Mathematical and scientific constants

In this module some usefull constants are defined. There are four groups of constants:

  • mathematical,

  • physical in mks unit system,

  • physical in cgs unit system and

  • physical number constants (e.g. fine structure)

The other modules are created during the initialisation of . For convenience the mathematical, physical mks constants and number constants also are available in the namespace of . If the used GSL version is before gsl1.4, see

pygsl.compiled_gsl_version

than the module names are cgs and mks. Form gsl1.5 these modules have been renamed to cgsm and mksa. So to use cgs constants one has to write

import pygsl.const
import pygsl.const.cgs
print pygsl.const.cgs.speed_of_light/pygsl.const.speed_of_light

for gsl \(<\) 1.5 and

import pygsl.const
import pygsl.const.cgsm
print pygsl.const.cgsm.speed_of_light/pygsl.const.speed_of_light

. Of course the result is . Short examples are given at top of each section.

The actual values are taken form the GSL headers. The GNU Scientific Library reference provides a more detailed description of these constants.

Mathematical constants

from pygsl.const.m import *
print sqrt2*sqrt2

Prints .
Here comes the list:

l|l|lconstantNameGSL Namevalue

Scientific constants in mksa units

from pygsl.const import cgsm
print "a teaspoon contains %g m^3"%mks.teaspoon

These are the provided constants:

l|l|lconstantNamegsl Nameunit

Scientific constants in cgsm units

from pygsl.const import cgsm
print "a teaspoon contains %g ml"%cgs.teaspoon

You can access the following constants:

l|l|lconstantNamegsl Nameunit or value

Scientific number constants

from pygsl.const import *
# an alternative to
# from pygsl.const.num import *
print "fine structure is 1/137 with an error of %g%%"%(abs(1.0/137.0/fine_structure-1.0)*100.0)

Only two constants are available:

l|l|lconstantNamegsl Nameunit