[Numpy-discussion] Re: Using Reduce with Multi-dimensional Masked array
Sue Giller
sag at hydrosphere.com
Thu Nov 29 15:21:04 CST 2001
Paul,
Well, you're right. I did misunderstand your reply, as well as what
the various functions were supposed to do. I was mis-using the
sum, minimum, maximum as tho they were MA.<op>.reduce, and
my test case didn't point out the difference. I should always have
been doing the .reduce version.
I apologize for this!
I found a section on page 45 of the Numerical Python text (PDF
form, July 13, 2001) that defines sum as
'The sum function is a synonym for the reduce method of the add
ufunc. It returns the sum of all the elements in the sequence given
along the specified axis (first axis by default).'
This is where I would expect to see a caveat about it not retaining
any mask-edness.
I was misussing the MA.minimum and MA.maximum as tho they
were .reduce version. My bad.
The MA.average does produce a masked array, but it has changed
the 'missing value' to fill_value=[ 1.00000002e+020,]). I do find this
a bit odd, since the other reductions didn't change the fill value.
Anyway, I can now get the stats I want in a format I want, and I
understand better the various functions for array/masked array.
Thanks for the comments/input.
sue
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