operations_research::sat::Model Class Reference

Detailed Description

Class that owns everything related to a particular optimization model.

This class is actually a fully generic wrapper that can hold any type of constraints, watchers, solvers and provide a mechanism to wire them together.

Definition at line 40 of file model.h.

#include <model.h>

Public Member Functions
	Model ()=default
	~Model ()
	Model (std::string name)
	Model (const Model &)=delete
	This type is neither copyable nor movable.
Model &	operator= (const Model &)=delete
template<typename T>
T	Add (std::function< T(Model *)> f)
template<typename T>
T	Get (std::function< T(const Model &)> f) const
	Similar to Add() but this is const.
template<typename T>
T *	GetOrCreate ()
template<typename T>
const T *	Get () const
template<typename T>
T *	Mutable () const
template<typename T>
T *	TakeOwnership (T *t)
template<typename T>
T *	Create ()
template<typename T>
void	Register (T *non_owned_class)
const std::string &	Name () const

Constructor & Destructor Documentation

Model() [1/3]

operations_research::sat::Model::Model ( )

default

~Model()

operations_research::sat::Model::~Model ( )

inline

The order of deletion seems to be platform dependent. We force a reverse order on the cleanup vector.

Definition at line 44 of file model.h.

Model() [2/3]

operations_research::sat::Model::Model ( std::string name )

inlineexplicit

When there is more than one model in an application, it makes sense to name them for debugging or logging.

Definition at line 56 of file model.h.

Model() [3/3]

operations_research::sat::Model::Model ( const Model & )

delete

This type is neither copyable nor movable.

Member Function Documentation

Add()

template<typename T>

T operations_research::sat::Model::Add ( std::function< T(Model *)> f )

inline

This makes it possible to have a nicer API on the client side, and it allows both of these forms:

• ConstraintCreationFunction(constraint_args, &model);
• model.Add(ConstraintCreationFunction(constraint_args));

The second form is a bit nicer for the client and it also allows to store constraints and add them later. However, the function creating the constraint is slighly more involved.

std::function<void(Model*)> ConstraintCreationFunction(constraint_args) {
  return [=] (Model* model) {
     ... the same code ...
  };
}

We also have a templated return value for the functions that need it like

const BooleanVariable b = model.Add(NewBooleanVariable());
const IntegerVariable i = model.Add(NewWeightedSum(weights, variables));

Definition at line 87 of file model.h.

Create()

template<typename T>

T * operations_research::sat::Model::Create ( )

inline

This returns a non-singleton object owned by the model and created with the T(Model* model) constructor if it exist or the T() constructor otherwise. It is just a shortcut to new + TakeOwnership().

Definition at line 165 of file model.h.

Get() [1/2]

template<typename T>

const T * operations_research::sat::Model::Get ( ) const

inline

Likes GetOrCreate() but do not create the object if it is non-existing.

This returns a const version of the object.

Definition at line 133 of file model.h.

Get() [2/2]

template<typename T>

T operations_research::sat::Model::Get ( std::function< T(const Model &)> f ) const

inline

Similar to Add() but this is const.

Definition at line 93 of file model.h.

GetOrCreate()

template<typename T>

T * operations_research::sat::Model::GetOrCreate ( )

inline

Returns an object of type T that is unique to this model (like a "local" singleton). This returns an already created instance or create a new one if needed using the T(Model* model) constructor if it exist or T() otherwise.

This works a bit like in a dependency injection framework and allows to really easily wire all the classes that make up a solver together. For instance a constraint can depends on the LiteralTrail, or the IntegerTrail or both, it can depend on a Watcher class to register itself in order to be called when needed and so on.

IMPORTANT: the Model* constructor functions shouldn't form a cycle between each other, otherwise this will crash the program.

New element.

Todo

(user): directly store std::unique_ptr<> in singletons_?

Definition at line 112 of file model.h.

Mutable()

template<typename T>

T * operations_research::sat::Model::Mutable ( ) const

inline

Same as Get(), but returns a mutable version of the object.

Definition at line 143 of file model.h.

Name()

const std::string & operations_research::sat::Model::Name ( ) const

inline

Definition at line 183 of file model.h.

operator=()

Model & operations_research::sat::Model::operator= ( const Model & )

delete

Register()

template<typename T>

void operations_research::sat::Model::Register ( T * non_owned_class )

inline

Register a non-owned class that will be "singleton" in the model.

It is an error to call this on an already registered class.

Definition at line 177 of file model.h.

TakeOwnership()

template<typename T>

T * operations_research::sat::Model::TakeOwnership ( T * t )

inline

Gives ownership of a pointer to this model.

It will be destroyed when the model is.

Definition at line 154 of file model.h.

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

• ortools/sat/model.h