Re: [Matplotlib-users] Accelerating PDF saved plots

[Benjamin R. <ben...@ou...>]

On Thu, Jul 5, 2012 at 1:55 PM, Gökhan Sever <gok...@gm...> wrote:

> And you might get back more memory if you didn't have to have all the data
>> in memory at once, but that may or may not help you.  The only other
>> suggestion I can make is to attempt to eliminate the overhead in the inner
>> loop.  Essentially, I would try making a single figure and a single
>> AxesGrid object (before the outer loop).  Then go over each subplot in the
>> AxesGrid object and set the limits, the log scale, the ticks and the tick
>> locater (I wouldn't be surprised if that is eating up cpu cycles).  All of
>> this would be done once before the loop you have right now.  Then create
>> the PdfPages object, and loop over all of the plots you have, essentially
>> recycling the figure and AxesGrid object.
>>
>> At end of the outer loop, instead of closing the figure, you should call
>> "remove()" for each plot element you made.  Essentially, as you loop over
>> the inner loop, save the output of the plot() call to a list, and then when
>> done with those plots, pop each element of that list and call "remove()" to
>> take it out of the subplot.  This will let the subplot axes retain the
>> properties you set earlier.
>>
>> I hope that made sense.
>> Ben Root
>>
>>
> Hi Ben,
>
> I should have data the available at once, as I directly read that array
> from a netcdf file. The memory requirement for my data is small comparing
> to overhead added once plot creation is started. Fabrice's reply includes
> most of what you describe except the remove call part. These changes made
> big impact to lower my execution times. Thank you again for your
> explanation.
>
>
> --
> Gökhan
>

Actually, looking at Fabrice's code, you might be able to get it to be
slightly faster.  Lines 39-41 should be protected by a "if i == 0"
statement because it only needs to be done once.  Furthermore, you might
get some more improvements if you allow the subplots to share_all, in which
case, you only need to set the limits and maybe the scale and the locator
once.

Cheers!
Ben Root