Mercurial > hg > camir-aes2014
diff toolboxes/FullBNT-1.0.7/nethelp3.3/gpcovar.htm @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
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date | Tue, 10 Feb 2015 15:05:51 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/toolboxes/FullBNT-1.0.7/nethelp3.3/gpcovar.htm Tue Feb 10 15:05:51 2015 +0000 @@ -0,0 +1,64 @@ +<html> +<head> +<title> +Netlab Reference Manual gpcovar +</title> +</head> +<body> +<H1> gpcovar +</H1> +<h2> +Purpose +</h2> +Calculate the covariance for a Gaussian Process. + +<p><h2> +Synopsis +</h2> +<PRE> +cov = gpcovar(net, x) +[cov, covf] = gpcovar(net, x) +</PRE> + + +<p><h2> +Description +</h2> + +<p><CODE>cov = gpcovar(net, x)</CODE> takes +a Gaussian Process data structure <CODE>net</CODE> together with +a matrix <CODE>x</CODE> of input vectors, and computes the covariance +matrix <CODE>cov</CODE>. The inverse of this matrix is used when calculating +the mean and variance of the predictions made by <CODE>net</CODE>. + +<p><CODE>[cov, covf] = gpcovar(net, x)</CODE> also generates the covariance +matrix due to the covariance function specified by <CODE>net.covarfn</CODE> +as calculated by <CODE>gpcovarf</CODE>. + +<p><h2> +Example +</h2> +In the following example, the inverse covariance matrix is calculated +for a set of training inputs <CODE>x</CODE> and is then +passed to <CODE>gpfwd</CODE> so that predictions (with mean <CODE>ytest</CODE> and +variance <CODE>sigsq</CODE>) can be made for the test inputs +<CODE>xtest</CODE>. +<PRE> + +cninv = inv(gpcovar(net, x)); +[ytest, sigsq] = gpfwd(net, xtest, cninv); +</PRE> + + +<p><h2> +See Also +</h2> +<CODE><a href="gp.htm">gp</a></CODE>, <CODE><a href="gppak.htm">gppak</a></CODE>, <CODE><a href="gpunpak.htm">gpunpak</a></CODE>, <CODE><a href="gpcovarp.htm">gpcovarp</a></CODE>, <CODE><a href="gpcovarf.htm">gpcovarf</a></CODE>, <CODE><a href="gpfwd.htm">gpfwd</a></CODE>, <CODE><a href="gperr.htm">gperr</a></CODE>, <CODE><a href="gpgrad.htm">gpgrad</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