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<body lang="en-CH" link="#0563C1" vlink="#954F72"><p><span style="padding: 3px 10px; border-radius: 5px; color: #ffffff; font-weight: bold; display: inline-block; background-color: #ff0000;"> External Email - Use Caution </span></p><p></p>
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<p class="MsoNormal">Dear MNE team<span lang="EN-GB"> and users,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I currently working on testing MNE ICA algorithms for different case ( noise level, sample length)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I would like to extract the mixing matrix M used by ica.apply to go back from ica source space to recording space such as
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Recordings = M * Sources<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I ended with this formula :<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">M = pre_whitener_ * (pca_components_)<sup> -1
</sup>* mixing <span style="color:red">[1]</span><o:p></o:p></span></p>
<p class="MsoNormal"><sup><span lang="EN-GB"><o:p> </o:p></span></sup></p>
<p class="MsoNormal"><span lang="EN-GB">And implemented it with python using:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">pre_whitener_ = getattr(ica, "pre_whitener_" )<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">whitenning_matrix = np.eye(len(pre_whitener_))*pre_whitener_<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">mixing = getattr(ica, "mixing_matrix_" )<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">pca_components_ = getattr(ica, "pca_components_" )
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">M = np.dot (whitenning_matrix, np.dot(np.linalg.inv(pca_components_), mixing ) )<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">But I weren’t able to successfully reconstruct the signal by using the following line:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Records_from_ica = np.dot(M, ica.get_sources(Raw).get_data())<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">It’s probably a problem in the formula <span style="color:red">
[1] </span>, but I can’t find any solution<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Do you have any idea on how to get the mixing matrix used by the ica.apply function ? I looked up the code, but it didn’t completely understand it<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Thanks for your help,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Victor<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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