Improved buffering.

9 files changed, 334 insertions, 337 deletions

diff --git a/abclib.dsp b/abclib.dsp
index c31121ed..909bfbfe 100644
--- a/abclib.dsp
+++ b/abclib.dsp
@@ -2451,10 +2451,6 @@ SOURCE=.\src\map\scl\scl.h
 # End Source File
 # Begin Source File
 
-SOURCE=.\src\map\scl\sclBuff.c
-# End Source File
-# Begin Source File
-
 SOURCE=.\src\map\scl\sclBuffer.c
 # End Source File
 # Begin Source File
diff --git a/src/map/mapper/mapperMatch.c b/src/map/mapper/mapperMatch.c
index a59af3d3..f062e4da 100644
--- a/src/map/mapper/mapperMatch.c
+++ b/src/map/mapper/mapperMatch.c
@@ -200,7 +200,7 @@ int Map_MatchNodePhase( Map_Man_t * p, Map_Node_t * pNode, int fPhase )
     for ( pCut = pNode->pCuts->pNext; pCut; pCut = pCut->pNext )
     {
         // limit gate sizes based on fanout count
-        if ( (pNode->nRefs > 8 && pCut->nLeaves > 2) || (pNode->nRefs > 4 && pCut->nLeaves > 3) )
+        if ( (pNode->nRefs > 3 && pCut->nLeaves > 2) || (pNode->nRefs > 1 && pCut->nLeaves > 3) )
             continue;
         pMatch = pCut->M + fPhase;
         if ( pMatch->pSupers == NULL )
diff --git a/src/map/scl/module.make b/src/map/scl/module.make
index 12f30ae1..6063a3de 100644
--- a/src/map/scl/module.make
+++ b/src/map/scl/module.make
@@ -1,5 +1,4 @@
 SRC +=  src/map/scl/scl.c \
-    src/map/scl/sclBuff.c \
     src/map/scl/sclBuffer.c \
     src/map/scl/sclDnsize.c \
     src/map/scl/sclLib.c \
diff --git a/src/map/scl/scl.c b/src/map/scl/scl.c
index ea8731c4..23457f7c 100644
--- a/src/map/scl/scl.c
+++ b/src/map/scl/scl.c
@@ -554,14 +554,15 @@ int Scl_CommandBuffer( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
     Abc_Ntk_t * pNtk = Abc_FrameReadNtk(pAbc);
     Abc_Ntk_t * pNtkRes;
-    int Degree, fUseInvs;
+    int FanMin, FanMax, fUseInvs;
     int c, fVerbose;
     int fOldAlgo = 0;
-    Degree   = 4;
-    fUseInvs = 0;
-    fVerbose = 0;
+    FanMin   =  6;
+    FanMax   = 14;
+    fUseInvs =  0;
+    fVerbose =  0;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "Naivh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "NMaivh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -571,9 +572,20 @@ int Scl_CommandBuffer( Abc_Frame_t * pAbc, int argc, char ** argv )
                 Abc_Print( -1, "Command line switch \"-N\" should be followed by a positive integer.\n" );
                 goto usage;
             }
-            Degree = atoi(argv[globalUtilOptind]);
+            FanMin = atoi(argv[globalUtilOptind]);
             globalUtilOptind++;
-            if ( Degree < 0 ) 
+            if ( FanMin < 0 ) 
+                goto usage;
+            break;
+        case 'M':
+            if ( globalUtilOptind >= argc )
+            {
+                Abc_Print( -1, "Command line switch \"-M\" should be followed by a positive integer.\n" );
+                goto usage;
+            }
+            FanMax = atoi(argv[globalUtilOptind]);
+            globalUtilOptind++;
+            if ( FanMax < 0 ) 
                 goto usage;
             break;
         case 'a':
@@ -605,9 +617,9 @@ int Scl_CommandBuffer( Abc_Frame_t * pAbc, int argc, char ** argv )
 
     // modify the current network
     if ( fOldAlgo )
-        pNtkRes = Abc_SclPerformBuffering( pNtk, Degree, fUseInvs, fVerbose );
+        pNtkRes = Abc_SclPerformBuffering( pNtk, FanMax, fUseInvs, fVerbose );
     else
-        pNtkRes = Abc_SclBufPerform( pNtk, fVerbose );
+        pNtkRes = Abc_SclBufPerform( pNtk, FanMin, FanMax, fVerbose );
     if ( pNtkRes == NULL )
     {
         Abc_Print( -1, "The command has failed.\n" );
@@ -618,9 +630,10 @@ int Scl_CommandBuffer( Abc_Frame_t * pAbc, int argc, char ** argv )
     return 0;
 
