Matlab源码 基于BF共轭梯度法求解无约束非线性问题matlab程序.zip

function [LB, UB] = forwardback(xinit,dxinit,objfun) %% Input x0 = xinit; dx = dxinit; flag = 0; %% step1 f0 = objfun(x0); %% step2 x1 = x0 + dx; f1 = objfun(x1); if f1 <= f0 %% step3 while dx<=1e8 && flag == 0 dx = 2*dx; x2 = x1+dx; f2 = objfun(x2); if f1 <= f2 a = x0; c = x1; b = x2; flag = 1; else %% step4 x0 = x1; x1 = x2; f0 = f1; f1 = f2; end end else %% step5 while dx<=1e8 && flag == 0 dx = 2*dx; x2 = x0-dx; f2 = objfun(x2); if f0 <= f2 a = x2; c = x0; b = x1; flag = 1; else %% step6 x1 = x0; x0 = x2; f1 = f0; f0 = f2; end end end %% Output if flag == 0 % fprintf('Fail!\n') LB = xinit; UB = xinit+dx; else % fprintf('Success!\n a_left=%3.1f, c_middle=%3.1f, b_right=%3.1f.\n',a,c,b); LB = a; UB = b; end end