sparse_vector.hpp File Reference

Sparse vector for halo exchange and indexed data views. More...

#include <algorithm>
#include <cstddef>
#include <vector>
#include <openpfc/core/backend_tags.hpp>
#include <openpfc/core/databuffer.hpp>

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Classes
class	pfc::core::SparseVector< BackendTag, T >
	Sparse vector for indexed data views. More...

Typedefs
using	pfc::core::HostTag = backend::CpuTag

Functions
template<typename BackendTag , typename T >
bool	pfc::core::on_host (const SparseVector< BackendTag, T > &vec)
	Check if SparseVector is on host.

Detailed Description

Sparse vector for halo exchange and indexed data views.

SparseVector represents a sparse view into selected entries of a dense array. It contains:

• Sorted indices (exchanged once during setup)
• Values at those indices (exchanged every step)

Key optimization: Indices are sorted for optimal contiguous memory access.

Used for:

• Halo exchange in distributed memory
• Arbitrary subregion extraction
• Mask-based data selection

// Create sparse vector with indices
std::vector<size_t> indices = {2, 4, 6};
auto sparse = pfc::core::SparseVector<pfc::backend::CpuTag, double>(indices);
 
// Gather values from source array
std::vector<double> source = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0};
gather(sparse, source.data(), source.size());
 
// Scatter values to destination
std::vector<double> dest(7, 0.0);
scatter(sparse, dest.data(), dest.size());

See also

core/databuffer.hpp for underlying memory management

core/exchange.hpp for MPI communication

Author

OpenPFC Development Team

Date

2025