Shrinks the simplex.
opt = optimsimplex_shrink(opt, fun, [sigma]) [opt, data] = optimsimplex_shrink(opt, fun, sigma, data)
The current simplex object of TSIMPLEX type (tlist).
The function to compute at vertices.
The fun
function is expected to have the following
input and output arguments:
y = myfunction (x)
The shrinkage coefficient (optional). The default value is 0.5.
User-defined data passed to the function (optional).
If data
is provided, it is passed to the callback function
both as an input and output argument. In that case, the function must have the
following header :
[y, data] = myfunction (x, data)
The data input parameter may be used if the function uses some additional parameters. It is returned as an output parameter because the function may modify the data while computing the function value. This feature may be used, for example, to count the number of times that the function has been called.
The optimsimplex_shrink
function shrinks the simplex with given
coefficient sigma and returns an updated simplex. The shrink is performed with
respect to the first point in the simplex.
function y=rosenbrock(x) y = 100*(x(2)-x(1)^2)^2 + (1-x(1))^2; endfunction s1 = optimsimplex_new (); simplex = [ -12 0. 0. 0 1. 0. 0 0. 1. ]; s1 = optimsimplex_setall ( s1 , simplex ); s1 = optimsimplex_shrink ( s1 , rosenbrock ); res = optimsimplex_getall ( s1 ); disp(res) s1 = optimsimplex_destroy(s1); | ![]() | ![]() |