void nqueens_rec(int column, list_node* head) {
cilk_for (int i=0; i<SIZE; i++) {
if (addok(head, i, column)) {
// add the node
list_node new_node;
new_node.next = head;
new_node.row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, &new_node);
else
nqueens_rec(column+1, &new_node);
#else
nqueens_rec(column+1, &new_node);
#endif
} else { // found a solution
//solution_count += 1;
}
}
// else do nothing -- dead computation branch
}
}
void operator () (const tbb::blocked_range<int> &range) const {
for(int i=range.begin(); i<range.end(); i++) {
list_node *node;
if (addok(head, i, column)) {
// add the node
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#endif
list_node new_node;
new_node.next = head;
new_node.row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, &new_node);
else
nqueens_rec(column+1, &new_node);
#else
nqueens_rec(column+1, &new_node);
#endif
} else { // found a solution
//solution = &new_node;
solution_count++; //atomic
//abort()
}
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
}
#endif
} // end if addok
// else do nothing -- dead computation branch
}
}
int nqueens() {
solution_count = 0;
#ifdef CUTOFF
if (0>=CUTOFF_LEVEL)
ser_nqueens_rec(0, NULL);
else
nqueens_rec(0, NULL);
#else
nqueens_rec(0, NULL);
#endif
return solution_count;
}
void operator () (tbb::blocked_range<int> &range, tbb::task* parent_task) const {
tbb::blocked_range<int> subrange = range.get_some_safe();
long savedcnt = 0;
//while ( subrange.empty() == false && parent_task->bflws_pushed == false) {
while ( subrange.empty() == false ) {
for(int i=subrange.begin(); i<subrange.end(); i++) {
list_node *node;
if (addok(head, i, column)) {
// add the node
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#endif
list_node new_node;
new_node.next = head;
new_node.row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, &new_node);
else
nqueens_rec(column+1, &new_node, parent_task);
#else
nqueens_rec(column+1, &new_node, parent_task);
#endif
} else { // found a solution
//solution = &new_node;
solution_count++; //atomic
//abort()
}
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
}
#endif
} // end if addok
// else do nothing -- dead computation branch
} // end for-loop over range
#ifdef DEQUE_THRESH
if ( parent_task->task_pool_size() < DEQUE_THRESH) break;
#else
if ( parent_task->is_task_pool_empty() ) break;
#endif
subrange = range.get_some_safe();
//printf("Saved one ping-pong!\n");
//std::cout << "Saved one\n" ;
//savedcnt ++;
} // end while
//printf("Saved %d ping-pongs\n", savedcnt);
//std::cout << "Saved " << savedcnt << "\n" ;
}
void operator () (tbb::blocked_range<int> &range, tbb::task* parent_task) const {
//int cnt = 0;
for(int i = range.begin(); i < range.end() /*&& parent_task->bflws_pushed == false*/; i++) {
range.remove_some_safe();
list_node *node;
if (addok(head, i, column)) {
// add the node
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#endif
list_node new_node;
new_node.next = head;
new_node.row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, &new_node);
else
nqueens_rec(column+1, &new_node, parent_task);
#else
nqueens_rec(column+1, &new_node, parent_task);
#endif
} else { // found a solution
//solution = &new_node;
solution_count++; //atomic
//abort()
}
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
}
#endif
} // end if addok
// else do nothing -- dead computation branch
//cnt++;
//if (cnt == GRAINSIZE)) {
//cnt = 0;
//subrange = range.remove_some_safe();
DEQUE_CHECK_CODE (parent_task);
//else end = range.end();
//}
//printf("Saved one ping-pong!\n");
//std::cout << "Saved one\n" ;
//savedcnt ++;
//i++;
} // end for-loop over range
//printf("Saved %d ping-pongs\n", savedcnt);
//std::cout << "Saved " << savedcnt << "\n" ;
}
void nqueens() {
//solution_count.set_value(0);
nqueens_rec(0, NULL);
}
int nqueens() {
solution_count = 0;
nqueens_rec(0, NULL, NULL);
return solution_count;
}
void nqueens_rec(int column, list_node* head, tbb::task* parent_task) {
PARTITIONER partitioner;
tbb::blocked_range<int> range(0,SIZE,GRAINSIZE);
#ifdef _TBB_MELD_ALLOW_CODE_DUPLICATION
for(int i = range.begin(); i < range.end() /*&& parent_task->bflws_pushed == false*/; i++) {
