[Scipy-tickets] [SciPy] #1398: problem with numpy 0's in stats.poisson.rvs
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Sat Apr 9 01:29:21 CDT 2011
#1398: problem with numpy 0's in stats.poisson.rvs
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Reporter: parejkoj | Owner: somebody
Type: defect | Status: new
Priority: normal | Milestone:
Component: scipy.stats | Version: 0.8.0
Keywords: |
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Changes (by schwarz):
* cc: schwarz (added)
Comment:
I would like to describe a case, where I need a poisson with mu=0:
Often, I have to create simulated observations of astronomical sources. In
that process, I assume a shaped source in a 2d array (source_image). This
source has values >0 in its pixels. Outside the source, the image has
pixel values = 0 (Because no photons should come from that regions).
The observation is then simple to simulate:
{{{
obs = poisson.rvs(source_image)
}}}
But since the biggest part of the image is =0, I get "Domain errors". SO:
currently I'm doing
{{{
obs = poisson.rvs(source_image + 0.000001)
}}}
While this helps, it is certainly wrong in a scientific way and I would
prefer to use the true values.
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Ticket URL: <http://projects.scipy.org/scipy/ticket/1398#comment:4>
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