mirror of
https://github.com/Z3Prover/z3
synced 2025-04-15 05:18:44 +00:00
587 lines
20 KiB
C++
587 lines
20 KiB
C++
/*++
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Copyright (c) 2017 Microsoft Corporation
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Module Name:
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<name>
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Abstract:
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<abstract>
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Author:
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Nikolaj Bjorner (nbjorner)
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Lev Nachmanson (levnach)
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Revision History:
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--*/
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#pragma once
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#include "util/vector.h"
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#include <utility>
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#include "util/debug.h"
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#include "util/buffer.h"
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#include <unordered_map>
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#include <unordered_set>
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#include <string>
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#include "util/lp/lar_constraints.h"
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#include <functional>
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#include "util/lp/lar_core_solver.h"
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#include <algorithm>
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#include "util/lp/numeric_pair.h"
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#include "util/lp/scaler.h"
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#include "util/lp/lp_primal_core_solver.h"
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#include "util/lp/random_updater.h"
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#include <stack>
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#include "util/lp/stacked_value.h"
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#include "util/lp/stacked_vector.h"
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#include "util/lp/implied_bound.h"
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#include "util/lp/bound_analyzer_on_row.h"
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#include "util/lp/conversion_helper.h"
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#include "util/lp/int_solver.h"
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#include "util/lp/nra_solver.h"
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#include "util/lp/bound_propagator.h"
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namespace lp {
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class lar_solver : public column_namer {
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#if Z3DEBUG_CHECK_UNIQUE_TERMS
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struct term_hasher {
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std::size_t operator()(const lar_term *t) const
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{
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using std::size_t;
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using std::hash;
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using std::string;
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size_t seed = 0;
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for (const auto& p : t->m_coeffs) {
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hash_combine(seed, p);
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}
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return seed;
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}
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};
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struct term_ls_comparer {
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bool operator()(const lar_term *a, const lar_term* b) const
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{
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// a is contained in b
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for (auto & p : a->m_coeffs) {
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auto t = b->m_coeffs.find(p.first);
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if (t == b->m_coeffs.end())
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return false;
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if (p.second != t->second)
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return false;
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}
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// zz is contained in b
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for (auto & p : b->m_coeffs) {
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auto t = a->m_coeffs.find(p.first);
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if (t == a->m_coeffs.end())
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return false;
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if (p.second != t->second)
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return false;
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}
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return true;
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}
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};
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std::unordered_set<lar_term*, term_hasher, term_ls_comparer> m_set_of_terms;
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#endif
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//////////////////// fields //////////////////////////
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lp_settings m_settings;
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lp_status m_status;
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stacked_value<simplex_strategy_enum> m_simplex_strategy;
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var_register m_var_register;
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stacked_vector<ul_pair> m_columns_to_ul_pairs;
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vector<lar_base_constraint*> m_constraints;
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private:
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stacked_value<unsigned> m_constraint_count;
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// the set of column indices j such that bounds have changed for j
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int_set m_columns_with_changed_bound;
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int_set m_rows_with_changed_bounds;
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int_set m_basic_columns_with_changed_cost;
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stacked_value<int> m_infeasible_column_index; // such can be found at the initialization step
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stacked_value<unsigned> m_term_count;
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vector<lar_term*> m_terms;
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const var_index m_terms_start_index;
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indexed_vector<mpq> m_column_buffer;
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public:
