C++ Reference
C++ Reference: Linear solver
Detailed Description
The class for constraints of a Mathematical Programming (MP) model.
A constraint is represented as a linear equation or inequality.
Definition at line 1140 of file linear_solver.h.
Public Member Functions | |
const std::string & | name () const |
Returns the name of the constraint. More... | |
void | Clear () |
Clears all variables and coefficients. Does not clear the bounds. More... | |
void | SetCoefficient (const MPVariable *const var, double coeff) |
Sets the coefficient of the variable on the constraint. More... | |
double | GetCoefficient (const MPVariable *const var) const |
Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint). More... | |
const absl::flat_hash_map< const MPVariable *, double > & | terms () const |
Returns a map from variables to their coefficients in the constraint. More... | |
double | lb () const |
Returns the lower bound. More... | |
double | ub () const |
Returns the upper bound. More... | |
void | SetLB (double lb) |
Sets the lower bound. More... | |
void | SetUB (double ub) |
Sets the upper bound. More... | |
void | SetBounds (double lb, double ub) |
Sets both the lower and upper bounds. More... | |
bool | is_lazy () const |
Advanced usage: returns true if the constraint is "lazy" (see below). More... | |
void | set_is_lazy (bool laziness) |
Advanced usage: sets the constraint "laziness". More... | |
const MPVariable * | indicator_variable () const |
bool | indicator_value () const |
int | index () const |
Returns the index of the constraint in the MPSolver::constraints_. More... | |
double | dual_value () const |
Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems). More... | |
MPSolver::BasisStatus | basis_status () const |
Advanced usage: returns the basis status of the constraint. More... | |
Protected Member Functions | |
MPConstraint (int index, double lb, double ub, const std::string &name, MPSolverInterface *const interface_in) | |
void | set_dual_value (double dual_value) |
Constructor & Destructor Documentation
◆ MPConstraint()
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inlineprotected |
Definition at line 1247 of file linear_solver.h.
Member Function Documentation
◆ basis_status()
MPSolver::BasisStatus basis_status | ( | ) | const |
Advanced usage: returns the basis status of the constraint.
It is only available for continuous problems).
Note that if a constraint "linear_expression in [lb, ub]" is transformed into "linear_expression + slack = 0" with slack in [-ub, -lb], then this status is the same as the status of the slack variable with AT_UPPER_BOUND and AT_LOWER_BOUND swapped.
◆ Clear()
void Clear | ( | ) |
Clears all variables and coefficients. Does not clear the bounds.
◆ dual_value()
double dual_value | ( | ) | const |
Advanced usage: returns the dual value of the constraint in the current solution (only available for continuous problems).
◆ GetCoefficient()
double GetCoefficient | ( | const MPVariable *const | var | ) | const |
Gets the coefficient of a given variable on the constraint (which is 0 if the variable does not appear in the constraint).
◆ index()
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inline |
Returns the index of the constraint in the MPSolver::constraints_.
Definition at line 1208 of file linear_solver.h.
◆ indicator_value()
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inline |
Definition at line 1205 of file linear_solver.h.
◆ indicator_variable()
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inline |
Definition at line 1204 of file linear_solver.h.
◆ is_lazy()
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inline |
Advanced usage: returns true if the constraint is "lazy" (see below).
Definition at line 1187 of file linear_solver.h.
◆ lb()
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inline |
Returns the lower bound.
Definition at line 1172 of file linear_solver.h.
◆ name()
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inline |
Returns the name of the constraint.
Definition at line 1143 of file linear_solver.h.
◆ set_dual_value()
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inlineprotected |
Definition at line 1259 of file linear_solver.h.
◆ set_is_lazy()
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inline |
Advanced usage: sets the constraint "laziness".
This is only supported for SCIP and has no effect on other solvers.
When laziness is true, the constraint is only considered by the Linear Programming solver if its current solution violates the constraint. In this case, the constraint is definitively added to the problem. This may be useful in some MIP problems, and may have a dramatic impact on performance.
For more info see: http://tinyurl.com/lazy-constraints.
Definition at line 1202 of file linear_solver.h.
◆ SetBounds()
void SetBounds | ( | double | lb, |
double | ub | ||
) |
Sets both the lower and upper bounds.
◆ SetCoefficient()
void SetCoefficient | ( | const MPVariable *const | var, |
double | coeff | ||
) |
Sets the coefficient of the variable on the constraint.
If the variable does not belong to the solver, the function just returns, or crashes in non-opt mode.
◆ SetLB()
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inline |
Sets the lower bound.
Definition at line 1178 of file linear_solver.h.
◆ SetUB()
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inline |
Sets the upper bound.
Definition at line 1181 of file linear_solver.h.
◆ terms()
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inline |
Returns a map from variables to their coefficients in the constraint.
If a variable is not present in the map, then its coefficient is zero.
Definition at line 1167 of file linear_solver.h.
◆ ub()
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inline |
Returns the upper bound.
Definition at line 1175 of file linear_solver.h.
The documentation for this class was generated from the following file: