Bitset#

#include <raft/core/bitset.cuh>

namespace raft::core

template<typename bitset_t = uint32_t, typename index_t = uint32_t>
struct bitset_view#

View of a RAFT Bitset.

This lightweight structure stores a pointer to a bitset in device memory with it’s length. It provides a test() device function to check if a given index is set in the bitset.

Template Parameters:

  • bitset_t – Underlying type of the bitset array. Default is uint32_t.

  • index_t – Indexing type used. Default is uint32_t.

Public Functions

inline _RAFT_HOST_DEVICE bitset_view(raft::device_vector_view<bitset_t, index_t> bitset_span, index_t bitset_len)#

Create a bitset view from a device vector view of the bitset.

Parameters:

  • bitset_span – Device vector view of the bitset

  • bitset_len – Number of bits in the bitset

inline _RAFT_DEVICE auto test(const index_t sample_index) const -> bool#

Device function to test if a given index is set in the bitset.

Parameters:

sample_index – Single index to test

Returns:

bool True if index has not been unset in the bitset

inline _RAFT_DEVICE auto operator[](const index_t sample_index) const -> bool#

Device function to test if a given index is set in the bitset.

Parameters:

sample_index – Single index to test

Returns:

bool True if index has not been unset in the bitset

inline _RAFT_DEVICE void set (const index_t sample_index, bool set_value) const

Device function to set a given index to set_value in the bitset.

Parameters:

  • sample_index – index to set

  • set_value – Value to set the bit to (true or false)

inline _RAFT_HOST_DEVICE auto data() -> bitset_t*#

Get the device pointer to the bitset.

inline _RAFT_HOST_DEVICE auto size() const -> index_t#

Get the number of bits of the bitset representation.

inline _RAFT_HOST_DEVICE auto n_elements() const -> index_t#

Get the number of elements used by the bitset representation.

template<typename bitset_t = uint32_t, typename index_t = uint32_t>
struct bitset#

RAFT Bitset.

This structure encapsulates a bitset in device memory. It provides a view() method to get a device-usable lightweight view of the bitset. Each index is represented by a single bit in the bitset. The total number of bytes used is ceil(bitset_len / 8).

Template Parameters:

  • bitset_t – Underlying type of the bitset array. Default is uint32_t.

  • index_t – Indexing type used. Default is uint32_t.

Public Functions

inline bitset(const raft::resources &res, raft::device_vector_view<const index_t, index_t> mask_index, index_t bitset_len, bool default_value = true)#

Construct a new bitset object with a list of indices to unset.

Parameters:

  • res – RAFT resources

  • mask_index – List of indices to unset in the bitset

  • bitset_len – Length of the bitset

  • default_value – Default value to set the bits to. Default is true.

inline bitset(const raft::resources &res, index_t bitset_len, bool default_value = true)#

Construct a new bitset object.

Parameters:

  • res – RAFT resources

  • bitset_len – Length of the bitset

  • default_value – Default value to set the bits to. Default is true.

inline auto view() -> raft::core::bitset_view<bitset_t, index_t>#

Create a device-usable view of the bitset.

Returns:

bitset_view<bitset_t, index_t>

inline auto data() -> bitset_t*#

Get the device pointer to the bitset.

inline auto size() const -> index_t#

Get the number of bits of the bitset representation.

inline auto n_elements() const -> index_t#

Get the number of elements used by the bitset representation.

inline auto to_mdspan() -> raft::device_vector_view<bitset_t, index_t>#

Get an mdspan view of the current bitset.

inline void resize(const raft::resources &res, index_t new_bitset_len, bool default_value = true)#

Resize the bitset. If the requested size is larger, new memory is allocated and set to the default value.

Parameters:

  • res – RAFT resources

  • new_bitset_len – new size of the bitset

  • default_value – default value to initialize the new bits to

template<typename output_t = bool>
inline void test(const raft::resources &res, raft::device_vector_view<const index_t, index_t> queries, raft::device_vector_view<output_t, index_t> output) const#

Test a list of indices in a bitset.

Template Parameters:

output_t – Output type of the test. Default is bool.

Parameters:

  • res – RAFT resources

  • queries – List of indices to test

  • output – List of outputs

inline void set(const raft::resources &res, raft::device_vector_view<const index_t, index_t> mask_index, bool set_value = false)#

Set a list of indices in a bitset to set_value.

Parameters:

  • res – RAFT resources

  • mask_index – indices to remove from the bitset

  • set_value – Value to set the bits to (true or false)

inline void flip(const raft::resources &res)#

Flip all the bits in a bitset.

Parameters:

res – RAFT resources

inline void reset(const raft::resources &res, bool default_value = true)#

Reset the bits in a bitset.

Parameters:

  • res – RAFT resources

  • default_value – Value to set the bits to (true or false)

inline void count(const raft::resources &res, raft::device_scalar_view<index_t> count_gpu_scalar)#

Returns the number of bits set to true in count_gpu_scalar.

Parameters:

  • res – [in] RAFT resources

  • count_gpu_scalar – [out] Device scalar to store the count

inline auto count(const raft::resources &res) -> index_t#

Returns the number of bits set to true.

Parameters:

res – RAFT resources

Returns:

index_t Number of bits set to true

inline bool any(const raft::resources &res)#

Checks if any of the bits are set to true in the bitset.

Parameters:

res – RAFT resources

inline bool all(const raft::resources &res)#

Checks if all of the bits are set to true in the bitset.

Parameters:

res – RAFT resources

inline bool none(const raft::resources &res)#

Checks if none of the bits are set to true in the bitset.

Parameters:

res – RAFT resources