TGraphAsymmErrors can not convert argument in with pyROOT

[ksmith]

This may have to do with the type of the variables. @adsherman can you post a (non)working example?

https://sft.its.cern.ch/jira/browse/ROOT-9040

pyROOT TMultiGraph Segmentation Fault

I ran into the issue of “proper” types again and had to reteach myself what was learned above. I wanted to clarify the situation for myself and others who might run into this. At the moment the dtype of the two numpy arrays passed to TGraph must match. In addition, only certain dtype values produce reasonable output: Type Constructor Chosen Output int32 int* Good int64 double* Bad float32 int* Bad float64 double* Good * The constructor chosen may not be correct, but is an educa…