bugGNU Octave - Bugs: bug #53845, Octave too slow when plotting...


bug #53845: Octave too slow when plotting large arrays with QT graphics toolkit

Submitted by:  None
Submitted on:  Sun 06 May 2018 02:07:04 AM UTC  
Category:  Plotting Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Performance
Status:  None Assigned to:  None
Originator Name:  Alex Originator Email:  -email is unavailable-
Open/Closed:  Open Release:  4.4.0
Operating System:  Microsoft Windows

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Mon 07 May 2018 04:55:56 PM UTC, comment #3:

That is great! I had noticed a performance decrease, but hadn't gotten around to trying a general direct performance comparison. This work around makes a dramatic, immediate difference!

Marshall <marsian>
Mon 07 May 2018 12:08:11 AM UTC, comment #2:

Fantastic! Its solution is as simple as efficient. Many thanks Markus.

Sun 06 May 2018 11:52:41 AM UTC, comment #1:

Octave 4.4.0 for Windows uses software rendering by default via a opengl32.dll shipped with Octave. Earlier versions used the system's opengl32.dll which turned out to be unreliable with graphics cards drivers from many different vendors.

You could try re-naming opengl32.dll that you find in the "bin" directory where Octave is installed. That should make Octave pick up the system's opengl32.dll (as previous versions did).
Does that make any difference with respect to performance? (It does for me.)

Markus M├╝tzel <mmuetzel>
Project Member
Sun 06 May 2018 02:07:04 AM UTC, original submission:

Octave 4.2.2 and 4.4.0, Win32 or Win64, with standard installation from ZIP file, in Windows 10, running QT graphics toolkit, gets very slow when plotting large arrays. Just start the Octave gui and type plot(1:10^6); plot(10^6:-1:1). The Octave becomes very slow, almost freezing, and sometimes, by shifting the focus from the figure to the command window, it does not respond. The same does not happen when Octave 4.2.1 is running on the same computer or when the Gnuplot is set as the graphics toolkit.



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  • -email is unavailable- added by marsian (Posted a comment)
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