/**CFile****************************************************************
FileName [cnfWrite.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [AIG-to-CNF conversion.]
Synopsis []
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - April 28, 2007.]
Revision [$Id: cnfWrite.c,v 1.00 2007/04/28 00:00:00 alanmi Exp $]
***********************************************************************/
#include "cnf.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Derives CNF mapping.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Cnf_ManWriteCnfMapping( Cnf_Man_t * p, Vec_Ptr_t * vMapped )
{
Vec_Int_t * vResult;
Aig_Obj_t * pObj;
Cnf_Cut_t * pCut;
int i, k, nOffset;
nOffset = Aig_ManObjNumMax(p->pManAig);
vResult = Vec_IntStart( nOffset );
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
{
assert( Aig_ObjIsNode(pObj) );
pCut = Cnf_ObjBestCut( pObj );
assert( pCut->nFanins < 5 );
Vec_IntWriteEntry( vResult, Aig_ObjId(pObj), nOffset );
Vec_IntPush( vResult, *Cnf_CutTruth(pCut) );
for ( k = 0; k < pCut->nFanins; k++ )
Vec_IntPush( vResult, pCut->pFanins[k] );
for ( ; k < 4; k++ )
Vec_IntPush( vResult, -1 );
nOffset += 5;
}
return vResult;
}
/**Function*************************************************************
Synopsis [Writes the cover into the array.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Cnf_SopConvertToVector( char * pSop, int nCubes, Vec_Int_t * vCover )
{
int Lits[4], Cube, iCube, i, b;
Vec_IntClear( vCover );
for ( i = 0; i < nCubes; i++ )
{
Cube = pSop[i];
for ( b = 0; b < 4; b++ )
{
if ( Cube % 3 == 0 )
Lits[b] = 1;
else if ( Cube % 3 == 1 )
Lits[b] = 2;
else
Lits[b] = 0;
Cube = Cube / 3;
}
iCube = 0;
for ( b = 0; b < 4; b++ )
iCube = (iCube << 2) | Lits[b];
Vec_IntPush( vCover, iCube );
}
}
/**Function*************************************************************
Synopsis [Returns the number of literals in the SOP.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Cnf_SopCountLiterals( char * pSop, int nCubes )
{
int nLits = 0, Cube, i, b;
for ( i = 0; i < nCubes; i++ )
{
Cube = pSop[i];
for ( b = 0; b < 4; b++ )
{
if ( Cube % 3 != 2 )
nLits++;
Cube = Cube / 3;
}
}
return nLits;
}
/**Function*************************************************************
Synopsis [Returns the number of literals in the SOP.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Cnf_IsopCountLiterals( Vec_Int_t * vIsop, int nVars )
{
int nLits = 0, Cube, i, b;
Vec_IntForEachEntry( vIsop, Cube, i )
{
for ( b = 0; b < nVars; b++ )
{
if ( (Cube & 3) == 1 || (Cube & 3) == 2 )
nLits++;
Cube >>= 2;
}
}
return nLits;
}
/**Function*************************************************************
Synopsis [Writes the cube and returns the number of literals in it.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Cnf_IsopWriteCube( int Cube, int nVars, int * pVars, int * pLiterals )
{
int nLits = nVars, b;
for ( b = 0; b < nVars; b++ )
{
if ( (Cube & 3) == 1 ) // value 0 --> write positive literal
*pLiterals++ = 2 * pVars[b];
else if ( (Cube & 3) == 2 ) // value 1 --> write negative literal
*pLiterals++ = 2 * pVars[b] + 1;
else
nLits--;
Cube >>= 2;
}
return nLits;
}
/**Function*************************************************************
Synopsis [Derives CNF for the mapping.]
Description [The last argument shows the number of last outputs
of the manager, which will not be converted into clauses but the
new variables for which will be introduced.]
