Re: [Visualpython-users] Does Glowscript have numpy-like performance?

[Bruce S. <Bru...@nc...>]

After more study of GlowScript vs. VPython versions of the VPython
gas.py program:

VPython gas.py with 100 atoms, dt = 1e-5, rate 500, no graphing: 100
iterations = 0.4 seconds.

If gas.py is modified to not use numpy, the time is 3.6 s.

The similar Glowsript program with same conditions: 100 iterations =
3.2 seconds on Firefox.

Oddly, on at least one 64-bit Windows machine, the time is 5.3 seconds
on Chrome.

On a 32-bit Windows laptop, 4.2 seconds on Firefox, 2.5 seconds on
Chrome, the reverse of the ordering on the other Windows machine.

There is a very major difference between Chrome and Firefox. With
Firefox, the animation periodically freezes, probably due to
JavaScript garbage collection. These freeze-ups do not occur with
Chrome or Safari.

-----------------------

You can run this program (if you have a WebGL-enabled browser; see the
Help at glowscript.org) at

http://www.glowscript.org/#/user/GlowScriptDemos/folder/Examples/program/HardSphereGas

A summary statement is that the factor of 10 speed advantage of
VPython over GlowScript comes completely from the parallel C-speed
numpy arrays. Without numpy, the VPython and GlowScript (Python and
JavaScript) execution speeds are about the same. I had mistakenly
thought that JavaScript was much faster than Python, but  that seems
not to be the case.

Bruce Sherwood