Dear Mo,<div><br></div><div>Ok, why don't you tell us about your data (number of channels, data length, task, recording system, etc). We may be able to find a reason.</div><div><br></div><div>Makoto<br><br><div class="gmail_quote">
2013/3/18 Mo Khalili <span dir="ltr"><<a href="mailto:mokhal@yahoo.co.uk" target="_blank">mokhal@yahoo.co.uk</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div style="font-size:12pt;font-family:times new roman,new york,times,serif"><div style="font-family:'times new roman','new york',times,serif;font-size:12pt">Hi Makoto,</div><div style="font-family:'times new roman','new york',times,serif;font-size:12pt">
<br></div><div style="background-color:transparent">yes, I used the same dataset with multiple runs of ICA (different decompositions); there wasn't any significant change in the results.</div><div style="background-color:transparent">
the absolute correlation between pairs of components ,resulting from FastICA, is near zero, so the components are well decorrelated. However, in the infomax the result shows a significantly higher correlation between IC pairs.</div>
<span class="HOEnZb"><font color="#888888"><div style="font-family:'times new roman','new york',times,serif;font-size:12pt"><br></div><div style="font-style:normal;font-size:16px;background-color:transparent;font-family:'times new roman','new york',times,serif">
Mo</div> </font></span><div style="font-family:'times new roman','new york',times,serif;font-size:12pt"> <div style="font-family:'times new roman','new york',times,serif;font-size:12pt"> <div dir="ltr">
<font face="Arial"> <hr size="1"><div class="hm HOEnZb"> <b><span style="font-weight:bold">From:</span></b> Makoto Miyakoshi <<a href="mailto:mmiyakoshi@ucsd.edu" target="_blank">mmiyakoshi@ucsd.edu</a>><br> <b><span style="font-weight:bold">To:</span></b> Mo Khalili <<a href="mailto:mokhal@yahoo.co.uk" target="_blank">mokhal@yahoo.co.uk</a>> <br>
<b><span style="font-weight:bold">Cc:</span></b> "<a href="mailto:eeglablist@sccn.ucsd.edu" target="_blank">eeglablist@sccn.ucsd.edu</a>" <<a href="mailto:eeglablist@sccn.ucsd.edu" target="_blank">eeglablist@sccn.ucsd.edu</a>> <br>
<b><span style="font-weight:bold">Sent:</span></b> Tuesday, 19 March 2013, 0:23<br> <b><span style="font-weight:bold">Subject:</span></b> Re: [Eeglablist] paradox in whitening<br> </div></font><div class="hm HOEnZb"> </div>
</div><div><div class="h5"> <br><div>Dear
Mo,<div><br></div><div><font color="#222222" face="arial, sans-serif">That's not consistent with Delorme et al. (2012) in PLoS One. I wonder why too. Did you use the same data to test two different weight matrices?</font></div>
<div><font color="#222222" face="arial, sans-serif"><br></font></div><div><font color="#222222" face="arial, sans-serif">Makoto</font></div><div><br></div><div><br><br><div>2013/3/18 Mo Khalili <span dir="ltr"><<a rel="nofollow" href="mailto:mokhal@yahoo.co.uk" target="_blank">mokhal@yahoo.co.uk</a>></span><br>
<blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:'times new roman','new york',times,serif"><div><span style="font-family:arial,sans-serif;color:rgb(34,34,34);font-size:13px">Hi,</span><br>
</div><div style="font-size:12pt"><div style="font-size:12pt"><div><div><div style="font-size:12pt">
<div style="font-size:12pt"><div style="font-size:12pt"><div><div style="font-size:12pt">
<div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)">I have a general query about performance of ICA algorithms.</div>
<div><font color="#222222" face="arial, sans-serif">As I know FastICA is trying to estimate sources based
on maximizing the non-gaussianity while, infoamx is trying to estimate the components based on minimizing mutual information between sources. What wonders me is , when I calculated the mutual information between ICs, the averaged mutual information between pairs of ICs in FastICA is lower than ICs estimated by infomax. Additionally when I calculate
the correlation between pairs of the estimated ICs, the averaged absolute correlation between ICs obtained by FastICA is significantly lower than infomax.</font></div><div><font color="#222222" face="arial, sans-serif">in my opinion this result speculates, the whitening(sphering) step in the infomax is different from FastICA, and it does not perform the same. </font></div>
<div><font color="#222222" face="arial, sans-serif">However, when I look at the codes of FastICA and infomax, both have used the same method (and functions) for whitening.</font></div><div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)">
I appreciate it if anyone can help me through understanding the reason.</div><div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)"><br></div><div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)">
Regards,</div><div style="font-family:arial,sans-serif;font-size:13px;color:rgb(34,34,34)">Mo</div></div></div><br><br> </div> </div> </div></div></div><br><br> </div> </div> </div></div><br>_______________________________________________<br>
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<br clear="all"><div><br></div>
-- <br>Makoto Miyakoshi<br>JSPS Postdoctral Fellow for Research Abroad<br>Swartz Center for Computational Neuroscience<br>Institute for Neural Computation, University of California San Diego<br>
</div>
</div><br><br> </div></div></div> </div> </div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>Makoto Miyakoshi<br>JSPS Postdoctral Fellow for Research Abroad<br>Swartz Center for Computational Neuroscience<br>
Institute for Neural Computation, University of California San Diego<br>
</div>