annotate toolboxes/FullBNT-1.0.7/netlab3.3/rosegrad.m @ 0:e9a9cd732c1e tip

first hg version after svn
author wolffd
date Tue, 10 Feb 2015 15:05:51 +0000
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wolffd@0 1 function g = rosegrad(x)
wolffd@0 2 %ROSEGRAD Calculate gradient of Rosenbrock's function.
wolffd@0 3 %
wolffd@0 4 % Description
wolffd@0 5 % G = ROSEGRAD(X) computes the gradient of Rosenbrock's function at
wolffd@0 6 % each row of X, which should have two columns.
wolffd@0 7 %
wolffd@0 8 % See also
wolffd@0 9 % DEMOPT1, ROSEN
wolffd@0 10 %
wolffd@0 11
wolffd@0 12 % Copyright (c) Ian T Nabney (1996-2001)
wolffd@0 13
wolffd@0 14 % Return gradient of Rosenbrock's test function
wolffd@0 15
wolffd@0 16 nrows = size(x, 1);
wolffd@0 17 g = zeros(nrows,2);
wolffd@0 18
wolffd@0 19 g(:,1) = -400 * (x(:,2) - x(:,1).^2) * x(:,1) - 2 * (1 - x(:,1));
wolffd@0 20 g(:,2) = 200 * (x(:,2) - x(:,1).^2);