A SCIP optimization model. More...

#include <model.hpp>

Public Member Functions
	Model (const std::string &name, SCIP *scip=nullptr, bool includeDefaultPlugins=true)
	Creates an empty problem and sets the optimization goal to Sense::MINIMIZE.

	~Model ()
	Releases the variables and constraints.

void	addConstr (const LinIneq &ineq, const std::string &name)
	Adds a constraint to the model.

bool	addSolution (const InitialSolution &initialSolution, bool printReason=true, bool completely=true, bool checkBounds=true, bool checkIntegrality=true, bool checkLpRows=true)
	Adds a solution to SCIP's solution pool.

Var &	addVar (const std::string &name, SCIP_Real coeff=0.0, VarType varType=VarType::CONTINUOUS, std::optional< SCIP_Real > lb=0.0, std::optional< SCIP_Real > ub=1.0)
	Adds a variable to the model.

template<size_t NumVars, typename CoeffType = ConstantCoefficient>
std::array< Var, NumVars >	addVars (const std::string &prefix, const CoeffType &coeffs=COEFF_ZERO, VarType varType=VarType::CONTINUOUS, std::optional< SCIP_Real > lb=0.0, std::optional< SCIP_Real > ub=1.0)
	Adds multiple variables to the model.

template<typename CoeffType = ConstantCoefficient>
std::vector< Var >	addVars (const std::string &prefix, size_t numVars, const CoeffType &coeffs=COEFF_ZERO, VarType varType=VarType::CONTINUOUS, std::optional< SCIP_Real > lb=0.0, std::optional< SCIP_Real > ub=1.0)
	Adds multiple variables to the model.

SCIP_Real	epsilon () const
	Value treated as zero.

Solution	getBestSol () const
	Returns the best feasible primal solution found so far or best solution candidate.

SCIP_Retcode	getLastReturnCode () const
	Gets the return code of the last call to SCIP's C API when the default call wrapper is used.

int	getNSols () const
	Returns the number of feasible primal solutions stored in the solution storage.

double	getPrimalbound () const
	Returns the objective value of best solution.

template<typename T >
T	getSolvingStatistic (const statistics::Statistic< T > &statistic) const
	Query statistics about the solving process.

SCIP_Status	getStatus () const
	Returns the solution status.

SCIP_Real	infinity () const
	Infinity according the SCIP config.

bool	isZero (SCIP_Real value) const
	Checks, if value is in range epsilon of 0.0.

SCIP_Real	round (SCIP_Real value) const
	Rounds value to the nearest integer with epsilon tolerance.

Scip *	scip () const
	Returns a pointer to the underlying SCIP object.

void	setObjsense (Sense objsense)
	Set objective goal.

template<typename T , typename PT >
void	setParam (params::Param< PT > parameter, T value)
	Sets a parameter.

void	setScipCallWrapper (std::function< void(SCIP_Retcode)> wrapper)
	Replace the current wrapper for every call to SCIP's C API.

void	solve ()
	Solve the model.

void	writeOrigProblem (const std::filesystem::directory_entry &filename, bool genericNames=false) const
	Writes original problem to file.

void	writeOrigProblem (const std::string &extension, bool genericNames=false) const
	Writes original problem to standard output.

Detailed Description

A SCIP optimization model.

Variables and constraints are automatically released when the model is destructed.

Since: 1.0.0

Definition at line 40 of file model.hpp.

Constructor & Destructor Documentation

◆ Model()

scippp::Model::Model	(	const std::string &	name,
		SCIP *	scip = nullptr,
		bool	includeDefaultPlugins = true )

explicit

Creates an empty problem and sets the optimization goal to Sense::MINIMIZE.

By default, all calls to the underlying C API are wrapped and the last return code is stored.

Since: 1.0.0

Parameters

name	for the problem.
scip	to create the problem in. If `nullptr`, a new SCIP data structure will be created.
includeDefaultPlugins	if `true`, the default plugins are added to `scip`.

◆ ~Model()

scippp::Model::~Model ( )

Releases the variables and constraints.

Since: 1.0.0

Member Function Documentation

◆ addConstr()

void scippp::Model::addConstr	(	const LinIneq &	ineq,
		const std::string &	name )

Adds a constraint to the model.

Since: 1.0.0

Parameters

ineq	linear inequality to add.
name	for the constraint when the model is written.

