[Numpy-discussion] problem with poisson generators

Flavio Coelho fccoelho at gmail.com
Tue Jul 12 13:34:21 EDT 2005


I am having problems with the poisson random number generators of both 
Numarray and Numeric.
I can't replicate it when calling the function from the python cosonle, but 
it has consistently malfunctioned when used within one of my scripts.

What happens is that it frequently return a value greater than zero when 
called with zero mean: poisson(0.0)

Unfortunately My program is too big to send attached but I have confirmed 
the malfunction by printing both the mean and the result whenever it spits 
out a wrong result.

This is very weird indeed, I have run poisson millions of times by itsel on 
the python console, without any problems...

I hope it is some stupid mistake, but when I replace the poisson function 
call within my program by the R equivalent command (rpois) via the rpy 
wrapper, everything works just fine... 

any Ideas?

Flávio Codeço Coelho
registered Linux user # 386432
Great spirits have always found violent opposition from mediocrities. The
latter cannot understand it when a man does not thoughtlessly submit to
hereditary prejudices but honestly and courageously uses his intelligence.
Albert Einstein
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