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z3/lib/factor_rewriter.h
Leonardo de Moura e9eab22e5c Z3 sources
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2012-10-02 11:35:25 -07:00

79 lines
2.3 KiB
C++

/*++
Copyright (c) 2011 Microsoft Corporation
Module Name:
factor_rewriter.h
Abstract:
Rewriting utilities for factoring polynomials in equations,
and inequalities.
Author:
Nikolaj (nbjorner) 2011-19-05
Notes:
--*/
#ifndef _FACTOR_REWRITER_H_
#define _FACTOR_REWRITER_H_
#include"ast.h"
#include"rewriter.h"
#include"arith_decl_plugin.h"
class factor_rewriter {
typedef obj_map<expr,unsigned> powers_t;
ast_manager & m_manager;
arith_util m_arith;
powers_t m_powers;
vector<std::pair<expr*,bool> > m_adds;
vector<ptr_vector<expr> > m_muls;
expr_ref_vector m_factors;
public:
factor_rewriter(ast_manager & m);
ast_manager & m() const { return m_manager; }
arith_util & a() { return m_arith; }
br_status mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result);
private:
br_status mk_eq(expr * arg1, expr * arg2, expr_ref & result);
br_status mk_le(expr * arg1, expr * arg2, expr_ref & result);
br_status mk_lt(expr * arg1, expr * arg2, expr_ref & result);
br_status mk_ge(expr * a1, expr * a2, expr_ref & r) { return mk_le(a2,a1,r); }
br_status mk_gt(expr * a1, expr * a2, expr_ref & r) { return mk_lt(a2,a1,r); }
void mk_adds(expr* arg1, expr* arg2);
void mk_muls();
void mk_expand_muls(ptr_vector<expr>& muls);
void collect_powers();
bool extract_factors();
bool even(unsigned n) const { return 0 == (n & 0x1); }
void mk_is_negative(expr_ref& result, expr_ref_vector& eqs);
};
struct factor_rewriter_cfg : public default_rewriter_cfg {
factor_rewriter m_r;
bool rewrite_patterns() const { return false; }
bool flat_assoc(func_decl * f) const { return false; }
br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
result_pr = 0;
return m_r.mk_app_core(f, num, args, result);
}
factor_rewriter_cfg(ast_manager & m):m_r(m) {}
};
class factor_rewriter_star : public rewriter_tpl<factor_rewriter_cfg> {
factor_rewriter_cfg m_cfg;
public:
factor_rewriter_star(ast_manager & m):
rewriter_tpl<factor_rewriter_cfg>(m, false, m_cfg),
m_cfg(m) {}
};
#endif