93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
/* mpz_rootrem(root, rem, u, nth) -- Set ROOT to floor(U^(1/nth)) and
|
|
set REM to the remainder.
|
|
|
|
Copyright 1999, 2000, 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
|
|
|
|
Copyright 2010 Dr B R Gladman
|
|
|
|
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/. */
|
|
|
|
#include <stdio.h> /* for NULL */
|
|
#include "mpir.h"
|
|
#include "gmp-impl.h"
|
|
|
|
void
|
|
mpz_rootrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr u, gmp_ui nth)
|
|
{
|
|
mp_ptr rootp, up, remp;
|
|
mp_size_t us, un, rootn, remn;
|
|
TMP_DECL;
|
|
|
|
us = SIZ(u);
|
|
|
|
/* even roots of negatives provoke an exception */
|
|
if (us < 0 && (nth & 1) == 0)
|
|
SQRT_OF_NEGATIVE;
|
|
|
|
/* root extraction interpreted as c^(1/nth) means a zeroth root should
|
|
provoke a divide by zero, do this even if c==0 */
|
|
if (nth == 0)
|
|
DIVIDE_BY_ZERO;
|
|
|
|
if (us == 0)
|
|
{
|
|
if (root != NULL)
|
|
SIZ(root) = 0;
|
|
SIZ(rem) = 0;
|
|
return;
|
|
}
|
|
|
|
un = ABS (us);
|
|
rootn = (un - 1) / nth + 1;
|
|
|
|
TMP_MARK;
|
|
|
|
/* FIXME: Perhaps disallow root == NULL */
|
|
if (root != NULL && u != root)
|
|
rootp = MPZ_REALLOC (root, rootn);
|
|
else
|
|
rootp = TMP_ALLOC_LIMBS (rootn);
|
|
|
|
if (u != rem)
|
|
remp = MPZ_REALLOC (rem, un);
|
|
else
|
|
remp = TMP_ALLOC_LIMBS (un);
|
|
|
|
up = PTR(u);
|
|
|
|
if (nth == 1)
|
|
{
|
|
MPN_COPY (rootp, up, un);
|
|
remn = 0;
|
|
}
|
|
else
|
|
{
|
|
remn = mpn_rootrem (rootp, remp, up, un, (mp_limb_t) nth);
|
|
}
|
|
|
|
if (root != NULL)
|
|
{
|
|
SIZ(root) = us >= 0 ? rootn : -rootn;
|
|
if (u == root)
|
|
MPN_COPY (up, rootp, rootn);
|
|
else if (u == rem)
|
|
MPN_COPY (up, remp, remn);
|
|
}
|
|
|
|
SIZ(rem) = us < 0 && remn > 0 ? -remn : remn;
|
|
TMP_FREE;
|
|
}
|