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z3/src/math/lp/monic.h
Nikolaj Bjorner fdedeed7ae additional sign related fix for #4740 https://github.com/Z3Prover/z3/issues/4740#issuecomment-721508240
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2020-11-10 10:50:13 -08:00

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C++

/*
Copyright (c) 2017 Microsoft Corporation
Author: Nikolaj Bjorner
Lev Nachmanson
A mon_eq represents a definition m_v = v1*v2*...*vn,
where m_vs = [v1, v2, .., vn]
A monic contains a mon_eq and variables in canonized form.
*/
#pragma once
#include "math/lp/lp_settings.h"
#include "util/vector.h"
#include "math/lp/lar_solver.h"
#include "math/lp/nla_defs.h"
#include <algorithm>
namespace nla {
class mon_eq {
// fields
lp::var_index m_v;
svector<lp::var_index> m_vs;
public:
// constructors
mon_eq(lp::var_index v, unsigned sz, lp::var_index const* vs):
m_v(v), m_vs(sz, vs) {
std::sort(m_vs.begin(), m_vs.end());
}
mon_eq(lp::var_index v, const svector<lp::var_index> &vs):
m_v(v), m_vs(vs) {
std::sort(m_vs.begin(), m_vs.end());
}
mon_eq(): m_v(UINT_MAX) {}
unsigned var() const { return m_v; }
unsigned size() const { return m_vs.size(); }
const svector<lp::var_index>& vars() const { return m_vs; }
bool empty() const { return m_vs.empty(); }
bool is_sorted() const {
for (unsigned i = 0; i + 1 < size(); i++)
if (m_vs[i] > m_vs[i + 1])
return false;
return true;
}
bool contains_var(lpvar j) const {
return std::binary_search(m_vs.begin(), m_vs.end(), j);
}
protected:
svector<lp::var_index>& vars1() { return m_vs; }
};
// support the congruence
class monic: public mon_eq {
// fields
svector<lpvar> m_rvars;
bool m_rsign;
mutable unsigned m_visited;
public:
// constructors
monic(lpvar v, unsigned sz, lpvar const* vs, unsigned idx):
monic(v, svector<lpvar>(sz, vs), idx) {}
monic(lpvar v, const svector<lpvar> &vs, unsigned idx):
mon_eq(v, vs), m_rsign(false), m_visited(0) {
std::sort(vars1().begin(), vars1().end());
}
unsigned visited() const { return m_visited; }
void set_visited(unsigned v) { m_visited = v; }
svector<lpvar> const& rvars() const { return m_rvars; }
bool rsign() const { return m_rsign; }
void reset_rfields() { m_rsign = false; m_rvars.reset(); SASSERT(m_rvars.size() == 0); }
void push_rvar(signed_var sv) { m_rsign ^= sv.sign(); m_rvars.push_back(sv.var()); }
void sort_rvars() { std::sort(m_rvars.begin(), m_rvars.end()); }
svector<lpvar>::const_iterator begin() const { return vars().begin(); }
svector<lpvar>::const_iterator end() const { return vars().end(); }
rational rat_sign() const { return m_rsign ? rational(-1) : rational(1); }
};
inline std::ostream& operator<<(std::ostream& out, monic const& m) {
return out << m.var() << " := " << m.vars()
<< " r ( " << (m.rsign()?"- ":"") << m.rvars() << ")";
}
typedef std::unordered_map<lpvar, rational> variable_map_type;
template <typename T>
bool check_assignment(T const& m, variable_map_type & vars);
template <typename K>
bool check_assignments(const K & monomimials,
const lp::lar_solver& s,
variable_map_type & vars);
} // end of namespace nla