On Wed, Jun 12, 2013 at 3:25 PM, Moroney, Catherine M (398D) <[email protected]> wrote: > Hello, > > I've got two arrays of the same shape that I read in from a file, and I'm > trying to > difference them. Very simple stuff, but I'm getting weird answers. > > Here is the code: > >>>> counts1 = hfile1.read_grid_field("CFbA", >>>> "TerrainReferencedRCCMFraction_Num") >>>> counts2 = hfile2.read_grid_field("CFbA", >>>> "TerrainReferencedRCCMFraction_Num") >>>> counts1.max(), counts2.max() > (13, 13) >>>> counts1.min(), counts2.min() > (0, 0) >>>> numpy.all(counts1 == counts2) > False >>>> diff = counts1 - counts2 >>>> diff.max() > 4294967295 !! WHAT IS HAPPENING HERE ?? >>>> sum = counts1 + counts2 >>>> sum.max() > 26 > > As you can see, the range of values in both arrays is 0 to 13, and the sum > behaves normally, but the difference gives this weird number. > > When I create dummy arrays, the subtraction works fine. So there must be > some funny value > lurking in either the counts1 or counts2 array, but the numpy.isnan() test > returns False. > > Any ideas for how I debug this?
check the dtype of the count variables, may be uint diff =1 * counts1 - counts2 Josef > > Catherine > > > _______________________________________________ > NumPy-Discussion mailing list > [email protected] > http://mail.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
