add sparse rrule
#579
add sparse rrule
#579
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| function rrule(::typeof(sparse), A::Union{AbstractVector, AbstractMatrix}) | ||
| function sparse_pullback(Ω̄) | ||
| return NoTangent(), Ω̄ |
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is this ok or we need to project or something?
| return sparse(I, J, V, m, n, combine), sparse_pullback | ||
| end | ||
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| function rrule(::typeof(sparse), A::Union{AbstractVector, AbstractMatrix}) |
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Should these rules be attached to sparse or one step later to things like Type{<:SparseMatrixCSC}? I don't have examples but catching all as many paths like T(A) and convert(T, A) etc. as possible sounds desirable.
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We may also need rules for SparseMatrixCSC, but for sure we need a rule for sparse since it calls sparse! for the heavy-duty.
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Yes, I meant for the 1-arg sparse. The one which takes all the vectors is a different story.
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Ah sorry, didn't notice what you were pointing at. I'm not super confident in defining rrules for constructors.
Should it be rrule(::Type{<:SparseMatrixCSC},...) or rrule(::Type{<:SparseMatrixCSC{Tv,Ti},...) or the two are equivalent?
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I fiddle until it works, but my guess is that the first would capture all mode specific cases. Maybe not convert though.
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ok I defined the rrules for the type and removed this one. I did check separately that Zygote's gradients of sparse(A) and sparse(v) go through
Partial replacement for #246
cc @sethaxen