path: root/src/aig/ivy/ivyCut.c

/**CFile****************************************************************

  FileName    [ivyCut.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [And-Inverter Graph package.]

  Synopsis    [Computes reconvergence driven sequential cut.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - May 11, 2006.]

  Revision    [$Id: ivyCut.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]

***********************************************************************/

#include "ivy.h"

////////////////////////////////////////////////////////////////////////
///                        DECLARATIONS                              ///
////////////////////////////////////////////////////////////////////////

static inline int Ivy_NodeCutHashValue( int NodeId )  { return 1 << (NodeId % 31); }

////////////////////////////////////////////////////////////////////////
///                     FUNCTION DEFINITIONS                         ///
////////////////////////////////////////////////////////////////////////

/**Function*************************************************************

  Synopsis    [Evaluate the cost of removing the node from the set of leaves.]

  Description [Returns the number of new leaves that will be brought in.
  Returns large number if the node cannot be removed from the set of leaves.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Ivy_NodeGetLeafCostOne( Ivy_Man_t * p, int Leaf, Vec_Int_t * vInside )
{
    Ivy_Obj_t * pNode;
    int nLatches, FaninLeaf, Cost;
    // make sure leaf is not a contant node
    assert( Leaf > 0 ); 
    // get the node
    pNode = Ivy_ManObj( p, Ivy_LeafId(Leaf) );
    // cannot expand over the PI node
    if ( Ivy_ObjIsPi(pNode) || Ivy_ObjIsConst1(pNode) )
        return 999;
    // get the number of latches
    nLatches = Ivy_LeafLat(Leaf) + Ivy_ObjIsLatch(pNode);
    if ( nLatches > 15 )
        return 999;
    // get the first fanin
    FaninLeaf = Ivy_LeafCreate( Ivy_ObjFaninId0(pNode), nLatches );
    Cost = FaninLeaf && (Vec_IntFind(vInside, FaninLeaf) == -1);
    // quit if this is the one fanin node
    if ( Ivy_ObjIsLatch(pNode) || Ivy_ObjIsBuf(pNode) )
        return Cost;
    assert( Ivy_ObjIsNode(pNode) );
    // get the second fanin
    FaninLeaf = Ivy_LeafCreate( Ivy_ObjFaninId1(pNode), nLatches );
    Cost += FaninLeaf && (Vec_IntFind(vInside, FaninLeaf) == -1);
    return Cost;
}

/**Function*************************************************************

  Synopsis    [Builds reconvergence-driven cut by changing one leaf at a time.]

  Description [This procedure looks at the current leaves and tries to change 
  one leaf at a time in such a way that the cut grows as little as possible.
  In evaluating the fanins, this procedure looks only at their immediate 
  predecessors (this is why it is called a one-level construction procedure).]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_ManSeqFindCut_int( Ivy_Man_t * p, Vec_Int_t * vFront, Vec_Int_t * vInside, int nSizeLimit )
{
    Ivy_Obj_t * pNode;
    int CostBest, CostCur, Leaf, LeafBest, Next, nLatches, i;
    int LeavesBest[10];
    int Counter;

    // add random selection of the best fanin!!!

    // find the best fanin
    CostBest = 99;
    LeafBest = -1;
    Counter = -1;
//printf( "Evaluating fanins of the cut:\n" );
    Vec_IntForEachEntry( vFront, Leaf, i )
    {
        CostCur = Ivy_NodeGetLeafCostOne( p, Leaf, vInside );
//printf( "    Fanin %s has cost %d.\n", Ivy_ObjName(pNode), CostCur );
        if ( CostBest > CostCur )
        {
            CostBest = CostCur;
            LeafBest = Leaf;
            LeavesBest[0] = Leaf;
            Counter = 1;
        }
        else if ( CostBest == CostCur )
            LeavesBest[Counter++] = Leaf;

        if ( CostBest <= 1 ) // can be if ( CostBest <= 1 )
            break;
    }
    if ( CostBest == 99 )
        return 0;
//        return Ivy_NodeBuildCutLevelTwo_int( vInside, vFront, nFaninLimit );

    assert( CostBest < 3 );
    if ( Vec_IntSize(vFront) - 1 + CostBest > nSizeLimit )
        return 0;
//        return Ivy_NodeBuildCutLevelTwo_int( vInside, vFront, nFaninLimit );

    assert( Counter > 0 );
printf( "%d", Counter );

    LeafBest = LeavesBest[rand() % Counter];

    // remove the node from the array
    assert( LeafBest >= 0 );
    Vec_IntRemove( vFront, LeafBest );
//printf( "Removing fanin %s.\n", Ivy_ObjName(pNode) );

    // get the node and its latches
    pNode = Ivy_ManObj( p, Ivy_LeafId(LeafBest) );
    nLatches = Ivy_LeafLat(LeafBest) + Ivy_ObjIsLatch(pNode);
    assert( Ivy_ObjIsNode(pNode) || Ivy_ObjIsLatch(pNode) || Ivy_ObjIsBuf(pNode) );

    // add the left child to the fanins
    Next = Ivy_LeafCreate( Ivy_ObjFaninId0(pNode), nLatches );
    if ( Next && Vec_IntFind(vInside, Next) == -1 )
    {
//printf( "Adding fanin %s.\n", Ivy_ObjName(pNext) );
        Vec_IntPush( vFront, Next );
        Vec_IntPush( vInside, Next );
    }

    // quit if this is the one fanin node
    if ( Ivy_ObjIsLatch(pNode) || Ivy_ObjIsBuf(pNode) )
        return 1;
    assert( Ivy_ObjIsNode(pNode) );

    // add the right child to the fanins
    Next = Ivy_LeafCreate( Ivy_ObjFaninId1(pNode), nLatches );
    if ( Next && Vec_IntFind(vInside, Next) == -1 )
    {
//printf( "Adding fanin %s.\n", Ivy_ObjName(pNext) );
        Vec_IntPush( vFront, Next );
        Vec_IntPush( vInside, Next );
    }
    assert( Vec_IntSize(vFront) <= nSizeLimit );
    // keep doing this
    return 1;
}

/**Function*************************************************************

  Synopsis    [Computes one sequential cut of the given size.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_ManSeqFindCut( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Vec_Int_t * vFront, Vec_Int_t * vInside, int nSize )
{
    assert( !Ivy_IsComplement(pRoot) );
    assert( Ivy_ObjIsNode(pRoot) );
    assert( Ivy_ObjFaninId0(pRoot) );
    assert( Ivy_ObjFaninId1(pRoot) );

    // start the cut 
    Vec_IntClear( vFront );
    Vec_IntPush( vFront, Ivy_LeafCreate(Ivy_ObjFaninId0(pRoot), 0) );
    Vec_IntPush( vFront, Ivy_LeafCreate(Ivy_ObjFaninId1(pRoot), 0) );

    // start the visited nodes
    Vec_IntClear( vInside );
    Vec_IntPush( vInside, Ivy_LeafCreate(pRoot->Id, 0) );
    Vec_IntPush( vInside, Ivy_LeafCreate(Ivy_ObjFaninId0(pRoot), 0) );
    Vec_IntPush( vInside, Ivy_LeafCreate(Ivy_ObjFaninId1(pRoot), 0) );

    // compute the cut
    while ( Ivy_ManSeqFindCut_int( p, vFront, vInside, nSize ) );
    assert( Vec_IntSize(vFront) <= nSize );
}





/**Function*************************************************************

  Synopsis    [Computing Boolean cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_ManFindBoolCut_rec( Ivy_Man_t * p, Ivy_Obj_t * pObj, Vec_Ptr_t * vLeaves, Vec_Ptr_t * vVolume, Ivy_Obj_t * pPivot )
{
    int RetValue0, RetValue1;
    if ( pObj == pPivot )
    {
        Vec_PtrPushUnique( vLeaves, pObj );
        Vec_PtrPushUnique( vVolume, pObj );
        return 1;        
    }
    if ( pObj->fMarkA )
        return 0;