SideEffects []
SeeAlso []
***********************************************************************/
Cnf_Dat_t * Cnf_ManWriteCnf( Cnf_Man_t * p, Vec_Ptr_t * vMapped, int nOutputs )
{
int fChangeVariableOrder = 0; // should be set to 0 to improve performance
Aig_Obj_t * pObj;
Cnf_Dat_t * pCnf;
Cnf_Cut_t * pCut;
Vec_Int_t * vCover, * vSopTemp;
int OutVar, PoVar, pVars[32], * pLits, ** pClas;
unsigned uTruth;
int i, k, nLiterals, nClauses, Cube, Number;
// count the number of literals and clauses
nLiterals = 1 + Aig_ManCoNum( p->pManAig ) + 3 * nOutputs;
nClauses = 1 + Aig_ManCoNum( p->pManAig ) + nOutputs;
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
{
assert( Aig_ObjIsNode(pObj) );
pCut = Cnf_ObjBestCut( pObj );
// positive polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & *Cnf_CutTruth(pCut);
nLiterals += Cnf_SopCountLiterals( p->pSops[uTruth], p->pSopSizes[uTruth] ) + p->pSopSizes[uTruth];
assert( p->pSopSizes[uTruth] >= 0 );
nClauses += p->pSopSizes[uTruth];
}
else
{
nLiterals += Cnf_IsopCountLiterals( pCut->vIsop[1], pCut->nFanins ) + Vec_IntSize(pCut->vIsop[1]);
nClauses += Vec_IntSize(pCut->vIsop[1]);
}
// negative polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & ~*Cnf_CutTruth(pCut);
nLiterals += Cnf_SopCountLiterals( p->pSops[uTruth], p->pSopSizes[uTruth] ) + p->pSopSizes[uTruth];
assert( p->pSopSizes[uTruth] >= 0 );
nClauses += p->pSopSizes[uTruth];
}
else
{
nLiterals += Cnf_IsopCountLiterals( pCut->vIsop[0], pCut->nFanins ) + Vec_IntSize(pCut->vIsop[0]);
nClauses += Vec_IntSize(pCut->vIsop[0]);
}
//printf( "%d ", nClauses-(1 + Aig_ManCoNum( p->pManAig )) );
}
//printf( "\n" );
// allocate CNF
pCnf = ABC_CALLOC( Cnf_Dat_t, 1 );
pCnf->pMan = p->pManAig;
pCnf->nLiterals = nLiterals;
pCnf->nClauses = nClauses;
pCnf->pClauses = ABC_ALLOC( int *, nClauses + 1 );
pCnf->pClauses[0] = ABC_ALLOC( int, nLiterals );
pCnf->pClauses[nClauses] = pCnf->pClauses[0] + nLiterals;
// create room for variable numbers
pCnf->pVarNums = ABC_ALLOC( int, Aig_ManObjNumMax(p->pManAig) );
// memset( pCnf->pVarNums, 0xff, sizeof(int) * Aig_ManObjNumMax(p->pManAig) );
for ( i = 0; i < Aig_ManObjNumMax(p->pManAig); i++ )
pCnf->pVarNums[i] = -1;
if ( !fChangeVariableOrder )
{
// assign variables to the last (nOutputs) POs
Number = 1;
if ( nOutputs )
{
if ( Aig_ManRegNum(p->pManAig) == 0 )
{
assert( nOutputs == Aig_ManCoNum(p->pManAig) );
Aig_ManForEachCo( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
}
else
{
assert( nOutputs == Aig_ManRegNum(p->pManAig) );
Aig_ManForEachLiSeq( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
}
}
// assign variables to the internal nodes
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
// assign variables to the PIs and constant node
Aig_ManForEachCi( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
pCnf->pVarNums[Aig_ManConst1(p->pManAig)->Id] = Number++;
pCnf->nVars = Number;
}
else
{
// assign variables to the last (nOutputs) POs
Number = Aig_ManObjNumMax(p->pManAig) + 1;
pCnf->nVars = Number + 1;
if ( nOutputs )
{
if ( Aig_ManRegNum(p->pManAig) == 0 )
{
assert( nOutputs == Aig_ManCoNum(p->pManAig) );
Aig_ManForEachCo( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number--;
}
else
{
assert( nOutputs == Aig_ManRegNum(p->pManAig) );
Aig_ManForEachLiSeq( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number--;
}
}
// assign variables to the internal nodes
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
pCnf->pVarNums[pObj->Id] = Number--;
// assign variables to the PIs and constant node
Aig_ManForEachCi( p->pManAig, pObj, i )
