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z3/src/util/lp/lp_dual_simplex.h
2018-02-10 09:56:33 +07:00

96 lines
2.4 KiB
C++

/*++
Copyright (c) 2017 Microsoft Corporation
Module Name:
<name>
Abstract:
<abstract>
Author:
Lev Nachmanson (levnach)
Revision History:
--*/
#pragma once
#include "util/vector.h"
#include "util/lp/lp_utils.h"
#include "util/lp/lp_solver.h"
#include "util/lp/lp_dual_core_solver.h"
namespace lp {
template <typename T, typename X>
class lp_dual_simplex: public lp_solver<T, X> {
lp_dual_core_solver<T, X> * m_core_solver;
vector<T> m_b_copy;
vector<T> m_low_bounds; // We don't have a convention here that all low bounds are zeros. At least it does not hold for the first stage solver
vector<column_type> m_column_types_of_core_solver;
vector<column_type> m_column_types_of_logicals;
vector<bool> m_can_enter_basis;
public:
~lp_dual_simplex() override {
if (m_core_solver != nullptr) {
delete m_core_solver;
}
}
lp_dual_simplex() : m_core_solver(nullptr) {}
void decide_on_status_after_stage1();
void fix_logical_for_stage2(unsigned j);
void fix_structural_for_stage2(unsigned j);
void unmark_boxed_and_fixed_columns_and_fix_structural_costs();
void restore_right_sides();
void solve_for_stage2();
void fill_x_with_zeros();
void stage1();
void stage2();
void fill_first_stage_solver_fields();
column_type get_column_type(unsigned j);
void fill_costs_bounds_types_and_can_enter_basis_for_the_first_stage_solver_structural_column(unsigned j);
void fill_costs_bounds_types_and_can_enter_basis_for_the_first_stage_solver_logical_column(unsigned j);
void fill_costs_and_bounds_and_column_types_for_the_first_stage_solver();
void set_type_for_logical(unsigned j, column_type col_type) {
this->m_column_types_of_logicals[j - this->number_of_core_structurals()] = col_type;
}
void fill_first_stage_solver_fields_for_row_slack_and_artificial(unsigned row,
unsigned & slack_var,
unsigned & artificial);
void augment_matrix_A_and_fill_x_and_allocate_some_fields();
void copy_m_b_aside_and_set_it_to_zeros();
void find_maximal_solution() override;
T get_column_value(unsigned column) const override {
return this->get_column_value_with_core_solver(column, m_core_solver);
}
T get_current_cost() const override;
};
}