Version abc80130_2

1 files changed, 1593 insertions, 0 deletions

diff --git a/src/aig/ivy/ivyFastMap.c b/src/aig/ivy/ivyFastMap.c
new file mode 100644
index 00000000..c4a043f2
--- /dev/null
+++ b/src/aig/ivy/ivyFastMap.c
@@ -0,0 +1,1593 @@
+/**CFile****************************************************************
+
+  FileName    [ivyFastMap.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [And-Inverter Graph package.]
+
+  Synopsis    [Fast FPGA mapping.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - May 11, 2006.]
+
+  Revision    [$Id: ivyFastMap.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "ivy.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+#define IVY_INFINITY   10000
+
+typedef struct Ivy_SuppMan_t_ Ivy_SuppMan_t;
+struct Ivy_SuppMan_t_ 
+{
+    int         nLimit;    // the limit on the number of inputs
+    int         nObjs;     // the number of entries
+    int         nSize;     // size of each entry in bytes
+    char *      pMem;      // memory allocated
+    Vec_Vec_t * vLuts;     // the array of nodes used in the mapping
+};
+
+typedef struct Ivy_Supp_t_ Ivy_Supp_t;
+struct Ivy_Supp_t_ 
+{
+    char        nSize;     // the number of support nodes
+    char        fMark;     // multipurpose mask
+    char        fMark2;    // multipurpose mask 
+    char        fMark3;    // multipurpose mask 
+    int         nRefs;     // the number of references
+    short       Delay;     // the delay of the node
+    short       DelayR;    // the reverse delay of the node
+    int         pArray[0]; // the support nodes
+};
+
+static inline Ivy_Supp_t * Ivy_ObjSupp( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )      
+{ 
+    return (Ivy_Supp_t *)(((Ivy_SuppMan_t*)pAig->pData)->pMem + pObj->Id * ((Ivy_SuppMan_t*)pAig->pData)->nSize); 
+}
+static inline Ivy_Supp_t * Ivy_ObjSuppStart( Ivy_Man_t * pAig, Ivy_Obj_t * pObj ) 
+{ 
+    Ivy_Supp_t * pSupp;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    pSupp->fMark = 0;
+    pSupp->Delay = 0;
+    pSupp->nSize = 1;
+    pSupp->pArray[0] = pObj->Id;
+    return pSupp;
+}
+
+static void Ivy_FastMapPrint( Ivy_Man_t * pAig, int Delay, int Area, int Time, char * pStr );
+static int  Ivy_FastMapDelay( Ivy_Man_t * pAig );
+static int  Ivy_FastMapArea( Ivy_Man_t * pAig );
+static void Ivy_FastMapNode( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit );
+static void Ivy_FastMapNodeArea( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit );
+static int  Ivy_FastMapMerge( Ivy_Supp_t * pSupp0, Ivy_Supp_t * pSupp1, Ivy_Supp_t * pSupp, int nLimit );
+static void Ivy_FastMapRequired( Ivy_Man_t * pAig, int Delay, int fSetInter );
+static void Ivy_FastMapRecover( Ivy_Man_t * pAig, int nLimit );
+static int  Ivy_FastMapNodeDelay( Ivy_Man_t * pAig, Ivy_Obj_t * pObj );
+static int  Ivy_FastMapNodeAreaRefed( Ivy_Man_t * pAig, Ivy_Obj_t * pObj );
+static int  Ivy_FastMapNodeAreaDerefed( Ivy_Man_t * pAig, Ivy_Obj_t * pObj );
+static void Ivy_FastMapNodeRecover( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront, Vec_Ptr_t * vFrontOld );
+static int  Ivy_FastMapNodeRef( Ivy_Man_t * pAig, Ivy_Obj_t * pObj );
+static int  Ivy_FastMapNodeDeref( Ivy_Man_t * pAig, Ivy_Obj_t * pObj );
+
+
+extern int s_MappingTime;
+extern int s_MappingMem;
+
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast K-LUT mapping of the AIG.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapPerform( Ivy_Man_t * pAig, int nLimit, int fRecovery, int fVerbose )
+{
+    Ivy_SuppMan_t * pMan;
+    Ivy_Obj_t * pObj;
+    int i, Delay, Area, clk, clkTotal = clock();
+    // start the memory for supports
+    pMan = ALLOC( Ivy_SuppMan_t, 1 );
+    memset( pMan, 0, sizeof(Ivy_SuppMan_t) );
+    pMan->nLimit = nLimit;
+    pMan->nObjs  = Ivy_ManObjIdMax(pAig) + 1;
+    pMan->nSize  = sizeof(Ivy_Supp_t) + nLimit * sizeof(int);
+    pMan->pMem   = (char *)malloc( pMan->nObjs * pMan->nSize );
+    memset( pMan->pMem, 0, pMan->nObjs * pMan->nSize );
+    pMan->vLuts  = Vec_VecAlloc( 100 );
+    pAig->pData  = pMan;
+clk = clock();
+    // set the PI mapping
+    Ivy_ObjSuppStart( pAig, Ivy_ManConst1(pAig) );
+    Ivy_ManForEachPi( pAig, pObj, i )
+        Ivy_ObjSuppStart( pAig, pObj );
+    // iterate through all nodes in the topological order
+    Ivy_ManForEachNode( pAig, pObj, i )
+        Ivy_FastMapNode( pAig, pObj, nLimit );
+    // find the best arrival time and area
+    Delay = Ivy_FastMapDelay( pAig );
+    Area = Ivy_FastMapArea(pAig);
+    if ( fVerbose )
+        Ivy_FastMapPrint( pAig, Delay, Area, clock() - clk, "Delay oriented mapping: " );
+
+// 2-1-2 (doing 2-1-2-1-2 improves 0.5%)
+
+    if ( fRecovery )
+    {
+clk = clock();
+    Ivy_FastMapRequired( pAig, Delay, 0 );
+    // remap the nodes
+    Ivy_FastMapRecover( pAig, nLimit );
+    Delay = Ivy_FastMapDelay( pAig );
+    Area = Ivy_FastMapArea(pAig);
+    if ( fVerbose )
+        Ivy_FastMapPrint( pAig, Delay, Area, clock() - clk, "Area recovery 2       : " );
