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|
/**CFile****************************************************************
FileName [sbd.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [SAT-based optimization using internal don't-cares.]
Synopsis []
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: sbd.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "sbdInt.h"
#include "misc/util/utilTruth.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
#define MAX_M 12 // max inputs
#define MAX_N 20 // max nodes
#define MAX_K 6 // max lutsize
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
sat_solver * Sbd_SolverTopo( int M, int N, int K, int pVars[MAX_N][MAX_M+MAX_N][MAX_K] ) // inputs, nodes, lutsize
{
sat_solver * pSat = NULL;
Vec_Int_t * vTemp = Vec_IntAlloc(100);
// assign vars
int RetValue, n, i, j, k, nVars = 0;
for ( n = 0; n < N; n++ )
for ( i = 0; i < M+N; i++ )
for ( k = 0; k < K; k++ )
pVars[n][i][k] = nVars++;
printf( "Number of vars = %d.\n", nVars );
// add constraints
pSat = sat_solver_new();
sat_solver_setnvars( pSat, nVars );
// each node is used
for ( i = 0; i < M+N-1; i++ )
{
Vec_IntClear( vTemp );
for ( n = 0; n < N; n++ )
for ( k = 0; k < K; k++ )
Vec_IntPush( vTemp, Abc_Var2Lit(pVars[n][i][k], 0) );
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntLimit(vTemp) );
assert( RetValue );
}
// each fanin of each node is connected
for ( n = 0; n < N; n++ )
for ( k = 0; k < K; k++ )
{
Vec_IntClear( vTemp );
for ( i = 0; i < M+n; i++ )
Vec_IntPush( vTemp, Abc_Var2Lit(pVars[n][i][k], 0) );
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntLimit(vTemp) );
assert( RetValue );
}
// each fanin is connected once; fanins are ordered; nodes are ordered
for ( n = 0; n < N; n++ )
for ( i = 0; i < M+N; i++ )
for ( k = 0; k < K; k++ )
{
int n2 = n, i2 = i, k2 = k;
for ( n2 = 0; n2 <= n; n2++ )
for ( i2 = i; i2 < M+N; i2++ )
for ( k2 = 0; k2 <= k; k2++ )
{
if ( n2 == n && i2 == i && k2 == k )
continue;
Vec_IntFillTwo( vTemp, 2, Abc_Var2Lit(pVars[n][i][k], 1), Abc_Var2Lit(pVars[n2][i2][k2], 1) );
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntLimit(vTemp) );
assert( RetValue );
}
}
// exclude fanins of two-input nodes
if ( K == 2 )
for ( n = 0; n < N; n++ )
for ( i = M; i < M+N; i++ )
for ( k = 0; k < K; k++ )
{
int k2;
for ( j = 0; j < i; j++ )
for ( k2 = 0; k2 < K; k2++ )
{
Vec_IntClear( vTemp );
Vec_IntPush( vTemp, Abc_Var2Lit(pVars[n][i][k], 1) );
Vec_IntPush( vTemp, Abc_Var2Lit(pVars[n][j][!k], 1) );
Vec_IntPush( vTemp, Abc_Var2Lit(pVars[i-M][j][k2], 1) );
RetValue = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntLimit(vTemp) );
assert( RetValue );
}
}
Vec_IntFree( vTemp );
return pSat;
}
void Sbd_SolverTopoPrint( sat_solver * pSat, int M, int N, int K, int pVars[MAX_N][MAX_M+MAX_N][MAX_K] )
{
int n, i, k;
printf( "Solution:\n" );
printf( " | " );
for ( n = 0; n < N; n++ )
printf( "%2d ", M+n );
