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/**CFile****************************************************************
FileName [giaCCof.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Scalable AIG package.]
Synopsis [Backward reachability using circuit cofactoring.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: giaCCof.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "gia.h"
#include "satSolver.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
typedef struct Ccf_Man_t_ Ccf_Man_t; // manager
struct Ccf_Man_t_
{
// user data
Gia_Man_t * pGia; // single output AIG manager
int nFrameMax; // maximum number of frames
int nConfMax; // maximum number of conflicts
int nTimeMax; // maximum runtime in seconds
int fVerbose; // verbose flag
// internal data
sat_solver * pSat; // SAT solver
Gia_Man_t * pFrames; // unrolled timeframes
Vec_Int_t * vIdToFra; // maps GIA obj IDs into frame obj IDs
Vec_Int_t * vOrder; // map Num to Id
Vec_Int_t * vFraLims; // frame limits
};
extern Vec_Int_t * Gia_VtaCollect( Gia_Man_t * p, Vec_Int_t ** pvFraLims, Vec_Int_t ** pvRoots );
static inline int Gia_ObjFrames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { assert( Vec_IntEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj)) >= 0 ); return Vec_IntEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj)); }
static inline void Gia_ObjSetFrames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj, int Lit ) { Vec_IntWriteEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj), Lit); }
static inline int Gia_ObjChild0Frames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { return Gia_LitNotCond(Gia_ObjFrames(p, f, Gia_ObjFanin0(pObj)), Gia_ObjFaninC0(pObj)); }
static inline int Gia_ObjChild1Frames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { return Gia_LitNotCond(Gia_ObjFrames(p, f, Gia_ObjFanin1(pObj)), Gia_ObjFaninC1(pObj)); }
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
static inline int sat_solver_add_const( sat_solver * pSat, int iVar, int fCompl )
{
lit Lits[1];
int Cid;
assert( iVar >= 0 );
Lits[0] = toLitCond( iVar, fCompl );
Cid = sat_solver_addclause( pSat, Lits, Lits + 1 );
assert( Cid );
return 1;
}
static inline int sat_solver_add_buffer( sat_solver * pSat, int iVarA, int iVarB, int fCompl )
{
lit Lits[2];
int Cid;
assert( iVarA >= 0 && iVarB >= 0 );
Lits[0] = toLitCond( iVarA, 0 );
Lits[1] = toLitCond( iVarB, !fCompl );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
Lits[0] = toLitCond( iVarA, 1 );
Lits[1] = toLitCond( iVarB, fCompl );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
return 2;
}
static inline int sat_solver_add_and( sat_solver * pSat, int iVar, int iVar0, int iVar1, int fCompl0, int fCompl1 )
{
lit Lits[3];
int Cid;
Lits[0] = toLitCond( iVar, 1 );
Lits[1] = toLitCond( iVar0, fCompl0 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
Lits[0] = toLitCond( iVar, 1 );
Lits[1] = toLitCond( iVar1, fCompl1 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
Lits[0] = toLitCond( iVar, 0 );
Lits[1] = toLitCond( iVar0, !fCompl0 );
Lits[2] = toLitCond( iVar1, !fCompl1 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
assert( Cid );
return 3;
}
static inline int sat_solver_add_xor( sat_solver * pSat, int iVarA, int iVarB, int iVarC, int fCompl )
{
lit Lits[3];
int Cid;
assert( iVarA >= 0 && iVarB >= 0 && iVarC >= 0 );
Lits[0] = toLitCond( iVarA, !fCompl );
Lits[1] = toLitCond( iVarB, 1 );
Lits[2] = toLitCond( iVarC, 1 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
assert( Cid );
Lits[0] = toLitCond( iVarA, !fCompl );
Lits[1] = toLitCond( iVarB, 0 );
Lits[2] = toLitCond( iVarC, 0 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
assert( Cid );
Lits[0] = toLitCond( iVarA, fCompl );
Lits[1] = toLitCond( iVarB, 1 );
Lits[2] = toLitCond( iVarC, 0 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
