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fix vertex support in flat initial partitioning algorithms
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@kittobi1992
kittobi1992 committed Jul 27, 2023
1 parent 6c2a2d1 commit 0f0700a
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Showing 11 changed files with 372 additions and 116 deletions.
30 changes: 26 additions & 4 deletions mt-kahypar/partition/initial_partitioning/bfs_initial_partitioner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,8 @@ void BFSInitialPartitioner<TypeTraits>::partitionImpl() {
_ip_data.local_hyperedge_fast_reset_flag_array();

_ip_data.reset_unassigned_hypernodes(_rng);
parallel::scalable_vector<HypernodeID> start_nodes =
_ip_data.preassignFixedVertices(hypergraph);
vec<vec<HypernodeID>> start_nodes =
PseudoPeripheralStartNodes<TypeTraits>::computeStartNodes(_ip_data, _context, kInvalidPartition, _rng);

// Insert each start node for each block into its corresponding queue
Expand All @@ -52,23 +53,27 @@ void BFSInitialPartitioner<TypeTraits>::partitionImpl() {
parallel::scalable_vector<Queue> queues(_context.partition.k);

for (PartitionID block = 0; block < _context.partition.k; ++block) {
queues[block].push(start_nodes[block]);
markHypernodeAsInQueue(hypergraph, hypernodes_in_queue, start_nodes[block], block);
for ( const HypernodeID& hn : start_nodes[block] ) {
queues[block].push(hn);
markHypernodeAsInQueue(hypergraph, hypernodes_in_queue, hn, block);
}
}

HypernodeID num_assigned_hypernodes = 0;
// We grow the k blocks of the partition starting from each start node in
// a BFS-fashion. The BFS queues for each block are visited in round-robin-fashion.
// Once a block is on turn, it pops it first hypernode and pushes
// all adjacent vertices into its queue.
HypernodeID num_assigned_hypernodes = _ip_data.numFixedVertices();
const HypernodeID current_num_nodes =
hypergraph.initialNumNodes() - hypergraph.numRemovedHypernodes();
while (num_assigned_hypernodes < current_num_nodes) {
for (PartitionID block = 0; block < _context.partition.k; ++block) {
HypernodeID hn = kInvalidHypernode;

bool fits_into_block = false;
while (!queues[block].empty()) {
const HypernodeID next_hn = queues[block].front();
ASSERT(!hypergraph.isFixed(next_hn));
queues[block].pop();

if (hypergraph.partID(next_hn) == kInvalidPartition) {
Expand All @@ -80,6 +85,7 @@ void BFSInitialPartitioner<TypeTraits>::partitionImpl() {
// Note, in that case the balanced constraint will be violated.
hn = next_hn;
if (fitsIntoBlock(hypergraph, hn, block)) {
fits_into_block = true;
break;
}
}
Expand All @@ -90,6 +96,22 @@ void BFSInitialPartitioner<TypeTraits>::partitionImpl() {
// assigned to an other block or the hypergraph is unconnected, we
// choose an new unassigned hypernode (if one exists)
hn = _ip_data.get_unassigned_hypernode();
if ( hn != kInvalidHypernode && fitsIntoBlock(hypergraph, hn, block) ) {
fits_into_block = true;
}
}

if ( hn != kInvalidHypernode && !fits_into_block ) {
// The node does not fit into the block. Thus, we quickly
// check if there is another block to which we can assign the node
for ( PartitionID other_block = 0; other_block < _context.partition.k; ++other_block ) {
if ( other_block != block && fitsIntoBlock(hypergraph, hn, other_block) ) {
// There is another block to which we can assign the node
// => ignore the node for now
hn = kInvalidHypernode;
break;
}
}
}

if (hn != kInvalidHypernode) {
Expand Down
14 changes: 10 additions & 4 deletions mt-kahypar/partition/initial_partitioning/greedy_initial_partitioner.h
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Original file line number Diff line number Diff line change
Expand Up @@ -72,23 +72,28 @@ class GreedyInitialPartitioner : public IInitialPartitioner {
// initial partitioner. E.g. the round-robin variant leaves the hypernode
// unassigned, but the global and sequential strategy both preassign
// all vertices to block 1 before initial partitioning.
_ip_data.preassignFixedVertices(hg);
if ( _default_block != kInvalidPartition ) {
ASSERT(_default_block < _context.partition.k);
kway_pq.disablePart(_default_block);
for ( const HypernodeID& hn : hg.nodes() ) {
hg.setNodePart(hn, _default_block);
if ( !hg.isFixed(hn) ) {
hg.setNodePart(hn, _default_block);
}
}
}

