mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-10-01 13:39:28 +00:00
Code Activity

merge LRA

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-05-09 10:46:11 -07:00
parent 085d31dca2
commit 911b24784a
120 changed files with 23069 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

77
src/util/lp/random_updater.h Normal file
View file

@ -0,0 +1,77 @@
/*
Copyright (c) 2017 Microsoft Corporation
Author: Lev Nachmanson
*/
#pragma once
#include <set>
#include "util/vector.h"
#include <unordered_map>
#include <string>
#include <algorithm>
#include "util/lp/lp_settings.h"
#include "util/lp/linear_combination_iterator.h"
// see http://research.microsoft.com/projects/z3/smt07.pdf
// The class searches for a feasible solution with as many different values of variables as it can find
namespace lean {
template <typename T> struct numeric_pair; // forward definition
class lar_core_solver; // forward definition
class random_updater {
unsigned range = 100000;
struct interval {
bool upper_bound_is_set = false;
numeric_pair<mpq> upper_bound;
bool low_bound_is_set = false;
numeric_pair<mpq> low_bound;
void set_low_bound(const numeric_pair<mpq> & v) {
if (low_bound_is_set) {
low_bound = std::max(v, low_bound);
} else {
low_bound = v;
low_bound_is_set = true;
}
}
void set_upper_bound(const numeric_pair<mpq> & v) {
if (upper_bound_is_set) {
upper_bound = std::min(v, upper_bound);
} else {
upper_bound = v;
upper_bound_is_set = true;
}
}
bool is_empty() const {return
upper_bound_is_set && low_bound_is_set && low_bound >= upper_bound;
}
bool low_bound_holds(const numeric_pair<mpq> & a) const {
return low_bound_is_set == false || a >= low_bound;
}
bool upper_bound_holds(const numeric_pair<mpq> & a) const {
return upper_bound_is_set == false || a <= upper_bound;
}
bool contains(const numeric_pair<mpq> & a) const {
return low_bound_holds(a) && upper_bound_holds(a);
}
std::string lbs() { return low_bound_is_set ? T_to_string(low_bound):std::string("inf");}
std::string rbs() { return upper_bound_is_set? T_to_string(upper_bound):std::string("inf");}
std::string to_str() { return std::string("[")+ lbs() + ", " + rbs() + "]";}
};
std::set<var_index> m_var_set;
lar_core_solver & m_core_solver;
linear_combination_iterator<mpq>* m_column_j; // the actual column
interval find_shift_interval(unsigned j);
interval get_interval_of_non_basic_var(unsigned j);
void add_column_to_sets(unsigned j);
void random_shift_var(unsigned j);
std::unordered_map<numeric_pair<mpq>, unsigned> m_values; // it maps a value to the number of time it occurs
void diminish_interval_to_leave_basic_vars_feasible(numeric_pair<mpq> &nb_x, interval & inter);
void shift_var(unsigned j, interval & r);
void diminish_interval_for_basic_var(numeric_pair<mpq> &nb_x, unsigned j, mpq & a, interval & r);
numeric_pair<mpq> get_random_from_interval(interval & r);
void add_value(numeric_pair<mpq>& v);
void remove_value(numeric_pair<mpq> & v);
public:
random_updater(lar_core_solver & core_solver, const vector<unsigned> & column_list);
void update();
};
}