diff options
Diffstat (limited to 'src/misc/extra/extraBddCas.c')
| -rw-r--r-- | src/misc/extra/extraBddCas.c | 1235 |
1 files changed, 0 insertions, 1235 deletions
diff --git a/src/misc/extra/extraBddCas.c b/src/misc/extra/extraBddCas.c deleted file mode 100644 index 024e4462..00000000 --- a/src/misc/extra/extraBddCas.c +++ /dev/null @@ -1,1235 +0,0 @@ -/**CFile**************************************************************** - - FileName [extraBddCas.c] - - PackageName [extra] - - Synopsis [Procedures related to LUT cascade synthesis.] - - Author [Alan Mishchenko] - - Affiliation [UC Berkeley] - - Date [Ver. 2.0. Started - September 1, 2003.] - - Revision [$Id: extraBddCas.c,v 1.0 2003/05/21 18:03:50 alanmi Exp $] - -***********************************************************************/ - -#include "extraBdd.h" - -ABC_NAMESPACE_IMPL_START - - -/*---------------------------------------------------------------------------*/ -/* Constant declarations */ -/*---------------------------------------------------------------------------*/ - -/*---------------------------------------------------------------------------*/ -/* Stucture declarations */ -/*---------------------------------------------------------------------------*/ - -/*---------------------------------------------------------------------------*/ -/* Type declarations */ -/*---------------------------------------------------------------------------*/ - -// the table to store cofactor operations -#define _TABLESIZE_COF 51113 -typedef struct -{ - unsigned Sign; - DdNode * Arg1; -} _HashEntry_cof; -_HashEntry_cof HHTable1[_TABLESIZE_COF]; - -// the table to store the result of computation of the number of minterms -#define _TABLESIZE_MINT 15113 -typedef struct -{ - DdNode * Arg1; - unsigned Arg2; - unsigned Res; -} _HashEntry_mint; -_HashEntry_mint HHTable2[_TABLESIZE_MINT]; - -typedef struct -{ - int nEdges; // the number of in-coming edges of the node - DdNode * bSum; // the sum of paths of the incoming edges -} traventry; - -// the signature used for hashing -static unsigned s_Signature = 1; - -static int s_CutLevel = 0; - -/*---------------------------------------------------------------------------*/ -/* Variable declarations */ -/*---------------------------------------------------------------------------*/ - -// because the proposed solution to the optimal encoding problem has exponential complexity -// we limit the depth of the branch and bound procedure to 5 levels -static int s_MaxDepth = 5; - -static int s_nVarsBest; // the number of vars in the best ordering -static int s_VarOrderBest[32]; // storing the best ordering of vars in the "simple encoding" -static int s_VarOrderCur[32]; // storing the current ordering of vars - -// the place to store the supports of the encoded function -static DdNode * s_Field[8][256]; // the size should be K, 2^K, where K is no less than MaxDepth -static DdNode * s_Encoded; // this is the original function -static DdNode * s_VarAll; // the set of all column variables -static int s_MultiStart; // the total number of encoding variables used -// the array field now stores the supports - -static DdNode ** s_pbTemp; // the temporary storage for the columns - -static int s_BackTracks; -static int s_BackTrackLimit = 100; - -static DdNode * s_Terminal; // the terminal value for counting minterms - - -static int s_EncodingVarsLevel; - - -/*---------------------------------------------------------------------------*/ -/* Macro declarations */ -/*---------------------------------------------------------------------------*/ - - -/**AutomaticStart*************************************************************/ - -/*---------------------------------------------------------------------------*/ -/* Static function prototypes */ -/*---------------------------------------------------------------------------*/ - -static DdNode * CreateTheCodes_rec( DdManager * dd, DdNode * bEncoded, int Level, DdNode ** pCVars ); -static void EvaluateEncodings_rec( DdManager * dd, DdNode * bVarsCol, int nVarsCol, int nMulti, int Level ); -// functions called from EvaluateEncodings_rec() -static DdNode * ComputeVarSetAndCountMinterms( DdManager * dd, DdNode * bVars, DdNode * bVarTop, unsigned * Cost ); -static DdNode * ComputeVarSetAndCountMinterms2( DdManager * dd, DdNode * bVars, DdNode * bVarTop, unsigned * Cost ); -unsigned Extra_CountCofactorMinterms( DdManager * dd, DdNode * bFunc, DdNode * bVarsCof, DdNode * bVarsAll ); -static unsigned Extra_CountMintermsSimple( DdNode * bFunc, unsigned max ); - -static void CountNodeVisits_rec( DdManager * dd, DdNode * aFunc, st__table * Visited ); -static void CollectNodesAndComputePaths_rec( DdManager * dd, DdNode * aFunc, DdNode * bCube, st__table * Visited, st__table * CutNodes ); - -/**AutomaticEnd***************************************************************/ - - -/*---------------------------------------------------------------------------*/ -/* Definition of exported functions */ -/*---------------------------------------------------------------------------*/ - -/**Function******************************************************************** - - Synopsis [Performs the binary encoding of the set of function using the given vars.] - - Description [Performs a straight binary encoding of the set of functions using - the variable cubes formed from the given set of variables. ] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -DdNode * -Extra_bddEncodingBinary( - DdManager * dd, - DdNode ** pbFuncs, // pbFuncs is the array of columns to be encoded - int nFuncs, // nFuncs is the number of columns in the array - DdNode ** pbVars, // pbVars is the array of variables to use for the codes - int nVars ) // nVars is the column multiplicity, [log2(nFuncs)] -{ - int i; - DdNode * bResult; - DdNode * bCube, * bTemp, * bProd; - - assert( nVars >= Abc_Base2Log(nFuncs) ); - - bResult = b0; Cudd_Ref( bResult ); - for ( i = 0; i < nFuncs; i++ ) - { - bCube = Extra_bddBitsToCube( dd, i, nVars, pbVars, 1 ); Cudd_Ref( bCube ); - bProd = Cudd_bddAnd( dd, bCube, pbFuncs[i] ); Cudd_Ref( bProd ); - Cudd_RecursiveDeref( dd, bCube ); - - bResult = Cudd_bddOr( dd, bProd, bTemp = bResult ); Cudd_Ref( bResult ); - Cudd_RecursiveDeref( dd, bTemp ); - Cudd_RecursiveDeref( dd, bProd ); - } - - Cudd_Deref( bResult ); - return bResult; -} /* end of Extra_bddEncodingBinary */ - - -/**Function******************************************************************** - - Synopsis [Solves the column encoding problem using a sophisticated method.] - - Description [The encoding is based on the idea of deriving functions which - depend on only one variable, which corresponds to the case of non-disjoint - decompostion. It is assumed that the variables pCVars are ordered below the variables - representing the solumns, and the first variable pCVars[0] is the topmost one.] - - SideEffects [] - - SeeAlso [Extra_bddEncodingBinary] - -******************************************************************************/ - -DdNode * -Extra_bddEncodingNonStrict( - DdManager * dd, - DdNode ** pbColumns, // pbColumns is the array of columns to be encoded; - int nColumns, // nColumns is the number of columns in the array - DdNode * bVarsCol, // bVarsCol is the cube of variables on which the columns depend - DdNode ** pCVars, // pCVars is the array of variables to use for the codes - int nMulti, // nMulti is the column multiplicity, [log2(nColumns)] - int * pSimple ) // pSimple gets the number of code variables taken from the input varibles without change -{ - DdNode * bEncoded, * bResult; - int nVarsCol = Cudd_SupportSize(dd,bVarsCol); - abctime clk; - - // cannot work with more that 32-bit codes - assert( nMulti < 32 ); - - // perform the preliminary encoding using the straight binary code - bEncoded = Extra_bddEncodingBinary( dd, pbColumns, nColumns, pCVars, nMulti ); Cudd_Ref( bEncoded ); - //printf( "Node count = %d", Cudd_DagSize(bEncoded) ); - - // set the backgroup value for counting minterms - s_Terminal = b0; - // set the level of the encoding variables - s_EncodingVarsLevel = dd->invperm[pCVars[0]->index]; - - // the current number of backtracks - s_BackTracks = 0; - // the variables that are cofactored on the topmost level where everything starts (no vars) - s_Field[0][0] = b1; - // the size of the best set of "simple" encoding variables found so far - s_nVarsBest = 0; - - // set the relation to be accessible to traversal procedures - s_Encoded = bEncoded; - // the set of all vars to be accessible to traversal procedures - s_VarAll = bVarsCol; - // the column multiplicity - s_MultiStart = nMulti; - - - clk = Abc_Clock(); - // find the simplest encoding - if ( nColumns > 2 ) - EvaluateEncodings_rec( dd, bVarsCol, nVarsCol, nMulti, 1 ); -// printf( "The number of backtracks = %d\n", s_BackTracks ); -// s_EncSearchTime += Abc_Clock() - clk; - - // allocate the temporary storage for the columns - s_pbTemp = (DdNode **)ABC_ALLOC( char, nColumns * sizeof(DdNode *) ); - -// clk = Abc_Clock(); - bResult = CreateTheCodes_rec( dd, bEncoded, 0, pCVars ); Cudd_Ref( bResult ); -// s_EncComputeTime += Abc_Clock() - clk; - - // delocate the preliminarily encoded set - Cudd_RecursiveDeref( dd, bEncoded ); -// Cudd_RecursiveDeref( dd, aEncoded ); - - ABC_FREE( s_pbTemp ); - - *pSimple = s_nVarsBest; - Cudd_Deref( bResult ); - return bResult; -} - -/**Function******************************************************************** - - Synopsis [Collects the nodes under the cut and, for each node, computes the sum of paths leading to it from the root.] - - Description [The table returned contains the set of BDD nodes pointed to under the cut - and, for each node, the BDD of the sum of paths leading to this node from the root - The sums of paths in the table are referenced. CutLevel is the first DD level - considered to be under the cut.] - - SideEffects [] - - SeeAlso [Extra_bddNodePaths] - -******************************************************************************/ - st__table * Extra_bddNodePathsUnderCut( DdManager * dd, DdNode * bFunc, int CutLevel ) -{ - st__table * Visited; // temporary table to remember the visited nodes - st__table * CutNodes; // the result goes here - st__table * Result; // the result goes here - DdNode * aFunc; - - s_CutLevel = CutLevel; - - Result = st__init_table( st__ptrcmp, st__ptrhash);; - // the terminal cases - if ( Cudd_IsConstant( bFunc ) ) - { - if ( bFunc == b1 ) - { - st__insert( Result, (char*)b1, (char*)b1 ); - Cudd_Ref( b1 ); - Cudd_Ref( b1 ); - } - else - { - st__insert( Result, (char*)b0, (char*)b0 ); - Cudd_Ref( b0 ); - Cudd_Ref( b0 ); - } - return Result; - } - - // create the ADD to simplify processing (no complemented edges) - aFunc = Cudd_BddToAdd( dd, bFunc ); Cudd_Ref( aFunc ); - - // Step 1: Start the tables and collect information about the nodes above the cut - // this information tells how many edges point to each node - Visited = st__init_table( st__ptrcmp, st__ptrhash);; - CutNodes = st__init_table( st__ptrcmp, st__ptrhash);; - - CountNodeVisits_rec( dd, aFunc, Visited ); - - // Step 2: Traverse the BDD using the visited table and compute the sum of paths - CollectNodesAndComputePaths_rec( dd, aFunc, b1, Visited, CutNodes ); - - // at this point the table of cut nodes is ready and the table of visited is useless - { - st__generator * gen; - DdNode * aNode; - traventry * p; - st__foreach_item( Visited, gen, (const char**)&aNode, (char**)&p ) - { - Cudd_RecursiveDeref( dd, p->bSum ); - ABC_FREE( p ); - } - st__free_table( Visited ); - } - - // go through the table CutNodes and create the BDD and the path to be returned - { - st__generator * gen; - DdNode * aNode, * bNode, * bSum; - st__foreach_item( CutNodes, gen, (const char**)&aNode, (char**)&bSum) - { - // aNode is not referenced, because aFunc is holding it - bNode = Cudd_addBddPattern( dd, aNode ); Cudd_Ref( bNode ); - st__insert( Result, (char*)bNode, (char*)bSum ); - // the new table takes both refs - } - st__free_table( CutNodes ); - } - - // dereference the ADD - Cudd_RecursiveDeref( dd, aFunc ); - - // return the table - return Result; - -} /* end of Extra_bddNodePathsUnderCut */ - -/**Function******************************************************************** - - Synopsis [Collects the nodes under the cut in the ADD starting from the given set of ADD nodes.] - - Description [Takes the array, paNodes, of ADD nodes to start the traversal, - the array, pbCubes, of BDD cubes to start the traversal with in each node, - and the number, nNodes, of ADD nodes and BDD cubes in paNodes and pbCubes. - Returns the number of columns found. Fills in paNodesRes (pbCubesRes) - with the set of ADD columns (BDD paths). These arrays should be allocated - by the user.] - - SideEffects [] - - SeeAlso [Extra_bddNodePaths] - -******************************************************************************/ -int Extra_bddNodePathsUnderCutArray( DdManager * dd, DdNode ** paNodes, DdNode ** pbCubes, int nNodes, DdNode ** paNodesRes, DdNode ** pbCubesRes, int CutLevel ) -{ - st__table * Visited; // temporary table to remember the visited nodes - st__table * CutNodes; // the nodes under the cut go here - int i, Counter; - - s_CutLevel = CutLevel; - - // there should be some nodes - assert( nNodes > 0 ); - if ( nNodes == 1 && Cudd_IsConstant( paNodes[0] ) ) - { - if ( paNodes[0] == a1 ) - { - paNodesRes[0] = a1; Cudd_Ref( a1 ); - pbCubesRes[0] = pbCubes[0]; Cudd_Ref( pbCubes[0] ); - } - else - { - paNodesRes[0] = a0; Cudd_Ref( a0 ); - pbCubesRes[0] = pbCubes[0]; Cudd_Ref( pbCubes[0] ); - } - return 1; - } - - // Step 1: Start the table and collect information about the nodes above the cut - // this information tells how many edges point to each node - CutNodes = st__init_table( st__ptrcmp, st__ptrhash);; - Visited = st__init_table( st__ptrcmp, st__ptrhash);; - - for ( i = 0; i < nNodes; i++ ) - CountNodeVisits_rec( dd, paNodes[i], Visited ); - - // Step 2: Traverse the BDD using the visited table and compute the sum of paths - for ( i = 0; i < nNodes; i++ ) - CollectNodesAndComputePaths_rec( dd, paNodes[i], pbCubes[i], Visited, CutNodes ); - - // at this point, the table of cut nodes is ready and the table of visited is useless - { - st__generator * gen; - DdNode * aNode; - traventry * p; - st__foreach_item( Visited, gen, (const char**)&aNode, (char**)&p ) - { - Cudd_RecursiveDeref( dd, p->bSum ); - ABC_FREE( p ); - } - st__free_table( Visited ); - } - - // go through the table CutNodes and create the BDD and the path to be returned - { - st__generator * gen; - DdNode * aNode, * bSum; - Counter = 0; - st__foreach_item( CutNodes, gen, (const char**)&aNode, (char**)&bSum) - { - paNodesRes[Counter] = aNode; Cudd_Ref( aNode ); - pbCubesRes[Counter] = bSum; - Counter++; - } - st__free_table( CutNodes ); - } - - // return the number of cofactors found - return Counter; - -} /* end