mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-07-23 04:38:53 +00:00
Code Activity

no calling cut_solver when there are bounded columns

Browse source 
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

use special bounds inf find_cube for x+y, x-y

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

bug fixes in column patching, add stats to patching, restructure int_solver

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

comment out m_old_values from int_solver

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

avoid calling pivot_fixed_vars_from_basis() in int_solver

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

fix the return value from path_nbasic_columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

fix the return value from path_nbasic_columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

work in patch_columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

work on int_solver check()

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

exit from find_free_interval() when l >= u

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

experiment with branching on nbasic columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

remove m_old_values

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

add rounding to patch_columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

qflia

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

patch all columns, round non-patched, branch or basic columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

refactor int_solver::check()

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

restore  move_non_basic_columns_to_bounds() after a failure in find_cube()

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

optimize gomory cuts search

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

produce gomory cuts without moving columns to bounds

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

call find_feasible_solution() after moving columns

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

alway move colums to bounds before gomory cut

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

merge from best branch

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2018-04-03 17:29:58 -07:00
parent 7e82ab595e
commit c04bcb411d
13 changed files with 341 additions and 276 deletions
Download patch file Download diff file Expand all files Collapse all files

76
src/util/lp/int_solver.h
View file

@ -30,14 +30,14 @@ class lar_solver;
template <typename T, typename X>
struct lp_constraint;
enum class lia_move {
ok,
branch,
cut,
conflict,
continue_with_check,
give_up,
unsat
};
sat,
branch,
cut,
conflict,
continue_with_check,
undef,
unsat
};
struct explanation {
vector<std::pair<mpq, constraint_index>> m_explanation;
@ -52,11 +52,13 @@ struct explanation {
class int_solver {
public:
// fields
lar_solver *m_lar_solver;
int_set m_old_values_set;
vector<impq> m_old_values_data;
unsigned m_branch_cut_counter;
cut_solver m_cut_solver;
lar_solver * m_lar_solver;
unsigned m_branch_cut_counter;
cut_solver m_cut_solver;
lar_term* m_t; // the term to return in the cut
mpq *m_k; // the right side of the cut
explanation *m_ex; // the conflict explanation
bool *m_upper; // we have a cut m_t*x <= k if m_upper is true nad m_t*x >= k otherwise
// methods
int_solver(lar_solver* lp);
@ -69,7 +71,7 @@ private:
// how to tighten bounds for integer variables.
bool gcd_test_for_row(static_matrix<mpq, numeric_pair<mpq>> & A, unsigned i, explanation &);
bool gcd_test_for_row(static_matrix<mpq, numeric_pair<mpq>> & A, unsigned i);
// gcd test
// 5*x + 3*y + 6*z = 5
@ -79,25 +81,17 @@ private:
// this is unsolvable because 5/3 is not an integer.
// so we create a lemma that rules out this condition.
//
bool gcd_test(explanation & ); // returns false in case of failure. Creates a theory lemma in case of failure.
// create goromy cuts
// either creates a conflict or a bound.
// branch and bound:
// decide what to branch and bound on
// creates a fresh inequality.
bool gcd_test(); // returns false in case of failure. Creates a theory lemma in case of failure.
bool branch(const lp_constraint<mpq, mpq> & new_inequality);