//    assert( !Ivy_ObjIsCi(pObj) );
    if ( Ivy_ObjIsCi(pObj) )
        return 0;

    if ( Ivy_ObjIsBuf(pObj) )
    {
        RetValue0 = Ivy_ManFindBoolCut_rec( p, Ivy_ObjFanin0(pObj), vLeaves, vVolume, pPivot );
        if ( !RetValue0 )
            return 0;
        Vec_PtrPushUnique( vVolume, pObj );
        return 1;
    }
    assert( Ivy_ObjIsNode(pObj) );
    RetValue0 = Ivy_ManFindBoolCut_rec( p, Ivy_ObjFanin0(pObj), vLeaves, vVolume, pPivot );
    RetValue1 = Ivy_ManFindBoolCut_rec( p, Ivy_ObjFanin1(pObj), vLeaves, vVolume, pPivot );
    if ( !RetValue0 && !RetValue1 )
        return 0;
    // add new leaves
    if ( !RetValue0 )
    {
        Vec_PtrPushUnique( vLeaves, Ivy_ObjFanin0(pObj) );
        Vec_PtrPushUnique( vVolume, Ivy_ObjFanin0(pObj) );
    }
    if ( !RetValue1 )
    {
        Vec_PtrPushUnique( vLeaves, Ivy_ObjFanin1(pObj) );
        Vec_PtrPushUnique( vVolume, Ivy_ObjFanin1(pObj) );
    }
    Vec_PtrPushUnique( vVolume, pObj );
    return 1;
}

/**Function*************************************************************

  Synopsis    [Returns the cost of one node (how many new nodes are added.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_ManFindBoolCutCost( Ivy_Obj_t * pObj )
{
    int Cost;
    // make sure the node is in the construction zone
    assert( pObj->fMarkA == 1 );  
    // cannot expand over the PI node
    if ( Ivy_ObjIsCi(pObj) )
        return 999;
    // always expand over the buffer
    if ( Ivy_ObjIsBuf(pObj) )
        return !Ivy_ObjFanin0(pObj)->fMarkA;
    // get the cost of the cone
    Cost = (!Ivy_ObjFanin0(pObj)->fMarkA) + (!Ivy_ObjFanin1(pObj)->fMarkA);
    // return the number of nodes to be added to the leaves if this node is removed
    return Cost;
}

/**Function*************************************************************

  Synopsis    [Computing Boolean cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_ManFindBoolCut( Ivy_Man_t * p, Ivy_Obj_t * pRoot, Vec_Ptr_t * vFront, Vec_Ptr_t * vVolume, Vec_Ptr_t * vLeaves )
{
    Ivy_Obj_t * pObj, * pFaninC, * pFanin0, * pFanin1, * pPivot;
    int RetValue, LevelLimit, Lev, k;
    assert( !Ivy_IsComplement(pRoot) );
    // clear the frontier and collect the nodes
    Vec_PtrClear( vFront );
    Vec_PtrClear( vVolume );
    if ( Ivy_ObjIsMuxType(pRoot) )
        pFaninC = Ivy_ObjRecognizeMux( pRoot, &pFanin0, &pFanin1 );
    else
    {
        pFaninC = NULL;
        pFanin0 = Ivy_ObjFanin0(pRoot);
        pFanin1 = Ivy_ObjFanin1(pRoot); 
    }
    // start cone A
    pFanin0->fMarkA = 1;
    Vec_PtrPush( vFront, pFanin0 );
    Vec_PtrPush( vVolume, pFanin0 );
    // start cone B
    pFanin1->fMarkB = 1;
    Vec_PtrPush( vFront, pFanin1 );
    Vec_PtrPush( vVolume, pFanin1 );
    // iteratively expand until the common node (pPivot) is found or limit is reached
    assert( Ivy_ObjLevel(pRoot) == Ivy_ObjLevelNew(pRoot) );
    pPivot = NULL;
    LevelLimit = IVY_MAX( Ivy_ObjLevel(pRoot) - 10, 1 );
    for ( Lev = Ivy_ObjLevel(pRoot) - 1; Lev >= LevelLimit; Lev-- )
    {
        while ( 1 )
        {
            // find the next node to expand on this level
            Vec_PtrForEachEntry( vFront, pObj, k )
                if ( (int)pObj->Level == Lev )
                    break;
            if ( k == Vec_PtrSize(vFront) )
                break;
            assert( (int)pObj->Level <= Lev );
            assert( pObj->fMarkA ^ pObj->fMarkB );
            // remove the old node
            Vec_PtrRemove( vFront, pObj );

