Declared in module bhoelHelper
def machar() string __author__ = 'Berthold H\366llmann, bhoel@starship.python.net' string __file__ = '../bhoelHelper/machar.pyc' string __version__ = '1.1' float eps = 2.22044604925e-16 float epsneg = 1.11022302463e-16 int ibeta = 2 int iexp = 11 int irnd = 5 int it = 53 int machdep = -52 int maxexp = 1024 int minexp = -1022 int negep = -53 int ngrd = 0 float xmax = 1.79769313486e+308 float xmin = 2.22507385851e-308
Function to determine machine-specific parameters affecting floating-point arithmetic.
This is build after "NUMERICAL RECIPES in C", second edition, Reprinted 1996, pp. 889.
ibeta
it
machep
ibeta
that, added to 1.0 gives something different
from 1.0.
eps
ibeta'**'machdep
, loosly
referred to as the 'floating-point precision.'
negep
ibeta
that,
subtracted from 1.0, gives something different from 1.0.
epsneg
ibeta'**'negep
, another way of defining
floating-point precision. Not infrequently epsneg
is
0.5 times eps
; occasionally eps
and epsneg
are
equal.
iexp
minexp
ibeta
consistent with there no leading zeros in the mantissa.
xmin
ibeta'**'minexp
, generally
the smallest (in magnitude) usable floating value
maxexp
ibeta
that causes
overflow.
xmax
irnd
irnd
returns 2 or 5, then your computer is
compilant with the IEEE standard for rounding. If it
returns 1 or 4, then it is doing some kind of rounding,
but not the IEEE standard. If irnd
returns 0 or 3,
then it is truncating the result, not rounding it.
ngrd
-- Is the number of 'guard digits'
used when truncating
the ploduct of two mantissas to fit the representationThis is taken from "NUMERICAL RECIPES in C", second edition,
Reprinted 1996.