/**CFile****************************************************************
FileName [saigLoc.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Sequential AIG package.]
Synopsis [K-step induction for one property only.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: saigLoc.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "saig.h"
#include "sat/cnf/cnf.h"
#include "sat/bsat/satSolver.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Returns 1 if two state are equal.]
Description [Array vState contains indexes of CNF variables for each
flop in the first N time frames (0 < i < k, i < N, k < N).]
SideEffects []
SeeAlso []
***********************************************************************/
int Saig_ManStatesAreEqual( sat_solver * pSat, Vec_Int_t * vState, int nRegs, int i, int k )
{
int * pStateI = (int *)Vec_IntArray(vState) + nRegs * i;
int * pStateK = (int *)Vec_IntArray(vState) + nRegs * k;
int v;
assert( i && k && i < k );
assert( nRegs * k <= Vec_IntSize(vState) );
// check if the states are available
for ( v = 0; v < nRegs; v++ )
if ( pStateI[v] >= 0 && pStateK[v] == -1 )
return 0;
/*
printf( "\nchecking uniqueness\n" );
printf( "%3d : ", i );
for ( v = 0; v < nRegs; v++ )
printf( "%d", sat_solver_var_value(pSat, pStateI[v]) );
printf( "\n" );
printf( "%3d : ", k );
for ( v = 0; v < nRegs; v++ )
printf( "%d", sat_solver_var_value(pSat, pStateK[v]) );
printf( "\n" );
*/
for ( v = 0; v < nRegs; v++ )
if ( pStateI[v] >= 0 )
{
if ( sat_solver_var_value(pSat, pStateI[v]) != sat_solver_var_value(pSat, pStateK[v]) )
return 0;
}
return 1;
}
/**Function*************************************************************
Synopsis [Add uniqueness constraint.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Saig_ManAddUniqueness( sat_solver * pSat, Vec_Int_t * vState, int nRegs, int i, int k, int * pnSatVarNum, int * pnClauses, int fVerbose )
{
int * pStateI = (int *)Vec_IntArray(vState) + nRegs * i;
int * pStateK = (int *)Vec_IntArray(vState) + nRegs * k;
int v, iVars, nSatVarsOld, RetValue, * pClause;
assert( i && k && i < k );
assert( nRegs * k <= Vec_IntSize(vState) );
// check if the states are available
for ( v = 0; v < nRegs; v++ )
if ( pStateI[v] >= 0 && pStateK[v] == -1 )
{
if ( fVerbose )
printf( "Cannot constrain an incomplete state.\n" );
return 0;
}
// add XORs
nSatVarsOld = *pnSatVarNum;
for ( v = 0; v < nRegs; v++ )
if ( pStateI[v] >= 0 )
{
*pnClauses += 4;
RetValue = Cnf_DataAddXorClause( pSat, pStateI[v], pStateK[v], (*pnSatVarNum)++ );
if ( RetValue == 0 )
{
if ( fVerbose )
printf( "SAT solver became UNSAT after adding a uniqueness constraint.\n" );
return 1;
}
}
// add OR clause
(*pnClauses)++;
iVars = 0;
pClause = ABC_ALLOC( int, nRegs );
for ( v = nSatVarsOld; v < *pnSatVarNum; v++ )
pClause[iVars++] = toLitCond( v, 0 );
assert( iVars <= nRegs );
RetValue = sat_solver_addclause( pSat, pClause, pClause + iVars );
ABC_FREE( pClause );
if ( RetValue == 0 )
{
if ( fVerbose )
printf( "SAT solver became UNSAT after adding a uniqueness constraint.\n" );
return 1;
}
return 0;
}
/**Function*************************************************************
Synopsis [Performs induction by unrolling timeframes backward.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Saig_ManInduction( Aig_Man_t * p, int nTimeOut, int nFramesMax, int nConfMax, int fUnique, int fUniqueAll, int fGetCex, int fVerbose, int fVeryVerbose )
{
sat_solver * pSat;
Aig_Man_t * pAigPart = NULL;
