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Hi Jeroen,<div><br class="webkit-block-placeholder"></div><div>at present componentanalysis using a predetermined mixing matrix requires this to be a square matrix.</div><div><br></div><div>Until this is changed you can use the following workaround (hacky but sound, tried and tested at the FCDC):</div><div><br class="webkit-block-placeholder"></div><div>1) call componentanalysis to get your comp.topo = [204-by-64] matrix</div><div><br class="webkit-block-placeholder"></div><div>2) do an orthogonal expansion of matrix comp.topo, this gives you a 204-by-204 matrix where the columns 65:204 form a subspace that is orthogonal to the subspace formed by the first 64 columns (so by definition the signals living in each are uncorrelated), and which corresponds to the subspace of signal that you threw out by doing PCA and retaining only the first 64 components. There should be a file in fieldtrip/private called "expand_orthogonal.m" containing a function which does this for you (if it is not there let me know and I'll email it you separately).</div><div><br></div><div>3) now call componentanalysis again on whichever dataset with cfg.method = "predetermined mixing matrix" and cfg.topo = expanded(comp.topo) and just ignore components 65:204 since they are a mixture of the "garbage" that was ignored by the ICA anyway (the ICA only separated the signals in the subspace spanned by the first 64 PCs, which in practice means that the ICs you estimate are mutually statistically independent but only uncorrelated w.r.t. the PCs 65:204 !!!).</div><div><br></div><div><br class="webkit-block-placeholder"></div><div>Hope that helps,</div><div>Christian</div><div><br class="webkit-block-placeholder"></div><div><br></div><div><br class="webkit-block-placeholder"></div><div><div><div>On 8 Feb 2008, at 10:52, Jeroen Geuze wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Hello all,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I am trying to use ICA with a predetermined mixing matrix on my data. I have the following situation: I want to use Cluster Analysis on the components of two of my datasets. In this case, you want to have the same components for both datasets. I have measured with 256 electrodes and after removing the bad electrodes, 204 are left. I then run ICA with the PCA setting to 64. I run this on my two appended datasets. Then I want to use the mixing matrix found there to do ICA on each of my two separate datasets. But because I go from 204 electrodes to 64 components, the weights matrix is not square. Is there a way to use componentanalysis with a non-square predetermined mixing matrix? Or is there another way to get the components of the appended datasets into the two separate datasets?</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Regards,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Jeroen Geuze</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">--</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">J. Geuze M.Sc.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Cognitive Artificial Intelligence</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">NICI, Radboud University Nijmegen</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Montessorilaan 3, Room B.02.28</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">P.O.Box 9104</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">6500 HE Nijmegen</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">The Netherlands</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Tel: +31(0)24 3611938</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="mailto:J.Geuze@nici.ru.nl">J.Geuze@nici.ru.nl</a></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">----------------------------------</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">The aim of this list is to facilitate the discussion between users of the FieldTrip<span class="Apple-converted-space"> </span>toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also <a href="http://listserv.surfnet.nl/archives/fieldtrip.html">http://listserv.surfnet.nl/archives/fieldtrip.html</a> and <a href="http://www.ru.nl/fcdonders/fieldtrip">http://www.ru.nl/fcdonders/fieldtrip</a>.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> </blockquote></div><br></div><br><br><div> <span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>----------------------------------------------------------------------</div><div>Christian Hesse, PhD, MIEEE</div><div><br class="khtml-block-placeholder"></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">F.C. Donders Centre for Cognitive Neuroimaging </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">P.O. Box 9101 </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">NL-6500 HB Nijmegen </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">The Netherlands</div><div><br class="khtml-block-placeholder"></div><div>Tel.: +31 (0)24 36 68293</div><div>Fax: +31 (0)24 36 10989</div><div><br class="khtml-block-placeholder"></div><div>Email: <a href="mailto:c.hesse@fcdonders.ru.nl">c.hesse@fcdonders.ru.nl</a></div><div>Web: <a href="http://www.fcdonders.ru.nl">www.fcdonders.ru.nl</a></div><div>----------------------------------------------------------------------</div><div><br class="khtml-block-placeholder"></div><div><br class="khtml-block-placeholder"></div><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "></span><br class="Apple-interchange-newline"></span></span></span></span></span> </div><br></body></html><p>----------------------------------</p>
<p>The aim of this list is to facilitate the discussion between users of the FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis.</p>
<p> http://listserv.surfnet.nl/archives/fieldtrip.html</p>
<p> http://www.ru.nl/fcdonders/fieldtrip/</p>