[FieldTrip] MaxFilter and ICA preprocessing

[Frédéric Roux]

Dear all,

after preprocessing my MEG data (Elekta Neuromag) with MaxFilter, I noticed that the ICA decomposition
takes longer than if the data hasn't been preprocessed with MF.

As a side note: I've taken care of reducing the dimensionality of the data to cfg.runica.pca = rank(data.trial{1}*data.trial{1}'), as I've read in previous posts that otherwise the results of the ICA decomposition can contain complex values.

My questions are: 

1) is the fact that the ICA training takes longer normal?

2) why does the ICA training take longer in the case of MF preprocessing?

Sorry for cross-posting on both lists, I'm just hoping to get an answer asap.


Best,
Fred


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