            // expand this node
            pFanin0 = Ivy_ObjFanin0(pObj);
            if ( !pFanin0->fMarkA && !pFanin0->fMarkB )
            {
                Vec_PtrPush( vFront, pFanin0 );
                Vec_PtrPush( vVolume, pFanin0 );
            }
            // mark the new nodes
            if ( pObj->fMarkA )
                pFanin0->fMarkA = 1; 
            if ( pObj->fMarkB )
                pFanin0->fMarkB = 1; 

            if ( Ivy_ObjIsBuf(pObj) )
            {
                if ( pFanin0->fMarkA && pFanin0->fMarkB )
                {
                    pPivot = pFanin0;
                    break;
                }
                continue;
            }

            // expand this node
            pFanin1 = Ivy_ObjFanin1(pObj); 
            if ( !pFanin1->fMarkA && !pFanin1->fMarkB )
            {
                Vec_PtrPush( vFront, pFanin1 );
                Vec_PtrPush( vVolume, pFanin1 );
            }
            // mark the new nodes
            if ( pObj->fMarkA )
                pFanin1->fMarkA = 1; 
            if ( pObj->fMarkB )
                pFanin1->fMarkB = 1; 

            // consider if it is time to quit
            if ( pFanin0->fMarkA && pFanin0->fMarkB )
            {
                pPivot = pFanin0;
                break;
            }
            if ( pFanin1->fMarkA && pFanin1->fMarkB )
            {
                pPivot = pFanin1;
                break;
            }
        }
        if ( pPivot != NULL )
            break;
    }
    if ( pPivot == NULL )
        return 0;
    // if the MUX control is defined, it should not be
    if ( pFaninC && !pFaninC->fMarkA && !pFaninC->fMarkB )
        Vec_PtrPush( vFront, pFaninC );
    // clean the markings
    Vec_PtrForEachEntry( vVolume, pObj, k )
        pObj->fMarkA = pObj->fMarkB = 0;

    // mark the nodes on the frontier (including the pivot)
    Vec_PtrForEachEntry( vFront, pObj, k )
        pObj->fMarkA = 1;
    // cut exists, collect all the nodes on the shortest path to the pivot
    Vec_PtrClear( vLeaves );
    Vec_PtrClear( vVolume );
    RetValue = Ivy_ManFindBoolCut_rec( p, pRoot, vLeaves, vVolume, pPivot );
    assert( RetValue == 1 );
    // unmark the nodes on the frontier (including the pivot)
    Vec_PtrForEachEntry( vFront, pObj, k )
        pObj->fMarkA = 0;

    // mark the nodes in the volume
    Vec_PtrForEachEntry( vVolume, pObj, k )
        pObj->fMarkA = 1;
    // expand the cut without increasing its size
    while ( 1 )
    {
        Vec_PtrForEachEntry( vLeaves, pObj, k )
            if ( Ivy_ManFindBoolCutCost(pObj) < 2 )
                break;
        if ( k == Vec_PtrSize(vLeaves) )
            break;
        // the node can be expanded
        // remove the old node
        Vec_PtrRemove( vLeaves, pObj );
        // expand this node
        pFanin0 = Ivy_ObjFanin0(pObj);
        if ( !pFanin0->fMarkA )
        {
            pFanin0->fMarkA = 1;
            Vec_PtrPush( vVolume, pFanin0 );
            Vec_PtrPush( vLeaves, pFanin0 );
        }
        if ( Ivy_ObjIsBuf(pObj) )
            continue;
        // expand this node
        pFanin1 = Ivy_ObjFanin1(pObj);
        if ( !pFanin1->fMarkA )
        {
            pFanin1->fMarkA = 1;
            Vec_PtrPush( vVolume, pFanin1 );
            Vec_PtrPush( vLeaves, pFanin1 );
        }        
    }
    // unmark the nodes in the volume
    Vec_PtrForEachEntry( vVolume, pObj, k )
        pObj->fMarkA = 0;
    return 1;
}