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lar_core_solver m_mpq_lar_core_solver;
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private:
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int_solver * m_int_solver;
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public :
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unsigned terms_start_index() const { return m_terms_start_index; }
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const vector<lar_term*> & terms() const { return m_terms; }
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const vector<lar_base_constraint*>& constraints() const {
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return m_constraints;
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}
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void set_int_solver(int_solver * int_slv) {
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m_int_solver = int_slv;
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}
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int_solver * get_int_solver() {
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return m_int_solver;
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}
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unsigned constraint_count() const;
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const lar_base_constraint& get_constraint(unsigned ci) const;
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////////////////// methods ////////////////////////////////
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static_matrix<mpq, numeric_pair<mpq>> & A_r();
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static_matrix<mpq, numeric_pair<mpq>> const & A_r() const;
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static_matrix<double, double> & A_d();
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static_matrix<double, double > const & A_d() const;
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static bool valid_index(unsigned j){ return static_cast<int>(j) >= 0;}
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bool column_is_int(unsigned j) const;
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bool column_value_is_int(unsigned j) const {
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return m_mpq_lar_core_solver.m_r_x[j].is_int();
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}
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const impq& get_column_value(unsigned j) const {
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return m_mpq_lar_core_solver.m_r_x[j];
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}
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bool is_term(var_index j) const;
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bool column_is_fixed(unsigned j) const;
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public:
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// init region
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bool strategy_is_undecided() const;
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var_index add_var(unsigned ext_j, bool is_integer);
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void register_new_ext_var_index(unsigned ext_v, bool is_int);
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bool term_is_int(const lar_term * t) const;
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bool var_is_int(var_index v) const;
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void add_non_basic_var_to_core_fields(unsigned ext_j, bool is_int);
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void add_new_var_to_core_fields_for_doubles(bool register_in_basis);
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void add_new_var_to_core_fields_for_mpq(bool register_in_basis);
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// terms
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var_index add_term(const vector<std::pair<mpq, var_index>> & coeffs);
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var_index add_term_undecided(const vector<std::pair<mpq, var_index>> & coeffs);
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bool term_coeffs_are_ok(const vector<std::pair<mpq, var_index>> & coeffs);
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void push_and_register_term(lar_term* t);
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void add_row_for_term(const lar_term * term, unsigned term_ext_index);
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void add_row_from_term_no_constraint(const lar_term * term, unsigned term_ext_index);
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void add_basic_var_to_core_fields();
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constraint_index add_var_bound(var_index j, lconstraint_kind kind, const mpq & right_side) ;
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void update_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index constr_index);
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void add_var_bound_on_constraint_for_term(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index ci);
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void add_constraint_from_term_and_create_new_column_row(unsigned term_j, const lar_term* term,
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lconstraint_kind kind, const mpq & right_side);
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void decide_on_strategy_and_adjust_initial_state();
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void adjust_initial_state();
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void adjust_initial_state_for_lu();
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void adjust_initial_state_for_tableau_rows();
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// this fills the last row of A_d and sets the basis column: -1 in the last column of the row
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void fill_last_row_of_A_d(static_matrix<double, double> & A, const lar_term* ls);
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void update_free_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index constr_ind);
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void update_upper_bound_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index ci);
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void update_boxed_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index ci);
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void update_lower_bound_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index ci);
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void update_fixed_column_type_and_bound(var_index j, lconstraint_kind kind, const mpq & right_side, constraint_index ci);
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//end of init region
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lp_settings & settings();
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lp_settings const & settings() const;
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void clear();
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lar_solver();
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void set_track_pivoted_rows(bool v);
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bool get_track_pivoted_rows() const;
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virtual ~lar_solver();
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unsigned adjust_term_index(unsigned j) const;
