[SciPy-user] logexpdot

Brian Lewis brian.lewis17@gmail....
Mon Jun 15 17:21:59 CDT 2009

```Hi all,

This is my first foray into np.newaxis.  I needed a dot product for
logarithm arrays and since I am always working with matrices, I just did
2D.  I'm looking for comments and suggestions for what I've implemented.
Also, is it easy to generalize this beyond 2D?

import numpy as np

def logdotexp2__1(x,y, out=None):
# horrible
r,c = x.shape[0], y.shape[1]
if out is None:
out = np.empty((r,c))
for i in xrange(r):
for j in xrange(c):
return out

def logdotexp2__2(x,y, out=None):
# less horrible
r,c = x.shape[0], y.shape[1]
if out is None:
out = np.empty((r,c))
for i in xrange(r):
return out

def logdotexp2__3(x,y, out=None):
# good?
r,c = x.shape[0], y.shape[1]
if out is None:
out = np.empty((r,c))
out=out)
return out

if __name__ == '__main__':
k = 10
a = np.arange(k**2).reshape((k,k))
b = np.arange(k**2,2*k**2).reshape((k,k))
#    timeit logdotexp2__1(a,b)
#    timeit logdotexp2__2(a,b)
#    timeit logdotexp2__3(a,b)

Thanks.
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