// DEQUE CHECK
if ( parent_task==NULL || parent_task->is_task_pool_empty() ) {
tbb::parallel_for (range, nqueensMeldFlatBody(column,head), partitioner);
break;
} // else
range.remove_some_safe();
list_node *node;
if (addok(head, i, column)) {
// add the node
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#endif
list_node new_node;
new_node.next = head;
new_node.row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, &new_node);
else
nqueens_rec(column+1, &new_node, parent_task);
#else
nqueens_rec(column+1, &new_node, parent_task);
#endif
} else { // found a solution
//solution = &new_node;
solution_count++; //atomic
//abort()
}
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
}
#endif
} // end if addok
} // end for-loop over range
#else // TBB_MELD_DONT_ALLOW_CODE_DUPLICATION
nqueensMeldFlatBody body(column,head);
// create task
//start_for<tbb::blocked_range<int>, nqueensMeldFlatBody, PARTITIONER> *self = NULL;
//self = new(task::allocate_root()) start_for(range,body,const_cast<PARTITIONER&>(partitioner));
start_for<tbb::blocked_range<int>, nqueensMeldFlatBody, PARTITIONER>& a = *new(task::allocate_root()) start_for(range,body,const_cast<Partitioner&>(partitioner));
// add to postponed deque
self->next_postponed = NULL;
// enqueue postponed task
tbb::task* saved_tail = self->push_postponed_task();
do {
//if ( parent_task==NULL || parent_task->is_task_pool_empty() ) {
if ( self->is_task_pool_empty() ) {
// TODO: optim if possible split ancestor postponed and continue:
// note: this will always be possible since we already added it to
// the postponed deque.
parallel_for (range, body, partitioner);
break;
} // else
body(range,parent_task);
} while(range.empty()==false);
// TODO detect if a split has occurred, in which case some synchronization is needed
#endif
}
void ser_nqueens_rec(int column, list_node* head) {
int i;
for (i=0; i<SIZE; i++) {
list_node *node;
if (addok(head, i, column)) {
// add the node
node = (list_node*)scalable_malloc(sizeof(list_node));
#ifdef DEBUG
if(node==NULL) out_of_memory = 1;
#endif
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#else // Don't quit. Instead keep scanning the whole search space.
if (node!=NULL) {
#endif
node->next = head;
node->row = i;
if (column+1<SIZE) {
ser_nqueens_rec(column+1, node);
} else { // found a solution
//solution = node;
solution_count++; // atomic
}
}
}
// else do nothing -- dead computation branch
}
}
void nqueens_rec(int column, list_node* head);
class nqueensBody {
public:
int column;
list_node* head;
void operator () (const tbb::blocked_range<int> &range) const {
for(int i=range.begin(); i<range.end(); i++) {
list_node *node;
if (addok(head, i, column)) {
// add the node
node = (list_node*)scalable_malloc(sizeof(list_node));
#ifdef DEBUG
if(node==NULL) out_of_memory = 1;
#endif
#ifdef QUIT_ON_SOLUTION // QUIT as soon as a solution is found
if (node!=NULL && solution == NULL) {
#else // Don't quit. Instead keep scanning the whole search space.
if (node!=NULL) {
#endif
node->next = head;
node->row = i;
if (column+1<SIZE) {
#ifdef CUTOFF
if (column+1>=CUTOFF_LEVEL)
ser_nqueens_rec(column+1, node);
else
nqueens_rec(column+1, node);
#else
nqueens_rec(column+1, node);
#endif
} else { // found a solution
//solution = node;
solution_count++; //atomic
//abort()
}
}
} // end if addok
// else do nothing -- dead computation branch
}
}
// Constructor
nqueensBody(int col, list_node* hd) : column(col), head(hd) { }
};
void nqueens_rec(int column, list_node* head) {
#ifdef TWOLVL_SCHED
tbb::auto_partitioner firstLevelPartitioner;
PARTITIONER partitioner;
// tbb::parallel_for (tbb::blocked_range<int>(0,SIZE,GRAINSIZE), nqueensBody(column,head), ((column==0)?firstLevelPartitioner:partitioner) );
if (column==0)
tbb::parallel_for (tbb::blocked_range<int>(0,SIZE,GRAINSIZE), nqueensBody(column,head), firstLevelPartitioner );
else
tbb::parallel_for (tbb::blocked_range<int>(0,SIZE,GRAINSIZE), nqueensBody(column,head), partitioner );
#else
PARTITIONER partitioner;
tbb::parallel_for (tbb::blocked_range<int>(0,SIZE,GRAINSIZE), nqueensBody(column,head), partitioner);
#endif
}