/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_ManTestCutsBool( Ivy_Man_t * p )
{
    Vec_Ptr_t * vFront, * vVolume, * vLeaves;
    Ivy_Obj_t * pObj;//, * pTemp;
    int i, RetValue;//, k;
    vFront = Vec_PtrAlloc( 100 );
    vVolume = Vec_PtrAlloc( 100 );
    vLeaves = Vec_PtrAlloc( 100 );
    Ivy_ManForEachObj( p, pObj, i )
    {
        if ( !Ivy_ObjIsNode(pObj) )
            continue;
        if ( Ivy_ObjIsMuxType(pObj) )
        {
            printf( "m" );
            continue;
        }
        if ( Ivy_ObjIsExor(pObj) )
            printf( "x" );
        RetValue = Ivy_ManFindBoolCut( p, pObj, vFront, vVolume, vLeaves );
        if ( RetValue == 0 )
            printf( "- " );
        else
            printf( "%d ", Vec_PtrSize(vLeaves) );
/*        
        printf( "( " );
        Vec_PtrForEachEntry( vFront, pTemp, k )
            printf( "%d ", Ivy_ObjRefs(Ivy_Regular(pTemp)) );
        printf( ")\n" );
*/
    }
    printf( "\n" );
    Vec_PtrFree( vFront );
    Vec_PtrFree( vVolume );
    Vec_PtrFree( vLeaves );
}



/**Function*************************************************************

  Synopsis    [Find the hash value of the cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline unsigned Ivy_NodeCutHash( Ivy_Cut_t * pCut )
{
    int i;
//    for ( i = 1; i < pCut->nSize; i++ )
//        assert( pCut->pArray[i-1] < pCut->pArray[i] );
    pCut->uHash = 0;
    for ( i = 0; i < pCut->nSize; i++ )
        pCut->uHash |= (1 << (pCut->pArray[i] % 31));
    return pCut->uHash;
}

/**Function*************************************************************

  Synopsis    [Removes one node to the cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline void Ivy_NodeCutShrink( Ivy_Cut_t * pCut, int iOld )
{
    int i, k;
    for ( i = k = 0; i < pCut->nSize; i++ )
        if ( pCut->pArray[i] != iOld )
            pCut->pArray[k++] = pCut->pArray[i];
    assert( k == pCut->nSize - 1 );
    pCut->nSize--;
}

/**Function*************************************************************

  Synopsis    [Adds one node to the cut.]

  Description [Returns 1 if the cuts is still okay.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Ivy_NodeCutExtend( Ivy_Cut_t * pCut, int iNew )
{
    int i;
    for ( i = 0; i < pCut->nSize; i++ )
        if ( pCut->pArray[i] == iNew )
            return 1;
    // check if there is room
    if ( pCut->nSize == pCut->nSizeMax )
        return 0;
    // add the new one
    for ( i = pCut->nSize - 1; i >= 0; i-- )
        if ( pCut->pArray[i] > iNew )
            pCut->pArray[i+1] = pCut->pArray[i];
        else
        {
            assert( pCut->pArray[i] < iNew );
            break;
        }
    pCut->pArray[i+1] = iNew;
    pCut->nSize++;
    return 1;
}

