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/**CFile****************************************************************
FileName [abcRefactor.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Resynthesis based on collapsing and refactoring.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcRefactor.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abc.h"
#include "dec.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
typedef struct Abc_ManRef_t_ Abc_ManRef_t;
struct Abc_ManRef_t_
{
// user specified parameters
int nNodeSizeMax; // the limit on the size of the supernode
int nConeSizeMax; // the limit on the size of the containing cone
int fVerbose; // the verbosity flag
// internal data structures
DdManager * dd; // the BDD manager
Vec_Str_t * vCube; // temporary
Vec_Int_t * vForm; // temporary
Vec_Ptr_t * vVisited; // temporary
Vec_Ptr_t * vLeaves; // temporary
// node statistics
int nLastGain;
int nNodesConsidered;
int nNodesRefactored;
int nNodesGained;
// runtime statistics
int timeCut;
int timeBdd;
int timeDcs;
int timeSop;
int timeFact;
int timeEval;
int timeRes;
int timeNtk;
int timeTotal;
};
static void Abc_NtkManRefPrintStats( Abc_ManRef_t * p );
static Abc_ManRef_t * Abc_NtkManRefStart( int nNodeSizeMax, int nConeSizeMax, bool fUseDcs, bool fVerbose );
static void Abc_NtkManRefStop( Abc_ManRef_t * p );
static Dec_Graph_t * Abc_NodeRefactor( Abc_ManRef_t * p, Abc_Obj_t * pNode, Vec_Ptr_t * vFanins, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs incremental resynthesis of the AIG.]
Description [Starting from each node, computes a reconvergence-driven cut,
derives BDD of the cut function, constructs ISOP, factors the ISOP,
and replaces the current implementation of the MFFC of the node by the
new factored form, if the number of AIG nodes is reduced and the total
number of levels of the AIG network is not increated. Returns the
number of AIG nodes saved.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkRefactor( Abc_Ntk_t * pNtk, int nNodeSizeMax, int nConeSizeMax, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose )
{
ProgressBar * pProgress;
Abc_ManRef_t * pManRef;
Abc_ManCut_t * pManCut;
Dec_Graph_t * pFForm;
Vec_Ptr_t * vFanins;
Abc_Obj_t * pNode;
int clk, clkStart = clock();
int i, nNodes;
assert( Abc_NtkIsStrash(pNtk) );
// cleanup the AIG
Abc_AigCleanup(pNtk->pManFunc);
// start the managers
pManCut = Abc_NtkManCutStart( nNodeSizeMax, nConeSizeMax, 2, 1000 );
pManRef = Abc_NtkManRefStart( nNodeSizeMax, nConeSizeMax, fUseDcs, fVerbose );
pManRef->vLeaves = Abc_NtkManCutReadCutLarge( pManCut );
// compute the reverse levels if level update is requested
if ( fUpdateLevel )
Abc_NtkStartReverseLevels( pNtk );
// resynthesize each node once
nNodes = Abc_NtkObjNumMax(pNtk);
pProgress = Extra_ProgressBarStart( stdout, nNodes );
Abc_NtkForEachNode( pNtk, pNode, i )
{
Extra_ProgressBarUpdate( pProgress, i, NULL );
// skip the constant node
if ( Abc_NodeIsConst(pNode) )
continue;
// skip the nodes with many fanouts
if ( Abc_ObjFanoutNum(pNode) > 1000 )
continue;
// stop if all nodes have been tried once
if ( i >= nNodes )
break;
// compute a reconvergence-driven cut
clk = clock();
vFanins = Abc_NodeFindCut( pManCut, pNode, fUseDcs );
pManRef->timeCut += clock() - clk;
// evaluate this cut
clk = clock();
