Version abc80912

14 files changed, 917 insertions, 22 deletions

diff --git a/abc.dsp b/abc.dsp
index 659a3f41..b4de5943 100644
--- a/abc.dsp
+++ b/abc.dsp
@@ -3306,6 +3306,10 @@ SOURCE=.\src\aig\saig\saigScl.c
 # End Source File
 # Begin Source File
 
+SOURCE=.\src\aig\saig\saigSynch.c
+# End Source File
+# Begin Source File
+
 SOURCE=.\src\aig\saig\saigTrans.c
 # End Source File
 # End Group
diff --git a/abc.rc b/abc.rc
index e0304667..a931fedb 100644
--- a/abc.rc
+++ b/abc.rc
@@ -1,8 +1,8 @@
 # global parameters
 #set check         # checks intermediate networks
 #set checkfio      # prints warnings when fanins/fanouts are duplicated
-#set checkread     # checks new networks after reading from file
-#set backup        # saves backup networks retrived by "undo" and "recall"
+set checkread     # checks new networks after reading from file
+set backup        # saves backup networks retrived by "undo" and "recall"
 set savesteps 1   # sets the maximum number of backup networks to save 
 set progressbar   # display the progress bar
 
diff --git a/src/aig/fra/fraSec.c b/src/aig/fra/fraSec.c
index b8f767df..9204c2a5 100644
--- a/src/aig/fra/fraSec.c
+++ b/src/aig/fra/fraSec.c
@@ -21,6 +21,7 @@
 #include "fra.h"
 #include "ioa.h"
 #include "int.h"
+#include "ssw.h"
 
 ////////////////////////////////////////////////////////////////////////
 ///                        DECLARATIONS                              ///
@@ -75,6 +76,7 @@ void Fra_SecSetDefaultParams( Fra_Sec_t * p )
 ***********************************************************************/
 int Fra_FraigSec( Aig_Man_t * p, Fra_Sec_t * pParSec )
 {
+    Ssw_Pars_t Pars2, * pPars2 = &Pars2;
     Fra_Ssw_t Pars, * pPars = &Pars;
     Fra_Sml_t * pSml;
     Aig_Man_t * pNew, * pTemp;
@@ -90,6 +92,8 @@ int Fra_FraigSec( Aig_Man_t * p, Fra_Sec_t * pParSec )
         goto finish;
 
     // prepare parameters
+    Ssw_ManSetDefaultParams( pPars2 );
+    // prepare parameters
     memset( pPars, 0, sizeof(Fra_Ssw_t) );
     pPars->fLatchCorr  = fLatchCorr;
     pPars->fVerbose = pParSec->fVeryVerbose;
@@ -288,12 +292,17 @@ PRT( "Time", clock() - clk );
                 goto finish;
             }
         }
-
+ 
 clk = clock();
         pPars->nFramesK = nFrames;
         pPars->TimeLimit = TimeLeft;
         pPars->fSilent = pParSec->fSilent;
-        pNew = Fra_FraigInduction( pTemp = pNew, pPars );
+//        pNew = Fra_FraigInduction( pTemp = pNew, pPars );
+
+        pPars2->nFramesK = nFrames;
+        pPars2->nBTLimit = 1000 * nFrames;
+        Aig_ManSetRegNum( pNew, pNew->nRegs );
+        pNew = Ssw_SignalCorrespondence( pTemp = pNew, pPars2 );
         if ( pNew == NULL )
         {
             pNew = pTemp;
@@ -306,7 +315,7 @@ clk = clock();
         if ( pParSec->fVerbose )
         { 
             printf( "K-step (K=%2d,I=%3d):  Latches = %5d. Nodes = %6d. ", 
-                nFrames, pPars->nIters, Aig_ManRegNum(pNew), Aig_ManNodeNum(pNew) );
+                nFrames, pPars2->nIters, Aig_ManRegNum(pNew), Aig_ManNodeNum(pNew) );
 PRT( "Time", clock() - clk );
         }
         if ( RetValue != -1 )
diff --git a/src/aig/saig/saig.h b/src/aig/saig/saig.h
index 88cc2c2d..da194f49 100644
--- a/src/aig/saig/saig.h
+++ b/src/aig/saig/saig.h
@@ -89,6 +89,7 @@ extern Aig_Man_t *       Saig_ManReadBlif( char * pFileName );
 extern int               Saig_Interpolate( Aig_Man_t * pAig, Inter_ManParams_t * pPars, int * pDepth );
 /*=== saigMiter.c ==========================================================*/
 extern Aig_Man_t *       Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper );
+extern Aig_Man_t *       Saig_ManDupInitZero( Aig_Man_t * p );
 /*=== saigPhase.c ==========================================================*/
 extern Aig_Man_t *       Saig_ManPhaseAbstract( Aig_Man_t * p, Vec_Int_t * vInits, int nFrames, int fIgnore, int fPrint, int fVerbose );
 /*=== saigRetFwd.c ==========================================================*/
diff --git a/src/aig/saig/saigMiter.c b/src/aig/saig/saigMiter.c
index 0c547257..5b18db6e 100644
--- a/src/aig/saig/saigMiter.c
+++ b/src/aig/saig/saigMiter.c
@@ -48,6 +48,7 @@ Aig_Man_t * Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper )
     assert( Saig_ManPiNum(p1) == Saig_ManPiNum(p2) );
     assert( Saig_ManPoNum(p1) == Saig_ManPoNum(p2) );
     pNew = Aig_ManStart( Aig_ManObjNumMax(p1) + Aig_ManObjNumMax(p2) );
+    pNew->pName = Aig_UtilStrsav( "miter" );
     // map constant nodes
     Aig_ManConst1(p1)->pData = Aig_ManConst1(pNew);
     Aig_ManConst1(p2)->pData = Aig_ManConst1(pNew);
@@ -88,6 +89,40 @@ Aig_Man_t * Saig_ManCreateMiter( Aig_Man_t * p1, Aig_Man_t * p2, int Oper )
     return pNew;
 }
 
