BB_lp Class Reference

Class for operations at the node level. More...

#include <BB_lp.hpp>

Inheritance diagram for BB_lp:

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Collaboration diagram for BB_lp:

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List of all members.

Public Member Functions
virtual OsiSolverInterface *	initialize_solver_interface ()
	Called only once at the beginning, from the root node.
virtual void	initialize_new_search_tree_node (const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts, const BCP_vec< BCP_obj_status > &var_status, const BCP_vec< BCP_obj_status > &cut_status, BCP_vec< int > &var_changed_pos, BCP_vec< double > &var_new_bd, BCP_vec< int > &cut_changed_pos, BCP_vec< double > &cut_new_bd)
	Initialize data members at the start of processing a new subproblem.
virtual void	modify_lp_parameters (OsiSolverInterface *lp, bool in_strong_branching)
	Modify the parameters of the LP solver.
virtual BCP_solution *	test_feasibility (const BCP_lp_result &lp_result, const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts)
	Test feasibility of the LP solution.
virtual void	logical_fixing (const BCP_lp_result &lpres, const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts, const BCP_vec< BCP_obj_status > &var_status, const BCP_vec< BCP_obj_status > &cut_status, const int var_bound_changes_since_logical_fixing, BCP_vec< int > &changed_pos, BCP_vec< double > &new_bd)
	Perform fixing of variables.
virtual void	generate_cuts_in_lp (const BCP_lp_result &lpres, const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts, BCP_vec< BCP_cut * > &new_cuts, BCP_vec< BCP_row * > &new_rows)
	Cut generation.
virtual BCP_solution *	generate_heuristic_solution (const BCP_lp_result &lpres, const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts)
	Simple rounding heuristic.
virtual void	cuts_to_rows (const BCP_vec< BCP_var * > &vars, BCP_vec< BCP_cut * > &cuts, BCP_vec< BCP_row * > &rows, const BCP_lp_result &lpres, BCP_object_origin origin, bool allow_multiple)
	Describes how to get a row of the matrix from the representation of the cut.
virtual BCP_branching_decision	select_branching_candidates (const BCP_lp_result &lpres, const BCP_vec< BCP_var * > &vars, const BCP_vec< BCP_cut * > &cuts, const BCP_lp_var_pool &local_var_pool, const BCP_lp_cut_pool &local_cut_pool, BCP_vec< BCP_lp_branching_object * > &cands)
	Called at the end of each iteration.
virtual void	set_user_data_for_children (BCP_presolved_lp_brobj *best, const int selected)
	Set up the user data for the children according to the chosen branching object.
Constructors and destructors

	BB_lp ()
	Default constructor.
virtual	~BB_lp ()
	Destructor.
Packing and unpacking methods

virtual void	unpack_module_data (BCP_buffer &buf)
	Unpack data sent from the tree manager.
virtual void	pack_cut_algo (const BCP_cut_algo *cut, BCP_buffer &buf)
	Pack algorithmic cuts.
virtual BCP_cut_algo *	unpack_cut_algo (BCP_buffer &buf)
	Unpack algorithmic cuts.
virtual void	pack_user_data (const BCP_user_data *ud, BCP_buffer &buf)
	Pack user data.
virtual MY_user_data *	unpack_user_data (BCP_buffer &buf)
	Unpack user data.
Private Attributes
BB_prob *	p_desc
	Pointer on the description of the problem.
MY_user_data *	p_ud
	Pointer on the description of the user data.
int	in_strong
	in_strong = 1 if and only if in strong branching phase
double	EPS
	Hold the value of EPSILON of class BB_prob.
BCP_vec< BCP_cut * >	algo_cuts
	Hold pointers on generated algorithmic cuts.
std::vector< int >	violated_cuts
	Hold indices of violated indexed cuts.

Detailed Description

Class for operations at the node level.

Definition at line 23 of file BB_lp.hpp.

Constructor & Destructor Documentation

BB_lp::BB_lp ( ) [inline]

Default constructor.

Definition at line 48 of file BB_lp.hpp.

virtual BB_lp::~BB_lp ( ) [inline, virtual]

Destructor.

Definition at line 51 of file BB_lp.hpp.

Member Function Documentation

virtual void BB_lp::unpack_module_data ( BCP_buffer & buf ) [virtual]

Unpack data sent from the tree manager.

Reimplemented from BCP_lp_user.

virtual void BB_lp::pack_cut_algo	(	const BCP_cut_algo *	cut,
		BCP_buffer &	buf
	)			`[virtual]`

Pack algorithmic cuts.

