Version abc80130_2

1 files changed, 462 insertions, 32 deletions

diff --git a/src/base/abci/abcCut.c b/src/base/abci/abcCut.c
index f487bd1b..d399ce5f 100644
--- a/src/base/abci/abcCut.c
+++ b/src/base/abci/abcCut.c
@@ -25,8 +25,16 @@
 ///                        DECLARATIONS                              ///
 ////////////////////////////////////////////////////////////////////////
 
+static void Abc_NtkPrintCuts( void * p, Abc_Ntk_t * pNtk, int fSeq );
+static void Abc_NtkPrintCuts_( void * p, Abc_Ntk_t * pNtk, int fSeq );
+
+extern int nTotal, nGood, nEqual;
+
+static Vec_Int_t * Abc_NtkGetNodeAttributes( Abc_Ntk_t * pNtk );
+static int Abc_NtkComputeArea( Abc_Ntk_t * pNtk, Cut_Man_t * p );
+
 ////////////////////////////////////////////////////////////////////////
-///                     FUNCTION DEFITIONS                           ///
+///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////
 
 /**Function*************************************************************
@@ -42,18 +50,30 @@
 ***********************************************************************/
 Cut_Man_t * Abc_NtkCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams )
 {
+    ProgressBar * pProgress;
     Cut_Man_t *  p;
-    Abc_Obj_t * pObj, * pDriver, * pNode;
+    Abc_Obj_t * pObj, * pNode;
     Vec_Ptr_t * vNodes;
     Vec_Int_t * vChoices;
     int i;
     int clk = clock();
 
-    assert( Abc_NtkIsStrash(pNtk) );
+    extern void Abc_NtkBalanceAttach( Abc_Ntk_t * pNtk );
+    extern void Abc_NtkBalanceDetach( Abc_Ntk_t * pNtk );
 
+    nTotal = nGood = nEqual = 0;
+
+    assert( Abc_NtkIsStrash(pNtk) );
     // start the manager
     pParams->nIdsMax = Abc_NtkObjNumMax( pNtk );
     p = Cut_ManStart( pParams );
+    // compute node attributes if local or global cuts are requested
+    if ( pParams->fGlobal || pParams->fLocal )
+    {
+        extern Vec_Int_t * Abc_NtkGetNodeAttributes( Abc_Ntk_t * pNtk );
+        Cut_ManSetNodeAttrs( p, Abc_NtkGetNodeAttributes(pNtk) );
+    }
+    // prepare for cut dropping
     if ( pParams->fDrop )
         Cut_ManSetFanoutCounts( p, Abc_NtkFanoutCounts(pNtk) );
     // set cuts for PIs
@@ -61,8 +81,9 @@ Cut_Man_t * Abc_NtkCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams )
         if ( Abc_ObjFanoutNum(pObj) > 0 )
             Cut_NodeSetTriv( p, pObj->Id );
     // compute cuts for internal nodes
-    vNodes = Abc_AigDfs( pNtk, 0, 1 );
+    vNodes = Abc_AigDfs( pNtk, 0, 1 ); // collects POs
     vChoices = Vec_IntAlloc( 100 );
+    pProgress = Extra_ProgressBarStart( stdout, Vec_PtrSize(vNodes) );
     Vec_PtrForEachEntry( vNodes, pObj, i )
     {
         // when we reached a CO, it is time to deallocate the cuts
@@ -73,12 +94,19 @@ Cut_Man_t * Abc_NtkCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams )
             continue;
         }
         // skip constant node, it has no cuts
-        if ( Abc_NodeIsConst(pObj) )
-            continue;
+//        if ( Abc_NodeIsConst(pObj) )
+//            continue;
+        Extra_ProgressBarUpdate( pProgress, i, NULL );
         // compute the cuts to the internal node
-        Abc_NodeGetCuts( p, pObj );  
+        Abc_NodeGetCuts( p, pObj, pParams->fDag, pParams->fTree );  
+        // consider dropping the fanins cuts
+        if ( pParams->fDrop )
+        {
+            Cut_NodeTryDroppingCuts( p, Abc_ObjFaninId0(pObj) );
+            Cut_NodeTryDroppingCuts( p, Abc_ObjFaninId1(pObj) );
+        }
         // add cuts due to choices
-        if ( Abc_NodeIsAigChoice(pObj) )
+        if ( Abc_AigNodeIsChoice(pObj) )
         {
             Vec_IntClear( vChoices );
             for ( pNode = pObj; pNode; pNode = pNode->pData )
@@ -86,31 +114,203 @@ Cut_Man_t * Abc_NtkCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams )
             Cut_NodeUnionCuts( p, vChoices );
         }
     }
-    if ( !pParams->fSeq )
+    Extra_ProgressBarStop( pProgress );
+    Vec_PtrFree( vNodes );
+    Vec_IntFree( vChoices );
+    Cut_ManPrintStats( p );
+PRT( "TOTAL ", clock() - clk );
+    printf( "Area = %d.\n", Abc_NtkComputeArea( pNtk, p ) );
+//Abc_NtkPrintCuts( p, pNtk, 0 );
+//    Cut_ManPrintStatsToFile( p, pNtk->pSpec, clock() - clk );
+
+    // temporary printout of stats
+    if ( nTotal )
+    printf( "Total cuts = %d. Good cuts = %d.  Ratio = %5.2f\n", nTotal, nGood, ((double)nGood)/nTotal );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Cut computation using the oracle.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_NtkCutsOracle( Abc_Ntk_t * pNtk, Cut_Oracle_t * p )
+{
+    Abc_Obj_t * pObj;
+    Vec_Ptr_t * vNodes;
+    int i, clk = clock();
+    int fDrop = Cut_OracleReadDrop(p);
+
+    assert( Abc_NtkIsStrash(pNtk) );
+
+    // prepare cut droppping
+    if ( fDrop )
+        Cut_OracleSetFanoutCounts( p, Abc_NtkFanoutCounts(pNtk) );
+
+    // set cuts for PIs
+    Abc_NtkForEachCi( pNtk, pObj, i )
+        if ( Abc_ObjFanoutNum(pObj) > 0 )
+            Cut_OracleNodeSetTriv( p, pObj->Id );
+
+    // compute cuts for internal nodes
+    vNodes = Abc_AigDfs( pNtk, 0, 1 ); // collects POs
+    Vec_PtrForEachEntry( vNodes, pObj, i )
     {
-        Vec_PtrFree( vNodes );
-        Vec_IntFree( vChoices );
-PRT( "Total", clock() - clk );
-        return p;
+        // when we reached a CO, it is time to deallocate the cuts
+        if ( Abc_ObjIsCo(pObj) )
+        {
+            if ( fDrop )
+                Cut_OracleTryDroppingCuts( p, Abc_ObjFaninId0(pObj) );
+            continue;
+        }
+        // skip constant node, it has no cuts
+//        if ( Abc_NodeIsConst(pObj) )
+//            continue;
+        // compute the cuts to the internal node
+        Cut_OracleComputeCuts( p, pObj->Id, Abc_ObjFaninId0(pObj), Abc_ObjFaninId1(pObj),  
+                Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj) );
+        // consider dropping the fanins cuts
+        if ( fDrop )
+        {
+            Cut_OracleTryDroppingCuts( p, Abc_ObjFaninId0(pObj) );
+            Cut_OracleTryDroppingCuts( p, Abc_ObjFaninId1(pObj) );
+        }
     }
-    assert( 0 );
+    Vec_PtrFree( vNodes );
+//PRT( "Total", clock() - clk );
+//Abc_NtkPrintCuts_( p, pNtk, 0 );
+}
+
 
