[Numpy-discussion] buggy buggy bugyy: format and casting ?

Robert Kern robert.kern at gmail.com
Fri Sep 15 14:07:25 CDT 2006

Eric Emsellem wrote:
> Hi,
> I am facing a rather frustrating problem with numpy/scipy: after
> upgrading to svn numpy and scipy, and trying to remove most of the now
> unnecessary casting (floats) the program I wrote does not give me the
> right answer. It seems that the answer is somewhat scaled down (but not
> in a simple way). I had this kind of behaviour some time ago when scipy
> and numpy were not fully compatible and then I had to cast the floats
> explicitely in my program to make it work. But now it SHOULD be fully
> compatible as far as I understand the issue. So my question is:
> is there any remaining flaws in terms of casts/format between scipy and
> numpy? I am specifically using the scipy functions:
> - special.erf, special.erfc, orthogonal.ps_roots, integrate.quad...
> and the numpy functions : sum, sqrt, exp, sin, cos, arctan.
> I am doing all the calculations using numpy.float32.

Could you give us a short piece of code that demonstrates the problem? You don't 
state what flaws you were working around before. Note that some of those 
functions in scipy are unavoidably implemented in double precision at the 
C/FORTRAN level.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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