+
+clk = clock();
+    Ivy_FastMapRequired( pAig, Delay, 0 );
+    // iterate through all nodes in the topological order
+    Ivy_ManForEachNode( pAig, pObj, i )
+        Ivy_FastMapNodeArea( pAig, pObj, nLimit );
+    Delay = Ivy_FastMapDelay( pAig );
+    Area = Ivy_FastMapArea(pAig);
+    if ( fVerbose )
+        Ivy_FastMapPrint( pAig, Delay, Area, clock() - clk, "Area recovery 1       : " );
+
+clk = clock();
+    Ivy_FastMapRequired( pAig, Delay, 0 );
+    // remap the nodes
+    Ivy_FastMapRecover( pAig, nLimit );
+    Delay = Ivy_FastMapDelay( pAig );
+    Area = Ivy_FastMapArea(pAig);
+    if ( fVerbose )
+        Ivy_FastMapPrint( pAig, Delay, Area, clock() - clk, "Area recovery 2       : " );
+    }
+
+
+    s_MappingTime = clock() - clkTotal;
+    s_MappingMem = pMan->nObjs * pMan->nSize;
+/*
+    {
+        Vec_Ptr_t * vNodes;
+        vNodes = Vec_PtrAlloc( 100 );
+        Vec_VecForEachEntry( pMan->vLuts, pObj, i, k )
+            Vec_PtrPush( vNodes, pObj );
+        Ivy_ManShow( pAig, 0, vNodes );
+        Vec_PtrFree( vNodes );
+    }
+*/
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Cleans memory used for decomposition.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapStop( Ivy_Man_t * pAig )
+{
+    Ivy_SuppMan_t * p = pAig->pData;
+    Vec_VecFree( p->vLuts );
+    free( p->pMem );
+    free( p );
+    pAig->pData = NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prints statistics.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapPrint( Ivy_Man_t * pAig, int Delay, int Area, int Time, char * pStr )
+{
+    printf( "%s : Delay = %3d. Area = %6d. ", pStr, Delay, Area );
+    PRT( "Time", Time );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes delay after LUT mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapDelay( Ivy_Man_t * pAig )
+{
+    Ivy_Supp_t * pSupp;
+    Ivy_Obj_t * pObj;
+    int i, DelayMax = 0;
+    Ivy_ManForEachPo( pAig, pObj, i )
+    {
+        pObj = Ivy_ObjFanin0(pObj);
+        if ( !Ivy_ObjIsNode(pObj) )
+            continue;
+        pSupp = Ivy_ObjSupp( pAig, pObj );
+        if ( DelayMax < pSupp->Delay )
+            DelayMax = pSupp->Delay;
+    }
+    return DelayMax;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes area after mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapArea_rec( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, Vec_Vec_t * vLuts )
+{
+    Ivy_Supp_t * pSupp;
+    int i, Counter;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    // skip visited nodes and PIs
+    if ( pSupp->fMark || pSupp->nSize == 1 )
+        return 0;
+    pSupp->fMark = 1;
+    // compute the area of this node
+    Counter = 0;
+    for ( i = 0; i < pSupp->nSize; i++ )
+        Counter += Ivy_FastMapArea_rec( pAig, Ivy_ManObj(pAig, pSupp->pArray[i]), vLuts );
+    // add the node to the array of LUTs
+    Vec_VecPush( vLuts, pSupp->Delay, pObj );
+    return 1 + Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes area after mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapArea( Ivy_Man_t * pAig )
+{
+    Vec_Vec_t * vLuts;
+    Ivy_Obj_t * pObj;
+    int i, Counter = 0;
+    // get the array to store the nodes
+    vLuts = ((Ivy_SuppMan_t *)pAig->pData)->vLuts;
+    Vec_VecClear( vLuts );
+    // explore starting from each node
+    Ivy_ManForEachPo( pAig, pObj, i )
+        Counter += Ivy_FastMapArea_rec( pAig, Ivy_ObjFanin0(pObj), vLuts );
+    // clean the marks
+    Ivy_ManForEachNode( pAig, pObj, i )
+        Ivy_ObjSupp( pAig, pObj )->fMark = 0;
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline Ivy_ObjIsNodeInt1( Ivy_Obj_t * pObj )
+{
+    return Ivy_ObjIsNode(pObj) && Ivy_ObjRefs(pObj) == 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline Ivy_ObjIsNodeInt2( Ivy_Obj_t * pObj )
+{
+    return Ivy_ObjIsNode(pObj) && Ivy_ObjRefs(pObj) <= 2;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline void Vec_IntSelectSort( int * pArray, int nSize )
+{
+    int temp, i, j, best_i;
+    for ( i = 0; i < nSize-1; i++ )
+    {
+        best_i = i;
+        for ( j = i+1; j < nSize; j++ )
+            if ( pArray[j] < pArray[best_i] )
+                best_i = j;
+        temp = pArray[i]; 
+        pArray[i] = pArray[best_i]; 
+        pArray[best_i] = temp;
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline int Vec_IntRemoveDup( int * pArray, int nSize )
+{
+    int i, k;
+    if ( nSize < 2 )
+        return nSize;
+    for ( i = k = 1; i < nSize; i++ )
+        if ( pArray[i] != pArray[i-1] )
+            pArray[k++] = pArray[i];
+    return k;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeArea2( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit )
+{
+    static int Store[32], StoreSize;
+    static char Supp0[16], Supp1[16];
+    static Ivy_Supp_t * pTemp0 = (Ivy_Supp_t *)Supp0;
+    static Ivy_Supp_t * pTemp1 = (Ivy_Supp_t *)Supp1;
+    Ivy_Obj_t * pFanin0, * pFanin1;
+    Ivy_Supp_t * pSupp0, * pSupp1, * pSupp;
+    int RetValue, DelayOld;
+    assert( nLimit <= 32 );
+    assert( Ivy_ObjIsNode(pObj) );
+    // get the fanins
+    pFanin0 = Ivy_ObjFanin0(pObj);
+    pFanin1 = Ivy_ObjFanin1(pObj);
+    // get the supports
+    pSupp0 = Ivy_ObjSupp( pAig, pFanin0 );
+    pSupp1 = Ivy_ObjSupp( pAig, pFanin1 );
+    pSupp  = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->fMark == 0 );
+    // get the old delay of the node
+    DelayOld = Ivy_FastMapNodeDelay(pAig, pObj);
+    assert( DelayOld <= pSupp->DelayR );
+    // copy the current cut
+    memcpy( Store, pSupp->pArray, sizeof(int) * pSupp->nSize );
+    StoreSize = pSupp->nSize;
+    // get the fanin support
+    if ( Ivy_ObjRefs(pFanin0) > 1 && pSupp0->Delay < pSupp->DelayR )
+    {
+        pSupp0 = pTemp0;
+        pSupp0->nSize = 1;
+        pSupp0->pArray[0] = Ivy_ObjFaninId0(pObj);
+    }
+    // get the fanin support
+    if ( Ivy_ObjRefs(pFanin1) > 1 && pSupp1->Delay < pSupp->DelayR )
+    {
+        pSupp1 = pTemp1;
+        pSupp1->nSize = 1;
+        pSupp1->pArray[0] = Ivy_ObjFaninId1(pObj);
+    }
+    // merge the cuts
+    if ( pSupp0->nSize < pSupp1->nSize )
+        RetValue = Ivy_FastMapMerge( pSupp1, pSupp0, pSupp, nLimit );
+    else
+        RetValue = Ivy_FastMapMerge( pSupp0, pSupp1, pSupp, nLimit );
+    if ( !RetValue )
+    {
+        pSupp->nSize = 2;
+        pSupp->pArray[0] = Ivy_ObjFaninId0(pObj);
+        pSupp->pArray[1] = Ivy_ObjFaninId1(pObj);
+    }
+    // check the resulting delay
+    pSupp->Delay = Ivy_FastMapNodeDelay(pAig, pObj);
+    if ( pSupp->Delay > pSupp->DelayR )
+    {
+        pSupp->nSize = StoreSize;
+        memcpy( pSupp->pArray, Store, sizeof(int) * pSupp->nSize );
+        pSupp->Delay = DelayOld;
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeArea( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit )
+{
+    static int Store[32], StoreSize;
+    static char Supp0[16], Supp1[16];
+    static Ivy_Supp_t * pTemp0 = (Ivy_Supp_t *)Supp0;
+    static Ivy_Supp_t * pTemp1 = (Ivy_Supp_t *)Supp1;
+    Ivy_Obj_t * pFanin0, * pFanin1;
+    Ivy_Supp_t * pSupp0, * pSupp1, * pSupp;
+    int RetValue, DelayOld, RefsOld;
+    int AreaBef, AreaAft;
+    assert( nLimit <= 32 );
+    assert( Ivy_ObjIsNode(pObj) );
+    // get the fanins
+    pFanin0 = Ivy_ObjFanin0(pObj);
+    pFanin1 = Ivy_ObjFanin1(pObj);
+    // get the supports
+    pSupp0 = Ivy_ObjSupp( pAig, pFanin0 );
+    pSupp1 = Ivy_ObjSupp( pAig, pFanin1 );
+    pSupp  = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->fMark == 0 );
+
+    // get the area
+    if ( pSupp->nRefs == 0 )
+        AreaBef = Ivy_FastMapNodeAreaDerefed( pAig, pObj );
+    else
+        AreaBef = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+//    if ( AreaBef == 1 )
+//        return;
+
+    // deref the cut if the node is refed
+    if ( pSupp->nRefs != 0 )
+        Ivy_FastMapNodeDeref( pAig, pObj );
+
+    // get the old delay of the node
+    DelayOld = Ivy_FastMapNodeDelay(pAig, pObj);
+    assert( DelayOld <= pSupp->DelayR );
+    // copy the current cut
+    memcpy( Store, pSupp->pArray, sizeof(int) * pSupp->nSize );
+    StoreSize = pSupp->nSize;
+    // get the fanin support
+    if ( Ivy_ObjRefs(pFanin0) > 2 && pSupp0->Delay < pSupp->DelayR )
+//    if ( pSupp0->nRefs > 0 && pSupp0->Delay < pSupp->DelayR ) // this leads to 2% worse results
+    {
+        pSupp0 = pTemp0;
+        pSupp0->nSize = 1;
+        pSupp0->pArray[0] = Ivy_ObjFaninId0(pObj);
+    }
+    // get the fanin support
+    if ( Ivy_ObjRefs(pFanin1) > 2 && pSupp1->Delay < pSupp->DelayR )
+//    if ( pSupp1->nRefs > 0 && pSupp1->Delay < pSupp->DelayR )
+    {
+        pSupp1 = pTemp1;
+        pSupp1->nSize = 1;
+        pSupp1->pArray[0] = Ivy_ObjFaninId1(pObj);
+    }
+    // merge the cuts
+    if ( pSupp0->nSize < pSupp1->nSize )
+        RetValue = Ivy_FastMapMerge( pSupp1, pSupp0, pSupp, nLimit );
+    else
+        RetValue = Ivy_FastMapMerge( pSupp0, pSupp1, pSupp, nLimit );
+    if ( !RetValue )
+    {
+        pSupp->nSize = 2;
+        pSupp->pArray[0] = Ivy_ObjFaninId0(pObj);
+        pSupp->pArray[1] = Ivy_ObjFaninId1(pObj);
+    }
+
+    // check the resulting delay
+    pSupp->Delay = Ivy_FastMapNodeDelay(pAig, pObj);
+
+    RefsOld = pSupp->nRefs; pSupp->nRefs = 0;
+    AreaAft = Ivy_FastMapNodeAreaDerefed( pAig, pObj );
+    pSupp->nRefs = RefsOld;
+
+    if ( AreaAft > AreaBef || pSupp->Delay > pSupp->DelayR )
+//    if ( pSupp->Delay > pSupp->DelayR )
+    {
+        pSupp->nSize = StoreSize;
+        memcpy( pSupp->pArray, Store, sizeof(int) * pSupp->nSize );
+        pSupp->Delay = DelayOld;
+//        printf( "-" );
+    }
+//    else
+//        printf( "+" );
+
+    if ( pSupp->nRefs != 0 )
+        Ivy_FastMapNodeRef( pAig, pObj );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs fast mapping for one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNode( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit )
+{
+    Ivy_Supp_t * pSupp0, * pSupp1, * pSupp;
+    int fFaninParam = 2;
+    int RetValue;
+    assert( Ivy_ObjIsNode(pObj) );
+    // get the supports
+    pSupp0 = Ivy_ObjSupp( pAig, Ivy_ObjFanin0(pObj) );
+    pSupp1 = Ivy_ObjSupp( pAig, Ivy_ObjFanin1(pObj) );
+    pSupp  = Ivy_ObjSupp( pAig, pObj );
+    pSupp->fMark = 0;
+    // get the delays
+    if ( pSupp0->Delay == pSupp1->Delay )
+        pSupp->Delay = (pSupp0->Delay == 0) ? pSupp0->Delay + 1: pSupp0->Delay;
+    else if ( pSupp0->Delay > pSupp1->Delay )
+    {
+        pSupp->Delay = pSupp0->Delay;
+        pSupp1 = Ivy_ObjSupp( pAig, Ivy_ManConst1(pAig) );
+        pSupp1->pArray[0] = Ivy_ObjFaninId1(pObj);
+    }
+    else // if ( pSupp0->Delay < pSupp1->Delay )
+    {
+        pSupp->Delay = pSupp1->Delay;
+        pSupp0 = Ivy_ObjSupp( pAig, Ivy_ManConst1(pAig) );
+        pSupp0->pArray[0] = Ivy_ObjFaninId0(pObj);
+    }
+    // merge the cuts
+    if ( pSupp0->nSize < pSupp1->nSize )
+        RetValue = Ivy_FastMapMerge( pSupp1, pSupp0, pSupp, nLimit );
+    else
+        RetValue = Ivy_FastMapMerge( pSupp0, pSupp1, pSupp, nLimit );
+    if ( !RetValue )
+    {
+        pSupp->Delay++;
+        if ( fFaninParam == 2 )
+        {
+            pSupp->nSize = 2;
+            pSupp->pArray[0] = Ivy_ObjFaninId0(pObj);
+            pSupp->pArray[1] = Ivy_ObjFaninId1(pObj);
+        }
+        else if ( fFaninParam == 3 )
+        {
+            Ivy_Obj_t * pFanin0, * pFanin1, * pFaninA, * pFaninB;
+            pFanin0 = Ivy_ObjFanin0(pObj);
+            pFanin1 = Ivy_ObjFanin1(pObj);
+            pSupp->nSize = 0;
+            // process the first fanin
+            if ( Ivy_ObjIsNodeInt1(pFanin0) )
+            {
+                pFaninA = Ivy_ObjFanin0(pFanin0);
+                pFaninB = Ivy_ObjFanin1(pFanin0);
+                if ( Ivy_ObjIsNodeInt1(pFaninA) && Ivy_ObjIsNodeInt1(pFaninB) )
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin0);
+                else
+                {
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninA);
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninB);
+                }
+            }
+            else
+                pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin0);
+            // process the second fanin
+            if ( Ivy_ObjIsNodeInt1(pFanin1) )
+            {
+                pFaninA = Ivy_ObjFanin0(pFanin1);
+                pFaninB = Ivy_ObjFanin1(pFanin1);
+                if ( Ivy_ObjIsNodeInt1(pFaninA) && Ivy_ObjIsNodeInt1(pFaninB) )
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin1);
+                else
+                {
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninA);
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninB);
+                }
+            }
+            else
+                pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin1);
+            // sort the fanins
+            Vec_IntSelectSort( pSupp->pArray, pSupp->nSize );
+            pSupp->nSize = Vec_IntRemoveDup( pSupp->pArray, pSupp->nSize );
+            assert( pSupp->pArray[0] < pSupp->pArray[1] );
+        }
+        else if ( fFaninParam == 4 )
+        {
+            Ivy_Obj_t * pFanin0, * pFanin1, * pFaninA, * pFaninB;
+            pFanin0 = Ivy_ObjFanin0(pObj);
+            pFanin1 = Ivy_ObjFanin1(pObj);
+            pSupp->nSize = 0;
+            // consider the case when exactly one of them is internal
+            if ( Ivy_ObjIsNodeInt1(pFanin0) ^ Ivy_ObjIsNodeInt1(pFanin1) )
+            {
+                pSupp0 = Ivy_ObjSupp( pAig, Ivy_ObjFanin0(pObj) );
+                pSupp1 = Ivy_ObjSupp( pAig, Ivy_ObjFanin1(pObj) );
+                if ( Ivy_ObjIsNodeInt1(pFanin0) && pSupp0->nSize < nLimit )
+                {
+                    pSupp->Delay = IVY_MAX( pSupp0->Delay, pSupp1->Delay + 1 );
+                    pSupp1 = Ivy_ObjSupp( pAig, Ivy_ManConst1(pAig) );
+                    pSupp1->pArray[0] = Ivy_ObjId(pFanin1);
+                    // merge the cuts
+                    RetValue = Ivy_FastMapMerge( pSupp0, pSupp1, pSupp, nLimit );
+                    assert( RetValue );
+                    assert( pSupp->nSize > 1 );
+                    return;
+                }
+                if ( Ivy_ObjIsNodeInt1(pFanin1) && pSupp1->nSize < nLimit )
+                {
+                    pSupp->Delay = IVY_MAX( pSupp1->Delay, pSupp0->Delay + 1 );
+                    pSupp0 = Ivy_ObjSupp( pAig, Ivy_ManConst1(pAig) );
+                    pSupp0->pArray[0] = Ivy_ObjId(pFanin0);
+                    // merge the cuts
+                    RetValue = Ivy_FastMapMerge( pSupp1, pSupp0, pSupp, nLimit );
+                    assert( RetValue );
+                    assert( pSupp->nSize > 1 );
+                    return;
+                }
+            }
+            // process the first fanin
+            if ( Ivy_ObjIsNodeInt1(pFanin0) )
+            {
+                pFaninA = Ivy_ObjFanin0(pFanin0);
+                pFaninB = Ivy_ObjFanin1(pFanin0);
+                if ( Ivy_ObjIsNodeInt1(pFaninA) && Ivy_ObjIsNodeInt1(pFaninB) )
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin0);
+                else
+                {
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninA);
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninB);
+                }
+            }
+            else
+                pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin0);
+            // process the second fanin
+            if ( Ivy_ObjIsNodeInt1(pFanin1) )
+            {
+                pFaninA = Ivy_ObjFanin0(pFanin1);
+                pFaninB = Ivy_ObjFanin1(pFanin1);
+                if ( Ivy_ObjIsNodeInt1(pFaninA) && Ivy_ObjIsNodeInt1(pFaninB) )
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin1);
+                else
+                {
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninA);
+                    pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFaninB);
+                }
+            }
+            else
+                pSupp->pArray[pSupp->nSize++] = Ivy_ObjId(pFanin1);
+            // sort the fanins
+            Vec_IntSelectSort( pSupp->pArray, pSupp->nSize );
+            pSupp->nSize = Vec_IntRemoveDup( pSupp->pArray, pSupp->nSize );
+            assert( pSupp->pArray[0] < pSupp->pArray[1] );
+            assert( pSupp->nSize > 1 );
+        }
+    }
+    assert( pSupp->Delay > 0 );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Merges two supports]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapMerge( Ivy_Supp_t * pSupp0, Ivy_Supp_t * pSupp1, Ivy_Supp_t * pSupp, int nLimit )
+{ 
+    int i, k, c;
+    assert( pSupp0->nSize >= pSupp1->nSize );
+    // the case of the largest cut sizes
+    if ( pSupp0->nSize == nLimit && pSupp1->nSize == nLimit )
+    {
+        for ( i = 0; i < pSupp0->nSize; i++ )
+            if ( pSupp0->pArray[i] != pSupp1->pArray[i] )
+                return 0;
+        for ( i = 0; i < pSupp0->nSize; i++ )
+            pSupp->pArray[i] = pSupp0->pArray[i];
+        pSupp->nSize = pSupp0->nSize;
+        return 1;
+    }
+    // the case when one of the cuts is the largest
+    if ( pSupp0->nSize == nLimit )
+    {
+        for ( i = 0; i < pSupp1->nSize; i++ )
+        {
+            for ( k = pSupp0->nSize - 1; k >= 0; k-- )
+                if ( pSupp0->pArray[k] == pSupp1->pArray[i] )
+                    break;
+            if ( k == -1 ) // did not find
+                return 0;
+        }
+        for ( i = 0; i < pSupp0->nSize; i++ )
+            pSupp->pArray[i] = pSupp0->pArray[i];
+        pSupp->nSize = pSupp0->nSize;
+        return 1;
+    }
+
+    // compare two cuts with different numbers
+    i = k = 0;
+    for ( c = 0; c < nLimit; c++ )
+    {
+        if ( k == pSupp1->nSize )
+        {
+            if ( i == pSupp0->nSize )
+            {
+                pSupp->nSize = c;
+                return 1;
+            }
+            pSupp->pArray[c] = pSupp0->pArray[i++];
+            continue;
+        }
+        if ( i == pSupp0->nSize )
+        {
+            if ( k == pSupp1->nSize )
+            {
+                pSupp->nSize = c;
+                return 1;
+            }
+            pSupp->pArray[c] = pSupp1->pArray[k++];
+            continue;
+        }
+        if ( pSupp0->pArray[i] < pSupp1->pArray[k] )
+        {
+            pSupp->pArray[c] = pSupp0->pArray[i++];
+            continue;
+        }
+        if ( pSupp0->pArray[i] > pSupp1->pArray[k] )
+        {
+            pSupp->pArray[c] = pSupp1->pArray[k++];
+            continue;
+        }
+        pSupp->pArray[c] = pSupp0->pArray[i++]; 
+        k++;
+    }
+    if ( i < pSupp0->nSize || k < pSupp1->nSize )
+        return 0;
+    pSupp->nSize = c;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates integer vector with the support of the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapReadSupp( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, Vec_Int_t * vLeaves )
+{
+    Ivy_Supp_t * pSupp;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    vLeaves->nCap   = 8;
+    vLeaves->nSize  = pSupp->nSize;
+    vLeaves->pArray = pSupp->pArray;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Sets the required times of the intermediate nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapRequired_rec( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, Ivy_Obj_t * pRoot, int DelayR )
+{
+    Ivy_Supp_t * pSupp;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    if ( pObj != pRoot && (pSupp->nRefs > 0 || Ivy_ObjIsCi(pObj)) )
+        return;
+    Ivy_FastMapRequired_rec( pAig, Ivy_ObjFanin0(pObj), pRoot, DelayR );
+    Ivy_FastMapRequired_rec( pAig, Ivy_ObjFanin1(pObj), pRoot, DelayR );
+//    assert( pObj == pRoot || pSupp->DelayR == IVY_INFINITY );
+    pSupp->DelayR = DelayR;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the required times for each node.]
+
+  Description [Sets reference counters for each node.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapRequired( Ivy_Man_t * pAig, int Delay, int fSetInter )
+{
+    Vec_Vec_t * vLuts;
+    Vec_Ptr_t * vNodes;
+    Ivy_Obj_t * pObj;
+    Ivy_Supp_t * pSupp, * pSuppF;
+    int i, k, c;
+    // clean the required times
+    Ivy_ManForEachPi( pAig, pObj, i )
+    {
+        pSupp = Ivy_ObjSupp( pAig, pObj );
+        pSupp->DelayR = IVY_INFINITY;
+        pSupp->nRefs = 0;
+    }
+    Ivy_ManForEachNode( pAig, pObj, i )
+    {
+        pSupp = Ivy_ObjSupp( pAig, pObj );
+        pSupp->DelayR = IVY_INFINITY;
+        pSupp->nRefs = 0;
+    }
+    // set the required times of the POs
+    Ivy_ManForEachPo( pAig, pObj, i )
+    {
+        pSupp = Ivy_ObjSupp( pAig, Ivy_ObjFanin0(pObj) );
+        pSupp->DelayR = Delay;
+        pSupp->nRefs++;
+    }
+    // get the levelized nodes used in the mapping
+    vLuts = ((Ivy_SuppMan_t *)pAig->pData)->vLuts;
+    // propagate the required times
+    Vec_VecForEachLevelReverse( vLuts, vNodes, i )
+    Vec_PtrForEachEntry( vNodes, pObj, k )
+    {
+        pSupp = Ivy_ObjSupp( pAig, pObj );
+        assert( pSupp->nRefs > 0 );
+        for ( c = 0; c < pSupp->nSize; c++ )
+        {
+            pSuppF = Ivy_ObjSupp( pAig, Ivy_ManObj(pAig, pSupp->pArray[c]) );
+            pSuppF->DelayR = IVY_MIN( pSuppF->DelayR, pSupp->DelayR - 1 );
+            pSuppF->nRefs++;
+        }
+    }
+/*
+    // print out some of the required times
+    Ivy_ManForEachPi( pAig, pObj, i )
+    {
+        pSupp = Ivy_ObjSupp( pAig, pObj );
+        printf( "%d ", pSupp->DelayR );
+    }
+    printf( "\n" );    
+*/
+
+    if ( fSetInter )
+    {
+        // set the required times of the intermediate nodes
+        Vec_VecForEachLevelReverse( vLuts, vNodes, i )
+        Vec_PtrForEachEntry( vNodes, pObj, k )
+        {
+            pSupp = Ivy_ObjSupp( pAig, pObj );
+            Ivy_FastMapRequired_rec( pAig, pObj, pObj, pSupp->DelayR ); 
+        }
+        // make sure that all required times are assigned
+        Ivy_ManForEachNode( pAig, pObj, i )
+        {
+            pSupp = Ivy_ObjSupp( pAig, pObj );
+            assert( pSupp->DelayR < IVY_INFINITY );
+        }
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs area recovery for each node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapRecover( Ivy_Man_t * pAig, int nLimit )
+{
+    Vec_Ptr_t * vFront, * vFrontOld;
+    Ivy_Obj_t * pObj;
+    int i;
+    vFront = Vec_PtrAlloc( nLimit );
+    vFrontOld = Vec_PtrAlloc( nLimit );
+    Ivy_ManCleanTravId( pAig );
+    // iterate through all nodes in the topological order
+    Ivy_ManForEachNode( pAig, pObj, i )
+        Ivy_FastMapNodeRecover( pAig, pObj, nLimit, vFront, vFrontOld );
+    Vec_PtrFree( vFrontOld );
+    Vec_PtrFree( vFront );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes the delay of the cut rooted at this node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeDelay( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSupp, * pSuppF;
+    int c, Delay = 0;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    for ( c = 0; c < pSupp->nSize; c++ )
+    {
+        pSuppF = Ivy_ObjSupp( pAig, Ivy_ManObj(pAig, pSupp->pArray[c]) );
+        Delay = IVY_MAX( Delay, pSuppF->Delay );
+    }
+    return 1 + Delay;
+}
+
+
+/**function*************************************************************
+
+  synopsis    [References the cut.]
+
+  description [This procedure is similar to the procedure NodeReclaim.]
+               
+  sideeffects []
+
+  seealso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeRef( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSupp, * pSuppF;
+    Ivy_Obj_t * pNodeChild;
+    int aArea, i;
+    // start the area of this cut
+    aArea = 1;
+    // go through the children
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->nSize > 1 );
+    for ( i = 0; i < pSupp->nSize; i++ )
+    {
+        pNodeChild = Ivy_ManObj(pAig, pSupp->pArray[i]);
+        pSuppF = Ivy_ObjSupp( pAig, pNodeChild );
+        assert( pSuppF->nRefs >= 0 );
+        if ( pSuppF->nRefs++ > 0 )  
+            continue;
+        if ( pSuppF->nSize == 1 ) 
+            continue;
+        aArea += Ivy_FastMapNodeRef( pAig, pNodeChild );
+    }
+    return aArea;
+}
+
+/**function*************************************************************
+
+  synopsis    [Dereferences the cut.]
+
+  description [This procedure is similar to the procedure NodeRecusiveDeref.]
+               
+  sideeffects []
+
+  seealso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeDeref( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSupp, * pSuppF;
+    Ivy_Obj_t * pNodeChild;
+    int aArea, i;
+    // start the area of this cut
+    aArea = 1;
+    // go through the children
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->nSize > 1 );
+    for ( i = 0; i < pSupp->nSize; i++ )
+    {
+        pNodeChild = Ivy_ManObj(pAig, pSupp->pArray[i]);
+        pSuppF = Ivy_ObjSupp( pAig, pNodeChild );
+        assert( pSuppF->nRefs > 0 );
+        if ( --pSuppF->nRefs > 0 )  
+            continue;
+        if ( pSuppF->nSize == 1 ) 
+            continue;
+        aArea += Ivy_FastMapNodeDeref( pAig, pNodeChild );
+    }
+    return aArea;
+}
+
+/**function*************************************************************
+
+  synopsis    [Computes the exact area associated with the cut.]
+
+  description []
+               
+  sideeffects []
+
+  seealso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeAreaRefed( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSupp;
+    int aResult, aResult2;
+    if ( Ivy_ObjIsCi(pObj) )
+        return 0;
+    assert( Ivy_ObjIsNode(pObj) );
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->nRefs > 0 );
+    aResult  = Ivy_FastMapNodeDeref( pAig, pObj );
+    aResult2 = Ivy_FastMapNodeRef( pAig, pObj );
+    assert( aResult == aResult2 );
+    return aResult;
+}
+
+/**function*************************************************************
+
+  synopsis    [Computes the exact area associated with the cut.]
+
+  description []
+               
+  sideeffects []
+
+  seealso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeAreaDerefed( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSupp;
+    int aResult, aResult2;
+    if ( Ivy_ObjIsCi(pObj) )
+        return 0;
+    assert( Ivy_ObjIsNode(pObj) );
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    assert( pSupp->nRefs == 0 );
+    aResult2 = Ivy_FastMapNodeRef( pAig, pObj );
+    aResult  = Ivy_FastMapNodeDeref( pAig, pObj );
+    assert( aResult == aResult2 );
+    return aResult;
+}
+
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Counts the number of nodes with no external fanout.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapCutCost( Ivy_Man_t * pAig, Vec_Ptr_t * vFront )
+{
+    Ivy_Supp_t * pSuppF;
+    Ivy_Obj_t * pFanin;
+    int i, Counter = 0;
+    Vec_PtrForEachEntry( vFront, pFanin, i )
+    {
+        pSuppF = Ivy_ObjSupp( pAig, pFanin );
+        if ( pSuppF->nRefs == 0 )
+            Counter++;
+    }
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs area recovery for each node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapMark_rec( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    if ( Ivy_ObjIsTravIdCurrent(pAig, pObj) )
+        return;
+    assert( Ivy_ObjIsNode(pObj) );
+    Ivy_FastMapMark_rec( pAig, Ivy_ObjFanin0(pObj) );
+    Ivy_FastMapMark_rec( pAig, Ivy_ObjFanin1(pObj) );
+    Ivy_ObjSetTravIdCurrent(pAig, pObj);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if the number of fanins will grow.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeWillGrow( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Obj_t * pFanin0, * pFanin1;
+    assert( Ivy_ObjIsNode(pObj) );
+    pFanin0 = Ivy_ObjFanin0(pObj);
+    pFanin1 = Ivy_ObjFanin1(pObj);
+    return !Ivy_ObjIsTravIdCurrent(pAig, pFanin0) && !Ivy_ObjIsTravIdCurrent(pAig, pFanin1);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the increase in the number of fanins with no external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeFaninCost( Ivy_Man_t * pAig, Ivy_Obj_t * pObj )
+{
+    Ivy_Supp_t * pSuppF;
+    Ivy_Obj_t * pFanin;
+    int Counter = 0;
+    assert( Ivy_ObjIsNode(pObj) );
+    // check if the node has external refs
+    pSuppF = Ivy_ObjSupp( pAig, pObj );
+    if ( pSuppF->nRefs == 0 )
+        Counter--;
+    // increment the number of fanins without external refs
+    pFanin = Ivy_ObjFanin0(pObj);
+    pSuppF = Ivy_ObjSupp( pAig, pFanin );
+    if ( !Ivy_ObjIsTravIdCurrent(pAig, pFanin) && pSuppF->nRefs == 0 )
+        Counter++;
+    // increment the number of fanins without external refs
+    pFanin = Ivy_ObjFanin1(pObj);
+    pSuppF = Ivy_ObjSupp( pAig, pFanin );
+    if ( !Ivy_ObjIsTravIdCurrent(pAig, pFanin) && pSuppF->nRefs == 0 )
+        Counter++;
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Updates the frontier.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeFaninUpdate( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, Vec_Ptr_t * vFront )
+{
+    Ivy_Obj_t * pFanin;
+    assert( Ivy_ObjIsNode(pObj) );
+    Vec_PtrRemove( vFront, pObj );
+    pFanin = Ivy_ObjFanin0(pObj);
+    if ( !Ivy_ObjIsTravIdCurrent(pAig, pFanin) )
+    {
+        Ivy_ObjSetTravIdCurrent(pAig, pFanin);
+        Vec_PtrPush( vFront, pFanin );
+    }
+    pFanin = Ivy_ObjFanin1(pObj);
+    if ( !Ivy_ObjIsTravIdCurrent(pAig, pFanin) )
+    {
+        Ivy_ObjSetTravIdCurrent(pAig, pFanin);
+        Vec_PtrPush( vFront, pFanin );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Compacts the number of external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeFaninCompact0( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront )
+{
+    Ivy_Obj_t * pFanin;
+    int i;
+    Vec_PtrForEachEntry( vFront, pFanin, i )
+    {
+        if ( Ivy_ObjIsCi(pFanin) )
+            continue;
+        if ( Ivy_FastMapNodeWillGrow(pAig, pFanin) )
+            continue;
+        if ( Ivy_FastMapNodeFaninCost(pAig, pFanin) <= 0 )
+        {
+            Ivy_FastMapNodeFaninUpdate( pAig, pFanin, vFront );
+            return 1;
+        }
+    }
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Compacts the number of external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeFaninCompact1( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront )
+{
+    Ivy_Obj_t * pFanin;
+    int i;
+    Vec_PtrForEachEntry( vFront, pFanin, i )
+    {
+        if ( Ivy_ObjIsCi(pFanin) )
+            continue;
+        if ( Ivy_FastMapNodeFaninCost(pAig, pFanin) < 0 )
+        {
+            Ivy_FastMapNodeFaninUpdate( pAig, pFanin, vFront );
+            return 1;
+        }
+    }
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Compacts the number of external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeFaninCompact2( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront )
+{
+    Ivy_Obj_t * pFanin;
+    int i;
+    Vec_PtrForEachEntry( vFront, pFanin, i )
+    {
+        if ( Ivy_ObjIsCi(pFanin) )
+            continue;
+        if ( Ivy_FastMapNodeFaninCost(pAig, pFanin) <= 0 )
+        {
+            Ivy_FastMapNodeFaninUpdate( pAig, pFanin, vFront );
+            return 1;
+        }
+    }
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Compacts the number of external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ivy_FastMapNodeFaninCompact_int( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront )
+{
+    if ( Ivy_FastMapNodeFaninCompact0(pAig, pObj, nLimit, vFront) )
+        return 1;
+    if (  Vec_PtrSize(vFront) < nLimit && Ivy_FastMapNodeFaninCompact1(pAig, pObj, nLimit, vFront) )
+        return 1;
+    if ( Vec_PtrSize(vFront) < nLimit && Ivy_FastMapNodeFaninCompact2(pAig, pObj, nLimit, vFront) )
+        return 1;
+    assert( Vec_PtrSize(vFront) <= nLimit );
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Compacts the number of external refs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeFaninCompact( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront )
+{
+    while ( Ivy_FastMapNodeFaninCompact_int( pAig, pObj, nLimit, vFront ) );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares node mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodePrepare( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront, Vec_Ptr_t * vFrontOld )
+{
+    Ivy_Supp_t * pSupp;
+    Ivy_Obj_t * pFanin;
+    int i;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    // expand the cut downwards from the given place
+    Vec_PtrClear( vFront );
+    Vec_PtrClear( vFrontOld );
+    Ivy_ManIncrementTravId( pAig );
+    for ( i = 0; i < pSupp->nSize; i++ )
+    {
+        pFanin = Ivy_ManObj(pAig, pSupp->pArray[i]);
+        Vec_PtrPush( vFront, pFanin );
+        Vec_PtrPush( vFrontOld, pFanin );
+        Ivy_ObjSetTravIdCurrent( pAig, pFanin );
+    }
+    // mark the nodes in the cone
+    Ivy_FastMapMark_rec( pAig, pObj );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Updates the frontier.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeUpdate( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, Vec_Ptr_t * vFront )
+{
+    Ivy_Supp_t * pSupp;
+    Ivy_Obj_t * pFanin;
+    int i;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    // deref node's cut
+    Ivy_FastMapNodeDeref( pAig, pObj );
+    // update the node's cut
+    pSupp->nSize = Vec_PtrSize(vFront);
+    Vec_PtrForEachEntry( vFront, pFanin, i )
+        pSupp->pArray[i] = pFanin->Id;
+    // ref the new cut
+    Ivy_FastMapNodeRef( pAig, pObj );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs area recovery for each node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeRecover2( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront, Vec_Ptr_t * vFrontOld )
+{
+    Ivy_Supp_t * pSupp;
+    int CostBef, CostAft;
+    int AreaBef, AreaAft;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+//    if ( pSupp->nRefs == 0 )
+//        return;
+    if ( pSupp->nRefs == 0 )
+        AreaBef = Ivy_FastMapNodeAreaDerefed( pAig, pObj );
+    else
+        AreaBef = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    // get the area
+    if ( AreaBef == 1 )
+        return;
+
+    if ( pSupp->nRefs == 0 )
+    {
+        pSupp->nRefs = 1000000;
+        Ivy_FastMapNodeRef( pAig, pObj );
+    }
+    // the cut is non-trivial
+    Ivy_FastMapNodePrepare( pAig, pObj, nLimit, vFront, vFrontOld );
+    // iteratively modify the cut
+    CostBef = Ivy_FastMapCutCost( pAig, vFront );
+    Ivy_FastMapNodeFaninCompact( pAig, pObj, nLimit, vFront );
+    CostAft = Ivy_FastMapCutCost( pAig, vFront );
+    assert( CostBef >= CostAft );
+    // update the node
+    Ivy_FastMapNodeUpdate( pAig, pObj, vFront );
+    // get the new area
+    AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    if ( AreaAft > AreaBef )
+    {
+        Ivy_FastMapNodeUpdate( pAig, pObj, vFrontOld );
+        AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+        assert( AreaAft == AreaBef );
+    }
+    if ( pSupp->nRefs == 1000000 )
+    {
+        pSupp->nRefs = 0;
+        Ivy_FastMapNodeDeref( pAig, pObj );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs area recovery for each node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeRecover( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront, Vec_Ptr_t * vFrontOld )
+{
+    Ivy_Supp_t * pSupp;
+    int CostBef, CostAft;
+    int AreaBef, AreaAft;
+    int DelayOld;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    DelayOld = pSupp->Delay = Ivy_FastMapNodeDelay( pAig, pObj );
+    assert( pSupp->Delay <= pSupp->DelayR );
+    if ( pSupp->nRefs == 0 )
+        return;
+    // get the area
+    AreaBef = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+//    if ( AreaBef == 1 )
+//        return;
+    if ( pObj->Id == 102 )
+    {
+        int x = 0;
+    }
+    // the cut is non-trivial
+    Ivy_FastMapNodePrepare( pAig, pObj, nLimit, vFront, vFrontOld );
+    // iteratively modify the cut
+    Ivy_FastMapNodeDeref( pAig, pObj );
+    CostBef = Ivy_FastMapCutCost( pAig, vFront );
+    Ivy_FastMapNodeFaninCompact( pAig, pObj, nLimit, vFront );
+    CostAft = Ivy_FastMapCutCost( pAig, vFront );
+    Ivy_FastMapNodeRef( pAig, pObj );
+    assert( CostBef >= CostAft );
+    // update the node
+    Ivy_FastMapNodeUpdate( pAig, pObj, vFront );
+    pSupp->Delay = Ivy_FastMapNodeDelay( pAig, pObj );
+    // get the new area
+    AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    if ( AreaAft > AreaBef || pSupp->Delay > pSupp->DelayR )
+    {
+        Ivy_FastMapNodeUpdate( pAig, pObj, vFrontOld );
+        AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+        assert( AreaAft == AreaBef );
+        pSupp->Delay = DelayOld;
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs area recovery for each node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ivy_FastMapNodeRecover4( Ivy_Man_t * pAig, Ivy_Obj_t * pObj, int nLimit, Vec_Ptr_t * vFront, Vec_Ptr_t * vFrontOld )
+{
+    Ivy_Supp_t * pSupp;
+    int CostBef, CostAft;
+    int AreaBef, AreaAft;
+    int DelayOld;
+    pSupp = Ivy_ObjSupp( pAig, pObj );
+    DelayOld = pSupp->Delay = Ivy_FastMapNodeDelay( pAig, pObj );
+    assert( pSupp->Delay <= pSupp->DelayR );
+//    if ( pSupp->nRefs == 0 )
+//        return;
+//    AreaBef = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    // get the area
+    if ( pSupp->nRefs == 0 )
+        AreaBef = Ivy_FastMapNodeAreaDerefed( pAig, pObj );
+    else
+        AreaBef = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    if ( AreaBef == 1 )
+        return;
+
+    if ( pSupp->nRefs == 0 )
+    {
+        pSupp->nRefs = 1000000;
+        Ivy_FastMapNodeRef( pAig, pObj );
+    }
+    // the cut is non-trivial
+    Ivy_FastMapNodePrepare( pAig, pObj, nLimit, vFront, vFrontOld );
+    // iteratively modify the cut
+    CostBef = Ivy_FastMapCutCost( pAig, vFront );
+    Ivy_FastMapNodeFaninCompact( pAig, pObj, nLimit, vFront );
+    CostAft = Ivy_FastMapCutCost( pAig, vFront );
+    assert( CostBef >= CostAft );
+    // update the node
+    Ivy_FastMapNodeUpdate( pAig, pObj, vFront );
+    pSupp->Delay = Ivy_FastMapNodeDelay( pAig, pObj );
+    // get the new area
+    AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+    if ( AreaAft > AreaBef || pSupp->Delay > pSupp->DelayR )
+    {
+        Ivy_FastMapNodeUpdate( pAig, pObj, vFrontOld );
+        AreaAft = Ivy_FastMapNodeAreaRefed( pAig, pObj );
+        assert( AreaAft == AreaBef );
+        pSupp->Delay = DelayOld;
+    }
+    if ( pSupp->nRefs == 1000000 )
+    {
+        pSupp->nRefs = 0;
+        Ivy_FastMapNodeDeref( pAig, pObj );
+    }
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+