pCnf->pVarNums[pObj->Id] = Number--;
pCnf->pVarNums[Aig_ManConst1(p->pManAig)->Id] = Number--;
assert( Number >= 0 );
}
// assign the clauses
vSopTemp = Vec_IntAlloc( 1 << 16 );
pLits = pCnf->pClauses[0];
pClas = pCnf->pClauses;
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
{
pCut = Cnf_ObjBestCut( pObj );
// save variables of this cut
OutVar = pCnf->pVarNums[ pObj->Id ];
for ( k = 0; k < (int)pCut->nFanins; k++ )
{
pVars[k] = pCnf->pVarNums[ pCut->pFanins[k] ];
assert( pVars[k] <= Aig_ManObjNumMax(p->pManAig) );
}
// positive polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & *Cnf_CutTruth(pCut);
Cnf_SopConvertToVector( p->pSops[uTruth], p->pSopSizes[uTruth], vSopTemp );
vCover = vSopTemp;
}
else
vCover = pCut->vIsop[1];
Vec_IntForEachEntry( vCover, Cube, k )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
pLits += Cnf_IsopWriteCube( Cube, pCut->nFanins, pVars, pLits );
}
// negative polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & ~*Cnf_CutTruth(pCut);
Cnf_SopConvertToVector( p->pSops[uTruth], p->pSopSizes[uTruth], vSopTemp );
vCover = vSopTemp;
}
else
vCover = pCut->vIsop[0];
Vec_IntForEachEntry( vCover, Cube, k )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
pLits += Cnf_IsopWriteCube( Cube, pCut->nFanins, pVars, pLits );
}
}
Vec_IntFree( vSopTemp );
// write the constant literal
OutVar = pCnf->pVarNums[ Aig_ManConst1(p->pManAig)->Id ];
assert( OutVar <= Aig_ManObjNumMax(p->pManAig) );
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
// write the output literals
Aig_ManForEachCo( p->pManAig, pObj, i )
{
OutVar = pCnf->pVarNums[ Aig_ObjFanin0(pObj)->Id ];
if ( i < Aig_ManCoNum(p->pManAig) - nOutputs )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
}
else
{
PoVar = pCnf->pVarNums[ pObj->Id ];
// first clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar;
*pLits++ = 2 * OutVar + !Aig_ObjFaninC0(pObj);
// second clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar + 1;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
}
}
// verify that the correct number of literals and clauses was written
assert( pLits - pCnf->pClauses[0] == nLiterals );
assert( pClas - pCnf->pClauses == nClauses );
//Cnf_DataPrint( pCnf, 1 );
return pCnf;
}
/**Function*************************************************************
Synopsis [Derives CNF for the mapping.]
Description [Derives CNF with obj IDs as SAT vars and mapping of
objects into clauses (pObj2Clause and pObj2Count).]
SideEffects []
SeeAlso []
***********************************************************************/
Cnf_Dat_t * Cnf_ManWriteCnfOther( Cnf_Man_t * p, Vec_Ptr_t * vMapped )
{
Aig_Obj_t * pObj;
Cnf_Dat_t * pCnf;
Cnf_Cut_t * pCut;
Vec_Int_t * vCover, * vSopTemp;
int OutVar, PoVar, pVars[32], * pLits, ** pClas;
unsigned uTruth;
int i, k, nLiterals, nClauses, Cube;
// count the number of literals and clauses
nLiterals = 1 + 4 * Aig_ManCoNum( p->pManAig );
nClauses = 1 + 2 * Aig_ManCoNum( p->pManAig );
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
{
assert( Aig_ObjIsNode(pObj) );
pCut = Cnf_ObjBestCut( pObj );
// positive polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & *Cnf_CutTruth(pCut);
nLiterals += Cnf_SopCountLiterals( p->pSops[uTruth], p->pSopSizes[uTruth] ) + p->pSopSizes[uTruth];
assert( p->pSopSizes[uTruth] >= 0 );
nClauses += p->pSopSizes[uTruth];
}
else
{
nLiterals += Cnf_IsopCountLiterals( pCut->vIsop[1], pCut->nFanins ) + Vec_IntSize(pCut->vIsop[1]);
nClauses += Vec_IntSize(pCut->vIsop[1]);
}
// negative polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & ~*Cnf_CutTruth(pCut);
