Find n smallest values in an n dims array

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@JeffreySarnoff that seems to do something different than how I interpreted the question.

julia> A = rand(0:128, 4, 3, 2)
4×3×2 Array{Int64, 3}:
[:, :, 1] =
 33   83    7
 41  128  107
 86    3   17
 64  115   25

[:, :, 2] =
 61   46  81
 23   75  92
 58   58  40
 24  103  20

julia> indexmins(M, n) =
              CartesianIndices(M)[
                        sort(findall(x->(x <= n),
                             sortperm(vec(M))))]
indexmins (generic function with 1 method)

julia> ind = indexmins(A, 5)
5-element Vector{CartesianIndex{3}}:
 CartesianIndex(4, 2, 1)
 CartesianIndex(2, 3, 1)
 CartesianIndex(3, 1, 2)
 CartesianIndex(2, 2, 2)
 CartesianIndex(3, 2, 2)

julia> A[ind]
5-element Vector{Int64}:
 115
 107
  58
  75
  58

I thought he wanted the indices of the 5 smallest values in the original array:

julia> function arg_n_smallest_values(A::AbstractArray{T,N}, n::Integer) where {T,N}
           perm = sortperm(vec(A))
           ci = CartesianIndices(A)
           return ci[perm[1:n]]
       end
arg_n_smallest_values (generic function with 2 methods)

julia> ind = arg_n_smallest_values(A, 5)
5-element Vector{CartesianIndex{3}}:
 CartesianIndex(3, 2, 1)
 CartesianIndex(1, 3, 1)
 CartesianIndex(3, 3, 1)
 CartesianIndex(4, 3, 2)
 CartesianIndex(2, 1, 2)

julia> A[ind]
5-element Vector{Int64}:
  3
  7
 17
 20
 23
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