"The problem has inequality constraints. Create an instance of EqualityConstrainedModel" error when solving with ipopt preset in Debug mode

[traversaro]

I am trying to solve the example .nl files provided in https://github.com/cvanaret/Uno/tree/main/examples with uno_ampl with the ipopt preset, and they are both failing with:

uno_ampl: /home/traversaro/unows/Uno/uno/ingredients/subproblem/interior_point_methods/PrimalDualInteriorPointSubproblem.cpp:46: virtual void PrimalDualInteriorPointSubproblem::generate_initial_iterate(const NonlinearProblem&, Iterate&): Assertion `problem.has_inequality_constraints() && "The problem has inequality constraints. Create an instance of EqualityConstrainedModel"' failed.

However, if I try to comment out the assert in https://github.com/cvanaret/Uno/blob/e4a8fa7a21e9357c916d298b4f5cbb31a0f8d314/uno/ingredients/subproblem/interior_point_methods/PrimalDualInteriorPointSubproblem.cpp#L46, then the problems both get solved, and the solution is quite similar to the one found by ipopt, see for example for polak5.nl:

# Uno
(/home/traversaro/unows/env) traversaro@IITICUBLAP257:~/unows/Uno/build$ ./uno_ampl -preset ipopt -print_solution yes ../examples/polak5.nl
<...>
Uno (LS feasibility_restoration waechter_filter_method primal_dual_interior_point)
Wed Jun 21 16:31:43 2023
────────────────────────────────────────
Status:                                 Converged with feasible KKT point
Objective value:                        50
┌ Optimality stationarity residual:     8.458521e-09
│ Feasibility stationarity residual:    1
│ Constraint violation:                 8.4585e-09
│ Optimality complementarity residual:  1e-09
└ Feasibility complementarity residual: 8.454271e-06
┌ Infeasibility measure:                1.610706e-08
│ Optimality measure:                   50
└ Auxiliary measure:                    4.01609e-08
Primal solution:                        1.036611e-09 0.005779715 50
Constraint multipliers:                 -0.5 -0.5
Lower bound multipliers:                0 0 0
Upper bound multipliers:                0 0 0
Objective multiplier:                   1
CPU time:                               0.144922s
Iterations:                             32
Objective evaluations:                  33
Constraints evaluations:                34
Objective gradient evaluations:         34
Jacobian evaluations:                   34
Hessian evaluations:                    32
Number of subproblems solved:           32
memory_allocation_amount = 0

# Ipopt

(/home/traversaro/unows/env) traversaro@IITICUBLAP257:~/unows/Uno/build$ ipopt ../examples/polak5.nl

<...>
                                   (scaled)                 (unscaled)
Objective...............:   4.9999999991818186e+01    4.9999999991818186e+01
Dual infeasibility......:   8.4449709447653731e-09    8.4449709447653731e-09
Constraint violation....:   6.6267923873419930e-09    6.6267923873419930e-09
Variable bound violation:   0.0000000000000000e+00    0.0000000000000000e+00
Complementarity.........:   9.0909090909090941e-10    9.0909090909090941e-10
Overall NLP error.......:   8.4449709447653731e-09    8.4449709447653731e-09

Number of objective function evaluations             = 33
Number of objective gradient evaluations             = 33
Number of equality constraint evaluations            = 0
Number of inequality constraint evaluations          = 33
Number of equality constraint Jacobian evaluations   = 0
Number of inequality constraint Jacobian evaluations = 33
Number of Lagrangian Hessian evaluations             = 32
Total seconds in IPOPT                               = 0.025

EXIT: Optimal Solution Found.

Ipopt 3.14.12: Optimal Solution Found

[cvanaret]

Hi Silvio/@traversaro , Thanks for reporting the error. Of course, it should be not problem.has_inequality_constraints(). This was actually fixed in a subsequent commit (93cb0a2f0bbe7cf10e721254de487826ee1c5d28), so you just have to git pull. Best,

Charlie

[traversaro]

Thanks for the fast feedback @cvanaret !

This was actually fixed in a subsequent commit (93cb0a2), so you just have to git pull.

I am currently using the last commit (https://github.com/cvanaret/Uno/commit/e4a8fa7a21e9357c916d298b4f5cbb31a0f8d314), and I still see the problem.

I am not familiar with the codebase, but the commit you reference changed an assert in the PrimalDualInteriorPointSubproblem::solve method, while the assert I was referencing to is in the PrimalDualInteriorPointSubproblem::generate_initial_iterate method, and seems to be still there in the main branch: https://github.com/cvanaret/Uno/blob/main/uno/ingredients/subproblem/interior_point_methods/PrimalDualInteriorPointSubproblem.cpp#L46 .

[cvanaret]

Oh, thanks for catching that one. I overlooked the function name in your first message. It's now fixed in commit a1f89f7d77714126993fbd283bcfe312855f11d2.

[traversaro]

Thanks!