EdgeWeight two_way_fm::perform_refinement(PartitionConfig & cfg,
graph_access& G,
complete_boundary & boundary,
std::vector<NodeID> & lhs_start_nodes,
std::vector<NodeID> & rhs_start_nodes,
boundary_pair * pair,
NodeWeight & lhs_part_weight,
NodeWeight & rhs_part_weight,
EdgeWeight & cut,
bool & something_changed) {
PartitionConfig config = cfg;//copy it since we make changes on that
if(lhs_start_nodes.size() == 0 or rhs_start_nodes.size() == 0) return 0; // nothing to refine
quality_metrics qm;
ASSERT_NEQ(pair->lhs, pair->rhs);
ASSERT_TRUE(assert_directed_boundary_condition(G, boundary, pair->lhs, pair->rhs));
ASSERT_EQ( cut, qm.edge_cut(G, pair->lhs, pair->rhs));
refinement_pq* lhs_queue = NULL;
refinement_pq* rhs_queue = NULL;
if(config.use_bucket_queues) {
EdgeWeight max_degree = G.getMaxDegree();
lhs_queue = new bucket_pq(max_degree);
rhs_queue = new bucket_pq(max_degree);
} else {
lhs_queue = new maxNodeHeap();
rhs_queue = new maxNodeHeap();
}
init_queue_with_boundary(config, G, lhs_start_nodes, lhs_queue, pair->lhs, pair->rhs);
init_queue_with_boundary(config, G, rhs_start_nodes, rhs_queue, pair->rhs, pair->lhs);
queue_selection_strategy* topgain_queue_select = new queue_selection_topgain(config);
queue_selection_strategy* diffusion_queue_select = new queue_selection_diffusion(config);
queue_selection_strategy* diffusion_queue_select_block_target = new queue_selection_diffusion_block_targets(config);
vertex_moved_hashtable moved_idx;
std::vector<NodeID> transpositions;
EdgeWeight inital_cut = cut;
int max_number_of_swaps = (int)(boundary.getBlockNoNodes(pair->lhs) + boundary.getBlockNoNodes(pair->rhs));
int step_limit = (int)((config.fm_search_limit/100.0)*max_number_of_swaps);
step_limit = std::max(step_limit, 15);
int min_cut_index = -1;
refinement_pq* from_queue = 0;
refinement_pq* to_queue = 0;
PartitionID from = 0;
PartitionID to = 0;
NodeWeight * from_part_weight = 0;
NodeWeight * to_part_weight = 0;
stop_rule* st_rule = new easy_stop_rule();
partition_accept_rule* accept_partition = NULL;
if(config.initial_bipartitioning) {
accept_partition = new ip_partition_accept_rule(config, cut,lhs_part_weight, rhs_part_weight, pair->lhs, pair->rhs);
} else {
accept_partition = new normal_partition_accept_rule(config, cut,lhs_part_weight, rhs_part_weight);
}
queue_selection_strategy* q_select;
if(config.softrebalance || config.rebalance || config.initial_bipartitioning) {
if(config.initial_bipartitioning) {
q_select = diffusion_queue_select_block_target;
} else {
q_select = diffusion_queue_select;
}
} else {
q_select = topgain_queue_select;
}
//roll forwards
EdgeWeight best_cut = cut;
int number_of_swaps = 0;
for(number_of_swaps = 0; number_of_swaps < max_number_of_swaps; number_of_swaps++) {
if(st_rule->search_should_stop(min_cut_index, number_of_swaps, step_limit)) break;
if(lhs_queue->empty() && rhs_queue->empty()) {
break;
}
q_select->selectQueue(lhs_part_weight, rhs_part_weight,
pair->lhs, pair->rhs,
from,to,
lhs_queue, rhs_queue,
&from_queue, &to_queue);
if(!from_queue->empty()) {
Gain gain = from_queue->maxValue();
NodeID node = from_queue->deleteMax();
ASSERT_TRUE(moved_idx[node].index == NOT_MOVED);
boundary.setBlockNoNodes(from, boundary.getBlockNoNodes(from)-1);
boundary.setBlockNoNodes(to, boundary.getBlockNoNodes(to)+1);
if(from == pair->lhs) {
from_part_weight = &lhs_part_weight;
to_part_weight = &rhs_part_weight;
} else {
from_part_weight = &rhs_part_weight;
to_part_weight = &lhs_part_weight;
}
move_node(config, G, node, moved_idx,
from_queue, to_queue,
from, to,
pair,
from_part_weight, to_part_weight,
boundary);
cut -= gain;
if( accept_partition->accept_partition(config, cut, lhs_part_weight, rhs_part_weight, pair->lhs, pair->rhs, config.rebalance)) {
ASSERT_TRUE( cut <= best_cut || config.rebalance);
if( cut < best_cut ) {
something_changed = true;
}
best_cut = cut;
min_cut_index = number_of_swaps;
}
transpositions.push_back(node);
moved_idx[node].index = MOVED;
} else {
break;
}
}
ASSERT_TRUE(assert_directed_boundary_condition(G, boundary, pair->lhs, pair->rhs));
ASSERT_EQ( cut, qm.edge_cut(G, pair->lhs, pair->rhs));
//roll backwards
for(number_of_swaps--; number_of_swaps > min_cut_index; number_of_swaps--) {
ASSERT_TRUE(transpositions.size() > 0);
NodeID node = transpositions.back();
transpositions.pop_back();
PartitionID nodes_partition = G.getPartitionIndex(node);
if(nodes_partition == pair->lhs) {
from_queue = lhs_queue;
to_queue = rhs_queue;
from = pair->lhs;
to = pair->rhs;
from_part_weight = &lhs_part_weight;
to_part_weight = &rhs_part_weight;
} else {
from_queue = rhs_queue;