nLiterals += Cnf_SopCountLiterals( p->pSops[uTruth], p->pSopSizes[uTruth] ) + p->pSopSizes[uTruth];
assert( p->pSopSizes[uTruth] >= 0 );
nClauses += p->pSopSizes[uTruth];
}
else
{
nLiterals += Cnf_IsopCountLiterals( pCut->vIsop[0], pCut->nFanins ) + Vec_IntSize(pCut->vIsop[0]);
nClauses += Vec_IntSize(pCut->vIsop[0]);
}
}
// allocate CNF
pCnf = ABC_CALLOC( Cnf_Dat_t, 1 );
pCnf->pMan = p->pManAig;
pCnf->nLiterals = nLiterals;
pCnf->nClauses = nClauses;
pCnf->pClauses = ABC_ALLOC( int *, nClauses + 1 );
pCnf->pClauses[0] = ABC_ALLOC( int, nLiterals );
pCnf->pClauses[nClauses] = pCnf->pClauses[0] + nLiterals;
// create room for variable numbers
pCnf->pObj2Clause = ABC_ALLOC( int, Aig_ManObjNumMax(p->pManAig) );
pCnf->pObj2Count = ABC_ALLOC( int, Aig_ManObjNumMax(p->pManAig) );
for ( i = 0; i < Aig_ManObjNumMax(p->pManAig); i++ )
pCnf->pObj2Clause[i] = pCnf->pObj2Count[i] = -1;
pCnf->nVars = Aig_ManObjNumMax(p->pManAig);
// clear the PI counters
Aig_ManForEachCi( p->pManAig, pObj, i )
pCnf->pObj2Count[pObj->Id] = 0;
// assign the clauses
vSopTemp = Vec_IntAlloc( 1 << 16 );
pLits = pCnf->pClauses[0];
pClas = pCnf->pClauses;
Vec_PtrForEachEntry( Aig_Obj_t *, vMapped, pObj, i )
{
// remember the starting clause
pCnf->pObj2Clause[pObj->Id] = pClas - pCnf->pClauses;
pCnf->pObj2Count[pObj->Id] = 0;
// get the best cut
pCut = Cnf_ObjBestCut( pObj );
// save variables of this cut
OutVar = pObj->Id;
for ( k = 0; k < (int)pCut->nFanins; k++ )
{
pVars[k] = pCut->pFanins[k];
assert( pVars[k] <= Aig_ManObjNumMax(p->pManAig) );
}
// positive polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & *Cnf_CutTruth(pCut);
Cnf_SopConvertToVector( p->pSops[uTruth], p->pSopSizes[uTruth], vSopTemp );
vCover = vSopTemp;
}
else
vCover = pCut->vIsop[1];
Vec_IntForEachEntry( vCover, Cube, k )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
pLits += Cnf_IsopWriteCube( Cube, pCut->nFanins, pVars, pLits );
}
pCnf->pObj2Count[pObj->Id] += Vec_IntSize(vCover);
// negative polarity of the cut
if ( pCut->nFanins < 5 )
{
uTruth = 0xFFFF & ~*Cnf_CutTruth(pCut);
Cnf_SopConvertToVector( p->pSops[uTruth], p->pSopSizes[uTruth], vSopTemp );
vCover = vSopTemp;
}
else
vCover = pCut->vIsop[0];
Vec_IntForEachEntry( vCover, Cube, k )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
pLits += Cnf_IsopWriteCube( Cube, pCut->nFanins, pVars, pLits );
}
pCnf->pObj2Count[pObj->Id] += Vec_IntSize(vCover);
}
Vec_IntFree( vSopTemp );
// write the output literals
Aig_ManForEachCo( p->pManAig, pObj, i )
{
// remember the starting clause
pCnf->pObj2Clause[pObj->Id] = pClas - pCnf->pClauses;
pCnf->pObj2Count[pObj->Id] = 2;
// get variables
OutVar = Aig_ObjFanin0(pObj)->Id;
PoVar = pObj->Id;
// first clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar;
*pLits++ = 2 * OutVar + !Aig_ObjFaninC0(pObj);
// second clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar + 1;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
}
// remember the starting clause
pCnf->pObj2Clause[Aig_ManConst1(p->pManAig)->Id] = pClas - pCnf->pClauses;
pCnf->pObj2Count[Aig_ManConst1(p->pManAig)->Id] = 1;
// write the constant literal
OutVar = Aig_ManConst1(p->pManAig)->Id;
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
// verify that the correct number of literals and clauses was written
assert( pLits - pCnf->pClauses[0] == nLiterals );
assert( pClas - pCnf->pClauses == nClauses );
//Cnf_DataPrint( pCnf, 1 );
return pCnf;
}
/**Function*************************************************************
Synopsis [Derives a simple CNF for the AIG.]
