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/********************* */
/*! \file fun_def_process.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Pre-process step for admissible recursively defined functions
**/
#include "cvc4_private.h"
#ifndef __CVC4__QUANTIFIERS_FUN_DEF_PROCESS_H
#define __CVC4__QUANTIFIERS_FUN_DEF_PROCESS_H
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include "expr/node.h"
#include "expr/type_node.h"
namespace CVC4 {
namespace theory {
namespace quantifiers {
//Preprocessing pass to allow finite model finding for admissible recursive function definitions
// For details, see Reynolds et al "Model Finding for Recursive Functions" IJCAR 2016
class FunDefFmf {
private:
/** simplify formula
* This is A_0 in Figure 1 of Reynolds et al "Model Finding for Recursive Functions".
* The input of A_0 in that paper is a pair ( term t, polarity p )
* The return value of A_0 in that paper is a pair ( term t', set of formulas X ).
*
* This function implements this such that :
* n is t
* pol/hasPol is p
* the return value is t'
* the set of formulas X are stored in "constraints"
*
* Additionally, is_fun_def is whether we are currently processing the top of a function defintion,
* since this affects whether we process the head of the definition.
*/
Node simplifyFormula( Node n, bool pol, bool hasPol, std::vector< Node >& constraints, Node hd, bool is_fun_def,
std::map< int, std::map< Node, Node > >& visited,
std::map< int, std::map< Node, Node > >& visited_cons );
public:
FunDefFmf(){}
~FunDefFmf(){}
//defined functions to input sort (alpha)
std::map< Node, TypeNode > d_sorts;
//defined functions to injections input -> argument elements (gamma)
std::map< Node, std::vector< Node > > d_input_arg_inj;
// (newly) defined functions
std::vector< Node > d_funcs;
/** simplify, which does the following:
* (1) records all top-level recursive function definitions in assertions,
* (2) runs Figure 1 of Reynolds et al "Model Finding for Recursive Functions"
* IJCAR 2016 on all formulas in assertions based on the definitions from part (1),
* which are Sigma^{dfn} in that paper.
*/
void simplify( std::vector< Node >& assertions );
/** get constraints
*
* This computes constraints for the final else branch of A_0 in Figure 1
* of Reynolds et al "Model Finding for Recursive Functions". The range of
* the cache visited stores the constraint (if any) for each node.
*/
void getConstraints(Node n,
std::vector<Node>& constraints,
std::map<Node, Node>& visited);
};
}
}
}
#endif
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