ANN: UnsafeArray.jl


Dear all,

I’d like to present UnsafeArray.jl. It’s main function is to provide (heap-)allocation-free array views. It provides a (hopefully) safe alternative to ArrayViews.UnsafeArrayView, and integrates with Base.view() and Base.SubArray.


@uviews A B C ... begin
    # Within this scope, arrays A B C ... are replaced by stack-allocated (pointer-based)
    # bitstype UnsafeArrays, view()'s on these are also bitstypes and stack-allocated.
    # The original arrays are protected from GC, but it's the user's responsibility not to
    # let the unsafe version of A B C ... escape from this scope.

I did some initial benchmarking, the results are quite encouraging.


Could you compare your design goals with the design goals of StaticArrays.jl?


StaticArrays are statically sized, allowing very heavy specialisations and optimizations for a specific shape. Since some subtypes are also immutable, the whole array can be stack allocated.

The above Package offers stack allocated views into normal heap allocated julia arrays :wink: So the array itself is not immutable and doesn’t hold its size as a static type parameter.


StaticArrays (please correct me if I’m wrong) is something very different, it provides stack-allocated arrays of fixed/hard-coded size. UnsafeArrays provides stack-allocated views (of arbitrary size) of heap-allocated arrays.


Darn, you were faster, Simon. :wink: