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/**CFile****************************************************************
FileName [llb2Cex.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [BDD based reachability.]
Synopsis [Non-linear quantification scheduling.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: llb2Cex.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "llbInt.h"
#include "cnf.h"
#include "satSolver.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Translates a sequence of states into a counter-example.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Cex_t * Llb4_Nonlin4TransformCex( Aig_Man_t * pAig, Vec_Ptr_t * vStates, int fVerbose )
{
Abc_Cex_t * pCex;
Cnf_Dat_t * pCnf;
Vec_Int_t * vAssumps;
sat_solver * pSat;
Aig_Obj_t * pObj;
unsigned * pNext, * pThis;
int i, k, iBit, status, nRegs, clk = clock();
/*
Vec_PtrForEachEntry( unsigned *, vStates, pNext, i )
{
printf( "%4d : ", i );
Extra_PrintBinary( stdout, pNext, Aig_ManRegNum(pAig) );
printf( "\n" );
}
*/
// derive SAT solver
nRegs = Aig_ManRegNum(pAig); pAig->nRegs = 0;
pCnf = Cnf_Derive( pAig, Aig_ManPoNum(pAig) );
pAig->nRegs = nRegs;
// Cnf_DataTranformPolarity( pCnf, 0 );
// convert into SAT solver
pSat = (sat_solver *)Cnf_DataWriteIntoSolver( pCnf, 1, 0 );
if ( pSat == NULL )
{
printf( "Llb4_Nonlin4TransformCex(): Counter-example generation has failed.\n" );
Cnf_DataFree( pCnf );
return NULL;
}
// simplify the problem
status = sat_solver_simplify(pSat);
if ( status == 0 )
{
printf( "Llb4_Nonlin4TransformCex(): SAT solver is invalid.\n" );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
return NULL;
}
// start the counter-example
pCex = Abc_CexAlloc( Saig_ManRegNum(pAig), Saig_ManPiNum(pAig), Vec_PtrSize(vStates) );
pCex->iFrame = Vec_PtrSize(vStates)-1;
pCex->iPo = -1;
// solve each time frame
iBit = Saig_ManRegNum(pAig);
pThis = Vec_PtrEntry( vStates, 0 );
vAssumps = Vec_IntAlloc( 2 * Aig_ManRegNum(pAig) );
Vec_PtrForEachEntryStart( unsigned *, vStates, pNext, i, 1 )
{
// create assumptions
Vec_IntClear( vAssumps );
Saig_ManForEachLo( pAig, pObj, k )
Vec_IntPush( vAssumps, toLitCond( pCnf->pVarNums[Aig_ObjId(pObj)], !Aig_InfoHasBit(pThis,k) ) );
Saig_ManForEachLi( pAig, pObj, k )
Vec_IntPush( vAssumps, toLitCond( pCnf->pVarNums[Aig_ObjId(pObj)], !Aig_InfoHasBit(pNext,k) ) );
// solve SAT problem
status = sat_solver_solve( pSat, Vec_IntArray(vAssumps), Vec_IntArray(vAssumps) + Vec_IntSize(vAssumps),
(ABC_INT64_T)0, (ABC_INT64_T)0, (ABC_INT64_T)0, (ABC_INT64_T)0 );
// if the problem is SAT, get the counterexample
if ( status != l_True )
{
printf( "Llb4_Nonlin4TransformCex(): There is no transition between state %d and %d.\n", i-1, i );
Vec_IntFree( vAssumps );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
ABC_FREE( pCex );
return NULL;
}
// get the assignment of PIs
Saig_ManForEachPi( pAig, pObj, k )
if ( sat_solver_var_value(pSat, pCnf->pVarNums[Aig_ObjId(pObj)]) )
Aig_InfoSetBit( pCex->pData, iBit + k );
// update the counter
iBit += Saig_ManPiNum(pAig);
pThis = pNext;
}
// add the last frame when the property fails
Vec_IntClear( vAssumps );
Saig_ManForEachPo( pAig, pObj, k )
Vec_IntPush( vAssumps, toLitCond( pCnf->pVarNums[Aig_ObjId(pObj)], 0 ) );
// add clause
status = sat_solver_addclause( pSat, Vec_IntArray(vAssumps), Vec_IntArray(vAssumps) + Vec_IntSize(vAssumps) );
if ( status == 0 )
{
printf( "Llb4_Nonlin4TransformCex(): The SAT solver is unsat after adding last clause.\n" );
Vec_IntFree( vAssumps );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
ABC_FREE( pCex );
return NULL;
}
// create assumptions
Vec_IntClear( vAssumps );
Saig_ManForEachLo( pAig, pObj, k )
Vec_IntPush( vAssumps, toLitCond( pCnf->pVarNums[Aig_ObjId(pObj)], !Aig_InfoHasBit(pThis,k) ) );
// solve the last frame
status = sat_solver_solve( pSat, Vec_IntArray(vAssumps), Vec_IntArray(vAssumps) + Vec_IntSize(vAssumps),
(ABC_INT64_T)0, (ABC_INT64_T)0, (ABC_INT64_T)0, (ABC_INT64_T)0 );
if ( status != l_True )
{
printf( "Llb4_Nonlin4TransformCex(): There is no last transition that makes the property fail.\n" );
Vec_IntFree( vAssumps );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
ABC_FREE( pCex );
return NULL;
}
// get the assignment of PIs
Saig_ManForEachPi( pAig, pObj, k )
if ( sat_solver_var_value(pSat, pCnf->pVarNums[Aig_ObjId(pObj)]) )
Aig_InfoSetBit( pCex->pData, iBit + k );
iBit += Saig_ManPiNum(pAig);
assert( iBit == pCex->nBits );
// free the sat_solver
Vec_IntFree( vAssumps );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
// verify counter-example
status = Saig_ManFindFailedPoCex( pAig, pCex );
if ( status >= 0 && status < Saig_ManPoNum(pAig) )
pCex->iPo = status;
else
{
printf( "Inter_ManGetCounterExample(): Counter-example verification has FAILED.\n" );
ABC_FREE( pCex );
return NULL;
}
// report the results
// if ( fVerbose )
// Abc_PrintTime( 1, "SAT-based cex generation time", clock() - clk );
return pCex;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
|
