src/aig/ivy/ivyDsd.c

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#include "ivy.h"


// decomposition types
typedef enum { 
    IVY_DEC_PI,             // 0: var
    IVY_DEC_CONST1,         // 1: CONST1
    IVY_DEC_BUF,            // 2: BUF
    IVY_DEC_AND,            // 3: AND
    IVY_DEC_EXOR,           // 4: EXOR
    IVY_DEC_MUX,            // 5: MUX
    IVY_DEC_MAJ,            // 6: MAJ
    IVY_DEC_PRIME           // 7: undecomposable
} Ivy_DecType_t;

typedef struct Ivy_Dec_t_ Ivy_Dec_t;
struct Ivy_Dec_t_
{
    unsigned  Type   : 4;   // the node type (PI, CONST1, AND, EXOR, MUX, PRIME)
    unsigned  fCompl : 1;   // shows if node is complemented (root node only)
    unsigned  nFans  : 3;   // the number of fanins
    unsigned  Fan0   : 4;   // fanin 0
    unsigned  Fan1   : 4;   // fanin 1 
    unsigned  Fan2   : 4;   // fanin 2
    unsigned  Fan3   : 4;   // fanin 3 
    unsigned  Fan4   : 4;   // fanin 4 
    unsigned  Fan5   : 4;   // fanin 5
};

static inline int        Ivy_DecToInt( Ivy_Dec_t Node )     { return *((int *)&Node);       }
static inline Ivy_Dec_t  Ivy_IntToDec( int Node )           { return *((Ivy_Dec_t *)&Node); }
static inline void       Ivy_DecClear( Ivy_Dec_t * pNode )  { *((int *)pNode) = 0;          }


static unsigned s_Masks[6][2] = {
    { 0x55555555, 0xAAAAAAAA },
    { 0x33333333, 0xCCCCCCCC },
    { 0x0F0F0F0F, 0xF0F0F0F0 },
    { 0x00FF00FF, 0xFF00FF00 },
    { 0x0000FFFF, 0xFFFF0000 },
    { 0x00000000, 0xFFFFFFFF }
};

static inline int        Ivy_TruthWordCountOnes( unsigned uWord )
{
    uWord = (uWord & 0x55555555) + ((uWord>>1) & 0x55555555);
    uWord = (uWord & 0x33333333) + ((uWord>>2) & 0x33333333);
    uWord = (uWord & 0x0F0F0F0F) + ((uWord>>4) & 0x0F0F0F0F);
    uWord = (uWord & 0x00FF00FF) + ((uWord>>8) & 0x00FF00FF);
    return  (uWord & 0x0000FFFF) + (uWord>>16);
}

static inline int        Ivy_TruthCofactorIsConst( unsigned uTruth, int Var, int Cof, int Const )
{
    if ( Const == 0 )
        return (uTruth & s_Masks[Var][Cof]) == 0;
    else
        return (uTruth & s_Masks[Var][Cof]) == s_Masks[Var][Cof];
}

static inline int        Ivy_TruthCofactorIsOne( unsigned uTruth, int Var )
{
    return (uTruth & s_Masks[Var][0]) == 0;
}

static inline unsigned   Ivy_TruthCofactor( unsigned uTruth, int Var )
{
    unsigned uCofactor = uTruth & s_Masks[Var >> 1][(Var & 1) == 0];
    int Shift = (1 << (Var >> 1));
    if ( Var & 1 )
        return uCofactor | (uCofactor << Shift);
    return uCofactor | (uCofactor >> Shift);
}

static inline unsigned   Ivy_TruthCofactor2( unsigned uTruth, int Var0, int Var1 )
{
    return Ivy_TruthCofactor( Ivy_TruthCofactor(uTruth, Var0), Var1 );
}

