A class that implements the LpSolver interface using Z3. More...

#include <Z3LpSolver.h>

Inheritance diagram for storm::solver::Z3LpSolver< ValueType, RawMode >:

Collaboration diagram for storm::solver::Z3LpSolver< ValueType, RawMode >:

Public Types
using	VariableType = typename LpSolver< ValueType, RawMode >::VariableType

using	Variable = typename LpSolver< ValueType, RawMode >::Variable

using	Constant = typename LpSolver< ValueType, RawMode >::Constant

using	Constraint = typename LpSolver< ValueType, RawMode >::Constraint

Public Types inherited from storm::solver::LpSolver< ValueType, RawMode >
enum class	VariableType { Continuous , Integer , Binary }
	Enumerates the different types of variables. More...

using	Variable = std::conditional_t< RawMode, typename RawLpConstraint< ValueType >::VariableIndexType, storm::expressions::Variable >

using	Constant = std::conditional_t< RawMode, ValueType, storm::expressions::Expression >

using	Constraint = std::conditional_t< RawMode, RawLpConstraint< ValueType >, storm::expressions::Expression >

Public Member Functions
	Z3LpSolver (std::string const &name, OptimizationDirection const &optDir)
	Constructs a solver with the given name and optimization direction.

	Z3LpSolver (std::string const &name)
	Constructs a solver with the given name.

	Z3LpSolver (OptimizationDirection const &optDir)
	Constructs a solver without a name and the given optimization direction.

	Z3LpSolver ()
	Constructs a solver without a name.

virtual	~Z3LpSolver ()
	Destructs a solver by freeing the pointers to Z3's structures.

virtual Variable	addVariable (std::string const &name, VariableType const &type, std::optional< ValueType > const &lowerBound=std::nullopt, std::optional< ValueType > const &upperBound=std::nullopt, ValueType objectiveFunctionCoefficient=0) override
	Registers a variable of the given type.

virtual void	update () const override
	Updates the model to make the variables that have been declared since the last call to `update` usable.

virtual void	addConstraint (std::string const &name, Constraint const &constraint) override
	Adds a the given constraint to the LP problem.

virtual void	addIndicatorConstraint (std::string const &name, Variable indicatorVariable, bool indicatorValue, Constraint const &constraint) override
	Adds the given indicator constraint to the LP problem: "If indicatorVariable == indicatorValue, then constraint".

virtual void	optimize () const override
	Optimizes the LP problem previously constructed.

virtual bool	isInfeasible () const override
	Retrieves whether the model was found to be infeasible.

virtual bool	isUnbounded () const override
	Retrieves whether the model was found to be infeasible.

virtual bool	isOptimal () const override
	Retrieves whether the model was found to be optimal, i.e.

virtual ValueType	getContinuousValue (Variable const &variable) const override
	Retrieves the value of the continuous variable with the given name.

virtual int_fast64_t	getIntegerValue (Variable const &variable) const override
	Retrieves the value of the integer variable with the given name.

virtual bool	getBinaryValue (Variable const &variable) const override
	Retrieves the value of the binary variable with the given name.

virtual ValueType	getObjectiveValue () const override
	Retrieves the value of the objective function.

virtual void	writeModelToFile (std::string const &filename) const override
	Writes the current LP problem to the given file.

virtual void	push () override
	Pushes a backtracking point on the solver's stack.

virtual void	pop () override
	Pops a backtracking point from the solver's stack.

virtual void	setMaximalMILPGap (ValueType const &gap, bool relative) override
	Specifies the maximum difference between lower- and upper objective bounds that triggers termination.

virtual ValueType	getMILPGap (bool relative) const override
	Returns the obtained gap after a call to optimize()

Public Member Functions inherited from storm::solver::LpSolver< ValueType, RawMode >
	LpSolver ()
	Creates an empty LP solver.

	LpSolver (OptimizationDirection const &optDir)
	Creates an empty LP solver with the given model sense.

virtual	~LpSolver ()=default

Variable	addBoundedContinuousVariable (std::string const &name, ValueType lowerBound, ValueType upperBound, ValueType objectiveFunctionCoefficient=0)
	Registers an upper- and lower-bounded continuous variable, i.e.

Variable	addLowerBoundedContinuousVariable (std::string const &name, ValueType lowerBound, ValueType objectiveFunctionCoefficient=0)
	Registers a lower-bounded continuous variable, i.e.

Variable	addUpperBoundedContinuousVariable (std::string const &name, ValueType upperBound, ValueType objectiveFunctionCoefficient=0)
	Registers an upper-bounded continuous variable, i.e.

Variable	addUnboundedContinuousVariable (std::string const &name, ValueType objectiveFunctionCoefficient=0)
	Registers a unbounded continuous variable, i.e.

