/**CFile**************************************************************** FileName [saigSimMv.c] SystemName [ABC: Logic synthesis and verification system.] PackageName [Sequential AIG package.] Synopsis [Multi-valued simulation.] Author [Alan Mishchenko] Affiliation [UC Berkeley] Date [Ver. 1.0. Started - June 20, 2005.] Revision [$Id: saigSimMv.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $] ***********************************************************************/ #include "saig.h" //////////////////////////////////////////////////////////////////////// /// DECLARATIONS /// //////////////////////////////////////////////////////////////////////// #define SAIG_DIFF_VALUES 8 #define SAIG_UNDEF_VALUE 0x1ffffffe //536870910 // old AIG typedef struct Saig_MvObj_t_ Saig_MvObj_t; struct Saig_MvObj_t_ { int iFan0; int iFan1; unsigned Type : 3; unsigned Value : 29; }; // new AIG typedef struct Saig_MvAnd_t_ Saig_MvAnd_t; struct Saig_MvAnd_t_ { int iFan0; int iFan1; int iNext; }; // simulation manager typedef struct Saig_MvMan_t_ Saig_MvMan_t; struct Saig_MvMan_t_ { // user data Aig_Man_t * pAig; // original AIG // parameters int nStatesMax; // maximum number of states int nLevelsMax; // maximum number of levels int nValuesMax; // maximum number of values int nFlops; // number of flops // compacted AIG Saig_MvObj_t * pAigOld; // AIG objects Vec_Ptr_t * vFlops; // collected flops Vec_Ptr_t * vTired; // collected flops int * pTStates; // hash table for states int nTStatesSize; // hash table size Aig_MmFixed_t * pMemStates; // memory for states Vec_Ptr_t * vStates; // reached states int * pRegsUndef; // count the number of undef values int ** pRegsValues; // write the first different values int * nRegsValues; // count the number of different values int nRUndefs; // the number of undef registers int nRValues[SAIG_DIFF_VALUES+1]; // the number of registers with given values // internal AIG Saig_MvAnd_t * pAigNew; // AIG nodes int nObjsAlloc; // the number of objects allocated int nObjs; // the number of objects int nPis; // the number of primary inputs int * pTNodes; // hash table int nTNodesSize; // hash table size unsigned char * pLevels; // levels of AIG nodes }; static inline int Saig_MvObjFaninC0( Saig_MvObj_t * pObj ) { return pObj->iFan0 & 1; } static inline int Saig_MvObjFaninC1( Saig_MvObj_t * pObj ) { return pObj->iFan1 & 1; } static inline int Saig_MvObjFanin0( Saig_MvObj_t * pObj ) { return pObj->iFan0 >> 1; } static inline int Saig_MvObjFanin1( Saig_MvObj_t * pObj ) { return pObj->iFan1 >> 1; } static inline int Saig_MvConst0() { return 1; } static inline int Saig_MvConst1() { return 0; } static inline int Saig_MvConst( int c ) { return !c; } static inline int Saig_MvUndef() { return SAIG_UNDEF_VALUE; } static inline int Saig_MvIsConst0( int iNode ) { return iNode == 1; } static inline int Saig_MvIsConst1( int iNode ) { return iNode == 0; } static inline int Saig_MvIsConst( int iNode ) { return iNode < 2; } static inline int Saig_MvIsUndef( int iNode ) { return iNode == SAIG_UNDEF_VALUE;} static inline int Saig_MvRegular( int iNode ) { return (iNode & ~01); } static inline int Saig_MvNot( int iNode ) { return (iNode ^ 01); } static inline int Saig_MvNotCond( int iNode, int c ) { return (iNode ^ (c)); } static inline int Saig_MvIsComplement( int iNode ) { return (int)(iNode & 01); } static inline int Saig_MvLit2Var( int iNode ) { return (iNode >> 1); } static inline int Saig_MvVar2Lit( int iVar ) { return (iVar << 1); } static inline int Saig_MvLev( Saig_MvMan_t * p, int iNode ) { return p->pLevels[iNode >> 1]; } // iterator over compacted objects #define Saig_MvManForEachObj( pAig, pEntry ) \ for ( pEntry = pAig; pEntry->Type != AIG_OBJ_VOID; pEntry++ ) //////////////////////////////////////////////////////////////////////// /// FUNCTION DEFINITIONS /// //////////////////////////////////////////////////////////////////////// /**Function************************************************************* Synopsis [Creates reduced manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ Saig_MvObj_t * Saig_ManCreateReducedAig( Aig_Man_t * p, Vec_Ptr_t ** pvFlops ) { Saig_MvObj_t * pAig, * pEntry; Aig_Obj_t * pObj; int i; *pvFlops = Vec_PtrAlloc( Aig_ManRegNum(p) ); pAig = ABC_CALLOC( Saig_MvObj_t, Aig_ManObjNumMax(p)+1 ); Aig_ManForEachObj( p, pObj, i ) { pEntry = pAig + i; pEntry->Type = pObj->Type; if ( Aig_ObjIsPi(pObj) || i == 0 ) { if ( Saig_ObjIsLo(p, pObj) ) { pEntry->iFan0 = (Saig_ObjLoToLi(p, pObj)->Id << 1); pEntry->iFan1 = -1; Vec_PtrPush( *pvFlops, pEntry ); } continue; } pEntry->iFan0 = (Aig_ObjFaninId0(pObj) << 1) | Aig_ObjFaninC0(pObj); if ( Aig_ObjIsPo(pObj) ) continue; assert( Aig_ObjIsNode(pObj) ); pEntry->iFan1 = (Aig_ObjFaninId1(pObj) << 1) | Aig_ObjFaninC1(pObj); } pEntry = pAig + Aig_ManObjNumMax(p); pEntry->Type = AIG_OBJ_VOID; return pAig; } /**Function************************************************************* Synopsis [Creates a new node.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int Saig_MvCreateObj( Saig_MvMan_t * p, int iFan0, int iFan1 ) { Saig_MvAnd_t * pNode; if ( p->nObjs == p->nObjsAlloc ) { p->pAigNew = ABC_REALLOC( Saig_MvAnd_t, p->pAigNew, 2*p->nObjsAlloc ); p->pLevels = ABC_REALLOC( unsigned char, p->pLevels, 2*p->nObjsAlloc ); p->nObjsAlloc *= 2; } pNode = p->pAigNew + p->nObjs; pNode->iFan0 = iFan0; pNode->iFan1 = iFan1; pNode->iNext = 0; if ( iFan0 || iFan1 ) p->pLevels[p->nObjs] = 1 + ABC_MAX( Saig_MvLev(p, iFan0), Saig_MvLev(p, iFan1) ); else p->pLevels[p->nObjs] = 0, p->nPis++; return p->nObjs++; } /**Function************************************************************* Synopsis [Creates multi-valued simulation manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ Saig_MvMan_t * Saig_MvManStart( Aig_Man_t * pAig ) { Saig_MvMan_t * p; int i; assert( Aig_ManRegNum(pAig) > 0 ); p = (Saig_MvMan_t *)ABC_ALLOC( Saig_MvMan_t, 1 ); memset( p, 0, sizeof(Saig_MvMan_t) ); // set parameters p->pAig = pAig; p->nStatesMax = 200; p->nLevelsMax = 4; p->nValuesMax = SAIG_DIFF_VALUES; p->nFlops = Aig_ManRegNum(pAig); // compacted AIG p->pAigOld = Saig_ManCreateReducedAig( pAig, &p->vFlops ); p->nTStatesSize = Aig_PrimeCudd( p->nStatesMax ); p->pTStates = ABC_CALLOC( int, p->nTStatesSize ); p->pMemStates = Aig_MmFixedStart( sizeof(int) * (p->nFlops+1), p->nStatesMax ); p->vStates = Vec_PtrAlloc( p->nStatesMax ); Vec_PtrPush( p->vStates, NULL ); p->pRegsUndef = ABC_CALLOC( int, p->nFlops ); p->pRegsValues = ABC_ALLOC( int *, p->nFlops ); p->pRegsValues[0] = ABC_ALLOC( int, p->nValuesMax * p->nFlops ); for ( i = 1; i < p->nFlops; i++ ) p->pRegsValues[i] = p->pRegsValues[i-1] + p->nValuesMax; p->nRegsValues = ABC_CALLOC( int, p->nFlops ); p->vTired = Vec_PtrAlloc( 100 ); // internal AIG p->nObjsAlloc = 1000000; p->pAigNew = ABC_ALLOC( Saig_MvAnd_t, p->nObjsAlloc ); p->nTNodesSize = Aig_PrimeCudd( p->nObjsAlloc / 3 ); p->pTNodes = ABC_CALLOC( int, p->nTNodesSize ); p->pLevels = ABC_ALLOC( unsigned char, p->nObjsAlloc ); Saig_MvCreateObj( p, 0, 0 ); return p; } /**Function************************************************************* Synopsis [Destroys multi-valued simulation manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void Saig_MvManStop( Saig_MvMan_t * p ) { Aig_MmFixedStop( p->pMemStates, 0 ); Vec_PtrFree( p->vStates ); Vec_PtrFree( p->vFlops ); Vec_PtrFree( p->vTired ); ABC_FREE( p->pRegsValues[0] ); ABC_FREE( p->pRegsValues ); ABC_FREE( p->nRegsValues ); ABC_FREE( p->pRegsUndef ); ABC_FREE( p->pAigOld ); ABC_FREE( p->pTStates ); ABC_FREE( p->pAigNew ); ABC_FREE( p->pTNodes ); ABC_FREE( p->pLevels ); ABC_FREE( p ); } /**Function************************************************************* Synopsis [Hashing the node.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int Saig_MvHash( int iFan0, int iFan1, int TableSize ) { unsigned Key = 0; assert( iFan0 < iFan1 ); Key ^= Saig_MvLit2Var(iFan0) * 7937; Key ^= Saig_MvLit2Var(iFan1) * 2971; Key ^= Saig_MvIsComplement(iFan0) * 911; Key ^= Saig_MvIsComplement(iFan1) * 353; return (int)(Key % TableSize); } /**Function************************************************************* Synopsis [Returns the place where this node is stored (or should be stored).] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int * Saig_MvTableFind( Saig_MvMan_t * p, int iFan0, int iFan1 ) { Saig_MvAnd_t * pEntry; int * pPlace = p->pTNodes + Saig_MvHash( iFan0, iFan1, p->nTNodesSize ); for ( pEntry = (*pPlace)? p->pAigNew + *pPlace : NULL; pEntry; pPlace = &pEntry->iNext, pEntry = (*pPlace)? p->pAigNew + *pPlace : NULL ) if ( pEntry->iFan0 == iFan0 && pEntry->iFan1 == iFan1 ) break; return pPlace; } /**Function************************************************************* Synopsis [Performs an AND-operation.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int Saig_MvAnd( Saig_MvMan_t * p, int iFan0, int iFan1 ) { if ( iFan0 == iFan1 ) return iFan0; if ( iFan0 == Saig_MvNot(iFan1) ) return Saig_MvConst0(); if ( Saig_MvIsConst(iFan0) ) return Saig_MvIsConst1(iFan0) ? iFan1 : Saig_MvConst0(); if ( Saig_MvIsConst(iFan1) ) return Saig_MvIsConst1(iFan1) ? iFan0 : Saig_MvConst0(); if ( Saig_MvIsUndef(iFan0) || Saig_MvIsUndef(iFan1) ) return Saig_MvUndef(); if ( Saig_MvLev(p, iFan0) >= p->nLevelsMax || Saig_MvLev(p, iFan1) >= p->nLevelsMax ) return Saig_MvUndef(); // return Saig_MvUndef(); if ( iFan0 > iFan1 ) { int Temp = iFan0; iFan0 = iFan1; iFan1 = Temp; } { int * pPlace; pPlace = Saig_MvTableFind( p, iFan0, iFan1 ); if ( *pPlace == 0 ) *pPlace = Saig_MvCreateObj( p, iFan0, iFan1 ); return Saig_MvVar2Lit( *pPlace ); } } /**Function************************************************************* Synopsis [Propagates one edge.