[SciPy-user] help with precision for big numbers
Johann Cohen-Tanugi
cohen at slac.stanford.edu
Tue May 13 04:40:31 EDT 2008
Hello,
I am computing :
In [22]: for i in range(6):
s=(1.+Toff/Ton)**i*sp.factorial(Non+Noff-i)/sp.factorial(Non-i)
print "%.14g"%s
....:
....:
4.3585218122217e+42
9.7493251062853e+42
1.7917678573714e+43
2.5383377979428e+43
2.4658138608587e+43
1.2329069304293e+43
A colleague using GSL and C code with double precision and long double (
I am not sure whether he has a 64bit machine) obtained the following
values :
4.3585218122216e+42
1.0131651581042e+43
1.9350541758386e+43
2.8488297588735e+43
2.8759614708627e+43
1.4943721368208e+43
Close but not identical...... I was wondering if there is a way to
increase numerical accuracy within scipy, assuming the standard behavior
is not optimal with this respect. Or any other thoughts about these
discrepancies? Or some nifty tricks to recover lost precision by
organizing the computation differently?
thanks in advance,
Johann
More information about the SciPy-User
mailing list