EHN: compute_ica add decimation parameter to test

[kingjr]

@dengemann we were speaking of adding a parameter to the run_ica function, so as to decimate the epoched ecg and eog.

Would it not be more efficient to decimate the raw data before passing it to compute data (and redecimate it one more time for the ica.fit)?

[dengemann]

Would it not be more efficient to decimate the raw data before passing it to compute data (and redecimate it one more time for the ica.fit)?

ICA handles the decimation internally. We don't have an officially approved method for decimating Raw (although it would be more or less trivial to do it). The best solution to me would be to check if Raw(..., preload=False) is supported throughout the ICA pipeline. This would be the most elegant solution to me. Then ICA and the epochs functions would use the decimation on reading the data.