pFForm = Abc_NodeRefactor( pManRef, pNode, vFanins, fUpdateLevel, fUseZeros, fUseDcs, fVerbose );
pManRef->timeRes += clock() - clk;
if ( pFForm == NULL )
continue;
// acceptable replacement found, update the graph
clk = clock();
Dec_GraphUpdateNetwork( pNode, pFForm, fUpdateLevel, pManRef->nLastGain );
pManRef->timeNtk += clock() - clk;
Dec_GraphFree( pFForm );
}
Extra_ProgressBarStop( pProgress );
pManRef->timeTotal = clock() - clkStart;
// print statistics of the manager
if ( fVerbose )
Abc_NtkManRefPrintStats( pManRef );
// delete the managers
Abc_NtkManCutStop( pManCut );
Abc_NtkManRefStop( pManRef );
// put the nodes into the DFS order and reassign their IDs
Abc_NtkReassignIds( pNtk );
// Abc_AigCheckFaninOrder( pNtk->pManFunc );
// fix the levels
if ( fUpdateLevel )
Abc_NtkStopReverseLevels( pNtk );
else
Abc_NtkGetLevelNum( pNtk );
// check
if ( !Abc_NtkCheck( pNtk ) )
{
printf( "Abc_NtkRefactor: The network check has failed.\n" );
return 0;
}
return 1;
}
/**Function*************************************************************
Synopsis [Resynthesizes the node using refactoring.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Dec_Graph_t * Abc_NodeRefactor( Abc_ManRef_t * p, Abc_Obj_t * pNode, Vec_Ptr_t * vFanins, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose )
{
int fVeryVerbose = 0;
Abc_Obj_t * pFanin;
Dec_Graph_t * pFForm;
DdNode * bNodeFunc;
int nNodesSaved, nNodesAdded, i, clk;
char * pSop;
int Required;
Required = fUpdateLevel? Abc_NodeReadRequiredLevel(pNode) : ABC_INFINITY;
p->nNodesConsidered++;
// get the function of the cut
clk = clock();
bNodeFunc = Abc_NodeConeBdd( p->dd, p->dd->vars, pNode, vFanins, p->vVisited ); Cudd_Ref( bNodeFunc );
p->timeBdd += clock() - clk;
// if don't-care are used, transform the function into ISOP
if ( fUseDcs )
{
DdNode * bNodeDc, * bNodeOn, * bNodeOnDc;
int nMints, nMintsDc;
clk = clock();
// get the don't-cares
bNodeDc = Abc_NodeConeDcs( p->dd, p->dd->vars + vFanins->nSize, p->dd->vars, p->vLeaves, vFanins, p->vVisited ); Cudd_Ref( bNodeDc );
nMints = (1 << vFanins->nSize);
nMintsDc = (int)Cudd_CountMinterm( p->dd, bNodeDc, vFanins->nSize );
// printf( "Percentage of minterms = %5.2f.\n", 100.0 * nMintsDc / nMints );
// get the ISF
bNodeOn = Cudd_bddAnd( p->dd, bNodeFunc, Cudd_Not(bNodeDc) ); Cudd_Ref( bNodeOn );
bNodeOnDc = Cudd_bddOr ( p->dd, bNodeFunc, bNodeDc ); Cudd_Ref( bNodeOnDc );
Cudd_RecursiveDeref( p->dd, bNodeFunc );
Cudd_RecursiveDeref( p->dd, bNodeDc );
// get the ISOP
bNodeFunc = Cudd_bddIsop( p->dd, bNodeOn, bNodeOnDc ); Cudd_Ref( bNodeFunc );
Cudd_RecursiveDeref( p->dd, bNodeOn );
Cudd_RecursiveDeref( p->dd, bNodeOnDc );
p->timeDcs += clock() - clk;
}
// always accept the case of constant node
if ( Cudd_IsConstant(bNodeFunc) )
{
p->nLastGain = Abc_NodeMffcSize( pNode );
p->nNodesGained += p->nLastGain;
p->nNodesRefactored++;
Cudd_RecursiveDeref( p->dd, bNodeFunc );
if ( Cudd_IsComplement(bNodeFunc) )
return Dec_GraphCreateConst0();
return Dec_GraphCreateConst1();
}
// get the SOP of the cut
clk = clock();
pSop = Abc_ConvertBddToSop( NULL, p->dd, bNodeFunc, bNodeFunc, vFanins->nSize, p->vCube, -1 );
p->timeSop += clock() - clk;
// get the factored form
clk = clock();
pFForm = Dec_Factor( pSop );
free( pSop );
p->timeFact += clock() - clk;
// mark the fanin boundary
// (can mark only essential fanins, belonging to bNodeFunc!)