-    // compute sequential cuts
-    Abc_NtkIncrementTravId( pNtk );
-    Abc_NtkForEachLatch( pNtk, pObj, i )
+/**Function*************************************************************
+
+  Synopsis    [Computes the cuts for the network.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Cut_Man_t * Abc_NtkSeqCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams )
+{
+/*
+    Cut_Man_t *  p;
+    Abc_Obj_t * pObj, * pNode;
+    int i, nIters, fStatus;
+    Vec_Int_t * vChoices;
+    int clk = clock();
+
+    assert( Abc_NtkIsSeq(pNtk) );
+    assert( pParams->fSeq );
+//    assert( Abc_NtkIsDfsOrdered(pNtk) );
+
+    // start the manager
+    pParams->nIdsMax = Abc_NtkObjNumMax( pNtk );
+    pParams->nCutSet = Abc_NtkCutSetNodeNum( pNtk );
+    p = Cut_ManStart( pParams );
+
+    // set cuts for the constant node and the PIs
+    pObj = Abc_AigConst1(pNtk);
+    if ( Abc_ObjFanoutNum(pObj) > 0 )
+        Cut_NodeSetTriv( p, pObj->Id );
+    Abc_NtkForEachPi( pNtk, pObj, i )
     {
-        pDriver = Abc_ObjFanin0(pObj);
-        if ( !Abc_ObjIsNode(pDriver) )
-            continue;
-        if ( Abc_NodeIsTravIdCurrent(pDriver) )
-            continue;
-        Abc_NodeSetTravIdCurrent(pDriver);
-        Cut_NodeSetComputedAsNew( p, pDriver->Id );
+//printf( "Setting trivial cut %d.\n", pObj->Id );
+        Cut_NodeSetTriv( p, pObj->Id );
+    }
+    // label the cutset nodes and set their number in the array
+    // assign the elementary cuts to the cutset nodes
+    Abc_SeqForEachCutsetNode( pNtk, pObj, i )
+    {
+        assert( pObj->fMarkC == 0 );
+        pObj->fMarkC = 1;
+        pObj->pCopy = (Abc_Obj_t *)i;
+        Cut_NodeSetTriv( p, pObj->Id );
+//printf( "Setting trivial cut %d.\n", pObj->Id );
     }
-    // compute as long as new cuts appear
 
+    // process the nodes
+    vChoices = Vec_IntAlloc( 100 );
+    for ( nIters = 0; nIters < 10; nIters++ )
+    {
+//printf( "ITERATION %d:\n", nIters );
+        // compute the cuts for the internal nodes
+        Abc_AigForEachAnd( pNtk, pObj, i )
+        {
+            Abc_NodeGetCutsSeq( p, pObj, nIters==0 );
+            // add cuts due to choices
+            if ( Abc_AigNodeIsChoice(pObj) )
+            {
+                Vec_IntClear( vChoices );
+                for ( pNode = pObj; pNode; pNode = pNode->pData )
+                    Vec_IntPush( vChoices, pNode->Id );
+                Cut_NodeUnionCutsSeq( p, vChoices, (pObj->fMarkC ? (int)pObj->pCopy : -1), nIters==0 );
+            }
+        }
+        // merge the new cuts with the old cuts
+        Abc_NtkForEachPi( pNtk, pObj, i )
+            Cut_NodeNewMergeWithOld( p, pObj->Id );
+        Abc_AigForEachAnd( pNtk, pObj, i )
+            Cut_NodeNewMergeWithOld( p, pObj->Id );
+        // for the cutset, transfer temp cuts to new cuts
+        fStatus = 0;
+        Abc_SeqForEachCutsetNode( pNtk, pObj, i )
+            fStatus |= Cut_NodeTempTransferToNew( p, pObj->Id, i );
+        if ( fStatus == 0 )
+            break;
+    }
+    Vec_IntFree( vChoices );
+
+    // if the status is not finished, transfer new to old for the cutset
+    Abc_SeqForEachCutsetNode( pNtk, pObj, i )
+        Cut_NodeNewMergeWithOld( p, pObj->Id );
 
