/**Function*************************************************************
Synopsis [Performs induction by unrolling timeframes backward.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Saig_ManInduction( Aig_Man_t * p, int nFramesMax, int nConfMax, int fUnique, int fUniqueAll, int fGetCex, int fVerbose, int fVeryVerbose )
{
sat_solver * pSat;
Aig_Man_t * pAigPart;
Cnf_Dat_t * pCnfPart;
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;
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 );
// 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] );
}
}
/**Function*************************************************************
Synopsis [Interplates while the number of conflicts is not exceeded.]
Description [Returns 1 if proven. 0 if failed. -1 if undecided.]
SideEffects [Does not check the property in 0-th frame.]
SeeAlso []
***********************************************************************/
int Inter_ManPerformInterpolation( Aig_Man_t * pAig, Inter_ManParams_t * pPars, int * piFrame )
{
extern int Inter_ManCheckInductiveContainment( Aig_Man_t * pTrans, Aig_Man_t * pInter, int nSteps, int fBackward );
Inter_Man_t * p;
Inter_Check_t * pCheck = NULL;
Aig_Man_t * pAigTemp;
int s, i, RetValue, Status;
abctime clk, clk2, clkTotal = Abc_Clock(), timeTemp = 0;
abctime nTimeNewOut = pPars->nSecLimit ? pPars->nSecLimit * CLOCKS_PER_SEC + Abc_Clock() : 0;
// enable ORing of the interpolants, if containment check is performed inductively with K > 1
if ( pPars->nFramesK > 1 )
pPars->fTransLoop = 1;
// sanity checks
assert( Saig_ManRegNum(pAig) > 0 );
assert( Saig_ManPiNum(pAig) > 0 );
assert( Saig_ManPoNum(pAig)-Saig_ManConstrNum(pAig) == 1 );
if ( pPars->fVerbose && Saig_ManConstrNum(pAig) )
printf( "Performing interpolation with %d constraints...\n", Saig_ManConstrNum(pAig) );
if ( Inter_ManCheckInitialState(pAig) )
{
*piFrame = -1;
printf( "Property trivially fails in the initial state.\n" );
return 0;
}
/*
if ( Inter_ManCheckAllStates(pAig) )
{
printf( "Property trivially holds in all states.\n" );
return 1;
}
*/
// create interpolation manager
// can perform SAT sweeping and/or rewriting of this AIG...
p = Inter_ManCreate( pAig, pPars );
if ( pPars->fTransLoop )
p->pAigTrans = Inter_ManStartOneOutput( pAig, 0 );
else
p->pAigTrans = Inter_ManStartDuplicated( pAig );
// derive CNF for the transformed AIG
clk = Abc_Clock();
p->pCnfAig = Cnf_Derive( p->pAigTrans, Aig_ManRegNum(p->pAigTrans) );
p->timeCnf += Abc_Clock() - clk;
if ( pPars->fVerbose )
{
printf( "AIG: PI/PO/Reg = %d/%d/%d. And = %d. Lev = %d. CNF: Var/Cla = %d/%d.\n",
Saig_ManPiNum(pAig), Saig_ManPoNum(pAig), Saig_ManRegNum(pAig),
Aig_ManAndNum(pAig), Aig_ManLevelNum(pAig),
p->pCnfAig->nVars, p->pCnfAig->nClauses );
}
// derive interpolant
*piFrame = -1;
p->nFrames = 1;
for ( s = 0; ; s++ )
{
Cnf_Dat_t * pCnfInter2;
clk2 = Abc_Clock();
// initial state
if ( pPars->fUseBackward )
p->pInter = Inter_ManStartOneOutput( pAig, 1 );
else
p->pInter = Inter_ManStartInitState( Aig_ManRegNum(pAig) );
assert( Aig_ManCoNum(p->pInter) == 1 );
clk = Abc_Clock();
p->pCnfInter = Cnf_Derive( p->pInter, 0 );
p->timeCnf += Abc_Clock() - clk;
// timeframes
p->pFrames = Inter_ManFramesInter( pAig, p->nFrames, pPars->fUseBackward, pPars->fUseTwoFrames );
clk = Abc_Clock();
if ( pPars->fRewrite )
{
p->pFrames = Dar_ManRwsat( pAigTemp = p->pFrames, 1, 0 );
Aig_ManStop( pAigTemp );
// p->pFrames = Fra_FraigEquivence( pAigTemp = p->pFrames, 100, 0 );
// Aig_ManStop( pAigTemp );
}
p->timeRwr += Abc_Clock() - clk;
// can also do SAT sweeping on the timeframes...