 usage:
-    fprintf( pAbc->Err, "usage: buffer [-N num] [-aivh]\n" );
+    fprintf( pAbc->Err, "usage: buffer [-NM num] [-aivh]\n" );
     fprintf( pAbc->Err, "\t           performs buffering of the mapped network\n" );
-    fprintf( pAbc->Err, "\t-N <num> : the max allowed fanout count of node/buffer [default = %d]\n", Degree );
+    fprintf( pAbc->Err, "\t-N <num> : the min fanout considered by the algorithm [default = %d]\n", FanMin );
+    fprintf( pAbc->Err, "\t-M <num> : the max allowed fanout count of node/buffer [default = %d]\n", FanMax );
     fprintf( pAbc->Err, "\t-a       : toggle using old algorithm [default = %s]\n", fOldAlgo? "yes": "no" );
     fprintf( pAbc->Err, "\t-i       : toggle using interters instead of buffers [default = %s]\n", fUseInvs? "yes": "no" );
     fprintf( pAbc->Err, "\t-v       : toggle printing verbose information [default = %s]\n", fVerbose? "yes": "no" );
diff --git a/src/map/scl/sclBuff.c b/src/map/scl/sclBuff.c
deleted file mode 100644
index a26b0f87..00000000
--- a/src/map/scl/sclBuff.c
+++ /dev/null
@@ -1,238 +0,0 @@
-/**CFile****************************************************************
-
-  FileName    [sclBuff.c]
-
-  SystemName  [ABC: Logic synthesis and verification system.]
-
-  PackageName [Standard-cell library representation.]
-
-  Synopsis    [Buffering algorithms.]
-
-  Author      [Alan Mishchenko, Niklas Een]
-  
-  Affiliation [UC Berkeley]
-
-  Date        [Ver. 1.0. Started - August 24, 2012.]
-
-  Revision    [$Id: sclBuff.c,v 1.0 2012/08/24 00:00:00 alanmi Exp $]
-
-***********************************************************************/
-
-#include "sclSize.h"
-#include "map/mio/mio.h"
-
-ABC_NAMESPACE_IMPL_START
-
-
-////////////////////////////////////////////////////////////////////////
-///                        DECLARATIONS                              ///
-////////////////////////////////////////////////////////////////////////
-
-////////////////////////////////////////////////////////////////////////
-///                     FUNCTION DEFINITIONS                         ///
-////////////////////////////////////////////////////////////////////////
-
-/**Function*************************************************************
-
-  Synopsis    [Make sure the network is in topo order without dangling nodes.]
-
-  Description [Returns 1 iff the network is fine.]
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-int Abc_SclCheckNtk( Abc_Ntk_t * p, int fVerbose )
-{
-    Abc_Obj_t * pObj, * pFanin;
-    int i, k, fFlag = 1;
-    Abc_NtkIncrementTravId( p );        
-    Abc_NtkForEachCi( p, pObj, i )
-        Abc_NodeSetTravIdCurrent( pObj );
-    Abc_NtkForEachNode( p, pObj, i )
-    {
-        Abc_ObjForEachFanin( pObj, pFanin, k )
-            if ( !Abc_NodeIsTravIdCurrent( pFanin ) )
-                printf( "obj %d and its fanin %d are not in the topo order\n", Abc_ObjId(pObj), Abc_ObjId(pFanin) ), fFlag = 0;
-        Abc_NodeSetTravIdCurrent( pObj );
-        if ( Abc_ObjFanoutNum(pObj) == 0 )
-            printf( "node %d has no fanout\n", Abc_ObjId(pObj) ), fFlag = 0;
-        if ( !fFlag )
-            break;
-    }
-    if ( fFlag && fVerbose )
-        printf( "The network is in topo order and no dangling nodes.\n" );
-    return fFlag;
-}
-
-/**Function*************************************************************
-
-  Synopsis    []
-
-  Description []
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-int Abc_SclCheckNtk2( Abc_Ntk_t * p )
-{
-    Abc_Obj_t * pObj, * pFanout;
-    int i, k;
-    Abc_NtkStartReverseLevels( p, 0 );
-    Abc_NtkForEachNode( p, pObj, i )
-    {
-        if ( Abc_ObjFanoutNum(pObj) <= 3 )
-            continue;
-        printf( "Node %5d (%2d) : fans = %3d  ", i, Abc_ObjLevel(pObj), Abc_ObjFanoutNum(pObj) );
-        Abc_ObjForEachFanout( pObj, pFanout, k )
-            printf( "%d ", Abc_ObjReverseLevel(pFanout) );
-        printf( "\n" );
-    }
-    return 1;
-}
-
-/**Function*************************************************************
-
-  Synopsis    [Performs buffering of the mapped network.]
-
-  Description []
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-int Abc_NodeCompareLevels( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
-{
-    int Diff = Abc_ObjLevel(*pp1) - Abc_ObjLevel(*pp2);
-    if ( Diff < 0 )
-        return -1;
-    if ( Diff > 0 ) 
-        return 1;
-    Diff = (*pp1)->Id - (*pp2)->Id; // needed to make qsort() platform-infependent
-    if ( Diff < 0 )
-        return -1;
-    if ( Diff > 0 ) 
-        return 1;
-    return 0; 
-}
-int Abc_SclComputeReverseLevel( Abc_Obj_t * pObj )
-{
-    Abc_Obj_t * pFanout;
-    int i, Level = 0;
-    Abc_ObjForEachFanout( pObj, pFanout, i )
-        Level = Abc_MaxInt( Level, pFanout->Level );