// Insert start vertices into its corresponding PQs
_ip_data.reset_unassigned_hypernodes(_rng);
parallel::scalable_vector<HypernodeID> start_nodes =
vec<vec<HypernodeID>> start_nodes =
PseudoPeripheralStartNodes<TypeTraits>::computeStartNodes(_ip_data, _context, _default_block, _rng);
ASSERT(static_cast<size_t>(_context.partition.k) == start_nodes.size());
kway_pq.clear();
for ( PartitionID block = 0; block < _context.partition.k; ++block ) {
if ( block != _default_block ) {
insertVertexIntoPQ(hg, kway_pq, start_nodes[block], block);
for ( const HypernodeID& hn : start_nodes[block] ) {
insertVertexIntoPQ(hg, kway_pq, hn, block);
}
}
}

Expand Down Expand Up @@ -221,7 +226,8 @@ class GreedyInitialPartitioner : public IInitialPartitioner {
for ( const HyperedgeID& he : hypergraph.incidentEdges(hn)) {
if ( !hyperedges_in_queue[to * hypergraph.initialNumEdges() + he] ) {
for ( const HypernodeID& pin : hypergraph.pins(he) ) {
if ( hypergraph.partID(pin) == _default_block && !pq.contains(pin, to) ) {
if ( hypergraph.partID(pin) == _default_block &&
!pq.contains(pin, to) && !hypergraph.isFixed(pin) ) {
insertVertexIntoPQ(hypergraph, pq, pin, to);
}
}
Expand Down
37 changes: 35 additions & 2 deletions mt-kahypar/partition/initial_partitioning/initial_partitioning_data_container.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@
#include "mt-kahypar/parallel/stl/scalable_vector.h"
#include "mt-kahypar/utils/cast.h"
#include "mt-kahypar/utils/utilities.h"
#include "mt-kahypar/utils/range.h"
#include "mt-kahypar/partition/refinement/fm/sequential_twoway_fm_refiner.h"
#include "mt-kahypar/partition/refinement/gains/gain_cache_ptr.h"

Expand Down Expand Up @@ -350,6 +351,7 @@ class InitialPartitioningDataContainer {

using ThreadLocalHypergraph = tbb::enumerable_thread_specific<LocalInitialPartitioningHypergraph>;
using ThreadLocalUnassignedHypernodes = tbb::enumerable_thread_specific<parallel::scalable_vector<HypernodeID>>;
using FixedVertexIterator = typename vec<HypernodeID>::const_iterator;

public:
InitialPartitioningDataContainer(PartitionedHypergraph& hypergraph,
Expand All @@ -368,6 +370,7 @@ class InitialPartitioningDataContainer {
_local_he_visited(_context.partition.k * hypergraph.initialNumEdges()),
_local_unassigned_hypernodes(),
_local_unassigned_hypernode_pointer(std::numeric_limits<size_t>::max()),
_fixed_vertices(),
_max_pop_size(_context.initial_partitioning.population_size) {
// Setup Label Propagation IRefiner Config for Initial Partitioning
_context.refinement = _context.initial_partitioning.refinement;
Expand All @@ -379,6 +382,14 @@ class InitialPartitioningDataContainer {
_best_partitions[i].second.resize(hypergraph.initialNumNodes(), kInvalidPartition);
}
}

if ( _partitioned_hg.hasFixedVertices() ) {
for ( const HypernodeID& hn : _partitioned_hg.nodes() ) {
if ( _partitioned_hg.isFixed(hn) ) {
_fixed_vertices.push_back(hn);
}
}
}
}

InitialPartitioningDataContainer(const InitialPartitioningDataContainer&) = delete;
Expand Down Expand Up @@ -434,7 +445,9 @@ class InitialPartitioningDataContainer {
// we initialize it here
const PartitionedHypergraph& hypergraph = local_partitioned_hypergraph();
for ( const HypernodeID& hn : hypergraph.nodes() ) {
unassigned_hypernodes.push_back(hn);
if ( !hypergraph.isFixed(hn) ) {
unassigned_hypernodes.push_back(hn);
}
}
std::shuffle(unassigned_hypernodes.begin(), unassigned_hypernodes.end(), prng);
}
Expand All @@ -452,7 +465,8 @@ class InitialPartitioningDataContainer {
while ( unassigned_hypernode_pointer > 0 ) {
const HypernodeID current_hn = unassigned_hypernodes[0];
// In case the current hypernode is unassigned we return it
if ( hypergraph.partID(current_hn) == unassigned_block ) {
if ( hypergraph.partID(current_hn) == unassigned_block &&
!hypergraph.isFixed(current_hn) ) {
return current_hn;
}
// In case the hypernode on the first position is already assigned,
Expand Down Expand Up @@ -651,6 +665,24 @@ class InitialPartitioningDataContainer {
_context.utility_id).add_initial_partitioning_result(best_flat_algo, number_of_threads, stats);
}

IteratorRange<FixedVertexIterator> fixedVertices() const {
return IteratorRange<FixedVertexIterator>(
_fixed_vertices.cbegin(), _fixed_vertices.cend());
}

HypernodeID numFixedVertices() const {
return _fixed_vertices.size();
}

void preassignFixedVertices(PartitionedHypergraph& hypergraph) {
if ( hypergraph.hasFixedVertices() ) {
for ( const HypernodeID& hn : fixedVertices() ) {
ASSERT(hypergraph.isFixed(hn));
hypergraph.setNodePart(hn, hypergraph.fixedVertexBlock(hn));
}
}
}

private:
LocalInitialPartitioningHypergraph construct_local_partitioned_hypergraph() {
return LocalInitialPartitioningHypergraph(
Expand All @@ -671,6 +703,7 @@ class InitialPartitioningDataContainer {
ThreadLocalFastResetFlagArray _local_he_visited;
ThreadLocalUnassignedHypernodes _local_unassigned_hypernodes;
tbb::enumerable_thread_specific<size_t> _local_unassigned_hypernode_pointer;
vec<HypernodeID> _fixed_vertices;

size_t _max_pop_size;
SpinLock _pop_lock;
Expand Down
86 changes: 54 additions & 32 deletions mt-kahypar/partition/initial_partitioning/label_propagation_initial_partitioner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -40,20 +40,46 @@ void LabelPropagationInitialPartitioner<TypeTraits>::partitionImpl() {
HighResClockTimepoint start = std::chrono::high_resolution_clock::now();
PartitionedHypergraph& hg = _ip_data.local_partitioned_hypergraph();

_ip_data.reset_unassigned_hypernodes(_rng);

parallel::scalable_vector<HypernodeID> start_nodes =
_ip_data.reset_unassigned_hypernodes(_rng);
_ip_data.preassignFixedVertices(hg);
vec<vec<HypernodeID>> start_nodes =
PseudoPeripheralStartNodes<TypeTraits>::computeStartNodes(_ip_data, _context, kInvalidPartition, _rng);
for ( PartitionID block = 0; block < _context.partition.k; ++block ) {
if ( hg.partID(start_nodes[block]) == kInvalidPartition ) {
hg.setNodePart(start_nodes[block], block);
size_t i = 0;
for ( ; i < std::min(start_nodes[block].size(),
_context.initial_partitioning.lp_initial_block_size); ++i ) {
const HypernodeID hn = start_nodes[block][i];
if ( hg.partID(hn) == kInvalidPartition && fitsIntoBlock(hg, hn, block) ) {
hg.setNodePart(hn, block);
} else {
std::swap(start_nodes[block][i--], start_nodes[block][start_nodes[block].size() - 1]);
start_nodes[block].pop_back();
}
}

// Remove remaining unassigned seed nodes
for ( ; i < start_nodes[block].size(); ++i ) {
start_nodes[block].pop_back();
}

if ( start_nodes[block].size() == 0 ) {
// There has been no seed node assigned to the block
// => find an unassigned node and assign it to the block
const HypernodeID hn = _ip_data.get_unassigned_hypernode();
if ( hn != kInvalidHypernode ) {
hg.setNodePart(hn, block);
start_nodes[block].push_back(hn);
}
}
}