// returns 1 if the truth table depends on this var (var is regular interger var)
static inline int        Ivy_TruthDepends( unsigned uTruth, int Var )
{
    return Ivy_TruthCofactor(uTruth, Var << 1) != Ivy_TruthCofactor(uTruth, (Var << 1) | 1);
}

static inline void       Ivy_DecSetVar( Ivy_Dec_t * pNode, int iNum, unsigned Var )
{
    assert( iNum >= 0 && iNum <= 5 );
    switch( iNum )
    {
        case 0: pNode->Fan0 = Var; break;
        case 1: pNode->Fan1 = Var; break;
        case 2: pNode->Fan2 = Var; break;
        case 3: pNode->Fan3 = Var; break;
        case 4: pNode->Fan4 = Var; break;
        case 5: pNode->Fan5 = Var; break;
    }
}

static inline unsigned   Ivy_DecGetVar( Ivy_Dec_t * pNode, int iNum )
{
    assert( iNum >= 0 && iNum <= 5 );
    switch( iNum )
    {
        case 0: return pNode->Fan0;
        case 1: return pNode->Fan1;
        case 2: return pNode->Fan2;
        case 3: return pNode->Fan3;
        case 4: return pNode->Fan4;
        case 5: return pNode->Fan5;
    }
    return ~0;
}

static int   Ivy_TruthDecompose_rec( unsigned uTruth, Vec_Int_t * vTree );
static int   Ivy_TruthRecognizeMuxMaj( unsigned uTruth, int * pSupp, int nSupp, Vec_Int_t * vTree );

//int nTruthDsd;


int Ivy_TruthDsd( unsigned uTruth, Vec_Int_t * vTree )
{
    Ivy_Dec_t Node;
    int i, RetValue;
    // set the PI variables
    Vec_IntClear( vTree );
    for ( i = 0; i < 5; i++ )
        Vec_IntPush( vTree, 0 );
    // check if it is a constant
    if ( uTruth == 0 || ~uTruth == 0 )
    {
        Ivy_DecClear( &Node );
        Node.Type = IVY_DEC_CONST1;
        Node.fCompl = (uTruth == 0);
        Vec_IntPush( vTree, Ivy_DecToInt(Node) );
        return 1;
    }
    // perform the decomposition
    RetValue = Ivy_TruthDecompose_rec( uTruth, vTree );
    if ( RetValue == -1 )
        return 0;
    // get the topmost node
    if ( (RetValue >> 1) < 5 )
    { // add buffer
        Ivy_DecClear( &Node );
        Node.Type = IVY_DEC_BUF;
        Node.fCompl = (RetValue & 1);
        Node.Fan0 = ((RetValue >> 1) << 1);
        Vec_IntPush( vTree, Ivy_DecToInt(Node) );
    }
    else if ( RetValue & 1 )
    { // check if the topmost node has to be complemented
        Node = Ivy_IntToDec( Vec_IntPop(vTree) );
        assert( Node.fCompl == 0 );
        Node.fCompl = (RetValue & 1);
        Vec_IntPush( vTree, Ivy_DecToInt(Node) );
    }
    if ( uTruth != Ivy_TruthDsdCompute(vTree) )
        printf( "Verification failed.\n" );
    return 1;
}

int Ivy_TruthDecompose_rec( unsigned uTruth, Vec_Int_t * vTree )
{
    Ivy_Dec_t Node;
    int Supp[5], Vars0[5], Vars1[5], Vars2[5], * pVars;
    int nSupp, Count0, Count1, Count2, nVars, RetValue, fCompl, i;
    unsigned uTruthCof, uCof0, uCof1;

    // get constant confactors
    Count0 = Count1 = Count2 = nSupp = 0;
    for ( i = 0; i < 5; i++ )
    {
        if ( Ivy_TruthCofactorIsConst(uTruth, i, 0, 0) )
            Vars0[Count0++] = (i << 1) | 0;
        else if ( Ivy_TruthCofactorIsConst(uTruth, i, 1, 0) )
            Vars0[Count0++] = (i << 1) | 1;
        else if ( Ivy_TruthCofactorIsConst(uTruth, i, 0, 1) )
            Vars1[Count1++] = (i << 1) | 0;
        else if ( Ivy_TruthCofactorIsConst(uTruth, i, 1, 1) )
            Vars1[Count1++] = (i << 1) | 1;
        else
        {
            uCof0 = Ivy_TruthCofactor( uTruth, (i << 1) | 1 );
            uCof1 = Ivy_TruthCofactor( uTruth, (i << 1) | 0 );
            if ( uCof0 == ~uCof1 )
                Vars2[Count2++] = (i << 1) | 0;
            else if ( uCof0 != uCof1 )
                Supp[nSupp++] = i;
        }
    }
    assert( Count0 == 0 || Count1 == 0 );
    assert( Count0 == 0 || Count2 == 0 );
    assert( Count1 == 0 || Count2 == 0 );

