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CariBlog – Blog on Vincent Lefèvre's Research Pages and Computer Arithmetic

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[2017-08-01 20:13:40 UTC]
Patch 10 for GNU MPFR 3.1.5

(CariBlog – MPFR – Software)

Patch 10 of GNU MPFR 3.1.5 is available in the bugs section of the MPFR 3.1.5 page. It fixes incorrect header inclusion introduced by patch 8, in order to get the correct definition of symbols and avoid a link-time error under Microsoft Windows with DLL.

[2017-07-22 07:34:55 UTC]
Patch 9 for GNU MPFR 3.1.5

(CariBlog – MPFR – Software)

Patch 9 of GNU MPFR 3.1.5 is available in the bugs section of the MPFR 3.1.5 page. It fixes a very important bug for users of platforms with a 32-bit unsigned long (32-bit ABI or Microsoft Windows) for very high precisions: computations in sin_cos.c suffer from overflows in such precisions (more than about 1,000,000 bits) due to the limited size of the unsigned long type. In practice, this introduces an error of up to 2−1019574 approximately, so that the trigonometric functions (mpfr_sin, mpfr_cos, mpfr_tan) and functions that call them can be very inaccurate (limiting the overall accuracy to about one million bits for these functions on such platforms).

[2017-06-07 21:51:03 UTC]
Patches 3 to 8 for GNU MPFR 3.1.5

(CariBlog – MPFR – Software)

Patches 3 to 8 of GNU MPFR 3.1.5 are available in the bugs section of the MPFR 3.1.5 page. The first five fix minor issues and patch 8 fixes some mpf2mpfr.h macros (only users of this header file, used to build GMP/mpf programs with MPFR instead of mpf, may be affected).

[2017-04-10 11:44:15 UTC]
My Latest Publications

(CariBlog – MPFR)

I have two new papers that have just been accepted, both related to GNU MPFR.

[2017-02-17 16:19:10 UTC]
Status of the GNU MPFR Trunk

(CariBlog – MPFR – Software)

For those who test the GNU MPFR trunk via Subversion on InriaForge:

  • The tzeta test should no longer fail on most platforms (IEEE 754 machines with default IEEE exception handling).

  • The tsprintf test still fails (fix in progress). The cause is a major efficiency issue in particular cases (huge precision requested).

Note: Both problems are also present in the released versions, but they have no tests that trigger them.

[2016-12-26 00:07:32 UTC]
Patch 2 for GNU MPFR 3.1.5

(CariBlog – MPFR – Software)

Patch 2 of GNU MPFR 3.1.5 is available in the bugs section of the MPFR 3.1.5 page. It fixes the following bug. The mpfr_strtofr function can return an incorrect ternary value in the round-to-nearest mode (MPFR_RNDN).

[2016-12-15 17:57:00 UTC]
Patch 1 for GNU MPFR 3.1.5

(CariBlog – MPFR – Software)

Patch 1 of GNU MPFR 3.1.5 is available in the bugs section of the MPFR 3.1.5 page. It fixes the following bug. The formatted output functions (mpfr_*printf) yield an undefined behavior or assertion failure when a precision less than −1 is given as an argument for the f or F conversion specifier (the given precision should have been ignored).

[2016-09-27 17:44:06 UTC]
GNU MPFR 3.1.5 is Released

(CariBlog – MPFR – Software)

The GNU MPFR 3.1.5 library (canard à l'orange, patch level 5) has been released. The changes from version 3.1.4:

[2016-09-12 21:29:25 UTC]
Patches 5 and 6 for GNU MPFR 3.1.4

(CariBlog – MPFR – Software)

Patches 5 and 6 of GNU MPFR 3.1.4 are available in the bugs section of the MPFR 3.1.4 page. Patch 5 fixes bugs in the mpfr_can_round_raw internal rounding-test function, used by the mpfr_can_round public function (in particular, the few MPFR math functions that use this rounding test might be rounded incorrectly). Patch 6 fixes the mpfr_get_ld function, which did not round correctly in the subnormal range on x86 platforms.

[2016-08-05 19:58:20 UTC]
Patch 4 for GNU MPFR 3.1.4

(CariBlog – MPFR – Software)

Patch 4 of GNU MPFR 3.1.4 is available in the bugs section of the MPFR 3.1.4 page. It fixes an incompatibility of some programs of the test suite with the C++11 standard (used by default with g++ from GCC 6) and is useful only for those who compile MPFR with such a C++ compiler (instead of a C compiler).

[2016-07-17 15:11:29 UTC]
My ARITH-23 Article and Slides: Correctly Rounded Arbitrary-Precision Floating-Point Summation

(CariBlog – MPFR)

A few days ago, I presented my paper Correctly Rounded Arbitrary-Precision Floating-Point Summation at the 23rd IEEE Symposium on Computer Arithmetic (ARITH 23), which took place from July 10 to July 13, 2016, in Santa Clara, California, USA. The goal of this work was a complete rewrite of the mpfr_sum function for the next GNU MPFR release (version 4.0.0). Here are links to my article and my slides.

Note that I did some improvements since I wrote the article. The slides are more up-to-date, covering the current mpfr_sum function (r10503) at this time. The current sum.txt file (r10523) contains more details, but it is still not up-to-date (like the article).

[2016-06-13 17:34:22 UTC]
Patch 3 for GNU MPFR 3.1.4

(CariBlog – MPFR – Software)

Patch 3 of GNU MPFR 3.1.4 is available in the bugs section of the MPFR 3.1.4 page. It fixes a bug in the subtraction code (addition of two numbers of different signs or subtraction of two numbers of the same sign), which can give an overflow on some very particular case while it should not (see the link for details). It is very unlikely that an application would be affected by the bug.

I discovered this bug while I was reviewing a part of the code to implement unbounded-float support (floating-point numbers with an unbounded exponent range) in order to avoid intermediate overflows for functions like mpfr_fmma (which computes a·b + c·d) or possibly in the future, polynomial evaluation with correct rounding.

[2016-05-26 21:50:50 UTC]
Patches 1 and 2 for GNU MPFR 3.1.4

(CariBlog – MPFR – Software)

Patches 1 and 2 of GNU MPFR 3.1.4 are available in the bugs section of the MPFR 3.1.4 page. The first one concerns users of the 32-bit Cygwin (under Microsoft Windows). The second one fixes flags setting in functions mpfr_add_ui and mpfr_sub_ui; in practice, the only issue is that the NaN flag is not set with a NaN input.

I take the opportunity to point out that it was decided at the MPFR developer meeting of May 23-24 that the next MPFR release will be 4.0.

[2016-03-06 23:57:16 UTC]
GNU MPFR 3.1.4 is Released

(CariBlog – MPFR – Software)

The GNU MPFR 3.1.4 library (canard à l'orange, patch level 4) has been released. The changes from version 3.1.3: improved manual, bug fixes (detailed list on the MPFR 3.1.3 page and ChangeLog file), and support for thread-safe DLL (shared library) with MinGW (for Microsoft Windows).

[2016-02-29 23:43:44 UTC]
Patches 13 to 17 for GNU MPFR 3.1.3 and GNU MPFR 3.1.4 Release Candidate 2

(CariBlog – MPFR – Software)

Patches 13 to 17 of GNU MPFR 3.1.3 are available in the bugs section of the MPFR 3.1.3 page.

The second GNU MPFR 3.1.4 release candidate is also available.



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