Incorrect mix coeffs from get_p

[y1xiaoc]

It seem that the get_p function in libxc.cc is not correctly handling the mix coefficients for multiple aux functionals.
It is mainly this line that make the returned mix_coef all the same.

For example, for pbe0 (id 406), the correct mixing (returned from LibXCFunctional class aux_funcs method) is:

[('gga_x_pbe', 0.75), ('gga_c_pbe', 1.0)]

However, the mix_coef returned from get_p is array([0.75, 0.75]).

[DyeKuu]

Hi @y1xiaoc ! Thank you for your interest in using jax-xc. I'm currently busy with other projects so might not have bandwidth to fix this (Plus I don't have the original dev env so setting this up needs some time). Would you mind putting up a PR for this if you already have idea about how to fix this?

[y1xiaoc]

@DyeKuu thanks for the reply! Since setting up the dev env seems to be a non-trivial task, making a PR would also be out of bandwidth on my side. That said, I managed to bypass the problem by directly calling LibXCFunctional.aux_funcs. So I'm ok to leave it there for now ;)