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This class is an abstract base class for LP solvers. This class provides a full interface for set and modify an LP problem, solve it and retrieve the solution. You can use one of the descendants as a concrete implementation, or the Lp default LP solver. However, if you would like to handle LP solvers as reference or pointer in a generic way, you can use this class directly.
#include <lemon/lp_base.h>
Inheritance diagram for LpSolver:Public Types | |
| enum | ProblemType { UNDEFINED = 0, INFEASIBLE = 1, FEASIBLE = 2, OPTIMAL = 3, UNBOUNDED = 4 } |
| The problem types for primal and dual problems. More... | |
| enum | VarStatus { BASIC, FREE, LOWER, UPPER, FIXED } |
| The basis status of variables. More... | |
| Public Types inherited from LpBase | |
| enum | SolveExitStatus { SOLVED = 0, UNSOLVED = 1 } |
| Possible outcomes of an LP solving procedure. More... | |
| enum | Sense { MIN, MAX } |
| Direction of the optimization. More... | |
| enum | MessageLevel { MESSAGE_NOTHING, MESSAGE_ERROR, MESSAGE_WARNING, MESSAGE_NORMAL, MESSAGE_VERBOSE } |
Enum for messageLevel() parameter. More... | |
| typedef double | Value |
| The floating point type used by the solver. | |
Public Member Functions | |
| virtual LpSolver * | newSolver () const =0 |
| Allocate a new LP problem instance. | |
| virtual LpSolver * | cloneSolver () const =0 |
| Make a copy of the LP problem. | |
Solve the LP | |
| SolveExitStatus | solve () |
Obtain the Solution | |
| ProblemType | primalType () const |
| The type of the primal problem. | |
| ProblemType | dualType () const |
| The type of the dual problem. | |
| Value | primal (Col c) const |
| Return the primal value of the column. More... | |
| Value | primal (const Expr &e) const |
| Return the primal value of the expression. More... | |
| Value | primalRay (Col c) const |
| Returns a component of the primal ray. More... | |
| Value | dual (Row r) const |
| Return the dual value of the row. More... | |
| Value | dual (const DualExpr &e) const |
| Return the dual value of the dual expression. More... | |
| Value | dualRay (Row r) const |
| Returns a component of the dual ray. More... | |
| VarStatus | colStatus (Col c) const |
| Return the basis status of the column. More... | |
| VarStatus | rowStatus (Row r) const |
| Return the basis status of the row. More... | |
| Value | primal () const |
| The value of the objective function. More... | |
| Public Member Functions inherited from LpBase | |
| virtual | ~LpBase () |
| Virtual destructor. | |
| const char * | solverName () const |
| Gives back the name of the solver. | |
| Col | addCol () |
| Add a new empty column (i.e a new variable) to the LP. | |
| template<class T > | |
| int | addColSet (T &t) |
| Adds several new columns (i.e variables) at once. More... | |
| void | col (Col c, const DualExpr &e) |
| Set a column (i.e a dual constraint) of the LP. More... | |
| DualExpr | col (Col c) const |
| Get a column (i.e a dual constraint) of the LP. More... | |
| Col | addCol (const DualExpr &e, Value o=0) |
| Add a new column to the LP. More... | |
| Row | addRow () |
| Add a new empty row (i.e a new constraint) to the LP. More... | |
| template<class T > | |
| int | addRowSet (T &t) |
| Add several new rows (i.e constraints) at once. More... | |
| void | row (Row r, Value l, const Expr &e, Value u) |
| Set a row (i.e a constraint) of the LP. More... | |
| void | row (Row r, const Constr &c) |
| Set a row (i.e a constraint) of the LP. More... | |
| Expr | row (Row r) const |
| Get a row (i.e a constraint) of the LP. More... | |
| Row | addRow (Value l, const Expr &e, Value u) |
| Add a new row (i.e a new constraint) to the LP. More... | |
| Row | addRow (const Constr &c) |
| Add a new row (i.e a new constraint) to the LP. More... | |
| void | erase (Col c) |
| Erase a column (i.e a variable) from the LP. More... | |
| void | erase (Row r) |
| Erase a row (i.e a constraint) from the LP. More... | |
| std::string | colName (Col c) const |
| Get the name of a column. More... | |
| void | colName (Col c, const std::string &name) |
| Set the name of a column. More... | |
| Col | colByName (const std::string &name) const |
| Get the column by its name. More... | |
| std::string | rowName (Row r) const |
| Get the name of a row. More... | |
