The core of all methods is the reordering procedure cuddSwapInPlace() which swaps two adjacent variables and is based on Rudell's paper. Returns 1 in case of success; 0 otherwise. In the case of symmetric sifting (with and without convergence) returns 1 plus the number of symmetric variables, in case of success.] SideEffects [Changes the variable order for all diagrams and clears the cache.] ******************************************************************************/ int Cudd_ReduceHeap( DdManager * table /* DD manager */, Cudd_ReorderingType heuristic /* method used for reordering */, int minsize /* bound below which no reordering occurs */) { DdHook *hook; int result; unsigned int nextDyn; #ifdef DD_STATS unsigned int initialSize; unsigned int finalSize; #endif long localTime; /* Don't reorder if there are too many dead nodes. */ if (table->keys - table->dead < (unsigned) minsize) return(1); if (heuristic == CUDD_REORDER_SAME) { heuristic = table->autoMethod; } if (heuristic == CUDD_REORDER_NONE) { return(1); } /* This call to Cudd_ReduceHeap does initiate reordering. Therefore ** we count it. */ table->reorderings++; localTime = util_cpu_time(); /* Run the hook functions. */ hook = table->preReorderingHook; while (hook != NULL) { int res = (hook->f)(table, "BDD", (void *)heuristic); if (res == 0) return(0); hook = hook->next; } if (!ddReorderPreprocess(table)) return(0); ddTotalNumberSwapping = 0; if (table->keys > table->peakLiveNodes) { table->peakLiveNodes = table->keys; } #ifdef DD_STATS initialSize = table->keys - table->isolated; ddTotalNISwaps = 0; switch(heuristic) { case CUDD_REORDER_RANDOM: case CUDD_REORDER_RANDOM_PIVOT: (void) fprintf(table->out,"#:I_RANDOM "); break; case CUDD_REORDER_SIFT: case CUDD_REORDER_SIFT_CONVERGE: case CUDD_REORDER_SYMM_SIFT: case CUDD_REORDER_SYMM_SIFT_CONV: case CUDD_REORDER_GROUP_SIFT: case CUDD_REORDER_GROUP_SIFT_CONV: (void) fprintf(table->out,"#:I_SIFTING "); break; case CUDD_REORDER_WINDOW2: case CUDD_REORDER_WINDOW3: case CUDD_REORDER_WINDOW4: case CUDD_REORDER_WINDOW2_CONV: case CUDD_REORDER_WINDOW3_CONV: case CUDD_REORDER_WINDOW4_CONV: (void) fprintf(table->out,"#:I_WINDOW "); break; case CUDD_REORDER_ANNEALING: (void) fprintf(table->out,"#:I_ANNEAL "); break; case CUDD_REORDER_GENETIC: (void) fprintf(table->out,"#:I_GENETIC "); break; case CUDD_REORDER_LINEAR: case CUDD_REORDER_LINEAR_CONVERGE: (void) fprintf(table->out,"#:I_LINSIFT "); break; case CUDD_REORDER_EXACT: (void) fprintf(table->out,"#:I_EXACT "); break; default: return(0); } (void) fprintf(table->out,"%8d: initial size",initialSize); #endif /* See if we should use alternate threshold for maximum growth. */ if (table->reordCycle && table->reorderings % table->reordCycle == 0) { double saveGrowth = table->maxGrowth; table->maxGrowth = table->maxGrowthAlt; result = cuddTreeSifting(table,heuristic); table->maxGrowth = saveGrowth; } else { result = cuddTreeSifting(table,heuristic); } #ifdef DD_STATS (void) fprintf(table->out,"\n"); finalSize = table->keys - table->isolated; (void) fprintf(table->out,"#:F_REORDER %8d: final size\n",finalSize); (void) fprintf(table->out,"#:T_REORDER %8g: total time (sec)\n", ((double)(util_cpu_time() - localTime)/1000.0)); (void) fprintf(table->out,"#:N_REORDER %8d: total swaps\n", ddTotalNumberSwapping); (void) fprintf(table->out,"#:M_REORDER %8d: NI swaps\n",ddTotalNISwaps); #endif if (result == 0) return(0); if (!ddReorderPostprocess(table)) return(0); if (table->realign) { if (!cuddZddAlignToBdd(table)) return(0); } nextDyn = (table->keys - table->constants.keys + 1) * DD_DYN_RATIO + table->constants.keys; if (table->reorderings < 20 || nextDyn > table->nextDyn) table->nextDyn = nextDyn; else table->nextDyn += 20; table->reordered = 1; /* Run hook functions. */ hook = table->postReorderingHook; while (hook != NULL) { int res = (hook->f)(table, "BDD", (void *)localTime); if (res == 0) return(0); hook = hook->next; } /* Update cumulative reordering time. */ table->reordTime += util_cpu_time() - localTime; return(result); } /* end of Cudd_ReduceHeap */ /**Function******************************************************************** Synopsis [Reorders variables according to given permutation.] Description [Reorders variables according to given permutation. The i-th entry of the permutation array contains the index of the variable that should be brought to the i-th level. The size of the array should be equal or greater to the number of variables currently in use. Returns 1 in case of success; 0 otherwise.] SideEffects [Changes the variable order for all diagrams and clears the cache.] SeeAlso [Cudd_ReduceHeap] ******************************************************************************/ int Cudd_ShuffleHeap( DdManager * table /* DD manager */, int * permutation /* required variable permutation */) { int result; int i; int identity = 1; int *perm; /* Don't waste time in case of identity permutation. */ for (i = 0; i < table->size; i++) { if (permutation[i] != table->invperm[i]) { identity = 0; break; } } if (identity == 1) { return(1); } if (!ddReorderPreprocess(table)) return(0); if (table->keys > table->peakLiveNodes) { table->peakLiveNodes = table->keys; } perm = ABC_ALLOC(int, table->size); for (i = 0; i < table->size; i++) perm[permutation[i]] = i; if (!ddCheckPermuation(table,table->tree,perm,permutation)) { ABC_FREE(perm); return(0); } if (!ddUpdateMtrTree(table,table->tree,perm,permutation)) { ABC_FREE(perm); return(0); } ABC_FREE(perm); result = ddShuffle(table,permutation); if (!ddReorderPostprocess(table)) return(0); return(result); } /* end of Cudd_ShuffleHeap */ /*---------------------------------------------------------------------------*/ /* Definition of internal functions */ /*---------------------------------------------------------------------------*/ /**Function******************************************************************** Synopsis [Dynamically allocates a Node.] Description [Dynamically allocates a Node. This procedure is similar to cuddAllocNode in Cudd_Table.c, but it does not attempt garbage collection, because during reordering there are no dead nodes. Returns a pointer to a new node if successful; NULL is memory is full.] SideEffects [None] SeeAlso [cuddAllocNode] ******************************************************************************/ DdNode * cuddDynamicAllocNode( DdManager * table) { int i; DdNodePtr *mem; DdNode *list, *node; extern DD_OOMFP MMoutOfMemory; DD_OOMFP saveHandler; if (table->nextFree == NULL) { /* free list is empty */ /* Try to allocate a new block. */ saveHandler = MMoutOfMemory; MMoutOfMemory = Cudd_OutOfMem; // mem = (DdNodePtr *) ABC_ALLOC(DdNode, DD_MEM_CHUNK + 1); mem = (DdNodePtr *) ABC_ALLOC(DdNode, DD_MEM_CHUNK + 2); MMoutOfMemory = saveHandler; if (mem == NULL && table->stash != NULL) { ABC_FREE(table->stash); table->stash = NULL; /* Inhibit resizing of tables. */ table->maxCacheHard = table->cacheSlots - 1; table->cacheSlack = - (int) (table->cacheSlots + 1); for (i = 0; i < table->size; i++) { table->subtables[i].maxKeys <<= 2; } // mem = (DdNodePtr *) ABC_ALLOC(DdNode,DD_MEM_CHUNK + 1); mem = (DdNodePtr *) ABC_ALLOC(DdNode,DD_MEM_CHUNK + 2); } if (mem == NULL) { /* Out of luck. Call the default handler to do ** whatever it specifies for a failed malloc. If this ** handler returns, then set error code, print ** warning, and return. */ (*MMoutOfMemory)(sizeof(DdNode)*(DD_MEM_CHUNK + 1)); table->errorCode = CUDD_MEMORY_OUT; #ifdef