+/**Function*************************************************************
+
+  Synopsis    [Duplicates the AIG to have constant-0 initial state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_ManDupInitZero( Aig_Man_t * p )
+{
+    Aig_Man_t * pNew;
+    Aig_Obj_t * pObj;
+    int i;
+    pNew = Aig_ManStart( Aig_ManObjNumMax(p) );
+    pNew->pName = Aig_UtilStrsav( p->pName );
+    Aig_ManConst1(p)->pData = Aig_ManConst1(pNew);
+    Saig_ManForEachPi( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePi( pNew );
+    Saig_ManForEachLo( p, pObj, i )
+        pObj->pData = Aig_NotCond( Aig_ObjCreatePi( pNew ), pObj->fMarkA );
+    Aig_ManForEachNode( p, pObj, i )
+        pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
+    Saig_ManForEachPo( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePo( pNew, Aig_ObjChild0Copy(pObj) );
+    Saig_ManForEachLi( p, pObj, i )
+        pObj->pData = Aig_ObjCreatePo( pNew, Aig_NotCond( Aig_ObjChild0Copy(pObj), pObj->fMarkA ) );
+    Aig_ManSetRegNum( pNew, Saig_ManRegNum(p) );
+    assert( Aig_ManNodeNum(pNew) == Aig_ManNodeNum(p) );
+    return pNew;
+}
+
 
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
diff --git a/src/aig/saig/saigSynch.c b/src/aig/saig/saigSynch.c
new file mode 100644
index 00000000..9dbbb420
--- /dev/null
+++ b/src/aig/saig/saigSynch.c
@@ -0,0 +1,623 @@
+/**CFile****************************************************************
+
+  FileName    [saigSynch.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Sequential AIG package.]
+
+  Synopsis    [Computation of synchronizing sequence.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: saigSynch.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "saig.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+//        0  1  x
+//       00 01 11
+// 0  00 00 00 00
+// 1  01 00 01 11
+// x  11 00 11 11
+
+static inline unsigned Saig_SynchNot( unsigned w )
+{
+    return w^((~(w&(w>>1)))&0x55555555);
+}
+static inline unsigned Saig_SynchAnd( unsigned u, unsigned w )
+{
+    return (u&w)|((((u&(u>>1)&w&~(w>>1))|(w&(w>>1)&u&~(u>>1)))&0x55555555)<<1);
+}
+static inline unsigned Saig_SynchRandomBinary() 
+{ 
+    return Aig_ManRandom(0) & 0x55555555;               
+}
+static inline unsigned Saig_SynchRandomTernary() 
+{ 
+    unsigned w = Aig_ManRandom(0);
+    return w^((~w)&(w>>1)&0x55555555);        
+}
+static inline unsigned Saig_SynchTernary( int v ) 
+{
+    assert( v == 0 || v == 1 || v == 3 );
+    return v? ((v==1)? 0x55555555 : 0xffffffff) : 0;
+}
+
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Initializes registers to the ternary state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchSetConstant1( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int w;
+    pObj = Aig_ManConst1( pAig );
+    pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+    for ( w = 0; w < nWords; w++ )
+        pSim[w] = 0x55555555;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Initializes registers to the ternary state.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchInitRegsTernary( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int i, w;
+    Saig_ManForEachLo( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim[w] = 0xffffffff;
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Initializes registers to the given binary state.]
+
+  Description [The binary state is stored in pObj->fMarkA.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchInitRegsBinary( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int i, w;
+    Saig_ManForEachLo( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim[w] = Saig_SynchTernary( pObj->fMarkA );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Initializes random binary primary inputs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchInitPisRandom( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int i, w;
+    Saig_ManForEachPi( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim[w] = Saig_SynchRandomBinary();
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Initializes random binary primary inputs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchInitPisGiven( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords, char * pValues )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int i, w;
+    Saig_ManForEachPi( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim[w] = Saig_SynchTernary( pValues[i] );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs ternary simulation of the nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchTernarySimulate( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim0, * pSim1, * pSim;
+    int i, w;
+    // simulate nodes
+    Aig_ManForEachNode( pAig, pObj, i )
+    {
+        pSim  = Vec_PtrEntry( vSimInfo, pObj->Id );
+        pSim0 = Vec_PtrEntry( vSimInfo, Aig_ObjFaninId0(pObj) );
+        pSim1 = Vec_PtrEntry( vSimInfo, Aig_ObjFaninId1(pObj) );
+        if ( Aig_ObjFaninC0(pObj) && Aig_ObjFaninC1(pObj) )
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = Saig_SynchAnd( Saig_SynchNot(pSim0[w]), Saig_SynchNot(pSim1[w]) );
+        }
+        else if ( !Aig_ObjFaninC0(pObj) && Aig_ObjFaninC1(pObj) )
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = Saig_SynchAnd( pSim0[w], Saig_SynchNot(pSim1[w]) );
+        }
+        else if ( Aig_ObjFaninC0(pObj) && !Aig_ObjFaninC1(pObj) )
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = Saig_SynchAnd( Saig_SynchNot(pSim0[w]), pSim1[w] );
+        }
+        else // if ( !Aig_ObjFaninC0(pObj) && !Aig_ObjFaninC1(pObj) )
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = Saig_SynchAnd( pSim0[w], pSim1[w] );
+        }
+    }
+    // transfer values to register inputs
+    Saig_ManForEachLi( pAig, pObj, i )
+    {
+        pSim  = Vec_PtrEntry( vSimInfo, pObj->Id );
+        pSim0 = Vec_PtrEntry( vSimInfo, Aig_ObjFaninId0(pObj) );
+        if ( Aig_ObjFaninC0(pObj) )
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = Saig_SynchNot( pSim0[w] );
+        }
+        else
+        {
+            for ( w = 0; w < nWords; w++ )
+                pSim[w] = pSim0[w];
+        }
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs ternary simulation of the nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Saig_SynchTernaryTransferState( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords )
+{
+    Aig_Obj_t * pObjLi, * pObjLo;
+    unsigned * pSim0, * pSim1;
+    int i, w;
+    Saig_ManForEachLiLo( pAig, pObjLi, pObjLo, i )
+    {
+        pSim0 = Vec_PtrEntry( vSimInfo, pObjLi->Id );
+        pSim1 = Vec_PtrEntry( vSimInfo, pObjLo->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim1[w] = pSim0[w];
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the number of Xs in the smallest ternary pattern.]
+
+  Description [Returns the number of this pattern.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_SynchCountX( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords, int * piPat )
+{
+    Aig_Obj_t * pObj;
+    unsigned * pSim;
+    int * pCounters, i, w, b;
+    int iPatBest, iTernMin;
+    // count the number of ternary values in each pattern
+    pCounters = CALLOC( int, nWords * 16 );
+    Saig_ManForEachLi( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        for ( w = 0; w < nWords; w++ )
+            for ( b = 0; b < 16; b++ )
+                if ( ((pSim[w] >> (b << 1)) & 3) == 3 )
+                    pCounters[16 * w + b]++;
+    }
+    // get the best pattern
+    iPatBest = -1;
+    iTernMin = 1 + Saig_ManRegNum(pAig);
+    for ( b = 0; b < 16 * nWords; b++ )
+        if ( iTernMin > pCounters[b] )
+        {
+            iTernMin = pCounters[b];
+            iPatBest = b;
+            if ( iTernMin == 0 )
+                break;
+        }
+    free( pCounters );
+    *piPat = iPatBest;
+    return iTernMin;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Saves the best pattern found and initializes the registers.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_SynchSavePattern( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, int nWords, int iPat, Vec_Str_t * vSequence )
+{
+    Aig_Obj_t * pObj, * pObjLi, * pObjLo;
+    unsigned * pSim;
+    int Counter, Value, i, w;
+    assert( iPat < 16 * nWords );
+    Saig_ManForEachPi( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        Value = (pSim[iPat>>4] >> ((iPat&0xf) << 1)) & 3;
+        Vec_StrPush( vSequence, (char)Value );
+//        printf( "%d ", Value );
+    }
+//    printf( "\n" );
+    Counter = 0;
+    Saig_ManForEachLiLo( pAig, pObjLi, pObjLo, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObjLi->Id );
+        Value = (pSim[iPat>>4] >> ((iPat&0xf) << 1)) & 3;
+        Counter += (Value == 3);
+        // save patern in the same register
+        pSim = Vec_PtrEntry( vSimInfo, pObjLo->Id );
+        for ( w = 0; w < nWords; w++ )
+            pSim[w] = Saig_SynchTernary( Value );
+    }
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Implement synchronizing sequence.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Saig_SynchSequenceRun( Aig_Man_t * pAig, Vec_Ptr_t * vSimInfo, Vec_Str_t * vSequence, int fTernary )
+{
+    unsigned * pSim;
+    Aig_Obj_t * pObj;
+    int Counter, nIters, Value, i;
+    assert( Vec_StrSize(vSequence) % Saig_ManPiNum(pAig) == 0 );
+    nIters = Vec_StrSize(vSequence) / Saig_ManPiNum(pAig);
+    Saig_SynchSetConstant1( pAig, vSimInfo, 1 );
+    if ( fTernary )
+        Saig_SynchInitRegsTernary( pAig, vSimInfo, 1 ); 
+    else
+        Saig_SynchInitRegsBinary( pAig, vSimInfo, 1 ); 
+    for ( i = 0; i < nIters; i++ )
+    {
+        Saig_SynchInitPisGiven( pAig, vSimInfo, 1, Vec_StrArray(vSequence) + i * Saig_ManPiNum(pAig) );
+        Saig_SynchTernarySimulate( pAig, vSimInfo, 1 );
+        Saig_SynchTernaryTransferState( pAig, vSimInfo, 1 );
+    }
+    // save the resulting state in the registers
+    Counter = 0;
+    Saig_ManForEachLo( pAig, pObj, i )
+    {
+        pSim = Vec_PtrEntry( vSimInfo, pObj->Id );
+        Value = pSim[0] & 3;
+        assert( Value != 2 );
+        Counter += (Value == 3);
+        pObj->fMarkA = Value;
+    }
+    return Counter;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Determines synchronizing sequence using ternary simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Vec_Str_t * Saig_SynchSequence( Aig_Man_t * pAig, int nWords )
+{
+    int nStepsMax = 100;  // the maximum number of simulation steps
+    int nTriesMax = 100;  // the maximum number of attempts at each step
+    int fVerify   =   1;  // verify the resulting pattern
+    Vec_Str_t * vSequence;
+    Vec_Ptr_t * vSimInfo;
+    int nTerPrev, nTerCur, nTerCur2;
+    int iPatBest, RetValue, s, t;
+    assert( Saig_ManRegNum(pAig) > 0 );
+    // reset random numbers
+    Aig_ManRandom( 1 );
+    // start the sequence
+    vSequence = Vec_StrAlloc( 20 * Saig_ManRegNum(pAig) );
+    // create sim info and init registers
+    vSimInfo = Vec_PtrAllocSimInfo( Aig_ManObjNumMax(pAig), nWords );
+    Saig_SynchSetConstant1( pAig, vSimInfo, nWords );
+    // iterate over the timeframes
+    nTerPrev = Saig_ManRegNum(pAig);
+    Saig_SynchInitRegsTernary( pAig, vSimInfo, nWords );
+    for ( s = 0; s < nStepsMax && nTerPrev > 0; s++ )
+    {
+        for ( t = 0; t < nTriesMax; t++ )
+        {
+            Saig_SynchInitPisRandom( pAig, vSimInfo, nWords );
+            Saig_SynchTernarySimulate( pAig, vSimInfo, nWords );
+            nTerCur = Saig_SynchCountX( pAig, vSimInfo, nWords, &iPatBest );
+            if ( nTerCur < nTerPrev )
+                break;
+        }
+        if ( t == nTriesMax )
+            break;
+        nTerCur2 = Saig_SynchSavePattern( pAig, vSimInfo, nWords, iPatBest, vSequence );
+        assert( nTerCur == nTerCur2 );
+        nTerPrev = nTerCur;
+    }
+    if ( nTerPrev > 0 )
+    {
+        printf( "Count not initialize %d registers.\n", nTerPrev );
+        Vec_PtrFree( vSimInfo );
+        Vec_StrFree( vSequence );
+        return NULL;
+    }
+    // verify that the sequence is correct
+    if ( fVerify )
+    {
+        RetValue = Saig_SynchSequenceRun( pAig, vSimInfo, vSequence, 1 );
+        assert( RetValue == 0 );
+        Aig_ManCleanMarkA( pAig );
+    }
+    Vec_PtrFree( vSimInfo );
+    return vSequence;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Determines synchronizing sequence using ternary simulation.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_SynchSequenceApply( Aig_Man_t * pAig, int nWords, int fVerbose )
+{
+    Aig_Man_t * pAigZero;
+    Vec_Str_t * vSequence;
+    Vec_Ptr_t * vSimInfo;
+    int RetValue, clk;
+
+clk = clock();
+    // derive synchronization sequence
+    vSequence = Saig_SynchSequence( pAig, nWords );
+    if ( vSequence == NULL )
+        printf( "Design 1: Synchronizing sequence is not found. " );
+    else if ( fVerbose )
+        printf( "Design 1: Synchronizing sequence of length %4d is found. ", Vec_StrSize(vSequence) / Saig_ManPiNum(pAig) );
+    if ( fVerbose )
+    {
+        PRT( "Time", clock() - clk );
+    }
+    else
+        printf( "\n" );
+    if ( vSequence == NULL )
+    {
+        printf( "Quitting synchronization.\n" );
+        return NULL;
+    }
+
+    // apply synchronization sequence
+    vSimInfo = Vec_PtrAllocSimInfo( Aig_ManObjNumMax(pAig), 1 );
+    RetValue = Saig_SynchSequenceRun( pAig, vSimInfo, vSequence, 1 );
+    assert( RetValue == 0 );
+    // duplicate 
+    pAigZero = Saig_ManDupInitZero( pAig );
+    // cleanup
+    Vec_PtrFree( vSimInfo );
+    Vec_StrFree( vSequence );
+    Aig_ManCleanMarkA( pAig );
+    return pAigZero;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Creates SEC miter for two designs without initial state.]
+
+  Description [The designs (pAig1 and pAig2) are assumed to have ternary 
+  initial state. Determines synchronizing sequences using ternary simulation.
+  Simulates the sequences on both designs to come up with equivalent binary 
+  initial states. Create seq miter for the designs starting in these states.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Aig_Man_t * Saig_Synchronize( Aig_Man_t * pAig1, Aig_Man_t * pAig2, int nWords, int fVerbose )
+{
+    Aig_Man_t * pAig1z, * pAig2z, * pMiter;
+    Vec_Str_t * vSeq1, * vSeq2;
+    Vec_Ptr_t * vSimInfo;
+    int RetValue, clk;
+/*
+    {
+        unsigned u = Saig_SynchRandomTernary();
+        unsigned w = Saig_SynchRandomTernary();
+        unsigned x = Saig_SynchNot( u );
+        unsigned y = Saig_SynchNot( w );
+        unsigned z = Saig_SynchAnd( x, y );
+
+        Extra_PrintBinary( stdout, &u, 32 );  printf( "\n" );
+        Extra_PrintBinary( stdout, &w, 32 );  printf( "\n" );  printf( "\n" );
+        Extra_PrintBinary( stdout, &x, 32 );  printf( "\n" );
+        Extra_PrintBinary( stdout, &y, 32 );  printf( "\n" );  printf( "\n" );
+        Extra_PrintBinary( stdout, &z, 32 );  printf( "\n" );
+    }
+*/
+    // report statistics
+    if ( fVerbose )
+    {
+        printf( "Design 1: " );
+        Aig_ManPrintStats( pAig1 );
+        printf( "Design 2: " );
+        Aig_ManPrintStats( pAig2 );
+    }
+
+    // synchronize the first design
+    clk = clock();
+    vSeq1 = Saig_SynchSequence( pAig1, nWords );
+    if ( vSeq1 == NULL )
+        printf( "Design 1: Synchronizing sequence is not found. " );
+    else if ( fVerbose )
+        printf( "Design 1: Synchronizing sequence of length %4d is found. ", Vec_StrSize(vSeq1) / Saig_ManPiNum(pAig1) );
+    if ( fVerbose )
+    {
+        PRT( "Time", clock() - clk );
+    }
+    else
+        printf( "\n" );
+
+    // synchronize the first design
+    clk = clock();
+    vSeq2 = Saig_SynchSequence( pAig2, nWords );
+    if ( vSeq2 == NULL )
+        printf( "Design 2: Synchronizing sequence is not found. " );
+    else if ( fVerbose )
+        printf( "Design 2: Synchronizing sequence of length %4d is found. ", Vec_StrSize(vSeq2) / Saig_ManPiNum(pAig2) );
+    if ( fVerbose )
+    {
+        PRT( "Time", clock() - clk );
+    }
+    else
+        printf( "\n" );
+
+    // quit if one of the designs cannot be synchronized
+    if ( vSeq1 == NULL || vSeq2 == NULL )
+    {
+        printf( "Quitting synchronization.\n" );
+        if ( vSeq1 ) Vec_StrFree( vSeq1 );
+        if ( vSeq2 ) Vec_StrFree( vSeq2 );
+        return NULL;
+    }
+    clk = clock();
+    vSimInfo = Vec_PtrAllocSimInfo( AIG_MAX( Aig_ManObjNumMax(pAig1), Aig_ManObjNumMax(pAig2) ), 1 );
+
+    // process Design 1
+    RetValue = Saig_SynchSequenceRun( pAig1, vSimInfo, vSeq1, 1 );
+    assert( RetValue == 0 );
+    RetValue = Saig_SynchSequenceRun( pAig1, vSimInfo, vSeq2, 0 );
+    assert( RetValue == 0 );
+
+    // process Design 2
+    RetValue = Saig_SynchSequenceRun( pAig2, vSimInfo, vSeq2, 1 );
+    assert( RetValue == 0 );
+
+    // duplicate designs
+    pAig1z = Saig_ManDupInitZero( pAig1 );
+    pAig2z = Saig_ManDupInitZero( pAig2 );
+    pMiter = Saig_ManCreateMiter( pAig1z, pAig2z, 0 );
+    Aig_ManStop( pAig1z );
+    Aig_ManStop( pAig2z );
+
+    // cleanup
+    Vec_PtrFree( vSimInfo );
+    Vec_StrFree( vSeq1 );
+    Vec_StrFree( vSeq2 );
+    Aig_ManCleanMarkA( pAig1 );
+    Aig_ManCleanMarkA( pAig2 );
+
+    if ( fVerbose )
+    {
+        printf( "Miter of the synchronized designs is constructed.         " );
+        PRT( "Time", clock() - clk );
+    }
+    return pMiter;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
diff --git a/src/aig/ssw/sswCore.c b/src/aig/ssw/sswCore.c
index e6096c54..b03a248e 100644
--- a/src/aig/ssw/sswCore.c
+++ b/src/aig/ssw/sswCore.c
@@ -139,8 +139,9 @@ clk = clock();
             printf( "%3d : Const = %6d. Cl = %6d. LR = %6d. NR = %6d. F = %5d. ", 
                 nIter, Ssw_ClassesCand1Num(p->ppClasses), Ssw_ClassesClassNum(p->ppClasses), 
                 p->nConstrReduced, Aig_ManNodeNum(p->pFrames), p->nSatFailsReal );
-            printf( "Use = %5d. Skip = %5d. ", 
-                p->nRefUse, p->nRefSkip );
+            if ( p->pPars->fSkipCheck )
+                printf( "Use = %5d. Skip = %5d. ", 
+                    p->nRefUse, p->nRefSkip );
             PRT( "T", clock() - clk );
         } 
         Ssw_ManCleanup( p );
diff --git a/src/aig/ssw/sswMan.c b/src/aig/ssw/sswMan.c
index f25cee45..559f7b6c 100644
--- a/src/aig/ssw/sswMan.c
+++ b/src/aig/ssw/sswMan.c
@@ -47,14 +47,14 @@ Ssw_Man_t * Ssw_ManCreate( Aig_Man_t * pAig, Ssw_Pars_t * pPars )
     Aig_ManFanoutStart( pAig );
     Aig_ManSetPioNumbers( pAig );
     // create interpolation manager
-    p = ALLOC( Ssw_Man_t, 1 );
+    p = ALLOC( Ssw_Man_t, 1 ); 
     memset( p, 0, sizeof(Ssw_Man_t) );
     p->pPars         = pPars;
     p->pAig          = pAig;
     p->nFrames       = pPars->nFramesK + 1;
     p->pNodeToFraig  = CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(p->pAig) * p->nFrames );
     // SAT solving
-    p->pSatVars      = CALLOC( int, Aig_ManObjNumMax(p->pAig) * p->nFrames );
+    p->pSatVars      = CALLOC( int, Aig_ManObjNumMax(p->pAig) * (p->nFrames+1) );
     p->vFanins       = Vec_PtrAlloc( 100 );
     p->vSimRoots     = Vec_PtrAlloc( 1000 );
     p->vSimClasses   = Vec_PtrAlloc( 1000 );
@@ -99,8 +99,8 @@ void Ssw_ManPrintStats( Ssw_Man_t * p )
 {
     double nMemory = 1.0*Aig_ManObjNumMax(p->pAig)*p->nFrames*(2*sizeof(int)+2*sizeof(void*))/(1<<20);
 
-    printf( "Parameters: Fr = %d. C-limit = %d. Constr = %d. SkipCheck = %d. MaxLev = %d. Mem = %0.2f Mb.\n", 
-        p->pPars->nFramesK, p->pPars->nBTLimit, p->pPars->nConstrs, p->pPars->fSkipCheck, p->pPars->nMaxLevs, nMemory );
+    printf( "Parameters: F = %d. AddF = %d. C-lim = %d. Constr = %d. SkipCheck = %d. MaxLev = %d. Mem = %0.2f Mb.\n", 
+        p->pPars->nFramesK, p->pPars->nFramesAddSim, p->pPars->nBTLimit, p->pPars->nConstrs, p->pPars->fSkipCheck, p->pPars->nMaxLevs, nMemory );
     printf( "AIG       : PI = %d. PO = %d. Latch = %d. Node = %d.  Ave SAT vars = %d.\n", 
         Saig_ManPiNum(p->pAig), Saig_ManPoNum(p->pAig), Saig_ManRegNum(p->pAig), Aig_ManNodeNum(p->pAig), 
         p->nSatVarsTotal/p->pPars->nIters );
@@ -149,7 +149,7 @@ void Ssw_ManCleanup( Ssw_Man_t * p )
         p->nSatVarsTotal += p->pSat->size;
         sat_solver_delete( p->pSat );
         p->pSat = NULL;
-        memset( p->pSatVars, 0, sizeof(int) * Aig_ManObjNumMax(p->pAig) * p->nFrames );
+        memset( p->pSatVars, 0, sizeof(int) * Aig_ManObjNumMax(p->pAig) * (p->nFrames+1) );
     }
     p->nConstrTotal = 0;
     p->nConstrReduced = 0;
diff --git a/src/aig/ssw/sswSimSat.c b/src/aig/ssw/sswSimSat.c
index 6ef5ec20..3fa39612 100644
--- a/src/aig/ssw/sswSimSat.c
+++ b/src/aig/ssw/sswSimSat.c
@@ -234,7 +234,6 @@ void Ssw_ManResimulateCexTotal( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pR
     // set the PI simulation information
     Aig_ManConst1(p->pAig)->fMarkB = 1;
     Aig_ManForEachPi( p->pAig, pObj, i )
-//        pObj->fMarkB = Ssw_ManOriginalPiValue( p, pObj, f );
         pObj->fMarkB = Aig_InfoHasBit( p->pPatWords, i );
     // simulate internal nodes
     Aig_ManForEachNode( p->pAig, pObj, i )
@@ -244,10 +243,18 @@ void Ssw_ManResimulateCexTotal( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pR
     RetValue1 = Ssw_ClassesRefineConst1( p->ppClasses, 0 );
     RetValue2 = Ssw_ClassesRefine( p->ppClasses, 0 );
     // make sure refinement happened
-    if ( Aig_ObjIsConst1(pRepr) )
+    if ( Aig_ObjIsConst1(pRepr) ) 
+    {
         assert( RetValue1 );
+        if ( RetValue1 == 0 )
+            printf( "\nSsw_ManResimulateCexTotal() Error: RetValue1 does not hold.\n" );
+    }
     else
+    {
         assert( RetValue2 );
+        if ( RetValue2 == 0 )
+            printf( "\nSsw_ManResimulateCexTotal() Error: RetValue2 does not hold.\n" );
+    }
 p->timeSimSat += clock() - clk;
 }
 
@@ -266,8 +273,6 @@ p->timeSimSat += clock() - clk;
 void Ssw_ManResimulateCexTotalSim( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t * pRepr, int f )
 {
     int RetValue1, RetValue2, clk = clock();
-    // save the counter-example
-//    Ssw_SmlSavePatternAig( p, f );
     // set the PI simulation information
     Ssw_SmlAssignDist1Plus( p->pSml, p->pPatWords );
     // simulate internal nodes
@@ -277,9 +282,17 @@ void Ssw_ManResimulateCexTotalSim( Ssw_Man_t * p, Aig_Obj_t * pCand, Aig_Obj_t *
     RetValue2 = Ssw_ClassesRefine( p->ppClasses, 1 );
     // make sure refinement happened
     if ( Aig_ObjIsConst1(pRepr) )
+    {
         assert( RetValue1 );
+        if ( RetValue1 == 0 )
+            printf( "\nSsw_ManResimulateCexTotalSim() Error: RetValue1 does not hold.\n" );
+    }
     else
+    {
         assert( RetValue2 );
+        if ( RetValue2 == 0 )
+            printf( "\nSsw_ManResimulateCexTotalSim() Error: RetValue2 does not hold.\n" );
+    }
 p->timeSimSat += clock() - clk;
 }
 
diff --git a/src/aig/ssw/sswSweep.c b/src/aig/ssw/sswSweep.c
index 5ad6d78e..3dccc08d 100644
--- a/src/aig/ssw/sswSweep.c
+++ b/src/aig/ssw/sswSweep.c
@@ -222,6 +222,7 @@ clk = clock();
     p->fRefined = 0;
     if ( p->pPars->fVerbose )
         pProgress = Bar_ProgressStart( stdout, Aig_ManObjNumMax(p->pAig) * p->pPars->nFramesK );
+    Ssw_ManStartSolver( p );
     for ( f = 0; f < p->pPars->nFramesK; f++ )
     {
         // map constants and PIs
@@ -241,8 +242,13 @@ clk = clock();
         if ( f == p->pPars->nFramesK - 1 )
             break;
         // transfer latch input to the latch outputs 
+        // build logic cones for register outputs
         Saig_ManForEachLiLo( p->pAig, pObjLi, pObjLo, i )
-            Ssw_ObjSetFraig( p, pObjLo, f+1, Ssw_ObjChild0Fra(p, pObjLi,f) );
+        {
+            pObjNew = Ssw_ObjChild0Fra(p, pObjLi,f);
+            Ssw_ObjSetFraig( p, pObjLo, f+1, pObjNew );
+            Ssw_CnfNodeAddToSolver( p, Aig_Regular(pObjNew) );
+        }
     }
     if ( p->pPars->fVerbose )
         Bar_ProgressStop( pProgress );
diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index 3c7314ef..0db761c7 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -199,6 +199,7 @@ static int Abc_CommandCycle          ( Abc_Frame_t * pAbc, int argc, char ** arg
 static int Abc_CommandXsim           ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandSim            ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandDarPhase       ( Abc_Frame_t * pAbc, int argc, char ** argv );
+static int Abc_CommandSynch          ( Abc_Frame_t * pAbc, int argc, char ** argv );
 
 static int Abc_CommandCec            ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandDCec           ( Abc_Frame_t * pAbc, int argc, char ** argv );
@@ -463,6 +464,7 @@ void Abc_Init( Abc_Frame_t * pAbc )
     Cmd_CommandAdd( pAbc, "Sequential",   "xsim",          Abc_CommandXsim,             0 );
     Cmd_CommandAdd( pAbc, "Sequential",   "sim",           Abc_CommandSim,              0 );
     Cmd_CommandAdd( pAbc, "Sequential",   "phase",         Abc_CommandDarPhase,         1 );
+    Cmd_CommandAdd( pAbc, "Sequential",   "synch",         Abc_CommandSynch,            1 );
 
     Cmd_CommandAdd( pAbc, "Verification", "cec",           Abc_CommandCec,              0 );
     Cmd_CommandAdd( pAbc, "Verification", "dcec",          Abc_CommandDCec,             0 );
@@ -4862,7 +4864,6 @@ int Abc_CommandMiter( Abc_Frame_t * pAbc, int argc, char ** argv )
     nArgcNew = argc - globalUtilOptind;
     if ( !Abc_NtkPrepareTwoNtks( pErr, pNtk, pArgvNew, nArgcNew, &pNtk1, &pNtk2, &fDelete1, &fDelete2 ) )
         return 1;
-
     // compute the miter
     pNtkRes = Abc_NtkMiter( pNtk1, pNtk2, fComb, nPartSize, fImplic, fMulti );
     if ( fDelete1 ) Abc_NtkDelete( pNtk1 );
@@ -14424,6 +14425,121 @@ usage:
     return 1;
 }
 
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_CommandSynch( Abc_Frame_t * pAbc, int argc, char ** argv )
+{
+    FILE * pOut, * pErr;
+    Abc_Ntk_t * pNtkRes, * pNtk1, * pNtk2, * pNtk;
+    char ** pArgvNew;
+    int nArgcNew;
+    int fDelete1, fDelete2;
+    int c;
+    int nWords;
+    int fVerbose;
+
+    extern Abc_Ntk_t * Abc_NtkDarSynch( Abc_Ntk_t * pNtk1, Abc_Ntk_t * pNtk2, int nWords, int fVerbose );
+    extern Abc_Ntk_t * Abc_NtkDarSynchOne( Abc_Ntk_t * pNtk, int nWords, int fVerbose );
+
+    pNtk = Abc_FrameReadNtk(pAbc);
+    pOut = Abc_FrameReadOut(pAbc);
+    pErr = Abc_FrameReadErr(pAbc);
+
+    // set defaults
+    nWords   =  32;
+    fVerbose =   1;
+    Extra_UtilGetoptReset();
+    while ( ( c = Extra_UtilGetopt( argc, argv, "Wvh" ) ) != EOF )
+    {
+        switch ( c )
+        {
+        case 'W':
+            if ( globalUtilOptind >= argc )
+            {
+                fprintf( pErr, "Command line switch \"-W\" should be followed by an integer.\n" );
+                goto usage;
+            }
+            nWords = atoi(argv[globalUtilOptind]);
+            globalUtilOptind++;
+            if ( nWords <= 0 ) 
+                goto usage;
+            break;
+        case 'v':
+            fVerbose ^= 1;
+            break;
+        case 'h':
+            goto usage;
+        default:
+            goto usage;
+        }
+    }
+
+    pArgvNew = argv + globalUtilOptind;
+    nArgcNew = argc - globalUtilOptind;
+    if ( nArgcNew == 0 )
+    {
+        if ( pNtk == NULL )
+        {
+            fprintf( pErr, "Empty network.\n" );
+            return 1;
+        }
+        pNtkRes = Abc_NtkDarSynchOne( pNtk, nWords, fVerbose );
+    }
+    else
+    {
+        if ( !Abc_NtkPrepareTwoNtks( pErr, pNtk, pArgvNew, nArgcNew, &pNtk1, &pNtk2, &fDelete1, &fDelete2 ) )
+            return 1;
+        if ( Abc_NtkLatchNum(pNtk1) == 0 || Abc_NtkLatchNum(pNtk2) == 0 )
+        {
+            if ( fDelete1 ) Abc_NtkDelete( pNtk1 );
+            if ( fDelete2 ) Abc_NtkDelete( pNtk2 );
+            printf( "The network has no latches..\n" );
+            return 0;
+        }
+
+        // modify the current network
+        pNtkRes = Abc_NtkDarSynch( pNtk1, pNtk2, nWords, fVerbose );
+        if ( fDelete1 ) Abc_NtkDelete( pNtk1 );
+        if ( fDelete2 ) Abc_NtkDelete( pNtk2 );
+    }
+    if ( pNtkRes == NULL )
+    {
+        fprintf( pErr, "Synchronization has failed.\n" );
+        return 0;
+    }
+    // replace the current network
+    Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
+    return 0;
+
+usage:
+    fprintf( pErr, "usage: synch [-W <num>] [-vh] <file1> <file2>\n" );
+    fprintf( pErr, "\t         derives and applies synchronization sequence\n" );
+    fprintf( pErr, "\t-W num : the number of simulation words [default = %d]\n", nWords );
+    fprintf( pErr, "\t-v     : toggle verbose output [default = %s]\n", fVerbose? "yes": "no" );
+    fprintf( pErr, "\t-h     : print the command usage\n");
+    fprintf( pErr, "\tfile1  : (optional) the file with the first design\n");
+    fprintf( pErr, "\tfile2  : (optional) the file with the second design\n\n");
+    fprintf( pErr, "\t         If no designs are given on the command line,\n" );
+    fprintf( pErr, "\t         assumes the current network has no initial state,\n" );
+    fprintf( pErr, "\t         derives synchronization sequence and applies it.\n\n" );
+    fprintf( pErr, "\t         If two designs are given on the command line\n" );
+    fprintf( pErr, "\t         assumes both of them have no initial state,\n" );
+    fprintf( pErr, "\t         derives sequences for both designs, synchorinizes\n" );
+    fprintf( pErr, "\t         them, and creates SEC miter comparing two designs.\n\n" );
+    fprintf( pErr, "\t         If only one design is given on the command line,\n" );
+    fprintf( pErr, "\t         considers the second design to be the current network,\n" );
+    fprintf( pErr, "\t         and derives SEC miter for them, as described above.\n" );
+    return 1;
+}
 
 
 /**Function*************************************************************
@@ -14842,6 +14958,8 @@ int Abc_CommandSec( Abc_Frame_t * pAbc, int argc, char ** argv )
 
     if ( Abc_NtkLatchNum(pNtk1) == 0 || Abc_NtkLatchNum(pNtk2) == 0 )
     {
+        if ( fDelete1 ) Abc_NtkDelete( pNtk1 );
+        if ( fDelete2 ) Abc_NtkDelete( pNtk2 );
         printf( "The network has no latches. Used combinational command \"cec\".\n" );
         return 0;
     }
@@ -14960,9 +15078,10 @@ int Abc_CommandDSec( Abc_Frame_t * pAbc, int argc, char ** argv )
     nArgcNew = argc - globalUtilOptind;
     if ( !Abc_NtkPrepareTwoNtks( pErr, pNtk, pArgvNew, nArgcNew, &pNtk1, &pNtk2, &fDelete1, &fDelete2 ) )
         return 1;
-
     if ( Abc_NtkLatchNum(pNtk1) == 0 || Abc_NtkLatchNum(pNtk2) == 0 )
     {
+        if ( fDelete1 ) Abc_NtkDelete( pNtk1 );
+        if ( fDelete2 ) Abc_NtkDelete( pNtk2 );
         printf( "The network has no latches. Used combinational command \"cec\".\n" );
         return 0;
     }
diff --git a/src/base/abci/abcDar.c b/src/base/abci/abcDar.c
index 37cd6853..f1e5efb0 100644
--- a/src/base/abci/abcDar.c
+++ b/src/base/abci/abcDar.c
@@ -2195,6 +2195,71 @@ Abc_Ntk_t * Abc_NtkPhaseAbstract( Abc_Ntk_t * pNtk, int nFrames, int fIgnore, in
   SeeAlso     []
 
 ***********************************************************************/
+Abc_Ntk_t * Abc_NtkDarSynchOne( Abc_Ntk_t * pNtk, int nWords, int fVerbose )
+{
+    extern Aig_Man_t * Saig_SynchSequenceApply( Aig_Man_t * pAig, int nWords, int fVerbose );
+    Abc_Ntk_t * pNtkAig;
+    Aig_Man_t * pMan, * pTemp;
+    pMan = Abc_NtkToDar( pNtk, 0, 1 );
+    if ( pMan == NULL )
+        return NULL;
+    pMan = Saig_SynchSequenceApply( pTemp = pMan, nWords, fVerbose );
+    Aig_ManStop( pTemp );
+    if ( pMan == NULL )
+        return NULL;
+    pNtkAig = Abc_NtkFromDar( pNtk, pMan );
+    Aig_ManStop( pMan );
+    return pNtkAig;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs phase abstraction.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Abc_Ntk_t * Abc_NtkDarSynch( Abc_Ntk_t * pNtk1, Abc_Ntk_t * pNtk2, int nWords, int fVerbose )
+{
+    extern Aig_Man_t * Saig_Synchronize( Aig_Man_t * pAig1, Aig_Man_t * pAig2, int nWords, int fVerbose );
+    Abc_Ntk_t * pNtkAig;
+    Aig_Man_t * pMan1, * pMan2, * pMan;
+    pMan1 = Abc_NtkToDar( pNtk1, 0, 1 );
+    if ( pMan1 == NULL )
+        return NULL;
+    pMan2 = Abc_NtkToDar( pNtk2, 0, 1 );
+    if ( pMan2 == NULL )
+    {
+        Aig_ManStop( pMan1 );
+        return NULL;
+    }
+    pMan = Saig_Synchronize( pMan1, pMan2, nWords, fVerbose );
+    Aig_ManStop( pMan1 );
+    Aig_ManStop( pMan2 );
+    if ( pMan == NULL )
+        return NULL;
+    pNtkAig = Abc_NtkFromAigPhase( pMan );
+    pNtkAig->pName = Extra_UtilStrsav("miter");
+    pNtkAig->pSpec = NULL;
+    Aig_ManStop( pMan );
+    return pNtkAig;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs phase abstraction.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
 Abc_Ntk_t * Abc_NtkDarFrames( Abc_Ntk_t * pNtk, int nPrefix, int nFrames, int fInit, int fVerbose )
 {
     Abc_Ntk_t * pNtkAig;
diff --git a/src/base/io/ioReadBlifMv.c b/src/base/io/ioReadBlifMv.c
index 52d7eb06..880c2b5f 100644
--- a/src/base/io/ioReadBlifMv.c
+++ b/src/base/io/ioReadBlifMv.c
@@ -146,7 +146,7 @@ Abc_Ntk_t * Io_ReadBlifMv( char * pFileName, int fBlifMv, int fCheck )
     // start the file reader
     p = Io_MvAlloc();
     p->fBlifMv   = fBlifMv;
-    p->fUseReset = 0;
+    p->fUseReset = 1;
     p->pFileName = pFileName;
     p->pBuffer   = Io_MvLoadFile( pFileName );
     if ( p->pBuffer == NULL )
@@ -704,7 +704,7 @@ static Abc_Lib_t * Io_MvParse( Io_MvMan_t * p )
     int i, k;
     // iterate through the models
     Vec_PtrForEachEntry( p->vModels, pMod, i )
-    {
+    { 
         // check if there any MV lines
         if ( Vec_PtrSize(pMod->vMvs) > 0 )
             Abc_NtkStartMvVars( pMod->pNtk );
diff --git a/src/bdd/parse/parseCore.c b/src/bdd/parse/parseCore.c
index 0071fb5a..88888379 100644
--- a/src/bdd/parse/parseCore.c
+++ b/src/bdd/parse/parseCore.c
@@ -362,6 +362,7 @@ DdNode * Parse_FormulaParser( FILE * pOutput, char * pFormulaInit, int nVars, in
 
         default:
             // scan the next name
+/*
             fFound = 0;
             for ( i = 0; pTemp[i] && pTemp[i] != ' ' && pTemp[i] != '\t' && pTemp[i] != '\r' && pTemp[i] != '\n'; i++ )
             {
@@ -375,13 +376,31 @@ DdNode * Parse_FormulaParser( FILE * pOutput, char * pFormulaInit, int nVars, in
                 if ( fFound )
                     break;
             }
+*/ 
+            // bug fix by SV (9/11/08)
+            fFound = 0;
+            for ( i = 0; pTemp[i] && pTemp[i] != ' ' && pTemp[i] != '\t' && pTemp[i] != '\r' && pTemp[i] != '\n' && 
+                         pTemp[i] != PARSE_SYM_AND1 && pTemp[i] != PARSE_SYM_AND2 && pTemp[i] != PARSE_SYM_XOR1 &&
+                         pTemp[i] != PARSE_SYM_XOR2 && pTemp[i] != PARSE_SYM_XOR3 && pTemp[i] != PARSE_SYM_XOR  &&
+                         pTemp[i] != PARSE_SYM_OR1  && pTemp[i] != PARSE_SYM_OR2  && pTemp[i] != PARSE_SYM_CLOSE;
+                  i++ )
+            {}
+            for ( v = 0; v < nVars; v++ ) 
+            {
+                if ( strncmp( pTemp, ppVarNames[v], i ) == 0 && strlen(ppVarNames[v]) == (unsigned)(i) )
+                {
+                    pTemp += i-1;
+                    fFound = 1;
+                    break;
+                }
+            }
+
             if ( !fFound )
             { 
                 fprintf( pOutput, "Parse_FormulaParser(): The parser cannot find var \"%s\" in the input var list.\n", pTemp ); 
                 Flag = PARSE_FLAG_ERROR; 
                 break; 
             }
-
             // assume operation AND, if vars follow one another
             if ( Flag == PARSE_FLAG_VAR )
                 Parse_StackOpPush( pStackOp, PARSE_OPER_AND );