+    // transfer the old cuts to the new positions
+    Abc_NtkForEachObj( pNtk, pObj, i )
+        Cut_NodeOldTransferToNew( p, pObj->Id );
+
+    // unlabel the cutset nodes
+    Abc_SeqForEachCutsetNode( pNtk, pObj, i )
+        pObj->fMarkC = 0;
+if ( pParams->fVerbose )
+{
+    Cut_ManPrintStats( p );
+PRT( "TOTAL ", clock() - clk );
+printf( "Converged after %d iterations.\n", nIters );
+}
+//Abc_NtkPrintCuts( p, pNtk, 1 );
     return p;
+*/
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes area.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NtkComputeArea( Abc_Ntk_t * pNtk, Cut_Man_t * p )
+{
+    Abc_Obj_t * pObj;
+    int Counter, i;
+    Counter = 0;
+    Abc_NtkForEachCo( pNtk, pObj, i )
+        Counter += Cut_ManMappingArea_rec( p, Abc_ObjFaninId0(pObj) );
+    return Counter;
 }
 
 /**Function*************************************************************
@@ -124,14 +324,14 @@ PRT( "Total", clock() - clk );
   SeeAlso     []
 
 ***********************************************************************/
-void * Abc_NodeGetCutsRecursive( void * p, Abc_Obj_t * pObj )
+void * Abc_NodeGetCutsRecursive( void * p, Abc_Obj_t * pObj, int fDag, int fTree )
 {
     void * pList;
     if ( pList = Abc_NodeReadCuts( p, pObj ) )
         return pList;
-    Abc_NodeGetCutsRecursive( p, Abc_ObjFanin0(pObj) );
-    Abc_NodeGetCutsRecursive( p, Abc_ObjFanin1(pObj) );
-    return Abc_NodeGetCuts( p, pObj );
+    Abc_NodeGetCutsRecursive( p, Abc_ObjFanin0(pObj), fDag, fTree );
+    Abc_NodeGetCutsRecursive( p, Abc_ObjFanin1(pObj), fDag, fTree );
+    return Abc_NodeGetCuts( p, pObj, fDag, fTree );
 }
 
 /**Function*************************************************************
@@ -145,10 +345,73 @@ void * Abc_NodeGetCutsRecursive( void * p, Abc_Obj_t * pObj )
   SeeAlso     []
 
 ***********************************************************************/
-void * Abc_NodeGetCuts( void * p, Abc_Obj_t * pObj )
+void * Abc_NodeGetCuts( void * p, Abc_Obj_t * pObj, int fDag, int fTree )
 {
+    Abc_Obj_t * pFanin;
+    int fDagNode, fTriv, TreeCode = 0;
+//    assert( Abc_NtkIsStrash(pObj->pNtk) );
+    assert( Abc_ObjFaninNum(pObj) == 2 );
+
+
+    // check if the node is a DAG node
+    fDagNode = (Abc_ObjFanoutNum(pObj) > 1 && !Abc_NodeIsMuxControlType(pObj));
+    // increment the counter of DAG nodes
+    if ( fDagNode ) Cut_ManIncrementDagNodes( p );
+    // add the trivial cut if the node is a DAG node, or if we compute all cuts
+    fTriv = fDagNode || !fDag;
+    // check if fanins are DAG nodes
+    if ( fTree )
+    {
+        pFanin = Abc_ObjFanin0(pObj);
+        TreeCode |=  (Abc_ObjFanoutNum(pFanin) > 1 && !Abc_NodeIsMuxControlType(pFanin));
+        pFanin = Abc_ObjFanin1(pObj);
+        TreeCode |= ((Abc_ObjFanoutNum(pFanin) > 1 && !Abc_NodeIsMuxControlType(pFanin)) << 1);
+    }
+
+
+    // changes due to the global/local cut computation
+    {
+        Cut_Params_t * pParams = Cut_ManReadParams(p);
+        if ( pParams->fLocal )
+        {
+            Vec_Int_t * vNodeAttrs = Cut_ManReadNodeAttrs(p);
+            fDagNode = Vec_IntEntry( vNodeAttrs, pObj->Id );
+            if ( fDagNode ) Cut_ManIncrementDagNodes( p );
+//            fTriv = fDagNode || !pParams->fGlobal;
+            fTriv = !Vec_IntEntry( vNodeAttrs, pObj->Id );
+            TreeCode = 0;
+            pFanin = Abc_ObjFanin0(pObj);
+            TreeCode |=  Vec_IntEntry( vNodeAttrs, pFanin->Id );
+            pFanin = Abc_ObjFanin1(pObj);
+            TreeCode |= (Vec_IntEntry( vNodeAttrs, pFanin->Id ) << 1);
+        }
+    }
     return Cut_NodeComputeCuts( p, pObj->Id, Abc_ObjFaninId0(pObj), Abc_ObjFaninId1(pObj),  
-        Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj) );  
+        Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj), fTriv, TreeCode );  
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the cuts for the network.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_NodeGetCutsSeq( void * p, Abc_Obj_t * pObj, int fTriv )
+{
+/*
+    int CutSetNum;
+    assert( Abc_NtkIsSeq(pObj->pNtk) );
+    assert( Abc_ObjFaninNum(pObj) == 2 );
+    fTriv     = pObj->fMarkC ? 0 : fTriv;
+    CutSetNum = pObj->fMarkC ? (int)pObj->pCopy : -1;
+    Cut_NodeComputeCutsSeq( p, pObj->Id, Abc_ObjFaninId0(pObj), Abc_ObjFaninId1(pObj),  
+        Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj), Seq_ObjFaninL0(pObj), Seq_ObjFaninL1(pObj), fTriv, CutSetNum );  
+*/
 }
 
