PyCRlibm - Python bindings for CRlibm

Python bindings for CRlibm, an efficient and proven correctly-rounded mathematical library.

CRlibm is a free mathematical library (libm) which provides:

implementations of the double-precision C99 standard elementary functions,
correctly rounded in the four IEEE-754 rounding modes,
with a comprehensive proof of both the algorithms used and their implementation,
sufficiently efficient in average time, worst-case time, and memory consumption to replace existing libms transparently.

Installation

At the command line:

$ pip install crlibm

On Microsoft Windows pip will try first to download a binary archive in wheel format, and if no such a wheel can be found for your Python version, pip will try to compile the library. In order to do so, it is strongly recommended to have MinGW-w64 installed under MSYS2, for instance by following the instructions in http://stackoverflow.com/a/30071634.

Usage

In Python:

>>> import crlibm
>>> crlibm.exp_ru(1)
2.7182818284590455

>>> crlibm.exp_rd(1)
2.718281828459045

Features

This project provides the bindings for the functions in the following table:

f(x)	Round to nearest	Round up (to +∞)	Round down (to -∞)	Round to 0
Exponentials and logarithms
exp(x)	exp_rn	exp_ru	exp_rd	exp_rz
exp(x)-1	expm1_rn	expm1_ru	expm1_rd	expm1_rz
log(x)	log_rn	log_ru	log_rd	log_rz
log(1+x)	log1p_rn	log1p_ru	log1p_rd	log1p_rz
log(x)/log(2)	log2_rn	log2_ru	log2_rd	log2_rz
log(x)/log(10)	log10_rn	log10_ru	log10_rd	log10_rz
sinh(x)	sinh_rn	sinh_ru	sinh_rd	sinh_rz
cosh(x)	cosh_rn	cosh_ru	cosh_rd	cosh_rz
Trigonometry
sin(x)	sin_rn	sin_ru	sin_rd	sin_rz
cos(x)	cos_rn	cos_ru	cos_rd	cos_rz
tan(x)	tan_rn	tan_ru	tan_rd	tan_rz
asin(x)	asin_rn	asin_ru	asin_rd	asin_rz
acos(x)	acos_rn	acos_ru	acos_rd	acos_rz
atan(x)	atan_rn	atan_ru	atan_rd	atan_rz
Trigonometry in multiples of π
sin(π * x)	sinpi_rn	sinpi_ru	sinpi_rd	sinpi_rz
cos(π * x)	cospi_rn	cospi_ru	cospi_rd	cospi_rz
tan(π * x)	tanpi_rn	tanpi_ru	tanpi_rd	tanpi_rz
asin(x)/π	asinpi_rn	asinpi_ru	asinpi_rd	asinpi_rz
acos(x)/π	acospi_rn	acospi_ru	acospi_rd	acospi_rz
atan(x)/π	atanpi_rn	atanpi_ru	atanpi_rd	atanpi_rz

The function pow in CRlibm is not exported.

License

Both the CRlibm library and the Python bindings are distributed under the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

Authors

David Defour, Catherine Daramy, Florent de Dinechin, Matthieu Gallet, Nicolas Gast, Christoph Lauter, Jean-Michel Muller.

Python bindings by Stefano Taschini.