Cnf_Dat_t * pCnfPart = NULL;
Vec_Int_t * vTopVarNums, * vState, * vTopVarIds = NULL;
Vec_Ptr_t * vTop, * vBot;
Aig_Obj_t * pObjPi, * pObjPiCopy, * pObjPo;
int i, k, f, Lits[2], status = -1, RetValue, nSatVarNum, nConfPrev;
int nOldSize, iReg, iLast, fAdded, nConstrs = 0, nClauses = 0;
abctime clk, nTimeToStop = nTimeOut ? nTimeOut * CLOCKS_PER_SEC + Abc_Clock() : 0;
assert( fUnique == 0 || fUniqueAll == 0 );
assert( Saig_ManPoNum(p) == 1 );
Aig_ManSetCioIds( p );
// start the top by including the PO
vBot = Vec_PtrAlloc( 100 );
vTop = Vec_PtrAlloc( 100 );
vState = Vec_IntAlloc( 1000 );
Vec_PtrPush( vTop, Aig_ManCo(p, 0) );
// start the array of CNF variables
vTopVarNums = Vec_IntAlloc( 100 );
// start the solver
pSat = sat_solver_new();
sat_solver_setnvars( pSat, 1000 );
// set runtime limit
if ( nTimeToStop )
sat_solver_set_runtime_limit( pSat, nTimeToStop );
// iterate backward unrolling
RetValue = -1;
nSatVarNum = 0;
if ( fVerbose )
printf( "Induction parameters: FramesMax = %5d. ConflictMax = %6d.\n", nFramesMax, nConfMax );
for ( f = 0; ; f++ )
{
if ( f > 0 )
{
Aig_ManStop( pAigPart );
Cnf_DataFree( pCnfPart );
}
clk = Abc_Clock();
// get the bottom
Aig_SupportNodes( p, (Aig_Obj_t **)Vec_PtrArray(vTop), Vec_PtrSize(vTop), vBot );
// derive AIG for the part between top and bottom
pAigPart = Aig_ManDupSimpleDfsPart( p, vBot, vTop );
// convert it into CNF
pCnfPart = Cnf_Derive( pAigPart, Aig_ManCoNum(pAigPart) );
Cnf_DataLift( pCnfPart, nSatVarNum );
nSatVarNum += pCnfPart->nVars;
nClauses += pCnfPart->nClauses;
// remember top frame var IDs
if ( fGetCex && vTopVarIds == NULL )
{
vTopVarIds = Vec_IntStartFull( Aig_ManCiNum(p) );
Aig_ManForEachCi( p, pObjPi, i )
{
if ( pObjPi->pData == NULL )
continue;
pObjPiCopy = (Aig_Obj_t *)pObjPi->pData;
assert( Aig_ObjIsCi(pObjPiCopy) );
if ( Saig_ObjIsPi(p, pObjPi) )
Vec_IntWriteEntry( vTopVarIds, Aig_ObjCioId(pObjPi) + Saig_ManRegNum(p), pCnfPart->pVarNums[Aig_ObjId(pObjPiCopy)] );
else if ( Saig_ObjIsLo(p, pObjPi) )
Vec_IntWriteEntry( vTopVarIds, Aig_ObjCioId(pObjPi) - Saig_ManPiNum(p), pCnfPart->pVarNums[Aig_ObjId(pObjPiCopy)] );
else assert( 0 );
}
}
// stitch variables of top and bot
assert( Aig_ManCoNum(pAigPart)-1 == Vec_IntSize(vTopVarNums) );
Aig_ManForEachCo( pAigPart, pObjPo, i )
{
if ( i == 0 )
{
// do not perform inductive strengthening
// if ( f > 0 )
// continue;
// add topmost literal
Lits[0] = toLitCond( pCnfPart->pVarNums[pObjPo->Id], f>0 );
if ( !sat_solver_addclause( pSat, Lits, Lits+1 ) )
assert( 0 );
nClauses++;
continue;
}
Lits[0] = toLitCond( Vec_IntEntry(vTopVarNums, i-1), 0 );
Lits[1] = toLitCond( pCnfPart->pVarNums[pObjPo->Id], 1 );
if ( !sat_solver_addclause( pSat, Lits, Lits+2 ) )
assert( 0 );
Lits[0] = toLitCond( Vec_IntEntry(vTopVarNums, i-1), 1 );
Lits[1] = toLitCond( pCnfPart->pVarNums[pObjPo->Id], 0 );
if ( !sat_solver_addclause( pSat, Lits, Lits+2 ) )
assert( 0 );
nClauses += 2;
}
// add CNF to the SAT solver
for ( i = 0; i < pCnfPart->nClauses; i++ )
if ( !sat_solver_addclause( pSat, pCnfPart->pClauses[i], pCnfPart->pClauses[i+1] ) )
break;
if ( i < pCnfPart->nClauses )
{
// printf( "SAT solver became UNSAT after adding clauses.\n" );
RetValue = 1;
break;
}
// create new set of POs to derive new top
Vec_PtrClear( vTop );
Vec_PtrPush( vTop, Aig_ManCo(p, 0) );
Vec_IntClear( vTopVarNums );
nOldSize = Vec_IntSize(vState);
Vec_IntFillExtra( vState, nOldSize + Aig_ManRegNum(p), -1 );
Vec_PtrForEachEntry( Aig_Obj_t *, vBot, pObjPi, i )
