[FieldTrip] problem with ICA

Hwee Ling Lee hweeling.lee at gmail.com
Thu Jan 16 13:22:14 CET 2014

Dear all,

I've collected data using a 128 channel EEG cap, and I tried to perform ICA
on the data. However, I got an error message with fieldtrip on Matlab.
Here's the error message:

the input is raw data with 127 channels and 1 trials
selecting 123 channels
baseline correcting data
scaling data with 1 over 148.247820
concatenating data.
concatenated data matrix size 123x2789000
starting decomposition using runica

Input data size [123,2789000] = 123 channels, 2789000 frames/nFinding 123
ICA components using logistic ICA.
Decomposing 184 frames per ICA weight ((15129)^2 = 2789000 weights, Initial
learning rate will be 0.001, block size 75.
Learning rate will be multiplied by 0.9 whenever angledelta >= 60 deg.
More than 32 channels: default stopping weight change 1E-7
Training will end when wchange < 1e-07 or after 512 steps.
Online bias adjustment will be used.
Removing mean of each channel ...
Final training data range: -3.46556 to 6.39436
Computing the sphering matrix...
Starting weights are the identity matrix ...
Sphering the data ...
Beginning ICA training ...
Data has rank 119. Cannot compute 123 components.
the call to "ft_componentanalysis" took 148 seconds

Could someone please let me know what went wrong?


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