-    return Level + 1;
-}
-Abc_Obj_t * Abc_SclPerformBufferingOne( Abc_Obj_t * pObj, int Degree, int fUseInvs, int fVerbose )
-{
-    Vec_Ptr_t * vFanouts;
-    Abc_Obj_t * pBuffer, * pFanout;
-    int i, Degree0 = Degree;
-    assert( Abc_ObjFanoutNum(pObj) > Degree );
-    // collect fanouts and sort by reverse level
-    vFanouts = Vec_PtrAlloc( Abc_ObjFanoutNum(pObj) );
-    Abc_NodeCollectFanouts( pObj, vFanouts );
-    Vec_PtrSort( vFanouts, (int (*)(void))Abc_NodeCompareLevels );
-    // select the first Degree fanouts
-    if ( fUseInvs )
-        pBuffer = Abc_NtkCreateNodeInv( pObj->pNtk, NULL );
-    else
-        pBuffer = Abc_NtkCreateNodeBuf( pObj->pNtk, NULL );
-    // check if it is possible to not increase level
-    if ( Vec_PtrSize(vFanouts) < 2 * Degree )
-    {
-        Abc_Obj_t * pFanPrev = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Vec_PtrSize(vFanouts)-1-Degree);
-        Abc_Obj_t * pFanThis = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Degree-1);
-        Abc_Obj_t * pFanLast = (Abc_Obj_t *)Vec_PtrEntryLast(vFanouts);
-        if ( Abc_ObjLevel(pFanThis) == Abc_ObjLevel(pFanLast) &&
-             Abc_ObjLevel(pFanPrev) <  Abc_ObjLevel(pFanThis) )
-        {
-            // find the first one whose level is the same as last
-            Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
-                if ( Abc_ObjLevel(pFanout) == Abc_ObjLevel(pFanLast) )
-                    break;
-            assert( i < Vec_PtrSize(vFanouts) );
-            if ( i > 1 )
-                Degree = i;
-        }
-        // make the last two more well-balanced
-        if ( Degree == Degree0 && Degree > Vec_PtrSize(vFanouts) - Degree )
-            Degree = Vec_PtrSize(vFanouts)/2 + (Vec_PtrSize(vFanouts) & 1);
-        assert( Degree <= Degree0 );
-    }
-    // select fanouts
-    Vec_PtrForEachEntryStop( Abc_Obj_t *, vFanouts, pFanout, i, Degree )
-        Abc_ObjPatchFanin( pFanout, pObj, pBuffer );
-    if ( fVerbose )
-    {
-        printf( "%5d : ", Abc_ObjId(pObj) );
-        Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
-            printf( "%d%s ", Abc_ObjLevel(pFanout), i == Degree-1 ? "  " : "" );
-        printf( "\n" );
-    }
-    Vec_PtrFree( vFanouts );
-    Abc_ObjAddFanin( pBuffer, pObj );
-    pBuffer->Level = Abc_SclComputeReverseLevel( pBuffer );
-    return pBuffer;
-}
-void Abc_SclPerformBuffering_rec( Abc_Obj_t * pObj, int Degree, int fUseInvs, int fVerbose )
-{
-    Abc_Obj_t * pFanout;
-    int i;
-    if ( Abc_NodeIsTravIdCurrent( pObj ) )
-        return;
-    Abc_NodeSetTravIdCurrent( pObj );
-    pObj->Level = 0;
-    if ( Abc_ObjIsCo(pObj) )
-        return;
-    assert( Abc_ObjIsCi(pObj) || Abc_ObjIsNode(pObj) );
-    // buffer fanouts and collect reverse levels
-    Abc_ObjForEachFanout( pObj, pFanout, i )
-        Abc_SclPerformBuffering_rec( pFanout, Degree, fUseInvs, fVerbose );
-    // perform buffering as long as needed
-    while ( Abc_ObjFanoutNum(pObj) > Degree )
-        Abc_SclPerformBufferingOne( pObj, Degree, fUseInvs, fVerbose );
-    // compute the new level of the node
-    pObj->Level = Abc_SclComputeReverseLevel( pObj );
-}
-Abc_Ntk_t * Abc_SclPerformBuffering( Abc_Ntk_t * p, int Degree, int fUseInvs, int fVerbose )
-{
-    Vec_Int_t * vCiLevs;
-    Abc_Ntk_t * pNew;
-    Abc_Obj_t * pObj;
-    int i;
-    assert( Abc_NtkHasMapping(p) );
-    if ( fUseInvs )
-        printf( "Warning!!! Using inverters instead of buffers.\n" );
-    // remember CI levels
-    vCiLevs = Vec_IntAlloc( Abc_NtkCiNum(p) );
-    Abc_NtkForEachCi( p, pObj, i )
-        Vec_IntPush( vCiLevs, Abc_ObjLevel(pObj) );
-    // perform buffering
-    Abc_NtkIncrementTravId( p );        
-    Abc_NtkForEachCi( p, pObj, i )
-        Abc_SclPerformBuffering_rec( pObj, Degree, fUseInvs, fVerbose );
-    // recompute logic levels
-    Abc_NtkForEachCi( p, pObj, i )
-        pObj->Level = Vec_IntEntry( vCiLevs, i );
-    Abc_NtkForEachNode( p, pObj, i )
-        Abc_ObjLevelNew( pObj );
-    Vec_IntFree( vCiLevs );
-    // duplication in topo order
-    pNew = Abc_NtkDupDfs( p );
-    Abc_SclCheckNtk( pNew, fVerbose );
-//    Abc_NtkDelete( pNew );
-    return pNew;
-}
-
-////////////////////////////////////////////////////////////////////////
-///                       END OF FILE                                ///
-////////////////////////////////////////////////////////////////////////
-
-
-ABC_NAMESPACE_IMPL_END
-
diff --git a/src/map/scl/sclBuffer.c b/src/map/scl/sclBuffer.c
index f25ea277..d9afdbe5 100644
--- a/src/map/scl/sclBuffer.c
+++ b/src/map/scl/sclBuffer.c
@@ -59,6 +59,7 @@ struct Buf_Man_t_
     int            nDuplicate;
     int            nBranch0;
     int            nBranch1;
+    int            nBranchCrit;
 };
 
 static inline int  Abc_BufNodeArr( Buf_Man_t * p, Abc_Obj_t * pObj )                     { return Vec_IntEntry( p->vArr, Abc_ObjId(pObj) );                                   }
@@ -76,6 +77,177 @@ static inline int  Abc_BufEdgeSlack( Buf_Man_t * p, Abc_Obj_t * pObj, Abc_Obj_t
 
 /**Function*************************************************************
 
+  Synopsis    [Make sure the network is in topo order without dangling nodes.]
+
+  Description [Returns 1 iff the network is fine.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_SclCheckNtk( Abc_Ntk_t * p, int fVerbose )
+{
+    Abc_Obj_t * pObj, * pFanin;
+    int i, k, fFlag = 1;
+    Abc_NtkIncrementTravId( p );        
+    Abc_NtkForEachCi( p, pObj, i )
+        Abc_NodeSetTravIdCurrent( pObj );
+    Abc_NtkForEachNode( p, pObj, i )
+    {
+        Abc_ObjForEachFanin( pObj, pFanin, k )
+            if ( !Abc_NodeIsTravIdCurrent( pFanin ) )
+                printf( "obj %d and its fanin %d are not in the topo order\n", Abc_ObjId(pObj), Abc_ObjId(pFanin) ), fFlag = 0;
+        Abc_NodeSetTravIdCurrent( pObj );
+        if ( Abc_ObjFanoutNum(pObj) == 0 )
+            printf( "node %d has no fanout\n", Abc_ObjId(pObj) ), fFlag = 0;
+        if ( !fFlag )
+            break;
+    }
+    if ( fFlag && fVerbose )
+        printf( "The network is in topo order and no dangling nodes.\n" );
+    return fFlag;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs buffering of the mapped network (old code).]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeCompareLevels( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
+{
+    int Diff = Abc_ObjLevel(*pp1) - Abc_ObjLevel(*pp2);
+    if ( Diff < 0 )
+        return -1;
+    if ( Diff > 0 ) 
+        return 1;
+    Diff = (*pp1)->Id - (*pp2)->Id; // needed to make qsort() platform-infependent
+    if ( Diff < 0 )
+        return -1;
+    if ( Diff > 0 ) 
+        return 1;
+    return 0; 
+}
+int Abc_SclComputeReverseLevel( Abc_Obj_t * pObj )
+{
+    Abc_Obj_t * pFanout;
+    int i, Level = 0;
+    Abc_ObjForEachFanout( pObj, pFanout, i )
+        Level = Abc_MaxInt( Level, pFanout->Level );
+    return Level + 1;
+}
+Abc_Obj_t * Abc_SclPerformBufferingOne( Abc_Obj_t * pObj, int Degree, int fUseInvs, int fVerbose )
+{
+    Vec_Ptr_t * vFanouts;
+    Abc_Obj_t * pBuffer, * pFanout;
+    int i, Degree0 = Degree;
+    assert( Abc_ObjFanoutNum(pObj) > Degree );
+    // collect fanouts and sort by reverse level
+    vFanouts = Vec_PtrAlloc( Abc_ObjFanoutNum(pObj) );
+    Abc_NodeCollectFanouts( pObj, vFanouts );
+    Vec_PtrSort( vFanouts, (int (*)(void))Abc_NodeCompareLevels );
+    // select the first Degree fanouts
+    if ( fUseInvs )
+        pBuffer = Abc_NtkCreateNodeInv( pObj->pNtk, NULL );
+    else
+        pBuffer = Abc_NtkCreateNodeBuf( pObj->pNtk, NULL );
+    // check if it is possible to not increase level
+    if ( Vec_PtrSize(vFanouts) < 2 * Degree )
+    {
+        Abc_Obj_t * pFanPrev = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Vec_PtrSize(vFanouts)-1-Degree);
+        Abc_Obj_t * pFanThis = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Degree-1);
+        Abc_Obj_t * pFanLast = (Abc_Obj_t *)Vec_PtrEntryLast(vFanouts);
+        if ( Abc_ObjLevel(pFanThis) == Abc_ObjLevel(pFanLast) &&
+             Abc_ObjLevel(pFanPrev) <  Abc_ObjLevel(pFanThis) )
+        {
+            // find the first one whose level is the same as last
+            Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
+                if ( Abc_ObjLevel(pFanout) == Abc_ObjLevel(pFanLast) )
+                    break;
+            assert( i < Vec_PtrSize(vFanouts) );
+            if ( i > 1 )
+                Degree = i;
+        }
+        // make the last two more well-balanced
+        if ( Degree == Degree0 && Degree > Vec_PtrSize(vFanouts) - Degree )
+            Degree = Vec_PtrSize(vFanouts)/2 + (Vec_PtrSize(vFanouts) & 1);
+        assert( Degree <= Degree0 );
+    }
+    // select fanouts
+    Vec_PtrForEachEntryStop( Abc_Obj_t *, vFanouts, pFanout, i, Degree )
+        Abc_ObjPatchFanin( pFanout, pObj, pBuffer );
+    if ( fVerbose )
+    {
+        printf( "%5d : ", Abc_ObjId(pObj) );
+        Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
+            printf( "%d%s ", Abc_ObjLevel(pFanout), i == Degree-1 ? "  " : "" );
+        printf( "\n" );
+    }
+    Vec_PtrFree( vFanouts );
+    Abc_ObjAddFanin( pBuffer, pObj );
+    pBuffer->Level = Abc_SclComputeReverseLevel( pBuffer );
+    return pBuffer;
+}
+void Abc_SclPerformBuffering_rec( Abc_Obj_t * pObj, int Degree, int fUseInvs, int fVerbose )
+{
+    Abc_Obj_t * pFanout;
+    int i;
+    if ( Abc_NodeIsTravIdCurrent( pObj ) )
+        return;
+    Abc_NodeSetTravIdCurrent( pObj );
+    pObj->Level = 0;
+    if ( Abc_ObjIsCo(pObj) )
+        return;
+    assert( Abc_ObjIsCi(pObj) || Abc_ObjIsNode(pObj) );
+    // buffer fanouts and collect reverse levels
+    Abc_ObjForEachFanout( pObj, pFanout, i )
+        Abc_SclPerformBuffering_rec( pFanout, Degree, fUseInvs, fVerbose );
+    // perform buffering as long as needed
+    while ( Abc_ObjFanoutNum(pObj) > Degree )
+        Abc_SclPerformBufferingOne( pObj, Degree, fUseInvs, fVerbose );
+    // compute the new level of the node
+    pObj->Level = Abc_SclComputeReverseLevel( pObj );
+}
+Abc_Ntk_t * Abc_SclPerformBuffering( Abc_Ntk_t * p, int Degree, int fUseInvs, int fVerbose )
+{
+    Vec_Int_t * vCiLevs;
+    Abc_Ntk_t * pNew;
+    Abc_Obj_t * pObj;
+    int i;
+    assert( Abc_NtkHasMapping(p) );
+    if ( fUseInvs )
+        printf( "Warning!!! Using inverters instead of buffers.\n" );
+    // remember CI levels
+    vCiLevs = Vec_IntAlloc( Abc_NtkCiNum(p) );
+    Abc_NtkForEachCi( p, pObj, i )
+        Vec_IntPush( vCiLevs, Abc_ObjLevel(pObj) );
+    // perform buffering
+    Abc_NtkIncrementTravId( p );        
+    Abc_NtkForEachCi( p, pObj, i )
+        Abc_SclPerformBuffering_rec( pObj, Degree, fUseInvs, fVerbose );
+    // recompute logic levels
+    Abc_NtkForEachCi( p, pObj, i )
+        pObj->Level = Vec_IntEntry( vCiLevs, i );
+    Abc_NtkForEachNode( p, pObj, i )
+        Abc_ObjLevelNew( pObj );
+    Vec_IntFree( vCiLevs );
+    // duplication in topo order
+    pNew = Abc_NtkDupDfs( p );
+    Abc_SclCheckNtk( pNew, fVerbose );
+//    Abc_NtkDelete( pNew );
+    return pNew;
+}
+
+
+
+/**Function*************************************************************
+
   Synopsis    []
 
   Description []
@@ -134,8 +306,10 @@ void Abc_BufAddToQue( Buf_Man_t * p, Abc_Obj_t * pObj )
     if ( Abc_ObjFanoutNum(pObj) < p->nFanMin )
         return;
     Vec_FltWriteEntry( p->vCounts, Abc_ObjId(pObj), Abc_ObjFanoutNum(pObj) );
-    assert( !Vec_QueIsMember(p->vQue, Abc_ObjId(pObj)) );
-    Vec_QuePush( p->vQue, Abc_ObjId(pObj) );
+    if ( Vec_QueIsMember(p->vQue, Abc_ObjId(pObj)) )
+        Vec_QueUpdate( p->vQue, Abc_ObjId(pObj) );
+    else
+        Vec_QuePush( p->vQue, Abc_ObjId(pObj) );
 }
 
 
@@ -241,7 +415,7 @@ void Abc_BufUpdateDep( Buf_Man_t * p, Abc_Obj_t * pObj )
   SeeAlso     []
 
