<html>
+<!--
+ * Jalview - A Sequence Alignment Editor and Viewer (Version 2.7)
+ * Copyright (C) 2011 J Procter, AM Waterhouse, G Barton, M Clamp, S Searle
+ *
+ * This file is part of Jalview.
+ *
+ * Jalview is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * Jalview is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Jalview. If not, see <http://www.gnu.org/licenses/>.
+-->
<head>
<title>Principal Component Analysis</title>
</head>
<p>In this case, the components are generated by an eigenvector
decomposition of the matrix formed from the sum of BLOSUM scores at each
-aligned position between each pair of sequences. The basic method is
-described in the paper by G. Casari, C. Sander and A. Valencia.
-Structural Biology volume 2, no. 2, February 1995 (<a
+aligned position between each pair of sequences. The matrix is not
+symmetric - elements in the upper diagonal give the sum of scores for
+mutating in one direction, and the lower diagonal is the sum of scores
+for mutating in the other. This is a refinement of the method described
+in the paper by G. Casari, C. Sander and A. Valencia. Structural Biology
+volume 2, no. 2, February 1995 (<a
href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=7749921">pubmed</a>)
and implemented at the SeqSpace server at the EBI.</p>
View→Background Colour.. dialog box. The File menu allows the view
to be saved (<strong>File→Save</strong> submenu) as an EPS or PNG
image or printed, and the original alignment data and matrix resulting
-from its PCA analysis to be retrieved.</p>
+from its PCA analysis to be retrieved. The coordinates for the whole PCA
+space, or just the current view may also be exported as CSV files for
+visualization in another program or further analysis.</p>
<p>A tool tip gives the sequence ID corresponding to a point in the
space, and clicking a point toggles the selection of the corresponding
sequence in the associated alignment window views. Rectangular region
based selection is also possible, by holding the 'S' key whilst
left-clicking and dragging the mouse over the display. By default,
points are only associated with the alignment view from which the PCA
-was calculated, but this may be changed via the <strong>Associate
+was calculated, but this may be changed via the <strong>View→Associate
Nodes</strong> sub-menu.</p>
<p>Initially, the display shows the first three components of the
similarity space, but any eigenvector can be used by changing the
selected dimension for the x, y, or z axis through each ones menu
located below the 3d display.</p>
<p>
+<p>
</body>
</html>
git://source.jalview.org / jalview.git / blobdiff