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| author | ziejd2 | 2017-09-28 15:04:40 -0500 |
|---|---|---|
| committer | ziejd2 | 2017-09-28 15:04:40 -0500 |
| commit | 8070dc963753142bb86c4ed698d91fd623ed28e7 (patch) | |
| tree | d0f6dd8fc46a49b819aa55c1a90faa14d8448883 /sourcecodes/bnt-master/nethelp3.3/evidence.htm | |
| parent | 7cc31810d53176e805532b2789955f4eedbce6bb (diff) | |
| download | BNW-8070dc963753142bb86c4ed698d91fd623ed28e7.tar.gz | |
BNW using Octave instead of Matlab.
This version of BNW should perform the same as the original version. The only difference is that it uses Octave instead of Matlab when running BayesNet Toolbox during parameter learning. I am calling this BNW_1.02. It can be accessed at: compbio.uthsc.edu/BNW_1.02
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| -rw-r--r-- | sourcecodes/bnt-master/nethelp3.3/evidence.htm | 57 |
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diff --git a/sourcecodes/bnt-master/nethelp3.3/evidence.htm b/sourcecodes/bnt-master/nethelp3.3/evidence.htm new file mode 100644 index 00000000..7e319484 --- /dev/null +++ b/sourcecodes/bnt-master/nethelp3.3/evidence.htm @@ -0,0 +1,57 @@ +<html> +<head> +<title> +Netlab Reference Manual evidence +</title> +</head> +<body> +<H1> evidence +</H1> +<h2> +Purpose +</h2> +Re-estimate hyperparameters using evidence approximation. + +<p><h2> +Synopsis +</h2> +<PRE> +[net] = evidence(net, x, t) +[net, gamma, logev] = evidence(net, x, t, num) +</PRE> + + +<p><h2> +Description +</h2> +<CODE>[net] = evidence(net, x, t)</CODE> re-estimates the +hyperparameters <CODE>alpha</CODE> and <CODE>beta</CODE> by applying Bayesian +re-estimation formulae for <CODE>num</CODE> iterations. The hyperparameter +<CODE>alpha</CODE> can be a simple scalar associated with an isotropic prior +on the weights, or can be a vector in which each component is +associated with a group of weights as defined by the <CODE>index</CODE> +matrix in the <CODE>net</CODE> data structure. These more complex priors can +be set up for an MLP using <CODE>mlpprior</CODE>. Initial values for the iterative +re-estimation are taken from the network data structure <CODE>net</CODE> +passed as an input argument, while the return argument <CODE>net</CODE> +contains the re-estimated values. + +<p><CODE>[net, gamma, logev] = evidence(net, x, t, num)</CODE> allows the re-estimation +formula to be applied for <CODE>num</CODE> cycles in which the re-estimated +values for the hyperparameters from each cycle are used to re-evaluate +the Hessian matrix for the next cycle. The return value <CODE>gamma</CODE> is +the number of well-determined parameters and <CODE>logev</CODE> is the log +of the evidence. + +<p><h2> +See Also +</h2> +<CODE><a href="mlpprior.htm">mlpprior</a></CODE>, <CODE><a href="netgrad.htm">netgrad</a></CODE>, <CODE><a href="nethess.htm">nethess</a></CODE>, <CODE><a href="demev1.htm">demev1</a></CODE>, <CODE><a href="demard.htm">demard</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 |