| void | rowName (Row r, const std::string &name) |
| Set the name of a row. More... | |
| Row | rowByName (const std::string &name) const |
| Get the row by its name. More... | |
| void | coeff (Row r, Col c, Value val) |
| Set an element of the coefficient matrix of the LP. More... | |
| Value | coeff (Row r, Col c) const |
| Get an element of the coefficient matrix of the LP. More... | |
| void | colLowerBound (Col c, Value value) |
| Set the lower bound of a column (i.e a variable) More... | |
| Value | colLowerBound (Col c) const |
| Get the lower bound of a column (i.e a variable) More... | |
| template<class T > | |
| void | colLowerBound (T &t, Value value) |
| Set the lower bound of several columns (i.e variables) at once. More... | |
| void | colUpperBound (Col c, Value value) |
| Set the upper bound of a column (i.e a variable) More... | |
| Value | colUpperBound (Col c) const |
| Get the upper bound of a column (i.e a variable) More... | |
| template<class T > | |
| void | colUpperBound (T &t, Value value) |
| Set the upper bound of several columns (i.e variables) at once. More... | |
| void | colBounds (Col c, Value lower, Value upper) |
| Set the lower and the upper bounds of a column (i.e a variable) More... | |
| template<class T > | |
| void | colBounds (T &t, Value lower, Value upper) |
| Set the lower and the upper bound of several columns (i.e variables) at once. More... | |
| void | rowLowerBound (Row r, Value value) |
| Set the lower bound of a row (i.e a constraint) More... | |
| Value | rowLowerBound (Row r) const |
| Get the lower bound of a row (i.e a constraint) More... | |
| void | rowUpperBound (Row r, Value value) |
| Set the upper bound of a row (i.e a constraint) More... | |
| Value | rowUpperBound (Row r) const |
| Get the upper bound of a row (i.e a constraint) More... | |
| void | objCoeff (Col c, Value v) |
| Set an element of the objective function. | |
| Value | objCoeff (Col c) const |
| Get an element of the objective function. | |
| void | obj (const Expr &e) |
| Set the objective function. More... | |
| Expr | obj () const |
| Get the objective function. More... | |
| void | sense (Sense sense) |
| Set the direction of optimization. | |
| Sense | sense () const |
| Query the direction of the optimization. | |
| void | max () |
| Set the sense to maximization. | |
| void | min () |
| Set the sense to maximization. | |
| void | clear () |
| Clear the problem. | |
| void | messageLevel (MessageLevel level) |
| Set the message level of the solver. | |
| void | write (std::string file, std::string format="MPS") const |
| Write the problem to a file in the given format. More... | |
Additional Inherited Members | |
| Static Public Member Functions inherited from LpBase | |
| static int | id (const Col &col) |
| Returns the ID of the column. | |
| static Col | colFromId (int id) |
| Returns the column with the given ID. More... | |
| static int | id (const Row &row) |
| Returns the ID of the row. | |
| static Row | rowFromId (int id) |
| Returns the row with the given ID. More... | |
| Static Public Attributes inherited from LpBase | |
| static const Value | INF |
| The infinity constant. | |
| static const Value | NaN |
| The not a number constant. | |
| enum ProblemType |
| enum VarStatus |
|
inline |
Solve the LP problem at hand
Return the primal value of the column.
Return the primal value of the expression, i.e. the dot product of the primal solution and the expression.
The primal ray is solution of the modified primal problem, where we change each finite bound to 0, and we looking for a negative objective value in case of minimization, and positive objective value for maximization. If there is such solution, that proofs the unsolvability of the dual problem, and if a feasible primal solution exists, then the unboundness of primal problem.
Return the dual value of the row.
Return the dual value of the dual expression, i.e. the dot product of the dual solution and the dual expression.
The dual ray is solution of the modified primal problem, where we change each finite bound to 0 (i.e. the objective function coefficients in the primal problem), and we looking for a ositive objective value. If there is such solution, that proofs the unsolvability of the primal problem, and if a feasible dual solution exists, then the unboundness of dual problem.
1.8.5