DD_VERBOSE (void) fprintf(table->err, "cuddDynamicAllocNode: out of memory"); (void) fprintf(table->err,"Memory in use = %lu\n", table->memused); #endif return(NULL); } else { /* successful allocation; slice memory */ unsigned long offset; table->memused += (DD_MEM_CHUNK + 1) * sizeof(DdNode); mem[0] = (DdNode *) table->memoryList; table->memoryList = mem; /* Here we rely on the fact that the size of a DdNode is a ** power of 2 and a multiple of the size of a pointer. ** If we align one node, all the others will be aligned ** as well. */ // offset = (unsigned long) mem & (sizeof(DdNode) - 1); // mem += (sizeof(DdNode) - offset) / sizeof(DdNodePtr); offset = (unsigned long) mem & (32 - 1); mem += (32 - offset) / sizeof(DdNodePtr); #ifdef DD_DEBUG // assert(((unsigned long) mem & (sizeof(DdNode) - 1)) == 0); assert(((unsigned long) mem & (32 - 1)) == 0); #endif list = (DdNode *) mem; i = 1; do { list[i - 1].ref = 0; list[i - 1].next = &list[i]; } while (++i < DD_MEM_CHUNK); list[DD_MEM_CHUNK-1].ref = 0; list[DD_MEM_CHUNK - 1].next = NULL; table->nextFree = &list[0]; } } /* if free list empty */ node = table->nextFree; table->nextFree = node->next; //node->Id = 0; return (node); } /* end of cuddDynamicAllocNode */ /**Function******************************************************************** Synopsis [Implementation of Rudell's sifting algorithm.] Description [Implementation of Rudell's sifting algorithm. Assumes that no dead nodes are present.
M be the ratio of the two numbers. cuddBddAlignToZdd
then considers the ZDD variables from M*i to
(M+1)*i-1 as corresponding to BDD variable
i. This function should be normally called from
Cudd_zddReduceHeap, which clears the cache. Returns 1 in case of
success; 0 otherwise.]
SideEffects [Changes the BDD variable order for all diagrams and performs
garbage collection of the BDD unique table.]
SeeAlso [Cudd_ShuffleHeap Cudd_zddReduceHeap]
******************************************************************************/
int
cuddBddAlignToZdd(
DdManager * table /* DD manager */)
{
int *invperm; /* permutation array */
int M; /* ratio of ZDD variables to BDD variables */
int i; /* loop index */
int result; /* return value */
/* We assume that a ratio of 0 is OK. */
if (table->size == 0)
return(1);
M = table->sizeZ / table->size;
/* Check whether the number of ZDD variables is a multiple of the
** number of BDD variables.
*/
if (M * table->size != table->sizeZ)
return(0);
/* Create and initialize the inverse permutation array. */
invperm = ABC_ALLOC(int,table->size);
if (invperm == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
return(0);
}
for (i = 0; i < table->sizeZ; i += M) {
int indexZ = table->invpermZ[i];
int index = indexZ / M;
invperm[i / M] = index;
}
/* Eliminate dead nodes. Do not scan the cache again, because we
** assume that Cudd_zddReduceHeap has already cleared it.
*/
cuddGarbageCollect(table,0);
/* Initialize number of isolated projection functions. */
table->isolated = 0;
for (i = 0; i < table->size; i++) {
if (table->vars[i]->ref == 1) table->isolated++;
}
/* Initialize the interaction matrix. */
result = cuddInitInteract(table);
if (result == 0) return(0);
result = ddShuffle(table, invperm);
ABC_FREE(invperm);
/* Free interaction matrix. */
ABC_FREE(table->interact);
/* Fix the BDD variable group tree. */
bddFixTree(table,table->tree);
return(result);
} /* end of cuddBddAlignToZdd */
/*---------------------------------------------------------------------------*/
/* Definition of static functions */
/*---------------------------------------------------------------------------*/
/**Function********************************************************************
Synopsis [Comparison function used by qsort.]
Description [Comparison function used by qsort to order the
variables according to the number of keys in the subtables.
Returns the difference in number of keys between the two
variables being compared.]
SideEffects [None]
******************************************************************************/
static int
ddUniqueCompare(
int * ptrX,
int * ptrY)
{
#if 0
if (entry[*ptrY] == entry[*ptrX]) {
return((*ptrX) - (*ptrY));
}
#endif
return(entry[*ptrY] - entry[*ptrX]);
} /* end of ddUniqueCompare */
/**Function********************************************************************
Synopsis [Swaps any two variables.]
Description [Swaps any two variables. Returns the set of moves.]
SideEffects [None]
******************************************************************************/
static Move *
ddSwapAny(
DdManager * table,
int x,
int y)
{
Move *move, *moves;
int xRef,yRef;
int xNext,yNext;
int size;
int limitSize;
int tmp;
if (x >y) {
tmp = x; x = y; y = tmp;
}
xRef = x; yRef = y;
xNext = cuddNextHigh(table,x);
yNext = cuddNextLow(table,y);
moves = NULL;
limitSize = table->keys - table->isolated;
for (;;) {
if ( xNext == yNext) {
size = cuddSwapInPlace(table,x,xNext);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = x;
move->y = xNext;
move->size = size;
move->next = moves;
moves = move;
size = cuddSwapInPlace(table,yNext,y);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = yNext;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
size = cuddSwapInPlace(table,x,xNext);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = x;
move->y = xNext;
move->size = size;
move->next = moves;
moves = move;
tmp = x; x = y; y = tmp;
} else if (x == yNext) {
size = cuddSwapInPlace(table,x,xNext);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = x;
move->y = xNext;
move->size = size;
move->next = moves;
moves = move;
tmp = x; x = y; y = tmp;
} else {
size = cuddSwapInPlace(table,x,xNext);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = x;
move->y = xNext;
move->size = size;
move->next = moves;
moves = move;
size = cuddSwapInPlace(table,yNext,y);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = yNext;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
x = xNext;
y = yNext;
}
xNext = cuddNextHigh(table,x);
yNext = cuddNextLow(table,y);
if (xNext > yRef) break;
if ((double) size > table->maxGrowth * (double) limitSize) break;
if (size < limitSize) limitSize = size;
}
if (yNext>=xRef) {
size = cuddSwapInPlace(table,yNext,y);
if (size == 0) goto ddSwapAnyOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSwapAnyOutOfMem;
move->x = yNext;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
}
return(moves);
ddSwapAnyOutOfMem:
while (moves != NULL) {
move = moves->next;
cuddDeallocMove(table, moves);
moves = move;
}
return(NULL);
} /* end of ddSwapAny */
/**Function********************************************************************
Synopsis [Given xLow <= x <= xHigh moves x up and down between the
boundaries.]
Description [Given xLow <= x <= xHigh moves x up and down between the
boundaries. Finds the best position and does the required changes.
Returns 1 if successful; 0 otherwise.]
