[atan.c] implemented argument reduction (cf error analysis in algorithms.tex)

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@6483 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 4 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index be4e95390..497d06d3c 100644
--- a/NEWS
+++ b/NEWS
@@ -35,8 +35,10 @@ _ The rounding mode type mp_rnd_t is now mpfr_rnd_t (mp_rnd_t kept for
 - New function mpfr_digamma.
 - New functions mpfr_set_flt and mpfr_get_flt to convert from/to the float type
 - Speed improvement for large operands in the trigonometric functions
-  (mpfr_sin, mpfr_cos, mpfr_tan, mpfr_sin_cos): speedup of more than 3 for
-  10^5 digits, of more than 6 for 10^6 digits
+  (mpfr_sin, mpfr_cos, mpfr_tan, mpfr_sin_cos): speedup of about 2.5 for
+  10^5 digits, of about 5 for 10^6 digits.
+- Speed improvement for large operands of the inverse trigonometric functions
+  (arcsin, arccos, arctan): about 2 for 10^3 digits, up to 2.7 for 10^6 digits
 - Some documentation files are installed in $docdir.
 - Bug fixes.