/**Function*************************************************************
Synopsis [Computes initial values of the new latches.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Abc_NtkRetimeInitialValues( Abc_Ntk_t * pNtkCone, Vec_Int_t * vValues, int fVerbose )
{
Vec_Int_t * vSolution;
Abc_Ntk_t * pNtkMiter, * pNtkLogic;
int RetValue;
abctime clk;
if ( pNtkCone == NULL )
return Vec_IntDup( vValues );
// convert the target network to AIG
pNtkLogic = Abc_NtkDup( pNtkCone );
Abc_NtkToAig( pNtkLogic );
// get the miter
pNtkMiter = Abc_NtkCreateTarget( pNtkLogic, pNtkLogic->vCos, vValues );
if ( fVerbose )
printf( "The miter for initial state computation has %d AIG nodes. ", Abc_NtkNodeNum(pNtkMiter) );
// solve the miter
clk = Abc_Clock();
RetValue = Abc_NtkMiterSat( pNtkMiter, (ABC_INT64_T)500000, (ABC_INT64_T)50000000, 0, NULL, NULL );
if ( fVerbose )
{ ABC_PRT( "SAT solving time", Abc_Clock() - clk ); }
// analyze the result
if ( RetValue == 1 )
printf( "Abc_NtkRetimeInitialValues(): The problem is unsatisfiable. DC latch values are used.\n" );
else if ( RetValue == -1 )
printf( "Abc_NtkRetimeInitialValues(): The SAT problem timed out. DC latch values are used.\n" );
else if ( !Abc_NtkRetimeVerifyModel( pNtkCone, vValues, pNtkMiter->pModel ) )
printf( "Abc_NtkRetimeInitialValues(): The computed counter-example is incorrect.\n" );
// set the values of the latches
vSolution = RetValue? NULL : Vec_IntAllocArray( pNtkMiter->pModel, Abc_NtkPiNum(pNtkLogic) );
pNtkMiter->pModel = NULL;
Abc_NtkDelete( pNtkMiter );
Abc_NtkDelete( pNtkLogic );
return vSolution;
}
/**Function*************************************************************
Synopsis [Verifies combinational equivalence by brute-force SAT.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkCecSat( Abc_Ntk_t * pNtk1, Abc_Ntk_t * pNtk2, int nConfLimit, int nInsLimit )
{
extern Abc_Ntk_t * Abc_NtkMulti( Abc_Ntk_t * pNtk, int nThresh, int nFaninMax, int fCnf, int fMulti, int fSimple, int fFactor );
Abc_Ntk_t * pMiter;
Abc_Ntk_t * pCnf;
int RetValue;
// get the miter of the two networks
pMiter = Abc_NtkMiter( pNtk1, pNtk2, 1, 0 );
if ( pMiter == NULL )
{
printf( "Miter computation has failed.\n" );
return;
}
RetValue = Abc_NtkMiterIsConstant( pMiter );
if ( RetValue == 0 )
{
printf( "Networks are NOT EQUIVALENT after structural hashing.\n" );
// report the error
pMiter->pModel = Abc_NtkVerifyGetCleanModel( pMiter, 1 );
Abc_NtkVerifyReportError( pNtk1, pNtk2, pMiter->pModel );
FREE( pMiter->pModel );
Abc_NtkDelete( pMiter );
return;
}
if ( RetValue == 1 )
{
Abc_NtkDelete( pMiter );
printf( "Networks are equivalent after structural hashing.\n" );
return;
}
// convert the miter into a CNF
pCnf = Abc_NtkMulti( pMiter, 0, 100, 1, 0, 0, 0 );
Abc_NtkDelete( pMiter );
if ( pCnf == NULL )
{
printf( "Renoding for CNF has failed.\n" );
return;
}
// solve the CNF using the SAT solver
RetValue = Abc_NtkMiterSat( pCnf, (sint64)nConfLimit, (sint64)nInsLimit, 0, NULL, NULL );
if ( RetValue == -1 )
printf( "Networks are undecided (SAT solver timed out).\n" );
else if ( RetValue == 0 )
printf( "Networks are NOT EQUIVALENT after SAT.\n" );
else
printf( "Networks are equivalent after SAT.\n" );
if ( pCnf->pModel )
Abc_NtkVerifyReportError( pNtk1, pNtk2, pCnf->pModel );
FREE( pCnf->pModel );
Abc_NtkDelete( pCnf );
}
/**Function*************************************************************
Synopsis [Solves the targets added by ABC_AddTarget().]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
enum CSAT_StatusT ABC_Solve( ABC_Manager mng )
{
Prove_Params_t * pParams = &mng->Params;
int RetValue, i;
// check if the target network is available
if ( mng->pTarget == NULL )
{ printf( "ABC_Solve: Target network is not derived by ABC_SolveInit().\n" ); return UNDETERMINED; }
