Improve bounds checks in heap operations #954
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looks good from a quick glance, though i would like to look again more carefully. |
| rev = Base.ReverseOrdering(ord) | ||
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| buffer = heapify(arr[1:n], rev) | ||
| buffer = heapify!(arr[1:n], rev) |
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This is safe since that slice is a copy. Good catch
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| for i = n + 1 : length(arr) | ||
| @inbounds xi = arr[i] | ||
| @inbounds for i = n + 1 : length(arr) |
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Isn't this wrong? Since we do not know how arr is going to be indexed?
Or do we know?
If so it was wrong before, but it is still wrong now.
If we want this i think we need a Base.require_one_based_indexing(arr) ?
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Thanks for reviewing this! I was sprinkling Base.require_one_based_indexing around, but then I realized that any array with non-standard indexing would not be compatible with:
# Binary heap indexing
heapleft(i::Integer) = 2i
heapright(i::Integer) = 2i + 1
heapparent(i::Integer) = div(i, 2)So I wonder if the entire arrays-as-heaps.jl system should be documented as only compatible with one-based indexing and all these checks dropped. What do you think?
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I would keep the checks, and optionally document it.
the checks are more important than docs.
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