How to arrange the constraints shape to A matrix and b constants automatically ( Ax <= b)??
17 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Hi. I'm not good at MATLAB so please help me^^
I want to solve LP problem using "linprog",
so I have to make inequality constraints to A matrix and b constants. (Ax <= b)
And my inequality constraint's variables are mixed each other, so I have to arrange the constraints.
For example,
x1 + x2 <= x3 + x4 + 1 ; % constraint 1
X3 <= x1 + 10 ; % constraint 2
x2 + x4 <= 7 ; % constraint 3
In this situation, how can I make shape "Ax <= b" automatically??
It means I don't have to code one by one.
1 Kommentar
Sanush
am 20 Okt. 2021
Rearrange your constraint
Px1 <= Qx2 + c
(P - Q - c)*(x1', x2', 1)' <= 0
% for x1 + x2 <= x3 + x4 + 1
P = x1 + x2
Q = x3 + x4 + 1
% As Ax <= b
A = P - Q
b = zeros(size(A,1),1)
Akzeptierte Antwort
Matt J
am 2 Okt. 2021
Bearbeitet: Matt J
am 2 Okt. 2021
Using the problem-based solvers, you do not have to build things in matrix form, e.g.,
x=optimvar('x',4,'LowerBound',0,'UpperBound',20);
con(1)=x(1) + x(2) <= x(3) + x(4) + 1 ; % constraint 1
con(2)=x(3) <= x(1) + 10 ; % constraint 2
con(3)=x(2) + x(4) <= 7 ; % constraint 3
sol=solve( optimproblem('Objective',-sum(x),'Constraints',con) )
However, if you really must have the matrices, then you can use prob2matrices,
p=prob2matrices({x},'Constraints',con)
Weitere Antworten (1)
Chunru
am 2 Okt. 2021
% Let x = [x1; x2; x3; x4]
% x1 + x2 <= x3 + x4 + 1 ; % constraint 1
% => [1 1 -1 -1]*x <= 1
% X3 <= x1 + 10 ; % constraint 2
% => [-1 0 1 0]*x <= 10
% x2 + x4 <= 7 ; % constraint 3
% => [0 1 0 1]*x <=7
% Putting together
% [ 1 1 -1 -1] [ 1 ]
% |-1 0 1 0| * x <=|10 ]
% [ 0 1 0 1] [ 7 ]
%
% Therefore, you can specify A and b as follows
A = [1 1 -1 -1; -1 0 1 0; 0 1 0 1];
b = [1; 10; 7];
2 Kommentare
Siehe auch
Kategorien
Mehr zu General Physics finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!