◆ addSolution()

bool scippp::Model::addSolution	(	const InitialSolution &	initialSolution,
		bool	printReason = true,
		bool	completely = true,
		bool	checkBounds = true,
		bool	checkIntegrality = true,
		bool	checkLpRows = true )

Adds a solution to SCIP's solution pool.

Since: 1.3.0

Parameters

initialSolution	to add to the solution pool.
printReason	Should all reasons of violations be printed?
completely	Should all violations be checked if `printReason` is true?
checkBounds	Should the bounds of the variables be checked?
checkIntegrality	Should integrality be checked?
checkLpRows	Do constraints represented by rows in the current LP have to be checked?

Returns: true iff the solution was feasible and stored in the solution storage (i.e, good enough to keep).

◆ addVar()

Var & scippp::Model::addVar	(	const std::string &	name,
		SCIP_Real	coeff = 0.0,
		VarType	varType = VarType::CONTINUOUS,
		std::optional< SCIP_Real >	lb = 0.0,
		std::optional< SCIP_Real >	ub = 1.0 )

Adds a variable to the model.

Since: 1.0.0

Parameters

name	of the variable when the model is written.
coeff	Coefficient in the objective function.
varType	variable type.
lb	lower bound. `std::nullopt` is interpreted as -infinity.
ub	upper bound. `std::nullopt` is interpreted as infinity.

Returns: Reference to the newly created variable.

◆ addVars() [1/2]

template<size_t NumVars, typename CoeffType = ConstantCoefficient>

std::array< Var, NumVars > scippp::Model::addVars	(	const std::string &	prefix,
		const CoeffType &	coeffs = COEFF_ZERO,
		VarType	varType = VarType::CONTINUOUS,
		std::optional< SCIP_Real >	lb = 0.0,
		std::optional< SCIP_Real >	ub = 1.0 )

inline

Adds multiple variables to the model.

This method can be used when the number of variables to add is known at compile time. The result can be used in a structured binding.

Since: 1.0.0

Template Parameters

NumVars	Number of variables to add.
CoeffType	Type of the object holding the coefficients. They are accessed via [i] where i goes from 0 to `NumVars` - 1.

Parameters

prefix	to construct variable names from: prefix + index.
coeffs	Object holding the coefficients for the objective function.
varType	variable type.
lb	lower bound.
ub	upper bound.

Returns: Array of variables.

Definition at line 152 of file model.hpp.

References addVars().

◆ addVars() [2/2]

template<typename CoeffType = ConstantCoefficient>

std::vector< Var > scippp::Model::addVars	(	const std::string &	prefix,
		size_t	numVars,
		const CoeffType &	coeffs = COEFF_ZERO,
		VarType	varType = VarType::CONTINUOUS,
		std::optional< SCIP_Real >	lb = 0.0,
		std::optional< SCIP_Real >	ub = 1.0 )

inline

Adds multiple variables to the model.

Since: 1.0.0

Template Parameters

CoeffType Type of the object holding the coefficients. They are accessed via [i] where i goes from 0 to numVars - 1.

Parameters

prefix	to construct variable names from: prefix + index.
numVars	number of variables to create.
coeffs	Object holding the coefficients for the objective function.
varType	variable type.
lb	lower bound. `std::nullopt` is interpreted as -infinity.
ub	upper bound. `std::nullopt` is interpreted as infinity.

Returns: Vector of variables.

Definition at line 118 of file model.hpp.

References addVar().

◆ epsilon()

SCIP_Real scippp::Model::epsilon ( ) const

nodiscard

Value treated as zero.

Since: 1.1.0

Returns: value treated as zero.

◆ getBestSol()

Solution scippp::Model::getBestSol ( ) const

nodiscard

Returns the best feasible primal solution found so far or best solution candidate.

Since: 1.0.0

Returns: best feasible primal solution.

◆ getLastReturnCode()

SCIP_Retcode scippp::Model::getLastReturnCode ( ) const

nodiscard

Gets the return code of the last call to SCIP's C API when the default call wrapper is used.

Since: 1.0.0

Returns: return code of the last call to SCIP's C API.

◆ getNSols()

int scippp::Model::getNSols ( ) const

nodiscard

Returns the number of feasible primal solutions stored in the solution storage.

Since: 1.0.0

Returns: number of solutions.

◆ getPrimalbound()

double scippp::Model::getPrimalbound ( ) const

nodiscard

Returns the objective value of best solution.

