Error when writing covariance

[jadball]

I receive the following traceback message when running fitallb.py on one of the included test input files (inf10.inp):

Traceback (most recent call last):
  File "fitallb.py", line 16, in <module>
    gofitallb.run(options)
  File "gofitallb.py", line 121, in run
    fit.refine(far,options.killfile)
  File "fit.py", line 581, in refine
    lsqr.refine()
  File "fit.py", line 138, in refine
    write_output.write_cor(self,i)
  File "write_output.py", line 113, in write_cor
    string = string + '%8f  ' %(lsqr.mg.covariance[('%s' %entry1, '%s' %entry2)]/(n.sqrt(lsqr.mg.covariance[('%s' %entry1, '%s' %entry1)])*n.sqrt(lsqr.mg.covariance[('%s' %entry2, '%s' %entry2)]))) 
TypeError: 'NoneType' object has no attribute '__getitem__'

[jonwright]

I suspect this is related to the change from pyMinuit to iminuit. With a quick check on windows using the pyMinuit from https://www.lfd.uci.edu/~gohlke/pythonlibs/ then the problem goes away. I see line 128 looks a bit suspicious, perhaps scale_errors needs to be debugged.
Can you try removing iminuit and installing pyminuit (from https://github.com/jpivarski/pyminuit) and see if the problem goes away?

[jadball]

Yes, this has fixed the problem - I have a seemingly complete covariance file now. Thanks for your help!

pyminuit was a pain to install though because Minuit itself is so old - I've included the steps I took below just in case anyone else runs into this:

wget http://seal.web.cern.ch/seal/minuit/releases/Minuit-1_7_9.tar.gz
tar xvf Minuit-1_7_9.tar.gz
cd Minuit-1_7_9
./configure CXXFLAGS='-std=gnu++0x'
make
cd ../
git clone https://github.com/jpivarski/pyminuit/
cd pyminuit
python setup.py install --with-minuit=../Minuit-1_7_9

Add the following to ~/.bashrc or equivalent so pyminuit can find the shared libraries for minuit:

export LD_LIBRARY_PATH="/path/to/Minuit-1_7_9/src/.libs:$LD_LIBRARY_PATH"

Then source ~/.bashrc or equivalent and test in python:

$ python
Python 2.7.13 (default, Oct  3 2017, 11:17:53) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-11)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import minuit
>>> 

[jonwright]

OK - thanks - I will leave this open in the hope we will also get it to work in iMinuit soon.

[jadball]

Could you elaborate slightly on where scale_errors is that you mentioned earlier so that I can see whether I can get iminuit compatability working?
We might then be Python-3 compatible.