normalize strides; avoids (mul!) issues with with size zero arrays

Jutho · Oct 2, 2020 · 5ab2938 · 5ab2938 · Jutho · Oct 3, 2020
1 parent 41b7952
commit 5ab2938
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Showing 3 changed files with 16 additions and 2 deletions.
diff --git a/src/abstractstridedview.jl b/src/abstractstridedview.jl
@@ -275,6 +275,19 @@ function _simplify(size::Dims{N}, strides::Dims{N}) where {N}
     end
 end
 
+_normalizestrides(size::Tuple{}, strides::Tuple{}) = strides
+function _normalizestrides(size::Dims{N}, strides::Dims{N}) where {N}
+    if size[1] <= 1 # 0 or 1
+        strides = Base.setindex(strides, 1, 1)
+    end
+    for i = 2:N
+        if size[i] <= 1 # 0 or 1
+            strides = Base.setindex(strides, strides[i-1]*max(1, size[i-1]), i)
+        end
+    end
+    return strides
+end
+
 _computereshapestrides(newsize::Tuple{}, oldsize::Tuple{}, strides::Tuple{}) = strides
 function _computereshapestrides(newsize::Tuple{}, oldsize::Dims{N}, strides::Dims{N}) where {N}
     all(isequal(1), oldsize) || throw(DimensionMismatch())

diff --git a/src/stridedview.jl b/src/stridedview.jl
@@ -14,7 +14,8 @@ function StridedView(parent::Array{S},
 
     T = Base.promote_op(op, S)
     # reshape array to vector in order to reduce number of element types
-    StridedView{T,N,Vector{S},F}(reshape(parent, length(parent)), size, strides, offset, op)
+    StridedView{T,N,Vector{S},F}(reshape(parent, length(parent)), size,
+                                    _normalizestrides(size, strides), offset, op)
 end
 function StridedView(parent::A,
                         size::NTuple{N,Int} = size(parent),

diff --git a/src/unsafestridedview.jl b/src/unsafestridedview.jl
@@ -11,7 +11,7 @@ function UnsafeStridedView(a::Ptr{PT}, size::NTuple{N,Int}, strides::NTuple{N,In
 
     @assert isbitstype(PT)
     T = Base.promote_op(op, PT)
-    UnsafeStridedView{T,N,PT,F}(a, size, strides, offset, op)
+    UnsafeStridedView{T,N,PT,F}(a, size, _normalizestrides(size, strides), offset, op)
 end
 
 UnsafeStridedView(a::Ptr{T}, size::NTuple{N,Int}, strides::NTuple{N,Int},