Mercurial > hg > camir-aes2014

diff toolboxes/FullBNT-1.0.7/nethelp3.3/gtmem.htm @ 0:e9a9cd732c1e tip

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
parents
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolboxes/FullBNT-1.0.7/nethelp3.3/gtmem.htm	Tue Feb 10 15:05:51 2015 +0000
@@ -0,0 +1,88 @@
+<html>
+<head>
+<title>
+Netlab Reference Manual gtmem
+</title>
+</head>
+<body>
+<H1> gtmem
+</H1>
+<h2>
+Purpose
+</h2>
+EM algorithm for Generative Topographic Mapping.
+
+<p><h2>
+Synopsis
+</h2>
+<PRE>
+
+[net, options, errlog] = gtmem(net, t, options)
+</PRE>
+
+
+<p><h2>
+Description
+</h2>
+<CODE>[net, options, errlog] = gtmem(net, t, options)</CODE> uses the Expectation
+Maximization algorithm to estimate the parameters of
+a GTM defined by a data structure <CODE>net</CODE>.
+The matrix <CODE>t</CODE> represents the data whose expectation
+is maximized, with each row corresponding to a vector.  It is assumed
+that the latent data <CODE>net.X</CODE> has been set following a call to
+<CODE>gtminit</CODE>, for example.
+  
+The optional parameters have the following interpretations.
+
+<p><CODE>options(1)</CODE> is set to 1 to display error values; also logs error 
+values in the return argument <CODE>errlog</CODE>.
+If <CODE>options(1)</CODE> is set to 0,
+then only warning messages are displayed.  If <CODE>options(1)</CODE> is -1,
+then nothing is displayed.
+
+<p><CODE>options(3)</CODE> is a measure of the absolute precision required of the error
+function at the solution. If the change in log likelihood between two steps of
+the EM algorithm is less than this value, then the function terminates.
+
+<p><CODE>options(14)</CODE> is the maximum number of iterations; default 100.
+
+<p>The optional return value <CODE>options</CODE> contains the final error value 
+(i.e. data log likelihood) in
+<CODE>options(8)</CODE>.  
+
+<p><h2>
+Examples
+</h2>
+The following code fragment sets up a GTM, initialises
+the latent data sample and RBF
+parameters from the data, sets the options and trains the model.
+<PRE>
+
+% Create and initialise GTM model
+net = gtm(latentdim, nlatent, datadim, numrbfcentres, ...
+   'gaussian', 0.1);
+
+<p>options = foptions;
+options(1) = -1;
+options(7) = 1;    % Set width factor of RBF
+net = gtminit(net, options, data, 'regular', latentshape, [4 4]);
+
+<p>options = foptions;
+options(14) = 30;
+options(1) = 1;
+[net, options] = gtmem(net, data, options);
+</PRE>
+
+
+<p><h2>
+See Also
+</h2>
+<CODE><a href="gtm.htm">gtm</a></CODE>, <CODE><a href="gtminit.htm">gtminit</a></CODE><hr>
+<b>Pages:</b>
+<a href="index.htm">Index</a>
+<hr>
+<p>Copyright (c) Ian T Nabney (1996-9)
+
+
+</body>
+</html>
\ No newline at end of file