[Numpy-tickets] [NumPy] #445: normed histogram returns incorrect results
NumPy
numpy-tickets@scipy....
Mon Feb 5 14:30:28 CST 2007
#445: normed histogram returns incorrect results
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Reporter: cvwright | Owner: somebody
Type: defect | Status: new
Priority: normal | Milestone:
Component: numpy.lib | Version: devel
Severity: normal | Keywords:
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The histogram() function, when called with normed=True, returns incorrect
results for the bins' frequencies. The frequencies should sum to 1.0 in
order to be a real probability distribution, but usually with the current
code they do not.
Looking at the current version of the code in trac, I believe the problem
is on lines 105 and 106 of function_base.py. On line 105, we calculate
the width of a bin, and on line 106, we divide the counts for each bin by
the size of the input times the bin width. I think the problem could be
fixed by simply removing the bin width calculation and instead dividing
the bin counts by only the number of samples in the input.
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Ticket URL: <http://projects.scipy.org/scipy/numpy/ticket/445>
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