// try to prove the miter using a number of techniques
if ( mng->mode )
RetValue = Abc_NtkMiterSat( mng->pTarget, (ABC_INT64_T)pParams->nMiteringLimitLast, (ABC_INT64_T)0, 0, NULL, NULL );
else
// RetValue = Abc_NtkMiterProve( &mng->pTarget, pParams ); // old CEC engine
RetValue = Abc_NtkIvyProve( &mng->pTarget, pParams ); // new CEC engine
// analyze the result
mng->pResult = ABC_TargetResAlloc( Abc_NtkCiNum(mng->pTarget) );
if ( RetValue == -1 )
mng->pResult->status = UNDETERMINED;
else if ( RetValue == 1 )
mng->pResult->status = UNSATISFIABLE;
else if ( RetValue == 0 )
{
mng->pResult->status = SATISFIABLE;
// create the array of PI names and values
for ( i = 0; i < mng->pResult->no_sig; i++ )
{
mng->pResult->names[i] = Extra_UtilStrsav( ABC_GetNodeName(mng, Abc_NtkCi(mng->pNtk, i)) );
mng->pResult->values[i] = mng->pTarget->pModel[i];
}
ABC_FREE( mng->pTarget->pModel );
}
else assert( 0 );
// delete the target
Abc_NtkDelete( mng->pTarget );
mng->pTarget = NULL;
// return the status
return mng->pResult->status;
}
/**Function*************************************************************
Synopsis [Attempts to solve the miter using a number of tricks.]
Description [Returns -1 if timed out; 0 if SAT; 1 if UNSAT. Returns
a simplified version of the original network (or a constant 0 network).
In case the network is not a constant zero and a SAT assignment is found,
pNtk->pModel contains a satisfying assignment.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkMiterProve( Abc_Ntk_t ** ppNtk, void * pPars )
{
Prove_Params_t * pParams = pPars;
Abc_Ntk_t * pNtk, * pNtkTemp;
int RetValue, nIter, nSatFails, Counter, clk, timeStart = clock();
sint64 nSatConfs, nSatInspects, nInspectLimit;
// get the starting network
pNtk = *ppNtk;
assert( Abc_NtkIsStrash(pNtk) );
assert( Abc_NtkPoNum(pNtk) == 1 );
if ( pParams->fVerbose )
{
printf( "RESOURCE LIMITS: Iterations = %d. Rewriting = %s. Fraiging = %s.\n",
pParams->nItersMax, pParams->fUseRewriting? "yes":"no", pParams->fUseFraiging? "yes":"no" );
printf( "Mitering = %d (%3.1f). Rewriting = %d (%3.1f). Fraiging = %d (%3.1f).\n",
pParams->nMiteringLimitStart, pParams->nMiteringLimitMulti,
pParams->nRewritingLimitStart, pParams->nRewritingLimitMulti,
pParams->nFraigingLimitStart, pParams->nFraigingLimitMulti );
printf( "Mitering last = %d.\n",
pParams->nMiteringLimitLast );
}
// if SAT only, solve without iteration
if ( !pParams->fUseRewriting && !pParams->fUseFraiging )
{
clk = clock();
RetValue = Abc_NtkMiterSat( pNtk, (sint64)pParams->nMiteringLimitLast, (sint64)0, 0, NULL, NULL );
Abc_NtkMiterPrint( pNtk, "SAT solving", clk, pParams->fVerbose );
*ppNtk = pNtk;
return RetValue;
}
// check the current resource limits
for ( nIter = 0; nIter < pParams->nItersMax; nIter++ )
{
if ( pParams->fVerbose )
{
printf( "ITERATION %2d : Confs = %6d. FraigBTL = %3d. \n", nIter+1,
(int)(pParams->nMiteringLimitStart * pow(pParams->nMiteringLimitMulti,nIter)),
(int)(pParams->nFraigingLimitStart * pow(pParams->nFraigingLimitMulti,nIter)) );
fflush( stdout );
}
// try brute-force SAT
clk = clock();
nInspectLimit = pParams->nTotalInspectLimit? pParams->nTotalInspectLimit - pParams->nTotalInspectsMade : 0;
RetValue = Abc_NtkMiterSat( pNtk, (sint64)(pParams->nMiteringLimitStart * pow(pParams->nMiteringLimitMulti,nIter)), (sint64)nInspectLimit, 0, &nSatConfs, &nSatInspects );
Abc_NtkMiterPrint( pNtk, "SAT solving", clk, pParams->fVerbose );
if ( RetValue >= 0 )
break;
// add to the number of backtracks and inspects
pParams->nTotalBacktracksMade += nSatConfs;
pParams->nTotalInspectsMade += nSatInspects;
// check if global resource limit is reached