// Each block is extended with 5 additional vertices which are adjacent
// to their corresponding seed vertices. This should prevent that block
// becomes empty after several label propagation rounds.
for ( PartitionID block = 0; block < _context.partition.k; ++block ) {
if ( hg.partID(start_nodes[block]) == block ) {
if ( !start_nodes[block].empty() && start_nodes[block].size() <
_context.initial_partitioning.lp_initial_block_size ) {
extendBlockToInitialBlockSize(hg, start_nodes[block], block);
}
}
Expand All @@ -63,8 +89,7 @@ void LabelPropagationInitialPartitioner<TypeTraits>::partitionImpl() {
converged = true;

for ( const HypernodeID& hn : hg.nodes() ) {

if (hg.nodeDegree(hn) > 0) {
if (hg.nodeDegree(hn) > 0 && !hg.isFixed(hn)) {
// Assign vertex to the block where FM gain is maximized
MaxGainMove max_gain_move = computeMaxGainMove(hg, hn);

Expand Down Expand Up @@ -238,42 +263,39 @@ MaxGainMove LabelPropagationInitialPartitioner<TypeTraits>::findMaxGainMove(Part

template<typename TypeTraits>
void LabelPropagationInitialPartitioner<TypeTraits>::extendBlockToInitialBlockSize(PartitionedHypergraph& hypergraph,
HypernodeID seed_vertex,
const vec<HypernodeID>& seed_vertices,
const PartitionID block) {
ASSERT(hypergraph.partID(seed_vertex) == block);
size_t block_size = 1;
ASSERT(seed_vertices.size() > 0);
size_t block_size = seed_vertices.size();

while (block_size < _context.initial_partitioning.lp_initial_block_size) {

// We search for _context.initial_partitioning.lp_initial_block_size vertices
// around the seed vertex to extend the corresponding block
// We search for _context.initial_partitioning.lp_initial_block_size vertices
// around the seed vertex to extend the corresponding block
for ( const HypernodeID& seed_vertex : seed_vertices ) {
for ( const HyperedgeID& he : hypergraph.incidentEdges(seed_vertex) ) {
for ( const HypernodeID& pin : hypergraph.pins(he) ) {
if ( hypergraph.partID(pin) == kInvalidPartition ) {
if ( hypergraph.partID(pin) == kInvalidPartition &&
fitsIntoBlock(hypergraph, pin, block) ) {
hypergraph.setNodePart(pin, block);
block_size++;
if ( block_size >= _context.initial_partitioning.lp_initial_block_size ) {
break;
}
if ( block_size >= _context.initial_partitioning.lp_initial_block_size ) break;
}
}
if ( block_size >= _context.initial_partitioning.lp_initial_block_size ) {
break;
}
if ( block_size >= _context.initial_partitioning.lp_initial_block_size ) break;
}
if ( block_size >= _context.initial_partitioning.lp_initial_block_size ) break;
}


// If there are less than _context.initial_partitioning.lp_initial_block_size
// adjacent vertices to the seed vertex, we find a new seed vertex and call
// this function recursive
if ( block_size < _context.initial_partitioning.lp_initial_block_size ) {
seed_vertex = _ip_data.get_unassigned_hypernode();
if ( seed_vertex != kInvalidHypernode ) {
hypergraph.setNodePart(seed_vertex, block);
block_size++;
} else {
break;
}
// If there are less than _context.initial_partitioning.lp_initial_block_size
// adjacent vertices to the seed vertex, we find a new seed vertex and call
// this function recursive
while ( block_size < _context.initial_partitioning.lp_initial_block_size ) {
const HypernodeID seed_vertex = _ip_data.get_unassigned_hypernode();
if ( seed_vertex != kInvalidHypernode && fitsIntoBlock(hypergraph, seed_vertex, block) ) {
hypergraph.setNodePart(seed_vertex, block);
block_size++;
} else {
break;
}
}
}
Expand Down
2 changes: 1 addition & 1 deletion mt-kahypar/partition/initial_partitioning/label_propagation_initial_partitioner.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -92,7 +92,7 @@ class LabelPropagationInitialPartitioner : public IInitialPartitioner {
const HypernodeWeight internal_weight);

void extendBlockToInitialBlockSize(PartitionedHypergraph& hypergraph,
HypernodeID seed_vertex,
const vec<HypernodeID>& seed_vertices,
const PartitionID block);

void assignVertexToBlockWithMinimumWeight(PartitionedHypergraph& hypergraph,
Expand Down
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