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speed up logical indexing by bitarray #29746

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Oct 24, 2018
Merged

speed up logical indexing by bitarray #29746

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17fd485
speed up logical indexing by bitarray
chethega Oct 20, 2018
ada8bc8
changed inbounds / OOB behavior to match array iterators
chethega Oct 22, 2018
1328295
Update base/multidimensional.jl
mbauman Oct 24, 2018
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1 change: 1 addition & 0 deletions base/bitarray.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,7 @@ IndexStyle(::Type{<:BitArray}) = IndexLinear()
const _msk64 = ~UInt64(0)
@inline _div64(l) = l >> 6
@inline _mod64(l) = l & 63
@inline _blsr(x)= x & (x-1) #zeros the last set bit. Has native instruction on many archs. needed in multidimensional.jl
@inline _msk_end(l::Integer) = _msk64 >>> _mod64(-l)
@inline _msk_end(B::BitArray) = _msk_end(length(B))
num_bit_chunks(n::Int) = _div64(n+63)
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26 changes: 15 additions & 11 deletions base/multidimensional.jl
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Expand Up @@ -523,19 +523,23 @@ end
L.mask[idx] && return (idx, s)
end
end
# When wrapping a BitArray, lean heavily upon its internals -- this is a common
# case. Just use the Int index and count as its state.
@inline function iterate(L::LogicalIndex{Int,<:BitArray}, s=(0,1))
s[2] > length(L) && return nothing
i, n = s
# When wrapping a BitArray, lean heavily upon its internals.
@inline function iterate(L::Base.LogicalIndex{Int,<:BitArray})
L.sum == 0 && return nothing
Bc = L.mask.chunks
while true
if Bc[_div64(i)+1] & (UInt64(1)<<_mod64(i)) != 0
i += 1
return (i, (i, n+1))
end
i += 1
return iterate(L, (1, @inbounds Bc[1]))
end
@inline function iterate(L::Base.LogicalIndex{Int,<:BitArray}, s)
Bc = L.mask.chunks
i1, c = s
while c==0
i1 % UInt >= length(Bc) % UInt && return nothing
i1 += 1
@inbounds c = Bc[i1]
end
tz = trailing_zeros(c) + 1
c = _blsr(c)
return ((i1-1)<<6 + tz, (i1, c))
end

@inline checkbounds(::Type{Bool}, A::AbstractArray, I::LogicalIndex{<:Any,<:AbstractArray{Bool,1}}) =
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