if ( (pParams->nTotalBacktrackLimit && pParams->nTotalBacktracksMade >= pParams->nTotalBacktrackLimit) ||
(pParams->nTotalInspectLimit && pParams->nTotalInspectsMade >= pParams->nTotalInspectLimit) )
{
printf( "Reached global limit on conflicts/inspects. Quitting.\n" );
*ppNtk = pNtk;
return -1;
}
// try rewriting
if ( pParams->fUseRewriting )
{
clk = clock();
Counter = (int)(pParams->nRewritingLimitStart * pow(pParams->nRewritingLimitMulti,nIter));
// Counter = 1;
while ( 1 )
{
/*
extern Abc_Ntk_t * Abc_NtkIvyResyn( Abc_Ntk_t * pNtk, int fUpdateLevel, int fVerbose );
pNtk = Abc_NtkIvyResyn( pNtkTemp = pNtk, 0, 0 ); Abc_NtkDelete( pNtkTemp );
if ( (RetValue = Abc_NtkMiterIsConstant(pNtk)) >= 0 )
break;
if ( --Counter == 0 )
break;
*/
/*
Abc_NtkRewrite( pNtk, 0, 0, 0, 0, 0 );
if ( (RetValue = Abc_NtkMiterIsConstant(pNtk)) >= 0 )
break;
if ( --Counter == 0 )
break;
*/
Abc_NtkRewrite( pNtk, 0, 0, 0, 0, 0 );
if ( (RetValue = Abc_NtkMiterIsConstant(pNtk)) >= 0 )
break;
if ( --Counter == 0 )
break;
Abc_NtkRefactor( pNtk, 10, 16, 0, 0, 0, 0 );
if ( (RetValue = Abc_NtkMiterIsConstant(pNtk)) >= 0 )
break;
if ( --Counter == 0 )
break;
pNtk = Abc_NtkBalance( pNtkTemp = pNtk, 0, 0, 0 ); Abc_NtkDelete( pNtkTemp );
if ( (RetValue = Abc_NtkMiterIsConstant(pNtk)) >= 0 )
break;
if ( --Counter == 0 )
break;
}
Abc_NtkMiterPrint( pNtk, "Rewriting ", clk, pParams->fVerbose );
}
if ( pParams->fUseFraiging )
{
// try FRAIGing
clk = clock();
nInspectLimit = pParams->nTotalInspectLimit? pParams->nTotalInspectLimit - pParams->nTotalInspectsMade : 0;
pNtk = Abc_NtkMiterFraig( pNtkTemp = pNtk, (int)(pParams->nFraigingLimitStart * pow(pParams->nFraigingLimitMulti,nIter)), nInspectLimit, &RetValue, &nSatFails, &nSatConfs, &nSatInspects ); Abc_NtkDelete( pNtkTemp );
Abc_NtkMiterPrint( pNtk, "FRAIGing ", clk, pParams->fVerbose );
// printf( "NumFails = %d\n", nSatFails );
if ( RetValue >= 0 )
break;
// add to the number of backtracks and inspects
pParams->nTotalBacktracksMade += nSatConfs;
pParams->nTotalInspectsMade += nSatInspects;
// check if global resource limit is reached
if ( (pParams->nTotalBacktrackLimit && pParams->nTotalBacktracksMade >= pParams->nTotalBacktrackLimit) ||
(pParams->nTotalInspectLimit && pParams->nTotalInspectsMade >= pParams->nTotalInspectLimit) )
{
printf( "Reached global limit on conflicts/inspects. Quitting.\n" );
*ppNtk = pNtk;
return -1;
}
}
}
// try to prove it using brute force SAT
if ( RetValue < 0 && pParams->fUseBdds )
{
if ( pParams->fVerbose )
{
printf( "Attempting BDDs with node limit %d ...\n", pParams->nBddSizeLimit );
fflush( stdout );
}
clk = clock();
pNtk = Abc_NtkCollapse( pNtkTemp = pNtk, pParams->nBddSizeLimit, 0, pParams->fBddReorder, 0 );
if ( pNtk )
{
Abc_NtkDelete( pNtkTemp );
RetValue = ( (Abc_NtkNodeNum(pNtk) == 1) && (Abc_ObjFanin0(Abc_NtkPo(pNtk,0))->pData == Cudd_ReadLogicZero(pNtk->pManFunc)) );
}
else
pNtk = pNtkTemp;
Abc_NtkMiterPrint( pNtk, "BDD building", clk, pParams->fVerbose );
}
if ( RetValue < 0 )
{
if ( pParams->fVerbose )
{
printf( "Attempting SAT with conflict limit %d ...\n", pParams->nMiteringLimitLast );
fflush( stdout );
}
clk = clock();
nInspectLimit = pParams->nTotalInspectLimit? pParams->nTotalInspectLimit - pParams->nTotalInspectsMade : 0;
RetValue = Abc_NtkMiterSat( pNtk, (sint64)pParams->nMiteringLimitLast, (sint64)nInspectLimit, 0, NULL, NULL );
Abc_NtkMiterPrint( pNtk, "SAT solving", clk, pParams->fVerbose );
}
// assign the model if it was proved by rewriting (const 1 miter)
if ( RetValue == 0 && pNtk->pModel == NULL )
{
pNtk->pModel = ALLOC( int, Abc_NtkCiNum(pNtk) );
memset( pNtk->pModel, 0, sizeof(int) * Abc_NtkCiNum(pNtk) );
}
/**Function*************************************************************
Synopsis [Solve the QBF problem EpAx[M(p,x)].]
