PTB for GNU Octave in Ubuntu 22.04

hello, I want some help. I am new to PTB. Recently, installed ubuntu 22.04, then gnu octave 6.4.0 (configured for x86_64-pc-linux-gnu) from ubuntu software repository. after that tried to installed ptb-3 from neurodebian website,as suggested in PTB website; through following and typing the given commands given there. its been more than 5 hrs, still in terminal something is setting up… and i am unable to find PTB-3 anywhere in my laptop.
Please help.

you need to provide more info, what exact commands did you execute and what output did you get on the console?

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For installation, I visited PTB website there I got the link for neurodebian website. In the second place (neurodebian website), recommended commands were “wget -O- | sudo tee /etc/apt/sources.list.d/neurodebian.sources.list
sudo apt-key adv --recv-keys --keyserver hkps:// 0xA5D32F012649A5A9” for adding neurodebian repository to my native package management system.
Then i executed “sudo apt-get update” for updating the packages.
In last the command, “sudo apt-get install octave-psychtoolbox-3” was executed for installing the PTB-3.
Now, I am waiting for getting PTB-3 anywhere in my laptop.

while visiting neurodebian for PTB-3, I found nothing for ubuntu 22.04, instead packages was only available for upto ubuntu 21.10.

Yes, Ubuntu 22.04, being a rather new release only 2 weeks old, isn’t yet supported by NeuroDebian afaik. I assume support will be added soon’ish (days to weeks - whenever Yaroslav finds the time), then with the latest PTB

In the meantime, the “universe” (or was it “multiverse”?) repo of Ubuntu 22.04 contains PTB, so if that is enabled in package sources, you can sudo apt install octave-psychtoolbox-3 to get that slightly older version from Ubuntu 22.04 itself.

Or you can use the DownloadPsychtoolbox method to get the latest current PTB from us.

Make sure to login into a GUI session that is X11/Xorg based, not Wayland based, or you will end with the Wayland nightmare, cfe. Screen('OpenWindow') and PsychImaging('OpenWindow') produce black screen - #6 by mariokleiner


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Hey Mario, thanks. I enabled the multi & universe repositories, then gave the command, “sudo apt install octave-psychtoolbox-3” and in return i got this,
"atul@atul-HP-Pavilion-Laptop-14-dv1xxx:~$ sudo apt install octave-psychtoolbox-3
[sudo] password for atul:
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
octave-psychtoolbox-3 is already the newest version (
0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.

I am still unable to access psychtoolbox-3, please help me out.

As you suggested, I can download the PTB latest version from you, using " DownloadPsychtoolbox". What is your address??

Use google or look at

Seems it is already installed. You just start octave, and then its commands should be available, e.g., PsychtoolboxRoot or PsychtoolboxVersion or a demo like LinesDemo. The first setup step would be running PsychLinuxConfiguration to optimize your laptop for neuroscience use – Admin password required.
E.g., in a terminal octave then in octave PsychLinuxConfiguration.
Or octave --gui or the Octave icon for the full Octave GUI application.


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Thanks Mario,
Commands of PsychtoolboxVersion and PsychtoolboxRoot are working and popping answers properly. Entry of command line Linesdemo leaving me to a blank, non-functional page. And, I am still unable to see/find the Psychtoolbox Homepage, like and a homepage of any application, so that i can access the library, tool, settings, etc. Please help me out.

I do not understand what you are saying, but some guessing:
PTB doesn’t have a settings page where you can click and change stuff.

What is the error you get when you run LinesDemo? Please post the full
command line output

From previous advice, citing myself:

Make sure to login into a GUI session that is X11/Xorg based, not Wayland based, or you will end with the Wayland nightmare of just blank black screens and a hang, cfe. Screen(‘OpenWindow’) and PsychImaging(‘OpenWindow’) produce black screen - #6 by mariokleiner

Currently you seem to have v3.0.18.4 from Ubuntu itself, and that version lacks automatic Wayland detection and troubleshooting for this problem → Don’t use Wayland, use a Xorg/X11 GUI session. This should make visual stimulation working.

