Mercurial > hg > camir-aes2014
diff toolboxes/FullBNT-1.0.7/nethelp3.3/linemin.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/linemin.htm Tue Feb 10 15:05:51 2015 +0000 @@ -0,0 +1,74 @@ +<html> +<head> +<title> +Netlab Reference Manual linemin +</title> +</head> +<body> +<H1> linemin +</H1> +<h2> +Purpose +</h2> +One dimensional minimization. + +<p><h2> +Description +</h2> +<CODE>[x, options] = linemin(f, pt, dir, fpt, options)</CODE> uses Brent's +algorithm to find the minimum of the function <CODE>f(x)</CODE> along the +line <CODE>dir</CODE> through the point <CODE>pt</CODE>. The function value at the +starting point is <CODE>fpt</CODE>. The point at which <CODE>f</CODE> has a local minimum +is returned as <CODE>x</CODE>. The function value at that point is returned +in <CODE>options(8)</CODE>. + +<p><CODE>linemin(f, pt, dir, fpt, options, p1, p2, ...)</CODE> allows +additional arguments to be passed to <CODE>f()</CODE>. + +<p>The optional parameters have the following interpretations. + +<p><CODE>options(1)</CODE> is set to 1 to display error values. + +<p><CODE>options(2)</CODE> is a measure of the absolute precision required for the value +of <CODE>x</CODE> at the solution. + +<p><CODE>options(3)</CODE> is a measure of the precision required of the objective +function at the solution. Both this and the previous condition must be +satisfied for termination. + +<p><CODE>options(14)</CODE> is the maximum number of iterations; default 100. + +<p><h2> +Examples +</h2> +An example of the use of this function to find the minimum of a function +<CODE>f</CODE> in the direction <CODE>sd</CODE> can be found in <CODE>conjgrad</CODE> +<PRE> + +x = linemin(f, xold, sd, fold, lineoptions); +</PRE> + + +<p><h2> +Algorithm +</h2> + +Brent's algorithm uses a mixture of quadratic interpolation and golden +section search to find the minimum of a function of a single variable once +it has been bracketed (which is done with <CODE>minbrack</CODE>). This is adapted +to minimize a function along a line. +This implementation +is based on that in Numerical Recipes. + +<p><h2> +See Also +</h2> +<CODE><a href="conjgrad.htm">conjgrad</a></CODE>, <CODE><a href="minbrack.htm">minbrack</a></CODE>, <CODE><a href="quasinew.htm">quasinew</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