85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
/* mpz_lcm -- mpz/mpz least common multiple.
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Copyright 1996, 2000, 2001, 2005 Free Software Foundation, 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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#include "longlong.h"
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void
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mpz_lcm (mpz_ptr r, mpz_srcptr u, mpz_srcptr v)
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{
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mpz_t g;
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mp_size_t usize, vsize, size;
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TMP_DECL;
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usize = SIZ (u);
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vsize = SIZ (v);
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if (usize == 0 || vsize == 0)
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{
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SIZ (r) = 0;
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return;
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}
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usize = ABS (usize);
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vsize = ABS (vsize);
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if (vsize == 1)
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{
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mp_limb_t vl, gl, c;
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mp_srcptr up;
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mp_ptr rp;
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one:
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MPZ_REALLOC (r, usize+1);
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up = PTR(u);
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vl = PTR(v)[0];
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gl = mpn_gcd_1 (up, usize, vl);
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vl /= gl;
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rp = PTR(r);
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c = mpn_mul_1 (rp, up, usize, vl);
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rp[usize] = c;
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usize += (c != 0);
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SIZ(r) = usize;
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return;
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}
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if (usize == 1)
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{
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usize = vsize;
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MPZ_SRCPTR_SWAP (u, v);
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goto one;
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}
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TMP_MARK;
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size = MAX (usize, vsize);
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MPZ_TMP_INIT (g, size);
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mpz_gcd (g, u, v);
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mpz_divexact (g, u, g);
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mpz_mul (r, g, v);
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SIZ (r) = ABS (SIZ (r)); /* result always positive */
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TMP_FREE;
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}
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