Reimplemented from BCP_lp_user.

virtual BCP_cut_algo* BB_lp::unpack_cut_algo ( BCP_buffer & buf ) [virtual]

Unpack algorithmic cuts.

Reimplemented from BCP_lp_user.

virtual void BB_lp::pack_user_data	(	const BCP_user_data *	ud,
		BCP_buffer &	buf
	)			`[virtual]`

Pack user data.

Reimplemented from BCP_lp_user.

virtual MY_user_data* BB_lp::unpack_user_data ( BCP_buffer & buf ) [virtual]

Unpack user data.

Reimplemented from BCP_lp_user.

virtual OsiSolverInterface* BB_lp::initialize_solver_interface ( ) [virtual]

Called only once at the beginning, from the root node.

Reimplemented from BCP_lp_user.

virtual void BB_lp::initialize_new_search_tree_node	(	const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts,
		const BCP_vec< BCP_obj_status > &	var_status,
		const BCP_vec< BCP_obj_status > &	cut_status,
		BCP_vec< int > &	var_changed_pos,
		BCP_vec< double > &	var_new_bd,
		BCP_vec< int > &	cut_changed_pos,
		BCP_vec< double > &	cut_new_bd
	)			`[virtual]`

Initialize data members at the start of processing a new subproblem.

Reimplemented from BCP_lp_user.

virtual void BB_lp::modify_lp_parameters	(	OsiSolverInterface *	lp,
		bool	in_strong_branching
	)			`[virtual]`

Modify the parameters of the LP solver.

Called at the beginning of the optimization of a node when the node LP is not yet solved.

Reimplemented from BCP_lp_user.

virtual BCP_solution* BB_lp::test_feasibility	(	const BCP_lp_result &	lp_result,
		const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts
	)			`[virtual]`

Test feasibility of the LP solution.

Called after each node LP has been solved. Called even if the node LP was infeasible Called also during strong branching

Reimplemented from BCP_lp_user.

virtual void BB_lp::logical_fixing	(	const BCP_lp_result &	lpres,
		const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts,
		const BCP_vec< BCP_obj_status > &	var_status,
		const BCP_vec< BCP_obj_status > &	cut_status,
		const int	var_bound_changes_since_logical_fixing,
		BCP_vec< int > &	changed_pos,
		BCP_vec< double > &	new_bd
	)			`[virtual]`

Perform fixing of variables.

Called at each iteration, after test_feasibility, if the node is not fathomable

Reimplemented from BCP_lp_user.

virtual void BB_lp::generate_cuts_in_lp	(	const BCP_lp_result &	lpres,
		const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts,
		BCP_vec< BCP_cut * > &	new_cuts,
		BCP_vec< BCP_row * > &	new_rows
	)			`[virtual]`

Cut generation.

Send to BCP the cuts generated in test_feasibility. Use this function to generate standard cuts (Knapsack covers, Lift-and-Project, odd holes, ...).

Reimplemented from BCP_lp_user.

virtual BCP_solution* BB_lp::generate_heuristic_solution	(	const BCP_lp_result &	lpres,
		const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts
	)			`[virtual]`

Simple rounding heuristic.

Reimplemented from BCP_lp_user.

virtual void BB_lp::cuts_to_rows	(	const BCP_vec< BCP_var * > &	vars,
		BCP_vec< BCP_cut * > &	cuts,
		BCP_vec< BCP_row * > &	rows,
		const BCP_lp_result &	lpres,
		BCP_object_origin	origin,
		bool	allow_multiple
	)			`[virtual]`

Describes how to get a row of the matrix from the representation of the cut.

Required method when indexed or algorithmic cuts are used.

Reimplemented from BCP_lp_user.

virtual BCP_branching_decision BB_lp::select_branching_candidates	(	const BCP_lp_result &	lpres,
		const BCP_vec< BCP_var * > &	vars,
		const BCP_vec< BCP_cut * > &	cuts,
		const BCP_lp_var_pool &	local_var_pool,
		const BCP_lp_cut_pool &	local_cut_pool,
		BCP_vec< BCP_lp_branching_object * > &	cands
	)			`[virtual]`

Called at the end of each iteration.

Possible return values are: BCP_DoNotBranch_Fathomed : The node should be fathomed without branching; BCP_DoNotBranch : BCP should continue to work on this node; BCP_DoBranch : Branching must be done. In this case the method returns the branching object candidates in one of the arguments.

Reimplemented from BCP_lp_user.