AllToAllReduce(const Op& op_, const Assigner& assigner):
op(op_)
{
for (int gid = 0; gid < assigner.nblocks(); ++gid)
{
BlockID nbr = { gid, assigner.rank(gid) };
all_neighbors_link.add_neighbor(nbr);
}
}
void kdtree_sampling
(Master& master, //!< master object
const Assigner& assigner, //!< assigner object
int dim, //!< dimensionality
const ContinuousBounds& domain, //!< global data extents
std::vector<Point> Block::* points, //!< input points to sort into kd-tree
size_t samples, //!< number of samples to take in each block
bool wrap = false)//!< periodic boundaries in all dimensions
{
if (assigner.nblocks() & (assigner.nblocks() - 1))
{
fprintf(stderr, "KD-tree requires a number of blocks that's a power of 2, got %d\n", assigner.nblocks());
std::abort();
}
typedef diy::RegularContinuousLink RCLink;
for (size_t i = 0; i < master.size(); ++i)
{
RCLink* link = static_cast<RCLink*>(master.link(i));
*link = RCLink(dim, domain, domain);
if (wrap) // set up the links to self
{
diy::BlockID self = { master.gid(i), master.communicator().rank() };
for (int j = 0; j < dim; ++j)
{
diy::Direction dir, wrap_dir;
// left
dir.x[j] = -1; wrap_dir.x[j] = -1;
link->add_neighbor(self);
link->add_bounds(domain);
link->add_direction(dir);
link->add_wrap(wrap_dir);
// right
dir.x[j] = 1; wrap_dir.x[j] = 1;
link->add_neighbor(self);
link->add_bounds(domain);
link->add_direction(dir);
link->add_wrap(wrap_dir);
}
}
}
detail::KDTreeSamplingPartition<Block,Point> kdtree_partition(dim, points, samples);
detail::KDTreePartners partners(dim, assigner.nblocks(), wrap, domain);
reduce(master, assigner, partners, kdtree_partition);
// update master.expected to match the links
int expected = 0;
for (size_t i = 0; i < master.size(); ++i)
expected += master.link(i)->size_unique();
master.set_expected(expected);
}
void sort(Master& master, //!< master object
const Assigner& assigner, //!< assigner object
std::vector<T> Block::* values, //!< all values to sort
std::vector<T> Block::* samples, //!< (output) boundaries of blocks
size_t num_samples, //!< desired number of samples
const Cmp& cmp, //!< comparison function
int k = 2, //!< k-ary reduction will be used
bool samples_only = false) //!< false: results will be all_to_all exchanged; true: only sort but don't exchange results
{
bool immediate = master.immediate();
master.set_immediate(false);
// NB: although sorter will go out of scope, its member functions sample()
// and exchange() will return functors whose copies get saved inside reduce
detail::SampleSort<Block,T,Cmp> sorter(values, samples, cmp, num_samples);
// swap-reduce to all-gather samples
RegularDecomposer<DiscreteBounds> decomposer(1, interval(0,assigner.nblocks()), assigner.nblocks());
RegularSwapPartners partners(decomposer, k);
reduce(master, assigner, partners, sorter.sample(), detail::SkipIntermediate(partners.rounds()));
// all_to_all to exchange the values
if (!samples_only)
all_to_all(master, assigner, sorter.exchange(), k);
master.set_immediate(immediate);
}
void fix(const Assigner& assigner) { for (unsigned i = 0; i < neighbors_.size(); ++i) { neighbors_[i].proc = assigner.rank(neighbors_[i].gid); } }
