Adding pi to the functions

[lionel42]

Can we add pi as a function in pysd ?
It would be useful for one of my projects.

Simply adding the following in the function space of pysd/builders/python/python_functions.py

    "pi": (
        "np.pi",
        ("numpy",)),

[enekomartinmartinez]

Hi, sure! This will be an easy addition.

As far as I know, Pi is not defined by Vensim, so I suppose it will only be available in Stella. Could you create a test-model with canonical output that uses pi with an XMILE file? I currently have no access to Vensim or Stella, so I cannot create test models and run them with the original software.

You may need to add your test model here https://github.com/SDXorg/test-models. You have all the instructions in the README. Let me know if you need help :)

[lionel42]

Hi ! Thanks for the reply ,

I also have no access to Stella or Vensim at the moment, actually I am working on another project where I try to create SD models using another program and then run the models with PySD (https://github.com/ScienceGamez/drawio_pysd)

I have seen that only Vensim or Stella models can uploaded at the moment by I could give you maybe a python file contaning an AbstractModel for pysd if that would work for you ? But this might requires a bit too much work for what it is worth.

[enekomartinmartinez]

Great work! Thanks for working on that tool it could be really useful for some people.

About adding pi, I am not sure about adding it to functions as it is not a function, but a constant. Nevertheless, in XMILE it is defined as a function and I don't think that makes sense to include a new builder for constant. I could add it now so it is available for the next release.

[enekomartinmartinez]

Already included it in dev branch. I will wait until we solve some other minor fixes to merge it to master and publish it.

[lionel42]

Thanks a lot !