Help to debug PyCall plotting problem

General Usage
1

Hi,

first time using PyCall and I’m having problems generating plots with the Python package that I’m trying to use, but I’m not sure how to debug it.

The Python package I want to use is called ChiantiPy (GitHub - chianti-atomic/ChiantiPy: ChiantiPy is a python package to calculate the radiative properties of astrophysical plasmas based on the CHIANTI atomic database)

In Python I just do (popPlot generates a figure):

import ChiantiPy.core as ch
import numpy as np
import matplotlib.pyplot as plt

t = 10.**(5.8 + 0.05*np.arange(21.))
fe14 = ch.ion('fe_14', temperature=t, eDensity=1.e+9, em=1.e+27)
fe14.popPlot()

In Julia I tried something similar:

using PyCall
ch = pyimport("ChiantiPy.core")
np = pyimport("numpy")
plt = pyimport("matplotlib.pyplot")

t = [10^i for i in 5.8 .+ 0.05 .* range(0.0,20.0,step=1)];
fe14 = ch.ion("fe_14", temperature=t, eDensity=1.e+9, em=1.e+27);
fe14.popPlot()
plt.show()

But when I run it, I get first this error about libGL, though I don’t think that is important?

julia> include("test.jl")                                                                                                                                                                                            
 found PyQt5 widgets                                                                                                                                                                                                 
 using PyQt5 widgets                                                                                                                                                                                                 
libGL error: No matching fbConfigs or visuals found                                                                                                                                                                  
libGL error: failed to load driver: swrast

then, a new window is created, where the figure should go, but no figure is shown. If I try to close it, then I get a warning from the system that “This window might be busy and is not responding. [etc]”.

If I close this window and later I try to generate the plot again via popPlot() then julia itself dies:

julia> fe14.popPlot()                                                                                                                                                                                                
The X11 connection broke: I/O error (code 1)                                                                                                                                                                         
XIO:  fatal IO error 22 (Invalid argument) on X server ":0.0"                                                                                                                                                        
      after 483 requests (481 known processed) with 0 events remaining.

Any suggestions on how to get this working properly?

Thanks,
AdV

2

This sounds like PyPlot works but calling matplotlib directly from PyCall aborts · Issue #665 · JuliaPy/PyCall.jl · GitHub

If so, calling PyCall.pygui_start(:qt_pyqt5) before the pyimports could help.

3

Hi, many thanks, indeed this solves the issue.

I had tried before pygui(:qt_pyqt5) thinking that it was doing the same as what you suggested, but that didn’t fix it.

Many thanks,
AdV