1Mathematical and scientific constants 2===================================== 3 4In this module some usefull constants are defined. There are four groups 5of constants: 6 7- mathematical, 8 9- physical in mks unit system, 10 11- physical in cgs unit system and 12 13- physical number constants (e.g. fine structure) 14 15The other modules are created during the initialisation of . For 16convenience the mathematical, physical mks constants and number 17constants also are available in the namespace of . If the used GSL 18version is before gsl1.4, see 19 20:: 21 22 pygsl.compiled_gsl_version 23 24than the module names are cgs and mks. Form gsl1.5 these modules have 25been renamed to cgsm and mksa. So to use cgs constants one has to write 26 27:: 28 29 import pygsl.const 30 import pygsl.const.cgs 31 print pygsl.const.cgs.speed_of_light/pygsl.const.speed_of_light 32 33for gsl :math:`<` 1.5 and 34 35:: 36 37 import pygsl.const 38 import pygsl.const.cgsm 39 print pygsl.const.cgsm.speed_of_light/pygsl.const.speed_of_light 40 41. Of course the result is . Short examples are given at top of each 42section. 43 44The actual values are taken form the GSL headers. The GNU Scientific 45Library reference provides a more detailed description of these 46constants. 47 48Mathematical constants 49---------------------- 50 51:: 52 53 from pygsl.const.m import * 54 print sqrt2*sqrt2 55 56| 57| Prints . 58| Here comes the list: 59 60l\|l\|lconstantNameGSL Namevalue 61 62Scientific constants in mksa units 63---------------------------------- 64 65:: 66 67 from pygsl.const import cgsm 68 print "a teaspoon contains %g m^3"%mks.teaspoon 69 70These are the provided constants: 71 72l\|l\|lconstantNamegsl Nameunit 73 74Scientific constants in cgsm units 75---------------------------------- 76 77:: 78 79 from pygsl.const import cgsm 80 print "a teaspoon contains %g ml"%cgs.teaspoon 81 82You can access the following constants: 83 84l\|l\|lconstantNamegsl Nameunit or value 85 86Scientific number constants 87--------------------------- 88 89:: 90 91 from pygsl.const import * 92 # an alternative to 93 # from pygsl.const.num import * 94 print "fine structure is 1/137 with an error of %g%%"%(abs(1.0/137.0/fine_structure-1.0)*100.0) 95 96Only two constants are available: 97 98l\|l\|lconstantNamegsl Nameunit 99