    // consider the case of a single variable
    if ( Count0 == 1 && nSupp == 0 )
        return Vars0[0];

    // consider more complex decompositions
    if ( Count0 == 0 && Count1 == 0 && Count2 == 0 )
        return Ivy_TruthRecognizeMuxMaj( uTruth, Supp, nSupp, vTree );

    // extract the nodes
    Ivy_DecClear( &Node );
    if ( Count0 > 0 )
        nVars = Count0, pVars = Vars0, Node.Type = IVY_DEC_AND,  fCompl = 0;
    else if ( Count1 > 0 )
        nVars = Count1, pVars = Vars1, Node.Type = IVY_DEC_AND,  fCompl = 1, uTruth = ~uTruth;
    else if ( Count2 > 0 )
        nVars = Count2, pVars = Vars2, Node.Type = IVY_DEC_EXOR, fCompl = 0;
    else 
        assert( 0 );
    Node.nFans = nVars+(nSupp>0);

    // compute cofactor
    uTruthCof = uTruth;
    for ( i = 0; i < nVars; i++ )
    {
        uTruthCof = Ivy_TruthCofactor( uTruthCof, pVars[i] );
        Ivy_DecSetVar( &Node, i, pVars[i] );
    }

    if ( Node.Type == IVY_DEC_EXOR )
        fCompl ^= ((Node.nFans & 1) == 0);

    if ( nSupp > 0 )
    {
        assert( uTruthCof != 0 && ~uTruthCof != 0 );
        // call recursively
        RetValue = Ivy_TruthDecompose_rec( uTruthCof, vTree );
        // quit if non-decomposable
        if ( RetValue == -1 )
            return -1;
        // remove the complement from the child if the node is EXOR
        if ( Node.Type == IVY_DEC_EXOR && (RetValue & 1) )
        {
            fCompl ^= 1;
            RetValue ^= 1;
        }
        // set the new decomposition
        Ivy_DecSetVar( &Node, nVars, RetValue );
    }
    else if ( Node.Type == IVY_DEC_EXOR )
        fCompl ^= (uTruthCof == 0);

    Vec_IntPush( vTree, Ivy_DecToInt(Node) );
    return ((Vec_IntSize(vTree)-1) << 1) | fCompl;
}

