Various ICA warnings and failures

Sameer Walawalkar sameer at ANDREW.CMU.EDU
Fri Feb 23 17:09:44 CET 2007


This mail has 3  questions related to implementing ICA is fieldtrip.

I am now getting the following warnings from runica
I am getting these messages while doing ICA on a datafile which contains
sss MaxFiltered data (Elekta Neuromag).  When I visually inspect the
independent components, they seem fairly identical to me. Their basic time
structure seems to be same, just the scale is different.

Prior to this, I had run ICA on the same datafile but with no MaxFiltering
(or SSP projection for that matter).

Final training data range: -0.00443438 to 0.00355995
Computing the sphering matrix...
Warning: Matrix is close to singular or badly scaled.
          Results may be inaccurate. RCOND = 2.156998e-29.
> In runica at 774
   In componentanalysis at 331
Starting weights are the identity matrix ...
Sphering the data ...
Beginning ICA training ...
Data has rank 286. Cannot compute 307 components.
Warning: Matrix is close to singular or badly scaled.
          Results may be inaccurate. RCOND = 2.155705e-29.
> In componentanalysis at 437
total time in componentanalysis 160.6 seconds

binica on this datafile just hangs, after one learning, it sends nan and
just hangs.

Fast ICA is giving me following errors
>> compRR_One_fastica_sss = componentanalysis(cfg,dataRR_One);
Warning: cannot determine whether the FASTICA toolbox is present
> In fieldtrip/private/hastoolbox at 121
   In componentanalysis at 176
Warning: adding FASTICA toolbox to your Matlab path
> In fieldtrip/private/hastoolbox at 145
   In componentanalysis at 176
Warning: Name is nonexistent or not a directory: fastica.
> In path at 113
   In addpath at 100
   In fieldtrip/private/hastoolbox at 146
   In componentanalysis at 176
selecting 307 channels
baseline correcting data
concatenating data..............................
concatenated data matrix size 307x120030
starting decomposition using fastica
Number of signals: 307
Number of samples: 120030
Calculating covariance...
??? Error using ==> componentanalysis
call to fastica failed

But when I do
>> which fastica

>> exist('fastica','file') (as seen in hastoolbox)

ans =



p.s: I am currently running varimax on the sssed data and binica on the
non sssed to see what happens.

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