OpenGL different time-consuming for different Matlab versions

Hello, Matlab experts: I have a problem, recently, I run my matlab code, it is just to use surfstat package to render some result pictures(8 images), for example for this function, SurfStatT, it will take different time-consuming in different matlab version and different openGL executing method(hardware or software), and I found a strange result:

For my OS, linux ubuntu 14.04! In my computer, I have matlab2011b and matlab2016a!

1) Obviously, when I run it with openGL hardware, it will be much faster than the software way!

2) This time, I run both round with openGL hardware, and I run it with diff matlab version, !!!! with Matlab2011b, it just took me 65 s, on contrast, with Matlab2016a, which I thought should be faster, it took me 250s, 4 times more than Matlab2011b, with the two round, they use the same graphics card on the same computer!

I attach the matlab log file, any help would be appreciated:) Look forward to your reply!!! Good day

Answer 1

[Walter Roberson]

R2014b and later use different rendering algorithms that provide more flexibility. For some kinds of graphics the new algorithms are faster; for some kinds of graphics the new algorithms are slower. There are only a few things for which it is known to be much slower. (One of the things known to be much slower at times is converting complex surfaces to PDF.)

So, yes, slower for R2016a is a distinct possibility (but not a certainty.)

I am not familiar with how SurfStat http://www.math.mcgill.ca/keith/surfstat/ does its rendering.

[Junhao WEN]

Thank you for your rapid response, so what you mean is that after Matlab 2014, they have changed the openGL algorithms, it is more flexible but basically more slowly? Yes, in my code, my output are 8 jpg images, but before when I save it as pdf, it seemed to be much slower!

[Walter Roberson]

The parts of OpenGL they call has changed. For example there is now support for anti-aliasing, and unicode characters are now permitted in graphics, and the ways that axes labels can be formatted is improved.

Parts of it are faster; parts of it are not. See http://blogs.mathworks.com/graphics/2015/06/09/object-creation-performance/

I never recommend JPEG format; it messes up colors and sharp edges.

Saving to PDF can be much slower now. Mathworks decomposes the graphics into much smaller polygons than before, in an attempt to work around bugs in common PDF renderers and increase the accuracy of the plotting. Unfortunately there are other common PDF renderers that have bugs for graphics that are divided that finely. R2016a performance for PDF is improved over R2015b but is not great. And there are font difficulties now :(

Answer 2

[Junhao WEN]

here is the log file:

I think this is bacause of the openGL, so any openGL expert????