Yesterday I got feedback from Yaroslav Halchenko of team NeuroDebian that they currently can’t provide updated packages via NeuroDebian for Ubuntu 22.04-LTS due to some technical problems. That’s a pity as i want people to upgrade to Ubuntu 22.04-LTS, it has substantial improvements for neuroscience applications, and NeuroDebian would be the most convenient method for that. But it is what it is…

Therefore, for the time being, it would be best if you’d use the DownloadPsychtoolbox method as described on our website under “Subversion-based installation”, to get the latest release, and then UpdatePsychtoolbox as needed, iow. the same procedure as when using MS-Windows or macOS.

EDIT: Yaroslav found a solution, and I’m pleased to report that the latest PTB is now available from NeuroDebian for Ubuntu 22.04-LTS. There won’t be any support for the outdated Ubuntu 21.10 though, as that reaches end of life in 2 months anyway, so no point in providing packages for it.


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ohh Thanks Mario, now I changed to X11 and then typed LinesDemo in octave’s command window, and watched a miracle of colorful lines in great motion. Thanks a lot
now for next how to find experiment/program library…? where i can find some already developed experiments. Please suggest me

Thanks dcnieho, now I typed LinesDemo and watched an animation then found this on my octave’s command window :

PTB-INFO: This is Psychtoolbox-3 for GNU/Linux X11, under GNU/Octave 64-Bit (Version 3.0.17 - Build date: Feb 22 2021).
PTB-INFO: OS support status: Linux 5.13.0-40-generic Supported.
PTB-INFO: Type ‘PsychtoolboxVersion’ for more detailed version information.
PTB-INFO: Most parts of the Psychtoolbox distribution are licensed to you under terms of the MIT License, with
PTB-INFO: some restrictions. See file ‘License.txt’ in the Psychtoolbox root folder for the exact licensing conditions.

PTB-INFO: For information about paid priority support, community membership and commercial services, please type
PTB-INFO: ‘PsychPaidSupportAndServices’.

PTB-INFO: Failed to enable realtime-scheduling [Operation not permitted]!
PTB-INFO: You need to run the script PsychLinuxConfiguration once, then logout and login again for this to work.

PTB-INFO: OpenGL-Renderer is Intel :: Mesa Intel(R) Xe Graphics (TGL GT2) :: 4.6 (Compatibility Profile) Mesa 21.2.2
PTB-INFO: VBL startline = 1080 , VBL Endline = -1
PTB-INFO: Will try to use OS-Builtin OpenML sync control support for accurate Flip timestamping.
PTB-INFO: Measured monitor refresh interval from VBLsync = 16.668200 ms [59.994479 Hz]. (50 valid samples taken, stddev=0.005448 ms.)
PTB-INFO: Reported monitor refresh interval from operating system = 16.666111 ms [60.001999 Hz].
PTB-INFO: Small deviations between reported values are normal and no reason to worry.
minsmooth = 1
maxsmooth = 7.3750

now next i want to have a introductory tour to my Psychtoolbox on my laptop. I Want to see some already developed experiments, then to do some tiny then successively large manipulations in those experiments. please suggest me the paths and tricks.

That’s not running on Ubuntu 22.04, but something older like 21.10? I’d recommend upgrading to the latest. Also an old 3.0.17 PTB…

Wrt. further steps: help Psychtoolbox gives you pointers.

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sorry, i should have told to earlier. now i am on ubuntu 21.10, and PTB 3.0.17.

…and help Psychtoolbox gave me this:

help Paychtoolbox
error: help: ‘Paychtoolbox’ not found

help Psychtoolbox
error: help: ‘Psychtoolbox’ not found

error: ‘help_Psychtoolbox’ undefined near line 1, column 1

Not sure what you did to make that happen (install in a folder with non-standard name?), but in the root folder of psyschtoolbox, there is a file Contents.m. Read the text in that file

Right, I forgot that NeuroDebian and the Linux distributions install into the root folder “psychtoolbox-3” instead of “Psychtoolbox”, so one needs to use help psychtoolbox-3 instead. Or look at the online version for the latest PTB version:

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Thank a lot. Now I can access to Contents.m and help Psychtoolbox-3. Reading the folders…