 - Test some big primes don't come back claimed to be composite. 30 - Test some big composites don't come back claimed to be certainly prime. 31 - Test some big composites with small factors are identified as certainly 32 composite. */ 33 34 35 /* return 1 if prime, 0 if composite */ 36 int 37 isprime (long n) 38 { 39 long i; 40 41 n = ABS(n); 42 43 if (n < 2) 44 return 0; 45 if (n == 2) 46 return 1; 47 if ((n & 1) == 0) 48 return 0; 49 50 for (i = 3; i < n; i++) 51 if ((n % i) == 0) 52 return 0; 53 54 return 1; 55 } 56 57 void 58 check_one (mpz_srcptr n, int want) 59 { 60 int got; 61 62 got = mpz_probab_prime_p (n, 25); 63 64 /* "definitely prime" is fine if we only wanted "probably prime" */ 65 if (got == 2 && want == 1) 66 want = 2; 67 68 if (got != want) 69 { 70 printf ("mpz_probab_prime_p\n"); 71 mpz_trace (" n ", n); 72 printf (" got =%d", got); 73 printf (" want=%d", want); 74 abort (); 75 } 76 } 77 78 void 79 check_pn (mpz_ptr n, int want) 80 { 81 check_one (n, want); 82 mpz_neg (n, n); 83 check_one (n, want); 84 } 85 86 /* expect certainty for small n */ 87 void 88 check_small (void) 89 { 90 mpz_t n; 91 long i; 92 93 mpz_init (n); 94 95 for (i = 0; i < 300; i++) 96 { 97 mpz_set_si (n, i); 98 check_pn (n, isprime (i)); 99 } 100 101 mpz_clear (n); 102 } 103 104 int 105 main (void) 106 { 107 tests_start (); 108 109 check_small (); 110 111 tests_end (); 112 exit (0); 113 } 114