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bool use_lu() const;
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bool sizes_are_correct() const;
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bool implied_bound_is_correctly_explained(implied_bound const & be, const vector<std::pair<mpq, unsigned>> & explanation) const;
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void analyze_new_bounds_on_row(
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unsigned row_index,
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bound_propagator & bp);
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void analyze_new_bounds_on_row_tableau(
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unsigned row_index,
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bound_propagator & bp);
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void substitute_basis_var_in_terms_for_row(unsigned i);
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void calculate_implied_bounds_for_row(unsigned i, bound_propagator & bp);
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unsigned adjust_column_index_to_term_index(unsigned j) const;
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var_index local2external(var_index idx) const { return m_var_register.local_to_external(idx); }
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void propagate_bounds_on_a_term(const lar_term& t, bound_propagator & bp, unsigned term_offset);
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void explain_implied_bound(implied_bound & ib, bound_propagator & bp);
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bool term_is_used_as_row(unsigned term) const;
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void propagate_bounds_on_terms(bound_propagator & bp);
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// goes over touched rows and tries to induce bounds
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void propagate_bounds_for_touched_rows(bound_propagator & bp);
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lp_status get_status() const;
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void set_status(lp_status s);
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lp_status find_feasible_solution();
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lp_status solve();
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void fill_explanation_from_infeasible_column(explanation_t & evidence) const;
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unsigned get_total_iterations() const;
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// see http://research.microsoft.com/projects/z3/smt07.pdf
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// This method searches for a feasible solution with as many different values of variables, reverenced in vars, as it can find
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// Attention, after a call to this method the non-basic variables don't necesserarly stick to their bounds anymore
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vector<unsigned> get_list_of_all_var_indices() const;
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void push();
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static void clean_popped_elements(unsigned n, int_set& set);
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static void shrink_inf_set_after_pop(unsigned n, int_set & set);
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void pop(unsigned k);
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class scoped_push {
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lar_solver& m_solver;
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bool m_pop;
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public:
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scoped_push(lar_solver& s):m_solver(s), m_pop(true) { s.push(); }
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~scoped_push() { if (m_pop) m_solver.pop(); }
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void pop() { SASSERT(m_pop); m_solver.pop(); m_pop = false; }
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};
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vector<constraint_index> get_all_constraint_indices() const;
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bool maximize_term_on_tableau(const lar_term & term,
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impq &term_max);
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bool costs_are_zeros_for_r_solver() const;
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bool reduced_costs_are_zeroes_for_r_solver() const;
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void set_costs_to_zero(const lar_term & term);
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void prepare_costs_for_r_solver(const lar_term & term);
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bool maximize_term_on_corrected_r_solver(lar_term & term,
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impq &term_max);
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// starting from a given feasible state look for the maximum of the term
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// return true if found and false if unbounded
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lp_status maximize_term(unsigned ext_j ,
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impq &term_max);
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const lar_term & get_term(unsigned j) const;
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void pop_core_solver_params();
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void pop_core_solver_params(unsigned k);
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void set_upper_bound_witness(var_index j, constraint_index ci);
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void set_lower_bound_witness(var_index j, constraint_index ci);
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void substitute_terms_in_linear_expression( const vector<std::pair<mpq, var_index>>& left_side_with_terms,
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vector<std::pair<mpq, var_index>> &left_side) const;
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void detect_rows_of_bound_change_column_for_nbasic_column(unsigned j);
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void detect_rows_of_bound_change_column_for_nbasic_column_tableau(unsigned j);
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bool use_tableau() const;
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bool use_tableau_costs() const;
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void detect_rows_of_column_with_bound_change(unsigned j);
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void adjust_x_of_column(unsigned j);
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bool row_is_correct(unsigned i) const;
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bool ax_is_correct() const;
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bool tableau_with_costs() const;
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bool costs_are_used() const;
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void change_basic_columns_dependend_on_a_given_nb_column(unsigned j, const numeric_pair<mpq> & delta);
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void update_x_and_inf_costs_for_column_with_changed_bounds(unsigned j);
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void detect_rows_with_changed_bounds_for_column(unsigned j);