SideEffects [None]
******************************************************************************/
static int
ddSiftingAux(
DdManager * table,
int x,
int xLow,
int xHigh)
{
Move *move;
Move *moveUp; /* list of up moves */
Move *moveDown; /* list of down moves */
int initialSize;
int result;
initialSize = table->keys - table->isolated;
moveDown = NULL;
moveUp = NULL;
if (x == xLow) {
moveDown = ddSiftingDown(table,x,xHigh);
/* At this point x --> xHigh unless bounding occurred. */
if (moveDown == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
/* Move backward and stop at best position. */
result = ddSiftingBackward(table,initialSize,moveDown);
if (!result) goto ddSiftingAuxOutOfMem;
} else if (x == xHigh) {
moveUp = ddSiftingUp(table,x,xLow);
/* At this point x --> xLow unless bounding occurred. */
if (moveUp == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
/* Move backward and stop at best position. */
result = ddSiftingBackward(table,initialSize,moveUp);
if (!result) goto ddSiftingAuxOutOfMem;
} else if ((x - xLow) > (xHigh - x)) { /* must go down first: shorter */
moveDown = ddSiftingDown(table,x,xHigh);
/* At this point x --> xHigh unless bounding occurred. */
if (moveDown == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
if (moveDown != NULL) {
x = moveDown->y;
}
moveUp = ddSiftingUp(table,x,xLow);
if (moveUp == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
/* Move backward and stop at best position */
result = ddSiftingBackward(table,initialSize,moveUp);
if (!result) goto ddSiftingAuxOutOfMem;
} else { /* must go up first: shorter */
moveUp = ddSiftingUp(table,x,xLow);
/* At this point x --> xLow unless bounding occurred. */
if (moveUp == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
if (moveUp != NULL) {
x = moveUp->x;
}
moveDown = ddSiftingDown(table,x,xHigh);
if (moveDown == (Move *) CUDD_OUT_OF_MEM) goto ddSiftingAuxOutOfMem;
/* Move backward and stop at best position. */
result = ddSiftingBackward(table,initialSize,moveDown);
if (!result) goto ddSiftingAuxOutOfMem;
}
while (moveDown != NULL) {
move = moveDown->next;
cuddDeallocMove(table, moveDown);
moveDown = move;
}
while (moveUp != NULL) {
move = moveUp->next;
cuddDeallocMove(table, moveUp);
moveUp = move;
}
return(1);
ddSiftingAuxOutOfMem:
if (moveDown != (Move *) CUDD_OUT_OF_MEM) {
while (moveDown != NULL) {
move = moveDown->next;
cuddDeallocMove(table, moveDown);
moveDown = move;
}
}
if (moveUp != (Move *) CUDD_OUT_OF_MEM) {
while (moveUp != NULL) {
move = moveUp->next;
cuddDeallocMove(table, moveUp);
moveUp = move;
}
}
return(0);
} /* end of ddSiftingAux */
/**Function********************************************************************
Synopsis [Sifts a variable up.]
Description [Sifts a variable up. Moves y up until either it reaches
the bound (xLow) or the size of the DD heap increases too much.
Returns the set of moves in case of success; NULL if memory is full.]
SideEffects [None]
******************************************************************************/
static Move *
ddSiftingUp(
DdManager * table,
int y,
int xLow)
{
Move *moves;
Move *move;
int x;
int size;
int limitSize;
int xindex, yindex;
int isolated;
int L; /* lower bound on DD size */
#ifdef DD_DEBUG
int checkL;
int z;
int zindex;
#endif
moves = NULL;
yindex = table->invperm[y];
/* Initialize the lower bound.
