diff options
author | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2010-08-17 09:10:13 +0000 |
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committer | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2010-08-17 09:10:13 +0000 |
commit | c9583bdfe064e1069828e518533f7bc29a8fdddb (patch) | |
tree | 2400842d4095628b8486fbeabaf7bc7b8af4ed02 /pow_si.c | |
parent | 50ac5b5985174201c7fa6e20496cd2b096107001 (diff) | |
download | mpfr-c9583bdfe064e1069828e518533f7bc29a8fdddb.tar.gz |
Source reorganization. In short:
* Added directories and moved related files into them:
- src for the MPFR source files (to build the library).
- doc for documentation files (except INSTALL, README...).
- tools for various tools (scripts) and mbench.
- tune for tuneup-related source files.
- other for other source files (not distributed in tarballs).
Existing directories:
- tests for the source files of the test suite (make check).
- examples for examples.
- m4 for m4 files.
* Renamed configure.in to configure.ac.
* Added/updated Makefile.am files where needed.
* Updated acinclude.m4 and configure.ac (AC_CONFIG_FILES line).
* Updated the documentation (INSTALL, README, doc/README.dev and
doc/mpfr.texi).
* Updated NEWS and TODO.
* Updated the scripts now in tools.
The following script was used:
#!/usr/bin/env zsh
svn mkdir doc other src tools tune
svn mv ${${(M)$(sed -n '/libmpfr_la_SOURCES/,/[^\]$/p' \
Makefile.am):#*.[ch]}:#get_patches.c} mparam_h.in \
round_raw_generic.c jyn_asympt.c src
svn mv mbench check_inits_clears coverage get_patches.sh mpfrlint \
nightly-test update-patchv update-version tools
svn mv bidimensional_sample.c speed.c tuneup.c tune
svn mv *.{c,h} other
svn mv FAQ.html README.dev algorithm* faq.xsl fdl.texi mpfr.texi \
update-faq doc
svn mv configure.in configure.ac
svn cp Makefile.am src/Makefile.am
svn rm replace_all
[Modifying some files, see above]
svn add doc/Makefile.am
svn add tune/Makefile.am
git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@7087 280ebfd0-de03-0410-8827-d642c229c3f4
Diffstat (limited to 'pow_si.c')
-rw-r--r-- | pow_si.c | 250 |
1 files changed, 0 insertions, 250 deletions
diff --git a/pow_si.c b/pow_si.c deleted file mode 100644 index 32c405acb..000000000 --- a/pow_si.c +++ /dev/null @@ -1,250 +0,0 @@ -/* mpfr_pow_si -- power function x^y with y a signed int - -Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. -Contributed by the Arenaire and Caramel projects, INRIA. - -This file is part of the GNU MPFR Library. - -The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LESSER. If not, see -http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., -51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ - -#define MPFR_NEED_LONGLONG_H -#include "mpfr-impl.h" - -/* The computation of y = pow_si(x,n) is done by - * y = pow_ui(x,n) if n >= 0 - * y = 1 / pow_ui(x,-n) if n < 0 - */ - -int -mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mpfr_rnd_t rnd) -{ - MPFR_LOG_FUNC (("x[%#R]=%R n=%ld rnd=%d", x, x, n, rnd), - ("y[%#R]=%R", y, y)); - - if (n >= 0) - return mpfr_pow_ui (y, x, n, rnd); - else - { - if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x))) - { - if (MPFR_IS_NAN (x)) - { - MPFR_SET_NAN (y); - MPFR_RET_NAN; - } - else if (MPFR_IS_INF (x)) - { - MPFR_SET_ZERO (y); - if (MPFR_IS_POS (x) || ((unsigned) n & 1) == 0) - MPFR_SET_POS (y); - else - MPFR_SET_NEG (y); - MPFR_RET (0); - } - else /* x is zero */ - { - MPFR_ASSERTD (MPFR_IS_ZERO (x)); - MPFR_SET_INF(y); - if (MPFR_IS_POS (x) || ((unsigned) n & 1) == 0) - MPFR_SET_POS (y); - else - MPFR_SET_NEG (y); - MPFR_RET(0); - } - } - - /* detect exact powers: x^(-n) is exact iff x is a power of 2 */ - if (mpfr_cmp_si_2exp (x, MPFR_SIGN(x), MPFR_EXP(x) - 1) == 0) - { - mpfr_exp_t expx = MPFR_EXP (x) - 1, expy; - MPFR_ASSERTD (n < 0); - /* Warning: n * expx may overflow! - * - * Some systems (apparently alpha-freebsd) abort with - * LONG_MIN / 1, and LONG_MIN / -1 is undefined. - * http://www.freebsd.org/cgi/query-pr.cgi?pr=72024 - * - * Proof of the overflow checking. The expressions below are - * assumed to be on the rational numbers, but the word "overflow" - * still has its own meaning in the C context. / still denotes - * the integer (truncated) division, and // denotes the exact - * division. - * - First, (__gmpfr_emin - 1) / n and (__gmpfr_emax - 1) / n - * cannot overflow due to the constraints on the exponents of - * MPFR numbers. - * - If n = -1, then n * expx = - expx, which is representable - * because of the constraints on the exponents of MPFR numbers. - * - If expx = 0, then n * expx = 0, which is representable. - * - If n < -1 and expx > 0: - * + If expx > (__gmpfr_emin - 1) / n, then - * expx >= (__gmpfr_emin - 1) / n + 1 - * > (__gmpfr_emin - 1) // n, - * and - * n * expx < __gmpfr_emin - 1, - * i.e. - * n * expx <= __gmpfr_emin - 2. - * This corresponds to an underflow, with a null result in - * the rounding-to-nearest mode. - * + If expx <= (__gmpfr_emin - 1) / n, then n * expx cannot - * overflow since 0 < expx <= (__gmpfr_emin - 1) / n and - * 0 > n * expx >= n * ((__gmpfr_emin - 1) / n) - * >= __gmpfr_emin - 1. - * - If n < -1 and expx < 0: - * + If expx < (__gmpfr_emax - 1) / n, then - * expx <= (__gmpfr_emax - 1) / n - 1 - * < (__gmpfr_emax - 1) // n, - * and - * n * expx > __gmpfr_emax - 1, - * i.e. - * n * expx >= __gmpfr_emax. - * This corresponds to an overflow (2^(n * expx) has an - * exponent > __gmpfr_emax). - * + If expx >= (__gmpfr_emax - 1) / n, then n * expx cannot - * overflow since 0 > expx >= (__gmpfr_emax - 1) / n and - * 0 < n * expx <= n * ((__gmpfr_emax - 1) / n) - * <= __gmpfr_emax - 1. - * Note: one could use expx bounds based on MPFR_EXP_MIN and - * MPFR_EXP_MAX instead of __gmpfr_emin and __gmpfr_emax. The - * current bounds do not lead to noticeably slower code and - * allow us to avoid a bug in Sun's compiler for Solaris/x86 - * (when optimizations are enabled); known affected versions: - * cc: Sun C 5.8 2005/10/13 - * cc: Sun C 5.8 Patch 121016-02 2006/03/31 - * cc: Sun C 5.8 Patch 121016-04 2006/10/18 - */ - expy = - n != -1 && expx > 0 && expx > (__gmpfr_emin - 1) / n ? - MPFR_EMIN_MIN - 2 /* Underflow */ : - n != -1 && expx < 0 && expx < (__gmpfr_emax - 1) / n ? - MPFR_EMAX_MAX /* Overflow */ : n * expx; - return mpfr_set_si_2exp (y, n % 2 ? MPFR_INT_SIGN (x) : 1, - expy, rnd); - } - - /* General case */ - { - /* Declaration of the intermediary variable */ - mpfr_t t; - /* Declaration of the size variable */ - mpfr_prec_t Ny; /* target precision */ - mpfr_prec_t Nt; /* working precision */ - mpfr_rnd_t rnd1; - int size_n; - int inexact; - unsigned long abs_n; - MPFR_SAVE_EXPO_DECL (expo); - MPFR_ZIV_DECL (loop); - - abs_n = - (unsigned long) n; - count_leading_zeros (size_n, (mp_limb_t) abs_n); - size_n = GMP_NUMB_BITS - size_n; - - /* initial working precision */ - Ny = MPFR_PREC (y); - Nt = Ny + size_n + 3 + MPFR_INT_CEIL_LOG2 (Ny); - - MPFR_SAVE_EXPO_MARK (expo); - - /* initialise of intermediary variable */ - mpfr_init2 (t, Nt); - - /* We will compute rnd(rnd1(1/x) ^ |n|), where rnd1 is the rounding - toward sign(x), to avoid spurious overflow or underflow, as in - mpfr_pow_z. */ - rnd1 = MPFR_EXP (x) < 1 ? MPFR_RNDZ : - (MPFR_SIGN (x) > 0 ? MPFR_RNDU : MPFR_RNDD); - - MPFR_ZIV_INIT (loop, Nt); - for (;;) - { - MPFR_BLOCK_DECL (flags); - - /* compute (1/x)^|n| */ - MPFR_BLOCK (flags, mpfr_ui_div (t, 1, x, rnd1)); - MPFR_ASSERTD (! MPFR_UNDERFLOW (flags)); - /* t = (1/x)*(1+theta) where |theta| <= 2^(-Nt) */ - if (MPFR_UNLIKELY (MPFR_OVERFLOW (flags))) - goto overflow; - MPFR_BLOCK (flags, mpfr_pow_ui (t, t, abs_n, rnd)); - /* t = (1/x)^|n|*(1+theta')^(|n|+1) where |theta'| <= 2^(-Nt). - If (|n|+1)*2^(-Nt) <= 1/2, which is satisfied as soon as - Nt >= bits(n)+2, then we can use Lemma \ref{lemma_graillat} - from algorithms.tex, which yields x^n*(1+theta) with - |theta| <= 2(|n|+1)*2^(-Nt), thus the error is bounded by - 2(|n|+1) ulps <= 2^(bits(n)+2) ulps. */ - if (MPFR_UNLIKELY (MPFR_OVERFLOW (flags))) - { - overflow: - MPFR_ZIV_FREE (loop); - mpfr_clear (t); - MPFR_SAVE_EXPO_FREE (expo); - MPFR_LOG_MSG (("overflow\n", 0)); - return mpfr_overflow (y, rnd, abs_n & 1 ? - MPFR_SIGN (x) : MPFR_SIGN_POS); - } - if (MPFR_UNLIKELY (MPFR_UNDERFLOW (flags))) - { - MPFR_ZIV_FREE (loop); - mpfr_clear (t); - MPFR_LOG_MSG (("underflow\n", 0)); - if (rnd == MPFR_RNDN) - { - mpfr_t y2, nn; - - /* We cannot decide now whether the result should be - rounded toward zero or away from zero. So, like - in mpfr_pow_pos_z, let's use the general case of - mpfr_pow in precision 2. */ - MPFR_ASSERTD (mpfr_cmp_si_2exp (x, MPFR_SIGN (x), - MPFR_EXP (x) - 1) != 0); - mpfr_init2 (y2, 2); - mpfr_init2 (nn, sizeof (long) * CHAR_BIT); - inexact = mpfr_set_si (nn, n, MPFR_RNDN); - MPFR_ASSERTN (inexact == 0); - inexact = mpfr_pow_general (y2, x, nn, rnd, 1, - (mpfr_save_expo_t *) NULL); - mpfr_clear (nn); - mpfr_set (y, y2, MPFR_RNDN); - mpfr_clear (y2); - MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, MPFR_FLAGS_UNDERFLOW); - goto end; - } - else - { - MPFR_SAVE_EXPO_FREE (expo); - return mpfr_underflow (y, rnd, abs_n & 1 ? - MPFR_SIGN (x) : MPFR_SIGN_POS); - } - } - /* error estimate -- see pow function in algorithms.ps */ - if (MPFR_LIKELY (MPFR_CAN_ROUND (t, Nt - size_n - 2, Ny, rnd))) - break; - - /* actualisation of the precision */ - MPFR_ZIV_NEXT (loop, Nt); - mpfr_set_prec (t, Nt); - } - MPFR_ZIV_FREE (loop); - - inexact = mpfr_set (y, t, rnd); - mpfr_clear (t); - - end: - MPFR_SAVE_EXPO_FREE (expo); - return mpfr_check_range (y, inexact, rnd); - } - } -} |