Variable	addContinuousVariable (std::string const &name, std::optional< ValueType > const &lowerBound=std::nullopt, std::optional< ValueType > const &upperBound=std::nullopt, ValueType objectiveFunctionCoefficient=0)
	Registers a continuous variable, i.e.

Variable	addBoundedIntegerVariable (std::string const &name, ValueType lowerBound, ValueType upperBound, ValueType objectiveFunctionCoefficient=0)
	Registers an upper- and lower-bounded integer variable, i.e.

Variable	addLowerBoundedIntegerVariable (std::string const &name, ValueType lowerBound, ValueType objectiveFunctionCoefficient=0)
	Registers a lower-bounded integer variable, i.e.

Variable	addUpperBoundedIntegerVariable (std::string const &name, ValueType upperBound, ValueType objectiveFunctionCoefficient=0)
	Registers an upper-bounded integer variable, i.e.

Variable	addUnboundedIntegerVariable (std::string const &name, ValueType objectiveFunctionCoefficient=0)
	Registers an unbounded integer variable, i.e.

Variable	addIntegerVariable (std::string const &name, std::optional< ValueType > const &lowerBound=std::nullopt, std::optional< ValueType > const &upperBound=std::nullopt, ValueType objectiveFunctionCoefficient=0)
	Registers an integer variable, i.e.

Variable	addBinaryVariable (std::string const &name, ValueType objectiveFunctionCoefficient=0)
	Registers a boolean variable, i.e.

Constant	getConstant (ValueType value) const
	Retrieves an expression that characterizes the given constant value.

void	setOptimizationDirection (OptimizationDirection const &optimizationDirection)
	Sets whether the objective function of this model is to be minimized or maximized.

OptimizationDirection	getOptimizationDirection () const
	Retrieves whether the objective function of this model is to be minimized or maximized.

storm::expressions::ExpressionManager const &	getManager () const
	Retrieves the manager for the variables created for this solver.

Additional Inherited Members
Protected Member Functions inherited from storm::solver::LpSolver< ValueType, RawMode >
storm::expressions::Variable	declareOrGetExpressionVariable (std::string const &name, VariableType const &type)

Protected Attributes inherited from storm::solver::LpSolver< ValueType, RawMode >
std::shared_ptr< storm::expressions::ExpressionManager >	manager

bool	currentModelHasBeenOptimized

Detailed Description

template<typename ValueType, bool RawMode = false>
class storm::solver::Z3LpSolver< ValueType, RawMode >

A class that implements the LpSolver interface using Z3.

Note: There is no benefit of using this solver in raw mode as it deals with storm::expressions anyway

Definition at line 24 of file Z3LpSolver.h.

Member Typedef Documentation

◆ Constant

template<typename ValueType , bool RawMode = false>

using storm::solver::Z3LpSolver< ValueType, RawMode >::Constant = typename LpSolver<ValueType, RawMode>::Constant

Definition at line 28 of file Z3LpSolver.h.

◆ Constraint

template<typename ValueType , bool RawMode = false>

using storm::solver::Z3LpSolver< ValueType, RawMode >::Constraint = typename LpSolver<ValueType, RawMode>::Constraint

Definition at line 29 of file Z3LpSolver.h.

◆ Variable

template<typename ValueType , bool RawMode = false>

using storm::solver::Z3LpSolver< ValueType, RawMode >::Variable = typename LpSolver<ValueType, RawMode>::Variable

Definition at line 27 of file Z3LpSolver.h.

◆ VariableType

template<typename ValueType , bool RawMode = false>

using storm::solver::Z3LpSolver< ValueType, RawMode >::VariableType = typename LpSolver<ValueType, RawMode>::VariableType

Definition at line 26 of file Z3LpSolver.h.

Constructor & Destructor Documentation

◆ Z3LpSolver() [1/4]

template<typename ValueType , bool RawMode>

storm::solver::Z3LpSolver< ValueType, RawMode >::Z3LpSolver	(	std::string const &	name,
		OptimizationDirection const &	optDir
	)

Constructs a solver with the given name and optimization direction.

Parameters

name	The name of the LP problem.
optDir	A value indicating whether the value of the objective function is to be minimized or maximized.

Definition at line 315 of file Z3LpSolver.cpp.

◆ Z3LpSolver() [2/4]

template<typename ValueType , bool RawMode>

storm::solver::Z3LpSolver< ValueType, RawMode >::Z3LpSolver ( std::string const & name )

Constructs a solver with the given name.

By default the objective function is assumed to be minimized, but this may be altered later using a call to setOptimizationDirection.

Parameters

name	The name of the LP problem.

Definition at line 321 of file Z3LpSolver.cpp.

