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authorvlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4>2010-08-17 09:10:13 +0000
committervlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4>2010-08-17 09:10:13 +0000
commitc9583bdfe064e1069828e518533f7bc29a8fdddb (patch)
tree2400842d4095628b8486fbeabaf7bc7b8af4ed02 /src/asin.c
parent50ac5b5985174201c7fa6e20496cd2b096107001 (diff)
downloadmpfr-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 'src/asin.c')
-rw-r--r--src/asin.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/src/asin.c b/src/asin.c
new file mode 100644
index 000000000..3ef78f06d
--- /dev/null
+++ b/src/asin.c
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+/* mpfr_asin -- arc-sinus of a floating-point number
+
+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, and was contributed by Mathieu Dutour.
+
+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. */
+
+#include "mpfr-impl.h"
+
+int
+mpfr_asin (mpfr_ptr asin, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
+{
+ mpfr_t xp;
+ int compared, inexact;
+ mpfr_prec_t prec;
+ mpfr_exp_t xp_exp;
+ MPFR_SAVE_EXPO_DECL (expo);
+ MPFR_ZIV_DECL (loop);
+
+ MPFR_LOG_FUNC (("x[%#R]=%R rnd=%d", x, x, rnd_mode),
+ ("asin[%#R]=%R inexact=%d", asin, asin, inexact));
+
+ /* Special cases */
+ if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
+ {
+ if (MPFR_IS_NAN (x) || MPFR_IS_INF (x))
+ {
+ MPFR_SET_NAN (asin);
+ MPFR_RET_NAN;
+ }
+ else /* x = 0 */
+ {
+ MPFR_ASSERTD (MPFR_IS_ZERO (x));
+ MPFR_SET_ZERO (asin);
+ MPFR_SET_SAME_SIGN (asin, x);
+ MPFR_RET (0); /* exact result */
+ }
+ }
+
+ /* asin(x) = x + x^3/6 + ... so the error is < 2^(3*EXP(x)-2) */
+ MPFR_FAST_COMPUTE_IF_SMALL_INPUT (asin, x, -2 * MPFR_GET_EXP (x), 2, 1,
+ rnd_mode, {});
+
+ /* Set x_p=|x| (x is a normal number) */
+ mpfr_init2 (xp, MPFR_PREC (x));
+ inexact = mpfr_abs (xp, x, MPFR_RNDN);
+ MPFR_ASSERTD (inexact == 0);
+
+ compared = mpfr_cmp_ui (xp, 1);
+
+ if (MPFR_UNLIKELY (compared >= 0))
+ {
+ mpfr_clear (xp);
+ if (compared > 0) /* asin(x) = NaN for |x| > 1 */
+ {
+ MPFR_SET_NAN (asin);
+ MPFR_RET_NAN;
+ }
+ else /* x = 1 or x = -1 */
+ {
+ if (MPFR_IS_POS (x)) /* asin(+1) = Pi/2 */
+ inexact = mpfr_const_pi (asin, rnd_mode);
+ else /* asin(-1) = -Pi/2 */
+ {
+ inexact = -mpfr_const_pi (asin, MPFR_INVERT_RND(rnd_mode));
+ MPFR_CHANGE_SIGN (asin);
+ }
+ mpfr_div_2ui (asin, asin, 1, rnd_mode); /* May underflow */
+ return inexact;
+ }
+ }
+
+ MPFR_SAVE_EXPO_MARK (expo);
+
+ /* Compute exponent of 1 - ABS(x) */
+ mpfr_ui_sub (xp, 1, xp, MPFR_RNDD);
+ MPFR_ASSERTD (MPFR_GET_EXP (xp) <= 0);
+ MPFR_ASSERTD (MPFR_GET_EXP (x) <= 0);
+ xp_exp = 2 - MPFR_GET_EXP (xp);
+
+ /* Set up initial prec */
+ prec = MPFR_PREC (asin) + 10 + xp_exp;
+
+ /* use asin(x) = atan(x/sqrt(1-x^2)) */
+ MPFR_ZIV_INIT (loop, prec);
+ for (;;)
+ {
+ mpfr_set_prec (xp, prec);
+ mpfr_sqr (xp, x, MPFR_RNDN);
+ mpfr_ui_sub (xp, 1, xp, MPFR_RNDN);
+ mpfr_sqrt (xp, xp, MPFR_RNDN);
+ mpfr_div (xp, x, xp, MPFR_RNDN);
+ mpfr_atan (xp, xp, MPFR_RNDN);
+ if (MPFR_LIKELY (MPFR_CAN_ROUND (xp, prec - xp_exp,
+ MPFR_PREC (asin), rnd_mode)))
+ break;
+ MPFR_ZIV_NEXT (loop, prec);
+ }
+ MPFR_ZIV_FREE (loop);
+ inexact = mpfr_set (asin, xp, rnd_mode);
+
+ mpfr_clear (xp);
+
+ MPFR_SAVE_EXPO_FREE (expo);
+ return mpfr_check_range (asin, inexact, rnd_mode);
+}