Linear programming (having upper and lower limit)

 I need help to write code for linear programming like below.

Minimize Z=5*x1+2*x2-3

Subject to x1+2x2=6 -1<x1<2 0<x2<1

[Andrew Newell]

Google "linear programming MATLAB"

[Mohammad Yunus Ali]

I wrote a code like below. but not running

clc

clear all

% minimizing f(x) = –5x1 – 4x2 –6x3, subject to

% x1 – x2 + x3 ? 20

% 3x1 + 2x2 + 4x3 ? 42

% 3x1 + 2x2 ? 30

% 0 ? x1, 0 ? x2, 0 ? x3.

f = [-5; -4; -6];

A = [1 -1 1

3 2 4

3 2 0];

b = [20; 42; 30];

lb = zeros(3,1);

Aeq=[];

beq=[];

x = linprog(f,A,b,Aeq,beq,lb);

[Andrew Newell]

Assuming the question marks represent <=, this code works fine on my machine. Do you have the Optimization Toolbox?

Answer 1

[Andrew Newell]

I assume that the above code is not working because you don't have the Optimization Toolbox. You can download Revised Simplex Method from the File Exchange and use fairly similar code:

clc
clear all

% minimizing f(x) = –5x1 – 4x2 –6x3, subject to
%
% x1 – x2 + x3 <= 20
% 3x1 + 2x2 + 4x3 <= 42
% 3x1 + 2x2 <= 30
% 0 <= x1, 0 <= x2, 0 <= x3.

f = [-5 -4 -6];
A = [1 -1 1
3 2 4
3 2 0];
b = [20 42 30];
inq = [-1 -1 -1];
minimize = 1;

revised(f,b,A,inq,minimize)

This gives some diagnostic code followed by

The optimum solution is:
x1 = 0
x2 = 15
x3 = 3

[Mohammad Yunus Ali]

Thanks for your reply. But the code is not running. Its showing error. like below:

??? Undefined function or method 'revised' for input arguments of type 'double'.

Error in ==> linpr at 9

revised(f,b,A,inq,minimize)

could you pls write a complete code for me.

[Andrew Newell]

Did you download the code and add the folder containing it to your path?