printf( "\n" );
for ( i = M+N-2; i >= 0; i-- )
{
printf( "%2d %c | ", i, i < M ? 'i' : ' ' );
for ( n = 0; n < N; n++ )
{
for ( k = 0; k < K; k++ )
printf( "%c", sat_solver_var_value(pSat, pVars[n][i][k]) ? '*' : '.' );
printf( " " );
}
printf( "\n" );
}
}
void Sbd_SolverTopoTest()
{
int M = 4; // 6; // inputs
int N = 4; // 16; // nodes
int K = 2; // 2; // lutsize
int status, v, nVars, nIter, nSols = 0;
int pVars[MAX_N][MAX_M+MAX_N][MAX_K]; // 20 x 32 x 6 = 3840
Vec_Int_t * vLits = Vec_IntAlloc(100);
sat_solver * pSat = Sbd_SolverTopo( M, N, K, pVars );
nVars = sat_solver_nvars( pSat );
for ( nIter = 0; nIter < 1000000; nIter++ )
{
// find onset minterm
status = sat_solver_solve( pSat, NULL, NULL, 0, 0, 0, 0 );
if ( status == l_Undef )
break;
if ( status == l_False )
break;
assert( status == l_True );
nSols++;
// print solution
Sbd_SolverTopoPrint( pSat, M, N, K, pVars );
// remember variable values
Vec_IntClear( vLits );
for ( v = 0; v < nVars; v++ )
if ( sat_solver_var_value(pSat, v) )
Vec_IntPush( vLits, Abc_Var2Lit(v, 1) );
// add breaking clause
status = sat_solver_addclause( pSat, Vec_IntArray(vLits), Vec_IntLimit(vLits) );
if ( status == 0 )
break;
}
printf( "Found %d solutions.\n", nSols );
sat_solver_delete( pSat );
Vec_IntFree( vLits );
}
/**Function*************************************************************
Synopsis [Compute truth table for the given parameter settings.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
word Sbd_SolverTruth( int M, int N, int K, int pLuts[MAX_N][MAX_K], int pValues[MAX_N*((1<<MAX_K)-1)] )
{
word Truths[MAX_M+MAX_N];
int i, k, v, nLutPars = (1 << K) - 1;
assert( M <= 6 );
assert( N <= MAX_N );
for ( i = 0; i < M; i++ )
Truths[i] = s_Truths6[i];
for ( i = 0; i < N; i++ )
{
word Truth = 0, Mint;
for ( k = 1; k <= nLutPars; k++ )
{
if ( !pValues[i*nLutPars+k-1] )
continue;
Mint = ~(word)0;
for ( v = 0; v < K; v++ )
Mint &= ((k >> v) & 1) ? Truths[pLuts[i][v]] : ~Truths[pLuts[i][v]];
Truth |= Mint;
}
Truths[M+i] = Truth;
}
return Truths[M+N-1];
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Sbd_SolverFunc( int M, int N, int K, int pLuts[MAX_N][MAX_K], word TruthInit, int * pValues )
{
int fVerbose = 0;
sat_solver * pSat = NULL;
int pLits[MAX_K+2], pLits2[MAX_K+2], nLits;
int nLutPars = (1 << K) - 1, nVars = N * nLutPars;
int i, k, m, status, iMint, Iter, fCompl = (int)(TruthInit & 1);
word TruthNew, Truth = (TruthInit & 1) ? ~TruthInit : TruthInit;
word Mask = M < 6 ? Abc_Tt6Mask(1 << M) : ~(word)0;
printf( "Number of parameters %d x %d = %d.\n", N, nLutPars, nVars );
// create solver
pSat = sat_solver_new();
sat_solver_setnvars( pSat, nVars );
// start with the last minterm
iMint = (1 << M) - 1;
for ( Iter = 0; Iter < (1 << M); Iter++ )
{
// assign the first intermediate variable
int nVarStart = sat_solver_nvars(pSat);
sat_solver_setnvars( pSat, nVarStart + N - 1 );
// add clauses for nodes
