No feasible solution found when using intlinprog

I am using "intlinprog" to solve a system of linear equations. The "f" matrix is a 1x180 matrix. Can intlinprog process large matrices like this? I have 12 unknowns with 7 equality constraint equations.

[Ameer Hamza]

You said there are 12 unknowns. Shouldn't f be [1 x 12]?

[Steve Grikschat]

I'm not sure why you are using intlinprog for this. Are you restricting the solution of the system to be integer (or partly integer)?

Either way, I would agree with Ameer in that I'm unsure how you got a 180-element vector.

If the system is 7 equations with 12 unknowns, then intlinprog's Aeq input should be a 7x12 matrix.

Additionally, 180 variables or constraints is not too much for intlinprog.

Are you sure that there is a solution to the problem?

[Austin Brehm]

Very sorry, I meant to say 180 unknowns and 28 constraints. I made a mistake while creating the Aeq matrix and it now outputs one solution. Is there a way to check all answers matlab comes up with, not just the optimal point? Thank you very much.

[Ameer Hamza]

The Display property of intlinprog() is already set to 'iter', which mean it already displays the result of each iteration by default. I am not sure whether you will be able to access any more information than that but you can give this link a try: https://www.mathworks.com/help/matlab/math/output-functions.html#bsgpq6q-31

Answer 1

[Steve Grikschat]

If you are referring to intermediate feasible solutions you can use the built-in OutputFcn savemilpsolutions:

intlinprog OutputFcns

Just a warning: if there is no objective function for the problem (or it is all zero), then as soon as intlinprog finds any integer feasible solution, it will stop.