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1 <html>
2 <head>
3 <title>
4 Netlab Reference Manual ppca
5 </title>
6 </head>
7 <body>
8 <H1> ppca
9 </H1>
10 <h2>
11 Purpose
12 </h2>
13 Probabilistic Principal Components Analysis
14
15 <p><h2>
16 Synopsis
17 </h2>
18 <PRE>
19 [var, U, lambda] = pca(x, ppca_dim)
20 </PRE>
21
22
23 <p><h2>
24 Description
25 </h2>
26
27 <CODE>[var, U, lambda] = ppca(x, ppca_dim)</CODE> computes the principal component
28 subspace <CODE>U</CODE> of dimension <CODE>ppca_dim</CODE> using a centred
29 covariance matrix <CODE>x</CODE>. The variable <CODE>var</CODE> contains
30 the off-subspace variance (which is assumed to be spherical), while the
31 vector <CODE>lambda</CODE> contains the variances of each of the principal
32 components. This is computed using the eigenvalue and eigenvector
33 decomposition of <CODE>x</CODE>.
34
35 <p><h2>
36 See Also
37 </h2>
38 <CODE><a href="eigdec.htm">eigdec</a></CODE>, <CODE><a href="pca.htm">pca</a></CODE><hr>
39 <b>Pages:</b>
40 <a href="index.htm">Index</a>
41 <hr>
42 <p>Copyright (c) Ian T Nabney (1996-9)
43
44
45 </body>
46 </html>