Total different response between pyspice and Hspice？

[Hejie-Guo]

Environment (OS, Python version, PySpice version, simulator)

Unix, python3.8,
I am using the same parameter of BJT Gummel Poon model do get the input and output I-V curve, but it seems that the result is totally different between pyspice and Hspice? is there any difference between these two software?

[metroid120]

I am not involved in Pyspice, but with Ngspice. The Gummel Poon model is not well-standardized and not a CMC model, so it is absolutely possible that with the same model parameters, two simulators will give different output. The introduction of standard models by CMC tries to overcome, amongst other issues, such incompatibility issues.

You should check in detail the Hspice and Ngspice implementation to make sure they are the same.