Version abc90118

1 files changed, 971 insertions, 0 deletions

diff --git a/src/aig/saig/saigStrSim.c b/src/aig/saig/saigStrSim.c
new file mode 100644
index 00000000..ce4b8e05
--- /dev/null
+++ b/src/aig/saig/saigStrSim.c
@@ -0,0 +1,971 @@
+/**CFile****************************************************************
+
+  FileName    [saigStrSim.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Sequential AIG package.]
+
+  Synopsis    [Structural matching using simulation.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: saigStrSim.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "saig.h"
+#include "ssw.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+#define SAIG_WORDS  16
+
+static inline Aig_Obj_t *  Saig_ObjNext( Aig_Obj_t ** ppNexts, Aig_Obj_t * pObj )                       { return ppNexts[pObj->Id];  }
+static inline void         Saig_ObjSetNext( Aig_Obj_t ** ppNexts, Aig_Obj_t * pObj, Aig_Obj_t * pNext ) { ppNexts[pObj->Id] = pNext; }
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Computes hash value of the node using its simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+unsigned Saig_StrSimHash( Aig_Obj_t * pObj )
+{
+    static int s_SPrimes[128] = { 
+        1009, 1049, 1093, 1151, 1201, 1249, 1297, 1361, 1427, 1459, 
+        1499, 1559, 1607, 1657, 1709, 1759, 1823, 1877, 1933, 1997, 
+        2039, 2089, 2141, 2213, 2269, 2311, 2371, 2411, 2467, 2543, 
+        2609, 2663, 2699, 2741, 2797, 2851, 2909, 2969, 3037, 3089, 
+        3169, 3221, 3299, 3331, 3389, 3461, 3517, 3557, 3613, 3671, 
+        3719, 3779, 3847, 3907, 3943, 4013, 4073, 4129, 4201, 4243, 
+        4289, 4363, 4441, 4493, 4549, 4621, 4663, 4729, 4793, 4871, 
+        4933, 4973, 5021, 5087, 5153, 5227, 5281, 5351, 5417, 5471, 
+        5519, 5573, 5651, 5693, 5749, 5821, 5861, 5923, 6011, 6073, 
+        6131, 6199, 6257, 6301, 6353, 6397, 6481, 6563, 6619, 6689, 
+        6737, 6803, 6863, 6917, 6977, 7027, 7109, 7187, 7237, 7309, 
+        7393, 7477, 7523, 7561, 7607, 7681, 7727, 7817, 7877, 7933, 
+        8011, 8039, 8059, 8081, 8093, 8111, 8123, 8147
+    };
+    unsigned * pSims;
+    unsigned uHash = 0;
+    int i;
+    assert( SAIG_WORDS <= 128 );
+    pSims = pObj->pData;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        uHash ^= pSims[i] * s_SPrimes[i & 0x7F];
+    return uHash;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Computes hash value of the node using its simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimIsEqual( Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 )
+{
+    unsigned * pSims0 = pObj0->pData;
+    unsigned * pSims1 = pObj1->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        if ( pSims0[i] != pSims1[i] )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if simulation info is zero.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimIsZero( Aig_Obj_t * pObj )
+{
+    unsigned * pSims = pObj->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        if ( pSims[i] != 0 )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if simulation info is one.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimIsOne( Aig_Obj_t * pObj )
+{
+    unsigned * pSims = pObj->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        if ( pSims[i] != ~0 )
+            return 0;
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns random simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimAssignRandom( Aig_Obj_t * pObj )
+{
+    unsigned * pSims = pObj->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        pSims[i] = Aig_ManRandom(0);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns constant 0 simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimAssignOne( Aig_Obj_t * pObj )
+{
+    unsigned * pSims = pObj->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        pSims[i] = ~0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Assigns constant 0 simulation info.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimAssignZeroInit( Aig_Obj_t * pObj )
+{
+    unsigned * pSims = pObj->pData;
+    pSims[0] = 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Simulated one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimulateNode( Aig_Obj_t * pObj, int i )
+{
+    unsigned * pSims  = pObj->pData;
+    unsigned * pSims0 = Aig_ObjFanin0(pObj)->pData;
+    unsigned * pSims1 = Aig_ObjFanin1(pObj)->pData;
+    if ( Aig_ObjFaninC0(pObj) && Aig_ObjFaninC1(pObj) )
+        pSims[i] = ~(pSims0[i] | pSims1[i]);
+    else if ( Aig_ObjFaninC0(pObj) && !Aig_ObjFaninC1(pObj) )
+        pSims[i] = (~pSims0[i] & pSims1[i]);
+    else if ( !Aig_ObjFaninC0(pObj) && Aig_ObjFaninC1(pObj) )
+        pSims[i] = (pSims0[i] & ~pSims1[i]);
+    else // if ( !Aig_ObjFaninC0(pObj) && !Aig_ObjFaninC1(pObj) )
+        pSims[i] = (pSims0[i] & pSims1[i]);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Saves output of one node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimSaveOutput( Aig_Obj_t * pObj, int i )
+{
+    unsigned * pSims = pObj->pData;
+    unsigned * pSims0 = Aig_ObjFanin0(pObj)->pData;
+    if ( Aig_ObjFaninC0(pObj) )
+        pSims[i] = ~pSims0[i];
+    else 
+        pSims[i] = pSims0[i];
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Transfers simulation output to another node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimTransfer( Aig_Obj_t * pObj0, Aig_Obj_t * pObj1 )
+{
+    unsigned * pSims0 = pObj0->pData;
+    unsigned * pSims1 = pObj1->pData;
+    int i;
+    for ( i = 0; i < SAIG_WORDS; i++ )
+        pSims1[i] = pSims0[i];
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Transfers simulation output to another node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimTransferNext( Aig_Obj_t * pObj0, Aig_Obj_t * pObj1, int i )
+{
+    unsigned * pSims0 = pObj0->pData;
+    unsigned * pSims1 = pObj1->pData;
+    assert( i < SAIG_WORDS - 1 );
+    pSims1[i+1] = pSims0[i];
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Perform one round of simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimulateRound( Aig_Man_t * p0, Aig_Man_t * p1 )
+{
+    Aig_Obj_t * pObj0, * pObj1;
+    int f, i;
+    // simulate the nodes
+    Aig_ManForEachObj( p0, pObj0, i )
+    {
+        if ( !Aig_ObjIsPi(pObj0) && !Aig_ObjIsNode(pObj0) )
+           continue;
+        pObj1 = Aig_ObjRepr(p0, pObj0);
+        if ( pObj1 == NULL )
+            continue;
+        assert( Aig_ObjRepr(p1, pObj1) == pObj0 );
+        Saig_StrSimAssignRandom( pObj0 );
+        Saig_StrSimTransfer( pObj0, pObj1 );
+    }
+    // simulate the timeframes
+    for ( f = 0; f < SAIG_WORDS; f++ )
+    {
+        // simulate the first AIG
+        Aig_ManForEachNode( p0, pObj0, i )
+            if ( Aig_ObjRepr(p0, pObj0) == NULL )
+                Saig_StrSimulateNode( pObj0, f );
+        Saig_ManForEachLi( p0, pObj0, i )
+            Saig_StrSimSaveOutput( pObj0, f );
+        if ( f < SAIG_WORDS - 1 )
+            Saig_ManForEachLiLo( p0, pObj0, pObj1, i )
+                Saig_StrSimTransferNext( pObj0, pObj1, f );
+        // simulate the second AIG
+        Aig_ManForEachNode( p1, pObj1, i )
+            if ( Aig_ObjRepr(p1, pObj1) == NULL )
+                Saig_StrSimulateNode( pObj1, f );
+        Saig_ManForEachLi( p1, pObj1, i )
+            Saig_StrSimSaveOutput( pObj1, f );
+        if ( f < SAIG_WORDS - 1 )
+            Saig_ManForEachLiLo( p1, pObj1, pObj0, i )
+                Saig_StrSimTransferNext( pObj1, pObj0, f );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Checks if the entry exists in the table.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Obj_t * Saig_StrSimTableLookup( Aig_Obj_t ** ppTable, Aig_Obj_t ** ppNexts, int nTableSize, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pEntry;
+    int iEntry;
+    // find the hash entry
+    iEntry = Saig_StrSimHash( pObj ) % nTableSize;
+    // check if there are nodes with this signatures
+    for ( pEntry = ppTable[iEntry]; pEntry; pEntry = Saig_ObjNext(ppNexts,pEntry) )
+        if ( Saig_StrSimIsEqual( pEntry, pObj ) )
+            return pEntry;
+    return NULL;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Inserts the entry into the table.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimTableInsert( Aig_Obj_t ** ppTable, Aig_Obj_t ** ppNexts, int nTableSize, Aig_Obj_t * pObj )
+{
+    // find the hash entry
+    int iEntry = Saig_StrSimHash( pObj ) % nTableSize;
+    // check if there are nodes with this signatures
+    if ( ppTable[iEntry] == NULL )
+        ppTable[iEntry] = pObj;
+    else
+    {
+        Saig_ObjSetNext( ppNexts, pObj, Saig_ObjNext(ppNexts, ppTable[iEntry]) );
+        Saig_ObjSetNext( ppNexts, ppTable[iEntry], pObj );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Perform one round of matching.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimDetectUnique( Aig_Man_t * p0, Aig_Man_t * p1 )
+{
+    Aig_Obj_t ** ppTable, ** ppNexts, ** ppCands;
+    Aig_Obj_t * pObj, * pEntry;
+    int i, nTableSize, Counter;
+
+    // allocate the hash table hashing simulation info into nodes
+    nTableSize = Aig_PrimeCudd( Aig_ManObjNum(p0)/2 );
+    ppTable = CALLOC( Aig_Obj_t *, nTableSize ); 
+    ppNexts = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p0) ); 
+    ppCands = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p0) ); 
+
+    // hash nodes of the first AIG 
+    Aig_ManForEachObj( p0, pObj, i )
+    {
+        if ( !Aig_ObjIsPi(pObj) && !Aig_ObjIsNode(pObj) )
+            continue;
+        if ( Aig_ObjRepr(p0, pObj) )
+            continue;
+        if ( Saig_StrSimIsZero(pObj) || Saig_StrSimIsOne(pObj) )
+            continue;
+        // check if the entry exists
+        pEntry = Saig_StrSimTableLookup( ppTable, ppNexts, nTableSize, pObj );
+        if ( pEntry == NULL ) // insert
+            Saig_StrSimTableInsert( ppTable, ppNexts, nTableSize, pObj );
+        else // mark the entry as not unique
+            pEntry->fMarkA = 1;
+    }
+
+    // hash nodes from the second AIG
+    Aig_ManForEachObj( p1, pObj, i )
+    {
+        if ( !Aig_ObjIsPi(pObj) && !Aig_ObjIsNode(pObj) )
+            continue;
+        if ( Aig_ObjRepr(p1, pObj) )
+            continue;
+        if ( Saig_StrSimIsZero(pObj) || Saig_StrSimIsOne(pObj) )
+            continue;
+        // check if the entry exists
+        pEntry = Saig_StrSimTableLookup( ppTable, ppNexts, nTableSize, pObj );
+        if ( pEntry == NULL ) // skip
+            continue;
+        // if there is no candidate, label it
+        if ( Saig_ObjNext( ppCands, pEntry ) == NULL )
+            Saig_ObjSetNext( ppCands, pEntry, pObj );
+        else // mark the entry as not unique
+            pEntry->fMarkA = 1;
+    }
+
+    // create representatives for the unique entries
+    Counter = 0;
+    for ( i = 0; i < nTableSize; i++ )
+        for ( pEntry = ppTable[i]; pEntry; pEntry = Saig_ObjNext(ppNexts,pEntry) )
+            if ( !pEntry->fMarkA && (pObj = Saig_ObjNext( ppCands, pEntry )) )
+            {
+//                assert( Aig_ObjIsNode(pEntry) == Aig_ObjIsNode(pObj) );
+                if ( Aig_ObjType(pEntry) != Aig_ObjType(pObj) )
+                    continue;
+                Aig_ObjSetRepr( p0, pEntry, pObj );
+                Aig_ObjSetRepr( p1, pObj, pEntry );
+                Counter++;
+            }
+
+    // cleanup
+    Aig_ManCleanMarkA( p0 );
+    free( ppTable );
+    free( ppNexts );
+    free( ppCands );
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Counts the number of matched flops.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimCountMatchedFlops( Aig_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i, Counter = 0;
+    Saig_ManForEachLo( p, pObj, i )
+        if ( Aig_ObjRepr(p, pObj) )
+            Counter++;
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Counts the number of matched nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_StrSimCountMatchedNodes( Aig_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i, Counter = 0;
+    Aig_ManForEachNode( p, pObj, i )
+        if ( Aig_ObjRepr(p, pObj) )
+            Counter++;
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs structural matching of two AIGs using simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimPrepareAig( Aig_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i;
+    Aig_ManReprStart( p, Aig_ManObjNumMax(p) );
+    // allocate simulation info
+    p->pData2 = Vec_PtrAllocSimInfo( Aig_ManObjNumMax(p), SAIG_WORDS );
+    Aig_ManForEachObj( p, pObj, i )
+        pObj->pData = Vec_PtrEntry( p->pData2, i );
+    // set simulation info for constant1 and register outputs
+    Saig_StrSimAssignOne( Aig_ManConst1(p) );
+    Saig_ManForEachLo( p, pObj, i )
+        Saig_StrSimAssignZeroInit( pObj );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs structural matching of two AIGs using simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimSetInitMatching( Aig_Man_t * p0, Aig_Man_t * p1 )
+{
+    Aig_Obj_t * pObj0, * pObj1;
+    int i;
+    pObj0 = Aig_ManConst1( p0 );
+    pObj1 = Aig_ManConst1( p1 );
+    Aig_ObjSetRepr( p0, pObj0, pObj1 );
+    Aig_ObjSetRepr( p1, pObj1, pObj0 );
+    Saig_ManForEachPi( p0, pObj0, i )
+    {
+        pObj1 = Aig_ManPi( p1, i );
+        Aig_ObjSetRepr( p0, pObj0, pObj1 );
+        Aig_ObjSetRepr( p1, pObj1, pObj0 );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs structural matching of two AIGs using simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimSetFinalMatching( Aig_Man_t * p0, Aig_Man_t * p1 )
+{
+    Aig_Obj_t * pObj0, * pObj1;
+    Aig_Obj_t * pFanin00, * pFanin01;
+    Aig_Obj_t * pFanin10, * pFanin11;
+    int i, CountAll = 0, CountNot = 0;
+    Aig_ManIncrementTravId( p0 );
+    Aig_ManForEachObj( p0, pObj0, i )
+    {
+        pObj1 = Aig_ObjRepr( p0, pObj0 );
+        if ( pObj1 == NULL )
+            continue;
+        CountAll++;
+        assert( pObj0 == Aig_ObjRepr( p1, pObj1 ) );        
+        if ( Aig_ObjIsNode(pObj0) )
+        {
+            assert( Aig_ObjIsNode(pObj1) );
+            pFanin00 = Aig_ObjFanin0(pObj0);
+            pFanin01 = Aig_ObjFanin1(pObj0);
+            pFanin10 = Aig_ObjFanin0(pObj1);
+            pFanin11 = Aig_ObjFanin1(pObj1);
+            if ( Aig_ObjRepr(p0, pFanin00) != pFanin10 || 
+                 Aig_ObjRepr(p0, pFanin01) != pFanin11 )
+            {
+                Aig_ObjSetTravIdCurrent(p0, pObj0);
+                CountNot++;
+            }
+        }
+        else if ( Saig_ObjIsLo(p0, pObj0) )
+        {
+            assert( Saig_ObjIsLo(p1, pObj1) );
+            pFanin00 = Aig_ObjFanin0( Saig_ObjLoToLi(p0, pObj0) );
+            pFanin10 = Aig_ObjFanin0( Saig_ObjLoToLi(p1, pObj1) );
+            if ( Aig_ObjRepr(p0, pFanin00) != pFanin10 )
+            {
+                Aig_ObjSetTravIdCurrent(p0, pObj0);
+                CountNot++;
+            }
+        }
+    }
+    // remove irrelevant matches
+    Aig_ManForEachObj( p0, pObj0, i )
+    {
+        pObj1 = Aig_ObjRepr( p0, pObj0 );
+        if ( pObj1 == NULL )
+            continue;
+        assert( pObj0 == Aig_ObjRepr( p1, pObj1 ) );   
+        if ( Aig_ObjIsTravIdCurrent( p0, pObj0 ) )
+        {
+            Aig_ObjSetRepr( p0, pObj0, NULL );
+            Aig_ObjSetRepr( p1, pObj1, NULL );
+        }
+    }
+    printf( "Total matches = %6d.  Wrong matches = %6d.  Ratio = %5.2f %%\n", 
+        CountAll, CountNot, 100.0*CountNot/CountAll );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the number of dangling nodes removed.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimSetContiguousMatching_rec( Aig_Man_t * p, Aig_Obj_t * pObj )
+{
+    Aig_Obj_t * pFanout;
+    int i, iFanout = -1;
+    if ( Aig_ObjIsTravIdCurrent(p, pObj) )
+        return;
+    Aig_ObjSetTravIdCurrent(p, pObj);
+    if ( Saig_ObjIsPo( p, pObj ) )
+        return;
+    if ( Saig_ObjIsLi( p, pObj ) )
+    {
+        Saig_StrSimSetContiguousMatching_rec( p, Saig_ObjLiToLo(p, pObj) );
+        return;
+    }
+    assert( Aig_ObjIsPi(pObj) || Aig_ObjIsNode(pObj) );
+    if ( Aig_ObjRepr(p, pObj) == NULL )
+        return;
+    // go through the fanouts
+    Aig_ObjForEachFanout( p, pObj, pFanout, iFanout, i )
+        Saig_StrSimSetContiguousMatching_rec( p, pFanout );
+    // go through the fanins
+    if ( !Aig_ObjIsPi( pObj ) )
+    {
+        Saig_StrSimSetContiguousMatching_rec( p, Aig_ObjFanin0(pObj) );
+        Saig_StrSimSetContiguousMatching_rec( p, Aig_ObjFanin1(pObj) );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs structural matching of two AIGs using simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_StrSimSetContiguousMatching( Aig_Man_t * p0, Aig_Man_t * p1 )
+{
+    Aig_Obj_t * pObj0, * pObj1;
+    int i, CountAll = 0, CountNot = 0;
+    // mark nodes reachable through the PIs
+    Aig_ManIncrementTravId( p0 );
+    Aig_ObjSetTravIdCurrent( p0, Aig_ManConst1(p0) );
+    Saig_ManForEachPi( p0, pObj0, i )
+        Saig_StrSimSetContiguousMatching_rec( p0, pObj0 );
+    // remove irrelevant matches
+    Aig_ManForEachObj( p0, pObj0, i )
+    {
+        pObj1 = Aig_ObjRepr( p0, pObj0 );
+        if ( pObj1 == NULL )
+            continue;
+        CountAll++;
+        assert( pObj0 == Aig_ObjRepr( p1, pObj1 ) );   
+        if ( !Aig_ObjIsTravIdCurrent( p0, pObj0 ) )
+        {
+            Aig_ObjSetRepr( p0, pObj0, NULL );
+            Aig_ObjSetRepr( p1, pObj1, NULL );
+            CountNot++;
+        }
+    }
+    printf( "Total matches = %6d.  Wrong matches = %6d.  Ratio = %5.2f %%\n", 
+        CountAll, CountNot, 100.0*CountNot/CountAll );
+}
+
+
+
+/**Function*************************************************************
+
+  Synopsis    [Establishes relationship between nodes using pairing.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_StrSimMatchingExtendOne( Aig_Man_t * p, Vec_Ptr_t * vNodes )
+{
+    Aig_Obj_t * pNext, * pObj;
+    int i, k, iFan;
+    Vec_PtrClear( vNodes );
+    Aig_ManIncrementTravId( p );
+    Aig_ManForEachObj( p, pObj, i )
+    {
+        if ( !Aig_ObjIsNode(pObj) && !Aig_ObjIsPi(pObj) )
+            continue;
+        if ( Aig_ObjRepr( p, pObj ) != NULL )
+            continue;
+        if ( Saig_ObjIsLo(p, pObj) )
+        {
+            pNext = Saig_ObjLoToLi(p, pObj);
+            pNext = Aig_ObjFanin0(pNext);
+            if ( Aig_ObjRepr( p, pNext ) && !Aig_ObjIsTravIdCurrent(p, pNext) && !Aig_ObjIsConst1(pNext) )
+            {
+                Aig_ObjSetTravIdCurrent(p, pNext);
+                Vec_PtrPush( vNodes, pNext );
+            }
+        }
+        if ( Aig_ObjIsNode(pObj) )
+        {
+            pNext = Aig_ObjFanin0(pObj);
+            if ( Aig_ObjRepr( p, pNext )&& !Aig_ObjIsTravIdCurrent(p, pNext) )
+            {
+                Aig_ObjSetTravIdCurrent(p, pNext);
+                Vec_PtrPush( vNodes, pNext );
+            }
+            pNext = Aig_ObjFanin1(pObj);
+            if ( Aig_ObjRepr( p, pNext ) && !Aig_ObjIsTravIdCurrent(p, pNext) )
+            {
+                Aig_ObjSetTravIdCurrent(p, pNext);
+                Vec_PtrPush( vNodes, pNext );
+            }
+        }
+        Aig_ObjForEachFanout( p, pObj, pNext, iFan, k )  
+        {
+            if ( Saig_ObjIsPo(p, pNext) )
+                continue;
+            if ( Saig_ObjIsLi(p, pNext) )
+                pNext = Saig_ObjLiToLo(p, pNext);
+            if ( Aig_ObjRepr( p, pNext ) && !Aig_ObjIsTravIdCurrent(p, pNext) )
+            {
+                Aig_ObjSetTravIdCurrent(p, pNext);
+                Vec_PtrPush( vNodes, pNext );
+            }
+        }
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Establishes relationship between nodes using pairing.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Ssw_StrSimMatchingCountUnmached( Aig_Man_t * p )
+{
+    Aig_Obj_t * pObj;
+    int i, Counter = 0;
+    Aig_ManForEachObj( p, pObj, i )
+    {
+        if ( !Aig_ObjIsNode(pObj) && !Aig_ObjIsPi(pObj) )
+            continue;
+        if ( Aig_ObjRepr( p, pObj ) != NULL )
+            continue;
+        Counter++;
+    }
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Establishes relationship between nodes using pairing.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Ssw_StrSimMatchingExtend( Aig_Man_t * p0, Aig_Man_t * p1, int nDist, int fVerbose )
+{
+    Vec_Ptr_t * vNodes0, * vNodes1;
+    Aig_Obj_t * pNext0, * pNext1;
+    int d, k;
+    vNodes0 = Vec_PtrAlloc( 1000 );
+    vNodes1 = Vec_PtrAlloc( 1000 );
+    if ( fVerbose )
+    {
+        int nUnmached = Ssw_StrSimMatchingCountUnmached(p0);
+        printf( "Extending islands by %d steps:\n", nDist );
+        printf( "%2d : Total = %6d. Unmatched = %6d.  Ratio = %6.2f %%\n",
+            0, Aig_ManPiNum(p0) + Aig_ManNodeNum(p0), 
+            nUnmached, 100.0 * nUnmached/(Aig_ManPiNum(p0) + Aig_ManNodeNum(p0)) );
+    }
+    for ( d = 0; d < nDist; d++ )
+    {
+        Ssw_StrSimMatchingExtendOne( p0, vNodes0 );
+        Ssw_StrSimMatchingExtendOne( p1, vNodes1 );
+        Vec_PtrForEachEntry( vNodes0, pNext0, k )
+        {
+            pNext1 = Aig_ObjRepr( p0, pNext0 );
+            if ( pNext1 == NULL )
+                continue;
+            assert( pNext0 == Aig_ObjRepr( p1, pNext1 ) );
+            if ( Saig_ObjIsPi(p1, pNext1) )
+                continue;
+            Aig_ObjSetRepr( p0, pNext0, NULL );
+            Aig_ObjSetRepr( p1, pNext1, NULL );
+        }
+        Vec_PtrForEachEntry( vNodes1, pNext1, k )
+        {
+            pNext0 = Aig_ObjRepr( p1, pNext1 );
+            if ( pNext0 == NULL )
+                continue;
+            assert( pNext1 == Aig_ObjRepr( p0, pNext0 ) );
+            if ( Saig_ObjIsPi(p0, pNext0) )
+                continue;
+            Aig_ObjSetRepr( p0, pNext0, NULL );
+            Aig_ObjSetRepr( p1, pNext1, NULL );
+        }
+        if ( fVerbose )
+        {
+            int nUnmached = Ssw_StrSimMatchingCountUnmached(p0);
+            printf( "%2d : Total = %6d. Unmatched = %6d.  Ratio = %6.2f %%\n",
+                d+1, Aig_ManPiNum(p0) + Aig_ManNodeNum(p0), 
+                nUnmached, 100.0 * nUnmached/(Aig_ManPiNum(p0) + Aig_ManNodeNum(p0)) );
+        }
+    }
+    Vec_PtrFree( vNodes0 );
+    Vec_PtrFree( vNodes1 );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Performs structural matching of two AIGs using simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Int_t * Saig_StrSimPerformMatching( Aig_Man_t * p0, Aig_Man_t * p1, int nDist, int fVerbose, Aig_Man_t ** ppMiter )
+{
+    extern Aig_Man_t * Saig_ManWindowExtractMiter( Aig_Man_t * p0, Aig_Man_t * p1 );
+
+    Vec_Int_t * vPairs;
+    Aig_Man_t * pPart0, * pPart1;
+    Aig_Obj_t * pObj0, * pObj1;
+    int i, nMatches, clk, clkTotal = clock();
+    Aig_ManRandom( 1 );
+    // consider the case when a miter is given
+    if ( p1 == NULL )
+    {
+        if ( fVerbose )
+        {
+            Aig_ManPrintStats( p0 );
+        }
+        // demiter the miter
+        if ( !Saig_ManDemiterSimpleDiff( p0, &pPart0, &pPart1 ) )
+        {
+            printf( "Demitering has failed.\n" );
+            return NULL;
+        }
+    }
+    else
+    {
+        pPart0 = Aig_ManDupSimple( p0 );
+        pPart1 = Aig_ManDupSimple( p1 );
+    }
+    if ( fVerbose )
+    {
+        Aig_ManPrintStats( pPart0 );
+        Aig_ManPrintStats( pPart1 );
+    }
+    // start simulation 
+    Saig_StrSimPrepareAig( pPart0 );
+    Saig_StrSimPrepareAig( pPart1 );
+    Saig_StrSimSetInitMatching( pPart0, pPart1 );
+    if ( fVerbose )
+    {
+        printf( "Allocated %6.2f Mb to simulate the first AIG.\n", 
+            1.0 * Aig_ManObjNumMax(pPart0) * SAIG_WORDS * sizeof(unsigned) / (1<<20) );
+        printf( "Allocated %6.2f Mb to simulate the second AIG.\n", 
+            1.0 * Aig_ManObjNumMax(pPart1) * SAIG_WORDS * sizeof(unsigned) / (1<<20) );
+    }
+    // iterate matching
+    nMatches = 1;
+    for ( i = 0; nMatches > 0; i++ )
+    {
+        clk = clock();
+        Saig_StrSimulateRound( pPart0, pPart1 );
+        nMatches = Saig_StrSimDetectUnique( pPart0, pPart1 );
+        if ( fVerbose )
+        {
+            int nFlops = Saig_StrSimCountMatchedFlops(pPart0);
+            int nNodes = Saig_StrSimCountMatchedNodes(pPart0);
+            printf( "%3d : Match =%6d.  FF =%6d. (%6.2f %%)  Node =%6d. (%6.2f %%)  ",
+                i, nMatches,
+                nFlops, 100.0*nFlops/Aig_ManRegNum(pPart0),
+                nNodes, 100.0*nNodes/Aig_ManNodeNum(pPart0) );
+            PRT( "Time", clock() - clk );
+        }
+        if ( i == 20 )
+            break;
+    }
+    // cleanup
+    Vec_PtrFree( pPart0->pData2 ); pPart0->pData2 = NULL;
+    Vec_PtrFree( pPart1->pData2 ); pPart1->pData2 = NULL;
+    // extend the islands
+    Aig_ManFanoutStart( pPart0 );
+    Aig_ManFanoutStart( pPart1 );
+    if ( nDist )
+        Ssw_StrSimMatchingExtend( pPart0, pPart1, nDist, fVerbose );
+    Saig_StrSimSetFinalMatching( pPart0, pPart1 );
+//    Saig_StrSimSetContiguousMatching( pPart0, pPart1 );
+    // copy the results into array
+    vPairs = Vec_IntAlloc( 2*Aig_ManObjNumMax(pPart0) );
+    Aig_ManForEachObj( pPart0, pObj0, i )
+    {
+        pObj1 = Aig_ObjRepr(pPart0, pObj0);
+        if ( pObj1 == NULL )
+            continue;
+        assert( pObj0 == Aig_ObjRepr(pPart1, pObj1) );        
+        Vec_IntPush( vPairs, pObj0->Id );
+        Vec_IntPush( vPairs, pObj1->Id );
+    }
+    // this procedure adds matching of PO and LI
+    if ( ppMiter )
+        *ppMiter = Saig_ManWindowExtractMiter( pPart0, pPart1 );
+    Aig_ManFanoutStop( pPart0 );
+    Aig_ManFanoutStop( pPart1 );
+    Aig_ManStop( pPart0 );
+    Aig_ManStop( pPart1 );
+    PRT( "Total runtime", clock() - clkTotal );
+    return vPairs;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+