Description [The last argument lists the number of last outputs
of the manager, which will not be converted into clauses.
New variables will be introduced for these outputs.]
SideEffects []
SeeAlso []
***********************************************************************/
Cnf_Dat_t * Cnf_DeriveSimple( Aig_Man_t * p, int nOutputs )
{
Aig_Obj_t * pObj;
Cnf_Dat_t * pCnf;
int OutVar, PoVar, pVars[32], * pLits, ** pClas;
int i, nLiterals, nClauses, Number;
// count the number of literals and clauses
nLiterals = 1 + 7 * Aig_ManNodeNum(p) + Aig_ManCoNum( p ) + 3 * nOutputs;
nClauses = 1 + 3 * Aig_ManNodeNum(p) + Aig_ManCoNum( p ) + nOutputs;
// allocate CNF
pCnf = ABC_ALLOC( Cnf_Dat_t, 1 );
memset( pCnf, 0, sizeof(Cnf_Dat_t) );
pCnf->pMan = p;
pCnf->nLiterals = nLiterals;
pCnf->nClauses = nClauses;
pCnf->pClauses = ABC_ALLOC( int *, nClauses + 1 );
pCnf->pClauses[0] = ABC_ALLOC( int, nLiterals );
pCnf->pClauses[nClauses] = pCnf->pClauses[0] + nLiterals;
// create room for variable numbers
pCnf->pVarNums = ABC_ALLOC( int, Aig_ManObjNumMax(p) );
// memset( pCnf->pVarNums, 0xff, sizeof(int) * Aig_ManObjNumMax(p) );
for ( i = 0; i < Aig_ManObjNumMax(p); i++ )
pCnf->pVarNums[i] = -1;
// assign variables to the last (nOutputs) POs
Number = 1;
if ( nOutputs )
{
// assert( nOutputs == Aig_ManRegNum(p) );
// Aig_ManForEachLiSeq( p, pObj, i )
// pCnf->pVarNums[pObj->Id] = Number++;
Aig_ManForEachCo( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
}
// assign variables to the internal nodes
Aig_ManForEachNode( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
// assign variables to the PIs and constant node
Aig_ManForEachCi( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
pCnf->pVarNums[Aig_ManConst1(p)->Id] = Number++;
pCnf->nVars = Number;
/*
// print CNF numbers
printf( "SAT numbers of each node:\n" );
Aig_ManForEachObj( p, pObj, i )
printf( "%d=%d ", pObj->Id, pCnf->pVarNums[pObj->Id] );
printf( "\n" );
*/
// assign the clauses
pLits = pCnf->pClauses[0];
pClas = pCnf->pClauses;
Aig_ManForEachNode( p, pObj, i )
{
OutVar = pCnf->pVarNums[ pObj->Id ];
pVars[0] = pCnf->pVarNums[ Aig_ObjFanin0(pObj)->Id ];
pVars[1] = pCnf->pVarNums[ Aig_ObjFanin1(pObj)->Id ];
// positive phase
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
*pLits++ = 2 * pVars[0] + !Aig_ObjFaninC0(pObj);
*pLits++ = 2 * pVars[1] + !Aig_ObjFaninC1(pObj);
// negative phase
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
*pLits++ = 2 * pVars[0] + Aig_ObjFaninC0(pObj);
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
*pLits++ = 2 * pVars[1] + Aig_ObjFaninC1(pObj);
}
// write the constant literal
OutVar = pCnf->pVarNums[ Aig_ManConst1(p)->Id ];
assert( OutVar <= Aig_ManObjNumMax(p) );
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
// write the output literals
Aig_ManForEachCo( p, pObj, i )
{
OutVar = pCnf->pVarNums[ Aig_ObjFanin0(pObj)->Id ];
if ( i < Aig_ManCoNum(p) - nOutputs )
{
*pClas++ = pLits;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
}
else
{
PoVar = pCnf->pVarNums[ pObj->Id ];
// first clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar;
*pLits++ = 2 * OutVar + !Aig_ObjFaninC0(pObj);
// second clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar + 1;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
}
}
// verify that the correct number of literals and clauses was written
assert( pLits - pCnf->pClauses[0] == nLiterals );
assert( pClas - pCnf->pClauses == nClauses );
return pCnf;
}
/**Function*************************************************************
Synopsis [Derives a simple CNF for backward retiming computation.]
