root.c
上传用户:qaz666999
上传日期:2022-08-06
资源大小:2570k
文件大小:2k
- /* mpz_root(root, u, nth) -- Set ROOT to floor(U^(1/nth)).
- Return an indication if the result is exact.
- Copyright 1999, 2000, 2001, 2002, 2003, 2005 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/. */
- #include <stdio.h> /* for NULL */
- #include "gmp.h"
- #include "gmp-impl.h"
- int
- mpz_root (mpz_ptr root, mpz_srcptr u, unsigned long int nth)
- {
- mp_ptr rootp, up;
- 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;
- return 1; /* exact result */
- }
- 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);
- up = PTR(u);
- if (nth == 1)
- {
- MPN_COPY (rootp, up, un);
- remn = 0;
- }
- else
- {
- remn = mpn_rootrem (rootp, NULL, up, un, (mp_limb_t) nth);
- }
- if (root != NULL)
- {
- SIZ(root) = us >= 0 ? rootn : -rootn;
- if (u == root)
- MPN_COPY (up, rootp, rootn);
- }
- TMP_FREE;
- return remn == 0;
- }