[SciPy-user] Precision error on Mac OS X (PPC)

Erin Sheldon erin.sheldon at gmail.com
Wed Nov 15 22:22:03 CST 2006


Hi Iain -

So I ran this on my powerbook G4, 10.4.8:
[~]|11> print numpy.finfo(numpy.float128).min,numpy.finfo(numpy.float128).max,numpy.finfo(numpy.float128).eps
9223372034707292160.0 -9223372034707292160.0 1.38178697010200053818e-76

Same answer you got but no errors reported.  But of
course those answers are totally wrong.

Same thing on my AMD64 machine:
In [6]: print numpy.finfo(numpy.float128).min,numpy.finfo(numpy.float128).max,
numpy.finfo(numpy.float128).eps
-1.18973149535723176502e+4932 1.18973149535723176502e+4932
1.08420217248550443401e-19

Looks better.  So there is a bug on OS X it seems.
Erin


On 11/14/06, Iain Day <iain at day-online.org.uk.invalid> wrote:
> Hi,
>
> I apologise if this is the wrong list for this. I have been having some
> precision issues with some code I've got. I've searched the list
> archives and came across these tests. SciPy and numpy are installed from
> Fink, and running on a 1.5GHz G4 with Mac os x 10.4.8.
>
>  >>> import numpy
>  >>> import scipy
>  >>> numpy.__version__
> '1.0'
>  >>> scipy.__version__
> '0.5.1'
>  >>> print numpy.finfo(numpy.float32).min
> -3.40282346639e+38
>  >>> print numpy.finfo(numpy.float32).min,
> numpy.finfo(numpy.float32).max, numpy.finfo(numpy.float32).eps
> -3.40282346639e+38 3.40282346639e+38 1.19209289551e-07
>  >>> print numpy.finfo(numpy.float64).min,
> numpy.finfo(numpy.float64).max, numpy.finfo(numpy.float64).eps
> -1.79769313486e+308 1.79769313486e+308 2.22044604925e-16
>  >>> print numpy.finfo(numpy.float128).min,
> numpy.finfo(numpy.float128).max, numpy.finfo(numpy.float128).eps
> Warning: overflow encountered in add
> Warning: invalid value encountered in subtract
> Warning: invalid value encountered in subtract
> Warning: overflow encountered in add
> Warning: invalid value encountered in subtract
> Warning: invalid value encountered in subtract
> 9223372034707292160.0 -9223372034707292160.0 1.38178697010200053818e-76
>
> Any thoughts?
>
> Iain
>
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