Vec_PtrForEachEntry( vFanins, pFanin, i )
pFanin->vFanouts.nSize++;
// label MFFC with current traversal ID
Abc_NtkIncrementTravId( pNode->pNtk );
nNodesSaved = Abc_NodeMffcLabel( pNode );
// unmark the fanin boundary and set the fanins as leaves in the form
Vec_PtrForEachEntry( vFanins, pFanin, i )
{
pFanin->vFanouts.nSize--;
Dec_GraphNode(pFForm, i)->pFunc = pFanin;
}
// detect how many new nodes will be added (while taking into account reused nodes)
clk = clock();
nNodesAdded = Dec_GraphToNetworkCount( pNode, pFForm, nNodesSaved, Required );
p->timeEval += clock() - clk;
// quit if there is no improvement
if ( nNodesAdded == -1 || nNodesAdded == nNodesSaved && !fUseZeros )
{
Cudd_RecursiveDeref( p->dd, bNodeFunc );
Dec_GraphFree( pFForm );
return NULL;
}
// compute the total gain in the number of nodes
p->nLastGain = nNodesSaved - nNodesAdded;
p->nNodesGained += p->nLastGain;
p->nNodesRefactored++;
// report the progress
if ( fVeryVerbose )
{
printf( "Node %6s : ", Abc_ObjName(pNode) );
printf( "Cone = %2d. ", vFanins->nSize );
printf( "BDD = %2d. ", Cudd_DagSize(bNodeFunc) );
printf( "FF = %2d. ", 1 + Dec_GraphNodeNum(pFForm) );
printf( "MFFC = %2d. ", nNodesSaved );
printf( "Add = %2d. ", nNodesAdded );
printf( "GAIN = %2d. ", p->nLastGain );
printf( "\n" );
}
Cudd_RecursiveDeref( p->dd, bNodeFunc );
return pFForm;
}
/**Function*************************************************************
Synopsis [Starts the resynthesis manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_ManRef_t * Abc_NtkManRefStart( int nNodeSizeMax, int nConeSizeMax, bool fUseDcs, bool fVerbose )
{
Abc_ManRef_t * p;
p = ALLOC( Abc_ManRef_t, 1 );
memset( p, 0, sizeof(Abc_ManRef_t) );
p->vCube = Vec_StrAlloc( 100 );
p->vVisited = Vec_PtrAlloc( 100 );
p->nNodeSizeMax = nNodeSizeMax;
p->nConeSizeMax = nConeSizeMax;
p->fVerbose = fVerbose;
// start the BDD manager
if ( fUseDcs )
p->dd = Cudd_Init( p->nNodeSizeMax + p->nConeSizeMax, 0, CUDD_UNIQUE_SLOTS, CUDD_CACHE_SLOTS, 0 );
else
p->dd = Cudd_Init( p->nNodeSizeMax, 0, CUDD_UNIQUE_SLOTS, CUDD_CACHE_SLOTS, 0 );
Cudd_zddVarsFromBddVars( p->dd, 2 );
return p;
}
/**Function*************************************************************
Synopsis [Stops the resynthesis manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkManRefStop( Abc_ManRef_t * p )
{
Extra_StopManager( p->dd );
Vec_PtrFree( p->vVisited );
Vec_StrFree( p->vCube );
free( p );
}
/**Function*************************************************************
Synopsis [Stops the resynthesis manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkManRefPrintStats( Abc_ManRef_t * p )
{
printf( "Refactoring statistics:\n" );
printf( "Nodes considered = %8d.\n", p->nNodesConsidered );
printf( "Nodes refactored = %8d.\n", p->nNodesRefactored );
printf( "Calculated gain = %8d.\n", p->nNodesGained );
PRT( "Cuts ", p->timeCut );
PRT( "Resynthesis", p->timeRes );
PRT( " BDD ", p->timeBdd );
PRT( " DCs ", p->timeDcs );
PRT( " SOP ", p->timeSop );
PRT( " FF ", p->timeFact );
PRT( " Eval ", p->timeEval );
PRT( "AIG update ", p->timeNtk );
PRT( "TOTAL ", p->timeTotal );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