int Ivy_TruthRecognizeMuxMaj( unsigned uTruth, int * pSupp, int nSupp, Vec_Int_t * vTree )
{
    Ivy_Dec_t Node;
    int i, k, RetValue0, RetValue1;
    unsigned uCof0, uCof1, Num;
    char Count[3];
    assert( nSupp >= 3 );
    // start the node
    Ivy_DecClear( &Node );
    Node.Type = IVY_DEC_MUX;
    Node.nFans = 3;
    // try each of the variables
    for ( i = 0; i < nSupp; i++ )
    {
        // get the cofactors with respect to these variables
        uCof0 = Ivy_TruthCofactor( uTruth, (pSupp[i] << 1) | 1 );
        uCof1 = Ivy_TruthCofactor( uTruth,  pSupp[i] << 1 );
        // go through all other variables and make sure 
        // each of them belongs to the support of one cofactor
        for ( k = 0; k < nSupp; k++ )
        {
            if ( k == i )
                continue;
            if ( Ivy_TruthDepends(uCof0, pSupp[k]) && Ivy_TruthDepends(uCof1, pSupp[k]) )
                break;
        }
        if ( k < nSupp )
            continue;
        // MUX decomposition exists
        RetValue0 = Ivy_TruthDecompose_rec( uCof0, vTree );
        if ( RetValue0 == -1 )
            break;
        RetValue1 = Ivy_TruthDecompose_rec( uCof1, vTree );
        if ( RetValue1 == -1 )
            break;
        // both of them exist; create the node
        Ivy_DecSetVar( &Node, 0, pSupp[i] << 1 );
        Ivy_DecSetVar( &Node, 1, RetValue1 );
        Ivy_DecSetVar( &Node, 2, RetValue0 );
        Vec_IntPush( vTree, Ivy_DecToInt(Node) );
        return ((Vec_IntSize(vTree)-1) << 1) | 0;
    }
    // check majority gate
    if ( nSupp > 3 )
        return -1;
    if ( Ivy_TruthWordCountOnes(uTruth) != 16 )
        return -1;
    // this is a majority gate; determine polarity
    Node.Type = IVY_DEC_MAJ;
    Count[0] = Count[1] = Count[2] = 0;
    for ( i = 0; i < 8; i++ )
    {
        Num = 0;
        for ( k = 0; k < 3; k++ )
            if ( i & (1 << k) )
                Num |= (1 << pSupp[k]);
        assert( Num < 32 );
        if ( (uTruth & (1 << Num)) == 0 )
            continue;
        for ( k = 0; k < 3; k++ )
            if ( i & (1 << k) )
                Count[k]++;
    }
    assert( Count[0] == 1 || Count[0] == 3 );
    assert( Count[1] == 1 || Count[1] == 3 );
    assert( Count[2] == 1 || Count[2] == 3 );
    Ivy_DecSetVar( &Node, 0, (pSupp[0] << 1)|(Count[0] == 1) );
    Ivy_DecSetVar( &Node, 1, (pSupp[1] << 1)|(Count[1] == 1) );
    Ivy_DecSetVar( &Node, 2, (pSupp[2] << 1)|(Count[2] == 1) );
    Vec_IntPush( vTree, Ivy_DecToInt(Node) );
    return ((Vec_IntSize(vTree)-1) << 1) | 0;
}


unsigned Ivy_TruthDsdCompute_rec( int iNode, Vec_Int_t * vTree )
{
    unsigned uTruthChild, uTruthTotal;
    int Var, i;
    // get the node
    Ivy_Dec_t Node = Ivy_IntToDec( Vec_IntEntry(vTree, iNode) );
    // compute the node function
    if ( Node.Type == IVY_DEC_CONST1 )
        return s_Masks[5][ !Node.fCompl ];
    if ( Node.Type == IVY_DEC_PI )
        return s_Masks[iNode][ !Node.fCompl ];
    if ( Node.Type == IVY_DEC_BUF )
    {
        uTruthTotal = Ivy_TruthDsdCompute_rec( Node.Fan0 >> 1, vTree );
        return Node.fCompl? ~uTruthTotal : uTruthTotal;
    }
    if ( Node.Type == IVY_DEC_AND )
    {
        uTruthTotal = s_Masks[5][1];
        for ( i = 0; i < (int)Node.nFans; i++ )
        {
            Var = Ivy_DecGetVar( &Node, i );
            uTruthChild = Ivy_TruthDsdCompute_rec( Var >> 1, vTree );
            uTruthTotal = (Var & 1)? uTruthTotal & ~uTruthChild : uTruthTotal & uTruthChild;
        }
        return Node.fCompl? ~uTruthTotal : uTruthTotal;
    }
    if ( Node.Type == IVY_DEC_EXOR )
    {
        uTruthTotal = 0;
        for ( i = 0; i < (int)Node.nFans; i++ )
        {
            Var = Ivy_DecGetVar( &Node, i );
            uTruthTotal ^= Ivy_TruthDsdCompute_rec( Var >> 1, vTree );
            assert( (Var & 1) == 0 );
        }
        return Node.fCompl? ~uTruthTotal : uTruthTotal;
    }
    assert( Node.fCompl == 0 );
    if ( Node.Type == IVY_DEC_MUX || Node.Type == IVY_DEC_MAJ )
    {
        unsigned uTruthChildC, uTruthChild1, uTruthChild0;
        int VarC, Var1, Var0;
        VarC = Ivy_DecGetVar( &Node, 0 );
        Var1 = Ivy_DecGetVar( &Node, 1 );
        Var0 = Ivy_DecGetVar( &Node, 2 );
        uTruthChildC = Ivy_TruthDsdCompute_rec( VarC >> 1, vTree );
        uTruthChild1 = Ivy_TruthDsdCompute_rec( Var1 >> 1, vTree );
        uTruthChild0 = Ivy_TruthDsdCompute_rec( Var0 >> 1, vTree );
        assert( Node.Type == IVY_DEC_MAJ || (VarC & 1) == 0 );
        uTruthChildC = (VarC & 1)? ~uTruthChildC : uTruthChildC;
        uTruthChild1 = (Var1 & 1)? ~uTruthChild1 : uTruthChild1;
        uTruthChild0 = (Var0 & 1)? ~uTruthChild0 : uTruthChild0;
        if ( Node.Type == IVY_DEC_MUX )
            return (uTruthChildC & uTruthChild1) | (~uTruthChildC & uTruthChild0);
        else
            return (uTruthChildC & uTruthChild1) | (uTruthChildC & uTruthChild0) | (uTruthChild1 & uTruthChild0);
    }
    assert( 0 );
    return 0;
}