/**Function*************************************************************

  Synopsis    [Returns 1 if the cut can be constructed; 0 otherwise.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Ivy_NodeCutPrescreen( Ivy_Cut_t * pCut, int Id0, int Id1 )
{
    int i;
    if ( pCut->nSize < pCut->nSizeMax )
        return 1;
    for ( i = 0; i < pCut->nSize; i++ )
        if ( pCut->pArray[i] == Id0 || pCut->pArray[i] == Id1 )
            return 1;
    return 0;
}

/**Function*************************************************************

  Synopsis    [Derives new cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Ivy_NodeCutDeriveNew( Ivy_Cut_t * pCut, Ivy_Cut_t * pCutNew, int IdOld, int IdNew0, int IdNew1 )
{
    unsigned uHash = 0;
    int i, k; 
    assert( pCut->nSize > 0 );
    assert( IdNew0 < IdNew1 );
    for ( i = k = 0; i < pCut->nSize; i++ )
    {
        if ( pCut->pArray[i] == IdOld )
            continue;
        if ( IdNew0 <= pCut->pArray[i] )
        {
            if ( IdNew0 < pCut->pArray[i] )
            {
                pCutNew->pArray[ k++ ] = IdNew0;
                uHash |= Ivy_NodeCutHashValue( IdNew0 );
            }
            IdNew0 = 0x7FFFFFFF;
        }
        if ( IdNew1 <= pCut->pArray[i] )
        {
            if ( IdNew1 < pCut->pArray[i] )
            {
                pCutNew->pArray[ k++ ] = IdNew1;
                uHash |= Ivy_NodeCutHashValue( IdNew1 );
            }
            IdNew1 = 0x7FFFFFFF;
        }
        pCutNew->pArray[ k++ ] = pCut->pArray[i];
        uHash |= Ivy_NodeCutHashValue( pCut->pArray[i] );
    }
    if ( IdNew0 < 0x7FFFFFFF )
    {
        pCutNew->pArray[ k++ ] = IdNew0;
        uHash |= Ivy_NodeCutHashValue( IdNew0 );
    }
    if ( IdNew1 < 0x7FFFFFFF )
    {
        pCutNew->pArray[ k++ ] = IdNew1;
        uHash |= Ivy_NodeCutHashValue( IdNew1 );
    }
    pCutNew->nSize = k;
    pCutNew->uHash = uHash;
    assert( pCutNew->nSize <= pCut->nSizeMax );
//    for ( i = 1; i < pCutNew->nSize; i++ )
//        assert( pCutNew->pArray[i-1] < pCutNew->pArray[i] );
    return 1;
}

/**Function*************************************************************

  Synopsis    [Check if the cut exists.]

  Description [Returns 1 if the cut exists.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_NodeCutFindOrAdd( Ivy_Store_t * pCutStore, Ivy_Cut_t * pCutNew )
{
    Ivy_Cut_t * pCut;
    int i, k;
    assert( pCutNew->uHash );
    // try to find the cut
    for ( i = 0; i < pCutStore->nCuts; i++ )
    {
        pCut = pCutStore->pCuts + i;
        if ( pCut->uHash == pCutNew->uHash && pCut->nSize == pCutNew->nSize )
        {
            for ( k = 0; k < pCutNew->nSize; k++ )
                if ( pCut->pArray[k] != pCutNew->pArray[k] )
                    break;
            if ( k == pCutNew->nSize )
                return 1;
        }
    }
    assert( pCutStore->nCuts < pCutStore->nCutsMax );
    // add the cut
    pCut = pCutStore->pCuts + pCutStore->nCuts++;
    *pCut = *pCutNew;
    return 0;
}

/**Function*************************************************************

  Synopsis    [Returns 1 if pDom is contained in pCut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline int Ivy_CutCheckDominance( Ivy_Cut_t * pDom, Ivy_Cut_t * pCut )
{
    int i, k;
    for ( i = 0; i < pDom->nSize; i++ )
    {
        for ( k = 0; k < pCut->nSize; k++ )
            if ( pDom->pArray[i] == pCut->pArray[k] )
                break;
        if ( k == pCut->nSize ) // node i in pDom is not contained in pCut
            return 0;
    }
    // every node in pDom is contained in pCut
    return 1;
}

/**Function*************************************************************

  Synopsis    [Check if the cut exists.]