 ***********************************************************************/
-Buf_Man_t * Buf_ManStart( Abc_Ntk_t * pNtk )
+Buf_Man_t * Buf_ManStart( Abc_Ntk_t * pNtk, int FanMin, int FanMax )
 {
     Buf_Man_t * p;
     Abc_Obj_t * pObj;
@@ -249,8 +423,8 @@ Buf_Man_t * Buf_ManStart( Abc_Ntk_t * pNtk )
     int i;
     p = ABC_CALLOC( Buf_Man_t, 1 );
     p->pNtk      = pNtk;
-    p->nFanMin   = 6;
-//    p->nFanMax   = 16;
+    p->nFanMin   = FanMin;
+    p->nFanMax   = FanMax;
     // allocate arrays
     p->nObjStart = Abc_NtkObjNumMax(p->pNtk);
     p->nObjAlloc = (6 * Abc_NtkObjNumMax(p->pNtk) / 3) + 100;
@@ -279,15 +453,14 @@ Buf_Man_t * Buf_ManStart( Abc_Ntk_t * pNtk )
     Vec_PtrForEachEntryReverse( Abc_Obj_t *, vNodes, pObj, i )
         Abc_BufComputeDep( p, pObj );
     Abc_BufUpdateGlobal( p );
+//    Abc_NtkForEachNode( p->pNtk, pObj, i )
+//        printf( "%4d : %4d %4d\n", i, Abc_BufNodeArr(p, pObj), Abc_BufNodeDep(p, pObj) );
     // create fanout queue
     Abc_NtkForEachCi( p->pNtk, pObj, i )
         Abc_BufAddToQue( p, pObj );
     Vec_PtrForEachEntry( Abc_Obj_t *, vNodes, pObj, i )
         Abc_BufAddToQue( p, pObj );
     Vec_PtrFree( vNodes );
-    // print everything
-//    Abc_NtkForEachNode( p->pNtk, pObj, i )
-//        printf( "%4d : %4d %4d\n", i, Abc_BufNodeArr(p, pObj), Abc_BufNodeDep(p, pObj) );
     p->vDelays  = Vec_IntAlloc( 100 );
     p->vOrder   = Vec_IntAlloc( 100 );
     p->vNonCrit = Vec_IntAlloc( 100 );
@@ -297,8 +470,8 @@ Buf_Man_t * Buf_ManStart( Abc_Ntk_t * pNtk )
 }
 void Buf_ManStop( Buf_Man_t * p )
 {
-    printf( "Sep = %d. Dup = %d. Br0 = %d. Br1 = %d.   ", 
-        p->nSeparate, p->nDuplicate, p->nBranch0, p->nBranch1 );
+    printf( "Sep = %d. Dup = %d. Br0 = %d. Br1 = %d. BrC = %d.  ", 
+        p->nSeparate, p->nDuplicate, p->nBranch0, p->nBranch1, p->nBranchCrit );
     printf( "Orig = %d. Add = %d. Rem = %d.\n", 
         p->nObjStart, Abc_NtkObjNumMax(p->pNtk) - p->nObjStart, 
         p->nObjAlloc - Abc_NtkObjNumMax(p->pNtk) );
@@ -337,17 +510,14 @@ Vec_Int_t * Abc_BufSortByDelay( Buf_Man_t * p, int iPivot )
     Abc_ObjForEachFanout( pObj, pFanout, i )
     {
         int Slack = Abc_BufEdgeSlack(p, pObj, pFanout);
-        if ( Slack < 0 )
-            printf( "%d  ", Slack );
+        assert( Slack >= 0 );
         Vec_IntPush( p->vDelays, Abc_MaxInt(0, Slack) );
     }
     pOrder = Abc_QuickSortCost( Vec_IntArray(p->vDelays), Vec_IntSize(p->vDelays), 0 );
-//Vec_IntPrint( p->vDelays );
     Vec_IntClear( p->vOrder );
     for ( i = 0; i < Vec_IntSize(p->vDelays); i++ )
         Vec_IntPush( p->vOrder, Abc_ObjId(Abc_ObjFanout(pObj, pOrder[i])) );
     ABC_FREE( pOrder );
-    // print
 //    for ( i = 0; i < Vec_IntSize(p->vDelays); i++ )
 //        printf( "%5d - %5d   ", Vec_IntEntry(p->vOrder, i), Abc_BufEdgeSlack(p, pObj, Abc_NtkObj(p->pNtk, Vec_IntEntry(p->vOrder, i))) );
     return p->vOrder;        
@@ -379,6 +549,34 @@ void Abc_BufPrintOne( Buf_Man_t * p, int iPivot )
   SeeAlso     []
 
