Matrix Transposition indexing in DArray in CUDA #543
Description
I was following along the https://github.com/jpsamaroo/DaggerWorkshop2024 and noticed that matrix transposition does not seem to work on NVIDIA GPUs for me.
Sorry if this is a bit brief, ask questions if there is something missing.
julia> scope
UnionScope:
ExactScope: processor == CuArrayDeviceProc(worker 1, device 0, uuid b8c8a4da-6ec1-2a9e-fda1-1e5e12ba47f1)
Dagger.with_options(;scope) do
# Allocated directly on the GPU
DA = rand(AutoBlocks(), Float32, 64, 64)
# Broadcast is GPU-compatible
DB = DA .* 3f0
# Matmul is no problem!
DC = DB * DB'
# Finally, any map-reduce algorithm is easy enough
# sum(DC; dims=1)
end
The error is
ERROR: DTaskFailedException:
Root Exception Type: ErrorException
Root Exception:
Scalar indexing is disallowed.
Invocation of getindex resulted in scalar indexing of a GPU array.
This is typically caused by calling an iterating implementation of a method.
Such implementations *do not* execute on the GPU, but very slowly on the CPU,
and therefore should be avoided.
If you want to allow scalar iteration, use `allowscalar` or `@allowscalar`
to enable scalar iteration globally or for the operations in question.
Stacktrace:
Julia Version 1.11.0-rc1
Commit 3a35aec36d1 (2024-06-25 10:23 UTC)
Build Info:
Official https://julialang.org/ release
Platform Info:
OS: Linux (x86_64-linux-gnu)
CPU: 20 × Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz
WORD_SIZE: 64
LLVM: libLLVM-16.0.6 (ORCJIT, skylake)
Threads: 20 default, 0 interactive, 10 GC (on 20 virtual cores)
Environment:
JULIA_DEBUG =
⌃ [052768ef] CUDA v5.4.2
[d58978e5] Dagger v0.18.12 `https://github.com/JuliaParallel/Dagger.jl.git#jps/workshop-2024`
[68e73e28] DaggerGPU v0.2.0 `https://github.com/JuliaGPU/DaggerGPU.jl.git#master`
PS: Thanks for the talk and enjoy the conference @jpsamaroo