t-jac.c
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上传日期:2022-08-06
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- /* Exercise mpz_*_kronecker_*() and mpz_jacobi() functions.
- Copyright 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP Library is free software; you can redistribute it and/or modify
- it under the terms of the GNU Lesser 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 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 Lesser General Public
- License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
- /* With no arguments the various Kronecker/Jacobi symbol routines are
- checked against some test data and a lot of derived data.
- To check the test data against PARI-GP, run
- t-jac -p | gp -q
- It takes a while because the output from "t-jac -p" is big.
- Enhancements:
- More big test cases than those given by check_squares_zi would be good. */
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include "gmp.h"
- #include "gmp-impl.h"
- #include "tests.h"
- #ifdef _LONG_LONG_LIMB
- #define LL(l,ll) ll
- #else
- #define LL(l,ll) l
- #endif
- int option_pari = 0;
- unsigned long
- mpz_mod4 (mpz_srcptr z)
- {
- mpz_t m;
- unsigned long ret;
- mpz_init (m);
- mpz_fdiv_r_2exp (m, z, 2);
- ret = mpz_get_ui (m);
- mpz_clear (m);
- return ret;
- }
- int
- mpz_fits_ulimb_p (mpz_srcptr z)
- {
- return (SIZ(z) == 1 || SIZ(z) == 0);
- }
- mp_limb_t
- mpz_get_ulimb (mpz_srcptr z)
- {
- if (SIZ(z) == 0)
- return 0;
- else
- return PTR(z)[0];
- }
- void
- try_base (mp_limb_t a, mp_limb_t b, int answer)
- {
- int got;
- if ((b & 1) == 0 || b == 1 || a > b)
- return;
- got = mpn_jacobi_base (a, b, 0);
- if (got != answer)
- {
- printf (LL("mpn_jacobi_base (%lu, %lu) is %d should be %dn",
- "mpn_jacobi_base (%llu, %llu) is %d should be %dn"),
- a, b, got, answer);
- abort ();
- }
- }
- void
- try_zi_ui (mpz_srcptr a, unsigned long b, int answer)
- {
- int got;
- got = mpz_kronecker_ui (a, b);
- if (got != answer)
- {
- printf ("mpz_kronecker_ui (");
- mpz_out_str (stdout, 10, a);
- printf (", %lu) is %d should be %dn", b, got, answer);
- abort ();
- }
- }
- void
- try_zi_si (mpz_srcptr a, long b, int answer)
- {
- int got;
- got = mpz_kronecker_si (a, b);
- if (got != answer)
- {
- printf ("mpz_kronecker_si (");
- mpz_out_str (stdout, 10, a);
- printf (", %ld) is %d should be %dn", b, got, answer);
- abort ();
- }
- }
- void
- try_ui_zi (unsigned long a, mpz_srcptr b, int answer)
- {
- int got;
- got = mpz_ui_kronecker (a, b);
- if (got != answer)
- {
- printf ("mpz_ui_kronecker (%lu, ", a);
- mpz_out_str (stdout, 10, b);
- printf (") is %d should be %dn", got, answer);
- abort ();
- }
- }
- void
- try_si_zi (long a, mpz_srcptr b, int answer)
- {
- int got;
- got = mpz_si_kronecker (a, b);
- if (got != answer)
- {
- printf ("mpz_si_kronecker (%ld, ", a);
- mpz_out_str (stdout, 10, b);
