What does sizeof return for wrappers of arrays?

General Usage
1

Eg:

julia> a = ones(10);

julia> sizeof(a)
80

julia> sizeof(a')
8

julia> a = ones(ComplexF64, 10);

julia> sizeof(a')
8

I’m not sure how to interpret the results for the adjoint? Similar issues arise for OffsetArrays and other wrappers. It appears that SubArrays have the method defined:

julia> a = ones(10);

julia> sizeof(@view a[:])
80

Is this a case of missing methods for other wrappers?

2

Hunh, here I was actually surprised at the SubArray result! We don’t really have the surrounding architecture to meaningfully use sizeof’s results, and it probably doesn’t mean what you’re actually trying to understand. I’d guess you actually want something more akin to Base.summarysize instead.

You’re right, though, we should probably implement sizeof for those wrappers to just defer to their wrapped array (or just generally do better here). Thanks for bringing this up! See: #36714 and #36715.

1 Like