Using PGSM with Python 3.7

[matteolepur]

Hey Andy,

I get the following error that results from line 68 in kernels.py

TypeError: ufunc 'isinf' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

I changed this

log_q_norm = log_sum_exp(np.array(log_q.values())) -> log_q_norm = log_sum_exp(list(log_q.values()))`

and works fine.

I would create a pull request but I had to swap around the directory because there were importing problems that may be due to my setup

edit:

Looks like we need to wrap any dictionary methods with list

particles_weights.keys() -> list(particles_weights.keys())
particles_weights.values() -> list(particles_weights.values())