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 educated guess based on above discussions.
Therefore the default type for integer arrays on 64-bit machine (int64) will not produce reasonable output.