 ***********************************************************************/
+void Abc_BufReplaceBufsByInvs( Abc_Ntk_t * pNtk )
+{
+    Abc_Obj_t * pObj, * pInv;
+    int i, Counter = 0;
+    Abc_NtkForEachNode( pNtk, pObj, i )
+    {
+        if ( !Abc_NodeIsBuf(pObj) )
+            continue;
+        assert( pObj->pData == Mio_LibraryReadBuf((Mio_Library_t *)pNtk->pManFunc) );
+        pObj->pData = Mio_LibraryReadInv((Mio_Library_t *)pNtk->pManFunc);
+        pInv = Abc_NtkCreateNodeInv( pNtk, Abc_ObjFanin0(pObj) );
+        Abc_ObjPatchFanin( pObj, Abc_ObjFanin0(pObj), pInv );
+        Counter++;
+    }
+    printf( "Replaced %d buffers by invertor pairs.\n", Counter );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
 int Abc_BufComputeAverage( Buf_Man_t * p, int iPivot, Vec_Int_t * vOrder )
 {
     Abc_Obj_t * pObj, * pFanout;
@@ -388,17 +586,6 @@ int Abc_BufComputeAverage( Buf_Man_t * p, int iPivot, Vec_Int_t * vOrder )
         Average += Abc_BufEdgeSlack( p, pObj, pFanout );
     return Average / Vec_IntSize(vOrder);
 }
-int Abc_BufCountNonCritical_( Buf_Man_t * p, int iPivot, Vec_Int_t * vOrder )
-{
-    Abc_Obj_t * pObj, * pFanout;
-    int i;
-    Vec_IntClear( p->vNonCrit );
-    pObj = Abc_NtkObj( p->pNtk, iPivot );
-    Abc_NtkForEachObjVec( vOrder, p->pNtk, pFanout, i )
-        if ( Abc_BufEdgeSlack( p, pObj, pFanout ) > 5*BUF_SCALE/2 )
-            Vec_IntPush( p->vNonCrit, Abc_ObjId(pFanout) );
-    return Vec_IntSize(p->vNonCrit);
-}
 Abc_Obj_t * Abc_BufFindNonBuffDriver( Buf_Man_t * p, Abc_Obj_t * pObj )
 {
     return (Abc_ObjIsNode(pObj) && Abc_NodeIsBuf(pObj)) ? Abc_BufFindNonBuffDriver(p, Abc_ObjFanin0(pObj)) : pObj;
@@ -421,35 +608,30 @@ int Abc_BufCountNonCritical( Buf_Man_t * p, Abc_Obj_t * pObj )
     int i;
     Vec_IntClear( p->vNonCrit );
     Abc_ObjForEachFanout( pObj, pFanout, i )
-        if ( Abc_BufEdgeSlack( p, pObj, pFanout ) > 3*BUF_SCALE )
+        if ( Abc_BufEdgeSlack( p, pObj, pFanout ) > 5*BUF_SCALE/2 )
             Vec_IntPush( p->vNonCrit, Abc_ObjId(pFanout) );
     return Vec_IntSize(p->vNonCrit);
 }
 void Abc_BufPerformOne( Buf_Man_t * p, int iPivot, int fVerbose )
 {
     Abc_Obj_t * pObj, * pFanout;
-    Vec_Int_t * vOrder;
-    int Fastest, Slowest, Average;
     int i, j, nCrit, nNonCrit;
     int DelayMax = p->DelayMax;
+    assert( Abc_NtkObjNumMax(p->pNtk) + 30 < p->nObjAlloc );
     pObj     = Abc_NtkObj( p->pNtk, iPivot );
+//    assert( Vec_FltEntry(p->vCounts, iPivot) == (float)Abc_ObjFanoutNum(pObj) );
     nNonCrit = Abc_BufCountNonCritical( p, pObj );
     nCrit    = Abc_ObjFanoutNum(pObj) - nNonCrit;
 if ( fVerbose )
 {
-vOrder = Abc_BufSortByDelay( p, iPivot );
 //Abc_BufPrintOne( p, iPivot );
-Fastest  = Abc_BufEdgeSlack( p, pObj, Abc_NtkObj(p->pNtk, Vec_IntEntry(vOrder,0)) );
-Slowest  = Abc_BufEdgeSlack( p, pObj, Abc_NtkObj(p->pNtk, Vec_IntEntryLast(vOrder)) );
-Average  = Abc_BufComputeAverage( p, iPivot, vOrder );
-printf( "FI =%2d. FO =%4d. ", Abc_ObjFaninNum(pObj), Abc_ObjFanoutNum(pObj) );
-printf( "Fastest =%5d. Slowest =%5d. Ave =%5d.  Crit =%3d. NonCrit =%3d.  ", Fastest, Slowest, Average, nCrit, nNonCrit );
+printf( "ObjId = %6d : %-10s   FI = %d. FO =%4d.  Crit =%4d.  ", 
+    Abc_ObjId(pObj), Mio_GateReadName((Mio_Gate_t *)pObj->pData), Abc_ObjFaninNum(pObj), Abc_ObjFanoutNum(pObj), nCrit );
 }
-    // decide based on these
-    assert( Abc_NtkObjNumMax(p->pNtk) + 30 < p->nObjAlloc );
+    // consider three cases
     if ( nCrit > 0 && nNonCrit > 1 )
     {
-        // separate using buffer
+        // (1) both critical and non-critical are present - split them by adding buffer
         Abc_Obj_t * pBuffer = Abc_NtkCreateNodeBuf( p->pNtk, pObj );
         Abc_NtkForEachObjVec( p->vNonCrit, p->pNtk, pFanout, i )
             Abc_ObjPatchFanin( pFanout, pObj, pBuffer );
@@ -463,10 +645,9 @@ printf( "Fastest =%5d. Slowest =%5d. Ave =%5d.  Crit =%3d. NonCrit =%3d.  ", Fas
 if ( fVerbose )
 printf( "Adding buffer\n" );
     }
-
-    else if ( nNonCrit < 2 && Abc_ObjFanoutNum(pObj) > 4 && Abc_ObjFanoutNum(pObj) < 12 && Abc_ObjIsNode(pObj) )
+    else if ( nCrit > 0 && Abc_ObjIsNode(pObj) && Abc_ObjFanoutNum(pObj) > p->nFanMin )//&& Abc_ObjFaninNum(pObj) < 2 )
     {
-        // duplicate
+        // (2) only critical are present - duplicate
         Abc_Obj_t * pClone = Abc_NtkDupObj( p->pNtk, pObj, 0 );
         Abc_ObjForEachFanin( pObj, pFanout, i )
             Abc_ObjAddFanin( pClone, pFanout );
@@ -480,26 +661,24 @@ printf( "Adding buffer\n" );
         Abc_BufUpdateDep( p, pClone );
         Abc_BufAddToQue( p, pObj );
         Abc_BufAddToQue( p, pClone );
+        Abc_ObjForEachFanin( pObj, pFanout, i )
+            Abc_BufAddToQue( p, pFanout );
         p->nDuplicate++;
-        // add fanins to queue
 if ( fVerbose )
 printf( "Duplicating node\n" );
     }
-
-    else if ( Abc_ObjFanoutNum(pObj) >= 12 )
+    else if ( (nCrit > 0 && Abc_ObjFanoutNum(pObj) > 8) || Abc_ObjFanoutNum(pObj) > p->nFanMax )
     {
-        // branch (consider buffer)
-//        int nFan     = Abc_ObjFanoutNum(pObj);
-        int nFan     = 64;
-        double Res   = pow(nFan, 0.34);
-        int Temp     = (int)pow(Abc_ObjFanoutNum(pObj), 0.34);
-        int nDegree  = Abc_MinInt( 4, (int)pow(Abc_ObjFanoutNum(pObj), 0.34) );
-        int n1Degree = Abc_ObjFanoutNum(pObj) / nDegree + 1;
-        int n1Number = Abc_ObjFanoutNum(pObj) % nDegree;
-        int nFirst   = n1Degree * n1Number;
-//        Abc_Obj_t * pNonBuff = Abc_BufFindNonBuffDriver( p, pObj );
-        // create inverters
+        // (2) only critical or only non-critical - add buffer/inverter tree
+        int nDegree, n1Degree, n1Number, nFirst;
         int iFirstBuf = Abc_NtkObjNumMax( p->pNtk );
+//        nDegree  = Abc_MinInt( 3, (int)pow(Abc_ObjFanoutNum(pObj), 0.34) );
+        nDegree  = Abc_MinInt( 10, (int)pow(Abc_ObjFanoutNum(pObj), 0.5) );
+        n1Degree = Abc_ObjFanoutNum(pObj) / nDegree + 1;
+        n1Number = Abc_ObjFanoutNum(pObj) % nDegree;
+        nFirst   = n1Degree * n1Number;
+        p->nBranchCrit += (nCrit > 0);
+        // create inverters
         Abc_NodeCollectFanouts( pObj, p->vFanouts );
         if ( Abc_ObjIsNode(pObj) && Abc_NodeIsBuf(pObj) )
         {
@@ -520,16 +699,13 @@ printf( "Adding %d inverters\n", nDegree );
 if ( fVerbose )
 printf( "Adding %d buffers\n", nDegree );
         }
-        // create inverters
+        // connect inverters
         Vec_PtrForEachEntry( Abc_Obj_t *, p->vFanouts, pFanout, i )
         {
             j = (i < nFirst) ? i/n1Degree : n1Number + ((i - nFirst)/(n1Degree - 1));
             assert( j >= 0 && j < nDegree );
             Abc_ObjPatchFanin( pFanout, pObj, Abc_NtkObj(p->pNtk, iFirstBuf + j) );
         }
-        // remove node
-//        if ( Abc_ObjIsNode(pObj) && Abc_ObjFanoutNum(pObj) == 0 )
-//            Abc_NtkDeleteObj_rec( pObj, 1 );
         // update timing
         for ( i = 0; i < nDegree; i++ )
             Abc_BufCreateEdges( p, Abc_NtkObj(p->pNtk, iFirstBuf + i) );
@@ -548,19 +724,18 @@ printf( "Doing nothing\n" );
 //    if ( DelayMax != p->DelayMax )
 //        printf( "%d (%.2f)  ", p->DelayMax, 1.0 * p->DelayMax * p->DelayInv / BUF_SCALE );
 }
-Abc_Ntk_t * Abc_SclBufPerform( Abc_Ntk_t * pNtk, int fVerbose )
+Abc_Ntk_t * Abc_SclBufPerform( Abc_Ntk_t * pNtk, int FanMin, int FanMax, int fVerbose )
 {
     Abc_Ntk_t * pNew;
-    Buf_Man_t * p = Buf_ManStart( pNtk );
+    Buf_Man_t * p = Buf_ManStart( pNtk, FanMin, FanMax );
     int i, Limit = ABC_INFINITY;
-//    int i, Limit = 3;
     for ( i = 0; i < Limit && Vec_QueSize(p->vQue); i++ )
         Abc_BufPerformOne( p, Vec_QuePop(p->vQue), fVerbose );
     Buf_ManStop( p );
-    // duplication in topo order
+//    Abc_BufReplaceBufsByInvs( pNtk );
+    // duplicate network in topo order
     pNew = Abc_NtkDupDfs( pNtk );
     Abc_SclCheckNtk( pNew, fVerbose );
-//    Abc_NtkDelete( pNew );
     return pNew;
 }
 
