Support for PyTorch models

[Ramaravind K M]

Thanks for this library! I see you support LR and MLP models from sklearn currently, but can you give some pointers on how to make it work with PyTorch or TensorFlow models?

I checked generateSATExplanations.py and found that you convert a model to a logic formula in modelConversion.py, but do so only for four model classes from sklearn. How to replicate this for any model from say PyTorch? In particular, how to update mlp2formula(model, model_symbols) method?

[Amir-Hossein Karimi]

Indeed, the conversion from sklearn models to pysmt formulas was done manually and using available pysmt API and a bit of trial and error + many assertions to make sure behavior is replicated correctly. I imagine the same should be done for pytorch models. A good starting point to see available pysmt API is the factory.py file in their codebase. An alternative (perhaps easier) route, would be to convert a pytorch model into an equivalent sklearn model, and then use mlp2formula to go from sklearn model to pysmt formula. Hope this helps!