forked from JuliaLang/julia
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathslicearray.jl
244 lines (191 loc) · 7.23 KB
/
slicearray.jl
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
"""
AbstractSlices{S,N} <: AbstractArray{S,N}
Supertype for arrays of slices into a parent array over some dimension(s),
returning views that select all the data from the other dimensions.
`parent` will return the parent array.
"""
abstract type AbstractSlices{T,N} <: AbstractArray{T,N} end
"""
Slices{P,SM,AX,S,N} <: AbstractSlices{S,N}
An `AbstractArray` of slices into a parent array over specified dimension(s),
returning views that select all the data from the other dimension(s).
These should typically be constructed by [`eachslice`](@ref), [`eachcol`](@ref) or
[`eachrow`](@ref).
[`parent(s::Slices)`](@ref) will return the parent array.
"""
struct Slices{P,SM,AX,S,N} <: AbstractSlices{S,N}
"""
Parent array
"""
parent::P
"""
A tuple of length `ndims(parent)`, denoting how each dimension should be handled:
- an integer `i`: this is the `i`th dimension of the outer `Slices` object.
- `:`: an "inner" dimension
"""
slicemap::SM
"""
A tuple of length `N` containing the [`axes`](@ref) of the `Slices` object.
"""
axes::AX
end
unitaxis(::AbstractArray) = Base.OneTo(1)
function Slices(A::P, slicemap::SM, ax::AX) where {P,SM,AX}
N = length(ax)
S = Base._return_type(view, Tuple{P, map((a,l) -> l === (:) ? Colon : eltype(a), axes(A), slicemap)...})
Slices{P,SM,AX,S,N}(A, slicemap, ax)
end
_slice_check_dims(N) = nothing
function _slice_check_dims(N, dim, dims...)
1 <= dim <= N || throw(DimensionMismatch("Invalid dimension $dim"))
dim in dims && throw(DimensionMismatch("Dimensions $dims are not unique"))
_slice_check_dims(N,dims...)
end
@constprop :aggressive function _eachslice(A::AbstractArray{T,N}, dims::NTuple{M,Integer}, drop::Bool) where {T,N,M}
_slice_check_dims(N,dims...)
if drop
# if N = 4, dims = (3,1) then
# axes = (axes(A,3), axes(A,1))
# slicemap = (2, :, 1, :)
ax = map(dim -> axes(A,dim), dims)
slicemap = ntuple(dim -> something(findfirst(isequal(dim), dims), (:)), N)
return Slices(A, slicemap, ax)
else
# if N = 4, dims = (3,1) then
# axes = (axes(A,1), OneTo(1), axes(A,3), OneTo(1))
# slicemap = (1, :, 3, :)
ax = ntuple(dim -> dim in dims ? axes(A,dim) : unitaxis(A), N)
slicemap = ntuple(dim -> dim in dims ? dim : (:), N)
return Slices(A, slicemap, ax)
end
end
@inline function _eachslice(A::AbstractArray, dim::Integer, drop::Bool)
_eachslice(A, (dim,), drop)
end
"""
eachslice(A::AbstractArray; dims, drop=true)
Create a [`Slices`](@ref) object that is an array of slices over dimensions `dims` of `A`, returning
views that select all the data from the other dimensions in `A`. `dims` can either by an
integer or a tuple of integers.
If `drop = true` (the default), the outer `Slices` will drop the inner dimensions, and
the ordering of the dimensions will match those in `dims`. If `drop = false`, then the
`Slices` will have the same dimensionality as the underlying array, with inner
dimensions having size 1.
See [`stack`](@ref)`(slices; dims)` for the inverse of `eachslice(A; dims::Integer)`.
See also [`eachrow`](@ref), [`eachcol`](@ref), [`mapslices`](@ref) and [`selectdim`](@ref).
!!! compat "Julia 1.1"
This function requires at least Julia 1.1.
!!! compat "Julia 1.9"
Prior to Julia 1.9, this returned an iterator, and only a single dimension `dims` was supported.
# Example
```jldoctest
julia> m = [1 2 3; 4 5 6; 7 8 9]
3×3 Matrix{Int64}:
1 2 3
4 5 6
7 8 9
julia> s = eachslice(m, dims=1)
3-element RowSlices{Matrix{Int64}, Tuple{Base.OneTo{Int64}}, SubArray{Int64, 1, Matrix{Int64}, Tuple{Int64, Base.Slice{Base.OneTo{Int64}}}, true}}:
[1, 2, 3]
[4, 5, 6]
[7, 8, 9]
julia> s[1]
3-element view(::Matrix{Int64}, 1, :) with eltype Int64:
1
2
3
julia> eachslice(m, dims=1, drop=false)
3×1 Slices{Matrix{Int64}, Tuple{Int64, Colon}, Tuple{Base.OneTo{Int64}, Base.OneTo{Int64}}, SubArray{Int64, 1, Matrix{Int64}, Tuple{Int64, Base.Slice{Base.OneTo{Int64}}}, true}, 2}:
[1, 2, 3]
[4, 5, 6]
[7, 8, 9]
```
"""
@inline function eachslice(A; dims, drop=true)
_eachslice(A, dims, drop)
end
"""
eachrow(A::AbstractVecOrMat) <: AbstractVector
Create a [`RowSlices`](@ref) object that is a vector of rows of matrix or vector `A`.