- printf (") is %d should be %dn", got, answer);
- abort ();
- }
- }
- /* Don't bother checking mpz_jacobi, since it only differs for b even, and
- we don't have an actual expected answer for it. tests/devel/try.c does
- some checks though. */
- void
- try_zi_zi (mpz_srcptr a, mpz_srcptr b, int answer)
- {
- int got;
- got = mpz_kronecker (a, b);
- if (got != answer)
- {
- printf ("mpz_kronecker (");
- mpz_out_str (stdout, 10, a);
- printf (", ");
- mpz_out_str (stdout, 10, b);
- printf (") is %d should be %dn", got, answer);
- abort ();
- }
- }
- void
- try_pari (mpz_srcptr a, mpz_srcptr b, int answer)
- {
- printf ("try(");
- mpz_out_str (stdout, 10, a);
- printf (",");
- mpz_out_str (stdout, 10, b);
- printf (",%d)n", answer);
- }
- void
- try_each (mpz_srcptr a, mpz_srcptr b, int answer)
- {
- if (option_pari)
- {
- try_pari (a, b, answer);
- return;
- }
- if (mpz_fits_ulimb_p (a) && mpz_fits_ulimb_p (b))
- try_base (mpz_get_ulimb (a), mpz_get_ulimb (b), answer);
- if (mpz_fits_ulong_p (b))
- try_zi_ui (a, mpz_get_ui (b), answer);
- if (mpz_fits_slong_p (b))
- try_zi_si (a, mpz_get_si (b), answer);
- if (mpz_fits_ulong_p (a))
- try_ui_zi (mpz_get_ui (a), b, answer);
- if (mpz_fits_sint_p (a))
- try_si_zi (mpz_get_si (a), b, answer);
- try_zi_zi (a, b, answer);
- }
- /* Try (a/b) and (a/-b). */
- void
- try_pn (mpz_srcptr a, mpz_srcptr b_orig, int answer)
- {
- mpz_t b;
- mpz_init_set (b, b_orig);
- try_each (a, b, answer);
- mpz_neg (b, b);
- if (mpz_sgn (a) < 0)
- answer = -answer;
- try_each (a, b, answer);
- mpz_clear (b);
- }
- /* Try (a+k*p/b) for various k, using the fact (a/b) is periodic in a with
- period p. For b>0, p=b if b!=2mod4 or p=4*b if b==2mod4. */
- void
- try_periodic_num (mpz_srcptr a_orig, mpz_srcptr b, int answer)
- {
- mpz_t a, a_period;
- int i;
- if (mpz_sgn (b) <= 0)
- return;
- mpz_init_set (a, a_orig);
- mpz_init_set (a_period, b);
- if (mpz_mod4 (b) == 2)
- mpz_mul_ui (a_period, a_period, 4);
- /* don't bother with these tests if they're only going to produce
- even/even */
- if (mpz_even_p (a) && mpz_even_p (b) && mpz_even_p (a_period))
- goto done;
- for (i = 0; i < 6; i++)
- {
- mpz_add (a, a, a_period);
- try_pn (a, b, answer);
- }
- mpz_set (a, a_orig);
- for (i = 0; i < 6; i++)
- {
- mpz_sub (a, a, a_period);
- try_pn (a, b, answer);
- }
- done:
- mpz_clear (a);
- mpz_clear (a_period);
- }
- /* Try (a/b+k*p) for various k, using the fact (a/b) is periodic in b of
- period p.
- period p
- a==0,1mod4 a
- a==2mod4 4*a
- a==3mod4 and b odd 4*a
- a==3mod4 and b even 8*a
- In Henri Cohen's book the period is given as 4*a for all a==2,3mod4, but
- a counterexample would seem to be (3/2)=-1 which with (3/14)=+1 doesn't
- have period 4*a (but rather 8*a with (3/26)=-1). Maybe the plain 4*a is
- to be read as applying to a plain Jacobi symbol with b odd, rather than