◆ Z3LpSolver() [3/4]

template<typename ValueType , bool RawMode>

storm::solver::Z3LpSolver< ValueType, RawMode >::Z3LpSolver ( OptimizationDirection const & optDir )

Constructs a solver without a name and the given optimization direction.

Parameters

optDir A value indicating whether the value of the objective function is to be minimized or maximized.

Definition at line 327 of file Z3LpSolver.cpp.

◆ Z3LpSolver() [4/4]

template<typename ValueType , bool RawMode>

storm::solver::Z3LpSolver< ValueType, RawMode >::Z3LpSolver ( )

Constructs a solver without a name.

By default the objective function is assumed to be minimized, but this may be altered later using a call to setModelSense.

Definition at line 333 of file Z3LpSolver.cpp.

◆ ~Z3LpSolver()

template<typename ValueType , bool RawMode>

storm::solver::Z3LpSolver< ValueType, RawMode >::~Z3LpSolver ( )

virtual

Destructs a solver by freeing the pointers to Z3's structures.

Definition at line 339 of file Z3LpSolver.cpp.

Member Function Documentation

◆ addConstraint()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::addConstraint	(	std::string const &	name,
		Constraint const &	constraint
	)

overridevirtual

Adds a the given constraint to the LP problem.

Parameters

name	The name of the constraint. If empty, the constraint has no name.
constraint	An expression that represents the constraint. The given constraint must be a linear (in)equality over the registered variables.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 356 of file Z3LpSolver.cpp.

◆ addIndicatorConstraint()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::addIndicatorConstraint	(	std::string const &	name,
		Variable	indicatorVariable,
		bool	indicatorValue,
		Constraint const &	constraint
	)

overridevirtual

Adds the given indicator constraint to the LP problem: "If indicatorVariable == indicatorValue, then constraint".

Parameters

name	The name of the constraint. If empty, the constraint has no name.
indicatorVariable	must be a registered binary
indicatorValue
constraint	An expression that represents the constraint. The given constraint must be a linear (in)equality over the registered variables.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 362 of file Z3LpSolver.cpp.

◆ addVariable()

template<typename ValueType , bool RawMode>

Z3LpSolver< ValueType, RawMode >::Variable storm::solver::Z3LpSolver< ValueType, RawMode >::addVariable	(	std::string const &	name,
		VariableType const &	type,
		std::optional< ValueType > const &	lowerBound = `std::nullopt`,
		std::optional< ValueType > const &	upperBound = `std::nullopt`,
		ValueType	objectiveFunctionCoefficient = `0`
	)

overridevirtual

Registers a variable of the given type.

Note: In RawMode this returns a variable index. Variable indices are assigned consecutively starting at 0, i.e. the n'th variable has index (n-1).

Parameters

name	The name of the variable.
type	The type of the variable
lowerBound	The optional lower bound
upperBound	The optional upper bound
objectiveFunctionCoefficient	The coefficient with which the variable appears in the objective function. If omitted (or set to zero), the variable is irrelevant for the objective value.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 342 of file Z3LpSolver.cpp.

◆ getBinaryValue()

template<typename ValueType , bool RawMode>

bool storm::solver::Z3LpSolver< ValueType, RawMode >::getBinaryValue ( Variable const & variable ) const

overridevirtual

Retrieves the value of the binary variable with the given name.

Note that this may only be called, if the model was found to be optimal, i.e. iff isOptimal() returns true.

Parameters

variable The variable whose integer value (in the optimal solution) to retrieve.

Returns: The value of the binary variable in the optimal solution.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 410 of file Z3LpSolver.cpp.

◆ getContinuousValue()

template<typename ValueType , bool RawMode>

ValueType storm::solver::Z3LpSolver< ValueType, RawMode >::getContinuousValue ( Variable const & variable ) const

overridevirtual

Retrieves the value of the continuous variable with the given name.

Note that this may only be called, if the model was found to be optimal, i.e. iff isOptimal() returns true.

Parameters

variable The variable whose integer value (in the optimal solution) to retrieve.

Returns: The value of the continuous variable in the optimal solution.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 398 of file Z3LpSolver.cpp.

◆ getIntegerValue()

template<typename ValueType , bool RawMode>

int_fast64_t storm::solver::Z3LpSolver< ValueType, RawMode >::getIntegerValue ( Variable const & variable ) const

overridevirtual

Retrieves the value of the integer variable with the given name.

Note that this may only be called, if the model was found to be optimal, i.e. iff isOptimal() returns true.

Parameters

variable The variable whose integer value (in the optimal solution) to retrieve.

Returns: The value of the integer variable in the optimal solution.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 404 of file Z3LpSolver.cpp.