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int Saig_MvSimulateValue0( Saig_MvObj_t * pAig, Saig_MvObj_t * pObj ) { Saig_MvObj_t * pObj0 = pAig + Saig_MvObjFanin0(pObj); if ( Saig_MvIsUndef( pObj0->Value ) ) return Saig_MvUndef(); return Saig_MvNotCond( pObj0->Value, Saig_MvObjFaninC0(pObj) ); } static inline int Saig_MvSimulateValue1( Saig_MvObj_t * pAig, Saig_MvObj_t * pObj ) { Saig_MvObj_t * pObj1 = pAig + Saig_MvObjFanin1(pObj); if ( Saig_MvIsUndef( pObj1->Value ) ) return Saig_MvUndef(); return Saig_MvNotCond( pObj1->Value, Saig_MvObjFaninC1(pObj) ); } /**Function************************************************************* Synopsis [Performs one iteration of simulation.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void Saig_MvSimulateFrame( Saig_MvMan_t * p, int fFirst ) { int fPrintState = 0; Saig_MvObj_t * pEntry; int i, NewValue; Saig_MvManForEachObj( p->pAigOld, pEntry ) { if ( pEntry->Type == AIG_OBJ_AND ) { pEntry->Value = Saig_MvAnd( p, Saig_MvSimulateValue0(p->pAigOld, pEntry), Saig_MvSimulateValue1(p->pAigOld, pEntry) ); /* printf( "%d = %d%s * %d%s --> %d\n", pEntry - p->pAigOld, Saig_MvObjFanin0(pEntry), Saig_MvObjFaninC0(pEntry)? "-":"+", Saig_MvObjFanin1(pEntry), Saig_MvObjFaninC1(pEntry)? "-":"+", pEntry->Value ); */ } else if ( pEntry->Type == AIG_OBJ_PO ) pEntry->Value = Saig_MvSimulateValue0(p->pAigOld, pEntry); else if ( pEntry->Type == AIG_OBJ_PI ) { if ( pEntry->iFan1 == 0 ) // true PI pEntry->Value = Saig_MvVar2Lit( Saig_MvCreateObj( p, 0, 0 ) ); // else if ( fFirst ) // register output // pEntry->Value = Saig_MvConst0(); // else // pEntry->Value = Saig_MvSimulateValue0(p->pAigOld, pEntry); } else if ( pEntry->Type == AIG_OBJ_CONST1 ) pEntry->Value = Saig_MvConst1(); else if ( pEntry->Type != AIG_OBJ_NONE ) assert( 0 ); } Vec_PtrClear( p->vTired ); Vec_PtrForEachEntry( p->vFlops, pEntry, i ) { NewValue = Saig_MvSimulateValue0(p->pAigOld, pEntry); if ( NewValue != (int)pEntry->Value ) Vec_PtrPush( p->vTired, pEntry ); pEntry->Value = NewValue; if ( !fPrintState ) continue; if ( pEntry->Value == 536870910 ) printf( "* " ); else printf( "%d ", pEntry->Value ); } if ( fPrintState ) printf( "\n" ); } /**Function************************************************************* Synopsis [Computes hash value of the node using its simulation info.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ int Saig_MvSimHash( int * pState, int nFlops, int TableSize ) { static int s_SPrimes[128] = { 1009, 1049, 1093, 1151, 1201, 1249, 1297, 1361, 1427, 1459, 1499, 1559, 1607, 1657, 1709, 1759, 1823, 1877, 1933, 1997, 2039, 2089, 2141, 2213, 2269, 2311, 2371, 2411, 2467, 2543, 2609, 2663, 2699, 2741, 2797, 2851, 2909, 2969, 3037, 3089, 3169, 3221, 3299, 3331, 3389, 3461, 3517, 3557, 3613, 3671, 3719, 3779, 3847, 3907, 3943, 4013, 4073, 4129, 4201, 4243, 4289, 4363, 4441, 4493, 4549, 4621, 4663, 4729, 4793, 4871, 4933, 4973, 5021, 5087, 5153, 5227, 5281, 5351, 5417, 5471, 5519, 5573, 5651, 5693, 5749, 5821, 5861, 