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Add support for indicator constraints in MPSolver #132
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Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
Signed-off-by: Peter Mitri <peter.mitri@rte-france.com>
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What happens if indicator_variable
is not a binary variable ?
/// Creates a named indicator constraint with given bounds and given | ||
/// indicator variable. |
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/// Creates a named indicator constraint with given bounds and given | |
/// indicator variable. | |
/// Creates a named indicator constraint with given bounds and given | |
/// indicator variable. | |
/// The constraint is active if and only if *indicator_variable has value indicator_value | |
/// (Only available for MILP problems) |
MPConstraint* MPSolver::MakeIndicatorConstraint( | ||
double lb, double ub, const std::string& name, |
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- This method should fail if the solver doesn't support integer variables
- You can call
MPVariable::integer
to check it's an integer variable on the indicator variable, and possibly test it's bounds (0 & 1).
const int constraint_index = NumConstraints(); | ||
MPConstraint* const constraint = | ||
new MPConstraint(constraint_index, lb, ub, name, interface_.get()); | ||
// TODO: check that variable is boolean? |
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👍🏻
} | ||
constraints_.push_back(constraint); | ||
constraint_is_extracted_.push_back(false); | ||
interface_->AddIndicatorConstraint(constraint); |
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Check the return value ?
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Log improvement ideas
constraint->indicator_variable_ = indicator_variable; | ||
constraint->indicator_value_ = indicator_value; | ||
if (!interface_->AddIndicatorConstraint(constraint)) { | ||
LOG(ERROR) << "Solver doesn't support indicator constraints"; |
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I don't think it's necessary to display a log message here, it's already done in the base version of AddIndicatorConstraint
(linear_solver.cc)
virtual bool AddIndicatorConstraint(MPConstraint* const /*ct*/) {
LOG(ERROR) << "Solver doesn't support indicator constraints.";
return false;
}
It would be displayed twice. Not terrible, but not great either.
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OK, but then for interfaces that can sometimes handle indicator constraints, sometimes not (for example an interface that can handle MIP or LP problems), we'll have to log the issue before returning "false"
Co-authored-by: Florian Omnès <florian.omnes@rte-france.com>
MPConstraint* MPSolver::MakeIndicatorConstraint( | ||
double lb, double ub, const std::string& name, | ||
const MPVariable* indicator_variable, bool indicator_value) { | ||
if (!indicator_variable->integer() || indicator_variable->lb() != 0 || |
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To be consistent with e.g MPObjective::SetCoefficient
and MPConstraint::SetCoefficient
, you'd need the following lines
Although the 2nd line is currently included in the 1st.
DLOG_IF(DFATAL, !interface_->solver_->OwnsVariable(indicator_variable)) << indicator_variable;
if (indicator_variable == nullptr) return nullptr;
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good catch!
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