Description [The network should be a Boolean network where, the variables
p go first, followed by variables x.
The number of parameters is nPars.
The number of iterations to try is nItersMax.
The inputs to try are in vPiValues, and it will store the
results if a model is found.
The return value is 1 if the problem is false, 0 if the problem is
true (and an assignment to p returned via vPiValeus), -1 if the
iteration limit reached, and -2 if the sat solver times out. ]
SideEffects []
SeeAlso []
***********************************************************************/
int AbcBridge_NtkQbf( Abc_Ntk_t * pNtk,
int nPars,
int nItersMax,
Vec_Int_t* vPiValues)
{
Abc_Ntk_t * pNtkVer, * pNtkSyn, * pNtkSyn2, * pNtkTemp;
int nIters, nInputs, RetValue, fFound = 0;
assert( Abc_NtkIsStrash(pNtk) );
assert( Abc_NtkIsComb(pNtk) );
assert( Abc_NtkPoNum(pNtk) == 1 );
assert( nPars > 0 && nPars < Abc_NtkPiNum(pNtk) );
// assert( Abc_NtkPiNum(pNtk)-nPars < 32 );
nInputs = Abc_NtkPiNum(pNtk) - nPars;
assert(Vec_IntSize(vPiValues) == Abc_NtkPiNum(pNtk));
AbcBridge_NtkVectorClearPars( vPiValues, nPars );
pNtkSyn = Abc_NtkMiterCofactor( pNtk, vPiValues );
// iteratively solve
for ( nIters = 0; nIters < nItersMax; nIters++ )
{
// solve the synthesis instance
// RetValue = Abc_NtkMiterSat( pNtkSyn, 0, 0, 0, NULL, NULL );
RetValue = Abc_NtkDSat( pNtkSyn, (ABC_INT64_T)0, (ABC_INT64_T)0, 0, 0, 0, 1, 0, 0, 0 );
if ( RetValue == 0 )
AbcBridge_NtkModelToVector( pNtkSyn, vPiValues );
// Formula is unsat when forall variables replaced with concrete inputs, and
// thus unsat in general.
if ( RetValue == 1 )
{
Abc_NtkDelete(pNtkSyn);
return 1; // Return UNSAT
}
// Synthesis timed out.
if (RetValue == -1) {
Abc_NtkDelete(pNtkSyn);
return -2;
}
// there is a counter-example
// construct the verification instance
AbcBridge_NtkVectorClearVars( pNtk, vPiValues, nPars );
pNtkVer = Abc_NtkMiterCofactor( pNtk, vPiValues );
// complement the output
Abc_ObjXorFaninC( Abc_NtkPo(pNtkVer,0), 0 );
// solve the verification instance
RetValue = Abc_NtkMiterSat( pNtkVer, 0, 0, 0, NULL, NULL );
if ( RetValue == 0 )
AbcBridge_NtkModelToVector( pNtkVer, vPiValues );
Abc_NtkDelete( pNtkVer );
if ( RetValue == 1 )
{
Abc_NtkDelete( pNtkSyn );
return 0; // Return sat
}
// If verification timed out.
if ( RetValue == -1 ) {
Abc_NtkDelete(pNtkSyn);
return -2;
}
// there is a counter-example
// create a new synthesis network
AbcBridge_NtkVectorClearPars( vPiValues, nPars );
pNtkSyn2 = Abc_NtkMiterCofactor( pNtk, vPiValues );
// add to the synthesis instance
pNtkSyn = Abc_NtkMiterAnd( pNtkTemp = pNtkSyn, pNtkSyn2, 0, 0 );
Abc_NtkDelete( pNtkSyn2 );
Abc_NtkDelete( pNtkTemp );
}
Abc_NtkDelete( pNtkSyn );
// Limit reached.
return -1;
}
/**Function*************************************************************
Synopsis [Implements the given retiming on the sequential AIG.]
