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Mojo function
ncclCommInitAll
def ncclCommInitAll(comms: Pointer[Optional[Pointer[NoneType, MutUntrackedOrigin]]], ndev: Int, devlist: Pointer[Int32]) -> ncclResult_t
Initializes NCCL/RCCL communicators for a set of GPUs.
Thin FFI wrapper around ncclCommInitAll. Allocates one communicator per
device in devlist and stores the handles in comms. Must be called from
a single thread; concurrent calls for the same device set cause undefined
behavior in the NCCL library.
Args:
- comms (
Pointer[Optional[Pointer[NoneType, MutUntrackedOrigin]]]): Output array of communicator handles; must have room forndeventries. - ndev (
Int): Number of GPUs to include in the communicator group. - devlist (
Pointer[Int32]): Array of CUDA/ROCm device IDs to include.
Returns:
ncclResult_t: ncclResult_t.ncclSuccess on success; a non-zero status on failure.
Raises:
If the CCL function symbol cannot be resolved from the vendor library.