From eda4131859229c7d9de4461e154a73bb89a6b783 Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Sat, 15 Feb 2020 06:20:38 -0600
Subject: [PATCH] Convert range type in `reduced_index`
The `reduced_indices` and `reduced_indices0` methods sometimes assert
that the return axes type is the same as the input.
Consequently, the implementation of `reduced_index` had better
return a range of the same type as the input.
This corrects the error in
https://github.com/JuliaArrays/OffsetArrays.jl/issues/92.
I'll put a workaround in OffsetArrays.jl too.
---
base/reducedim.jl | 2 +-
test/offsetarray.jl | 8 ++++++++
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/base/reducedim.jl b/base/reducedim.jl
index a448931499fc5..a66cb09cfe5c5 100644
--- a/base/reducedim.jl
+++ b/base/reducedim.jl
@@ -4,7 +4,7 @@
# for reductions that expand 0 dims to 1
reduced_index(i::OneTo) = OneTo(1)
-reduced_index(i::Union{Slice, IdentityUnitRange}) = first(i):first(i)
+reduced_index(i::Union{Slice, IdentityUnitRange}) = oftype(i, first(i):first(i))
reduced_index(i::AbstractUnitRange) =
throw(ArgumentError(
"""
diff --git a/test/offsetarray.jl b/test/offsetarray.jl
index bb25424d6855e..e7b4fb9410018 100644
--- a/test/offsetarray.jl
+++ b/test/offsetarray.jl
@@ -440,6 +440,14 @@ I = findall(!iszero, z)
@test std(A_3_3, dims=2) == OffsetArray(reshape([3,3,3], (3,1)), A_3_3.offsets)
@test sum(OffsetArray(fill(1,3000), -1000)) == 3000
+# https://github.com/JuliaArrays/OffsetArrays.jl/issues/92
+A92 = OffsetArray(reshape(1:27, 3, 3, 3), -2, -2, -2)
+B92 = view(A92, :, :, -1:0)
+@test axes(B92) == (-1:1, -1:1, 1:2)
+@test sum(B92, dims=(2,3)) == OffsetArray(reshape([51,57,63], Val(3)), -2, -2, 0)
+B92 = view(A92, :, :, Base.IdentityUnitRange(-1:0))
+@test sum(B92, dims=(2,3)) == OffsetArray(reshape([51,57,63], Val(3)), -2, -2, -2)
+
@test norm(v) ≈ norm(parent(v))
@test norm(A) ≈ norm(parent(A))
@test dot(v, v) ≈ dot(v0, v0)