clk = Abc_Clock();
if ( pPars->fUseBackward )
p->pCnfFrames = Cnf_Derive( p->pFrames, Aig_ManCoNum(p->pFrames) );
else
// p->pCnfFrames = Cnf_Derive( p->pFrames, 0 );
p->pCnfFrames = Cnf_DeriveSimple( p->pFrames, 0 );
p->timeCnf += Abc_Clock() - clk;
// report statistics
if ( pPars->fVerbose )
{
printf( "Step = %2d. Frames = 1 + %d. And = %5d. Lev = %5d. ",
s+1, p->nFrames, Aig_ManNodeNum(p->pFrames), Aig_ManLevelNum(p->pFrames) );
ABC_PRT( "Time", Abc_Clock() - clk2 );
}
//////////////////////////////////////////
// start containment checking
if ( !(pPars->fTransLoop || pPars->fUseBackward || pPars->nFramesK > 1) )
{
pCheck = Inter_CheckStart( p->pAigTrans, pPars->nFramesK );
// try new containment check for the initial state
clk = Abc_Clock();
pCnfInter2 = Cnf_Derive( p->pInter, 1 );
p->timeCnf += Abc_Clock() - clk;
clk = Abc_Clock();
RetValue = Inter_CheckPerform( pCheck, pCnfInter2, nTimeNewOut );
p->timeEqu += Abc_Clock() - clk;
// assert( RetValue == 0 );
Cnf_DataFree( pCnfInter2 );
if ( p->vInters )
Vec_PtrPush( p->vInters, Aig_ManDupSimple(p->pInter) );
}
//////////////////////////////////////////
// iterate the interpolation procedure
for ( i = 0; ; i++ )
{
if ( pPars->nFramesMax && p->nFrames + i >= pPars->nFramesMax )
{
if ( pPars->fVerbose )
printf( "Reached limit (%d) on the number of timeframes.\n", pPars->nFramesMax );
p->timeTotal = Abc_Clock() - clkTotal;
Inter_ManStop( p, 0 );
Inter_CheckStop( pCheck );
return -1;
}
// perform interpolation
clk = Abc_Clock();
#ifdef ABC_USE_LIBRARIES
if ( pPars->fUseMiniSat )
{
assert( !pPars->fUseBackward );
RetValue = Inter_ManPerformOneStepM114p( p, pPars->fUsePudlak, pPars->fUseOther );
}
else
#endif
RetValue = Inter_ManPerformOneStep( p, pPars->fUseBias, pPars->fUseBackward, nTimeNewOut );
if ( pPars->fVerbose )
{
printf( " I = %2d. Bmc =%3d. IntAnd =%6d. IntLev =%5d. Conf =%6d. ",
i+1, i + 1 + p->nFrames, Aig_ManNodeNum(p->pInter), Aig_ManLevelNum(p->pInter), p->nConfCur );
ABC_PRT( "Time", Abc_Clock() - clk );
}
// remember the number of timeframes completed
pPars->iFrameMax = i - 1 + p->nFrames;
if ( RetValue == 0 ) // found a (spurious?) counter-example
{
if ( i == 0 ) // real counterexample
{
if ( pPars->fVerbose )
printf( "Found a real counterexample in frame %d.\n", p->nFrames );
p->timeTotal = Abc_Clock() - clkTotal;
*piFrame = p->nFrames;
// pAig->pSeqModel = (Abc_Cex_t *)Inter_ManGetCounterExample( pAig, p->nFrames+1, pPars->fVerbose );
{
int RetValue;
Saig_ParBmc_t ParsBmc, * pParsBmc = &ParsBmc;
Saig_ParBmcSetDefaultParams( pParsBmc );
pParsBmc->nConfLimit = 100000000;
pParsBmc->nStart = p->nFrames;
pParsBmc->fVerbose = pPars->fVerbose;
RetValue = Saig_ManBmcScalable( pAig, pParsBmc );
if ( RetValue == 1 )
printf( "Error: The problem should be SAT but it is UNSAT.\n" );
else if ( RetValue == -1 )
printf( "Error: The problem timed out.\n" );
}
Inter_ManStop( p, 0 );
Inter_CheckStop( pCheck );
return 0;
}
// likely spurious counter-example
p->nFrames += i;
Inter_ManClean( p );
break;
}
else if ( RetValue == -1 )
{
if ( pPars->nSecLimit && Abc_Clock() > nTimeNewOut ) // timed out
{
if ( pPars->fVerbose )
printf( "Reached timeout (%d seconds).\n", pPars->nSecLimit );
}
else
{
assert( p->nConfCur >= p->nConfLimit );
if ( pPars->fVerbose )
printf( "Reached limit (%d) on the number of conflicts.\n", p->nConfLimit );
}
p->timeTotal = Abc_Clock() - clkTotal;
