Infeasible subset when using computeIIS()
回答済みI am solving an optimization model and I fixed some decision variables by constraints, however the model then becomes infeasible. The output of computeIIS() is show as follows:
\ Model DAA optimization_copy
\ LP format - for model browsing. Use MPS format to capture full model detail.
Maximize
Subject To
R12: r2_dispatch_radius = 5
R13: r1_dispatch_radius = 9.9
qc0: [ - r1_dispatch_radius ^2 + r2_dispatch_radius ^2
- 6.558 r2_dispatch_radius * z_cos_2 ] = -10.751841
Bounds
r1_dispatch_radius free
r2_dispatch_radius free
z_cos_2 >= -1
End
decision variables are: r1_dispatch_radius, r2_dispatch_radius and -1 <= z_cos_2 <= 1. May I know why this is infeasible? Thanks!
-
正式なコメント
-
Gurobi Staff
This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support. -
-
-
Hi Jingfeng,
If you solve the quadratic constraint for \(\texttt{z}\), you see that this is in fact infeasible with the condition of \(\texttt{z} \geq -1\):
\[
\begin{aligned}
- r_1^2 + r_2^2 - 6.558 \cdot r_2 \cdot z &= -10.751841 \\
z &= \frac{- r_1^2 + r_2^2 + 10.751841}{6.558 \cdot r_2} \\
z &= -1.89869347362
\end{aligned}
\]Cheers,
Matthias0 -
-
Hi Matthias,
Thanks for pointing the error. I have another question when I am modeling the optimization with Python. I have a Piecewise Function (nonlinear) in the model, for example, I would like to calculate the overlap area of two circles A and B. The formula is:
Do you know how to add this into the constraints? It seems like it need if it satisfy a condition, then the model can add set of variables and constraints. I have no idea how to implement this. Thanks a lot!
0 -
-
-
Answered in Conditional piecewise constraints modeling in Gurobi.
0 -
投稿コメントは受け付けていません。
コメント
4件のコメント