operations_research::DobbleFilter Class Reference

Local Search Filter. More...

Inheritance diagram for operations_research::DobbleFilter:

List of all members.

Public Member Functions
	DobbleFilter (const IntVar *const *card_symbol_vars, int num_vars, int num_cards, int num_symbols, int num_symbols_per_card)
virtual void	OnSynchronize ()
	We build the current bitmap and the matrix of violation cost between any two cards.
virtual bool	Accept (const Assignment *delta, const Assignment *unused_deltadelta)
	The LocalSearchFilter::Accept() API also takes a deltadelta, which is the difference between the current delta and the last delta that was given to Accept() -- but we don't use it here.
Classes
struct	UndoChange
	Undo information after an evaluation.

---

Detailed Description

Local Search Filter.

A filter is responsible for rejecting a local search move faster than what the propagation of the constraint solver would do. Its API consists in:

• The constructor, which takes as input a reference to all the variables relevant to the filter.
• OnSynchronize(), called at the beginning of the search and after each move to a new solution (when the local search restarts from it).
• Accept(), which takes as input an attempted move (in the form of a Delta to tentatively apply to the variables), and returns true iff this move is found valid.

To decide if a move is valid, first this DobbleFilter builds a bitmap of symbols per card. Then for each move, it updates the bitmap according to the move and checks the following constraints:

• First, each card still has num_symbols_per_card symbols. - The cost of the assignment described by the move is better than the current one. After the check is done, the original bitmap is restored if the move was rejected, so as to be ready for the next evaluation.

Please note that this filter uses a fixed size bitset and effectively limits the number of cards to 63, and thus the number of symbols per card to 8.

Definition at line 455 of file dobble_ls.cc.

---

Constructor & Destructor Documentation

operations_research::DobbleFilter::DobbleFilter	(	const IntVar *const *	card_symbol_vars,
		int	num_vars,
		int	num_cards,
		int	num_symbols,
		int	num_symbols_per_card
	)			[inline]

Definition at line 457 of file dobble_ls.cc.

---

Member Function Documentation

virtual void operations_research::DobbleFilter::OnSynchronize

(

)

[inline, virtual]

We build the current bitmap and the matrix of violation cost between any two cards.

Definition at line 472 of file dobble_ls.cc.

virtual bool operations_research::DobbleFilter::Accept	(	const Assignment *	delta,
		const Assignment *	unused_deltadelta
	)			[inline, virtual]

The LocalSearchFilter::Accept() API also takes a deltadelta, which is the difference between the current delta and the last delta that was given to Accept() -- but we don't use it here.

Definition at line 494 of file dobble_ls.cc.

---

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

• or-tools/examples/cpp/dobble_ls.cc