Description [The last argument shows the number of last outputs
of the manager, which will not be converted into clauses.
New variables will be introduced for these outputs.]
SideEffects []
SeeAlso []
***********************************************************************/
Cnf_Dat_t * Cnf_DeriveSimpleForRetiming( Aig_Man_t * p )
{
Aig_Obj_t * pObj;
Cnf_Dat_t * pCnf;
int OutVar, PoVar, pVars[32], * pLits, ** pClas;
int i, nLiterals, nClauses, Number;
// count the number of literals and clauses
nLiterals = 1 + 7 * Aig_ManNodeNum(p) + 5 * Aig_ManCoNum(p);
nClauses = 1 + 3 * Aig_ManNodeNum(p) + 3 * Aig_ManCoNum(p);
// allocate CNF
pCnf = ABC_ALLOC( Cnf_Dat_t, 1 );
memset( pCnf, 0, sizeof(Cnf_Dat_t) );
pCnf->pMan = p;
pCnf->nLiterals = nLiterals;
pCnf->nClauses = nClauses;
pCnf->pClauses = ABC_ALLOC( int *, nClauses + 1 );
pCnf->pClauses[0] = ABC_ALLOC( int, nLiterals );
pCnf->pClauses[nClauses] = pCnf->pClauses[0] + nLiterals;
// create room for variable numbers
pCnf->pVarNums = ABC_ALLOC( int, Aig_ManObjNumMax(p) );
// memset( pCnf->pVarNums, 0xff, sizeof(int) * Aig_ManObjNumMax(p) );
for ( i = 0; i < Aig_ManObjNumMax(p); i++ )
pCnf->pVarNums[i] = -1;
// assign variables to the last (nOutputs) POs
Number = 1;
Aig_ManForEachCo( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
// assign variables to the internal nodes
Aig_ManForEachNode( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
// assign variables to the PIs and constant node
Aig_ManForEachCi( p, pObj, i )
pCnf->pVarNums[pObj->Id] = Number++;
pCnf->pVarNums[Aig_ManConst1(p)->Id] = Number++;
pCnf->nVars = Number;
// assign the clauses
pLits = pCnf->pClauses[0];
pClas = pCnf->pClauses;
Aig_ManForEachNode( p, pObj, i )
{
OutVar = pCnf->pVarNums[ pObj->Id ];
pVars[0] = pCnf->pVarNums[ Aig_ObjFanin0(pObj)->Id ];
pVars[1] = pCnf->pVarNums[ Aig_ObjFanin1(pObj)->Id ];
// positive phase
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
*pLits++ = 2 * pVars[0] + !Aig_ObjFaninC0(pObj);
*pLits++ = 2 * pVars[1] + !Aig_ObjFaninC1(pObj);
// negative phase
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
*pLits++ = 2 * pVars[0] + Aig_ObjFaninC0(pObj);
*pClas++ = pLits;
*pLits++ = 2 * OutVar + 1;
*pLits++ = 2 * pVars[1] + Aig_ObjFaninC1(pObj);
}
// write the constant literal
OutVar = pCnf->pVarNums[ Aig_ManConst1(p)->Id ];
assert( OutVar <= Aig_ManObjNumMax(p) );
*pClas++ = pLits;
*pLits++ = 2 * OutVar;
// write the output literals
Aig_ManForEachCo( p, pObj, i )
{
OutVar = pCnf->pVarNums[ Aig_ObjFanin0(pObj)->Id ];
PoVar = pCnf->pVarNums[ pObj->Id ];
// first clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar;
*pLits++ = 2 * OutVar + !Aig_ObjFaninC0(pObj);
// second clause
*pClas++ = pLits;
*pLits++ = 2 * PoVar + 1;
*pLits++ = 2 * OutVar + Aig_ObjFaninC0(pObj);
// final clause (init-state is always 0 -> set the output to 0)
*pClas++ = pLits;
*pLits++ = 2 * PoVar + 1;
}
// verify that the correct number of literals and clauses was written
assert( pLits - pCnf->pClauses[0] == nLiterals );
assert( pClas - pCnf->pClauses == nClauses );
return pCnf;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END