- the Kronecker extension to b even. */
- void
- try_periodic_den (mpz_srcptr a, mpz_srcptr b_orig, int answer)
- {
- mpz_t b, b_period;
- int i;
- if (mpz_sgn (a) == 0 || mpz_sgn (b_orig) == 0)
- return;
- mpz_init_set (b, b_orig);
- mpz_init_set (b_period, a);
- if (mpz_mod4 (a) == 3 && mpz_even_p (b))
- mpz_mul_ui (b_period, b_period, 8L);
- else if (mpz_mod4 (a) >= 2)
- mpz_mul_ui (b_period, b_period, 4L);
- /* don't bother with these tests if they're only going to produce
- even/even */
- if (mpz_even_p (a) && mpz_even_p (b) && mpz_even_p (b_period))
- goto done;
- for (i = 0; i < 6; i++)
- {
- mpz_add (b, b, b_period);
- try_pn (a, b, answer);
- }
- mpz_set (b, b_orig);
- for (i = 0; i < 6; i++)
- {
- mpz_sub (b, b, b_period);
- try_pn (a, b, answer);
- }
- done:
- mpz_clear (b);
- mpz_clear (b_period);
- }
- static const unsigned long ktable[] = {
- 0, 1, 2, 3, 4, 5, 6, 7,
- GMP_NUMB_BITS-1, GMP_NUMB_BITS, GMP_NUMB_BITS+1,
- 2*GMP_NUMB_BITS-1, 2*GMP_NUMB_BITS, 2*GMP_NUMB_BITS+1,
- 3*GMP_NUMB_BITS-1, 3*GMP_NUMB_BITS, 3*GMP_NUMB_BITS+1
- };
- /* Try (a/b*2^k) for various k. */
- void
- try_2den (mpz_srcptr a, mpz_srcptr b_orig, int answer)
- {
- mpz_t b;
- int kindex;
- int answer_a2, answer_k;
- unsigned long k;
- /* don't bother when b==0 */
- if (mpz_sgn (b_orig) == 0)
- return;
- mpz_init_set (b, b_orig);
- /* (a/2) is 0 if a even, 1 if a==1 or 7 mod 8, -1 if a==3 or 5 mod 8 */
- answer_a2 = (mpz_even_p (a) ? 0
- : (((SIZ(a) >= 0 ? PTR(a)[0] : -PTR(a)[0]) + 2) & 7) < 4 ? 1
- : -1);
- for (kindex = 0; kindex < numberof (ktable); kindex++)
- {
- k = ktable[kindex];
- /* answer_k = answer*(answer_a2^k) */
- answer_k = (answer_a2 == 0 && k != 0 ? 0
- : (k & 1) == 1 && answer_a2 == -1 ? -answer
- : answer);
- mpz_mul_2exp (b, b_orig, k);
- try_pn (a, b, answer_k);
- }
- mpz_clear (b);
- }
- /* Try (a*2^k/b) for various k. If it happens mpz_ui_kronecker() gets (2/b)
- wrong it will show up as wrong answers demanded. */
- void
- try_2num (mpz_srcptr a_orig, mpz_srcptr b, int answer)
- {
- mpz_t a;
- int kindex;
- int answer_2b, answer_k;
- unsigned long k;
- /* don't bother when a==0 */
- if (mpz_sgn (a_orig) == 0)
- return;
- mpz_init (a);
- /* (2/b) is 0 if b even, 1 if b==1 or 7 mod 8, -1 if b==3 or 5 mod 8 */
- answer_2b = (mpz_even_p (b) ? 0
- : (((SIZ(b) >= 0 ? PTR(b)[0] : -PTR(b)[0]) + 2) & 7) < 4 ? 1
- : -1);
- for (kindex = 0; kindex < numberof (ktable); kindex++)
- {
- k = ktable[kindex];
- /* answer_k = answer*(answer_2b^k) */
- answer_k = (answer_2b == 0 && k != 0 ? 0
- : (k & 1) == 1 && answer_2b == -1 ? -answer
- : answer);
- mpz_mul_2exp (a, a_orig, k);
- try_pn (a, b, answer_k);
- }
- mpz_clear (a);
- }
- /* The try_2num() and try_2den() routines don't in turn call
- try_periodic_num() and try_periodic_den() because it hugely increases the
- number of tests performed, without obviously increasing coverage.
