[Numpy-discussion] buggy buggy bugyy: format and casting ==> BUG in numpy.sum?

Eric Emsellem emsellem at obs.univ-lyon1.fr
Mon Sep 18 04:55:58 CDT 2006


Hi again

after some hours of debugging I finally (I think) found the problem:

numpy.sum([[0,1,2],[2,3,4]])
24

numpy.sum([[0,1,2],[2,3,4]],axis=0)
array([2, 4, 6])

numpy.sum([[0,1,2],[2,3,4]],axis=1)
array([3, 9])


Isn't the first line supposed to act as with "axis=0" by default (see
help numpy.sum!)...???
Not setting axis=0 it sums everything!

Is that the expected behaviour or is the doc not updated? (I realise it
may be better to force axis=.. to indicate what you need but still.. the
example in numpy.sum help gives:
sum([[0, 1], [0, 5]])
    array([0, 6]) which is not what it gives when you do it...)

thanks

Eric




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