of Extra_bddNodePathsUnderCutArray */ - -/**Function************************************************************* - - Synopsis [Collects all the BDD nodes into the table.] - - Description [] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -void extraCollectNodes( DdNode * Func, st__table * tNodes ) -{ - DdNode * FuncR; - FuncR = Cudd_Regular(Func); - if ( st__find_or_add( tNodes, (char*)FuncR, NULL ) ) - return; - if ( cuddIsConstant(FuncR) ) - return; - extraCollectNodes( cuddE(FuncR), tNodes ); - extraCollectNodes( cuddT(FuncR), tNodes ); -} - -/**Function************************************************************* - - Synopsis [Collects all the nodes of one DD into the table.] - - Description [] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ - st__table * Extra_CollectNodes( DdNode * Func ) -{ - st__table * tNodes; - tNodes = st__init_table( st__ptrcmp, st__ptrhash ); - extraCollectNodes( Func, tNodes ); - return tNodes; -} - -/**Function************************************************************* - - Synopsis [Updates the topmost level from which the given node is referenced.] - - Description [Takes the table which maps each BDD nodes (including the constants) - into the topmost level on which this node counts as a cofactor. Takes the topmost - level, on which this node counts as a cofactor (see Extra_ProfileWidthFast(). - Takes the node, for which the table entry should be updated.] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -void extraProfileUpdateTopLevel( st__table * tNodeTopRef, int TopLevelNew, DdNode * node ) -{ - int * pTopLevel; - - if ( st__find_or_add( tNodeTopRef, (char*)node, (char***)&pTopLevel ) ) - { // the node is already referenced - // the current top level should be updated if it is larger than the new level - if ( *pTopLevel > TopLevelNew ) - *pTopLevel = TopLevelNew; - } - else - { // the node is not referenced - // its level should be set to the current new level - *pTopLevel = TopLevelNew; - } -} -/**Function************************************************************* - - Synopsis [Fast computation of the BDD profile.] - - Description [The array to store the profile is given by the user and should - contain at least as many entries as there is the maximum of the BDD/ZDD - size of the manager PLUS ONE. - When we say that the widths of the DD on level L is W, we mean the following. - Let us create the cut between the level L-1 and the level L and count the number - of different DD nodes pointed to across the cut. This number is the width W. - From this it follows the on level 0, the width is equal to the number of external - pointers to the considered DDs. If there is only one DD, then the profile on - level 0 is always 1. If this DD is rooted in the topmost variable, then the width - on level 1 is always 2, etc. The width at the level equal to dd->size is the - number of terminal nodes in the DD. (Because we consider the first level #0 - and the last level #dd->size, the profile array should contain dd->size+1 entries.) - ] - - SideEffects [This procedure will not work for BDDs w/ complement edges, only for ADDs and ZDDs] - - SeeAlso [] - -***********************************************************************/ -int Extra_ProfileWidth( DdManager * dd, DdNode * Func, int * pProfile, int CutLevel ) -{ - st__generator * gen; - st__table * tNodeTopRef; // this table stores the top level from which this node is pointed to - st__table * tNodes; - DdNode * node; - DdNode * nodeR; - int LevelStart, Limit; - int i, size; - int WidthMax; - - // start the mapping table - tNodeTopRef = st__init_table( st__ptrcmp, st__ptrhash);; - // add the topmost node to the profile - extraProfileUpdateTopLevel( tNodeTopRef, 0, Func ); - - // collect all nodes - tNodes = Extra_CollectNodes( Func ); - // go though all the nodes and set the top level the cofactors are pointed from -// Cudd_ForeachNode( dd, Func, genDD, node ) - st__foreach_item( tNodes, gen, (const char**)&node, NULL ) - { -// assert( Cudd_Regular(node) ); // this procedure works only with ADD/ZDD (not BDD w/ compl.edges) - nodeR = Cudd_Regular(node); - if ( cuddIsConstant(nodeR) ) - continue; - // this node is not a constant - consider its cofactors - extraProfileUpdateTopLevel( tNodeTopRef, dd->perm[node->index]+1, cuddE(nodeR) ); - extraProfileUpdateTopLevel( tNodeTopRef, dd->perm[node->index]+1, cuddT(nodeR) ); - } - st__free_table( tNodes ); - - // clean the profile - size = ddMax(dd->size, dd->sizeZ) + 1; - for ( i = 0; i < size; i++ ) - pProfile[i] = 0; - - // create the profile - st__foreach_item( tNodeTopRef, gen, (const char**)&node, (char**)&LevelStart ) - { - nodeR = Cudd_Regular(node); - Limit = (cuddIsConstant(nodeR))? dd->size: dd->perm[nodeR->index]; - for ( i = LevelStart; i <= Limit; i++ ) - pProfile[i]++; - } - - if ( CutLevel != -1 && CutLevel != 0 ) - size = CutLevel; - - // get the max width - WidthMax = 0; - for ( i = 0; i < size; i++ ) - if ( WidthMax < pProfile[i] ) - WidthMax = pProfile[i]; - - // deref the table - st__free_table( tNodeTopRef ); - - return WidthMax; -} /* end of Extra_ProfileWidth */ - - -/*---------------------------------------------------------------------------*/ -/* Definition of internal functions */ -/*---------------------------------------------------------------------------*/ - -/*---------------------------------------------------------------------------*/ -/* Definition of static functions */ -/*---------------------------------------------------------------------------*/ - -/**Function******************************************************************** - - Synopsis [Computes the non-strict codes when evaluation is finished.] - - Description [The information about the best code is stored in s_VarOrderBest, - which has s_nVarsBest entries.] - - SideEffects [None] - -******************************************************************************/ -DdNode * CreateTheCodes_rec( DdManager * dd, DdNode * bEncoded, int Level, DdNode ** pCVars ) -// bEncoded is the preliminarily encoded set of columns -// Level is the current level in the recursion -// pCVars are the variables to be used for encoding -{ - DdNode * bRes; - if ( Level == s_nVarsBest ) - { // the terminal case, when we need to remap the encoded function - // from the preliminary encoded variables to the new ones - st__table * CutNodes; - int nCols; -// double nMints; -/* -#ifdef _DEBUG - - { - DdNode * bTemp; - // make sure that the given number of variables is enough - bTemp = Cudd_bddExistAbstract( dd, bEncoded, s_VarAll ); Cudd_Ref( bTemp ); -// nMints = Cudd_CountMinterm( dd, bTemp, s_MultiStart ); - nMints = Extra_CountMintermsSimple( bTemp, (1<<s_MultiStart) ); - if ( nMints > Extra_Power2( s_MultiStart-Level ) ) - { // the number of minterms is too large to encode the columns - // using the given minimum number of encoding variables - assert( 0 ); - } - Cudd_RecursiveDeref( dd, bTemp ); - } -#endif -*/ - // get the columns to be re-encoded - CutNodes = Extra_bddNodePathsUnderCut( dd, bEncoded, s_EncodingVarsLevel ); - // LUT size is the cut level because because the temporary encoding variables - // are above the functional variables - this is not true!!! - // the temporary variables are below! - - // put the entries from the table into the temporary array - { - st__generator * gen; - DdNode * bColumn, * bCode; - nCols = 0; - st__foreach_item( CutNodes, gen, (const char**)&bCode, (char**)&bColumn ) - { - if ( bCode == b0 ) - { // the unused part of the columns - Cudd_RecursiveDeref( dd, bColumn ); - Cudd_RecursiveDeref( dd, bCode ); - continue; - } - else - { - s_pbTemp[ nCols ] = bColumn; // takes ref - Cudd_RecursiveDeref( dd, bCode ); - nCols++; - } - } - st__free_table( CutNodes ); -// assert( nCols == (int)nMints ); - } - - // encode the columns - if ( s_MultiStart-Level == 0 ) // we reached the bottom level of recursion - { - assert( nCols == 1 ); -// assert( (int)nMints == 1 ); - bRes = s_pbTemp[0]; Cudd_Ref( bRes ); - } - else - { - bRes = Extra_bddEncodingBinary( dd, s_pbTemp, nCols, pCVars+Level, s_MultiStart-Level ); Cudd_Ref( bRes ); - } - - // deref the columns - { - int i; - for ( i = 0; i < nCols; i++ ) - Cudd_RecursiveDeref( dd, s_pbTemp[i] ); - } - } - else - { - // cofactor the problem as specified in the best solution - DdNode * bCof0, * bCof1; - DdNode * bRes0, * bRes1; - DdNode * bProd0, * bProd1; - DdNode * bTemp; - DdNode * bVarNext = dd->vars[ s_VarOrderBest[Level] ]; - - bCof0 = Cudd_Cofactor( dd, bEncoded, Cudd_Not( bVarNext ) ); Cudd_Ref( bCof0 ); - bCof1 = Cudd_Cofactor( dd, bEncoded, bVarNext ); Cudd_Ref( bCof1 ); - - // call recursively - bRes0 = CreateTheCodes_rec( dd, bCof0, Level+1, pCVars ); Cudd_Ref( bRes0 ); - bRes1 = CreateTheCodes_rec( dd, bCof1, Level+1, pCVars ); Cudd_Ref( bRes1 ); - - Cudd_RecursiveDeref( dd, bCof0 ); - Cudd_RecursiveDeref( dd, bCof1 ); - - // compose the result using the identity (bVarNext <=> pCVars[Level]) - this is wrong! - // compose the result as follows: x'y'F0 + xyF1 - bProd0 = Cudd_bddAnd( dd, Cudd_Not(bVarNext), Cudd_Not(pCVars[Level]) ); Cudd_Ref( bProd0 ); - bProd1 = Cudd_bddAnd( dd, bVarNext , pCVars[Level] ); Cudd_Ref( bProd1 ); - - bProd0 = Cudd_bddAnd( dd, bTemp = bProd0, bRes0 ); Cudd_Ref( bProd0 ); - Cudd_RecursiveDeref( dd, bTemp ); - Cudd_RecursiveDeref( dd, bRes0 ); - - bProd1 = Cudd_bddAnd( dd, bTemp = bProd1, bRes1 ); Cudd_Ref( bProd1 ); - Cudd_RecursiveDeref( dd, bTemp ); - Cudd_RecursiveDeref( dd, bRes1 ); - - bRes = Cudd_bddOr( dd, bProd0, bProd1 ); Cudd_Ref( bRes ); - - Cudd_RecursiveDeref( dd, bProd0 ); - Cudd_RecursiveDeref( dd, bProd1 ); - } - Cudd_Deref( bRes ); - return bRes; -} - -/**Function******************************************************************** - - Synopsis [Computes the current set of variables and counts the number of minterms.] - - Description [Old implementation.] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -void EvaluateEncodings_rec( DdManager * dd, DdNode * bVarsCol, int nVarsCol, int nMulti, int Level ) -// bVarsCol is the set of remaining variables -// nVarsCol is the number of remaining variables -// nMulti is the number of encoding variables to be used -// Level is the level of recursion, from which this function is called -// if we successfully finish this procedure, Level also stands for how many encoding variabled we saved -{ - int i, k; - int nEntries = (1<<(Level-1)); // the number of entries in the field of the previous level - DdNode * bVars0, * bVars1; // the cofactors - unsigned nMint0, nMint1; // the number of minterms - DdNode * bTempV; - DdNode * bVarTop; - int fBreak; - - - // there is no need to search above this level - if ( Level > s_MaxDepth ) - return; - - // if there are no variables left, quit the research - if ( bVarsCol == b1 ) - return; - - if ( s_BackTracks > s_BackTrackLimit ) - return; - - s_BackTracks++; - - // otherwise, go through the remaining variables - for ( bTempV = bVarsCol; bTempV != b1; bTempV = cuddT(bTempV) ) - { - // the currently tested variable - bVarTop = dd->vars[bTempV->index]; - - // put it into the array - s_VarOrderCur[Level-1] = bTempV->index; - - // go through the entries and fill them out by cofactoring - fBreak = 0; - for ( i = 0; i < nEntries; i++ ) - { - bVars0 = ComputeVarSetAndCountMinterms( dd, s_Field[Level-1][i], Cudd_Not(bVarTop), &nMint0 ); - Cudd_Ref( bVars0 ); - - if ( nMint0 > Extra_Power2( nMulti-1 ) ) - { - // there is no way to encode - dereference and return - Cudd_RecursiveDeref( dd, bVars0 ); - fBreak = 1; - break; - } - - bVars1 = ComputeVarSetAndCountMinterms( dd, s_Field[Level-1][i], bVarTop, &nMint1 ); - Cudd_Ref( bVars1 ); - - if ( nMint1 > Extra_Power2( nMulti-1 ) ) - { - // there is no way to encode - dereference and return - Cudd_RecursiveDeref( dd, bVars0 ); - Cudd_RecursiveDeref( dd, bVars1 ); - fBreak = 1; - break; - } - - // otherwise, add these two cofactors - s_Field[Level][2*i + 0] = bVars0; // takes ref - s_Field[Level][2*i + 1] = bVars1; // takes ref - } - - if ( !fBreak ) - { - DdNode * bVarsRem; - // if we ended up here, it means that the cofactors w.r.t. variable bVarTop satisfy the condition - // save this situation - if ( s_nVarsBest < Level ) - { - s_nVarsBest = Level; - // copy the variable assignment - for ( k = 0; k < Level; k++ ) - s_VarOrderBest[k] = s_VarOrderCur[k]; - } - - // call recursively - // get the new variable set - if ( nMulti-1 > 0 ) - { - bVarsRem = Cudd_bddExistAbstract( dd, bVarsCol, bVarTop ); Cudd_Ref( bVarsRem ); - EvaluateEncodings_rec( dd, bVarsRem, nVarsCol-1, nMulti-1, Level+1 ); - Cudd_RecursiveDeref( dd, bVarsRem ); - } - } - - // deref the contents of the array - for ( k = 0; k < i; k++ ) - { - Cudd_RecursiveDeref( dd, s_Field[Level][2*k + 0] ); - Cudd_RecursiveDeref( dd, s_Field[Level][2*k + 1] ); - } - - // if the solution is found, there is no need to continue - if ( s_nVarsBest == s_MaxDepth ) - return; - - // if the solution is found, there is no need to continue - if ( s_nVarsBest == s_MultiStart ) - return; - } - // at this point, we have tried all possible directions in the space of variables -} - -/**Function******************************************************************** - - Synopsis [Computes the current set of variables and counts the number of minterms.] - - Description [] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -DdNode * ComputeVarSetAndCountMinterms( DdManager * dd, DdNode * bVars, DdNode * bVarTop, unsigned * Cost ) -// takes bVars - the variables cofactored so far (some of them may be in negative polarity) -// bVarTop - the topmost variable w.r.t. which to cofactor (may be in negative polarity) -// returns the cost and the new set of variables (bVars & bVarTop) -{ - DdNode * bVarsRes; - - // get the resulting set of variables - bVarsRes = Cudd_bddAnd( dd, bVars, bVarTop ); Cudd_Ref( bVarsRes ); - - // increment signature before calling Cudd_CountCofactorMinterms() - s_Signature++; - *Cost = Extra_CountCofactorMinterms( dd, s_Encoded, bVarsRes, s_VarAll ); - - Cudd_Deref( bVarsRes ); -// s_CountCalls++; - return bVarsRes; -} - -/**Function******************************************************************** - - Synopsis [Computes the current set of variables and counts the number of minterms.] - - Description [The old implementation, which is approximately 4 times slower.] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -DdNode * ComputeVarSetAndCountMinterms2( DdManager * dd, DdNode * bVars, DdNode * bVarTop, unsigned * Cost ) -{ - DdNode * bVarsRes; - DdNode * bCof, * bFun; - - bVarsRes = Cudd_bddAnd( dd, bVars, bVarTop ); Cudd_Ref( bVarsRes ); - - bCof = Cudd_Cofactor( dd, s_Encoded, bVarsRes ); Cudd_Ref( bCof ); - bFun = Cudd_bddExistAbstract( dd, bCof, s_VarAll ); Cudd_Ref( bFun ); - *Cost = (unsigned)Cudd_CountMinterm( dd, bFun, s_MultiStart ); - Cudd_RecursiveDeref( dd, bFun ); - Cudd_RecursiveDeref( dd, bCof ); - - Cudd_Deref( bVarsRes ); -// s_CountCalls++; - return bVarsRes; -} - - -/**Function******************************************************************** - - Synopsis [Counts the number of encoding minterms pointed to by the cofactor of the function.] - - Description [] - - SideEffects [None] - -******************************************************************************/ -unsigned Extra_CountCofactorMinterms( DdManager * dd, DdNode * bFunc, DdNode * bVarsCof, DdNode * bVarsAll ) -// this function computes how many minterms depending on the encoding variables -// are there in the cofactor of bFunc w.r.t. variables bVarsCof -// bFunc is assumed to depend on variables s_VarsAll -// the variables s_VarsAll should be ordered above the encoding variables -{ - unsigned HKey; - DdNode * bFuncR; - - // if the function is zero, there are no minterms -// if ( bFunc == b0 ) -// return 0; - -// if ( st__lookup(Visited, (char*)bFunc, NULL) ) -// return 0; - -// HKey = hashKey2c( s_Signature, bFuncR ); -// if ( HHTable1[HKey].Sign == s_Signature && HHTable1[HKey].Arg1 == bFuncR ) // this node is visited -// return 0; - - - // check the hash-table - bFuncR = Cudd_Regular(bFunc); -// HKey = hashKey2( s_Signature, bFuncR, _TABLESIZE_COF ); - HKey = hashKey2( s_Signature, bFunc, _TABLESIZE_COF ); - for ( ; HHTable1[HKey].Sign == s_Signature; HKey = (HKey+1) % _TABLESIZE_COF ) -// if ( HHTable1[HKey].Arg1 == bFuncR ) // this node is visited - if ( HHTable1[HKey].Arg1 == bFunc ) // this node is visited - return 0; - - - // if the function is already the code - if ( dd->perm[bFuncR->index] >= s_EncodingVarsLevel ) - { -// st__insert(Visited, (char*)bFunc, NULL); - -// HHTable1[HKey].Sign = s_Signature; -// HHTable1[HKey].Arg1 = bFuncR; - - assert( HHTable1[HKey].Sign != s_Signature ); - HHTable1[HKey].Sign = s_Signature; -// HHTable1[HKey].Arg1 = bFuncR; - HHTable1[HKey].Arg1 = bFunc; - - return Extra_CountMintermsSimple( bFunc, (1<<s_MultiStart) ); - } - else - { - DdNode * bFunc0, * bFunc1; - DdNode * bVarsCof0, * bVarsCof1; - DdNode * bVarsCofR = Cudd_Regular(bVarsCof); - unsigned Res; - - // get the levels - int LevelF = dd->perm[bFuncR->index]; - int LevelC = cuddI(dd,bVarsCofR->index); - int LevelA = dd->perm[bVarsAll->index]; - - int LevelTop = LevelF; - - if ( LevelTop > LevelC ) - LevelTop = LevelC; - - if ( LevelTop > LevelA ) - LevelTop = LevelA; - - // the top var in the function or in cofactoring vars always belongs to the set of all vars - assert( !( LevelTop == LevelF || LevelTop == LevelC ) || LevelTop == LevelA ); - - // cofactor the function - if ( LevelTop == LevelF ) - { - if ( bFuncR != bFunc ) // bFunc is complemented - { - bFunc0 = Cudd_Not( cuddE(bFuncR) ); - bFunc1 = Cudd_Not( cuddT(bFuncR) ); - } - else - { - bFunc0 = cuddE(bFuncR); - bFunc1 = cuddT(bFuncR); - } - } - else // bVars is higher in the variable order - bFunc0 = bFunc1 = bFunc; - - // cofactor the cube - if ( LevelTop == LevelC ) - { - if ( bVarsCofR != bVarsCof ) // bFunc is complemented - { - bVarsCof0 = Cudd_Not( cuddE(bVarsCofR) ); - bVarsCof1 = Cudd_Not( cuddT(bVarsCofR) ); - } - else - { - bVarsCof0 = cuddE(bVarsCofR); - bVarsCof1 = cuddT(bVarsCofR); - } - } - else // bVars is higher in the variable order - bVarsCof0 = bVarsCof1 = bVarsCof; - - // there are two cases: - // (1) the top variable belongs to the cofactoring variables - // (2) the top variable does not belong to the cofactoring variables - - // (1) the top variable belongs to the cofactoring variables - Res = 0; - if ( LevelTop == LevelC ) - { - if ( bVarsCof1 == b0 ) // this is a negative cofactor - { - if ( bFunc0 != b0 ) - Res = Extra_CountCofactorMinterms( dd, bFunc0, bVarsCof0, cuddT(bVarsAll) ); - } - else // this is a positive cofactor - { - if ( bFunc1 != b0 ) - Res = Extra_CountCofactorMinterms( dd, bFunc1, bVarsCof1, cuddT(bVarsAll) ); - } - } - else - { - if ( bFunc0 != b0 ) - Res += Extra_CountCofactorMinterms( dd, bFunc0, bVarsCof0, cuddT(bVarsAll) ); - - if ( bFunc1 != b0 ) - Res += Extra_CountCofactorMinterms( dd, bFunc1, bVarsCof1, cuddT(bVarsAll) ); - } - -// st__insert(Visited, (char*)bFunc, NULL); - -// HHTable1[HKey].Sign = s_Signature; -// HHTable1[HKey].Arg1 = bFuncR; - - // skip through the entries with the same signatures - // (these might have been created at the time of recursive calls) - for ( ; HHTable1[HKey].Sign == s_Signature; HKey = (HKey+1) % _TABLESIZE_COF ); - assert( HHTable1[HKey].Sign != s_Signature ); - HHTable1[HKey].Sign = s_Signature; -// HHTable1[HKey].Arg1 = bFuncR; - HHTable1[HKey].Arg1 = bFunc; - - return Res; - } -} - -/**Function******************************************************************** - - Synopsis [Counts the number of minterms.] - - Description [This function counts minterms for functions up to 32 variables - using a local cache. The terminal value (s_Termina) should be adjusted for - BDDs and ADDs.] - - SideEffects [None] - -******************************************************************************/ -unsigned Extra_CountMintermsSimple( DdNode * bFunc, unsigned max ) -{ - unsigned HKey; - - // normalize - if ( Cudd_IsComplement(bFunc) ) - return max - Extra_CountMintermsSimple( Cudd_Not(bFunc), max ); - - // now it is known that the function is not complemented - if ( cuddIsConstant(bFunc) ) - return ((bFunc==s_Terminal)? 