BDSSCfg.txt

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# A txt description of a BlockSolverConfig for the subproblem of one Benders
# component, i.e., the linear program whose value function is being
# approximated, and whose duals ARE the Benders cuts.
#
# Two things are asked of the Solver beyond solving it, and only the second
# constrains how it is solved:
#
# - the duals of an optimal solution, which give the optimality cut: any
#   optimal dual solution does, basic or not, an interior-point one included;
#
# - the unbounded dual direction of an infeasible one, i.e., a Farkas
#   certificate, which gives the feasibility cut: it is a ray of the dual
#   polyhedron, hence any method can produce it, but the presolve cannot, it
#   detecting the infeasibility on the reduced problem and leaving no
#   certificate for the original one.
#
# With Gurobi nothing else is needed, the InfUnbdInfo parameter being set by
# GRBMILPSolver itself; the equivalent configurations are
#
#   CPXMILPSolver:   CPXPARAM_Preprocessing_Presolve 0
#   HiGHSMILPSolver: presolve off
#
# while SCIPMILPSolver has no Farkas certificate at all, its
# has_dual_direction() being not implemented yet: with it, only subproblems
# that are always feasible can be dealt with.
#
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BlockSolverConfig     # exact type of the Configuration object

0  # the BlockSolverConfig is not a "differential" one

1  # number of (the names of) Solver in this BlockSolverConfig

# now all the names of the Solver - - - - - - - - - - - - - - - - - - - - - -
GRBMILPSolver

1  # number of ComputeConfig in this BlockSolverConfig

# now all the ComputeConfig - - - - - - - - - - - - - - - - - - - - - - - - -
ComputeConfig # exact type of the ComputeConfig object

0  # f_diff == 0 ==> all non-provided parameters are set to the default value
   # f_diff == 1 ==> all non-provided parameters are not changed

5  # number of integer parameters

# now all the integer parameters
intLogVerb        0  # LogVerb, log verbosity of the MILPSolver
Threads           1  # one thread, so that the time is that of a sequential
                     # algorithm, as every other one here is
intRelaxIntVars   1  # solve the continuous (LP) relaxation
Method            1  # dual simplex: asked for reproducibility of the duals,
                     # any optimal ones giving a valid optimality cut
Presolve          0  # off, or an infeasible subproblem leaves no Farkas
                     # certificate and no feasibility cut can be generated

1  # number of double parameters

# now all the double parameters
dblRelAcc      1e-9  # relative accuracy required to solution

0  # number of string parameters

# now all the string parameters
# [none]

0  # number of vector-of-int parameters

# now all the vector-of-int parameters
# [none]

0  # number of vector-of-double parameters

# now all the vector-of-double parameters
# [none]

0  # number of vector-of-string parameters

# now all the vector-of-string parameters
# [none]

# pointer to the "extra" Configuration
*  # [none]

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