workItemFunctions(3) Manual Page

uint get_work_dim()

Returns the number of dimensions in use. This is the value given to the work_dim argument specified in clEnqueueNDRangeKernel.

size_t get_global_size(uint dimindx)

Returns the number of global work-items specified for dimension identified by dimindx. This value is given by the global_work_size argument to clEnqueueNDRangeKernel.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_global_size() returns 1.

size_t get_global_id(uint dimindx)

Returns the unique global work-item ID value for dimension identified by dimindx. The global work-item ID specifies the work-item ID based on the number of global work-items specified to execute the kernel.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_global_id() returns 0.

size_t get_local_size(uint dimindx)

Returns the number of local work-items specified in dimension identified by dimindx. This value is at most the value given by the local_work_size argument to clEnqueueNDRangeKernel if local_work_size is not NULL; otherwise the OpenCL implementation chooses an appropriate local_work_size value which is returned by this function. If the kernel is executed with a non-uniform work-group size ^[1], calls to this built-in from some work-groups may return different values than calls to this built-in from other work-groups.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_local_size() returns 1.

size_t get_enqueued_local_size( uint dimindx)

Returns the same value as that returned by get_local_size(dimindx) if the kernel is executed with a uniform work-group size.

If the kernel is executed with a non-uniform work-group size, returns the number of local work-items in each of the work-groups that make up the uniform region of the global range in the dimension identified by dimindx. If the local_work_size argument to clEnqueueNDRangeKernel is not NULL, this value will match the value specified in local_work_size[dimindx]. If local_work_size is NULL, this value will match the local size that the implementation determined would be most efficient at implementing the uniform region of the global range.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_enqueued_local_size() returns 1.

Requires support for OpenCL 2.0 or newer.

size_t get_local_id(uint dimindx)

Returns the unique local work-item ID, i.e. a work-item within a specific work-group for dimension identified by dimindx.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_local_id() returns 0.

size_t get_num_groups(uint dimindx)

Returns the number of work-groups that will execute a kernel for dimension identified by dimindx.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values of dimindx, get_num_groups() returns 1.

size_t get_group_id(uint dimindx)

get_group_id returns the work-group ID which is a number from 0 .. get_num_groups(dimindx) - 1.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values, get_group_id() returns 0.

size_t get_global_offset(uint dimindx)

get_global_offset returns the offset values specified in global_work_offset argument to clEnqueueNDRangeKernel.

Valid values of dimindx are 0 to get_work_dim() - 1. For other values, get_global_offset() returns 0.

Requires support for OpenCL C 1.1 or newer.

size_t get_global_linear_id()

Returns the work-items 1-dimensional global ID.

For 1D work-groups, it is computed as get_global_id(0) - get_global_offset(0).

For 2D work-groups, it is computed as (get_global_id(1) - get_global_offset(1)) * get_global_size(0) + (get_global_id(0) - get_global_offset(0)).

For 3D work-groups, it is computed as ((get_global_id(2) - get_global_offset(2)) * get_global_size(1) * get_global_size(0)) + ((get_global_id(1) - get_global_offset(1)) * get_global_size(0)) + (get_global_id(0) - get_global_offset(0)).

Requires support for OpenCL 2.0 or newer.

size_t get_local_linear_id()

Returns the work-items 1-dimensional local ID.

For 1D work-groups, it is the same value as

get_local_id(0).

For 2D work-groups, it is computed as

get_local_id(1) * get_local_size(0) + get_local_id(0).

For 3D work-groups, it is computed as

(get_local_id(2) * get_local_size(1) * get_local_size(0)) + (get_local_id(1) * get_local_size(0)) + get_local_id(0).

Requires support for OpenCL 2.0 or newer.

Returns the number of work-items in the sub-group. This value is no more than the maximum sub-group size and is implementation-defined based on a combination of the compiled kernel and the dispatch dimensions. This will be a constant value for the lifetime of the sub-group.

Returns the maximum size of a sub-group within the dispatch. This value will be invariant for a given set of dispatch dimensions and a kernel object compiled for a given device.

Returns the number of sub-groups that the current work-group is divided into.

This number will be constant for the duration of a work-group’s execution. If the kernel is executed with a non-uniform work-group size (i.e. the global_work_size values specified to clEnqueueNDRangeKernel are not evenly divisible by the local_work_size values for any dimension, calls to this built-in from some work-groups may return different values than calls to this built-in from other work-groups.

Returns the same value as that returned by get_num_sub_groups if the kernel is executed with a uniform work-group size.

If the kernel is executed with a non-uniform work-group size, returns the number of sub-groups in each of the work-groups that make up the uniform region of the global range.

get_sub_group_id returns the sub-group ID which is a number from 0 .. get_num_sub_groups() - 1.

For clEnqueueTask, this returns 0.

Returns the unique work-item ID within the current sub-group. The mapping from get_local_id(dimindx) to get_sub_group_local_id will be invariant for the lifetime of the work-group.