◆ getMILPGap()

template<typename ValueType , bool RawMode>

ValueType storm::solver::Z3LpSolver< ValueType, RawMode >::getMILPGap ( bool relative ) const

overridevirtual

Returns the obtained gap after a call to optimize()

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 446 of file Z3LpSolver.cpp.

◆ getObjectiveValue()

template<typename ValueType , bool RawMode>

ValueType storm::solver::Z3LpSolver< ValueType, RawMode >::getObjectiveValue ( ) const

overridevirtual

Retrieves the value of the objective function.

Note that this may only be called, if the model was found to be optimal, i.e. iff isOptimal() returns true.

Returns: The value of the objective function in the optimal solution.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 416 of file Z3LpSolver.cpp.

◆ isInfeasible()

template<typename ValueType , bool RawMode>

bool storm::solver::Z3LpSolver< ValueType, RawMode >::isInfeasible ( ) const

overridevirtual

Retrieves whether the model was found to be infeasible.

This can only be called after the model has been optimized and not modified afterwards. Otherwise, an exception is thrown.

Returns: True if the model was optimized and found to be infeasible.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 374 of file Z3LpSolver.cpp.

◆ isOptimal()

template<typename ValueType , bool RawMode>

bool storm::solver::Z3LpSolver< ValueType, RawMode >::isOptimal ( ) const

overridevirtual

Retrieves whether the model was found to be optimal, i.e.

neither infeasible nor unbounded. This can only be called after the model has been optimized and not modified afterwards. Otherwise, an exception is thrown.

Returns: True if the model was optimized and found to be neither infeasible nor unbounded.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 386 of file Z3LpSolver.cpp.

◆ isUnbounded()

template<typename ValueType , bool RawMode>

bool storm::solver::Z3LpSolver< ValueType, RawMode >::isUnbounded ( ) const

overridevirtual

Retrieves whether the model was found to be infeasible.

This can only be called after the model has been optimized and not modified afterwards. Otherwise, an exception is thrown.

Returns: True if the model was optimized and found to be unbounded.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 380 of file Z3LpSolver.cpp.

◆ optimize()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::optimize ( ) const

overridevirtual

Optimizes the LP problem previously constructed.

Afterwards, the methods isInfeasible, isUnbounded and isOptimal can be used to query the optimality status.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 368 of file Z3LpSolver.cpp.

◆ pop()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::pop ( )

overridevirtual

Pops a backtracking point from the solver's stack.

This deletes all assertions from the solver's stack that were added after the last call to push().

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 434 of file Z3LpSolver.cpp.

◆ push()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::push ( )

overridevirtual

Pushes a backtracking point on the solver's stack.

A following call to pop() deletes exactly those assertions from the solver's stack that were added after this call.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 428 of file Z3LpSolver.cpp.

◆ setMaximalMILPGap()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::setMaximalMILPGap	(	ValueType const &	gap,
		bool	relative
	)

overridevirtual

Specifies the maximum difference between lower- and upper objective bounds that triggers termination.

That means a solution is considered optimal if upperBound - lowerBound < gap * (relative ? |upperBound| : 1). Only relevant for programs with integer/boolean variables.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 440 of file Z3LpSolver.cpp.

◆ update()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::update ( ) const

overridevirtual

Updates the model to make the variables that have been declared since the last call to update usable.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 350 of file Z3LpSolver.cpp.

◆ writeModelToFile()

template<typename ValueType , bool RawMode>

void storm::solver::Z3LpSolver< ValueType, RawMode >::writeModelToFile ( std::string const & filename ) const

overridevirtual

Writes the current LP problem to the given file.

Parameters

filename The file to which to write the string representation of the LP.

Implements storm::solver::LpSolver< ValueType, RawMode >.

Definition at line 422 of file Z3LpSolver.cpp.

The documentation for this class was generated from the following files:

src/storm/solver/Z3LpSolver.h
src/storm/solver/Z3LpSolver.cpp

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Constant

◆ Constraint

◆ Variable

◆ VariableType

Constructor & Destructor Documentation

◆ Z3LpSolver() [1/4]

◆ Z3LpSolver() [2/4]

◆ Z3LpSolver() [3/4]

◆ Z3LpSolver() [4/4]

◆ ~Z3LpSolver()

Member Function Documentation

◆ addConstraint()

◆ addIndicatorConstraint()

◆ addVariable()

◆ getBinaryValue()

◆ getContinuousValue()

◆ getIntegerValue()

◆ getMILPGap()

◆ getObjectiveValue()

◆ isInfeasible()

◆ isOptimal()

◆ isUnbounded()

◆ optimize()

◆ pop()

◆ push()

◆ setMaximalMILPGap()

◆ update()

◆ writeModelToFile()