[Numpy-discussion] Iterative Matrix Multiplication

Ian Mallett geometrian at gmail.com
Fri Mar 5 17:58:52 EST 2010


Cool--this works perfectly now :-)

Unfortunately, it's actually slower :P  Most of the slowest part is in the
removing doubles section.

Some of the costliest calls:

#takes 0.04 seconds
inner = np.inner(ns, v1s - some_point)

#0.0840001106262
sum_1 = sum.reshape((len(sum), 1)).repeat(len(sum), axis = 1)

#0.0329999923706
sum_2 = sum.reshape((1, len(sum))).repeat(len(sum), axis = 0)

#0.0269999504089
comparison_sum = (sum_1 == sum_2)

#0.0909998416901
diff_1 = diff.reshape((len(diff), 1)).repeat(len(diff), axis = 1)

#0.0340001583099
diff_2 = diff.reshape((1, len(diff))).repeat(len(diff), axis = 0)

#0.0269999504089
comparison_diff = (diff_1 == diff_2)

#0.0230000019073
same_edges = comparison_sum * comparison_diff

#0.128999948502
doublet_count = same_edges.sum(axis = 0)

Ian
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