Since: 1.0.0

Deprecated: since 1.2.0, use getSolvingStatistic with statistics::PRIMALBOUND instead.

Returns: objective value of best solution.

◆ getSolvingStatistic()

template<typename T >

T scippp::Model::getSolvingStatistic ( const statistics::Statistic< T > & statistic ) const

inlinenodiscard

Query statistics about the solving process.

Template Parameters

T	Type of the statistics value.

Since: 1.2.0

Parameters

statistic Statistics value to access.

Returns: Statistics value.

Definition at line 232 of file model.hpp.

◆ getStatus()

SCIP_Status scippp::Model::getStatus ( ) const

nodiscard

Returns the solution status.

Since: 1.0.0

Returns: solution status.

◆ infinity()

SCIP_Real scippp::Model::infinity ( ) const

nodiscard

Infinity according the SCIP config.

To be used in variable bounds and constants in constraints.

Since: 1.0.0

Returns: infinity according the SCIP config.

◆ isZero()

bool scippp::Model::isZero ( SCIP_Real value ) const

nodiscard

Checks, if value is in range epsilon of 0.0.

Since: 1.1.0

Parameters

value to check

Returns: true iff the value is in range epsilon of 0.0.

◆ round()

SCIP_Real scippp::Model::round ( SCIP_Real value ) const

nodiscard

Rounds value to the nearest integer with epsilon tolerance.

Since: 1.1.0

Parameters

value to round

Returns: nearest integer as double

◆ scip()

Scip * scippp::Model::scip ( ) const

nodiscard

Returns a pointer to the underlying SCIP object.

Since: 1.0.0

Attention: Use this to access the raw SCIP object. That is required only for use-cases not supported by SCIP++. Consider adding the feature you are using to SCIP++!

Returns: the underlying SCIP object.

◆ setObjsense()

void scippp::Model::setObjsense ( Sense objsense )

Set objective goal.

Since: 1.0.0

Parameters

objsense Minimize or Maximize.

◆ setParam()

template<typename T , typename PT >

void scippp::Model::setParam	(	params::Param< PT >	parameter,
		T	value )

inline

Sets a parameter.

See the namespace scippp::params for a list of parameters, or create new ones using params::Param.

Since: 1.0.0

Template Parameters

T	Type of the value.
PT	Value type the parameter expects

Parameters

parameter	to set.
value	to set the parameter to.

Definition at line 273 of file model.hpp.

References scippp::params::Param< baseType >::scipName.

◆ setScipCallWrapper()

void scippp::Model::setScipCallWrapper ( std::function< void(SCIP_Retcode)> wrapper )

Replace the current wrapper for every call to SCIP's C API.

Since: 1.0.0

Parameters

wrapper New wrapper tp use.

◆ solve()

void scippp::Model::solve ( )

Solve the model.

Since: 1.0.0

◆ writeOrigProblem() [1/2]

void scippp::Model::writeOrigProblem	(	const std::filesystem::directory_entry &	filename,
		bool	genericNames = false ) const

Writes original problem to file.

Since: 1.1.0

Parameters

filename	output file name including extension
genericNames	using generic variable (x0, x1, ...) and constraint names (c0, c1, ...) instead of the user-given names?

Attention: Do not use an std::string or std::filesystem::path as argument filename, as this will call the other overload instead!

◆ writeOrigProblem() [2/2]

void scippp::Model::writeOrigProblem	(	const std::string &	extension,
		bool	genericNames = false ) const

Writes original problem to standard output.

Since: 1.1.0

Parameters

extension	file extension to derive the output format from
genericNames	using generic variable (x0, x1, ...) and constraint names (c0, c1, ...) instead of the user-given names?

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

model.hpp

SCIP++ refs/heads/main

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Model()

◆ ~Model()

Member Function Documentation

◆ addConstr()

◆ addSolution()

◆ addVar()

◆ addVars() [1/2]

◆ addVars() [2/2]

◆ epsilon()

◆ getBestSol()

◆ getLastReturnCode()

◆ getNSols()

◆ getPrimalbound()

◆ getSolvingStatistic()

◆ getStatus()

◆ infinity()

◆ isZero()

◆ round()

◆ scip()

◆ setObjsense()

◆ setParam()

◆ setScipCallWrapper()

◆ solve()

◆ writeOrigProblem() [1/2]

◆ writeOrigProblem() [2/2]