I think you are using the masked array and/or the np.where incorrectly.
ratio = np.where(A >= B, A/B, B/A)
ratio = np.ma.masked_array(ratio, mask=(~np.isfinite(ratio)))
And then do a contourf on ratio.
Ben Root
···
On Tue, Feb 1, 2011 at 1:48 PM, Jeremy Conlin <jlconlin@…287…> wrote:
On Tue, Feb 1, 2011 at 11:22 AM, Benjamin Root <ben.root@…1304…> wrote:
On Tue, Feb 1, 2011 at 11:58 AM, Jeremy Conlin <jlconlin@…287…> wrote:
I have two arrays and I want to plot the ratio of A/B when A>=B or B/A
when A<B. I can create numpy masked arrays to find the result in
these two instances, but I’m having trouble plotting them. Below I
have a minimal example. I get a plot, but only from the second time I
issue the pcolormesh command. Is there a way to combine the two
arrays for plotting or to plot without overlapping?
Thanks,
Jeremy
Try this:
ratio = numpy.where(A >= B, A/B, B/A)
Figure = pyplot.figure()
pyplot.pcolormesh(ratio)
I hope that helps!
numpy.where helps a lot. To further complicate things, some elements
of A or B are zero which causes A/B or B/A to be infinite in some
places. I can use numpy.where or create a masked array to elimnate
those elements that are infinite, but then my plotted values are
either 0 or 1 (False or True); I lose all the interesting data. The
documents of pcolormesh show that I can pass a masked_array, but I’m
successful in doing that. Do you have another trick you can show to
help me get around this problem?
Thanks again,
Jeremy
Yeah, that seems to work. Thanks for the help.
Jeremy
···
On Tue, Feb 1, 2011 at 1:11 PM, Benjamin Root <ben.root@...1304...> wrote:
On Tue, Feb 1, 2011 at 1:48 PM, Jeremy Conlin <jlconlin@...287...> wrote:
On Tue, Feb 1, 2011 at 11:22 AM, Benjamin Root <ben.root@...1304...> wrote:
>
>
> On Tue, Feb 1, 2011 at 11:58 AM, Jeremy Conlin <jlconlin@...287...> >> > wrote:
>>
>> I have two arrays and I want to plot the ratio of A/B when A>=B or B/A
>> when A<B. I can create numpy masked arrays to find the result in
>> these two instances, but I'm having trouble plotting them. Below I
>> have a minimal example. I get a plot, but only from the second time I
>> issue the pcolormesh command. Is there a way to combine the two
>> arrays for plotting or to plot without overlapping?
>>
>> Thanks,
>> Jeremy
>>
>>
>
> Try this:
>
> ratio = numpy.where(A >= B, A/B, B/A)
> Figure = pyplot.figure()
> pyplot.pcolormesh(ratio)
>
> I hope that helps!
numpy.where helps a lot. To further complicate things, some elements
of A or B are zero which causes A/B or B/A to be infinite in some
places. I can use numpy.where or create a masked array to elimnate
those elements that are infinite, but then my plotted values are
either 0 or 1 (False or True); I lose all the interesting data. The
documents of pcolormesh show that I can pass a masked_array, but I'm
successful in doing that. Do you have another trick you can show to
help me get around this problem?
Thanks again,
Jeremy
I think you are using the masked array and/or the np.where incorrectly.
ratio = np.where(A >= B, A/B, B/A)
ratio = np.ma.masked_array(ratio, mask=(~np.isfinite(ratio)))
And then do a contourf on ratio.