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Matlab: large lag when sending stimulation codes

Posted: Thu Apr 04, 2019 2:04 pm
by Nico A.
Hi, I am using a Matlab box to send stimulations, but there is a large gap between the Event and the time point when the stimulation is sent (approx. 200 ms). Is this normal?

I read in the following site that some lag is to be expected with stimulations via the Matlab Scripting box:
http://openvibe.inria.fr/overview-sendi ... -openvibe/

However, 200 ms seems like a lot. I also could not solve the problem with lowering the box clock frequency.

Re: Matlab: large lag when sending stimulation codes

Posted: Mon Apr 08, 2019 8:00 am
by Thibaut
Matlab is a heavy language, not really done for optimization and real time. Python would be "maybe" faster.

Re: Matlab: large lag when sending stimulation codes

Posted: Thu Apr 11, 2019 6:42 am
by Nico A.
Thank you for the answer!
Right now I'm trying the figure out how the "external processing" box works; are there example Scenarios with external processing boxes that call a script rather than an executable? I always receive the error "No Client connected before the timeout."

edit: another question: why is there no Python Scripting box in my Version of OpenVibe Designer 2.2.0? Is it maybe because it has become obsolete and is replaced by the External Processing box?

Re: Matlab: large lag when sending stimulation codes

Posted: Thu Apr 11, 2019 7:50 am
by Thibaut
It's weird for the python box, it is always present normally, you miss other boxes?

Re: Matlab: large lag when sending stimulation codes

Posted: Thu Apr 11, 2019 8:40 am
by Nico A.
The Matlab Scripting box is there. In the Folder "Scripting" there are the following boxes:

DLL Bridge
External Processing
Lua Stimulator
Matlab Scripting

When I type "python" in the search field (boxes) I get no results.

Re: Matlab: large lag when sending stimulation codes

Posted: Thu Apr 11, 2019 9:14 am
by Thibaut
Have you the correct python install (2.7 & 3.4 x64 if your openvibe is compile in 64 x32 if your openvibe is compile in 32)

Re: Matlab: large lag when sending stimulation codes

Posted: Fri Apr 12, 2019 10:18 am
by Nico A.
I tried installing Python 3.4.4 64 bit and reinstalled OpenVibe 64 bit. But there is still no Python Scripting box :(

Re: Matlab: large lag when sending stimulation codes

Posted: Mon Apr 15, 2019 8:51 am
by Thibaut
Hi,
When you launch OpenViBE what is the log on the console wndows (the black windows) ?
Thibaut