if ( fVerbose )
printf( "\nIter %3d : Minterm %d\n", Iter, iMint );
for ( i = 0; i < N; i++ )
for ( m = 0; m <= nLutPars; m++ )
{
if ( fVerbose )
printf( "i = %d. m = %d.\n", i, m );
// selector variables
nLits = 0;
for ( k = 0; k < K; k++ )
{
if ( pLuts[i][k] >= M )
{
assert( pLuts[i][k] - M < N - 1 );
pLits[nLits] = pLits2[nLits] = Abc_Var2Lit( nVarStart + pLuts[i][k] - M, (m >> k) & 1 );
nLits++;
}
else if ( ((iMint >> pLuts[i][k]) & 1) != ((m >> k) & 1) )
break;
}
if ( k < K )
continue;
// add parameter
if ( m )
{
pLits[nLits] = Abc_Var2Lit( i*nLutPars + m-1, 1 );
pLits2[nLits] = Abc_Var2Lit( i*nLutPars + m-1, 0 );
nLits++;
}
// node variable
if ( i != N - 1 )
{
pLits[nLits] = Abc_Var2Lit( nVarStart + i, 0 );
pLits2[nLits] = Abc_Var2Lit( nVarStart + i, 1 );
nLits++;
}
// add clauses
if ( i != N - 1 || ((TruthInit >> iMint) & 1) != fCompl )
{
status = sat_solver_addclause( pSat, pLits2, pLits2 + nLits );
if ( status == 0 )
{
fCompl = -1;
goto finish;
}
}
if ( (i != N - 1 || ((TruthInit >> iMint) & 1) == fCompl) && m > 0 )
{
status = sat_solver_addclause( pSat, pLits, pLits + nLits );
if ( status == 0 )
{
fCompl = -1;
goto finish;
}
}
}
// run SAT solver
status = sat_solver_solve( pSat, NULL, NULL, 0, 0, 0, 0 );
if ( status == l_Undef )
break;
if ( status == l_False )
{
fCompl = -1;
goto finish;
}
assert( status == l_True );
// collect values
for ( i = 0; i < nVars; i++ )
pValues[i] = sat_solver_var_value(pSat, i);
TruthNew = Sbd_SolverTruth( M, N, K, pLuts, pValues );
if ( fVerbose )
{
for ( i = 0; i < nVars; i++ )
printf( "%d=%d ", i, pValues[i] );
printf( " " );
for ( i = nVars; i < sat_solver_nvars(pSat); i++ )
printf( "%d=%d ", i, sat_solver_var_value(pSat, i) );
printf( "\n" );
Extra_PrintBinary( stdout, (unsigned *)&Truth, (1 << M) ); printf( "\n" );
Extra_PrintBinary( stdout, (unsigned *)&TruthNew, (1 << M) ); printf( "\n" );
}
if ( (Truth & Mask) == (Mask & TruthNew) )
break;
// get new minterm
iMint = Abc_Tt6FirstBit( Truth ^ TruthNew );
}
finish:
printf( "Finished after %d iterations and %d conflicts.\n", Iter, sat_solver_nconflicts(pSat) );
sat_solver_delete( pSat );
return fCompl;
}
void Sbd_SolverFuncTest()
{
// int M = 4; // 6; // inputs
// int N = 3; // 16; // nodes
// int K = 2; // 2; // lutsize
int M = 6; // 6; // inputs
int N = 5; // 16; // nodes
int K = 2; // 2; // lutsize
// word Truth = ~(word)(1 << 0);
word Truth = ~(word)(23423);
int pLuts[MAX_N][MAX_K] = { {0,1}, {2,3}, {4,5}, {6,7}, {8,9} };
int pValues[MAX_N*((1<<MAX_K)-1)];
int i, k, nLutPars = (1 << K) - 1;
int Res = Sbd_SolverFunc( M, N, K, pLuts, Truth, pValues );
if ( Res == -1 )
{
printf( "Solution does not exist.\n" );
return;
}
printf( "Result (compl = %d):\n", Res );
for ( i = 0; i < N; i++ )
{
for ( k = nLutPars-1; k >= 0; k-- )
printf( "%d", pValues[i*nLutPars+k] );
printf( "0\n" );
}
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
|
