[Eeglablist] about the pop_runica rank problem

[Joshua Hartshorne]

I am using PCA to identify and remove artifact (mostly blinks) from the
channel data. I use EGI, so my data is automatically average-referenced,
and I haven't seen any reason to change the reference to something else.
Probably for this reason, I get the rank warning from pop_runica that has
been discussed in this forum.

As I said, I'm using PCA ("jader" with 24 components, down from 128
channels). My understanding from previous posts to this listserv is that
since I'm decreasing rank anyway, the rank computation issue doesn't really
affect me. Is that correct? My blink components generally look pretty good,
and removing them from the channel data results in what appears to be
blink-free data, so that increases my confidence that everything is working
correctly. But I'd like to confirm this.

I also had a question about double-precision. Based on the output I get
from pop_runica, it seems that the actual computations (though maybe not
the rank calculation) is done using double-precision, and that I don't need
to manually change my data to double-precision? In any case, I haven't been
able to figure out how to do that manual conversion, so I'd appreciate
directions on that if necessary. I use the most recent update of v10. I
know the latest update of v11 now does the rank calculation with
double-precision, but that seems unnecessary for my purposes, if what I
wrote in the last paragraph is right.

Many thanks for your help.
Josh Hartshorne
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