{
assert( Aig_ObjIsCi(pObjPi) );
if ( Saig_ObjIsLo(p, pObjPi) )
{
pObjPiCopy = (Aig_Obj_t *)pObjPi->pData;
assert( pObjPiCopy != NULL );
Vec_PtrPush( vTop, Saig_ObjLoToLi(p, pObjPi) );
Vec_IntPush( vTopVarNums, pCnfPart->pVarNums[pObjPiCopy->Id] );
iReg = pObjPi->CioId - Saig_ManPiNum(p);
assert( iReg >= 0 && iReg < Aig_ManRegNum(p) );
Vec_IntWriteEntry( vState, nOldSize+iReg, pCnfPart->pVarNums[pObjPiCopy->Id] );
}
}
assert( Vec_IntSize(vState)%Aig_ManRegNum(p) == 0 );
iLast = Vec_IntSize(vState)/Aig_ManRegNum(p);
if ( fUniqueAll )
{
for ( i = 1; i < iLast-1; i++ )
{
nConstrs++;
if ( fVeryVerbose )
printf( "Adding constaint for state %2d and state %2d.\n", i, iLast-1 );
if ( Saig_ManAddUniqueness( pSat, vState, Aig_ManRegNum(p), i, iLast-1, &nSatVarNum, &nClauses, fVerbose ) )
break;
}
if ( i < iLast-1 )
{
RetValue = 1;
break;
}
}
nextrun:
fAdded = 0;
// run the SAT solver
nConfPrev = pSat->stats.conflicts;
status = sat_solver_solve( pSat, NULL, NULL, (ABC_INT64_T)nConfMax, 0, 0, 0 );
if ( fVerbose )
{
printf( "Frame %4d : PI =%5d. PO =%5d. AIG =%5d. Var =%7d. Clau =%7d. Conf =%7d. ",
f, Aig_ManCiNum(pAigPart), Aig_ManCoNum(pAigPart), Aig_ManNodeNum(pAigPart),
nSatVarNum, nClauses, (int)pSat->stats.conflicts-nConfPrev );
ABC_PRT( "Time", Abc_Clock() - clk );
}
if ( status == l_Undef )
break;
if ( status == l_False )
{
RetValue = 1;
break;
}
assert( status == l_True );
// the problem is SAT - add more clauses
if ( fVeryVerbose )
{
Vec_IntForEachEntry( vState, iReg, i )
{
if ( i && (i % Aig_ManRegNum(p)) == 0 )
printf( "\n" );
if ( (i % Aig_ManRegNum(p)) == 0 )
printf( " State %3d : ", i/Aig_ManRegNum(p) );
printf( "%c", (iReg >= 0) ? ('0' + sat_solver_var_value(pSat, iReg)) : 'x' );
}
printf( "\n" );
}
if ( nFramesMax && f == nFramesMax - 1 )
{
// derive counter-example
assert( status == l_True );
if ( fGetCex )
{
int VarNum, iBit = 0;
Abc_Cex_t * pCex = Abc_CexAlloc( Aig_ManRegNum(p)-1, Saig_ManPiNum(p), 1 );
pCex->iFrame = 0;
pCex->iPo = 0;
Vec_IntForEachEntryStart( vTopVarIds, VarNum, i, 1 )
{
if ( VarNum >= 0 && sat_solver_var_value( pSat, VarNum ) )
Abc_InfoSetBit( pCex->pData, iBit );
iBit++;
}
assert( iBit == pCex->nBits );
Abc_CexFree( p->pSeqModel );
p->pSeqModel = pCex;
}
break;
}
if ( fUnique )
{
for ( i = 1; i < iLast; i++ )
{
for ( k = i+1; k < iLast; k++ )
{
if ( !Saig_ManStatesAreEqual( pSat, vState, Aig_ManRegNum(p), i, k ) )
continue;
nConstrs++;
fAdded = 1;
if ( fVeryVerbose )
printf( "Adding constaint for state %2d and state %2d.\n", i, k );
if ( Saig_ManAddUniqueness( pSat, vState, Aig_ManRegNum(p), i, k, &nSatVarNum, &nClauses, fVerbose ) )
break;
}
if ( k < iLast )
break;
}
if ( i < iLast )
{
RetValue = 1;
break;
}
}
if ( fAdded )
goto nextrun;
}
if ( fVerbose )
{
if ( nTimeToStop && Abc_Clock() >= nTimeToStop )
printf( "Timeout (%d sec) was reached during iteration %d.\n", nTimeOut, f+1 );
else if ( status == l_Undef )
printf( "Conflict limit (%d) was reached during iteration %d.\n", nConfMax, f+1 );
else if ( fUnique || fUniqueAll )
printf( "Completed %d interations and added %d uniqueness constraints.\n", f+1, nConstrs );
else
printf( "Completed %d interations.\n", f+1 );
}
// cleanup
sat_solver_delete( pSat );
Aig_ManStop( pAigPart );
Cnf_DataFree( pCnfPart );
Vec_IntFree( vTopVarNums );
Vec_PtrFree( vTop );
Vec_PtrFree( vBot );
Vec_IntFree( vState );
Vec_IntFreeP( &vTopVarIds );
return RetValue;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END