https://github.com/JuliaLang/julia
Revision 57bd56e87a644b42a30bf3aa3cc9d59836dfdad6 authored by Takafumi Arakaki on 25 December 2021, 08:56:07 UTC, committed by GitHub on 25 December 2021, 08:56:07 UTC
1 parent 0064663
Tip revision: 57bd56e87a644b42a30bf3aa3cc9d59836dfdad6 authored by Takafumi Arakaki on 25 December 2021, 08:56:07 UTC
Fix a markdown link syntax error (#43543)
Fix a markdown link syntax error (#43543)
Tip revision: 57bd56e
arraymath.jl
# This file is a part of Julia. License is MIT: https://julialang.org/license
## Binary arithmetic operators ##
for f in (:+, :-)
@eval function ($f)(A::AbstractArray, B::AbstractArray)
promote_shape(A, B) # check size compatibility
broadcast_preserving_zero_d($f, A, B)
end
end
function +(A::Array, Bs::Array...)
for B in Bs
promote_shape(A, B) # check size compatibility
end
broadcast_preserving_zero_d(+, A, Bs...)
end
for f in (:/, :\, :*)
if f !== :/
@eval ($f)(A::Number, B::AbstractArray) = broadcast_preserving_zero_d($f, A, B)
end
if f !== :\
@eval ($f)(A::AbstractArray, B::Number) = broadcast_preserving_zero_d($f, A, B)
end
end
## data movement ##
"""
reverse(A; dims=:)
Reverse `A` along dimension `dims`, which can be an integer (a
single dimension), a tuple of integers (a tuple of dimensions)
or `:` (reverse along all the dimensions, the default). See
also [`reverse!`](@ref) for in-place reversal.
# Examples
```jldoctest
julia> b = Int64[1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> reverse(b, dims=2)
2×2 Matrix{Int64}:
2 1
4 3
julia> reverse(b)
2×2 Matrix{Int64}:
4 3
2 1
```
!!! compat "Julia 1.6"
Prior to Julia 1.6, only single-integer `dims` are supported in `reverse`.
"""
reverse(A::AbstractArray; dims=:) = _reverse(A, dims)
_reverse(A, dims) = reverse!(copymutable(A); dims)
"""
reverse!(A; dims=:)
Like [`reverse`](@ref), but operates in-place in `A`.
!!! compat "Julia 1.6"
Multidimensional `reverse!` requires Julia 1.6.
"""
reverse!(A::AbstractArray; dims=:) = _reverse!(A, dims)
_reverse!(A::AbstractArray{<:Any,N}, ::Colon) where {N} = _reverse!(A, ntuple(identity, Val{N}()))
_reverse!(A, dim::Integer) = _reverse!(A, (Int(dim),))
_reverse!(A, dims::NTuple{M,Integer}) where {M} = _reverse!(A, Int.(dims))
function _reverse!(A::AbstractArray{<:Any,N}, dims::NTuple{M,Int}) where {N,M}
dimrev = ntuple(k -> k in dims, Val{N}()) # boolean tuple indicating reversed dims
if N < M || M != sum(dimrev)
throw(ArgumentError("invalid dimensions $dims in reverse!"))
end
M == 0 && return A # nothing to reverse
# swapping loop only needs to traverse ≈half of the array
halfsz = ntuple(k -> k == dims[1] ? size(A,k) ÷ 2 : size(A,k), Val{N}())
last1 = ntuple(k -> lastindex(A,k)+firstindex(A,k), Val{N}()) # offset for reversed index
for i in CartesianIndices(ntuple(k -> firstindex(A,k):firstindex(A,k)-1+@inbounds(halfsz[k]), Val{N}()))
iₜ = Tuple(i)
iᵣ = CartesianIndex(ifelse.(dimrev, last1 .- iₜ, iₜ))
@inbounds A[iᵣ], A[i] = A[i], A[iᵣ]
end
if M > 1 && isodd(size(A, dims[1]))
# middle slice for odd dimensions must be recursively flipped
mid = firstindex(A, dims[1]) + (size(A, dims[1]) ÷ 2)
midslice = CartesianIndices(ntuple(k -> k == dims[1] ? (mid:mid) : (firstindex(A,k):lastindex(A,k)), Val{N}()))
_reverse!(view(A, midslice), dims[2:end])
end
return A
end
# fix ambiguity with array.jl:
_reverse!(A::AbstractVector, dim::Tuple{Int}) = _reverse!(A, first(dim))
"""
rotl90(A)
Rotate matrix `A` left 90 degrees.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rotl90(a)
2×2 Matrix{Int64}:
2 4
1 3
```
"""
function rotl90(A::AbstractMatrix)
ind1, ind2 = axes(A)
B = similar(A, (ind2,ind1))
n = first(ind2)+last(ind2)
for i=axes(A,1), j=ind2
B[n-j,i] = A[i,j]
end
return B
end
"""
rotr90(A)
Rotate matrix `A` right 90 degrees.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rotr90(a)
2×2 Matrix{Int64}:
3 1
4 2
```
"""
function rotr90(A::AbstractMatrix)
ind1, ind2 = axes(A)
B = similar(A, (ind2,ind1))
m = first(ind1)+last(ind1)
for i=ind1, j=axes(A,2)
B[j,m-i] = A[i,j]
end
return B
end
"""
rot180(A)
Rotate matrix `A` 180 degrees.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rot180(a)
2×2 Matrix{Int64}:
4 3
2 1
```
"""
function rot180(A::AbstractMatrix)
B = similar(A)
ind1, ind2 = axes(A,1), axes(A,2)
m, n = first(ind1)+last(ind1), first(ind2)+last(ind2)
for j=ind2, i=ind1
B[m-i,n-j] = A[i,j]
end
return B
end
"""
rotl90(A, k)
Left-rotate matrix `A` 90 degrees counterclockwise an integer `k` number of times.
If `k` is a multiple of four (including zero), this is equivalent to a `copy`.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rotl90(a,1)
2×2 Matrix{Int64}:
2 4
1 3
julia> rotl90(a,2)
2×2 Matrix{Int64}:
4 3
2 1
julia> rotl90(a,3)
2×2 Matrix{Int64}:
3 1
4 2
julia> rotl90(a,4)
2×2 Matrix{Int64}:
1 2
3 4
```
"""
function rotl90(A::AbstractMatrix, k::Integer)
k = mod(k, 4)
k == 1 ? rotl90(A) :
k == 2 ? rot180(A) :
k == 3 ? rotr90(A) : copy(A)
end
"""
rotr90(A, k)
Right-rotate matrix `A` 90 degrees clockwise an integer `k` number of times.
If `k` is a multiple of four (including zero), this is equivalent to a `copy`.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rotr90(a,1)
2×2 Matrix{Int64}:
3 1
4 2
julia> rotr90(a,2)
2×2 Matrix{Int64}:
4 3
2 1
julia> rotr90(a,3)
2×2 Matrix{Int64}:
2 4
1 3
julia> rotr90(a,4)
2×2 Matrix{Int64}:
1 2
3 4
```
"""
rotr90(A::AbstractMatrix, k::Integer) = rotl90(A,-k)
"""
rot180(A, k)
Rotate matrix `A` 180 degrees an integer `k` number of times.
If `k` is even, this is equivalent to a `copy`.
# Examples
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> rot180(a,1)
2×2 Matrix{Int64}:
4 3
2 1
julia> rot180(a,2)
2×2 Matrix{Int64}:
1 2
3 4
```
"""
rot180(A::AbstractMatrix, k::Integer) = mod(k, 2) == 1 ? rot180(A) : copy(A)
Computing file changes ...