assert( Cid );
Lits[0] = toLitCond( iVarA, fCompl );
Lits[1] = toLitCond( iVarB, 0 );
Lits[2] = toLitCond( iVarC, 1 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
assert( Cid );
return 4;
}
static inline int sat_solver_add_constraint( sat_solver * pSat, int iVar, int fCompl )
{
lit Lits[2];
int Cid;
assert( iVar >= 0 );
Lits[0] = toLitCond( iVar, fCompl );
Lits[1] = toLitCond( iVar+1, 0 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
Lits[0] = toLitCond( iVar, fCompl );
Lits[1] = toLitCond( iVar+1, 1 );
Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
assert( Cid );
return 2;
}
/**Function*************************************************************
Synopsis [Create manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Ccf_Man_t * Ccf_ManStart( Gia_Man_t * pGia, int nFrameMax, int nConfMax, int nTimeMax, int fVerbose )
{
Ccf_Man_t * p;
assert( nFrameMax > 0 );
p = ABC_CALLOC( Ccf_Man_t, 1 );
p->pGia = pGia;
p->nFrameMax = nFrameMax;
p->nConfMax = nConfMax;
p->nTimeMax = nTimeMax;
p->fVerbose = fVerbose;
// internal data
p->pFrames = Gia_ManStart( 10000 );
Gia_ManHashAlloc( p->pFrames );
p->vOrder = Gia_VtaCollect( pGia, &p->vFraLims, NULL );
p->vIdToFra = Vec_IntAlloc( 0 );
p->pSat = sat_solver_new();
sat_solver_setnvars( p->pSat, 10000 );
return p;
}
/**Function*************************************************************
Synopsis [Delete manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ccf_ManStop( Ccf_Man_t * p )
{
Vec_IntFreeP( &p->vIdToFra );
Vec_IntFreeP( &p->vOrder );
Vec_IntFreeP( &p->vFraLims );
sat_solver_delete( p->pSat );
Gia_ManStopP( &p->pFrames );
ABC_FREE( p );
}
/**Function*************************************************************
Synopsis [Extends the solver.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Gia_ManCofExtendSolver( Ccf_Man_t * p )
{
Gia_Obj_t * pObj;
int i;
// add SAT clauses
for ( i = sat_solver_nvars(p->pSat); i < Gia_ManObjNum(p->pFrames); i++ )
{
pObj = Gia_ManObj( p->pGia, i );
if ( Gia_ObjIsAnd(pObj) )
sat_solver_add_and( p->pSat, i,
Gia_ObjFaninId0(pObj, i),
Gia_ObjFaninId1(pObj, i),
Gia_ObjFaninC0(pObj),
Gia_ObjFaninC1(pObj) );
}
}
/**Function*************************************************************
Synopsis [Adds logic of one timeframe to the manager.]
Description [Returns literal of the property output.]
SideEffects []
SeeAlso []
***********************************************************************/
int Gia_ManCofAddTimeFrame( Ccf_Man_t * p, int fMax )
{
Gia_Obj_t * pObj;
int i, f, Beg, End, Lit;
assert( fMax > 0 && fMax <= p->nFrameMax );
assert( Vec_IntSize(p->vIdToFra) == (fMax - 1) * Gia_ManObjNum(p->pGia) );
// add to the mapping of nodes
Vec_IntFillExtra( p->vIdToFra, fMax * Gia_ManObjNum(p->pGia), -1 );
// add nodes to each time-frame
for ( f = 0; f < fMax; f++ )
{
if ( Vec_IntSize(p->vFraLims) >= fMax-f )
continue;
Beg = Vec_IntEntry( p->vFraLims, fMax-f-1 );
End = Vec_IntEntry( p->vFraLims, fMax-f );
for ( i = Beg; i < End; i++ )
{
pObj = Gia_ManObj( p->pGia, Vec_IntEntry(p->vOrder, i) );
if ( Gia_ObjIsAnd(pObj) )
Lit = Gia_ManHashAnd( p->pFrames, Gia_ObjChild0Frames(p, f, pObj), Gia_ObjChild1Frames(p, f, pObj) );
else if ( Gia_ObjIsRo(p->pGia, pObj) && f > 0 )
Lit = Gia_ObjChild0Frames(p, f-1, Gia_ObjRoToRi(p->pGia, pObj));
else if ( Gia_ObjIsCi(pObj) )
{
Lit = Gia_ManAppendCi(p->pFrames);
// mark primary input
Gia_ManObj(p->pFrames, Gia_Lit2Var(Lit))->fMark0 = Gia_ObjIsPi(p->pGia, pObj);
}
else assert( 0 );
Gia_ObjSetFrames( p, f, pObj, Lit );
}
}
// add SAT clauses
Gia_ManCofExtendSolver( p );
// return output literal
return Gia_ObjChild0Frames( p, fMax-1, Gia_ManPo(p->pGia, 0) );
}
/**Function*************************************************************
Synopsis [Cofactor the circuit w.r.t. the given assignment.]
Description [Assumes that the solver has just returned SAT.]
