sum for OneElement (#375)

* sum for OneElement

* Add tests

* Accept dims in sum

* Add tests

* Bump version to v1.13.0

* Ensure that init kwarg works

* Update tests for v1.6

---------

Co-authored-by: Sheehan Olver <[email protected]>

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "FillArrays"
 uuid = "1a297f60-69ca-5386-bcde-b61e274b549b"
-version = "1.12.0"
+version = "1.13.0"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/oneelement.jl

@@ -159,13 +159,6 @@ function *(A::OneElementMatrix, B::OneElementVecOrMat)
     OneElement(val, (A.ind[1], B.ind[2:end]...), (axes(A,1), axes(B)[2:end]...))
 end
 
-function *(A::AbstractFillMatrix, x::OneElementVector)
-    check_matmul_sizes(A, x)
-    val = getindex_value(A) * getindex_value(x)
-    Fill(val, (axes(A,1),))
-end
-*(A::AbstractZerosMatrix, x::OneElementVector) = mult_zeros(A, x)
-
 *(A::OneElementMatrix, x::AbstractZerosVector) = mult_zeros(A, x)
 
 function *(A::OneElementMatrix, B::AbstractFillVector)
@@ -448,3 +441,13 @@ _maybesize(t) = t
 Base.show(io::IO, A::OneElement) = print(io, OneElement, "(", A.val, ", ", A.ind, ", ", _maybesize(axes(A)), ")")
 Base.show(io::IO, A::OneElement{<:Any,1,Tuple{Int},Tuple{Base.OneTo{Int}}}) =
     print(io, OneElement, "(", A.val, ", ", A.ind[1], ", ", size(A,1), ")")
+
+# mapreduce
+Base.sum(O::OneElement; dims=:, kw...) = _sum(O, dims; kw...)
+_sum(O::OneElement, ::Colon; kw...) = sum((getindex_value(O),); kw...)
+function _sum(O::OneElement, dims; kw...)
+    v = _sum(O, :; kw...)
+    ax = Base.reduced_indices(axes(O), dims)
+    ind = ntuple(x -> x in dims ? first(ax[x]) + (O.ind[x] in axes(O)[x]) - 1 : O.ind[x], ndims(O))
+    OneElement(v, ind, ax)
+end

test/runtests.jl

@@ -2702,6 +2702,56 @@ end
         @test repr(B) == "OneElement(2, (1, 2), (Base.IdentityUnitRange(1:1), Base.IdentityUnitRange(2:2)))"
     end
 
+    @testset "sum" begin
+        @testset "OneElement($v, $ind, $sz)" for (v, ind, sz) in (
+                                    (Int8(2), 3, 4),
+                                    (3.0, 5, 4),
+                                    (3.0, 0, 0),
+                                    (SMatrix{2,2}(1:4), (4, 2), (12,6)),
+                                )
+            O = OneElement(v,ind,sz)
+            A = Array(O)
+            if VERSION >= v"1.10"
+                @test @inferred(sum(O)) === sum(A)
+            else
+                @test @inferred(sum(O)) == sum(A)
+            end
+            @test @inferred(sum(O, init=zero(eltype(O)))) === sum(A, init=zero(eltype(O)))
+            @test @inferred(sum(x->1, O, init=0)) === sum(Fill(1, axes(O)), init=0)
+        end
+
+        @testset for O in (OneElement(Int8(2), (1,2), (2,4)),
+                    OneElement(3, (1,2,3), (2,4,4)),
+                    OneElement(2.0, (3,2,5), (2,3,2)),
+                    OneElement(SMatrix{2,2}(1:4), (1,2), (2,4)),
+                )
+            A = Array(O)
+            init = sum((zero(FillArrays.getindex_value(O)),))
+            for i in 1:3
+                @test @inferred(sum(O, dims=i)) == sum(A, dims=i)
+                @test @inferred(sum(O, dims=i, init=init)) == sum(A, dims=i, init=init)
+                @test @inferred(sum(x->1, O, dims=i, init=0)) == sum(Fill(1, axes(O)), dims=i, init=0)
+            end
+            @test @inferred(sum(O, dims=1:1)) == sum(A, dims=1:1)
+            @test @inferred(sum(O, dims=1:2)) == sum(A, dims=1:2)
+            @test @inferred(sum(O, dims=1:3)) == sum(A, dims=1:3)
+            @test @inferred(sum(O, dims=(1,))) == sum(A, dims=(1,))
+            @test @inferred(sum(O, dims=(1,2))) == sum(A, dims=(1,2))
+            @test @inferred(sum(O, dims=(1,3))) == sum(A, dims=(1,3))
+            @test @inferred(sum(O, dims=(2,3))) == sum(A, dims=(2,3))
+            @test @inferred(sum(O, dims=(1,2,3))) == sum(A, dims=(1,2,3))
+            @test @inferred(sum(O, dims=1:1, init=init)) == sum(A, dims=1:1, init=init)
+            @test @inferred(sum(O, dims=1:2, init=init)) == sum(A, dims=1:2, init=init)
+            @test @inferred(sum(O, dims=1:3, init=init)) == sum(A, dims=1:3, init=init)
+            @test @inferred(sum(O, dims=(1,), init=init)) == sum(A, dims=(1,), init=init)
+            @test @inferred(sum(O, dims=(1,2), init=init)) == sum(A, dims=(1,2), init=init)
+            @test @inferred(sum(O, dims=(1,3), init=init)) == sum(A, dims=(1,3), init=init)
+            @test @inferred(sum(O, dims=(2,3), init=init)) == sum(A, dims=(2,3), init=init)
+            @test @inferred(sum(O, dims=(1,2,3), init=init)) == sum(A, dims=(1,2,3), init=init)
+            @test @inferred(sum(x->1, O, dims=(1,2,3), init=0)) == sum(Fill(1, axes(O)), dims=(1,2,3), init=0)
+        end
+    end
+
     @testset "diag" begin
         @testset for sz in [(0,0), (0,1), (1,0), (1,1), (4,4), (4,6), (6,3)], ind in CartesianIndices(sz)
             O = OneElement(4, Tuple(ind), sz)