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/**CFile****************************************************************
FileName [abcSat.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Procedures to solve the miter using the internal SAT solver.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcSat.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abc.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static void Abc_NodeAddClauses( solver * pSat, char * pSop0, char * pSop1, Abc_Obj_t * pNode, Vec_Int_t * vVars );
static void Abc_NodeAddClausesTop( solver * pSat, Abc_Obj_t * pNode, Vec_Int_t * vVars );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Attempts to solve the miter using an internal SAT solver.]
Description [Returns 1 if the miter is SAT.]
SideEffects []
SeeAlso []
***********************************************************************/
bool Abc_NtkMiterSat( Abc_Ntk_t * pNtk, int fVerbose )
{
solver * pSat;
lbool status;
int clk;
assert( Abc_NtkIsBddLogic(pNtk) );
assert( Abc_NtkLatchNum(pNtk) == 0 );
if ( Abc_NtkPoNum(pNtk) > 1 )
fprintf( stdout, "Warning: The miter has more than 1 output. SAT will try to prove all of them.\n" );
// load clauses into the solver
clk = clock();
pSat = Abc_NtkMiterSatCreate( pNtk );
// printf( "Created SAT problem with %d variable and %d clauses. ",
// solver_nvars(pSat), solver_nclauses(pSat) );
// PRT( "Time", clock() - clk );
// simplify the problem
clk = clock();
status = solver_simplify(pSat);
// printf( "Simplified the problem to %d variables and %d clauses. ",
// solver_nvars(pSat), solver_nclauses(pSat) );
// PRT( "Time", clock() - clk );
if ( status == l_False )
{
solver_delete( pSat );
printf( "The problem is UNSAT after simplification.\n" );
return 0;
}
// solve the miter
clk = clock();
if ( fVerbose )
pSat->verbosity = 1;
status = solver_solve( pSat, NULL, NULL );
// if ( fVerbose )
// {
printf( "The problem is %5s. ", (status == l_True)? "SAT" : "UNSAT" );
PRT( "SAT solver time", clock() - clk );
// }
// free the solver
solver_delete( pSat );
return status == l_True;
}
/**Function*************************************************************
Synopsis [Sets up the SAT solver.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
solver * Abc_NtkMiterSatCreate( Abc_Ntk_t * pNtk )
{
solver * pSat;
Extra_MmFlex_t * pMmFlex;
Abc_Obj_t * pNode;
Vec_Str_t * vCube;
Vec_Int_t * vVars;
char * pSop0, * pSop1;
int i;
assert( Abc_NtkIsBddLogic(pNtk) );
// start the data structures
pSat = solver_new();
pMmFlex = Extra_MmFlexStart();
vCube = Vec_StrAlloc( 100 );
vVars = Vec_IntAlloc( 100 );
// add clauses for each internal nodes
Abc_NtkForEachNode( pNtk, pNode, i )
{
// derive SOPs for both phases of the node
Abc_NodeBddToCnf( pNode, pMmFlex, vCube, &pSop0, &pSop1 );
// add the clauses to the solver
Abc_NodeAddClauses( pSat, pSop0, pSop1, pNode, vVars );
}
// add clauses for each PO
Abc_NtkForEachPo( pNtk, pNode, i )
Abc_NodeAddClausesTop( pSat, pNode, vVars );
// delete
Vec_StrFree( vCube );
Vec_IntFree( vVars );
Extra_MmFlexStop( pMmFlex, 0 );
return pSat;
}
/**Function*************************************************************
Synopsis [Adds clauses for the internal node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeAddClauses( solver * pSat, char * pSop0, char * pSop1, Abc_Obj_t * pNode, Vec_Int_t * vVars )
{
Abc_Obj_t * pFanin;
int i, c, nFanins;
char * pCube;
nFanins = Abc_ObjFaninNum( pNode );
assert( nFanins == Abc_SopGetVarNum( pSop0 ) );
// add clauses for the negative phase
for ( c = 0; ; c++ )
{
// get the cube
pCube = pSop0 + c * (nFanins + 3);
if ( *pCube == 0 )
break;
// add the clause
vVars->nSize = 0;
Abc_ObjForEachFanin( pNode, pFanin, i )
{
if ( pCube[i] == '0' )
Vec_IntPush( vVars, toLit(pFanin->Id) );
else if ( pCube[i] == '1' )
Vec_IntPush( vVars, neg(toLit(pFanin->Id)) );
}
Vec_IntPush( vVars, neg(toLit(pNode->Id)) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
}
// add clauses for the positive phase
for ( c = 0; ; c++ )
{
// get the cube
pCube = pSop1 + c * (nFanins + 3);
if ( *pCube == 0 )
break;
// add the clause
vVars->nSize = 0;
Abc_ObjForEachFanin( pNode, pFanin, i )
{
if ( pCube[i] == '0' )
Vec_IntPush( vVars, toLit(pFanin->Id) );
else if ( pCube[i] == '1' )
Vec_IntPush( vVars, neg(toLit(pFanin->Id)) );
}
Vec_IntPush( vVars, toLit(pNode->Id) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
}
}
/**Function*************************************************************
Synopsis [Adds clauses for the PO node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeAddClausesTop( solver * pSat, Abc_Obj_t * pNode, Vec_Int_t * vVars )
{
Abc_Obj_t * pFanin;
pFanin = Abc_ObjFanin0(pNode);
if ( Abc_ObjFaninC0(pNode) )
{
vVars->nSize = 0;
Vec_IntPush( vVars, toLit(pFanin->Id) );
Vec_IntPush( vVars, toLit(pNode->Id) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
vVars->nSize = 0;
Vec_IntPush( vVars, neg(toLit(pFanin->Id)) );
Vec_IntPush( vVars, neg(toLit(pNode->Id)) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
}
else
{
vVars->nSize = 0;
Vec_IntPush( vVars, neg(toLit(pFanin->Id)) );
Vec_IntPush( vVars, toLit(pNode->Id) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
vVars->nSize = 0;
Vec_IntPush( vVars, toLit(pFanin->Id) );
Vec_IntPush( vVars, neg(toLit(pNode->Id)) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
}
vVars->nSize = 0;
Vec_IntPush( vVars, toLit(pNode->Id) );
solver_addclause( pSat, vVars->pArray, vVars->pArray + vVars->nSize );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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