argmax returns incorrect results

[yurivish]

This package incorrectly implements argmax for ChainedVectors. It returns the maximum value, rather than its index.

julia> using SentinelArrays

julia> arrays = [
         [18, 70, 92, 15, 65],
         [25, 14, 95, 54, 57]
       ];

julia> cv = ChainedVector(arrays);

julia> argmax(cv)
95

julia> argmax(collect(cv))
8

The implementation is here and is tested, though the test only tests a simple special case for which the values and indices are exactly equal.

This issue was initially reported upstream.

[Moelf]

huh....

julia> using SentinelArrays
Precompiling SentinelArrays
  1 dependency successfully precompiled in 2 seconds

julia> x2 = ChainedVector([[2,1,3], [4,5,6], [7,8,10,9]])
10-element ChainedVector{Int64, Vector{Int64}}:
  2
  1
  3
  4
  5
  6
  7
  8
 10
  9

julia> findmin(x2)
(1, 1)

julia> findmin(x2 |> collect)
(1, 2)

is this just completely wrong? even the findmin seems to be wrong.

[quinnj]

PRs welcome!

[Moelf]

I will try tmr but this is a pretty critical problem that also runs somewhat deep, you sure you trust first timer PR?