unsigned Ivy_TruthDsdCompute( Vec_Int_t * vTree )
{
    return Ivy_TruthDsdCompute_rec( Vec_IntSize(vTree)-1, vTree );
}

void Ivy_TruthDsdPrint_rec( FILE * pFile, int iNode, Vec_Int_t * vTree )
{
    int Var, i;
    // get the node
    Ivy_Dec_t Node = Ivy_IntToDec( Vec_IntEntry(vTree, iNode) );
    // compute the node function
    if ( Node.Type == IVY_DEC_CONST1 )
        fprintf( pFile, "Const1%s", (Node.fCompl? "\'" : "") );
    else if ( Node.Type == IVY_DEC_PI )
        fprintf( pFile, "%c%s", 'a' + iNode, (Node.fCompl? "\'" : "") );
    else if ( Node.Type == IVY_DEC_BUF )
    {
        Ivy_TruthDsdPrint_rec( pFile, Node.Fan0 >> 1, vTree );
        fprintf( pFile, "%s", (Node.fCompl? "\'" : "") );
    }
    else if ( Node.Type == IVY_DEC_AND )
    {
        fprintf( pFile, "AND(" );
        for ( i = 0; i < (int)Node.nFans; i++ )
        {
            Var = Ivy_DecGetVar( &Node, i );
            Ivy_TruthDsdPrint_rec( pFile, Var >> 1, vTree );
            fprintf( pFile, "%s", (Var & 1)? "\'" : "" );
            if ( i != (int)Node.nFans-1 )
                fprintf( pFile, "," );
        }
        fprintf( pFile, ")%s", (Node.fCompl? "\'" : "") );
    }
    else if ( Node.Type == IVY_DEC_EXOR )
    {
        fprintf( pFile, "EXOR(" );
        for ( i = 0; i < (int)Node.nFans; i++ )
        {
            Var = Ivy_DecGetVar( &Node, i );
            Ivy_TruthDsdPrint_rec( pFile, Var >> 1, vTree );
            if ( i != (int)Node.nFans-1 )
                fprintf( pFile, "," );
            assert( (Var & 1) == 0 );
        }
        fprintf( pFile, ")%s", (Node.fCompl? "\'" : "") );
    }
    else if ( Node.Type == IVY_DEC_MUX || Node.Type == IVY_DEC_MAJ )
    {
        int VarC, Var1, Var0;
        assert( Node.fCompl == 0 );
        VarC = Ivy_DecGetVar( &Node, 0 );
        Var1 = Ivy_DecGetVar( &Node, 1 );
        Var0 = Ivy_DecGetVar( &Node, 2 );
        fprintf( pFile, "%s", (Node.Type == IVY_DEC_MUX)? "MUX(" : "MAJ(" );
        Ivy_TruthDsdPrint_rec( pFile, VarC >> 1, vTree );
        fprintf( pFile, "%s", (VarC & 1)? "\'" : "" );
        fprintf( pFile, "," );
        Ivy_TruthDsdPrint_rec( pFile, Var1 >> 1, vTree );
        fprintf( pFile, "%s", (Var1 & 1)? "\'" : "" );
        fprintf( pFile, "," );
        Ivy_TruthDsdPrint_rec( pFile, Var0 >> 1, vTree );
        fprintf( pFile, "%s", (Var0 & 1)? "\'" : "" );
        fprintf( pFile, ")" );
    }
    else assert( 0 );
}


