else
        xs = xt + (xt - x);
        x = xt;
        if( feval(f,xs) < feval(f,x) )
            for i = 1 : n
                xsp = xs + k*d(:,i);
                if( feval(f,xsp) < feval(f,xs) )
                    x = xsp;
                    break;
                end
                xsm = xs - k*d(:,i);
                if( feval(f,xsm) < feval(f,xs) )
                    x = xsm;
                    break;
                end
            end
        end
    end