PrefixScan
The PrefixScan class provides an efficient implementation of the prefix scan (sum) algorithm, supporting both single and multiple array scanning. It is highly configurable and optimized for parallel computing, commonly used in tasks such as data aggregation and parallel processing. The class supports various modes and flags, allowing for flexible control over the scanning process, including the ability to perform indirect scans using dispatch buffers. Its methods enable in-place scanning for both single and multiple datasets, with support for large-scale data processing across multiple regions.
#include <parallel/TellusimPrefixScan.h>
Constructors
PrefixScan()
Methods
Clear scan.
void clear()
Check scan.
bool isCreated(Flags flags) const
Scan parameters.
uint32_t getGroupSize() const
uint32_t getScanElements() const
uint32_t getMaxElements() const
uint32_t getMaxRegions() const
Create prefix scan.
bool create(const Device &device, Mode mode, uint32_t groups = 256, uint32_t regions = 1, Async *async = nullptr)
bool create(const Device &device, Flags flags, uint32_t groups = 256, uint32_t regions = 1, Async *async = nullptr)
| Type | Name | Description |
|---|---|---|
| uint32_t | groups | Prefix scan group size. |
| uint32_t | regions | Maximum number of multiple regions. |
Dispatch single in-place prefix scan.
bool dispatch(Compute &compute, Buffer &data, uint32_t offset, uint32_t size)
| Type | Name | Description |
|---|---|---|
| Buffer | data | Buffer of uint32_t elements to scan. |
| uint32_t | offset | Elements offset index (4 aligned). |
| uint32_t | size | Number of uint32_t elements to scan. |
Dispatch multiple in-place prefix scans.
bool dispatch(Compute &compute, Buffer &data, uint32_t count, const uint32_t *offsets, const uint32_t *sizes, Flags flags = FlagNone)
| Type | Name | Description |
|---|---|---|
| Buffer | data | Buffer of uint32_t elements to scan. |
| uint32_t | count | Number of regions to scan. |
| uint32_t | offsets | Elements offset index (4 aligned). |
| uint32_t | sizes | Number of uint32_t elements to scan. |
Dispatch single in-place indirect prefix scan.
bool dispatchIndirect(Compute &compute, Buffer &data, Buffer &dispatch, uint32_t offset, Flags flags = FlagNone, uint32_t max_size = Maxu32)
| Type | Name | Description |
|---|---|---|
| Buffer | data | Buffer of uint32_t elements to scan. |
| Buffer | dispatch | Dispatch indirect buffer. |
| uint32_t | offset | Dispatch indirect buffer offset. |
| uint32_t | max_size | Maximum number of elements to scan. |
Dispatch multiple in-place indirect prefix scans.
bool dispatchIndirect(Compute &compute, Buffer &data, uint32_t count, Buffer &dispatch, uint32_t offset, Flags flags = FlagNone, uint32_t max_size = Maxu32)
| Type | Name | Description |
|---|---|---|
| Buffer | data | Buffer of uint32_t elements to scan. |
| uint32_t | count | Number of regions to scan. |
| Buffer | dispatch | Dispatch indirect buffer. |
| uint32_t | offset | Dispatch indirect buffer offset. |
| uint32_t | max_size | Maximum number of elements to scan. |
Dispatch multiple in-place indirect prefix scans.
bool dispatchIndirect(Compute &compute, Buffer &data, Buffer &count, Buffer &dispatch, uint32_t count_offset, uint32_t dispatch_offset, Flags flags = FlagNone, uint32_t max_size = Maxu32)
| Type | Name | Description |
|---|---|---|
| Buffer | data | Buffer of uint32_t elements to scan. |
| Buffer | count | Count indirect buffer. |
| Buffer | dispatch | Dispatch indirect buffer. |
| uint32_t | count_offset | Count indirect buffer offset. |
| uint32_t | dispatch_offset | Dispatch indirect buffer offset. |
| uint32_t | max_size | Maximum number of elements to scan. |
Enums
Mode
Scan modes.
| Name | Value | Description |
|---|---|---|
| ModeSingle | 0 | Single array scan. |
| ModeMultiple | 1 | Multiple arrays scan. |
| NumModes | 2 |
Flags
Scan flags.
| Name | Value | Description |
|---|---|---|
| FlagNone | 0 | |
| FlagSingle | (1 << ModeSingle) | Enable Single array prefix mode. |
| FlagMultiple | (1 << ModeMultiple) | Enable Multi array prefix mode. |
| FlagIndirect | (1 << (NumModes + 0)) | Enable Dispatch Indirect mode. |
| FlagRepeat | (1 << (NumModes + 1)) | Repeat Dispatch Indirect prefix scan with the same parameters. |
| FlagsAll | (FlagSingle | FlagMultiple | FlagIndirect) |
Structs
DispatchParameters
.
Variables
| Type | Name | Description |
|---|---|---|
| uint32_t | offset | Elements offset index (4 aligned). |
| uint32_t | size | Number of elements to scan. |
| uint32_t | padding_0 | |
| uint32_t | padding_1 |