GEKKO Singular Matrix Problem with BPOPT and Solver Selection

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  1. I used MODES = 7 to sequentially solve a simulation problem with BPOPT solver. The solver can solve the first few problems but report the following error:
 *** WARNING MESSAGE FROM SUBROUTINE MA27BD  *** INFO(1) = 3

     MATRIX IS SINGULAR. RANK=  581

 Problem with linear solver, INFO:            3
  1. With solver=0, I can see the GEKKO has 6 different solvers. I wonder how can I specify a solver (like MINOS).
gekko
1 Answers

You can change solvers with m.options.SOLVER=1 for APOPT or m.options.SOLVER=3 for IPOPT. The other solvers aren't available for public use because they require a license.

The error message that you are receiving is because the solver could not find a search direction. I recommend including variable bounds such as lower bound of zero for some variables to prevent singular solutions.

If you'd like more specific help, please post minimal, verifiable code.

user_23669410
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