Inter_ManStop( p, 0 );
Inter_CheckStop( pCheck );
return -1;
}
assert( RetValue == 1 ); // found new interpolant
// compress the interpolant
clk = Abc_Clock();
if ( p->pInterNew )
{
// Ioa_WriteAiger( p->pInterNew, "interpol.aig", 0, 0 );
p->pInterNew = Dar_ManRwsat( pAigTemp = p->pInterNew, 1, 0 );
// p->pInterNew = Dar_ManRwsat( pAigTemp = p->pInterNew, 0, 0 );
Aig_ManStop( pAigTemp );
}
p->timeRwr += Abc_Clock() - clk;
// check if interpolant is trivial
if ( p->pInterNew == NULL || Aig_ObjChild0(Aig_ManCo(p->pInterNew,0)) == Aig_ManConst0(p->pInterNew) )
{
// printf( "interpolant is constant 0\n" );
if ( pPars->fVerbose )
printf( "The problem is trivially true for all states.\n" );
p->timeTotal = Abc_Clock() - clkTotal;
Inter_ManStop( p, 1 );
Inter_CheckStop( pCheck );
return 1;
}
// check containment of interpolants
clk = Abc_Clock();
if ( pPars->fCheckKstep ) // k-step unique-state induction
{
if ( Aig_ManCiNum(p->pInterNew) == Aig_ManCiNum(p->pInter) )
{
if ( pPars->fTransLoop || pPars->fUseBackward || pPars->nFramesK > 1 )
{
clk2 = Abc_Clock();
Status = Inter_ManCheckInductiveContainment( p->pAigTrans, p->pInterNew, Abc_MinInt(i + 1, pPars->nFramesK), pPars->fUseBackward );
timeTemp = Abc_Clock() - clk2;
}
else
{ // new containment check
clk2 = Abc_Clock();
pCnfInter2 = Cnf_Derive( p->pInterNew, 1 );
p->timeCnf += Abc_Clock() - clk2;
timeTemp = Abc_Clock() - clk2;
Status = Inter_CheckPerform( pCheck, pCnfInter2, nTimeNewOut );
Cnf_DataFree( pCnfInter2 );
if ( p->vInters )
Vec_PtrPush( p->vInters, Aig_ManDupSimple(p->pInterNew) );
}
}
else
Status = 0;
}
else // combinational containment
{
if ( Aig_ManCiNum(p->pInterNew) == Aig_ManCiNum(p->pInter) )
Status = Inter_ManCheckContainment( p->pInterNew, p->pInter );
else
Status = 0;
}
p->timeEqu += Abc_Clock() - clk - timeTemp;
if ( Status ) // contained
{
if ( pPars->fVerbose )
printf( "Proved containment of interpolants.\n" );
p->timeTotal = Abc_Clock() - clkTotal;
Inter_ManStop( p, 1 );
Inter_CheckStop( pCheck );
return 1;
}
if ( pPars->nSecLimit && Abc_Clock() > nTimeNewOut )
{
printf( "Reached timeout (%d seconds).\n", pPars->nSecLimit );
p->timeTotal = Abc_Clock() - clkTotal;
Inter_ManStop( p, 1 );
Inter_CheckStop( pCheck );
return -1;
}
// save interpolant and convert it into CNF
if ( pPars->fTransLoop )
{
Aig_ManStop( p->pInter );
p->pInter = p->pInterNew;
}
else
{
if ( pPars->fUseBackward )
{
p->pInter = Aig_ManCreateMiter( pAigTemp = p->pInter, p->pInterNew, 2 );
Aig_ManStop( pAigTemp );
Aig_ManStop( p->pInterNew );
// compress the interpolant
clk = Abc_Clock();
p->pInter = Dar_ManRwsat( pAigTemp = p->pInter, 1, 0 );
Aig_ManStop( pAigTemp );
p->timeRwr += Abc_Clock() - clk;
}
else // forward with the new containment checking (using only the frontier)
{
Aig_ManStop( p->pInter );
p->pInter = p->pInterNew;
}
}
p->pInterNew = NULL;
Cnf_DataFree( p->pCnfInter );
clk = Abc_Clock();
p->pCnfInter = Cnf_Derive( p->pInter, 0 );
p->timeCnf += Abc_Clock() - clk;
}
// start containment checking
Inter_CheckStop( pCheck );
}
assert( 0 );
return RetValue;
}
void ToCNFAIG::toCNF(const BBNodeAIG& top, Cnf_Dat_t*& cnfData,
ToSATBase::ASTNodeToSATVar& nodeToVar,
bool needAbsRef, BBNodeManagerAIG& mgr) {
assert(cnfData == NULL);
Aig_ObjCreatePo(mgr.aigMgr, top.n);
if (!needAbsRef) {
Aig_ManCleanup( mgr.aigMgr); // remove nodes not connected to the PO.