  Description [Returns 1 if the cut exists.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Ivy_NodeCutFindOrAddFilter( Ivy_Store_t * pCutStore, Ivy_Cut_t * pCutNew )
{
    Ivy_Cut_t * pCut;
    int i, k;
    assert( pCutNew->uHash );
    // try to find the cut
    for ( i = 0; i < pCutStore->nCuts; i++ )
    {
        pCut = pCutStore->pCuts + i;
        if ( pCut->nSize == 0 )
            continue;
        if ( pCut->nSize == pCutNew->nSize )
        {
            if ( pCut->uHash == pCutNew->uHash )
            {
                for ( k = 0; k < pCutNew->nSize; k++ )
                    if ( pCut->pArray[k] != pCutNew->pArray[k] )
                        break;
                if ( k == pCutNew->nSize )
                    return 1;
            }
            continue;
        }
        if ( pCut->nSize < pCutNew->nSize )
        {
            // skip the non-contained cuts
            if ( (pCut->uHash & pCutNew->uHash) != pCut->uHash )
                continue;
            // check containment seriously
            if ( Ivy_CutCheckDominance( pCut, pCutNew ) )
                return 1;
            continue;
        }
        // check potential containment of other cut

        // skip the non-contained cuts
        if ( (pCut->uHash & pCutNew->uHash) != pCutNew->uHash )
            continue;
        // check containment seriously
        if ( Ivy_CutCheckDominance( pCutNew, pCut ) )
        {
            // remove the current cut
//            --pCutStore->nCuts;
//            for ( k = i; k < pCutStore->nCuts; k++ )
//                pCutStore->pCuts[k] = pCutStore->pCuts[k+1];
//            i--;
            pCut->nSize = 0;
        }
    }
    assert( pCutStore->nCuts < pCutStore->nCutsMax );
    // add the cut
    pCut = pCutStore->pCuts + pCutStore->nCuts++;
    *pCut = *pCutNew;
    return 0;
}

/**Function*************************************************************

  Synopsis    [Print the cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_NodeCompactCuts( Ivy_Store_t * pCutStore )
{
    Ivy_Cut_t * pCut;
    int i, k;
    for ( i = k = 0; i < pCutStore->nCuts; i++ )
    {
        pCut = pCutStore->pCuts + i;
        if ( pCut->nSize == 0 )
            continue;
        pCutStore->pCuts[k++] = *pCut;
    }
    pCutStore->nCuts = k;
}

/**Function*************************************************************

  Synopsis    [Print the cut.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_NodePrintCut( Ivy_Cut_t * pCut )
{
    int i;
    assert( pCut->nSize > 0 );
    printf( "%d : {", pCut->nSize );
    for ( i = 0; i < pCut->nSize; i++ )
        printf( " %d", pCut->pArray[i] );
    printf( " }\n" );
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_NodePrintCuts( Ivy_Store_t * pCutStore )
{
    int i;
    printf( "Node %d\n", pCutStore->pCuts[0].pArray[0] );
    for ( i = 0; i < pCutStore->nCuts; i++ )
        Ivy_NodePrintCut( pCutStore->pCuts + i );
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static inline Ivy_Obj_t * Ivy_ObjRealFanin( Ivy_Obj_t * pObj )
{
    if ( !Ivy_ObjIsBuf(pObj) )
        return pObj;
    return Ivy_ObjRealFanin( Ivy_ObjFanin0(pObj) );
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Store_t * Ivy_NodeFindCutsAll( Ivy_Man_t * p, Ivy_Obj_t * pObj, int nLeaves )
{
    static Ivy_Store_t CutStore, * pCutStore = &CutStore;
    Ivy_Cut_t CutNew, * pCutNew = &CutNew, * pCut;
    Ivy_Obj_t * pLeaf;
    int i, k, iLeaf0, iLeaf1;

    assert( nLeaves <= IVY_CUT_INPUT );

