69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
/* mpq_mul -- multiply two rational numbers.
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Copyright 1991, 1994, 1995, 1996, 2000, 2001, 2002 Free Software Foundation,
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Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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void
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mpq_mul (mpq_ptr prod, mpq_srcptr op1, mpq_srcptr op2)
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{
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mpz_t gcd1, gcd2;
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mpz_t tmp1, tmp2;
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if (op1 == op2)
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{
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/* No need for any GCDs when squaring. */
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mpz_mul (mpq_numref (prod), mpq_numref (op1), mpq_numref (op1));
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mpz_mul (mpq_denref (prod), mpq_denref (op1), mpq_denref (op1));
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return;
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}
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mpz_init (gcd1);
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mpz_init (gcd2);
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mpz_init (tmp1);
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mpz_init (tmp2);
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/* PROD might be identical to either operand, so don't store the
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result there until we are finished with the input operands. We
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dare to overwrite the numerator of PROD when we are finished
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with the numerators of OP1 and OP2. */
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mpz_gcd (gcd1, &(op1->_mp_num), &(op2->_mp_den));
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mpz_gcd (gcd2, &(op2->_mp_num), &(op1->_mp_den));
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mpz_divexact_gcd (tmp1, &(op1->_mp_num), gcd1);
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mpz_divexact_gcd (tmp2, &(op2->_mp_num), gcd2);
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mpz_mul (&(prod->_mp_num), tmp1, tmp2);
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mpz_divexact_gcd (tmp1, &(op2->_mp_den), gcd1);
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mpz_divexact_gcd (tmp2, &(op1->_mp_den), gcd2);
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mpz_mul (&(prod->_mp_den), tmp1, tmp2);
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mpz_clear (tmp2);
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mpz_clear (tmp1);
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mpz_clear (gcd2);
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mpz_clear (gcd1);
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}
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