}
Aig_ManCheck( mgr.aigMgr); // check that AIG looks ok.
assert(Aig_ManPoNum(mgr.aigMgr) == 1);
// UseZeroes gives assertion errors.
// Rewriting is sometimes very slow. Can it be configured to be faster?
// What about refactoring???
int nodeCount = mgr.aigMgr->nObjs[AIG_OBJ_AND];
if (uf.stats_flag)
cerr << "Nodes before AIG rewrite:" << nodeCount << endl;
if (!needAbsRef && uf.isSet("aig-rewrite","0")) {
Dar_LibStart();
Aig_Man_t * pTemp;
Dar_RwrPar_t Pars, *pPars = &Pars;
Dar_ManDefaultRwrParams(pPars);
// Assertion errors occur with this enabled.
// pPars->fUseZeros = 1;
// For mul63bit.smt2 with iterations =3 & nCutsMax = 8
// CNF generation was taking 139 seconds, solving 10 seconds.
// With nCutsMax =2, CNF generation takes 16 seconds, solving 10 seconds.
// The rewriting doesn't remove as many nodes of course..
int iterations = 3;
for (int i = 0; i < iterations; i++) {
mgr.aigMgr = Aig_ManDup(pTemp = mgr.aigMgr, 0);
Aig_ManStop(pTemp);
Dar_ManRewrite(mgr.aigMgr, pPars);
mgr.aigMgr = Aig_ManDup(pTemp = mgr.aigMgr, 0);
Aig_ManStop(pTemp);
if (uf.stats_flag)
cerr << "After rewrite [" << i << "] nodes:"
<< mgr.aigMgr->nObjs[AIG_OBJ_AND] << endl;
if (nodeCount == mgr.aigMgr->nObjs[AIG_OBJ_AND])
break;
}
}
if (!uf.isSet("simple-cnf","0")) {
cnfData = Cnf_Derive(mgr.aigMgr, 0);
if (uf.stats_flag)
cerr << "advanced CNF" << endl;
} else {
cnfData = Cnf_DeriveSimple(mgr.aigMgr, 0);
if (uf.stats_flag)
cerr << "simple CNF" << endl;
}
BBNodeManagerAIG::SymbolToBBNode::const_iterator it;
assert(nodeToVar.size() == 0);
//todo. cf. with addvariables above...
// Each symbol maps to a vector of CNF variables.
for (it = mgr.symbolToBBNode.begin(); it != mgr.symbolToBBNode.end(); it++) {
const ASTNode& n = it->first;
const vector<BBNodeAIG> &b = it->second;
assert(nodeToVar.find(n) == nodeToVar.end());
const int width = (n.GetType() == BOOLEAN_TYPE) ? 1 : n.GetValueWidth();
// INT_MAX for parts of symbols that didn't get encoded.
vector<unsigned> v(width, ~((unsigned) 0));
for (unsigned i = 0; i < b.size(); i++) {
if (!b[i].IsNull()) {
Aig_Obj_t * pObj;
pObj = (Aig_Obj_t*) Vec_PtrEntry(mgr.aigMgr->vPis,
b[i].symbol_index);
v[i] = cnfData->pVarNums[pObj->Id];
}
}
nodeToVar.insert(make_pair(n, v));
}
assert(cnfData != NULL);
}