0: max); - - // check cache - HKey = hashKey2( bFunc, max, _TABLESIZE_MINT ); - if ( HHTable2[HKey].Arg1 == bFunc && HHTable2[HKey].Arg2 == max ) - return HHTable2[HKey].Res; - else - { - // min = min0/2 + min1/2; - unsigned min = (Extra_CountMintermsSimple( cuddE(bFunc), max ) >> 1) + - (Extra_CountMintermsSimple( cuddT(bFunc), max ) >> 1); - - HHTable2[HKey].Arg1 = bFunc; - HHTable2[HKey].Arg2 = max; - HHTable2[HKey].Res = min; - - return min; - } -} /* end of Extra_CountMintermsSimple */ - - -/**Function******************************************************************** - - Synopsis [Visits the nodes.] - - Description [Visits the nodes above the cut and the nodes pointed to below the cut; - collects the visited nodes, counts how many times each node is visited, and sets - the path-sum to be the constant zero BDD.] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -void CountNodeVisits_rec( DdManager * dd, DdNode * aFunc, st__table * Visited ) - -{ - traventry * p; - char **slot; - if ( st__find_or_add(Visited, (char*)aFunc, &slot) ) - { // the entry already exists - p = (traventry*) *slot; - // increment the counter of incoming edges - p->nEdges++; - return; - } - // this node has not been visited - assert( !Cudd_IsComplement(aFunc) ); - - // create the new traversal entry - p = (traventry *) ABC_ALLOC( char, sizeof(traventry) ); - // set the initial sum of edges to zero BDD - p->bSum = b0; Cudd_Ref( b0 ); - // set the starting number of incoming edges - p->nEdges = 1; - // set this entry into the slot - *slot = (char*)p; - - // recur if the node is above the cut - if ( cuddI(dd,aFunc->index) < s_CutLevel ) - { - CountNodeVisits_rec( dd, cuddE(aFunc), Visited ); - CountNodeVisits_rec( dd, cuddT(aFunc), Visited ); - } -} /* end of CountNodeVisits_rec */ - - -/**Function******************************************************************** - - Synopsis [Revisits the nodes and computes the paths.] - - Description [This function visits the nodes above the cut having the goal of - summing all the incomming BDD edges; when this function comes across the node - below the cut, it saves this node in the CutNode table.] - - SideEffects [] - - SeeAlso [] - -******************************************************************************/ -void CollectNodesAndComputePaths_rec( DdManager * dd, DdNode * aFunc, DdNode * bCube, st__table * Visited, st__table * CutNodes ) -{ - // find the node in the visited table - DdNode * bTemp; - traventry * p; - char **slot; - if ( st__find_or_add(Visited, (char*)aFunc, &slot) ) - { // the node is found - // get the pointer to the traversal entry - p = (traventry*) *slot; - - // make sure that the counter of incoming edges is positive - assert( p->nEdges > 0 ); - - // add the cube to the currently accumulated cubes - p->bSum = Cudd_bddOr( dd, bTemp = p->bSum, bCube ); Cudd_Ref( p->bSum ); - Cudd_RecursiveDeref( dd, bTemp ); - - // decrement the number of visits - p->nEdges--; - - // if more visits to this node are expected, return - if ( p->nEdges ) - return; - else // if ( p->nEdges == 0 ) - { // this is the last visit - propagate the cube - - // check where this node is - if ( cuddI(dd,aFunc->index) < s_CutLevel ) - { // the node is above the cut - DdNode * bCube0, * bCube1; - - // get the top-most variable - DdNode * bVarTop = dd->vars[aFunc->index]; - - // compute the propagated cubes - bCube0 = Cudd_bddAnd( dd, p->bSum, Cudd_Not( bVarTop ) ); Cudd_Ref( bCube0 ); - bCube1 = Cudd_bddAnd( dd, p->bSum, bVarTop ); Cudd_Ref( bCube1 ); - - // call recursively - CollectNodesAndComputePaths_rec( dd, cuddE(aFunc), bCube0, Visited, CutNodes ); - CollectNodesAndComputePaths_rec( dd, cuddT(aFunc), bCube1, Visited, CutNodes ); - - // dereference the cubes - Cudd_RecursiveDeref( dd, bCube0 ); - Cudd_RecursiveDeref( dd, bCube1 ); - return; - } - else - { // the node is below the cut - // add this node to the cut node table, if it is not yet there - -// DdNode * bNode; -// bNode = Cudd_addBddPattern( dd, aFunc ); Cudd_Ref( bNode ); - if ( st__find_or_add(CutNodes, (char*)aFunc, &slot) ) - { // the node exists - should never happen - assert( 0 ); - } - *slot = (char*) p->bSum; Cudd_Ref( p->bSum ); - // the table takes the reference of bNode - return; - } - } - } - - // the node does not exist in the visited table - should never happen - assert(0); - -} /* end of CollectNodesAndComputePaths_rec */ - - - -//////////////////////////////////////////////////////////////////////// -/// END OF FILE /// -//////////////////////////////////////////////////////////////////////// -ABC_NAMESPACE_IMPL_END - |