Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/factor_rewriter.h

@@ -0,0 +1,78 @@
+/*++
+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