Description [Returns 0 of initial state computation fails.]
SideEffects []
SeeAlso []
***********************************************************************/
int Seq_NtkImplementRetimingBackward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves, int fVerbose )
{
Seq_RetEdge_t RetEdge;
stmm_table * tTable;
stmm_generator * gen;
Vec_Int_t * vValues;
Abc_Ntk_t * pNtkProb, * pNtkMiter, * pNtkCnf;
Abc_Obj_t * pNode, * pNodeNew;
int * pModel, RetValue, i, clk;
// return if the retiming is trivial
if ( Vec_PtrSize(vMoves) == 0 )
return 1;
// create the network for the initial state computation
// start the table and the array of PO values
pNtkProb = Abc_NtkAlloc( ABC_NTK_LOGIC, ABC_FUNC_SOP, 1 );
tTable = stmm_init_table( stmm_numcmp, stmm_numhash );
vValues = Vec_IntAlloc( 100 );
// perform the backward moves and build the network for initial state computation
RetValue = 0;
Vec_PtrForEachEntry( vMoves, pNode, i )
RetValue |= Abc_ObjRetimeBackward( pNode, pNtkProb, tTable, vValues );
// add the PIs corresponding to the white spots
stmm_foreach_item( tTable, gen, (char **)&RetEdge, (char **)&pNodeNew )
Abc_ObjAddFanin( pNodeNew, Abc_NtkCreatePi(pNtkProb) );
// add the PI/PO names
Abc_NtkAddDummyPiNames( pNtkProb );
Abc_NtkAddDummyPoNames( pNtkProb );
Abc_NtkAddDummyAssertNames( pNtkProb );
// make sure everything is okay with the network structure
if ( !Abc_NtkDoCheck( pNtkProb ) )
{
printf( "Seq_NtkImplementRetimingBackward: The internal network check has failed.\n" );
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
Abc_NtkDelete( pNtkProb );
stmm_free_table( tTable );
Vec_IntFree( vValues );
return 0;
}
// check if conflict is found
if ( RetValue )
{
printf( "Seq_NtkImplementRetimingBackward: A top level conflict is detected. DC latch values are used.\n" );
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
Abc_NtkDelete( pNtkProb );
stmm_free_table( tTable );
Vec_IntFree( vValues );
return 0;
}
// get the miter cone
pNtkMiter = Abc_NtkCreateTarget( pNtkProb, pNtkProb->vCos, vValues );
Abc_NtkDelete( pNtkProb );
Vec_IntFree( vValues );
if ( fVerbose )
printf( "The number of ANDs in the AIG = %5d.\n", Abc_NtkNodeNum(pNtkMiter) );
// transform the miter into a logic network for efficient CNF construction
// pNtkCnf = Abc_Ntk_Renode( pNtkMiter, 0, 100, 1, 0, 0 );
// Abc_NtkDelete( pNtkMiter );
pNtkCnf = pNtkMiter;
// solve the miter
clk = clock();
// RetValue = Abc_NtkMiterSat_OldAndRusty( pNtkCnf, 30, 0 );
RetValue = Abc_NtkMiterSat( pNtkCnf, (sint64)500000, (sint64)50000000, 0, 0, NULL, NULL );
if ( fVerbose )
if ( clock() - clk > 100 )
{
PRT( "SAT solving time", clock() - clk );
}
pModel = pNtkCnf->pModel; pNtkCnf->pModel = NULL;
Abc_NtkDelete( pNtkCnf );
// analyze the result
if ( RetValue == -1 || RetValue == 1 )
{
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
if ( RetValue == 1 )
printf( "Seq_NtkImplementRetimingBackward: The problem is unsatisfiable. DC latch values are used.\n" );
else
printf( "Seq_NtkImplementRetimingBackward: The SAT problem timed out. DC latch values are used.\n" );
stmm_free_table( tTable );
return 0;
}
// set the values of the latches
Abc_NtkRetimeSetInitialValues( pNtk, tTable, pModel );
stmm_free_table( tTable );
free( pModel );
return 1;
}