** The part of the DD below y will not change.
** The part of the DD above y that does not interact with y will not
** change. The rest may vanish in the best case, except for
** the nodes at level xLow, which will not vanish, regardless.
*/
limitSize = L = table->keys - table->isolated;
for (x = xLow + 1; x < y; x++) {
xindex = table->invperm[x];
if (cuddTestInteract(table,xindex,yindex)) {
isolated = table->vars[xindex]->ref == 1;
L -= table->subtables[x].keys - isolated;
}
}
isolated = table->vars[yindex]->ref == 1;
L -= table->subtables[y].keys - isolated;
x = cuddNextLow(table,y);
while (x >= xLow && L <= limitSize) {
xindex = table->invperm[x];
#ifdef DD_DEBUG
checkL = table->keys - table->isolated;
for (z = xLow + 1; z < y; z++) {
zindex = table->invperm[z];
if (cuddTestInteract(table,zindex,yindex)) {
isolated = table->vars[zindex]->ref == 1;
checkL -= table->subtables[z].keys - isolated;
}
}
isolated = table->vars[yindex]->ref == 1;
checkL -= table->subtables[y].keys - isolated;
assert(L == checkL);
#endif
size = cuddSwapInPlace(table,x,y);
if (size == 0) goto ddSiftingUpOutOfMem;
/* Update the lower bound. */
if (cuddTestInteract(table,xindex,yindex)) {
isolated = table->vars[xindex]->ref == 1;
L += table->subtables[y].keys - isolated;
}
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSiftingUpOutOfMem;
move->x = x;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
if ((double) size > (double) limitSize * table->maxGrowth) break;
if (size < limitSize) limitSize = size;
y = x;
x = cuddNextLow(table,y);
}
return(moves);
ddSiftingUpOutOfMem:
while (moves != NULL) {
move = moves->next;
cuddDeallocMove(table, moves);
moves = move;
}
return((Move *) CUDD_OUT_OF_MEM);
} /* end of ddSiftingUp */
/**Function********************************************************************
Synopsis [Sifts a variable down.]
Description [Sifts a variable down. Moves x down until either it
reaches the bound (xHigh) or the size of the DD heap increases too
much. Returns the set of moves in case of success; NULL if memory is
full.]
SideEffects [None]
******************************************************************************/
static Move *
ddSiftingDown(
DdManager * table,
int x,
int xHigh)
{
Move *moves;
Move *move;
int y;
int size;
int R; /* upper bound on node decrease */
int limitSize;
int xindex, yindex;
int isolated;
#ifdef DD_DEBUG
int checkR;
int z;
int zindex;
#endif
moves = NULL;
/* Initialize R */
xindex = table->invperm[x];
limitSize = size = table->keys - table->isolated;
R = 0;
for (y = xHigh; y > x; y--) {
yindex = table->invperm[y];
if (cuddTestInteract(table,xindex,yindex)) {
isolated = table->vars[yindex]->ref == 1;
R += table->subtables[y].keys - isolated;
}
}
y = cuddNextHigh(table,x);
while (y <= xHigh && size - R < limitSize) {
#ifdef DD_DEBUG
checkR = 0;
for (z = xHigh; z > x; z--) {
zindex = table->invperm[z];
if (cuddTestInteract(table,xindex,zindex)) {
isolated = table->vars[zindex]->ref == 1;
checkR += table->subtables[z].keys - isolated;
}
}
assert(R == checkR);
#endif
/* Update upper bound on node decrease. */
yindex = table->invperm[y];
if (cuddTestInteract(table,xindex,yindex)) {
isolated = table->vars[yindex]->ref == 1;
R -= table->subtables[y].keys - isolated;
}
size = cuddSwapInPlace(table,x,y);
if (size == 0) goto ddSiftingDownOutOfMem;
move = (Move *) cuddDynamicAllocNode(table);
if (move == NULL) goto ddSiftingDownOutOfMem;
move->x = x;
move->y = y;
move->size = size;
move->next = moves;
moves = move;
if ((double) size > (double) limitSize * table->maxGrowth) break;
if (size < limitSize) limitSize = size;
x = y;
y = cuddNextHigh(table,x);
}
return(moves);
ddSiftingDownOutOfMem:
while (moves != NULL) {
move = moves->next;
cuddDeallocMove(table, moves);
moves = move;
}
return((Move *) CUDD_OUT_OF_MEM);
} /* end of ddSiftingDown */
/**Function********************************************************************
Synopsis [Given a set of moves, returns the DD heap to the position
giving the minimum size.]
Description [Given a set of moves, returns the DD heap to the
position giving the minimum size. In case of ties, returns to the
closest position giving the minimum size. Returns 1 in case of
success; 0 otherwise.]
