Mathematics

Setting Minimization Options

You can specify control options that set some minimization parameters by calling fminbnd with the syntax

• x = fminbnd(fun,x1,x2,options)
  

or fminsearch with the syntax

• x = fminsearch(fun,x0,options)
  

options is a structure used by the optimization functions. Use optimset to set the values of the options structure.

• options = optimset('Display','iter');
  

fminbnd and fminsearch use only the options parameters shown in the following table. See the optimset reference page for a complete list of the parameters that are used in the Optimization Toolbox.

options.Display	A flag that determines if intermediate steps in the minimization appear on the screen. If set to 'iter', intermediate steps are displayed; if set to 'off', no intermediate solutions are displayed, if set to final, displays just the final output.
options.TolX	The termination tolerance for x. Its default value is 1.e-4.
options.TolFun	The termination tolerance for the function value. The default value is 1.e-4. This parameter is used by fminsearch, but not fminbnd.
options.MaxIter	Maximum number of iterations allowed.
options.MaxFunEvals	The maximum number of function evaluations allowed. The default value is 500 for fminbnd and 200*length(x0) for fminsearch.

The number of function evaluations, the number of iterations, and the algorithm are returned in the structure output when you provide fminbnd or fminsearch with a fourth output argument, as in

• [x,fval,exitflag,output] = fminbnd(@humps,0.3,1); 
  

or

• [x,fval,exitflag,output] = fminsearch(@three_var,v);
  

Minimizing Functions of Several Variables

Finding Zeros of Functions