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void detect_rows_with_changed_bounds();
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void update_x_and_inf_costs_for_columns_with_changed_bounds();
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void update_x_and_inf_costs_for_columns_with_changed_bounds_tableau();
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void solve_with_core_solver();
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numeric_pair<mpq> get_basic_var_value_from_row_directly(unsigned i);
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numeric_pair<mpq> get_basic_var_value_from_row(unsigned i);
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template <typename K, typename L>
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void add_last_rows_to_lu(lp_primal_core_solver<K,L> & s);
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bool x_is_correct() const;
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bool var_is_registered(var_index vj) const;
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unsigned constraint_stack_size() const;
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void fill_last_row_of_A_r(static_matrix<mpq, numeric_pair<mpq>> & A, const lar_term * ls);
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template <typename U, typename V>
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void create_matrix_A(static_matrix<U, V> & matr);
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template <typename U, typename V>
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void copy_from_mpq_matrix(static_matrix<U, V> & matr);
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bool try_to_set_fixed(column_info<mpq> & ci);
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column_type get_column_type(unsigned j) const;
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std::string get_column_name(unsigned j) const;
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bool all_constrained_variables_are_registered(const vector<std::pair<mpq, var_index>>& left_side);
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constraint_index add_constraint(const vector<std::pair<mpq, var_index>>& left_side_with_terms, lconstraint_kind kind_par, const mpq& right_side_parm);
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bool all_constraints_hold() const;
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bool constraint_holds(const lar_base_constraint & constr, std::unordered_map<var_index, mpq> & var_map) const;
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bool the_relations_are_of_same_type(const vector<std::pair<mpq, unsigned>> & evidence, lconstraint_kind & the_kind_of_sum) const;
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static void register_in_map(std::unordered_map<var_index, mpq> & coeffs, const lar_base_constraint & cn, const mpq & a);
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static void register_monoid_in_map(std::unordered_map<var_index, mpq> & coeffs, const mpq & a, unsigned j);
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bool the_left_sides_sum_to_zero(const vector<std::pair<mpq, unsigned>> & evidence) const;
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bool the_right_sides_do_not_sum_to_zero(const vector<std::pair<mpq, unsigned>> & evidence);
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bool explanation_is_correct(const vector<std::pair<mpq, unsigned>>& explanation) const;
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bool inf_explanation_is_correct() const;
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mpq sum_of_right_sides_of_explanation(const vector<std::pair<mpq, unsigned>> & explanation) const;
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bool has_lower_bound(var_index var, constraint_index& ci, mpq& value, bool& is_strict) const;
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bool has_upper_bound(var_index var, constraint_index& ci, mpq& value, bool& is_strict) const;
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bool has_value(var_index var, mpq& value) const;
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void get_infeasibility_explanation(vector<std::pair<mpq, constraint_index>> & explanation) const;
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void get_infeasibility_explanation_for_inf_sign(
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vector<std::pair<mpq, constraint_index>> & explanation,
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const vector<std::pair<mpq, unsigned>> & inf_row,
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int inf_sign) const;
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void get_model(std::unordered_map<var_index, mpq> & variable_values) const;
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void get_model_do_not_care_about_diff_vars(std::unordered_map<var_index, mpq> & variable_values) const;
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std::string get_variable_name(var_index vi) const;
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// print utilities
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std::ostream& print_constraint(constraint_index ci, std::ostream & out) const;
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std::ostream& print_constraints(std::ostream& out) const ;
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std::ostream& print_terms(std::ostream& out) const;
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std::ostream& print_left_side_of_constraint(const lar_base_constraint * c, std::ostream & out) const;
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std::ostream& print_term(lar_term const& term, std::ostream & out) const;
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std::ostream& print_term_as_indices(lar_term const& term, std::ostream & out) const;
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std::ostream& print_constraint(const lar_base_constraint * c, std::ostream & out) const;
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std::ostream& print_implied_bound(const implied_bound& be, std::ostream & out) const;
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mpq get_left_side_val(const lar_base_constraint & cns, const std::unordered_map<var_index, mpq> & var_map) const;
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void fill_var_set_for_random_update(unsigned sz, var_index const * vars, vector<unsigned>& column_list);
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void random_update(unsigned sz, var_index const * vars);
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void pivot_fixed_vars_from_basis();
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void pop();
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bool column_represents_row_in_tableau(unsigned j);
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void make_sure_that_the_bottom_right_elem_not_zero_in_tableau(unsigned i, unsigned j);
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void remove_last_row_and_column_from_tableau(unsigned j);
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void remove_last_column_from_A();
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void remove_last_column_from_basis_tableau(unsigned j);
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void remove_last_column_from_tableau();
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void pop_tableau();
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void clean_inf_set_of_r_solver_after_pop();
