[Numpy-discussion] numarray: need Float32 abs from array of type na.Complex64 or na.Complex32

Sebastian Haase haase at msg.ucsf.edu
Wed Mar 1 18:14:02 CST 2006


Hi,
I just was hunting a very strange bug: I got weird results .... anyway.

I found that I was using this line of code:
if img.type() in (na.Complex64, na.Complex32):
     img = abs(na.asarray(img, na.Float32))

Now I don't understand how this code worked at all ? But I only saw those 
"weird results" after looking at the "dimmest corners" in my image and 
otherwise all images looked O.K.

The goal here was to get a single precision absolute for either a complex64 or 
complex32 valued image array WITHOUT creating a temporary array.
My thinking was that:
img = na.abs( na.asarray(img, na.Complex32) ) 
would create a complete temporary version of img starts out being Complex64
Is this really the case ?

Thanks for any hints,
Sebastian Haase




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