- Useful extra derived cases can be added here. */
- void
- try_all (mpz_t a, mpz_t b, int answer)
- {
- try_pn (a, b, answer);
- try_periodic_num (a, b, answer);
- try_periodic_den (a, b, answer);
- try_2num (a, b, answer);
- try_2den (a, b, answer);
- }
- void
- check_data (void)
- {
- static const struct {
- const char *a;
- const char *b;
- int answer;
- } data[] = {
- /* Note that the various derived checks in try_all() reduce the cases
- that need to be given here. */
- /* some zeros */
- { "0", "0", 0 },
- { "0", "2", 0 },
- { "0", "6", 0 },
- { "5", "0", 0 },
- { "24", "60", 0 },
- /* (a/1) = 1, any a
- In particular note (0/1)=1 so that (a/b)=(a mod b/b). */
- { "0", "1", 1 },
- { "1", "1", 1 },
- { "2", "1", 1 },
- { "3", "1", 1 },
- { "4", "1", 1 },
- { "5", "1", 1 },
- /* (0/b) = 0, b != 1 */
- { "0", "3", 0 },
- { "0", "5", 0 },
- { "0", "7", 0 },
- { "0", "9", 0 },
- { "0", "11", 0 },
- { "0", "13", 0 },
- { "0", "15", 0 },
- /* (1/b) = 1 */
- { "1", "1", 1 },
- { "1", "3", 1 },
- { "1", "5", 1 },
- { "1", "7", 1 },
- { "1", "9", 1 },
- { "1", "11", 1 },
- /* (-1/b) = (-1)^((b-1)/2) which is -1 for b==3 mod 4 */
- { "-1", "1", 1 },
- { "-1", "3", -1 },
- { "-1", "5", 1 },
- { "-1", "7", -1 },
- { "-1", "9", 1 },
- { "-1", "11", -1 },
- { "-1", "13", 1 },
- { "-1", "15", -1 },
- { "-1", "17", 1 },
- { "-1", "19", -1 },
- /* (2/b) = (-1)^((b^2-1)/8) which is -1 for b==3,5 mod 8.
- try_2num() will exercise multiple powers of 2 in the numerator. */
- { "2", "1", 1 },
- { "2", "3", -1 },
- { "2", "5", -1 },
- { "2", "7", 1 },
- { "2", "9", 1 },
- { "2", "11", -1 },
- { "2", "13", -1 },
- { "2", "15", 1 },
- { "2", "17", 1 },
- /* (-2/b) = (-1)^((b^2-1)/8)*(-1)^((b-1)/2) which is -1 for b==5,7mod8.
- try_2num() will exercise multiple powers of 2 in the numerator, which
- will test that the shift in mpz_si_kronecker() uses unsigned not
- signed. */
- { "-2", "1", 1 },
- { "-2", "3", 1 },
- { "-2", "5", -1 },
- { "-2", "7", -1 },
- { "-2", "9", 1 },
- { "-2", "11", 1 },
- { "-2", "13", -1 },
- { "-2", "15", -1 },
- { "-2", "17", 1 },
- /* (a/2)=(2/a).
- try_2den() will exercise multiple powers of 2 in the denominator. */
- { "3", "2", -1 },
- { "5", "2", -1 },
- { "7", "2", 1 },
- { "9", "2", 1 },
- { "11", "2", -1 },
- /* Harriet Griffin, "Elementary Theory of Numbers", page 155, various
- examples. */
- { "2", "135", 1 },
- { "135", "19", -1 },
- { "2", "19", -1 },
- { "19", "135", 1 },
- { "173", "135", 1 },
- { "38", "135", 1 },
- { "135", "173", 1 },
- { "173", "5", -1 },
- { "3", "5", -1 },
- { "5", "173", -1 },
- { "173", "3", -1 },
- { "2", "3", -1 },
- { "3", "173", -1 },
- { "253", "21", 1 },
- { "1", "21", 1 },
- { "21", "253", 1 },
- { "21", "11", -1 },
- { "-1", "11", -1 },
- /* Griffin page 147 */
- { "-1", "17", 1 },
- { "2", "17", 1 },
- { "-2", "17", 1 },
- { "-1", "89", 1 },
- { "2", "89", 1 },
- /* Griffin page 148 */
- { "89", "11", 1 },
- { "1", "11", 1 },
- { "89", "3", -1 },
- { "2", "3", -1 },
- { "3", "89", -1 },
- { "11", "89", 1 },
- { "33", "89", -1 },
- /* H. Davenport, "The Higher Arithmetic", page 65, the quadratic
- residues and non-residues mod 19. */
