![[MPFR]](../mpfr100.png){kind=small}
The canard à l'orange release, patch level 4.
MPFR 3.1.4 requires GMP 4.1.0 or higher (GMP 4.2.3 or higher is recommended).
Note: the bug-fix release MPFR 3.1.5 is available. Please upgrade!
Warning! Due to the fact that Thread-Local Storage
(TLS) support is now detected
automatically, the MPFR build can be incorrect on some
platforms (compiler or system bug). Indeed,
the
TLS implementation of some compilers/platforms is buggy,
and MPFR cannot detect every problem at configure time.
Please run make check
to see if your build is affected.
If you get failures, you should try the --disable-thread-safe
configure option to disable TLS and see if this solves
these failures. But you should not use an MPFR library
with TLS disabled in a multithreaded program (unless
you know what you are doing).
The MPFR 3.1.4 source can be downloaded in the following archive formats:
Each tarball is signed by Vincent Lefèvre. This can be verified using the DSA key ID 98C3739D; this key can be retrieved with:
gpg --recv-keys 98C3739D
or by downloading it from https://www.vinc17.net/pgp.html. The key fingerprint is:
07F3 DBBE CC1A 3960 5078 094D 980C 1976 98C3 739D
The signatures can be verified with:
gpg --verify file.asc
You should check that the key fingerprint matches.
MPFR is also available via third-party packages and ports.
The bugs listed below have been fixed (latest update: 2016-09-12). The patches are distributed under the same license as this version of MPFR, that is, the GNU Lesser General Public License (GNU Lesser GPL), version 3 or later.
The following instructions are for Linux and may be similar for other operating systems. You can apply the patches in several ways:
patch -N -Z -p1 < path_to_patches_filefrom the source directory. The -N option allows the patch command to ignore patches already applied. The -Z option sets the modification time of the patched files from time stamps given in the patch file, thus avoiding the need of some development utilities (such as autoconf); this may generate a
Not setting timewarning for the PATCHES file, but you can safely ignore it. Under Microsoft Windows, in addition to the above options, you may need the --binary option (this depends whether the end-of-lines have been converted when you downloaded the patch file). Also note that the --dry-run option does not work if the cumulative patch has some file listed several times.
svn co svn://scm.gforge.inria.fr/svn/mpfr/branches/3.1 mpfr-3.1(Warning! No authentication is done.) In this case, as said on the Gforge page, you should read the README.dev file for details on how to build MPFR. Also note that the branch may contain additional minor fixes.
With the first two ways, the PATCHES file is modified,
so that one can know what patches have been applied, using the
mpfr_get_patches function. Moreover a suffix is added to
the version string, but note that for practical reasons, not all the
files where the version appears are patched; thus one can also track
applied patches with the MPFR_VERSION_STRING macro (header)
and the mpfr_get_version function (library). However, if
some patches are not applied or if patches are applied in a different
order, then the patch command will fail to update some chunks, so that
the suffix is not always reliable for patches.
Note: These patches are in unified diff format and some vendors' patch commands cannot deal with them; in this case, please use GNU patch (it may already be installed on your system, e.g. as /usr/local/bin/patch or gpatch).
Fixed bugs, with patches:
__unix__ macro is defined. This problem occurs in particular
with the 32-bit Cygwin. This is due to consistency checks added for
MPFR 3.1.4 (useful mainly for the developers). This
is fixed by the unix-check patch,
which just removes these checks (this is OK for the 3.1 branch, which
should now be stable enough, and in the trunk, the status of some macros
are output by tversion to replace these checks).mpfr_add_ui and mpfr_sub_ui
do not set all the expected flags; in practice, this concerns only the
NaN flag. This bug is fixed by
the add-sub-ui-flags patch, which
also provides test cases.mpfr_add on numbers of different signs and by
mpfr_sub on numbers of the same sign, i.e.
which does a = b − c with
|b| > |c|, is incorrect in the following case:
MPFR_RNDN (round-to-nearest mode);mpfr_can_round_raw internal rounding-test
function, used by the mpfr_can_round public function, is still
buggy: there had already been a patch for MPFR 3.1.3,
applied in MPFR 3.1.4, which fixed some particular
cases, but new bugs have recently been found. This function still has
false positives in some cases, i.e. it can return true
(meaning that correct rounding is possible) instead of false (meaning
that correct rounding is not guaranteed). It also has false negatives,
some of which can yield infinite Ziv loops in user code in practice.
Some MPFR math functions might be affected by
false positives, but most of them use other internal methods
instead of this function. This bug is fixed by the
can_round2 patch, which also
provides test cases (in particular a comprehensive test against
a naive implementation).#include <stdio.h>
#include <mpfr.h>
int main (void)
{
mpfr_t x;
int r;
mpfr_init2 (x, 3);
mpfr_set_ui (x, 5, MPFR_RNDN);
r = mpfr_can_round (x, 4, MPFR_RNDN, MPFR_RNDN, 3);
printf ("%d\n", r);
mpfr_clear (x);
return 0;
}
Here, the number 5 is an approximation to an unknown number in the interval
[5 − 1/2, 5 + 1/2]. In round-to-nearest (with the even rounding rule)
and the target precision 3, the number 5 − 1/2 rounds to 4, while
the number 5 + 1/2 rounds to 6. Thus the program should output 0, but with
MPFR 3.1.4, one gets 1.mpfr_get_ld function does not round correctly in the
subnormal range due to an incorrect value of the minimum exponent. This
is fixed by the get_ld patch.Other bugs: See the tracker and the BUGS file.
MPFR 3.1.4 has been successfully compiled and checked on the following platforms: