Version abc61128

15 files changed, 550 insertions, 123 deletions

diff --git a/abc.rc b/abc.rc
index e4902714..c2549000 100644
--- a/abc.rc
+++ b/abc.rc
@@ -1,7 +1,7 @@
 # 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 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/base/abc/abc.h b/src/base/abc/abc.h
index c4c42f99..08e1323d 100644
--- a/src/base/abc/abc.h
+++ b/src/base/abc/abc.h
@@ -648,6 +648,7 @@ extern Abc_Ntk_t *        Abc_NtkDeriveFromBdd( DdManager * dd, DdNode * bFunc,
 extern Abc_Ntk_t *        Abc_NtkBddToMuxes( Abc_Ntk_t * pNtk );
 extern DdManager *        Abc_NtkBuildGlobalBdds( Abc_Ntk_t * pNtk, int fBddSizeMax, int fDropInternal, int fReorder, int fVerbose );
 extern DdManager *        Abc_NtkFreeGlobalBdds( Abc_Ntk_t * pNtk, int fFreeMan );
+extern int                Abc_NtkSizeOfGlobalBdds( Abc_Ntk_t * pNtk );
 /*=== abcNtk.c ==========================================================*/
 extern Abc_Ntk_t *        Abc_NtkAlloc( Abc_NtkType_t Type, Abc_NtkFunc_t Func, int fUseMemMan );
 extern Abc_Ntk_t *        Abc_NtkStartFrom( Abc_Ntk_t * pNtk, Abc_NtkType_t Type, Abc_NtkFunc_t Func );
diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index 9613ab40..4164f67a 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -934,8 +934,9 @@ int Abc_CommandPrintSymms( Abc_Frame_t * pAbc, int argc, char ** argv )
     int c;
     int fUseBdds;
     int fNaive;
+    int fReorder;
     int fVerbose;
-    extern void Abc_NtkSymmetries( Abc_Ntk_t * pNtk, int fUseBdds, int fNaive, int fVerbose );
+    extern void Abc_NtkSymmetries( Abc_Ntk_t * pNtk, int fUseBdds, int fNaive, int fReorder, int fVerbose );
 
     pNtk = Abc_FrameReadNtk(pAbc);
     pOut = Abc_FrameReadOut(pAbc);
@@ -944,9 +945,10 @@ int Abc_CommandPrintSymms( Abc_Frame_t * pAbc, int argc, char ** argv )
     // set defaults
     fUseBdds = 0;
     fNaive   = 0;
+    fReorder = 1;
     fVerbose = 0;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "bnvh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "bnrvh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -956,6 +958,9 @@ int Abc_CommandPrintSymms( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 'n':
             fNaive ^= 1;
             break;
+        case 'r':
+            fReorder ^= 1;
+            break;
         case 'v':
             fVerbose ^= 1;
             break;
@@ -975,19 +980,22 @@ int Abc_CommandPrintSymms( Abc_Frame_t * pAbc, int argc, char ** argv )
         fprintf( pErr, "This command works only for combinational networks.\n" );
         return 1;
     }
-    if ( !Abc_NtkIsStrash(pNtk) )
+    if ( Abc_NtkIsStrash(pNtk) )
+        Abc_NtkSymmetries( pNtk, fUseBdds, fNaive, fReorder, fVerbose );
+    else
     {
-        fprintf( pErr, "This command works only for AIGs (run \"strash\").\n" );
-        return 1;
+        pNtk = Abc_NtkStrash( pNtk, 0, 0 );
+        Abc_NtkSymmetries( pNtk, fUseBdds, fNaive, fReorder, fVerbose );
+        Abc_NtkDelete( pNtk );
     }
-    Abc_NtkSymmetries( pNtk, fUseBdds, fNaive, fVerbose );
     return 0;
 
 usage:
-    fprintf( pErr, "usage: print_symm [-nbvh]\n" );
+    fprintf( pErr, "usage: print_symm [-bnrvh]\n" );
     fprintf( pErr, "\t         computes symmetries of the PO functions\n" );
     fprintf( pErr, "\t-b     : toggle BDD-based or SAT-based computations [default = %s].\n", fUseBdds? "BDD": "SAT" );  
     fprintf( pErr, "\t-n     : enable naive BDD-based computation [default = %s].\n", fNaive? "yes": "no" );  
+    fprintf( pErr, "\t-r     : enable dynamic BDD variable reordering [default = %s].\n", fReorder? "yes": "no" );  
     fprintf( pErr, "\t-v     : enable verbose output [default = %s].\n", fVerbose? "yes": "no" );  
     fprintf( pErr, "\t-h     : print the command usage\n");
     return 1;
@@ -7082,7 +7090,7 @@ int Abc_CommandFpga( Abc_Frame_t * pAbc, int argc, char ** argv )
     fRecovery   = 1;
     fSwitching  = 0;
     fLatchPaths = 0;
-    fVerbose    = 0;
+    fVerbose    = 1;
     DelayTarget =-1;
     nLutSize    =-1;
     Extra_UtilGetoptReset();
@@ -7383,19 +7391,19 @@ int Abc_CommandIf( Abc_Frame_t * pAbc, int argc, char ** argv )
 
     // set defaults
     memset( pPars, 0, sizeof(If_Par_t) );
-    pPars->Mode        = 1;
-    pPars->nLutSize    = 4;
-//    pPars->pLutLib    = Abc_FrameReadLibLut();
-    pPars->nCutsMax    = 2;
-    pPars->fSeq        = 0;
-    pPars->fLatchPaths = 0;
-    pPars->nLatches    = 0;
-    pPars->pTimesArr   = Abc_NtkGetCiArrivalFloats(pNtk);
-    pPars->pTimesReq   = NULL;
+    pPars->Mode        =  0;
+    pPars->nLutSize    =  5;
+//    pPars->pLutLib    =  Abc_FrameReadLibLut();
+    pPars->nCutsMax    = 10;
+    pPars->fArea       =  0;
+    pPars->fFancy      =  0;
+    pPars->fLatchPaths =  0;
+    pPars->fSeq        =  0;
+    pPars->nLatches    =  0;
     pPars->DelayTarget = -1;
-    pPars->fVerbose    = 0;
+    pPars->fVerbose    =  1;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "MKCDlsvh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "MKCDaflsvh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -7443,6 +7451,12 @@ int Abc_CommandIf( Abc_Frame_t * pAbc, int argc, char ** argv )
             if ( pPars->DelayTarget <= 0.0 ) 
                 goto usage;
             break;
+        case 'a':
+            pPars->fArea ^= 1;
+            break;
+        case 'f':
+            pPars->fFancy ^= 1;
+            break;
         case 'l':
             pPars->fLatchPaths ^= 1;
             break;
@@ -7467,7 +7481,13 @@ int Abc_CommandIf( Abc_Frame_t * pAbc, int argc, char ** argv )
     if ( pPars->Mode < 0 || pPars->Mode > 4 )
     {
         fprintf( pErr, "Incorrect mapping mode.\n" );
-        return 1;
+        goto usage;
+    }
+
+    if ( pPars->nCutsMax < 2 || pPars->nCutsMax >= (1<<12) )
+    {
+        fprintf( pErr, "Incorrect number of cuts.\n" );
+        goto usage;
     }
 
     // set the latch paths
@@ -7527,7 +7547,7 @@ usage:
         sprintf( LutSize, "library" );
     else
         sprintf( LutSize, "%d", pPars->nLutSize );
-    fprintf( pErr, "usage: if [-M num] [-K num] [-C num] [-D float] [-lsvh]\n" );
+    fprintf( pErr, "usage: if [-M num] [-K num] [-C num] [-D float] [-aflsvh]\n" );
     fprintf( pErr, "\t           performs FPGA mapping of the network as follows:\n" );
     fprintf( pErr, "\t               1 - delay only\n" );
     fprintf( pErr, "\t               2 - area only\n" );
@@ -7537,6 +7557,8 @@ usage:
     fprintf( pErr, "\t-K num   : the number of LUT inputs (2 < num < 32) [default = %s]\n", LutSize );
     fprintf( pErr, "\t-C num   : the max number of cuts to use (1 < num < 2^12) [default = %d]\n", pPars->nCutsMax );
     fprintf( pErr, "\t-D float : sets the delay constraint for the mapping [default = %s]\n", Buffer );  
+    fprintf( pErr, "\t-a       : toggles area-oriented mapping [default = %s]\n", pPars->fArea? "yes": "no" );
+    fprintf( pErr, "\t-f       : toggles one fancy feature [default = %s]\n", pPars->fFancy? "yes": "no" );
     fprintf( pErr, "\t-l       : optimizes latch paths for delay, other paths for area [default = %s]\n", pPars->fLatchPaths? "yes": "no" );
     fprintf( pErr, "\t-s       : toggles sequential mapping [default = %s]\n", pPars->fSeq? "yes": "no" );
     fprintf( pErr, "\t-v       : toggles verbose output [default = %s]\n", pPars->fVerbose? "yes": "no" );
diff --git a/src/base/abci/abcIf.c b/src/base/abci/abcIf.c
index 6b3e0e7c..70971952 100644
--- a/src/base/abci/abcIf.c
+++ b/src/base/abci/abcIf.c
@@ -29,6 +29,7 @@ static If_Man_t *  Abc_NtkToIf( Abc_Ntk_t * pNtk, If_Par_t * pPars );
 static Abc_Ntk_t * Abc_NtkFromIf( If_Man_t * pIfMan, Abc_Ntk_t * pNtk );
 static Abc_Obj_t * Abc_NodeFromIf_rec( Abc_Ntk_t * pNtkNew, If_Man_t * pIfMan, If_Obj_t * pIfObj );
 static Hop_Obj_t * Abc_NodeIfToHop( Hop_Man_t * pHopMan, If_Man_t * pIfMan, If_Cut_t * pCut );
+static Hop_Obj_t * Abc_NodeIfToHop2( Hop_Man_t * pHopMan, If_Man_t * pIfMan, If_Obj_t * pIfObj );
  
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
@@ -56,6 +57,10 @@ Abc_Ntk_t * Abc_NtkIf( Abc_Ntk_t * pNtk, If_Par_t * pPars )
     if ( Abc_NtkGetChoiceNum( pNtk ) )
         printf( "Performing FPGA mapping with choices.\n" );
 
+    // get timing information
+    pPars->pTimesArr = Abc_NtkGetCiArrivalFloats(pNtk);
+    pPars->pTimesReq = NULL;
+
     // perform FPGA mapping
     pIfMan = Abc_NtkToIf( pNtk, pPars );    
     if ( pIfMan == NULL )
@@ -115,7 +120,7 @@ If_Man_t * Abc_NtkToIf( Abc_Ntk_t * pNtk, If_Par_t * pPars )
         pNode->pCopy = (Abc_Obj_t *)If_ManCreatePi( pIfMan );
 
     // load the AIG into the mapper
-    pProgress = Extra_ProgressBarStart( stdout, Abc_NtkNodeNum(pNtk) );
+    pProgress = Extra_ProgressBarStart( stdout, Abc_NtkObjNumMax(pNtk) );
     Abc_AigForEachAnd( pNtk, pNode, i )
     {
         Extra_ProgressBarUpdate( pProgress, i, NULL );
@@ -212,7 +217,8 @@ Abc_Obj_t * Abc_NodeFromIf_rec( Abc_Ntk_t * pNtkNew, If_Man_t * pIfMan, If_Obj_t
     If_CutForEachLeaf( pIfMan, pCutBest, pIfLeaf, i )
         Abc_ObjAddFanin( pNodeNew, Abc_NodeFromIf_rec(pNtkNew, pIfMan, pIfLeaf) );
     // derive the function of this node
-    pNodeNew->pData = Abc_NodeIfToHop( pNtkNew->pManFunc, pIfMan, pCutBest );
+//    pNodeNew->pData = Abc_NodeIfToHop( pNtkNew->pManFunc, pIfMan, pCutBest );
+    pNodeNew->pData = Abc_NodeIfToHop2( pNtkNew->pManFunc, pIfMan, pIfObj );
     If_ObjSetCopy( pIfObj, pNodeNew );
     return pNodeNew;
 }
@@ -280,6 +286,76 @@ Hop_Obj_t * Abc_NodeIfToHop( Hop_Man_t * pHopMan, If_Man_t * pIfMan, If_Cut_t *
     return gFunc;
 }
 
+
+/**Function*************************************************************
+
+  Synopsis    [Recursively derives the truth table for the cut.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Hop_Obj_t * Abc_NodeIfToHop2_rec( Hop_Man_t * pHopMan, If_Man_t * pIfMan, If_Obj_t * pIfObj, Vec_Ptr_t * vVisited )
+{
+    If_Cut_t * pCut;
+    Hop_Obj_t * gFunc, * gFunc0, * gFunc1;
+    // get the best cut
+    pCut = If_ObjCutTriv(pIfObj);
+    // if the cut is visited, return the result
+    if ( If_CutData(pCut) )
+        return If_CutData(pCut);
+    // compute the functions of the children
+    gFunc0 = Abc_NodeIfToHop2_rec( pHopMan, pIfMan, pIfObj->pFanin0, vVisited );
+    gFunc1 = Abc_NodeIfToHop2_rec( pHopMan, pIfMan, pIfObj->pFanin1, vVisited );
+    // get the function of the cut
+    gFunc  = Hop_And( pHopMan, Hop_NotCond(gFunc0, pIfObj->fCompl0), Hop_NotCond(gFunc1, pIfObj->fCompl1) );  
+    gFunc  = Hop_NotCond( gFunc, pCut->Phase );
+    assert( If_CutData(pCut) == NULL );
+    If_CutSetData( pCut, gFunc );
+    // add this cut to the visited list
+    Vec_PtrPush( vVisited, pCut );
+    return gFunc;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Derives the truth table for one cut.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Hop_Obj_t * Abc_NodeIfToHop2( Hop_Man_t * pHopMan, If_Man_t * pIfMan, If_Obj_t * pIfObj )
+{
+    If_Cut_t * pCut;
+    Hop_Obj_t * gFunc;
+    If_Obj_t * pLeaf;
+    int i;
+    // get the best cut
+    pCut = If_ObjCutBest(pIfObj);
+    assert( pCut->nLeaves > 1 );
+    // set the leaf variables
+    If_CutForEachLeaf( pIfMan, pCut, pLeaf, i )
+        If_CutSetData( If_ObjCutTriv(pLeaf), Hop_IthVar(pHopMan, i) );
+    // recursively compute the function while collecting visited cuts
+    Vec_PtrClear( pIfMan->vTemp );
+    gFunc = Abc_NodeIfToHop2_rec( pHopMan, pIfMan, pIfObj, pIfMan->vTemp ); 
+//    printf( "%d ", Vec_PtrSize(p->vTemp) );
+    // clean the cuts
+    If_CutForEachLeaf( pIfMan, pCut, pLeaf, i )
+        If_CutSetData( If_ObjCutTriv(pLeaf), NULL );
+    Vec_PtrForEachEntry( pIfMan->vTemp, pCut, i )
+        If_CutSetData( pCut, NULL );
+    return gFunc;
+}
+
+
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/base/abci/abcNtbdd.c b/src/base/abci/abcNtbdd.c
index bd035eb0..fd5a38e1 100644
--- a/src/base/abci/abcNtbdd.c
+++ b/src/base/abci/abcNtbdd.c
@@ -269,15 +269,16 @@ DdManager * Abc_NtkBuildGlobalBdds( Abc_Ntk_t * pNtk, int nBddSizeMax, int fDrop
     pObj = Abc_AigConst1(pNtk);
     if ( Abc_ObjFanoutNum(pObj) > 0 )
     {
-        Abc_ObjSetGlobalBdd( pObj, dd->one );
-        Cudd_Ref( dd->one );
+        bFunc = dd->one;
+        Abc_ObjSetGlobalBdd( pObj, bFunc );   Cudd_Ref( bFunc );
     }
     // set the elementary variables
     Abc_NtkForEachCi( pNtk, pObj, i )
         if ( Abc_ObjFanoutNum(pObj) > 0 )
         {
-            Abc_ObjSetGlobalBdd( pObj, dd->vars[i] );
-            Cudd_Ref( dd->vars[i] );
+            bFunc = dd->vars[i];
+//            bFunc = dd->vars[Abc_NtkCiNum(pNtk) - 1 - i];
+            Abc_ObjSetGlobalBdd( pObj, bFunc );  Cudd_Ref( bFunc );
         }
 
     // collect the global functions of the COs
@@ -462,6 +463,31 @@ DdManager * Abc_NtkFreeGlobalBdds( Abc_Ntk_t * pNtk, int fFreeMan )
 
 /**Function*************************************************************
 
+  Synopsis    [Returns the shared size of global BDDs of the COs.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NtkSizeOfGlobalBdds( Abc_Ntk_t * pNtk ) 
+{
+    Vec_Ptr_t * vFuncsGlob;
+    Abc_Obj_t * pObj;
+    int RetValue, i;
+    // complement the global functions
+    vFuncsGlob = Vec_PtrAlloc( Abc_NtkCoNum(pNtk) );
+    Abc_NtkForEachCo( pNtk, pObj, i )
+        Vec_PtrPush( vFuncsGlob, Abc_ObjGlobalBdd(pObj) );
+    RetValue = Cudd_SharingSize( (DdNode **)Vec_PtrArray(vFuncsGlob), Vec_PtrSize(vFuncsGlob) );
+    Vec_PtrFree( vFuncsGlob );
+    return RetValue;
+}
+
+/**Function*************************************************************
+
   Synopsis    [Computes the BDD of the logic cone of the node.]
 
   Description []
diff --git a/src/base/abci/abcSymm.c b/src/base/abci/abcSymm.c
index d3fcb7c9..0f76065c 100644
--- a/src/base/abci/abcSymm.c
+++ b/src/base/abci/abcSymm.c
@@ -24,7 +24,7 @@
 ///                        DECLARATIONS                              ///
 ////////////////////////////////////////////////////////////////////////
  
-static void Abc_NtkSymmetriesUsingBdds( Abc_Ntk_t * pNtk, int fNaive, int fVerbose );
+static void Abc_NtkSymmetriesUsingBdds( Abc_Ntk_t * pNtk, int fNaive, int fReorder, int fVerbose );
 static void Abc_NtkSymmetriesUsingSandS( Abc_Ntk_t * pNtk, int fVerbose );
 static void Ntk_NetworkSymmsBdd( DdManager * dd, Abc_Ntk_t * pNtk, int fNaive, int fVerbose );
 static void Ntk_NetworkSymmsPrint( Abc_Ntk_t * pNtk, Extra_SymmInfo_t * pSymms );
@@ -44,10 +44,10 @@ static void Ntk_NetworkSymmsPrint( Abc_Ntk_t * pNtk, Extra_SymmInfo_t * pSymms )
   SeeAlso     []
 
 ***********************************************************************/
-void Abc_NtkSymmetries( Abc_Ntk_t * pNtk, int fUseBdds, int fNaive, int fVerbose )
+void Abc_NtkSymmetries( Abc_Ntk_t * pNtk, int fUseBdds, int fNaive, int fReorder, int fVerbose )
 {
-    if ( fUseBdds )
-        Abc_NtkSymmetriesUsingBdds( pNtk, fNaive, fVerbose );
+    if ( fUseBdds || fNaive )
+        Abc_NtkSymmetriesUsingBdds( pNtk, fNaive, fReorder, fVerbose );
     else
         Abc_NtkSymmetriesUsingSandS( pNtk, fVerbose );
 }
@@ -81,15 +81,19 @@ void Abc_NtkSymmetriesUsingSandS( Abc_Ntk_t * pNtk, int fVerbose )
   SeeAlso     []
 
 ***********************************************************************/
-void Abc_NtkSymmetriesUsingBdds( Abc_Ntk_t * pNtk, int fNaive, int fVerbose )
+void Abc_NtkSymmetriesUsingBdds( Abc_Ntk_t * pNtk, int fNaive, int fReorder, int fVerbose )
 {
     DdManager * dd;
     int clk, clkBdd, clkSym;
+    int fGarbCollect = 1;
 
     // compute the global functions
 clk = clock();
-    dd = Abc_NtkBuildGlobalBdds( pNtk, 10000000, 1, 1, fVerbose );
+    dd = Abc_NtkBuildGlobalBdds( pNtk, 10000000, 1, fReorder, fVerbose );
+    printf( "Shared BDD size = %d nodes.\n", Abc_NtkSizeOfGlobalBdds(pNtk) ); 
     Cudd_AutodynDisable( dd );
+    if ( !fGarbCollect )
+        Cudd_DisableGarbageCollection( dd );
     Cudd_zddVarsFromBddVars( dd, 2 );
 clkBdd = clock() - clk;
     // create the collapsed network
@@ -97,11 +101,10 @@ clk = clock();
     Ntk_NetworkSymmsBdd( dd, pNtk, fNaive, fVerbose );
 clkSym = clock() - clk;
     // undo the global functions
-//    Abc_NtkFreeGlobalBdds( pNtk );
-//    Extra_StopManager( dd );
-//    pNtk->pManGlob = NULL;
     Abc_NtkFreeGlobalBdds( pNtk, 1 );
-
+printf( "Statistics of BDD-based symmetry detection:\n" );
+printf( "Algorithm = %s. Reordering = %s. Garbage collection = %s.\n", 
+       fNaive? "naive" : "fast", fReorder? "yes" : "no", fGarbCollect? "yes" : "no" );
 PRT( "Constructing BDDs", clkBdd );
 PRT( "Computing symms  ", clkSym );
 PRT( "TOTAL            ", clkBdd + clkSym );
diff --git a/src/map/fpga/fpga.c b/src/map/fpga/fpga.c
index d04c9910..d7a128b0 100644
--- a/src/map/fpga/fpga.c
+++ b/src/map/fpga/fpga.c
@@ -57,8 +57,8 @@ void Fpga_Init( Abc_Frame_t * pAbc )
 {
     // set the default library
     //Fpga_LutLib_t s_LutLib = { "lutlib", 6, {0,1,2,4,8,16,32}, {0,1,2,3,4,5,6} };
-//    Fpga_LutLib_t s_LutLib = { "lutlib", 5, {0,1,1,1,1,1}, {0,1,1,1,1,1} };
-    Fpga_LutLib_t s_LutLib = { "lutlib", 4, {0,1,1,1,1}, {0,1,1,1,1} };
+    Fpga_LutLib_t s_LutLib = { "lutlib", 5, {0,1,1,1,1,1}, {0,1,1,1,1,1} };
+//    Fpga_LutLib_t s_LutLib = { "lutlib", 4, {0,1,1,1,1}, {0,1,1,1,1} };
     //Fpga_LutLib_t s_LutLib = { "lutlib", 3, {0,1,1,1}, {0,1,1,1} };
 
     Abc_FrameSetLibLut( Fpga_LutLibDup(&s_LutLib) );
diff --git a/src/map/fpga/fpgaCore.c b/src/map/fpga/fpgaCore.c
index 56facf20..634a8eb1 100644
--- a/src/map/fpga/fpgaCore.c
+++ b/src/map/fpga/fpgaCore.c
@@ -79,8 +79,12 @@ int Fpga_Mapping( Fpga_Man_t * p )
 
     // print the AI-graph used for mapping
     //Fpga_ManShow( p, "test" );
+//    if ( p->fVerbose )
+//        Fpga_MappingPrintOutputArrivals( p );
     if ( p->fVerbose )
-        Fpga_MappingPrintOutputArrivals( p );
+    {
+        PRT( "Total time", clock() - clkTotal );
+    }
     return 1;
 }
 
@@ -101,14 +105,14 @@ int Fpga_Mapping( Fpga_Man_t * p )
 ***********************************************************************/
 int Fpga_MappingPostProcess( Fpga_Man_t * p )
 {
-    int fShowSwitching    = 1;
+    int fShowSwitching    = 0;
     int fRecoverAreaFlow  = 1;
     int fRecoverArea      = 1;
     float aAreaTotalCur, aAreaTotalCur2;
     int Iter, clk;
 
-if ( p->fVerbose )
-    printf( "Best clock period = %5.2f\n", Fpga_TimeComputeArrivalMax(p) );
+//if ( p->fVerbose )
+//    printf( "Best clock period = %5.2f\n", Fpga_TimeComputeArrivalMax(p) );
 
     // compute area, set references, and collect nodes used in the mapping
     Iter = 1;
@@ -118,6 +122,9 @@ if ( p->fVerbose )
 printf( "Iteration %dD :  Area = %8.1f  ", Iter++, aAreaTotalCur );
 if ( fShowSwitching )
 printf( "Switch = %8.1f  ", Fpga_MappingGetSwitching(p,p->vMapping) );
+else
+printf( "Delay = %5.2f  ", Fpga_TimeComputeArrivalMax(p) );
+
 PRT( "Time", p->timeMatch );
 }
 
@@ -141,6 +148,8 @@ if ( p->fVerbose )
 printf( "Iteration %dF :  Area = %8.1f  ", Iter++, aAreaTotalCur );
 if ( fShowSwitching )
 printf( "Switch = %8.1f  ", Fpga_MappingGetSwitching(p,p->vMapping) );
+else
+printf( "Delay = %5.2f  ", Fpga_TimeComputeArrivalMax(p) );
 PRT( "Time", clock() - clk );
 }
     }
@@ -166,6 +175,8 @@ if ( p->fVerbose )
 printf( "Iteration %d%s :  Area = %8.1f  ", Iter++, (p->fSwitching?"S":"A"), aAreaTotalCur );
 if ( fShowSwitching )
 printf( "Switch = %8.1f  ", Fpga_MappingGetSwitching(p,p->vMapping) );
+else
+printf( "Delay = %5.2f  ", Fpga_TimeComputeArrivalMax(p) );
 PRT( "Time", clock() - clk );
 }
     }
diff --git a/src/map/fpga/fpgaCut.c b/src/map/fpga/fpgaCut.c
index c2aba4a3..a5505e72 100644
--- a/src/map/fpga/fpgaCut.c
+++ b/src/map/fpga/fpgaCut.c
@@ -130,6 +130,7 @@ void Fpga_MappingCuts( Fpga_Man_t * p )
     Fpga_CutTable_t * pTable;
     Fpga_Node_t * pNode;
     int nCuts, nNodes, i;
+    int clk = clock();
 
     // set the elementary cuts for the PI variables
     assert( p->nVarsMax > 1 && p->nVarsMax < 11 );
@@ -154,8 +155,9 @@ void Fpga_MappingCuts( Fpga_Man_t * p )
     if ( p->fVerbose )
     {
         nCuts = Fpga_CutCountAll(p);
-        printf( "Nodes = %6d. Total %d-feasible cuts = %d. Cuts per node = %.1f.\n", 
+        printf( "Nodes = %6d. Total %d-cuts = %d. Cuts per node = %.1f. ", 
                p->nNodes, p->nVarsMax, nCuts, ((float)nCuts)/p->nNodes );
+        PRT( "Time", clock() - clk );
     }
 
     // print the cuts for the first primary output
diff --git a/src/map/fpga/fpgaMatch.c b/src/map/fpga/fpgaMatch.c
index 736d38b2..d413a067 100644
--- a/src/map/fpga/fpgaMatch.c
+++ b/src/map/fpga/fpgaMatch.c
@@ -87,6 +87,18 @@ int Fpga_MappingMatches( Fpga_Man_t * p, int fDelayOriented )
         Extra_ProgressBarUpdate( pProgress, i, "Matches ..." );
     }
     Extra_ProgressBarStop( pProgress );
+/*
+    if ( !fDelayOriented )
+    {
+        float Area = 0.0;
+        for ( i = 0; i < p->nOutputs; i++ )
+        {
+            printf( "%5.2f ", Fpga_Regular(p->pOutputs[i])->pCutBest->aFlow );
+            Area += Fpga_Regular(p->pOutputs[i])->pCutBest->aFlow;
+        }
+        printf( "\nTotal = %5.2f\n", Area );
+    }
+*/
     return 1;
 }
 
diff --git a/src/map/if/if.h b/src/map/if/if.h
index 04e1541e..a1d2d41b 100644
--- a/src/map/if/if.h
+++ b/src/map/if/if.h
@@ -75,8 +75,10 @@ struct If_Par_t_
     If_Lib_t *         pLutLib;       // the LUT library
     int                nCutsMax;      // the max number of cuts
     int                fVerbose;      // the verbosity flag
-    int                fSeq;          // sequential mapping
+    int                fArea;         // area-oriented mapping
+    int                fFancy;        // a fancy feature
     int                fLatchPaths;   // reset timing on latch paths
+    int                fSeq;          // sequential mapping
     int                nLatches;      // the number of latches
     float              DelayTarget;   // delay target
     float *            pTimesArr;     // arrival times
@@ -110,6 +112,9 @@ struct If_Man_t_
     float              fEpsilon;      // epsilon used for comparison
     float              RequiredGlo;   // global required times
     float              AreaGlo;       // global area
+    int                nCutsUsed;     // the number of cuts currently used
+    int                nCutsMerged;   // the total number of cuts merged
+    int                nCutsMax;      // the maximum number of cuts at a node
     // memory management
     Mem_Fixed_t *      pMem;          // memory manager
     int                nEntrySize;    // the size of the entry
@@ -123,7 +128,6 @@ struct If_Man_t_
 struct If_Cut_t_
 {
     float              Delay;         // the delay of the cut
-    float              Flow;          // the area flow of the cut
     float              Area;          // the area of the cut
     If_Cut_t *         pOne;          // the parent cut
     If_Cut_t *         pTwo;          // the parent cut
@@ -162,6 +166,10 @@ static inline If_Obj_t * If_ManPo( If_Man_t * p, int i )                     { r
 static inline If_Obj_t * If_ManObj( If_Man_t * p, int i )                    { return (If_Obj_t *)Vec_PtrEntry( p->vObjs, i ); }
 static inline If_Cut_t * If_ManCut( If_Man_t * p, int i )                    { return p->ppCuts[i];                            }
 
+static inline int        If_ManPiNum( If_Man_t * p )                         { return p->nObjs[IF_PI];               }
+static inline int        If_ManPoNum( If_Man_t * p )                         { return p->nObjs[IF_PO];               }
+static inline int        If_ManAndNum( If_Man_t * p )                        { return p->nObjs[IF_AND];              }
+
 static inline int        If_ObjIsConst1( If_Obj_t * pObj )                   { return pObj->Type == IF_CONST1;       }
 static inline int        If_ObjIsPi( If_Obj_t * pObj )                       { return pObj->Type == IF_PI;           }
 static inline int        If_ObjIsPo( If_Obj_t * pObj )                       { return pObj->Type == IF_PO;           }
@@ -229,6 +237,8 @@ static inline float      If_CutLutArea( If_Man_t * p, If_Cut_t * pCut )      { r
 ///                    FUNCTION DECLARATIONS                         ///
 ////////////////////////////////////////////////////////////////////////
 
+/*=== ifCore.c ==========================================================*/
+extern int             If_ManPerformMapping( If_Man_t * p );
 /*=== ifMan.c ==========================================================*/
 extern If_Man_t *      If_ManStart( If_Par_t * pPars );
 extern void            If_ManStop( If_Man_t * p );
@@ -236,11 +246,12 @@ extern If_Obj_t *      If_ManCreatePi( If_Man_t * p );
 extern If_Obj_t *      If_ManCreatePo( If_Man_t * p, If_Obj_t * pDriver, int fCompl0 );
 extern If_Obj_t *      If_ManCreateAnd( If_Man_t * p, If_Obj_t * pFan0, int fCompl0, If_Obj_t * pFan1, int fCompl1 );
 /*=== ifMap.c ==========================================================*/
-extern int             If_ManPerformMapping( If_Man_t * p );
+extern void            If_ObjPerformMapping( If_Man_t * p, If_Obj_t * pObj, int Mode );
 /*=== ifUtil.c ==========================================================*/
 extern float           If_ManDelayMax( If_Man_t * p );
 extern void            If_ManCleanNodeCopy( If_Man_t * p );
 extern void            If_ManCleanCutData( If_Man_t * p );
+extern void            If_ManComputeRequired( If_Man_t * p, int fFirstTime );
 extern float           If_ManScanMapping( If_Man_t * p );
 
 #ifdef __cplusplus
diff --git a/src/map/if/ifCore.c b/src/map/if/ifCore.c
index 4d7e92d0..37a22d8b 100644
--- a/src/map/if/ifCore.c
+++ b/src/map/if/ifCore.c
@@ -24,6 +24,8 @@
 ///                        DECLARATIONS                              ///
 ////////////////////////////////////////////////////////////////////////
 
+static int If_ManPerformMappingRound( If_Man_t * p, int nCutsUsed, int Mode );
+
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////
@@ -39,6 +41,72 @@
   SeeAlso     []
 
 ***********************************************************************/
+int If_ManPerformMapping( If_Man_t * p )
+{
+    If_Obj_t * pObj;
+    int nItersFlow = 2;
+    int nItersArea = 1;
+    int clkTotal = clock();
+    int i;
+    // set arrival times and trivial cuts at const 1 and PIs
+    If_ManConst1(p)->Cuts[0].Delay = 0.0;
+    If_ManForEachPi( p, pObj, i )
+        pObj->Cuts[0].Delay = p->pPars->pTimesArr[i];
+    // set the fanout estimates of the PIs
+    If_ManForEachPi( p, pObj, i )
+        pObj->EstRefs = (float)1.0;
+    // delay oriented mapping
+    If_ManPerformMappingRound( p, p->pPars->nCutsMax, 0 );
+    // area flow oriented mapping
+    for ( i = 0; i < nItersFlow; i++ )
+        If_ManPerformMappingRound( p, p->pPars->nCutsMax, 1 );
+    // area oriented mapping
+    for ( i = 0; i < nItersArea; i++ )
+        If_ManPerformMappingRound( p, p->pPars->nCutsMax, 2 );
+    if ( p->pPars->fVerbose )
+    {
+        PRT( "Total time", clock() - clkTotal );
+    }
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int If_ManPerformMappingRound( If_Man_t * p, int nCutsUsed, int Mode )
+{
+    If_Obj_t * pObj;
+    int i, clk = clock();
+    assert( Mode >= 0 && Mode <= 2 );
+    // set the cut number
+    p->nCutsUsed   = nCutsUsed;
+    p->nCutsMerged = 0;
+    p->nCutsMax    = 0;
+    // map the internal nodes
+    If_ManForEachNode( p, pObj, i )
+        If_ObjPerformMapping( p, pObj, Mode );
+    // compute required times and stats
+    If_ManComputeRequired( p, Mode==0 );
+    if ( p->pPars->fVerbose )
+    {
+        char Symb = (Mode == 0)? 'D' : ((Mode == 1)? 'F' : 'A');
+        printf( "%c:  Del = %6.2f. Area = %8.2f. Cuts = %6d. Lim = %2d. Ave = %5.2f. ", 
+            Symb, p->RequiredGlo, p->AreaGlo, p->nCutsMerged, p->nCutsUsed, 1.0 * p->nCutsMerged / If_ManAndNum(p) );
+        PRT( "T", clock() - clk );
+//    printf( "Max number of cuts = %d. Average number of cuts = %5.2f.\n", 
+//        p->nCutsMax, 1.0 * p->nCutsMerged / If_ManAndNum(p) );
+    }
+    return 1;
+}
+
 
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
diff --git a/src/map/if/ifMan.c b/src/map/if/ifMan.c
index 616c5cf6..bc13c6f0 100644
--- a/src/map/if/ifMan.c
+++ b/src/map/if/ifMan.c
@@ -97,7 +97,7 @@ void If_ManStop( If_Man_t * p )
         FREE( p->pPars->pTimesReq );
     // free temporary cut memory
     pTemp = p->ppCuts[0];
-    for ( i = 1; i < p->pPars->nCutsMax * p->pPars->nCutsMax; i++ )
+    for ( i = 1; i < 1 + p->pPars->nCutsMax * p->pPars->nCutsMax; i++ )
         if ( pTemp > p->ppCuts[i] )
             pTemp = p->ppCuts[i];
     free( pTemp );
@@ -228,14 +228,18 @@ If_Cut_t ** If_ManSetupCuts( If_Man_t * p )
 {
     If_Cut_t ** pCutStore;
     int * pArrays, nCutSize, nCutsTotal, i;
-    nCutsTotal = p->pPars->nCutsMax * p->pPars->nCutsMax;
+    // decide how many cuts to alloc
+    nCutsTotal = 1 + p->pPars->nCutsMax * p->pPars->nCutsMax;
+    // figure out the cut size
     nCutSize = sizeof(If_Cut_t) + sizeof(int) * p->pPars->nLutSize;
+    // allocate and clean space for cuts
     pCutStore = (If_Cut_t **)ALLOC( If_Cut_t *, (nCutsTotal + 1) );
     memset( pCutStore, 0, sizeof(If_Cut_t *) * (nCutsTotal + 1) );
     pCutStore[0] = (If_Cut_t *)ALLOC( char, nCutSize * nCutsTotal );
     memset( pCutStore[0], 0, nCutSize * nCutsTotal );
     for ( i = 1; i < nCutsTotal; i++ )
         pCutStore[i] = (If_Cut_t *)((char *)pCutStore[0] + sizeof(If_Cut_t) * i);
+    // assign room for cut leaves
     pArrays = (int *)((char *)pCutStore[0] + sizeof(If_Cut_t) * nCutsTotal);
     for ( i = 0; i < nCutsTotal; i++ )
         pCutStore[i]->pLeaves = pArrays + i * p->pPars->nLutSize;
diff --git a/src/map/if/ifMap.c b/src/map/if/ifMap.c
index 5f2c4133..0b505062 100644
--- a/src/map/if/ifMap.c
+++ b/src/map/if/ifMap.c
@@ -24,13 +24,69 @@
 ///                        DECLARATIONS                              ///
 ////////////////////////////////////////////////////////////////////////
 
+/*
+  Ideas to try:
+  - reverse order of area recovery
+  - ordering of the outputs by size
+  - merging Delay, Delay2, and Area
+  - expand/reduce area recovery
+
+*/
+
 ////////////////////////////////////////////////////////////////////////
 ///                     FUNCTION DEFINITIONS                         ///
 ////////////////////////////////////////////////////////////////////////
 
 /**Function*************************************************************
 
-  Synopsis    [Prepares the object for FPGA mapping.]
+  Synopsis    [Returns 1 if pDom is contained in pCut.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline int If_CutCheckDominance( If_Cut_t * pDom, If_Cut_t * pCut )
+{
+    int i, k;
+    for ( i = 0; i < (int)pDom->nLeaves; i++ )
+    {
+        for ( k = 0; k < (int)pCut->nLeaves; k++ )
+            if ( pDom->pLeaves[i] == pCut->pLeaves[k] )
+                break;
+        if ( k == (int)pCut->nLeaves ) // node i in pDom is not contained in pCut
+            return 0;
+    }
+    // every node in pDom is contained in pCut
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if pDom is equal to pCut.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline int If_CutCheckEquality( If_Cut_t * pDom, If_Cut_t * pCut )
+{
+    int i;
+    if ( (int)pDom->nLeaves != (int)pCut->nLeaves )
+        return 0;
+    for ( i = 0; i < (int)pDom->nLeaves; i++ )
+        if ( pDom->pLeaves[i] != pCut->pLeaves[i] )
+            return 0;
+    return 1;
+}
+/**Function*************************************************************
+
+  Synopsis    [Returns 1 if the cut is contained.]
 
   Description []
                
@@ -39,8 +95,39 @@
   SeeAlso     []
 
 ***********************************************************************/
-int If_CutMerge( If_Cut_t * pC0, If_Cut_t * pC1, If_Cut_t * pC, int nLimit )
+int If_CutFilter( If_Man_t * p, If_Cut_t * pCut )
 {
+    If_Cut_t * pTemp;
+    int i;
+    for ( i = 0; i < p->nCuts; i++ )
+    {
+        pTemp = p->ppCuts[i];
+        if ( pTemp->nLeaves > pCut->nLeaves )
+            continue;
+        // skip the non-contained cuts
+//        if ( (pTemp->uSign & pCut->uSign) != pTemp->uSign )
+//            continue;
+        // check containment seriously
+        if ( If_CutCheckDominance( pTemp, pCut ) )
+//        if ( If_CutCheckEquality( pTemp, pCut ) )
+            return 1;
+    }
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares the object for FPGA mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int If_CutMergeOrdered( If_Cut_t * pC0, If_Cut_t * pC1, If_Cut_t * pC, int nLimit )
+{ 
     int i, k, c;
     assert( pC0->nLeaves >= pC1->nLeaves );
     // the case of the largest cut sizes
@@ -125,6 +212,33 @@ int If_CutMerge( If_Cut_t * pC0, If_Cut_t * pC1, If_Cut_t * pC, int nLimit )
   SeeAlso     []
 
 ***********************************************************************/
+static inline int If_CutMerge( If_Cut_t * pCut0, If_Cut_t * pCut1, If_Cut_t * pCut, int nLimit )
+{ 
+    // merge the nodes
+    if ( pCut0->nLeaves < pCut1->nLeaves )
+    {
+        if ( !If_CutMergeOrdered( pCut1, pCut0, pCut, nLimit ) )
+            return 0;
+    }
+    else
+    {
+        if ( !If_CutMergeOrdered( pCut0, pCut1, pCut, nLimit ) )
+            return 0;
+    }
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares the object for FPGA mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
 int If_CutCompareDelay( If_Cut_t ** ppC0, If_Cut_t ** ppC1 )
 {
     If_Cut_t * pC0 = *ppC0;
@@ -137,9 +251,39 @@ int If_CutCompareDelay( If_Cut_t ** ppC0, If_Cut_t ** ppC1 )
         return -1;
     if ( pC0->nLeaves > pC1->nLeaves )
         return 1;
-    if ( pC0->Flow < pC1->Flow )
+    if ( pC0->Area < pC1->Area )
         return -1;
-    if ( pC0->Flow > pC1->Flow )
+    if ( pC0->Area > pC1->Area )
+        return 1;
+    return 0;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Prepares the object for FPGA mapping.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int If_CutCompareDelayOld( If_Cut_t ** ppC0, If_Cut_t ** ppC1 )
+{
+    If_Cut_t * pC0 = *ppC0;
+    If_Cut_t * pC1 = *ppC1;
+    if ( pC0->Delay < pC1->Delay )
+        return -1;
+    if ( pC0->Delay > pC1->Delay )
+        return 1;
+    if ( pC0->Area < pC1->Area )
+        return -1;
+    if ( pC0->Area > pC1->Area )
+        return 1;
+    if ( pC0->nLeaves < pC1->nLeaves )
+        return -1;
+    if ( pC0->nLeaves > pC1->nLeaves )
         return 1;
     return 0;
 }
@@ -159,9 +303,9 @@ int If_CutCompareArea( If_Cut_t ** ppC0, If_Cut_t ** ppC1 )
 {
     If_Cut_t * pC0 = *ppC0;
     If_Cut_t * pC1 = *ppC1;
-    if ( pC0->Flow < pC1->Flow )
+    if ( pC0->Area < pC1->Area )
         return -1;
-    if ( pC0->Flow > pC1->Flow )
+    if ( pC0->Area > pC1->Area )
         return 1;
     if ( pC0->nLeaves < pC1->nLeaves )
         return -1;
@@ -176,6 +320,28 @@ int If_CutCompareArea( If_Cut_t ** ppC0, If_Cut_t ** ppC1 )
 
 /**Function*************************************************************
 
+  Synopsis    [Sorts the cuts.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void If_ManSortCuts( If_Man_t * p, int Mode )
+{
+    // sort the cuts
+    if ( Mode || p->pPars->fArea ) // area
+        qsort( p->ppCuts, p->nCuts, sizeof(If_Cut_t *), (int (*)(const void *, const void *))If_CutCompareArea );
+    else if ( p->pPars->fFancy )
+        qsort( p->ppCuts, p->nCuts, sizeof(If_Cut_t *), (int (*)(const void *, const void *))If_CutCompareDelayOld );
+    else
+        qsort( p->ppCuts, p->nCuts, sizeof(If_Cut_t *), (int (*)(const void *, const void *))If_CutCompareDelay );
+}
+
+/**Function*************************************************************
+
   Synopsis    [Computes delay.]
 
   Description []
@@ -190,6 +356,7 @@ float If_CutDelay( If_Man_t * p, If_Cut_t * pCut )
     If_Obj_t * pLeaf;
     float Delay;
     int i;
+    assert( pCut->nLeaves > 1 );
     Delay = -IF_FLOAT_LARGE;
     If_CutForEachLeaf( p, pCut, pLeaf, i )
         Delay = IF_MAX( Delay, If_ObjCutBest(pLeaf)->Delay );
@@ -212,9 +379,18 @@ float If_CutFlow( If_Man_t * p, If_Cut_t * pCut )
     If_Obj_t * pLeaf;
     float Flow;
     int i;
+    assert( pCut->nLeaves > 1 );
     Flow = If_CutLutArea(p, pCut);
     If_CutForEachLeaf( p, pCut, pLeaf, i )
-        Flow += If_ObjCutBest(pLeaf)->Flow / pLeaf->EstRefs;
+    {
+        if ( pLeaf->nRefs == 0 )
+            Flow += If_ObjCutBest(pLeaf)->Area;
+        else
+        {
+            assert( pLeaf->EstRefs > p->fEpsilon );
+            Flow += If_ObjCutBest(pLeaf)->Area / pLeaf->EstRefs;
+        }
+    }
     return Flow;
 }
 
@@ -229,15 +405,19 @@ float If_CutFlow( If_Man_t * p, If_Cut_t * pCut )
   SeeAlso     []
 
 ***********************************************************************/
-float If_CutArea1( If_Man_t * p, If_Cut_t * pCut )
+float If_CutRef( If_Man_t * p, If_Cut_t * pCut, int nLevels )
 {
     If_Obj_t * pLeaf;
     float Area;
     int i;
     Area = If_CutLutArea(p, pCut);
     If_CutForEachLeaf( p, pCut, pLeaf, i )
-        if ( pLeaf->nRefs == 0 )
-            Area += If_CutLutArea(p, If_ObjCutBest(pLeaf));
+    {
+        assert( pLeaf->nRefs >= 0 );
+        if ( pLeaf->nRefs++ > 0 || !If_ObjIsAnd(pLeaf) || nLevels == 1 )
+            continue;
+        Area += If_CutRef( p, If_ObjCutBest(pLeaf), nLevels - 1 );
+    }
     return Area;
 }
 
@@ -252,12 +432,20 @@ float If_CutArea1( If_Man_t * p, If_Cut_t * pCut )
   SeeAlso     []
 
 ***********************************************************************/
-void If_CutRef1( If_Man_t * p, If_Cut_t * pCut )
+float If_CutDeref( If_Man_t * p, If_Cut_t * pCut, int nLevels )
 {
     If_Obj_t * pLeaf;
+    float Area;
     int i;
+    Area = If_CutLutArea(p, pCut);
     If_CutForEachLeaf( p, pCut, pLeaf, i )
-        pLeaf->nRefs++;
+    {
+        assert( pLeaf->nRefs > 0 );
+        if ( --pLeaf->nRefs > 0 || !If_ObjIsAnd(pLeaf) || nLevels == 1 )
+            continue;
+        Area += If_CutDeref( p, If_ObjCutBest(pLeaf), nLevels - 1 );
+    }
+    return Area;
 }
 
 /**Function*************************************************************
@@ -271,12 +459,14 @@ void If_CutRef1( If_Man_t * p, If_Cut_t * pCut )
   SeeAlso     []
 
 ***********************************************************************/
-void If_CutDeref1( If_Man_t * p, If_Cut_t * pCut )
+float If_CutArea( If_Man_t * p, If_Cut_t * pCut, int nLevels )
 {
-    If_Obj_t * pLeaf;
-    int i;
-    If_CutForEachLeaf( p, pCut, pLeaf, i )
-        pLeaf->nRefs--;
+    float aResult, aResult2;
+    assert( pCut->nLeaves > 1 );
+    aResult2 = If_CutRef( p, pCut, nLevels );
+    aResult  = If_CutDeref( p, pCut, nLevels );
+    assert( aResult == aResult2 );
+    return aResult;
 }
 
 /**Function*************************************************************
@@ -303,85 +493,85 @@ void If_CutCopy( If_Cut_t * pCutDest, If_Cut_t * pCutSrc )
 
   Synopsis    [Finds the best cut.]
 
-  Description []
+  Description [Mapping modes: delay (0), area flow (1), area (2).]
                
   SideEffects []
 
   SeeAlso     []
 
 ***********************************************************************/
-void If_ObjPerformMapping( If_Man_t * p, If_Obj_t * pObj )
+void If_ObjPerformMapping( If_Man_t * p, If_Obj_t * pObj, int Mode )
 {
     If_Cut_t * pCut0, * pCut1, * pCut;
     int i, k;
-    // create cross-product of the cuts
+
+    // prepare
+    if ( Mode == 0 )
+        pObj->EstRefs = (float)pObj->nRefs;
+    else if ( Mode == 1 )
+        pObj->EstRefs = (float)((2.0 * pObj->EstRefs + pObj->nRefs) / 3.0);
+    else if ( Mode == 2 && pObj->nRefs > 0 )
+        If_CutDeref( p, If_ObjCutBest(pObj), 100 );
+
+    // recompute the parameters of the best cut
     p->nCuts = 0;
-    pCut = p->ppCuts[0];
+    p->nCutsMerged++;
+    if ( Mode )
+    {
+        pCut = If_ObjCutBest(pObj);
+        pCut->Delay = If_CutDelay( p, pCut );
+        assert( pCut->Delay <= pObj->Required + p->fEpsilon );
+        pCut->Area  = (Mode == 2)? If_CutArea( p, pCut, 100 ) : If_CutFlow( p, pCut );
+        // save the best cut from the previous iteration
+        If_CutCopy( p->ppCuts[p->nCuts++], pCut );
+        p->nCutsMerged++;
+    }
+
+    // generate cuts
+    pCut = p->ppCuts[p->nCuts];
     If_ObjForEachCut( pObj->pFanin0, pCut0, i )
     If_ObjForEachCut( pObj->pFanin1, pCut1, k )
     {
-        if ( pCut0->nLeaves < pCut1->nLeaves )
-        {
-            if ( !If_CutMerge( pCut1, pCut0, pCut, p->pPars->nLutSize ) )
-                continue;
-        }
-        else
-        {
-            if ( !If_CutMerge( pCut0, pCut1, pCut, p->pPars->nLutSize ) )
-                continue;
-        }
+        // prefilter using arrival times
+        if ( Mode && (pCut0->Delay > pObj->Required + p->fEpsilon || pCut1->Delay > pObj->Required + p->fEpsilon) )
+            continue;
+        // merge the nodes
+        if ( !If_CutMerge( pCut0, pCut1, pCut, p->pPars->nLutSize ) )
+            continue;
+        // check if this cut is contained in any of the available cuts
+        if ( If_CutFilter( p, pCut ) )
+            continue;
+        // check if the cut satisfies the required times
+        pCut->Delay = If_CutDelay( p, pCut );
+        if ( Mode && pCut->Delay > pObj->Required + p->fEpsilon )
+            continue;
         // the cuts have been successfully merged
         pCut->pOne = pCut0; pCut->fCompl0 = pObj->fCompl0;
         pCut->pTwo = pCut1; pCut->fCompl1 = pObj->fCompl1;
 //        pCut->Phase = ...
-        pCut->Delay = If_CutDelay( p, pCut );
-        pCut->Flow  = If_CutFlow( p, pCut );
+        pCut->Area  = (Mode == 2)? If_CutArea( p, pCut, 100 ) : If_CutFlow( p, pCut );
+        p->nCutsMerged++;
         // prepare room for the next cut
         pCut = p->ppCuts[++p->nCuts];
     } 
-    // sort the cuts
-    if ( p->pPars->Mode == 1 ) // delay
-        qsort( p->ppCuts, p->nCuts, sizeof(If_Cut_t *), (int (*)(const void *, const void *))If_CutCompareDelay );
-    else
-        qsort( p->ppCuts, p->nCuts, sizeof(If_Cut_t *), (int (*)(const void *, const void *))If_CutCompareArea );
+    assert( p->nCuts > 0 );
+    If_ManSortCuts( p, Mode );
     // take the first
-    pObj->nCuts = IF_MIN( p->nCuts + 1, p->pPars->nCutsMax );
+    pObj->nCuts = IF_MIN( p->nCuts + 1, p->nCutsUsed );
     If_ObjForEachCutStart( pObj, pCut, i, 1 )
         If_CutCopy( pCut, p->ppCuts[i-1] );
     pObj->iCut = 1;
-}
-
-/**Function*************************************************************
-
-  Synopsis    [Maps the nodes for delay.]
-
-  Description []
-               
-  SideEffects []
-
-  SeeAlso     []
-
-***********************************************************************/
-int If_ManPerformMapping( If_Man_t * p )
-{
-    If_Obj_t * pObj;
-    float DelayBest;
-    int i, clk = clock();
-    // set arrival times and trivial cuts at const 1 and PIs
-    If_ManConst1(p)->Cuts[0].Delay = 0.0;
-    If_ManForEachPi( p, pObj, i )
-        pObj->Cuts[0].Delay = p->pPars->pTimesArr[i];
-    // set the initial fanout estimates
-    If_ManForEachObj( p, pObj, i )
-        pObj->EstRefs = (float)pObj->nRefs;
-    // map the internal nodes
-    If_ManForEachNode( p, pObj, i )
-        If_ObjPerformMapping( p, pObj );
-    // get the best arrival time of the POs
-    DelayBest = If_ManDelayMax(p);
-    printf( "Best delay = %d. ", (int)DelayBest );
-    PRT( "Time", clock() - clk );
-    return 1;
+    assert( If_ObjCutBest(pObj)->nLeaves > 1 );
+    // assign delay of the trivial cut
+    If_ObjCutTriv(pObj)->Delay = If_ObjCutBest(pObj)->Delay;
+//printf( "%d %d   ", pObj->Id, (int)If_ObjCutBest(pObj)->Delay );
+//printf( "%d %d   ", pObj->Id, pObj->nCuts );
+    // ref the selected cut
+    if ( Mode == 2 && pObj->nRefs > 0 )
+        If_CutRef( p, If_ObjCutBest(pObj), 100 );
+    // find the largest cut
+    if ( p->nCutsMax < pObj->nCuts )
+        p->nCutsMax = pObj->nCuts;
 }
 
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/map/mapper/mapperCut.c b/src/map/mapper/mapperCut.c
index 9dad07d0..91ef6562 100644
--- a/src/map/mapper/mapperCut.c
+++ b/src/map/mapper/mapperCut.c
@@ -612,7 +612,8 @@ int Map_CutMergeTwo( Map_Cut_t * pCut1, Map_Cut_t * pCut2, Map_Node_t * ppNodes[
     {
         min = i;
         for ( k = i+1; k < nTotal; k++ )
-            if ( ppNodes[k] < ppNodes[min] )
+//            if ( ppNodes[k] < ppNodes[min] ) // reported bug fix (non-determinism!)
+            if ( ppNodes[k]->Num < ppNodes[min]->Num )
                 min = k;
         pNodeTemp    = ppNodes[i];
         ppNodes[i]   = ppNodes[min];