void Ivy_TruthDsdPrint( FILE * pFile, Vec_Int_t * vTree )
{
    fprintf( pFile, "F = " );
    Ivy_TruthDsdPrint_rec( pFile, Vec_IntSize(vTree)-1, vTree );
    fprintf( pFile, "\n" );
}

Ivy_Obj_t * Ivy_ManDsdConstruct_rec( Ivy_Man_t * p, Vec_Int_t * vFront, int iNode, Vec_Int_t * vTree )
{
    Ivy_Obj_t * pResult, * pChild, * pNodes[16];
    int Var, i;
    // get the node
    Ivy_Dec_t Node = Ivy_IntToDec( Vec_IntEntry(vTree, iNode) );
    // compute the node function
    if ( Node.Type == IVY_DEC_CONST1 )
        return Ivy_NotCond( Ivy_ManConst1(p), Node.fCompl );
    if ( Node.Type == IVY_DEC_PI )
    {
        pResult = Ivy_ManObj( p, Vec_IntEntry(vFront, iNode) );
        return Ivy_NotCond( pResult, Node.fCompl );
    }
    if ( Node.Type == IVY_DEC_BUF )
    {
        pResult = Ivy_ManDsdConstruct_rec( p, vFront, Node.Fan0 >> 1, vTree );
        return Ivy_NotCond( pResult, Node.fCompl );
    }
    if ( Node.Type == IVY_DEC_AND || Node.Type == IVY_DEC_EXOR )
    {
        for ( i = 0; i < (int)Node.nFans; i++ )
        {
            Var = Ivy_DecGetVar( &Node, i );
            assert( Node.Type == IVY_DEC_AND || (Var & 1) == 0 );
            pChild = Ivy_ManDsdConstruct_rec( p, vFront, Var >> 1, vTree );
            pChild = Ivy_NotCond( pChild, (Var & 1) );
            pNodes[i] = pChild;
        }

//        Ivy_MultiEval( pNodes, Node.nFans, Node.Type == IVY_DEC_AND ? IVY_AND : IVY_EXOR );

        pResult = Ivy_Multi( p, pNodes, Node.nFans, Node.Type == IVY_DEC_AND ? IVY_AND : IVY_EXOR );
        return Ivy_NotCond( pResult, Node.fCompl );
    }
    assert( Node.fCompl == 0 );
    if ( Node.Type == IVY_DEC_MUX || Node.Type == IVY_DEC_MAJ )
    {
        int VarC, Var1, Var0;
        VarC = Ivy_DecGetVar( &Node, 0 );
        Var1 = Ivy_DecGetVar( &Node, 1 );
        Var0 = Ivy_DecGetVar( &Node, 2 );
        pNodes[0] = Ivy_ManDsdConstruct_rec( p, vFront, VarC >> 1, vTree );
        pNodes[1] = Ivy_ManDsdConstruct_rec( p, vFront, Var1 >> 1, vTree );
        pNodes[2] = Ivy_ManDsdConstruct_rec( p, vFront, Var0 >> 1, vTree );
        assert( Node.Type == IVY_DEC_MAJ || (VarC & 1) == 0 );
        pNodes[0] = Ivy_NotCond( pNodes[0], (VarC & 1) );
        pNodes[1] = Ivy_NotCond( pNodes[1], (Var1 & 1) );
        pNodes[2] = Ivy_NotCond( pNodes[2], (Var0 & 1) );
        if ( Node.Type == IVY_DEC_MUX )
            return Ivy_Mux( p, pNodes[0], pNodes[1], pNodes[2] );
        else
            return Ivy_Maj( p, pNodes[0], pNodes[1], pNodes[2] );
    }
    assert( 0 );
    return 0;
}

