Bitset

Header file: <Kokkos_Bitset.hpp>

Class Interface

template<typename Device>
class Bitset

Kokkos::Bitset represents a thread safe view to a fixed-size (at run-time) sequence of N bits.

Template Parameters:

Device – Device that physically contains the bits.

Static Constants

static constexpr unsigned BIT_SCAN_REVERSE = 1u

BIT_SCAN_REVERSE : Bit mask for scanning direction

static constexpr unsigned MOVE_HINT_BACKWARD = 2u

MOVE_HINT_BACKWARD : Bit mask for hint direction

static constexpr unsigned BIT_SCAN_FORWARD_MOVE_HINT_FORWARD = 0u

BIT_SCAN_FORWARD_MOVE_HINT_FORWARD : When passed as scan_direction to find_any_set_near(...) or find_any_reset_near(...), scans for the bit in the forward (increasing index) direction. If the bit was not found, selects a new hint past the current hint.

static constexpr unsigned BIT_SCAN_REVERSE_MOVE_HINT_FORWARD = BIT_SCAN_REVERSE

BIT_SCAN_REVERSE_MOVE_HINT_FORWARD: When passed as scan_direction to find_any_set_near(...) or find_any_reset_near(...), scans for the bit in the reverse (decreasing index) direction. If the bit was not found, selects a new hint past the current hint.

static constexpr unsigned BIT_SCAN_FORWARD_MOVE_HINT_BACKWARD = MOVE_HINT_BACKWARD

BIT_SCAN_FORWARD_MOVE_HINT_BACKWARD: When passed as scan_direction to find_any_set_near(...) or find_any_reset_near(...), scans for the bit in the forward (increasing index) direction. If the bit was not found, selects a new hint before the current hint.

static constexpr unsigned BIT_SCAN_REVERSE_MOVE_HINT_BACKWARD = BIT_SCAN_REVERSE | MOVE_HINT_BACKWARD

BIT_SCAN_REVERSE_MOVE_HINT_BACKWARD: When passed as scan_direction to find_any_set_near(...) or find_any_reset_near(...), scans for the bit in the reverse (decreasing index) direction. If the bit was not found, selects a new hint before the current hint.

Constructors

Bitset(unsigned arg_size = 0u)

Host/Device: Construct a bitset with arg_size bits.

Data Access Functions

unsigned size() const

Host/Device: return the number of bits.

unsigned count() const

Host: return the number of bits which are set to 1.

void set()

Host: set all the bits to 1.

void reset();

void clear();

Host/Device: set all the bits to 0.

void set(unsigned i)

Device: set the i‘th bit to 1.

void reset(unsigned i)

Device: set the i‘th bit to 0.

bool test(unsigned i) const

Device: return true if and only if the i‘th bit is set to 1.

unsigned max_hint() const

Host/Device: used with find_any_set_near(...) & find_any_reset_near(...) functions.

Returns the max number of times those functions should be call when searching for an available bit.

Kokkos::pair<bool, unsigned> find_any_set_near(unsigned hint, unsigned scan_direction = BIT_SCAN_FORWARD_MOVE_HINT_FORWARD) const

Host/Device: starting at the hint position, find the first bit set to 1.

Returns a pair<bool, unsigned>.

When result.first is true then result.second is the bit position found.

When result.first is false then result.second is a new hint position.

If scan_direction & BIT_SCAN_REVERSE, then the scanning for the bit happens in decreasing index order; otherwise, it happens in increasing index order.

If scan_direction & MOVE_HINT_BACKWARDS, then the new hint position occurs at a smaller index than hint; otherwise, it occurs at a larger index than hint.

Kokkos::pair<bool, unsigned> find_any_unset_near(unsigned hint, unsigned scan_direction = BIT_SCAN_FORWARD_MOVE_HINT_FORWARD) const;

Host/Device: starting at the hint position, find the first bit set to 0.

Returns a pair<bool, unsigned>.

When result.first is true then result.second is the bit position found.

When result.first is false then result.second is a new hint position.

If scan_direction & BIT_SCAN_REVERSE, then the scanning for the bit happens in decreasing index order; otherwise, it happens in increasing index order.

If scan_direction & MOVE_HINT_BACKWARDS, then the new hint position occurs at a smaller index than hint; otherwise, it occurs at a larger index than hint.

constexpr bool is_allocated() const

Host/Device: the bits are allocated on the device.

ConstBitset

Class Interface

template<typename Device>
class ConstBitset

Template Parameters:

Device – Device that physically contains the bits.

Constructors / assignment

ConstBitset()

Host/Device: Construct a bitset with no bits.

ConstBitset(ConstBitset const &rhs) = default

ConstBitset &operator=(ConstBitset const &rhs) = default

Copy constructor/assignment operator.

ConstBitset(Bitset<Device> const &rhs)

ConstBitset &operator=(Bitset<Device> const &rhs)

Host/Device: Copy/assign a Bitset to a ConstBitset.

unsigned size() const

Host/Device: return the number of bits.

unsigned count() const

Host/Device: return the number of bits which are set to 1.

bool test(unsigned i) const

Host/Device: Return true if and only if the i‘th bit set to 1.

Non-Member Functions

template<typename DstDevice, typename SrcDevice>
void deep_copy(Bitset<DstDevice> &dst, Bitset<SrcDevice> const &src)

Copy a Bitset from src on SrcDevice to dst on DstDevice.

template<typename DstDevice, typename SrcDevice>
void deep_copy(Bitset<DstDevice> &dst, ConstBitset<SrcDevice> const &src)

Copy a ConstBitset from src on SrcDevice to a Bitset dst on DstDevice.