Row slices are returned as `AbstractVector` views of `A`.
For the inverse, see [`stack`](@ref)`(rows; dims=1)`.
See also [`eachcol`](@ref), [`eachslice`](@ref) and [`mapslices`](@ref).
!!! compat "Julia 1.1"
This function requires at least Julia 1.1.
!!! compat "Julia 1.9"
Prior to Julia 1.9, this returned an iterator.
# Example
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> s = eachrow(a)
2-element RowSlices{Matrix{Int64}, Tuple{Base.OneTo{Int64}}, SubArray{Int64, 1, Matrix{Int64}, Tuple{Int64, Base.Slice{Base.OneTo{Int64}}}, true}}:
[1, 2]
[3, 4]
julia> s[1]
2-element view(::Matrix{Int64}, 1, :) with eltype Int64:
1
2
```
"""
eachrow(A::AbstractMatrix) = _eachslice(A, (1,), true)
eachrow(A::AbstractVector) = eachrow(reshape(A, size(A,1), 1))
"""
eachcol(A::AbstractVecOrMat) <: AbstractVector
Create a [`ColumnSlices`](@ref) object that is a vector of columns of matrix or vector `A`.
Column slices are returned as `AbstractVector` views of `A`.
For the inverse, see [`stack`](@ref)`(cols)` or `reduce(`[`hcat`](@ref)`, cols)`.
See also [`eachrow`](@ref), [`eachslice`](@ref) and [`mapslices`](@ref).
!!! compat "Julia 1.1"
This function requires at least Julia 1.1.
!!! compat "Julia 1.9"
Prior to Julia 1.9, this returned an iterator.
# Example
```jldoctest
julia> a = [1 2; 3 4]
2×2 Matrix{Int64}:
1 2
3 4
julia> s = eachcol(a)
2-element ColumnSlices{Matrix{Int64}, Tuple{Base.OneTo{Int64}}, SubArray{Int64, 1, Matrix{Int64}, Tuple{Base.Slice{Base.OneTo{Int64}}, Int64}, true}}:
[1, 3]
[2, 4]
julia> s[1]
2-element view(::Matrix{Int64}, :, 1) with eltype Int64:
1
3
```
"""
eachcol(A::AbstractMatrix) = _eachslice(A, (2,), true)
eachcol(A::AbstractVector) = eachcol(reshape(A, size(A, 1), 1))
"""
RowSlices{M,AX,S}
A special case of [`Slices`](@ref) that is a vector of row slices of a matrix, as
constructed by [`eachrow`](@ref).
[`parent`](@ref) can be used to get the underlying matrix.
"""
const RowSlices{P<:AbstractMatrix,AX,S<:AbstractVector} = Slices{P,Tuple{Int,Colon},AX,S,1}
"""
ColumnSlices{M,AX,S}
A special case of [`Slices`](@ref) that is a vector of column slices of a matrix, as
constructed by [`eachcol`](@ref).
[`parent`](@ref) can be used to get the underlying matrix.
"""
const ColumnSlices{P<:AbstractMatrix,AX,S<:AbstractVector} = Slices{P,Tuple{Colon,Int},AX,S,1}
IteratorSize(::Type{Slices{P,SM,AX,S,N}}) where {P,SM,AX,S,N} = HasShape{N}()
axes(s::Slices) = s.axes
size(s::Slices) = map(length, s.axes)
@inline function _slice_index(s::Slices, c...)
return map(l -> l === (:) ? (:) : c[l], s.slicemap)
end
@inline function getindex(s::Slices{P,SM,AX,S,N}, I::Vararg{Int,N}) where {P,SM,AX,S,N}
@boundscheck checkbounds(s, I...)
@inbounds view(s.parent, _slice_index(s, I...)...)
end
@inline function setindex!(s::Slices{P,SM,AX,S,N}, val, I::Vararg{Int,N}) where {P,SM,AX,S,N}
@boundscheck checkbounds(s, I...)
@inbounds s.parent[_slice_index(s, I...)...] = val
end
parent(s::Slices) = s.parent