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Table Comparing Syntax for Different Compute APIs

Contents

Table Comparing Syntax for Different Compute APIs#

Term	CUDA	HIP	OpenCL
Device	`int deviceId`	`int deviceId`	`cl_device`
Queue	`cudaStream_t`	`hipStream_t`	`cl_command_queue`
Event	`cudaEvent_t`	`hipEvent_t`	`cl_event`
Memory	`void *`	`void *`	`cl_mem`

	grid	grid	NDRange
	block	block	work-group
	thread	thread	work-item
	warp	warp	sub-group

Thread- index	`threadIdx.x`	`threadIdx.x`	`get_local_id(0)`
Block- index	`blockIdx.x`	`blockIdx.x`	`get_group_id(0)`
Block- dim	`blockDim.x`	`blockDim.x`	`get_local_size(0)`
Grid-dim	`gridDim.x`	`gridDim.x`	`get_num_groups(0)`

Device Kernel	`__global__`	`__global__`	`__kernel`
Device Function	`__device__`	`__device__`	Implied in device compilation
Host Function	`__host_` (default)	`__host_` (default)	Implied in host compilation
Host + Device Function	`__host__` `__device__`	`__host__` `__device__`	No equivalent
Kernel Launch	`<<< >>>`	`hipLaunchKernel`/`hipLaunchKernelGGL`/`<<< >>>`	`clEnqueueNDRangeKernel`

Global Memory	`__global__`	`__global__`	`__global`
Group Memory	`__shared__`	`__shared__`	`__local`
Constant	`__constant__`	`__constant__`	`__constant`

	`__syncthreads`	`__syncthreads`	`barrier(CLK_LOCAL_MEMFENCE)`
Atomic Builtins	`atomicAdd`	`atomicAdd`	`atomic_add`
Precise Math	`cos(f)`	`cos(f)`	`cos(f)`
Fast Math	`__cos(f)`	`__cos(f)`	`native_cos(f)`
Vector	`float4`	`float4`	`float4`

Notes#

The indexing functions (starting with thread-index) show the terminology for a 1D grid. Some APIs use reverse order of xyz / 012 indexing for 3D grids.