<div dir="ltr">Dear all,<div><br></div><div>here is a snippet from the ft_componentanalysis code which may prove useful to anybody facing this situation</div><div><br></div><div>[from ft_componentanalysis)</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">% compute data cross-covariance matrix<br>    C = (dat*dat')./(size(dat,2)-1);<br>    <br>    % eigenvalue decomposition (EVD)<br>    [E,D] = eig(C);<br>    <br>    % sort eigenvectors in descending order of eigenvalues<br>    d = cat(2,(Nchan)',diag(D));<br>    d = sortrows(d,[-2]);<br></blockquote><div><br></div><div>one could then use something like this to obtain the percentage of explained variance for each component.. </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">    varianza=d(Nchan,2)/sum(diag(C));]</blockquote><div><br></div><div>paz! </div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-02-05 15:56 GMT+01:00 Constantino Méndez Bértolo <span dir="ltr"><<a href="mailto:constantino.mendezbertolo@ctb.upm.es" target="_blank">constantino.mendezbertolo@ctb.upm.es</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>tl;dr: anybody knows whether this info is stored (or not) and where? thx</div><div><br></div>Queridos fieldtrippers,<div><br></div><div>I am trying to find where the info about the amount of variance that each component explains is stored (if it is) after running ft_componentanalysis (method='pca')</div><div><br></div><div>I know the interesting data is in two fields: topo + unmixing. May it happen that I am supposed to derive the variance explained by each component using some kind of mathematical sorcery and this values.</div><div><br></div><div>If my question is too naive, I apologize, I think that the channels (actually 'components') of the output structure are sorted in descending order of variance explained during the call to the function, I searched there and in ft_databrowser unfructiosly. Also parsed the mailing list (there are two other answered questions <br></div><div>[<a href="http://mailman.science.ru.nl/pipermail/fieldtrip/2012-July/005409.html" target="_blank">http://mailman.science.ru.nl/pipermail/fieldtrip/2012-July/005409.html</a>]</div><div>[<a href="http://mailman.science.ru.nl/pipermail/fieldtrip/2012-January/004706.html" target="_blank">http://mailman.science.ru.nl/pipermail/fieldtrip/2012-January/004706.html</a>]<br></div><div><br></div><div>Peace,</div><span class="HOEnZb"><font color="#888888"><div><div><br></div>-- <br><div><div><font>Constantino Méndez-Bértolo<br></font></div><div><font>Laboratorio de Neurociencia Clínica,</font><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent"> Centro de Tecnología Biomédica (CTB)</span></font></div><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent">Parque Científico y Tecnológico d</span></font><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent">e la UPM, </span></font><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent">Campus de Montegancedo</span></font></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent">28223 Pozuelo de</span></font><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent"> Alarcón, Madrid, SPAIN</span></font></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><br></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline;background-color:transparent"><img src="https://docs.google.com/a/ctb.upm.es/uc?id=0B975KkJxc3ZdOGI2ODg4OTItYTYwNC00MDY4LTk0YzQtZDQzYzUwZjQwMWYx&export=download&hl=es" height="40" width="131"></span></font></p></div>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div><font>Constantino Méndez-Bértolo<br></font></div><div><font>Laboratorio de Neurociencia Clínica,</font><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> Centro de Tecnología Biomédica (CTB)</span></font></div><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Parque Científico y Tecnológico d</span></font><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">e la UPM, </span></font><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">Campus de Montegancedo</span></font></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline">28223 Pozuelo de</span></font><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"> Alarcón, Madrid, SPAIN</span></font></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><br></p><p dir="ltr" style="text-align:justify;margin-top:0pt;margin-bottom:0pt"><font><span style="font-family:Arial;color:rgb(0,0,0);background-color:transparent;font-weight:normal;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:baseline"><img src="https://docs.google.com/a/ctb.upm.es/uc?id=0B975KkJxc3ZdOGI2ODg4OTItYTYwNC00MDY4LTk0YzQtZDQzYzUwZjQwMWYx&export=download&hl=es" height="40" width="131"></span></font></p></div>
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