Ivy_Obj_t * Ivy_ManDsdConstruct( Ivy_Man_t * p, Vec_Int_t * vFront, Vec_Int_t * vTree )
{
    int Entry, i;
    // implement latches on the frontier (TEMPORARY!!!)
    Vec_IntForEachEntry( vFront, Entry, i )
        Vec_IntWriteEntry( vFront, i, Ivy_LeafId(Entry) );
    // recursively construct the tree
    return Ivy_ManDsdConstruct_rec( p, vFront, Vec_IntSize(vTree)-1, vTree );
}



void Ivy_TruthDsdComputePrint( unsigned uTruth )
{
    static Vec_Int_t * vTree = NULL;
    if ( vTree == NULL )
        vTree = Vec_IntAlloc( 12 );
    if ( Ivy_TruthDsd( uTruth, vTree ) )
        Ivy_TruthDsdPrint( stdout, vTree );
    else
        printf( "Undecomposable\n" );
}

void Ivy_TruthTestOne( unsigned uTruth )
{
    static int Counter = 0;
    static Vec_Int_t * vTree = NULL;
    // decompose
    if ( vTree == NULL )
        vTree = Vec_IntAlloc( 12 );

    if ( !Ivy_TruthDsd( uTruth, vTree ) )
    {
//        printf( "Undecomposable\n" );
    }
    else
    {
//        nTruthDsd++;
        printf( "%5d : ", Counter++ );
        Extra_PrintBinary( stdout, &uTruth, 32 );
        printf( "  " );
        Ivy_TruthDsdPrint( stdout, vTree );
        if ( uTruth != Ivy_TruthDsdCompute(vTree) )
            printf( "Verification failed.\n" );
    }
//    Vec_IntFree( vTree );
}

void Ivy_TruthTest()
{
    FILE * pFile;
    char Buffer[100];
    unsigned uTruth;
    int i;

    pFile = fopen( "npn4.txt", "r" );
    for ( i = 0; i < 222; i++ )
//    pFile = fopen( "npn5.txt", "r" );
//    for ( i = 0; i < 616126; i++ )
    {
        fscanf( pFile, "%s", Buffer );
        Extra_ReadHexadecimal( &uTruth, Buffer+2, 4 );
//        Extra_ReadHexadecimal( &uTruth, Buffer+2, 5 );
        uTruth |= (uTruth << 16);
//        uTruth = ~uTruth;
        Ivy_TruthTestOne( uTruth );
    }
    fclose( pFile );
}

void Ivy_TruthTest3()
{
    FILE * pFile;
    char Buffer[100];
    unsigned uTruth;
    int i;

    pFile = fopen( "npn3.txt", "r" );
    for ( i = 0; i < 14; i++ )
    {
        fscanf( pFile, "%s", Buffer );
        Extra_ReadHexadecimal( &uTruth, Buffer+2, 3 );
        uTruth = uTruth | (uTruth << 8) | (uTruth << 16) | (uTruth << 24);
        Ivy_TruthTestOne( uTruth );
    }
    fclose( pFile );
}

void Ivy_TruthTest5()
{
    FILE * pFile;
    char Buffer[100];
    unsigned uTruth;
    int i;

//    pFile = fopen( "npn4.txt", "r" );
//    for ( i = 0; i < 222; i++ )
    pFile = fopen( "npn5.txt", "r" );
    for ( i = 0; i < 616126; i++ )
    {
        fscanf( pFile, "%s", Buffer );
//        Extra_ReadHexadecimal( &uTruth, Buffer+2, 4 );
        Extra_ReadHexadecimal( &uTruth, Buffer+2, 5 );
//        uTruth |= (uTruth << 16);
//        uTruth = ~uTruth;
        Ivy_TruthTestOne( uTruth );
    }
    fclose( pFile );
}

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