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| author | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2016-01-15 16:30:07 +0000 |
|---|---|---|
| committer | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2016-01-15 16:30:07 +0000 |
| commit | b12a5184c074f0756527379522df35e5357ae68c (patch) | |
| tree | 5dd88b9613f5d61d8198b41491e5c77e27cac09d /src/log_ui.c | |
| parent | 63a259b9bf33378c006631f2420fa377b87dcdec (diff) | |
| download | mpfr-b12a5184c074f0756527379522df35e5357ae68c.tar.gz | |
[src/log_ui.c] Added a FIXME comment: mpfr_log_ui is much slower than
mpfr_log on some values of n, e.g. around ULONG_MAX/3.
git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@9819 280ebfd0-de03-0410-8827-d642c229c3f4
Diffstat (limited to 'src/log_ui.c')
| -rw-r--r-- | src/log_ui.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/log_ui.c b/src/log_ui.c index ad0b485dc..e96fe5f83 100644 --- a/src/log_ui.c +++ b/src/log_ui.c @@ -23,6 +23,10 @@ http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., #define MPFR_NEED_LONGLONG_H #include "mpfr-impl.h" +/* FIXME: mpfr_log_ui is much slower than mpfr_log on some values of n, + e.g. something like 8 times as slow for n around ULONG_MAX/3 on an + x86_64 Linux machine. */ + /* Auxiliary function: Compute using binary splitting the sum -sum((-x)^(n+1-n1)/n, n = n1..n2-1) where x = p/2^k, -1/3 <= x <= 1/3. For n1=1 we get -sum((-x)^n/n, n = 1..n2-1). |