bool ext_gcd_test(const row_strip<mpq>& row,
mpq const & least_coeff,
mpq const & lcm_den,
mpq const & consts,
explanation & ex);
void fill_explanation_from_fixed_columns(const row_strip<mpq> & row, explanation &);
void add_to_explanation_from_fixed_or_boxed_column(unsigned j, explanation &);
void patch_int_infeasible_non_basic_column(unsigned j);
void patch_int_infeasible_nbasic_columns();
mpq const & consts);
void fill_explanation_from_fixed_columns(const row_strip<mpq> & row);
void add_to_explanation_from_fixed_or_boxed_column(unsigned j);
void patch_nbasic_column(unsigned j);
lia_move patch_nbasic_columns();
bool get_freedom_interval_for_column(unsigned j, bool & inf_l, impq & l, bool & inf_u, impq & u, mpq & m);
const impq & lower_bound(unsigned j) const;
const impq & upper_bound(unsigned j) const;
@ -111,7 +105,6 @@ private:
void set_value_for_nbasic_column(unsigned j, const impq & new_val);
void set_value_for_nbasic_column_ignore_old_values(unsigned j, const impq & new_val);
bool non_basic_columns_are_at_bounds() const;
void failed();
bool is_feasible() const;
const impq & get_value(unsigned j) const;
bool column_is_int_inf(unsigned j) const;
@ -122,11 +115,10 @@ private:
lp_settings& settings();
bool move_non_basic_columns_to_bounds();
void branch_infeasible_int_var(unsigned);
lia_move mk_gomory_cut(lar_term& t, mpq& k,explanation & ex, unsigned inf_col, const row_strip<mpq>& row);
lia_move report_conflict_from_gomory_cut(mpq & k);
void adjust_term_and_k_for_some_ints_case_gomory(lar_term& t, mpq& k, mpq& lcm_den);
void init_check_data();
lia_move proceed_with_gomory_cut(lar_term& t, mpq& k, explanation& ex, unsigned j, bool & upper);
lia_move mk_gomory_cut(unsigned inf_col, const row_strip<mpq>& row);
lia_move report_conflict_from_gomory_cut();
void adjust_term_and_k_for_some_ints_case_gomory(mpq& lcm_den);
lia_move proceed_with_gomory_cut(unsigned j);
int find_free_var_in_gomory_row(const row_strip<mpq>& );
bool is_gomory_cut_target(const row_strip<mpq>&);
bool at_bound(unsigned j) const;
@ -147,19 +139,19 @@ public:
return n.x - floor(n.x);
}
private:
void real_case_in_gomory_cut(const mpq & a, unsigned x_j, mpq & k, lar_term& t, explanation & ex, const mpq& f_0, const mpq& one_minus_f_0);
void int_case_in_gomory_cut(const mpq & a, unsigned x_j, mpq & k, lar_term& t, explanation& ex, mpq & lcm_den, const mpq& f_0, const mpq& one_minus_f_0);
void real_case_in_gomory_cut(const mpq & a, unsigned x_j, const mpq& f_0, const mpq& one_minus_f_0);
void int_case_in_gomory_cut(const mpq & a, unsigned x_j, mpq & lcm_den, const mpq& f_0, const mpq& one_minus_f_0);
constraint_index column_upper_bound_constraint(unsigned j) const;
constraint_index column_lower_bound_constraint(unsigned j) const;
void display_row_info(std::ostream & out, unsigned row_index) const;
void gomory_cut_adjust_t_and_k(vector<std::pair<mpq, unsigned>> & pol, lar_term & t, mpq &k, bool num_ints, mpq &lcm_den);
bool current_solution_is_inf_on_cut(const lar_term& t, const mpq& k) const;
bool current_solution_is_inf_on_cut() const;
public:
bool shift_var(unsigned j, unsigned range);
private:
unsigned random();
bool has_inf_int() const;
lia_move create_branch_on_column(int j, lar_term& t, mpq& k, bool free_column, bool & upper);
lia_move create_branch_on_column(int j);
void catch_up_in_adding_constraints_to_cut_solver();
public:
template <typename T>
@ -168,7 +160,7 @@ public:
void get_int_coeffs_from_constraint(const lar_base_constraint* c, vector<cut_solver::monomial>& coeff, T & rs);
bool is_term(unsigned j) const;
void add_constraint_to_cut_solver(unsigned,const lar_base_constraint*);
void copy_explanations_from_cut_solver(explanation &);
void copy_explanations_from_cut_solver();
void pop(unsigned);
void push();
void copy_values_from_cut_solver();
@ -177,5 +169,11 @@ public:
bool tighten_terms_for_cube();
bool tighten_term_for_cube(unsigned);
unsigned column_count() const;
bool all_columns_are_bounded() const;
impq get_cube_delta_for_term(const lar_term&) const;
void find_feasible_solution();
int find_inf_int_nbasis_column() const;
lia_move run_gcd_test();
lia_move call_cut_solver();
};
}