Correct +(::BlockDiagonal, ::StridedMatrix) for non-square blocks (#125)

* Add erroring test

* Fix `+(::BlockDiagonal,::StridedMatrix)` for non-square blocks

* Bump patch version

* Add addition test for dense `Matrix` with non-blocksquare `BlockDiagonal`

Author: mjp98

Project.toml

@@ -1,7 +1,7 @@
 name = "BlockDiagonals"
 uuid = "0a1fb500-61f7-11e9-3c65-f5ef3456f9f0"
 authors = ["Invenia Technical Computing Corporation"]
-version = "0.1.40"
+version = "0.1.41"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/base_maths.jl

@@ -33,11 +33,14 @@ function Base.:+(B::BlockDiagonal, M::StridedMatrix)
     end
     A = copy(M)
     row = 1
-    for (j, block) in enumerate(blocks(B))
-        nrows = size(block, 1)
-        rows = row:(row + nrows-1)
-        A[rows, rows] .+= block
+    col = 1
+    for block in blocks(B)
+        nrows, ncols = size(block)
+        rows = row:(row + nrows - 1)
+        cols = col:(col + ncols - 1)
+        A[rows, cols] .+= block
         row += nrows
+        col += ncols
     end
     return A
 end

test/base_maths.jl

@@ -22,6 +22,7 @@ using Test
     bi = BlockDiagonal([zeros(Int, N1, N1), zeros(Int, N2, N2), zeros(Int, N3, N3)])
 
     bns = BlockDiagonal([rand(rng, N1, N2), rand(rng, N2, N3), rand(rng, N3, N1)])
+    C = rand(rng, N, N)
 
     @testset "Addition" begin
         @testset "BlockDiagonal + BlockDiagonal" begin
@@ -35,6 +36,11 @@ using Test
             @test b1 + Matrix(b1) == b1 + b1
             @test_throws DimensionMismatch b1 + Matrix(b3)
 
+            # Test on non-square blocks
+            # https://github.com/invenia/BlockDiagonals.jl/issues/124
+            @test bns + Matrix(bns) == Matrix(bns) + Matrix(bns)
+            @test bns + C == Matrix(bns) + C
+
             # Matrix + BlockDiagonal
             @test Matrix(b1) + b1 isa Matrix
             @test Matrix(b1) + b1 == b1 + b1