- { "1", "19", 1 },
- { "4", "19", 1 },
- { "5", "19", 1 },
- { "6", "19", 1 },
- { "7", "19", 1 },
- { "9", "19", 1 },
- { "11", "19", 1 },
- { "16", "19", 1 },
- { "17", "19", 1 },
- { "2", "19", -1 },
- { "3", "19", -1 },
- { "8", "19", -1 },
- { "10", "19", -1 },
- { "12", "19", -1 },
- { "13", "19", -1 },
- { "14", "19", -1 },
- { "15", "19", -1 },
- { "18", "19", -1 },
- /* Residues and non-residues mod 13 */
- { "0", "13", 0 },
- { "1", "13", 1 },
- { "2", "13", -1 },
- { "3", "13", 1 },
- { "4", "13", 1 },
- { "5", "13", -1 },
- { "6", "13", -1 },
- { "7", "13", -1 },
- { "8", "13", -1 },
- { "9", "13", 1 },
- { "10", "13", 1 },
- { "11", "13", -1 },
- { "12", "13", 1 },
- /* various */
- { "5", "7", -1 },
- { "15", "17", 1 },
- { "67", "89", 1 },
- /* special values inducing a==b==1 at the end of jac_or_kron() */
- { "0x10000000000000000000000000000000000000000000000001",
- "0x10000000000000000000000000000000000000000000000003", 1 },
- };
- int i;
- mpz_t a, b;
- mpz_init (a);
- mpz_init (b);
- for (i = 0; i < numberof (data); i++)
- {
- mpz_set_str_or_abort (a, data[i].a, 0);
- mpz_set_str_or_abort (b, data[i].b, 0);
- try_all (a, b, data[i].answer);
- }
- mpz_clear (a);
- mpz_clear (b);
- }
- /* (a^2/b)=1 if gcd(a,b)=1, or (a^2/b)=0 if gcd(a,b)!=1.
- This includes when a=0 or b=0. */
- void
- check_squares_zi (void)
- {
- gmp_randstate_ptr rands = RANDS;
- mpz_t a, b, g;
- int i, answer;
- mp_size_t size_range, an, bn;
- mpz_t bs;
- mpz_init (bs);
- mpz_init (a);
- mpz_init (b);
- mpz_init (g);
- for (i = 0; i < 50; i++)
- {
- mpz_urandomb (bs, rands, 32);
- size_range = mpz_get_ui (bs) % 10 + 2;
- mpz_urandomb (bs, rands, size_range);
- an = mpz_get_ui (bs);
- mpz_rrandomb (a, rands, an);
- mpz_urandomb (bs, rands, size_range);
- bn = mpz_get_ui (bs);
- mpz_rrandomb (b, rands, bn);
- mpz_gcd (g, a, b);
- if (mpz_cmp_ui (g, 1L) == 0)
- answer = 1;
- else
- answer = 0;
- mpz_mul (a, a, a);
- try_all (a, b, answer);
- }
- mpz_clear (bs);
- mpz_clear (a);
- mpz_clear (b);
- mpz_clear (g);
- }
- /* Check the handling of asize==0, make sure it isn't affected by the low
- limb. */
- void
- check_a_zero (void)
- {
- mpz_t a, b;
- mpz_init_set_ui (a, 0);
- mpz_init (b);
- mpz_set_ui (b, 1L);
- PTR(a)[0] = 0;
- try_all (a, b, 1); /* (0/1)=1 */
- PTR(a)[0] = 1;
- try_all (a, b, 1); /* (0/1)=1 */
- mpz_set_si (b, -1L);
- PTR(a)[0] = 0;
- try_all (a, b, 1); /* (0/-1)=1 */
- PTR(a)[0] = 1;
- try_all (a, b, 1); /* (0/-1)=1 */
- mpz_set_ui (b, 0);
- PTR(a)[0] = 0;
- try_all (a, b, 0); /* (0/0)=0 */
- PTR(a)[0] = 1;
- try_all (a, b, 0); /* (0/0)=0 */
- mpz_set_ui (b, 2);
- PTR(a)[0] = 0;
- try_all (a, b, 0); /* (0/2)=0 */
- PTR(a)[0] = 1;
- try_all (a, b, 0); /* (0/2)=0 */
- mpz_clear (a);
- mpz_clear (b);
- }
- int
- main (int argc, char *argv[])
- {
- tests_start ();
- if (argc >= 2 && strcmp (argv[1], "-p") == 0)
- {
- option_pari = 1;
- printf ("
- try(a,b,answer) =n
- {n
- if (kronecker(a,b) != answer,n
- print("wrong at ", a, ",", b,n
- " expected ", answer,n
- " pari says ", kronecker(a,b)))n
- }n");
- }
- check_data ();
- check_squares_zi ();
- check_a_zero ();
- tests_end ();
- exit (0);
- }