Auto unit scaling in applets after upgrading to ARTIQ 7

jfniedermeyer

Hi everyone. We recently upgraded to ARTIQ 7 and found that applets were no longer scaling units automatically. This means if I have an experiment that scans time on the x-axis from 0 to 1 ms, the tick labels will go out to 1, but the unit of the plot will read just "s", which means using plots for manual calibration can get confusing. In other words, the numerical scaling works fine, but the unit scaling is broken.

After trying a bunch of workarounds, the only thing we could find to fix this behavior was downgrading the PyQtGraph package from 0.12.3 to 0.11.0 (the latter was used in ARTIQ 6). In fact, it starts breaking in 0.11.1.

It doesn't strictly seem to be a PyQtGraph problem, because if I generate a plot in my ARTIQ Conda environment, it scales fine. It seems something changed in PyQtGraph between 0.11.0 and 0.11.1 such that the way ARTIQ interfaces with it no longer works.

With all of this said, has anyone found any way to get PyQtGraph 0.12.3 to work with unit scaling (other than hard coding units)?

wlph17

Hi, may I ask for more details about the applets you mantion? Because I don't think those applets we provided have units label. And I cannot reproduce your problem, it works fine for me if I add the label on the axis.

jfniedermeyer

Hi! Yes, if one edits a simple plot widget to include units using standard PyQtGraph up until this latest version would autoscale SI units, meaning it would apply G, M, m, µ, n, etc. to whatever you fed in as units to the axes objects. This option is enabled by default in PyQtGraph. This is useful for us because we will do the same experiment scanning over different orders of magnitudes so it helps keep things easy to read and quickly interpret. I can post an example of such a plot widget later this morning.

jfniedermeyer

@wlph17 , here is an example of one of the Applets we've used that's worked as expected from ARTIQ 3 through 6: https://pages.nist.gov/artiq_scan_framework/_modules/scan_framework/applets/plot_xy.html#SimpleApplet

wlph17

I see. I read your Applets, maybe it has something to do with "x_axis.enableAutoSIPrefix(False)". I set this to True and it worked.

jfniedermeyer

Thanks! Unfortunately, that method isn't called in the version of the applet I'm using and it is set to True by default in PyQtGraph (it's a new addition by a colleague developing that ARTIQ extension), but it is good to know that it works for you. I'll give it a shot again and see if it works. Perhaps it is an issue with another module in my environment.

jfniedermeyer

Thanks for your help. It seems it's a problem with our implementation of this applet code using deprecated functionality (though we aren't sure exactly where the issue is yet) rather than a problem with PyQtGraph 0.12.3. Rebuilding using the updated applet works without issue.

wlph17

Glad to hear that, you're welcome, happy I could be of help.