SideEffects [None]
******************************************************************************/
static int
ddSiftingBackward(
DdManager * table,
int size,
Move * moves)
{
Move *move;
int res;
for (move = moves; move != NULL; move = move->next) {
if (move->size < size) {
size = move->size;
}
}
for (move = moves; move != NULL; move = move->next) {
if (move->size == size) return(1);
res = cuddSwapInPlace(table,(int)move->x,(int)move->y);
if (!res) return(0);
}
return(1);
} /* end of ddSiftingBackward */
/**Function********************************************************************
Synopsis [Prepares the DD heap for dynamic reordering.]
Description [Prepares the DD heap for dynamic reordering. Does
garbage collection, to guarantee that there are no dead nodes;
clears the cache, which is invalidated by dynamic reordering; initializes
the number of isolated projection functions; and initializes the
interaction matrix. Returns 1 in case of success; 0 otherwise.]
SideEffects [None]
******************************************************************************/
static int
ddReorderPreprocess(
DdManager * table)
{
int i;
int res;
/* Clear the cache. */
cuddCacheFlush(table);
cuddLocalCacheClearAll(table);
/* Eliminate dead nodes. Do not scan the cache again. */
cuddGarbageCollect(table,0);
/* Initialize number of isolated projection functions. */
table->isolated = 0;
for (i = 0; i < table->size; i++) {
if (table->vars[i]->ref == 1) table->isolated++;
}
/* Initialize the interaction matrix. */
res = cuddInitInteract(table);
if (res == 0) return(0);
return(1);
} /* end of ddReorderPreprocess */
/**Function********************************************************************
Synopsis [Cleans up at the end of reordering.]
Description []
SideEffects [None]
******************************************************************************/
static int
ddReorderPostprocess(
DdManager * table)
{
#ifdef DD_VERBOSE
(void) fflush(table->out);
#endif
/* Free interaction matrix. */
ABC_FREE(table->interact);
return(1);
} /* end of ddReorderPostprocess */
/**Function********************************************************************
Synopsis [Reorders variables according to a given permutation.]
Description [Reorders variables according to a given permutation.
The i-th permutation array contains the index of the variable that
should be brought to the i-th level. ddShuffle assumes that no
dead nodes are present and that the interaction matrix is properly
initialized. The reordering is achieved by a series of upward sifts.
Returns 1 if successful; 0 otherwise.]
SideEffects [None]
SeeAlso []
******************************************************************************/
static int
ddShuffle(
DdManager * table,
int * permutation)
{
int index;
int level;
int position;
int numvars;
int result;
#ifdef DD_STATS
long localTime;
int initialSize;
int finalSize;
int previousSize;
#endif
ddTotalNumberSwapping = 0;
#ifdef DD_STATS
localTime = util_cpu_time();
initialSize = table->keys - table->isolated;
(void) fprintf(table->out,"#:I_SHUFFLE %8d: initial size\n",
initialSize);
ddTotalNISwaps = 0;
#endif
numvars = table->size;
for (level = 0; level < numvars; level++) {
index = permutation[level];
position = table->perm[index];
#ifdef DD_STATS
previousSize = table->keys - table->isolated;
#endif
result = ddSiftUp(table,position,level);
if (!result) return(0);
#ifdef DD_STATS
if (table->keys < (unsigned) previousSize + table->isolated) {
(void) fprintf(table->out,"-");
} else if (table->keys > (unsigned) previousSize + table->isolated) {
(void) fprintf(table->out,"+"); /* should never happen */
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
#ifdef DD_STATS
(void) fprintf(table->out,"\n");
finalSize = table->keys - table->isolated;
(void) fprintf(table->out,"#:F_SHUFFLE %8d: final size\n",finalSize);
(void) fprintf(table->out,"#:T_SHUFFLE %8g: total time (sec)\n",
((double)(util_cpu_time() - localTime)/1000.0));
(void) fprintf(table->out,"#:N_SHUFFLE %8d: total swaps\n",
ddTotalNumberSwapping);
(void) fprintf(table->out,"#:M_SHUFFLE %8d: NI swaps\n",ddTotalNISwaps);
#endif
return(1);
} /* end of ddShuffle */
/**Function********************************************************************
Synopsis [Moves one variable up.]
Description [Takes a variable from position x and sifts it up to
position xLow; xLow should be less than or equal to x.
