optimbase_outstruct

function [f, index]=fun(x, index)
    f = 2*x - 4;
endfunction

function stop=myoutputcmd(state, data)
    iter = data.iteration
    if ( state == "init" ) then
        mprintf ( "=================================\n");
        mprintf ( "Initialization\n");
    elseif ( state == "done" ) then
        mprintf ( "=================================\n");
        mprintf ( "End of Optimization\n");
    end
    fc = data.funccount
    fval = data.fval
    x = data.x
    mprintf ( "Iter. #%3d, Feval #%3d, Fval = %.1e, x = %s \n" , ..
    iter, fc, fval, strcat(string(x)," "));
    stop = %f
endfunction

a = -5;
b = 5;
x0 = (a+b)/2;;

// Creates the object
opt = optimbase_new();

// Configures the object
opt = optimbase_configure(opt,"-numberofvariables",2);
opt = optimbase_configure(opt, "-x0", x0);
opt = optimbase_configure(opt, "-tolxrelative", 10*%eps);
opt = optimbase_configure(opt, "-maxiter", 100);
opt = optimbase_configure(opt, "-function", fun);
opt = optimbase_configure(opt,"-outputcommand", myoutputcmd);

function x=Dicho(opt, a, b)
    xk = optimbase_cget(opt, "-x0");
    [opt, fx0,index] = optimbase_function (opt , xk , 4);
    opt = optimbase_set ( opt , "-fx0" , fx0 );
    opt = optimbase_set ( opt , "-xopt" , x0 );
    opt = optimbase_set ( opt , "-fopt" , fx0 );

    // OutputCmd
    brutedata = optimbase_outstruct ( opt );
    data = tlist(["T_OPTBDATA",...
    "x","fval","iteration","funccount"]);
    data.x = brutedata.x;
    data.fval = brutedata.fval;
    data.iteration = brutedata.iteration;
    data.funccount = brutedata.funccount;
    stop = optimbase_outputcmd (opt , "init" , data );

    while optimbase_get(opt, "-iterations") <optimbase_cget(opt, "-maxiter")
        [opt, f,index] = optimbase_function(opt, xk, 4);
        [opt, g, index] = optimbase_function(opt, a, 4);
        if g*f <=0 then
           b = xk;
        else
            a = xk;
        end
        x = (a+b)/2;
        opt = optimbase_incriter(opt);
        opt = optimbase_set ( opt , "-xopt" , x );
        opt = optimbase_set ( opt , "-fopt" , f );
        temp = abs(x-xk);
        
        if temp < optimbase_cget(opt, "-tolxrelative")
            // OutputCmd
            brutedata = optimbase_outstruct ( opt );
            data = tlist(["T_OPTBDATA",...
            "x","fval","iteration","funccount"]);
            data.x = brutedata.x;
            data.fval = brutedata.fval;
            data.iteration = brutedata.iteration;
            data.funccount = brutedata.funccount;
            stop = optimbase_outputcmd (opt , "done" , data );
            break
        end
        xk = x;
        
        // OutputCmd
        brutedata = optimbase_outstruct ( opt );
        data = tlist(["T_OPTBDATA",...
        "x","fval","iteration","funccount"]);
        data.x = brutedata.x;
        data.fval = brutedata.fval;
        data.iteration = brutedata.iteration;
        data.funccount = brutedata.funccount;
        stop = optimbase_outputcmd (opt , "iter" , data );
    end

endfunction
x = Dicho(opt,a,b)