diff --git a/src/map/scl/sclLib.c b/src/map/scl/sclLib.c
index 3e6f330f..a1572095 100644
--- a/src/map/scl/sclLib.c
+++ b/src/map/scl/sclLib.c
@@ -711,14 +711,16 @@ void Abc_SclHashCells( SC_Lib * p )
 }
 int Abc_SclCellFind( SC_Lib * p, char * pName )
 {
-    return *Abc_SclHashLookup( p, pName );
+    int *pPlace = Abc_SclHashLookup( p, pName );
+    return pPlace ? *pPlace : -1;
 }
 int Abc_SclClassCellNum( SC_Cell * pClass )
 {
     SC_Cell * pCell;
     int i, Count = 0;
     SC_RingForEachCell( pClass, pCell, i )
-        Count++;
+        if ( !pCell->fSkip )
+            Count++;
     return Count;
 }
 
@@ -955,14 +957,15 @@ float Abc_SclComputeDelayClassPin( SC_Lib * p, SC_Cell * pRepr, int iPin, float
     float Delay = 0;
     int i, Count = 0;
     SC_RingForEachCell( pRepr, pCell, i )
-        Count++;
-    SC_RingForEachCell( pRepr, pCell, i )
     {
-        if ( pRepr == pCell && Count > 1 ) // skip the first gate
+        if ( pCell->fSkip ) 
             continue;
+//        if ( pRepr == pCell ) // skip the first gate
+//            continue;
         Delay += Abc_SclComputeDelayCellPin( p, pCell, iPin, Slew, Gain );
+        Count++;
     }
-    return Delay / Abc_MaxInt(1, Count-1);
+    return Delay / Abc_MaxInt(1, Count);
 }
 float Abc_SclComputeAreaClass( SC_Cell * pRepr )
 {
@@ -971,6 +974,8 @@ float Abc_SclComputeAreaClass( SC_Cell * pRepr )
     int i, Count = 0;
     SC_RingForEachCell( pRepr, pCell, i )
     {
+        if ( pCell->fSkip ) 
+            continue;
         Area += pCell->area;
         Count++;
     }
@@ -988,6 +993,35 @@ float Abc_SclComputeAreaClass( SC_Cell * pRepr )
   SeeAlso     []
 
