BLACS issue: python "has stopped working" on showing GUI

[Matt Aldous]

Hello all,

I am having an issue with labscript on a Windows 7 machine, installed using Anaconda (conda install -c labscript-suite labscript-suite). As far as I can tell, every part of the suite is behaving as normal, except for BLACS, which gets as far as "showing GUI" and then python crashes, throwing a windows "Python has stopped working" window.

BLACS was working fine a few months ago (the last time I tested it) and the only thing I can think of that might have changed in the meantime is installing pyqt5 on the machine to run a separate python script. Could this have caused the issue? I would have thought Conda would have selected the correct version via the dependency tree if so. I have tried uninstalling and reinstalling labscript but this did not fix it.

Are there some log files somewhere I should look at?

Kind regards,

Matthew

[Chris Billington]

Hi Matthew,

This sounds like it might be a long-standing issue that occurs rarely enough that we haven't been able to reproduce it reliably in order to fix it:

https://github.com/labscript-suite/labscript-utils/issues/27

The problem is the saved geometry of the tabs - there's a calculation of how big some widgets should be, and in some unlucky configurations this triggers something else to change size and the whole thing repeats without converging until there's a stack overflow.

If it's what I think it is, then the installation of PyQt in a different Python environment should not be relevant and would just be a coincidence. You're right that it shouldn't matter to conda whether PyQt5 is installed elsewhere, nonetheless there are remarkably many ways to get broken Python setups on Windows and it would not surprise me at all to see interference between these supposedly separate environments. But in this case, the fact that the other programs work OK and it's just BLACS crashing makes me think it's the issue I'm thinking of, which is specific to BLACS.

So firstly, I'll ask if you could send us some files (if you don't mind sharing - you can send it to me privately at chrisjbi...@gmail.com if you don't want to share it publicly) so that we might be able to use your current state to reproduce the issue. If we can reproduce it reliably, then we'll almost certainly be able to fix it.

Then I'll let you know the workaround that will hopefully fix the problem for you.

So the files we would need to reproduce the issue are your connection table h5 file, your connection table .py file, your labconfig file, and the BLACS settings file. In a default setup these would be (replace example_apparatus with apparatus name or C:\ with shared-drive letter/path as appropriate):

• labconfig file: <user-home>\labscript-suite\labconfig\<hostname>.ini
• BLACS settings file: <user-home>\labscript-suite\app_saved_configs\example_apparatus\blacs\<hostname>.h5
• connection table .py file: <user-home>\labscript-suite\userlib\labscriptlib\example_apparatus\connection_table.py
• connection table .h5 file: C:\Experiments\example_apparatus\connection_table.h5

Also, what resolution is the screen, how many screens do you have, and if multiple, how are they laid out?

The workaround is:

• Delete the BLACS settings file: e.g. <user-home>\labscript-suite\app_saved_configs\example_apparatus\blacs\<hostname>.h5

(don't delete it before sending it to us, please :) )

BLACS will then forget its front panel settings and tab layout, which is a bit of a pain. If this is important not to lose, let me know and I'll see what I can do to extract the non-geometry-related settings from the existing BLACS settings file into a new one.

Regards,

-Chris

--
You received this message because you are subscribed to the Google Groups "the labscript suite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to labscriptsuit...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/labscriptsuite/6d9eb506-acfc-4c54-8f22-82ffe800a67bo%40googlegroups.com.