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void shrink_explanation_to_minimum(vector<std::pair<mpq, constraint_index>> & explanation) const;
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bool column_value_is_integer(unsigned j) const {
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return get_column_value(j).is_int();
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}
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bool column_is_real(unsigned j) const {
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return !column_is_int(j);
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}
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bool model_is_int_feasible() const;
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const impq & column_lower_bound(unsigned j) const {
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return m_mpq_lar_core_solver.lower_bound(j);
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}
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const impq & column_upper_bound(unsigned j) const {
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return m_mpq_lar_core_solver.upper_bound(j);
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}
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bool column_is_bounded(unsigned j) const {
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return m_mpq_lar_core_solver.column_is_bounded(j);
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}
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void get_bound_constraint_witnesses_for_column(unsigned j, constraint_index & lc, constraint_index & uc) const {
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const ul_pair & ul = m_columns_to_ul_pairs[j];
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lc = ul.lower_bound_witness();
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uc = ul.upper_bound_witness();
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}
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indexed_vector<mpq> & get_column_in_lu_mode(unsigned j) {
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m_column_buffer.clear();
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m_column_buffer.resize(A_r().row_count());
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m_mpq_lar_core_solver.m_r_solver.solve_Bd(j, m_column_buffer);
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return m_column_buffer;
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}
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bool bound_is_integer_for_integer_column(unsigned j, const mpq & right_side) const;
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const row_strip<mpq> & get_row(unsigned i) {
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return A_r().m_rows[i];
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}
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unsigned get_base_column_in_row(unsigned row_index) const {
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return m_mpq_lar_core_solver.m_r_solver.get_base_column_in_row(row_index);
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}
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constraint_index get_column_upper_bound_witness(unsigned j) const {
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return m_columns_to_ul_pairs()[j].upper_bound_witness();
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}
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constraint_index get_column_lower_bound_witness(unsigned j) const {
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return m_columns_to_ul_pairs()[j].lower_bound_witness();
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}
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void subs_term_columns(lar_term& t) {
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vector<std::pair<unsigned,unsigned>> columns_to_subs;
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for (const auto & m : t.m_coeffs) {
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unsigned tj = adjust_column_index_to_term_index(m.first);
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if (tj == m.first) continue;
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columns_to_subs.push_back(std::make_pair(m.first, tj));
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}
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for (const auto & p : columns_to_subs) {
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auto it = t.m_coeffs.find(p.first);
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lp_assert(it != t.m_coeffs.end());
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const lar_term& lt = get_term(p.second);
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mpq v = it->second;
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t.m_coeffs.erase(it);
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t.m_coeffs[p.second] = v;
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}
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}
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bool has_int_var() const;
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bool has_inf_int() const {
|
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for (unsigned j = 0; j < column_count(); j++) {
|
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if (column_is_int(j) && ! column_value_is_int(j))
|
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return true;
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}
|
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return false;
|
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}
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bool r_basis_has_inf_int() const {
|
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for (unsigned j : r_basis()) {
|
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if (column_is_int(j) && ! column_value_is_int(j))
|
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return true;
|
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}
|
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return false;
|
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}
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|
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lar_core_solver & get_core_solver() { return m_mpq_lar_core_solver; }
|
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bool column_corresponds_to_term(unsigned) const;
|
|
void catch_up_in_updating_int_solver();
|
|
var_index to_column(unsigned ext_j) const;
|
|
bool tighten_term_bounds_by_delta(unsigned, const impq&);
|
|
void round_to_integer_solution();
|
|
void update_delta_for_terms(const impq & delta, unsigned j, const vector<unsigned>&);
|
|
void fill_vars_to_terms(vector<vector<unsigned>> & vars_to_terms);
|
|
unsigned column_count() const { return A_r().column_count(); }
|
|
const vector<unsigned> & r_basis() const { return m_mpq_lar_core_solver.r_basis(); }
|
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const vector<unsigned> & r_nbasis() const { return m_mpq_lar_core_solver.r_nbasis(); }
|
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bool get_equality_and_right_side_for_term_on_current_x(unsigned i, mpq &rs, constraint_index& ci, bool &upper_bound) const;
|
|
bool remove_from_basis(unsigned);
|
|
lar_term get_term_to_maximize(unsigned ext_j) const;
|
|
void set_cut_strategy(unsigned cut_frequency);
|
|
bool sum_first_coords(const lar_term& t, mpq & val) const;
|
|
};
|
|
}
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