Returns 1 if successful; 0 otherwise]
SideEffects [None]
SeeAlso []
******************************************************************************/
static int
ddSiftUp(
DdManager * table,
int x,
int xLow)
{
int y;
int size;
y = cuddNextLow(table,x);
while (y >= xLow) {
size = cuddSwapInPlace(table,y,x);
if (size == 0) {
return(0);
}
x = y;
y = cuddNextLow(table,x);
}
return(1);
} /* end of ddSiftUp */
/**Function********************************************************************
Synopsis [Fixes the BDD variable group tree after a shuffle.]
Description [Fixes the BDD variable group tree after a
shuffle. Assumes that the order of the variables in a terminal node
has not been changed.]
SideEffects [Changes the BDD variable group tree.]
SeeAlso []
******************************************************************************/
static void
bddFixTree(
DdManager * table,
MtrNode * treenode)
{
if (treenode == NULL) return;
treenode->low = ((int) treenode->index < table->size) ?
table->perm[treenode->index] : treenode->index;
if (treenode->child != NULL) {
bddFixTree(table, treenode->child);
}
if (treenode->younger != NULL)
bddFixTree(table, treenode->younger);
if (treenode->parent != NULL && treenode->low < treenode->parent->low) {
treenode->parent->low = treenode->low;
treenode->parent->index = treenode->index;
}
return;
} /* end of bddFixTree */
/**Function********************************************************************
Synopsis [Updates the BDD variable group tree before a shuffle.]
Description [Updates the BDD variable group tree before a shuffle.
Returns 1 if successful; 0 otherwise.]
SideEffects [Changes the BDD variable group tree.]
SeeAlso []
******************************************************************************/
static int
ddUpdateMtrTree(
DdManager * table,
MtrNode * treenode,
int * perm,
int * invperm)
{
int i, size;
int index, level, minLevel, maxLevel, minIndex;
if (treenode == NULL) return(1);
minLevel = CUDD_MAXINDEX;
maxLevel = 0;
minIndex = -1;
/* i : level */
for (i = treenode->low; i < treenode->low + treenode->size; i++) {
index = table->invperm[i];
level = perm[index];
if (level < minLevel) {
minLevel = level;
minIndex = index;
}
if (level > maxLevel)
maxLevel = level;
}
size = maxLevel - minLevel + 1;
if (minIndex == -1) return(0);
if (size == treenode->size) {
treenode->low = minLevel;
treenode->index = minIndex;
} else {
return(0);
}
if (treenode->child != NULL) {
if (!ddUpdateMtrTree(table, treenode->child, perm, invperm))
return(0);
}
if (treenode->younger != NULL) {
if (!ddUpdateMtrTree(table, treenode->younger, perm, invperm))
return(0);
}
return(1);
}
/**Function********************************************************************
Synopsis [Checks the BDD variable group tree before a shuffle.]
Description [Checks the BDD variable group tree before a shuffle.
Returns 1 if successful; 0 otherwise.]
SideEffects [Changes the BDD variable group tree.]
SeeAlso []
******************************************************************************/
static int
ddCheckPermuation(
DdManager * table,
MtrNode * treenode,
int * perm,
int * invperm)
{
int i, size;
int index, level, minLevel, maxLevel;
if (treenode == NULL) return(1);
minLevel = table->size;
maxLevel = 0;
/* i : level */
for (i = treenode->low; i < treenode->low + treenode->size; i++) {
index = table->invperm[i];
level = perm[index];
if (level < minLevel)
minLevel = level;
if (level > maxLevel)
maxLevel = level;
}
size = maxLevel - minLevel + 1;
if (size != treenode->size)
return(0);
if (treenode->child != NULL) {
if (!ddCheckPermuation(table, treenode->child, perm, invperm))
return(0);
}
if (treenode->younger != NULL) {
if (!ddCheckPermuation(table, treenode->younger, perm, invperm))
return(0);
}
return(1);
}
ABC_NAMESPACE_IMPL_END