 ***********************************************************************/
+void Abc_SclMarkSkippedCells( SC_Lib * p )
+{
+    char FileName[1000];
+    char Buffer[1000], * pName;
+    SC_Cell * pCell;
+    FILE * pFile;
+    int CellId, nSkipped = 0;
+    sprintf( FileName, "%s.skip", p->pName );
+    pFile = fopen( FileName, "rb" );
+    if ( pFile == NULL )
+        return;
+    while ( fgets( Buffer, 999, pFile ) != NULL )
+    {
+        pName = strtok( Buffer, "\r\n\t " );
+        if ( pName == NULL )
+            continue;
+        CellId = Abc_SclCellFind( p, pName );
+        if ( CellId == -1 )
+        {
+            printf( "Cannot find cell \"%s\" in the library \"%s\".\n", pName, p->pName );
+            continue;
+        }
+        pCell = SC_LibCell( p, CellId );
+        pCell->fSkip = 1;
+        nSkipped++;
+    }
+    fclose( pFile );
+    printf( "Marked %d cells for skipping in the library \"%s\".\n", nSkipped, p->pName );
+}
 void Abc_SclPrintCells( SC_Lib * p, float Slew, float Gain )
 {
     SC_Cell * pCell, * pRepr;
@@ -998,6 +1032,7 @@ void Abc_SclPrintCells( SC_Lib * p, float Slew, float Gain )
     printf( "has %d cells in %d classes.  ", 
         Vec_PtrSize(p->vCells), Vec_PtrSize(p->vCellClasses) );
     printf( "Delay estimate is based on slew %.2f and gain %.2f.\n", Slew, Gain );
+    Abc_SclMarkSkippedCells( p );
     // find the longest name
     SC_LibForEachCellClass( p, pRepr, k )
         SC_RingForEachCell( pRepr, pCell, i )
@@ -1017,7 +1052,9 @@ void Abc_SclPrintCells( SC_Lib * p, float Slew, float Gain )
         SC_RingForEachCell( pRepr, pCell, i )
         {
             Abc_SclComputeParametersCell( p, pCell, Slew, &ED, &PD );
-            printf( "  %3d : ",       i+1 );
+            printf( "  %3d ",         i+1 );
+            printf( "%s",             pCell->fSkip ? "s" : " " );
+            printf( " : " );
             printf( "%-*s  ",         nLength, pCell->pName );
             printf( "%2d   ",         pCell->drive_strength );
             printf( "A =%8.2f   ",    pCell->area );
@@ -1027,7 +1064,7 @@ void Abc_SclPrintCells( SC_Lib * p, float Slew, float Gain )
             printf( "C =%5.1f ff   ", Abc_SclGatePinCapAve(p, pCell) );
             printf( "Lm =%5.1f ff  ", 0.01 * Gain * Abc_SclGatePinCapAve(p, pCell) );
 //            printf( "MaxS =%5.1f ps  ",   SC_CellPin(pCell, pCell->n_inputs)->max_out_slew );
-            printf( "Lm2 =%5.0f ff",  SC_CellPin(pCell, pCell->n_inputs)->max_out_cap );
+            printf( "Lm2 =%5.0f ff ",  SC_CellPin(pCell, pCell->n_inputs)->max_out_cap );
             printf( "\n" );
         }
     }
@@ -1052,6 +1089,7 @@ Vec_Str_t * Abc_SclDeriveGenlibStr( SC_Lib * p, float Slew, float Gain, int nGat
     SC_Cell * pRepr;
     SC_Pin * pPin;
     int i, k, Count = 2;
+    Abc_SclMarkSkippedCells( p );
     vStr = Vec_StrAlloc( 1000 );
     Vec_StrPrintStr( vStr, "GATE _const0_            0.00 z=CONST0;\n" );
     Vec_StrPrintStr( vStr, "GATE _const1_            0.00 z=CONST1;\n" );
@@ -1078,6 +1116,7 @@ Vec_Str_t * Abc_SclDeriveGenlibStr( SC_Lib * p, float Slew, float Gain, int nGat
         SC_CellForEachPinIn( pRepr, pPin, k )
         {
             float Delay = Abc_SclComputeDelayClassPin( p, pRepr, k, Slew, Gain );
+            assert( Delay > 0 );
             Vec_StrPrintStr( vStr, "         PIN " );
             sprintf( Buffer, "%-4s", pPin->pName );
             Vec_StrPrintStr( vStr, Buffer );
diff --git a/src/map/scl/sclLib.h b/src/map/scl/sclLib.h
index a087f124..08433f8f 100644
--- a/src/map/scl/sclLib.h
+++ b/src/map/scl/sclLib.h
@@ -166,6 +166,7 @@ struct SC_Cell_
 {
     char *         pName;
     int            Id;
+    int            fSkip;          // skip this cell during genlib computation
     int            seq;            // -- set to TRUE by parser if a sequential element
     int            unsupp;         // -- set to TRUE by parser if cell contains information we cannot handle
     float          area;
diff --git a/src/map/scl/sclSize.h b/src/map/scl/sclSize.h
index 0dad7ddb..f8d5fcbe 100644
--- a/src/map/scl/sclSize.h
+++ b/src/map/scl/sclSize.h
@@ -358,25 +358,37 @@ static inline SC_Cell * Abc_SclObjResiable( SC_Man * p, Abc_Obj_t * pObj, int fU
 ***********************************************************************/
 static inline void Abc_SclDumpStats( SC_Man * p, char * pFileName, abctime Time )
 {
+    static char FileNameOld[1000] = {0};
+    static int nNodesOld, nAreaOld, nDelayOld;
     FILE * pTable;
     pTable = fopen( pFileName, "a+" );
-    fprintf( pTable, "%s ", p->pNtk->pName );
-    fprintf( pTable, "%d ", Abc_NtkPiNum(p->pNtk) );
-    fprintf( pTable, "%d ", Abc_NtkPoNum(p->pNtk) );
-    fprintf( pTable, "%d ", Abc_NtkNodeNum(p->pNtk) );
-    fprintf( pTable, "%d ", (int)p->SumArea );
-    fprintf( pTable, "%d ", (int)p->ReportDelay );
-//    fprintf( pTable, "%.2f ", 1.0*Time/CLOCKS_PER_SEC );
-    fprintf( pTable, "\n" );
+    if ( strcmp( FileNameOld, p->pNtk->pName ) )
+    {
+        sprintf( FileNameOld, "%s", p->pNtk->pName );
+        fprintf( pTable, "\n" );
+        fprintf( pTable, "%s ", p->pNtk->pName );
+        fprintf( pTable, "%d ", Abc_NtkPiNum(p->pNtk) );
+        fprintf( pTable, "%d ", Abc_NtkPoNum(p->pNtk) );
+        fprintf( pTable, "%d ", (nNodesOld = Abc_NtkNodeNum(p->pNtk)) );
+        fprintf( pTable, "%d ", (nAreaOld  = (int)p->SumArea)         );
+        fprintf( pTable, "%d ", (nDelayOld = (int)p->ReportDelay)     );
+    }
+    else
+    {
+        fprintf( pTable, " " );
+        fprintf( pTable, "%.1f ", 100.0 * Abc_NtkNodeNum(p->pNtk) / nNodesOld );
+        fprintf( pTable, "%.1f ", 100.0 * (int)p->SumArea         / nAreaOld  );
+        fprintf( pTable, "%.1f ", 100.0 * (int)p->ReportDelay     / nDelayOld );
+    }
+    //    fprintf( pTable, "%.2f ", 1.0*Time/CLOCKS_PER_SEC );
     fclose( pTable );
 }
 
 
-/*=== sclBuff.c ===============================================================*/
+/*=== sclBuffer.c ===============================================================*/
 extern int           Abc_SclCheckNtk( Abc_Ntk_t * p, int fVerbose );
 extern Abc_Ntk_t *   Abc_SclPerformBuffering( Abc_Ntk_t * p, int Degree, int fUseInvs, int fVerbose );
-/*=== sclBuffer.c ===============================================================*/
-extern Abc_Ntk_t *   Abc_SclBufPerform( Abc_Ntk_t * pNtk, int fVerbose );
+extern Abc_Ntk_t *   Abc_SclBufPerform( Abc_Ntk_t * pNtk, int FanMin, int FanMax, int fVerbose );
 /*=== sclDnsize.c ===============================================================*/
 extern void          Abc_SclDnsizePerform( SC_Lib * pLib, Abc_Ntk_t * pNtk, SC_SizePars * pPars );
 /*=== sclLoad.c ===============================================================*/