[FieldTrip] error with runica

[Phyllis Mania]

Dear all,

 

I have a problem with running an ICA in one of my subjects (EEG, 70
channels, 878 trials), even though it was preprocessed exactly like all
others (same number of channels, similar number of trials). When calling
ft_componentanalysis with 'runica' the learning rate gets as low as
3.09032e-05 before it actually starts with step 1. It takes up to 512 steps
(very slowly) but the lrate never changes from 0 after the first few steps
while the angledelta is constant at 22.3.

 

In the the end I get the following warning:

 

Warning: Matrix is close to singular or badly scaled. Results may be
inaccurate. RCOND = 1.190323e-16.

> In runica at 1430

In ft_componentanalysis at 463

 

When trying to plot the components with ft_topoplotTFR only one black &
white head shows up and the following error:

 

Error using surf (line 75)

X, Y, Z, and C cannot be complex.

 

Error in ft_plot_topo (line 251)

  h = surf(Xi-deltax/2,Yi-deltay/2,zeros(size(Zi)), Zi, 'EdgeColor', 'none',
'FaceColor', shading);

 

Error in topoplot_common (line 704)

  ft_plot_topo(chanX,chanY,datavector,'interpmethod',cfg.interpolation,...

 

Error in ft_topoplotTFR (line 185)

[cfg] = topoplot_common(cfg, varargin{:});

 

Error in ft_topoplotIC (line 148)

    ft_topoplotTFR(cfg, varargin{:});

 

 

Running 'fastica' seems to work fine. I read about the issue with some 64
bit computers but the workaround with pop_runica didn't work for me.

 

Thank you in advance!

 

Best,

Phyllis

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