Add ipu specialised implementations of special functions used in experimental.integrals

graphcore-research / pyscf-ipu

PySCF on IPU

https://github.com/graphcore-research/pyscf-ipu#readme

Apache License 2.0

42 stars 2 forks source link

Add ipu specialised implementations of special functions used in experimental.integrals #93

Open hatemhelal opened 1 year ago

hatemhelal commented 1 year ago

The following special functions are used in the evaluation of electron integrals following the THO methods:

factorial: could we just use the scipy impl? Not available in the v0.3 JAX that we are pinned to.
factorial2: similar, to above: would prefer to use the scipy implementation.
binom: same

AlexanderMath commented 1 year ago

Could you add a list of the needed functions? Assuming they are things like erfc and inv_gamma etc. Do you suspect we'll have to implement them in C?

hatemhelal commented 1 year ago

I think some of the issues might go away by upgrading to 0.4 JAX (or at least there will probably be new issues). I think there should be some cmath functions that could be used at least for the gamma evaluation within the vertex but would need to be tested.