1
/* mpz_remove -- divide out a factor and return its multiplicity.
3
Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
5
This file is part of the GNU MP Library.
7
The GNU MP Library is free software; you can redistribute it and/or modify
8
it under the terms of the GNU Lesser General Public License as published by
9
the Free Software Foundation; either version 2.1 of the License, or (at your
10
option) any later version.
12
The GNU MP Library is distributed in the hope that it will be useful, but
13
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15
License for more details.
17
You should have received a copy of the GNU Lesser General Public License
18
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20
MA 02111-1307, USA. */
26
mpz_remove (mpz_ptr dest, mpz_srcptr src, mpz_srcptr f)
28
mpz_t fpow[40]; /* inexhaustible...until year 2020 or so */
30
unsigned long int pwr;
33
if (mpz_cmp_ui (f, 1) <= 0 || mpz_sgn (src) == 0)
35
if (mpz_cmp_ui (f, 2) == 0)
38
s0 = mpz_scan1 (src, 0);
39
mpz_div_2exp (dest, src, s0);
43
/* We could perhaps compute mpz_scan1(src,0)/mpz_scan1(f,0). It is an
44
upper bound of the result we're seeking. We could also shift down the
45
operands so that they become odd, to make intermediate values smaller. */
55
/* Divide by f, f^2, ..., f^(2^k) until we get a remainder for f^(2^k). */
58
mpz_tdiv_qr (x, rem, dest, fpow[p]);
61
mpz_init (fpow[p + 1]);
62
mpz_mul (fpow[p + 1], fpow[p], fpow[p]);
70
/* Divide by f^(2^(k-1)), f^(2^(k-2)), ..., f for all divisors that give a
74
mpz_tdiv_qr (x, rem, dest, fpow[p]);