5923, 6011, 6073, 6131, 6199, 6257, 6301, 6353, 6397, 6481, 6563, 6619, 6689, 6737, 6803, 6863, 6917, 6977, 7027, 7109, 7187, 7237, 7309, 7393, 7477, 7523, 7561, 7607, 7681, 7727, 7817, 7877, 7933, 8011, 8039, 8059, 8081, 8093, 8111, 8123, 8147 }; unsigned uHash = 0; int i; for ( i = 0; i < nFlops; i++ ) uHash ^= pState[i] * s_SPrimes[i & 0x7F]; return (int)(uHash % TableSize); } /**Function************************************************************* Synopsis [Returns the place where this state is stored (or should be stored).] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ static inline int * Saig_MvSimTableFind( Saig_MvMan_t * p, int * pState ) { int * pEntry; int * pPlace = p->pTStates + Saig_MvSimHash( pState+1, p->nFlops, p->nTStatesSize ); for ( pEntry = (*pPlace)? Vec_PtrEntry(p->vStates, *pPlace) : NULL; pEntry; pPlace = pEntry, pEntry = (*pPlace)? Vec_PtrEntry(p->vStates, *pPlace) : NULL ) if ( memcmp( pEntry+1, pState+1, sizeof(int)*p->nFlops ) == 0 ) break; return pPlace; } /**Function************************************************************* Synopsis [Saves current state.] Description [Returns -1 if there is no fixed point.] SideEffects [] SeeAlso [] ***********************************************************************/ int Saig_MvSaveState( Saig_MvMan_t * p, int * piReg ) { Saig_MvObj_t * pEntry; int i, k, * pState, * pPlace, nMaxUndefs = 0; int iTimesOld, iTimesNew; *piReg = -1; pState = (int *)Aig_MmFixedEntryFetch( p->pMemStates ); pState[0] = 0; Vec_PtrForEachEntry( p->vFlops, pEntry, i ) { iTimesOld = p->nRegsValues[i]; // count the number of different def values if ( !Saig_MvIsUndef( pEntry->Value ) && p->nRegsValues[i] < p->nValuesMax ) { for ( k = 0; k < p->nRegsValues[i]; k++ ) if ( p->pRegsValues[i][k] == (int)pEntry->Value ) break; if ( k == p->nRegsValues[i] ) p->pRegsValues[i][ p->nRegsValues[i]++ ] = pEntry->Value; } else // retire this register (consider moving this up!) { pEntry->Value = Saig_MvUndef(); p->nRegsValues[i] = SAIG_DIFF_VALUES+1; } iTimesNew = p->nRegsValues[i]; // count the number of times if ( iTimesOld != iTimesNew ) { if ( iTimesOld > 0 ) p->nRValues[iTimesOld]--; if ( iTimesNew <= SAIG_DIFF_VALUES ) p->nRValues[iTimesNew]++; } // count the number of undef values if ( Saig_MvIsUndef( pEntry->Value ) ) { if ( p->pRegsUndef[i]++ == 0 ) p->nRUndefs++; } // find def reg with the max number of undef values if ( nMaxUndefs < p->pRegsUndef[i] ) { nMaxUndefs = p->pRegsUndef[i]; *piReg = i; } // remember state pState[i+1] = pEntry->Value; // if ( pEntry->Value == 536870910 ) // printf( "* " ); // else // printf( "%d ", pEntry->Value ); } //printf( "\n" ); pPlace = Saig_MvSimTableFind( p, pState ); if ( *pPlace ) return *pPlace; *pPlace = Vec_PtrSize( p->vStates ); Vec_PtrPush( p->vStates, pState ); return -1; } /**Function************************************************************* Synopsis [Performs multi-valued simulation.