to_queue = lhs_queue;
from = pair->rhs;
to = pair->lhs;
from_part_weight = &rhs_part_weight;
to_part_weight = &lhs_part_weight;
}
boundary.setBlockNoNodes(from, boundary.getBlockNoNodes(from)-1);
boundary.setBlockNoNodes(to, boundary.getBlockNoNodes(to)+1);
move_node_back(config, G, node, moved_idx,
from_queue, to_queue,
from, to,
pair,
from_part_weight,
to_part_weight,
boundary);
}
//clean up
cut = best_cut;
boundary.setEdgeCut(pair, best_cut);
boundary.setBlockWeight(pair->lhs, lhs_part_weight);
boundary.setBlockWeight(pair->rhs, rhs_part_weight);
delete lhs_queue;
delete rhs_queue;
delete topgain_queue_select;
delete diffusion_queue_select;
delete diffusion_queue_select_block_target;
delete st_rule;
delete accept_partition;
ASSERT_EQ( cut, qm.edge_cut(G, pair->lhs, pair->rhs));
ASSERT_TRUE(assert_directed_boundary_condition(G, boundary, pair->lhs, pair->rhs));
ASSERT_TRUE( (int)inital_cut-(int)best_cut >= 0 || cfg.rebalance);
// the computed partition shouldnt have a edge cut which is worse than the initial one
return inital_cut-best_cut;
}
EdgeWeight kway_graph_refinement_core::single_kway_refinement_round_internal(PartitionConfig & config,
graph_access & G,
complete_boundary & boundary,
boundary_starting_nodes & start_nodes,
int step_limit,
vertex_moved_hashtable & moved_idx,
bool compute_touched_partitions,
std::unordered_map<PartitionID, PartitionID> & touched_blocks) {
commons = kway_graph_refinement_commons::getInstance(config);
refinement_pq* queue = NULL;
if(config.use_bucket_queues) {
EdgeWeight max_degree = G.getMaxDegree();
queue = new bucket_pq(max_degree);
} else {
queue = new maxNodeHeap();
}
init_queue_with_boundary(config, G, start_nodes, queue, moved_idx);
if(queue->empty()) {delete queue; return 0;}
std::vector<NodeID> transpositions;
std::vector<PartitionID> from_partitions;
std::vector<PartitionID> to_partitions;
int max_number_of_swaps = (int)(G.number_of_nodes());
int min_cut_index = -1;
EdgeWeight cut = std::numeric_limits<int>::max()/2; // so we dont need to compute the edge cut
EdgeWeight initial_cut = cut;
//roll forwards
EdgeWeight best_cut = cut;
int number_of_swaps = 0;
int movements = 0;
kway_stop_rule* stopping_rule = NULL;
switch(config.kway_stop_rule) {
case KWAY_SIMPLE_STOP_RULE:
stopping_rule = new kway_simple_stop_rule(config);
break;
case KWAY_ADAPTIVE_STOP_RULE:
stopping_rule = new kway_adaptive_stop_rule(config);
break;
}
for(number_of_swaps = 0, movements = 0; movements < max_number_of_swaps; movements++, number_of_swaps++) {
if( queue->empty() ) break;
if( stopping_rule->search_should_stop(min_cut_index, number_of_swaps, step_limit) ) break;
Gain gain = queue->maxValue();
NodeID node = queue->deleteMax();
#ifndef NDEBUG
PartitionID maxgainer;
EdgeWeight ext_degree;
ASSERT_TRUE(moved_idx[node].index == NOT_MOVED);
ASSERT_EQ(gain, commons->compute_gain(G, node, maxgainer, ext_degree));
ASSERT_TRUE(ext_degree > 0);
#endif
PartitionID from = G.getPartitionIndex(node);
bool successfull = move_node(config, G, node, moved_idx, queue, boundary);
if(successfull) {
cut -= gain;
stopping_rule->push_statistics(gain);
bool accept_equal = random_functions::nextBool();
if( cut < best_cut || ( cut == best_cut && accept_equal )) {
best_cut = cut;
min_cut_index = number_of_swaps;
if(cut < best_cut)
stopping_rule->reset_statistics();
}
from_partitions.push_back(from);
to_partitions.push_back(G.getPartitionIndex(node));
transpositions.push_back(node);
} else {
number_of_swaps--; //because it wasnt swaps
}
moved_idx[node].index = MOVED;
ASSERT_TRUE(boundary.assert_bnodes_in_boundaries());
ASSERT_TRUE(boundary.assert_boundaries_are_bnodes());
}
ASSERT_TRUE(boundary.assert_bnodes_in_boundaries());
ASSERT_TRUE(boundary.assert_boundaries_are_bnodes());
//roll backwards
for(number_of_swaps--; number_of_swaps>min_cut_index; number_of_swaps--) {
ASSERT_TRUE(transpositions.size() > 0);
NodeID node = transpositions.back();
transpositions.pop_back();
PartitionID to = from_partitions.back();
from_partitions.pop_back();
to_partitions.pop_back();
move_node_back(config, G, node, to, moved_idx, queue, boundary);
}
//reconstruct the touched partitions
if(compute_touched_partitions) {
ASSERT_EQ(from_partitions.size(), to_partitions.size());
for(unsigned i = 0; i < from_partitions.size(); i++) {
touched_blocks[from_partitions[i]] = from_partitions[i];
touched_blocks[to_partitions[i]] = to_partitions[i];
}
}
ASSERT_TRUE(boundary.assert_bnodes_in_boundaries());
ASSERT_TRUE(boundary.assert_boundaries_are_bnodes());
delete queue;
delete stopping_rule;
return initial_cut - best_cut;
}