pcolorfast and log axes.

Greetings.

I’ve recently found that when I replace pcolor with pcolorfast, the image will not scale correctly when placed on an axis with a logarithmic scale. It will remain linear, thus not matching the axis range whatsoever. The pcolor plot will still fit nicely in the axis object, but the ticks and labels clearly do not match the data. I’ve tried several things, from changing the axis from linear to log before and after using pcolorfast, etc, but pcolorfast artist objects do not seem to respond to this. Again, pcolor acts as one would expect.

Complicating this is that I have made two changes at once: upgrading from MPL 99 to 1.0 and switching from pcolor to pcolorfast. As such, I do not know if this a new or old issue (or if it is an issue at- perhaps this behavior is on purpose.)

If anyone could shed some light on this, that would be great. Pcolorfast is preferable over pcolor because of the complexity of my plots and the speed up gained by using pcolorfast.

Thanks!

-dw

Greetings.

I've recently found that when I replace pcolor with pcolorfast, the
image will not scale correctly when placed on an axis with a logarithmic
scale. It will remain linear, thus not matching the axis range
whatsoever. The pcolor plot will still fit nicely in the axis object,
but the ticks and labels clearly do not match the data. I've tried
several things, from changing the axis from linear to log before and
after using pcolorfast, etc, but pcolorfast artist objects do not seem
to respond to this. Again, pcolor acts as one would expect.

Complicating this is that I have made two changes at once: upgrading
from MPL 99 to 1.0 and switching from pcolor to pcolorfast. As such, I
do not know if this a new or old issue (or if it is an issue at- perhaps
this behavior is on purpose.)

If anyone could shed some light on this, that would be great.
  Pcolorfast is preferable over pcolor because of the complexity of my
plots and the speed up gained by using pcolorfast.

The problem is that I never quite finished pcolorfast; it probably needs a little more refinement in argument handling, and it needs to detect nonlinear axes. The latter never even occurred to me when I wrote it, since that case does not occur in the applications for which I use it.

For now, try using pcolormesh instead of pcolorfast. It will handle log axes, and although probably not quite as fast as pcolorfast could be if it correctly handled log axes, it will be *much* faster than pcolor.

Eric

···

On 07/14/2010 06:49 AM, Daniel Welling wrote:

Thanks!
-dw

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