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void Saig_MvManPostProcess( Saig_MvMan_t * p, int iState ) { Saig_MvObj_t * pEntry; int i, k, j, nTotal = 0, * pState, Counter = 0, iFlop; Vec_Int_t * vUniques = Vec_IntAlloc( 100 ); Vec_Int_t * vCounter = Vec_IntAlloc( 100 ); // count registers that never became undef Vec_PtrForEachEntry( p->vFlops, pEntry, i ) if ( p->pRegsUndef[i] == 0 ) nTotal++; printf( "The number of registers that never became undef = %d. (Total = %d.)\n", nTotal, p->nFlops ); Vec_PtrForEachEntry( p->vFlops, pEntry, i ) { if ( p->pRegsUndef[i] ) continue; Vec_IntForEachEntry( vUniques, iFlop, k ) { Vec_PtrForEachEntryStart( p->vStates, pState, j, 1 ) if ( pState[iFlop+1] != pState[i+1] ) break; if ( j == Vec_PtrSize(p->vStates) ) { Vec_IntAddToEntry( vCounter, k, 1 ); break; } } if ( k == Vec_IntSize(vUniques) ) { Vec_IntPush( vUniques, i ); Vec_IntPush( vCounter, 1 ); } } Vec_IntForEachEntry( vUniques, iFlop, i ) { printf( "FLOP %5d : (%3d) ", iFlop, Vec_IntEntry(vCounter,i) ); /* for ( k = 0; k < p->nRegsValues[iFlop]; k++ ) if ( p->pRegsValues[iFlop][k] == 536870910 ) printf( "* " ); else printf( "%d ", p->pRegsValues[iFlop][k] ); printf( "\n" ); */ Vec_PtrForEachEntryStart( p->vStates, pState, k, 1 ) { if ( k == iState+1 ) printf( " # " ); if ( pState[iFlop+1] == 536870910 ) printf( "*" ); else printf( "%d", pState[iFlop+1] ); } printf( "\n" ); // if ( ++Counter == 10 ) // break; } Vec_IntFree( vUniques ); Vec_IntFree( vCounter ); } /**Function************************************************************* Synopsis [Performs multi-valued simulation.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ int Saig_MvManSimulate( Aig_Man_t * pAig, int fVerbose ) { Saig_MvMan_t * p; Saig_MvObj_t * pEntry; int f, i, k, iRegMax, iState, clk = clock(); // start the manager p = Saig_MvManStart( pAig ); ABC_PRT( "Constructing the problem", clock() - clk ); clk = clock(); // initiliaze registers Vec_PtrForEachEntry( p->vFlops, pEntry, i ) { pEntry->Value = Saig_MvConst0(); if ( pEntry->iFan0 == 1 ) printf( "Constant value %d\n", i ); } Saig_MvSaveState( p, &iRegMax ); // simulate until convergence for ( f = 0; ; f++ ) { /* if ( fVerbose ) { printf( "%3d : ", f+1 ); printf( "*=%6d ", p->nRUndefs ); for ( k = 1; k < SAIG_DIFF_VALUES; k++ ) if ( p->nRValues[k] == 0 ) printf( " " ); else printf( "%d=%6d ", k, p->nRValues[k] ); printf( "aig=%6d", p->nObjs ); printf( "\n" ); } */ Saig_MvSimulateFrame( p, f==0 ); iState = Saig_MvSaveState( p, &iRegMax ); if ( iState >= 0 ) { printf( "Converged after %d frames with lasso in state %d. Cycle = %d.\n", f+1, iState-1, f+2-iState ); printf( "Total number of PIs = %d. AND nodes = %d.\n", p->nPis, p->nObjs - p->nPis ); break; } if ( f >= p->nStatesMax && iRegMax >= 0 ) { /* pEntry = Vec_PtrEntry( p->vFlops, iRegMax ); assert( pEntry->Value != (unsigned)Saig_MvUndef() ); pEntry->Value = Saig_MvUndef(); printf( "Retiring flop %d.\n", iRegMax ); */ // printf( "Retiring %d flops.\n", Vec_PtrSize(p->vTired) ); Vec_PtrForEachEntry( p->vTired, pEntry, k ) pEntry->Value = Saig_MvUndef(); } } ABC_PRT( "Multi-value simulation", clock() - clk ); // implement equivalences Saig_MvManPostProcess( p, iState-1 ); Saig_MvManStop( p ); return 1; } //////////////////////////////////////////////////////////////////////// /// END OF FILE /// ////////////////////////////////////////////////////////////////////////