operations_research::SymbolsSharedByTwoCardsConstraint Class Reference

Dedicated constraint to count the symbols shared by two cards. More...

Inheritance diagram for operations_research::SymbolsSharedByTwoCardsConstraint:

List of all members.

Public Member Functions
	SymbolsSharedByTwoCardsConstraint (Solver *const solver, const std::vector< IntVar * > &card1_symbol_vars, const std::vector< IntVar * > &card2_symbol_vars, IntVar *const num_symbols_in_common_var)
	This constructor does not take any ownership on its arguments.
virtual	~SymbolsSharedByTwoCardsConstraint ()
virtual void	Post ()
	Adds observers (named Demon) to variable events.
virtual void	InitialPropagate ()
	This is the main propagation method.

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Detailed Description

Dedicated constraint to count the symbols shared by two cards.

This constraint maintains: sum_i(card1_symbol_vars[i]*card2_symbol_vars[i]) == count_var. with all card_symbol_vars[i] being boolean variables.

Definition at line 63 of file dobble_ls.cc.

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Constructor & Destructor Documentation

operations_research::SymbolsSharedByTwoCardsConstraint::SymbolsSharedByTwoCardsConstraint	(	Solver *const	solver,
		const std::vector< IntVar * > &	card1_symbol_vars,
		const std::vector< IntVar * > &	card2_symbol_vars,
		IntVar *const	num_symbols_in_common_var
	)			[inline]

This constructor does not take any ownership on its arguments.

Definition at line 66 of file dobble_ls.cc.

virtual operations_research::SymbolsSharedByTwoCardsConstraint::~SymbolsSharedByTwoCardsConstraint

(

)

[inline, virtual]

Definition at line 87 of file dobble_ls.cc.

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Member Function Documentation

virtual void operations_research::SymbolsSharedByTwoCardsConstraint::Post

(

)

[inline, virtual]

Adds observers (named Demon) to variable events.

These demons are responsible for implementing the propagation algorithm of the constraint.

Definition at line 92 of file dobble_ls.cc.

virtual void operations_research::SymbolsSharedByTwoCardsConstraint::InitialPropagate

(

)

[inline, virtual]

This is the main propagation method.

It scans all card1_symbol_vars * card2_symbol_vars and increments 3 counters:

• min_symbols_in_common if both booleans variables are bound to true.
• max_symbols_in_common if both booleans are not bound to false.

Then we know that num_symbols_in_common_var is in the range [min_symbols_in_common .. max_symbols_in_common].

Now, if num_symbols_in_common_var->Max() == min_symbols_in_common, then all products that contribute to max_symbols_in_common but not to min_symbols_in_common should be set to 0.

Conversely, if num_symbols_in_common_var->Min() == max_symbols_in_common, then all products that contribute to max_symbols_in_common should be set to 1.

Definition at line 128 of file dobble_ls.cc.

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

• or-tools/examples/cpp/dobble_ls.cc