    // start the structure
    pCutStore->nCuts = 0;
    pCutStore->nCutsMax = IVY_CUT_LIMIT;
    // start the trivial cut
    pCutNew->uHash = 0;
    pCutNew->nSize = 1;
    pCutNew->nSizeMax = nLeaves;
    pCutNew->pArray[0] = pObj->Id;
    Ivy_NodeCutHash( pCutNew );
    // add the trivial cut
    Ivy_NodeCutFindOrAdd( pCutStore, pCutNew );
    assert( pCutStore->nCuts == 1 );

    // explore the cuts
    for ( i = 0; i < pCutStore->nCuts; i++ )
    {
        // expand this cut
        pCut = pCutStore->pCuts + i;
        if ( pCut->nSize == 0 )
            continue;
        for ( k = 0; k < pCut->nSize; k++ )
        {
            pLeaf = Ivy_ManObj( p, pCut->pArray[k] );
            if ( Ivy_ObjIsCi(pLeaf) )
                continue;
/*
            *pCutNew = *pCut;
            Ivy_NodeCutShrink( pCutNew, pLeaf->Id );
            if ( !Ivy_NodeCutExtend( pCutNew, Ivy_ObjFaninId0(pLeaf) ) )
                continue;
            if ( Ivy_ObjIsNode(pLeaf) && !Ivy_NodeCutExtend( pCutNew, Ivy_ObjFaninId1(pLeaf) ) )
                continue;
            Ivy_NodeCutHash( pCutNew );
*/
            iLeaf0 = Ivy_ObjId( Ivy_ObjRealFanin(Ivy_ObjFanin0(pLeaf)) );
            iLeaf1 = Ivy_ObjId( Ivy_ObjRealFanin(Ivy_ObjFanin1(pLeaf)) );
//            if ( iLeaf0 == iLeaf1 ) // strange situation observed on Jan 18, 2007
//                continue;
            if ( !Ivy_NodeCutPrescreen( pCut, iLeaf0, iLeaf1 ) )
                continue;
            if ( iLeaf0 > iLeaf1 )
                Ivy_NodeCutDeriveNew( pCut, pCutNew, pCut->pArray[k], iLeaf1, iLeaf0 );
            else
                Ivy_NodeCutDeriveNew( pCut, pCutNew, pCut->pArray[k], iLeaf0, iLeaf1 );
            Ivy_NodeCutFindOrAddFilter( pCutStore, pCutNew );
            if ( pCutStore->nCuts == IVY_CUT_LIMIT )
                break;
        }
        if ( pCutStore->nCuts == IVY_CUT_LIMIT )
            break;
    }
    Ivy_NodeCompactCuts( pCutStore );
//    Ivy_NodePrintCuts( pCutStore );
    return pCutStore;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
void Ivy_ManTestCutsAll( Ivy_Man_t * p )
{
    Ivy_Obj_t * pObj;
    int i, nCutsCut, nCutsTotal, nNodeTotal, nNodeOver;
    int clk = clock();
    nNodeTotal = nNodeOver = 0;
    nCutsTotal = -Ivy_ManNodeNum(p);
    Ivy_ManForEachObj( p, pObj, i )
    {
        if ( !Ivy_ObjIsNode(pObj) )
            continue;
        nCutsCut    = Ivy_NodeFindCutsAll( p, pObj, 5 )->nCuts;
        nCutsTotal += nCutsCut;
        nNodeOver  += (nCutsCut == IVY_CUT_LIMIT);
        nNodeTotal++;
    }
    printf( "Total cuts = %6d. Trivial = %6d.   Nodes = %6d. Satur = %6d.  ", 
        nCutsTotal, Ivy_ManPiNum(p) + Ivy_ManNodeNum(p), nNodeTotal, nNodeOver );
    PRT( "Time", clock() - clk );
}

////////////////////////////////////////////////////////////////////////
///                       END OF FILE                                ///
////////////////////////////////////////////////////////////////////////