 /**Function*************************************************************
@@ -164,7 +427,7 @@ void * Abc_NodeGetCuts( void * p, Abc_Obj_t * pObj )
 ***********************************************************************/
 void * Abc_NodeReadCuts( void * p, Abc_Obj_t * pObj )
 {
-    return Cut_NodeReadCuts( p, pObj->Id );  
+    return Cut_NodeReadCutsNew( p, pObj->Id );  
 }
 
 /**Function*************************************************************
@@ -183,6 +446,173 @@ void Abc_NodeFreeCuts( void * p, Abc_Obj_t * pObj )
     Cut_NodeFreeCuts( p, pObj->Id );
 }
 
+/**Function*************************************************************
+
+  Synopsis    [Computes the cuts for the network.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_NtkPrintCuts( void * p, Abc_Ntk_t * pNtk, int fSeq )
+{
+    Cut_Man_t * pMan = p;
+    Cut_Cut_t * pList;
+    Abc_Obj_t * pObj;
+    int i;
+    printf( "Cuts of the network:\n" );
+    Abc_NtkForEachObj( pNtk, pObj, i )
+    {
+        pList = Abc_NodeReadCuts( p, pObj );
+        printf( "Node %s:\n", Abc_ObjName(pObj) );
+        Cut_CutPrintList( pList, fSeq );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the cuts for the network.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Abc_NtkPrintCuts_( void * p, Abc_Ntk_t * pNtk, int fSeq )
+{
+    Cut_Man_t * pMan = p;
+    Cut_Cut_t * pList;
+    Abc_Obj_t * pObj;
+    pObj = Abc_NtkObj( pNtk, 2 * Abc_NtkObjNum(pNtk) / 3 );
+    pList = Abc_NodeReadCuts( p, pObj );
+    printf( "Node %s:\n", Abc_ObjName(pObj) );
+    Cut_CutPrintList( pList, fSeq );
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns global attributes randomly.]
+
+  Description [Old code.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t * Abc_NtkGetNodeAttributes( Abc_Ntk_t * pNtk ) 
+{
+    Vec_Int_t * vAttrs;
+//    Vec_Ptr_t * vNodes;
+    Abc_Obj_t * pObj;//, * pTemp;
+    int i;//, k;
+    int nNodesTotal = 0, nMffcsTotal = 0;
+    extern Vec_Ptr_t * Abc_NodeMffsInsideCollect( Abc_Obj_t * pNode );
+
+    vAttrs = Vec_IntStart( Abc_NtkObjNumMax(pNtk) + 1 );
+//    Abc_NtkForEachCi( pNtk, pObj, i )
+//        Vec_IntWriteEntry( vAttrs, pObj->Id, 1 );
+
+    Abc_NtkForEachObj( pNtk, pObj, i )
+    {
+        if ( Abc_ObjIsNode(pObj) )
+            nNodesTotal++;
+        if ( Abc_ObjIsCo(pObj) && Abc_ObjIsNode(Abc_ObjFanin0(pObj)) )
+            nMffcsTotal += Abc_NodeMffcSize( Abc_ObjFanin0(pObj) );
+//        if ( Abc_ObjIsNode(pObj) && (rand() % 4 == 0) )
+//        if ( Abc_ObjIsNode(pObj) && Abc_ObjFanoutNum(pObj) > 1 && !Abc_NodeIsMuxControlType(pObj) && (rand() % 3 == 0) )
+        if ( Abc_ObjIsNode(pObj) && Abc_ObjFanoutNum(pObj) > 1 && !Abc_NodeIsMuxControlType(pObj) )
+        {
+            int nMffc = Abc_NodeMffcSize(pObj);
+            nMffcsTotal += Abc_NodeMffcSize(pObj);
+//            printf( "%d ", nMffc );
+
+            if ( nMffc > 2 || Abc_ObjFanoutNum(pObj) > 8 )
+                Vec_IntWriteEntry( vAttrs, pObj->Id, 1 );
+        }
+    }
+/*
+    Abc_NtkForEachObj( pNtk, pObj, i )
+    {
+        if ( Vec_IntEntry( vAttrs, pObj->Id ) )
+        {
+            vNodes = Abc_NodeMffsInsideCollect( pObj );
+            Vec_PtrForEachEntry( vNodes, pTemp, k )
+                if ( pTemp != pObj )
+                    Vec_IntWriteEntry( vAttrs, pTemp->Id, 0 );
+            Vec_PtrFree( vNodes );
+        }
+    }
+*/
+    printf( "Total nodes = %d. Total MFFC nodes = %d.\n", nNodesTotal, nMffcsTotal );
+    return vAttrs; 
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns global attributes randomly.]
+
+  Description [Old code.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NtkSubDagSize_rec( Abc_Obj_t * pObj, Vec_Int_t * vAttrs ) 
+{
+    if ( Abc_NodeIsTravIdCurrent(pObj) )
+        return 0;
+    Abc_NodeSetTravIdCurrent(pObj);
+    if ( Vec_IntEntry( vAttrs, pObj->Id ) )
+        return 0;
+    if ( Abc_ObjIsCi(pObj) )
+        return 1;
+    assert( Abc_ObjFaninNum(pObj) == 2 );
+    return 1 + Abc_NtkSubDagSize_rec(Abc_ObjFanin0(pObj), vAttrs) +
+        Abc_NtkSubDagSize_rec(Abc_ObjFanin1(pObj), vAttrs);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns global attributes randomly.]
+
+  Description [Old code.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t * Abc_NtkGetNodeAttributes2( Abc_Ntk_t * pNtk ) 
+{
+    Vec_Int_t * vAttrs;
+    Abc_Obj_t * pObj;
+    int i, nSize;
+    assert( Abc_NtkIsDfsOrdered(pNtk) );
+    vAttrs = Vec_IntStart( Abc_NtkObjNumMax(pNtk) + 1 );
+    Abc_NtkForEachObj( pNtk, pObj, i )
+    {
+        // skip no-nodes and nodes without fanouts
+        if ( pObj->Id == 0 || !(Abc_ObjIsNode(pObj) && Abc_ObjFanoutNum(pObj) > 1 && !Abc_NodeIsMuxControlType(pObj)) )
+            continue;
+        // the node has more than one fanout - count its sub-DAG size
+        Abc_NtkIncrementTravId( pNtk );
+        nSize = Abc_NtkSubDagSize_rec( pObj, vAttrs );
+        if ( nSize > 15 )
+            Vec_IntWriteEntry( vAttrs, pObj->Id, 1 );
+    }
+    return vAttrs; 
+}
+
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
 ////////////////////////////////////////////////////////////////////////