How to use code constraint file for fmincon function

I am a beginner, i am trying to use the fmincon function to optimize the design of a separator vessel,in the constraint file i have a variable (Urg) which is calculated earlier in the program the constraint is (c4=Urg*(x(1)-Lll)-x(2)*Uog; when i run the program it gives me error Undefined function or variable 'Urg'.Pleas how to solve this problem and when i call Urg it gives its calculated value.

Answer 1

[Matt J]

We can only assume (especially without seeing code) that you accidentally cleared Urg.

Answer 2

[Alan Weiss]

It is possible that you calculate the value Urg in one function and then try to use it in another. There is a documented way to share a result between the objective function and nonlinear constraint functions.

But without further details I am just guessing.

Alan Weiss

MATLAB mathematical toolbox documentation