[SciPy-User] -inf when summing arrays

Kytt MacManus kmacmanu@ciesin.columbia....
Mon Sep 19 09:57:30 CDT 2011

Hello and good day,

I am a newbie to the numpy/scipy so I apologize if this is a trivial 

I have been attempting to do a simple zonal sum of 2 arrays.  I have one 
integer array of zones (labels), and another array of floating point values.

For some reason when I attempt 

The return value is -inf for each of my zones.

If I run valueArray.sum() an actual number is returned.

I am not sure what the -inf signifies and have not been able to locate 
any useful documentation on the subject.

Any insight or advice would be much appreciated.


Kytt MacManus
Geographic Information Specialist
Earth Institute
Columbia University

Adjunct Lecturer
School of International and Public Affairs
Columbia University

P.O. Box 1000
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