SideEffects []
SeeAlso []
***********************************************************************/
int Gia_ManCofOneDerive_rec( Ccf_Man_t * p, Gia_Obj_t * pObj )
{
if ( ~pObj->Value )
return pObj->Value;
assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
if ( Gia_ObjIsAnd(pObj) )
{
Gia_ManCofOneDerive_rec( p, Gia_ObjFanin0(pObj) );
Gia_ManCofOneDerive_rec( p, Gia_ObjFanin1(pObj) );
pObj->Value = Gia_ManHashAnd( p->pFrames, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
}
else if ( pObj->fMark0 ) // PI
pObj->Value = sat_solver_var_value( p->pSat, Gia_ObjId(p->pGia, pObj) );
else
pObj->Value = Gia_Var2Lit( Gia_ObjId(p->pGia, pObj), 0 );
return pObj->Value;
}
/**Function*************************************************************
Synopsis [Cofactor the circuit w.r.t. the given assignment.]
Description [Assumes that the solver has just returned SAT.]
SideEffects []
SeeAlso []
***********************************************************************/
int Gia_ManCofOneDerive( Ccf_Man_t * p, int LitProp )
{
Gia_Obj_t * pObj;
int LitOut;
// get the property node
pObj = Gia_ManObj( p->pFrames, Gia_Lit2Var(LitProp) );
// derive the cofactor
Gia_ManFillValue( p->pFrames );
LitOut = Gia_ManCofOneDerive_rec( p, pObj );
LitOut = Gia_LitNotCond(LitOut, Gia_LitIsCompl(LitProp));
// add new PO for the cofactor
Gia_ManAppendCo( p->pFrames, LitOut );
// add SAT clauses
Gia_ManCofExtendSolver( p );
// return negative literal of the cofactor
return Gia_LitNot(LitOut);
}
/**Function*************************************************************
Synopsis [Enumerates backward reachable states.]
Description [Return -1 if resource limit is reached. Returns 1
if computation converged (there is no more reachable states).
Returns 0 if no more states to enumerate.]
SideEffects []
SeeAlso []
***********************************************************************/
int Gia_ManCofGetReachable( Ccf_Man_t * p, int Lit )
{
int RetValue;
// try solving for the first time and quit if converged
RetValue = sat_solver_solve( p->pSat, &Lit, &Lit + 1, p->nConfMax, 0, 0, 0 );
if ( RetValue == l_False )
return 1;
// iterate circuit cofactoring
while ( RetValue == 0 )
{
// derive cofactor
int LitOut = Gia_ManCofOneDerive( p, Lit );
// add the blocking clause
RetValue = sat_solver_addclause( p->pSat, &LitOut, &LitOut + 1 );
assert( RetValue );
// try solving again
RetValue = sat_solver_solve( p->pSat, &Lit, &Lit + 1, p->nConfMax, 0, 0, 0 );
}
if ( RetValue == l_Undef )
return -1;
return 0;
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Gia_Man_t * Gia_ManCofTest( Gia_Man_t * pGia, int nFrameMax, int nConfMax, int nTimeMax, int fVerbose )
{
Gia_Man_t * pNew;
Ccf_Man_t * p;
int f, Lit, RetValue;
assert( Gia_ManPoNum(pGia) == 1 );
// create reachability manager
p = Ccf_ManStart( pGia, nFrameMax, nConfMax, nTimeMax, fVerbose );
// perform backward image computation
for ( f = 0; f < nFrameMax; f++ )
{
if ( fVerbose )
printf( "ITER %3d :\n", f );
// derives new timeframe and returns the property literal
Lit = Gia_ManCofAddTimeFrame( p, f+1 );
// derives cofactors of the property literal till all states are blocked
RetValue = Gia_ManCofGetReachable( p, Lit );
if ( RetValue )
break;
}
// report the result
if ( f == nFrameMax )
printf( "Completed %d frames without converging.\n", f );
else if ( RetValue == 1 )
printf( "Backward reachability converged after %d iterations.\n", f );
else if ( RetValue == -1 )
printf( "Conflict limit or timeout is reached after %d frames.\n", f );
// get the resulting AIG manager
Gia_ManHashStop( p->pFrames );
Gia_ManCleanMark0( p->pFrames );
pNew = p->pFrames; p->pFrames = NULL;
Ccf_ManStop( p );
pNew = Gia_ManCleanup( pGia = pNew );
Gia_ManStop( pGia );
// if ( fVerbose )
Gia_ManPrintStats( pNew, 0 );
return pNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
|
