float64 print digits

Ulrich Dorda ulrich.dorda at cern.ch
Fri Mar 2 11:35:50 CET 2007


I need a pytho nscript to read numbers(with loads of digits) from a 
file, do some basic math on it and write the result out to another file.

My problem: I don't get python to use more digits:

In order to try this I type:

The normal precision one:
 >>> from numpy import *
 >>> x=1.23456789123456789123456789
 >>> print "%35.25e" %x
    1.2345678912345679000000000e+000


    Now I try to use float64 to get more digits

 >>> z=zeros(3,float64)
 >>> z[0]
0.0
 >>> type(z[0])
<type 'numpy.float64'>
 >>> z[0]=1.23456789123456789123456789
 >>> type(z[0])
<type 'numpy.float64'>
 >>> print "%35.25e" %z[0]
    1.2345678912345679000000000e+000

This cuts the digits just like the 32bit case.

Can anyone please help me get more digits?

Thank you very much in advance,

Ulrich





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