diff options
Diffstat (limited to 'vendor/gmp-6.3.0/mpz/root.c')
-rw-r--r-- | vendor/gmp-6.3.0/mpz/root.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpz/root.c b/vendor/gmp-6.3.0/mpz/root.c new file mode 100644 index 0000000..7c8d368 --- /dev/null +++ b/vendor/gmp-6.3.0/mpz/root.c @@ -0,0 +1,90 @@ +/* mpz_root(root, u, nth) -- Set ROOT to floor(U^(1/nth)). + Return an indication if the result is exact. + +Copyright 1999-2003, 2005, 2012, 2020 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 either: + + * 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. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +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 General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include <stdio.h> /* for NULL */ +#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 (UNLIKELY (us < 0 && (nth & 1) == 0)) + SQRT_OF_NEGATIVE; + + if (UNLIKELY (nth <= 1)) + { + /* root extraction interpreted as c^(1/nth) means a zeroth root should + provoke a divide by zero, do this even if c==0 */ + if (UNLIKELY (nth == 0)) + DIVIDE_BY_ZERO; + /* nth == 1 */ + if (root != NULL && u != root) + mpz_set (root, u); + return 1; /* exact result */ + } + + 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_NEWALLOC (root, rootn); + else + rootp = TMP_ALLOC_LIMBS (rootn); + + up = PTR(u); + 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; +} |