How do i plot the function as a mesh in the constraint area only?

8 views (last 30 days)
Given is the following conditions:
Using linprog()
Maximize: f= 30*X1 + 10*X2;
subject to : 6*X1 + 3*X2 <= 40;
3*X1 - X2<=0 ;
X1 + 0.25*X2 <= 4;
X1>=0
X2>=0
Display the plot
-the function as a mesh in the constraint area only (using mesh())
below is my approach ...please correct me.
f = [-30 -10];
A=[6 3;3 -1;1 0.25];
b=[40 0 4];
lb = zeros(2,1);
ub = [];
Aeq = [];
beq = [];
tic
options = optimoptions('linprog','Algorithm','dual-simplex','Display','iter');
[sol,fval,exitflag,output] = linprog(f,A,b,Aeq,beq,lb,ub,options);
LP preprocessing removed 0 inequalities, 0 equalities, 0 variables, and added 0 non-zero elements. Iter Time Fval Primal Infeas Dual Infeas 0 0.037 0.000000e+00 0.000000e+00 1.335997e+01 2 0.06 -1.600000e+02 2.057442e+00 0.000000e+00 3 0.06 -1.466667e+02 0.000000e+00 0.000000e+00 Optimal solution found.
toc
Elapsed time is 1.673879 seconds.
[X1 X2]=meshgrid(0:0.2:50,0:0.2:50);
cons1= 6*X1 + 3*X2 <= 40;
cons2= 3*X1 - X2<=0 ;
cons3= X1 + 0.25*X2 <= 4;
X1(~cons1)= NaN;
X1(~cons2)= NaN;
X1(~cons3)= NaN;
X2(~cons1)= NaN;
X2(~cons2)= NaN;
X2(~cons3)= NaN;
f= 30*X1 + 10*X2;
mesh(X1,X2,f);

Accepted Answer

yanqi liu
yanqi liu on 22 Nov 2021
sir,which is the question?
clc; clear all; close all;
f = [-30 -10];
A=[6 3;3 -1;1 0.25];
b=[40 0 4];
lb = zeros(2,1);
ub = [];
Aeq = [];
beq = [];
tic
options = optimoptions('linprog','Algorithm','dual-simplex','Display','iter');
[sol,fval,exitflag,output] = linprog(f,A,b,Aeq,beq,lb,ub,options);
LP preprocessing removed 0 inequalities, 0 equalities, 0 variables, and added 0 non-zero elements. Iter Time Fval Primal Infeas Dual Infeas 0 0.098 0.000000e+00 0.000000e+00 1.335997e+01 2 0.136 -1.600000e+02 2.057442e+00 0.000000e+00 3 0.137 -1.466667e+02 0.000000e+00 0.000000e+00 Optimal solution found.
toc
Elapsed time is 2.145769 seconds.
[X1, X2]=meshgrid(0:0.1:20,0:0.1:20);
cons1= 6*X1 + 3*X2 <= 40;
cons2= 3*X1 - X2<=0 ;
cons3= X1 + 0.25*X2 <= 4;
X1(~(cons1&cons2&cons1))= NaN;
X2(~(cons1&cons2&cons1))= NaN;
f= 30*X1 + 10*X2;
mesh(X1,X2,-f);
xlabel('X1')
ylabel('X2')
zlabel('f')
hold on;
plot3(sol(1),sol(2),fval,'ro','MarkerFaceColor', 'r');

More Answers (0)

Categories

Find more on 2-D and 3-D Plots in Help Center and File Exchange

Products


Release

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!