Merge pull request #105 from invenia/mz/convert

Convert between `BlockDiagonals` of different block types
JuliaArrays · Jun 22, 2022 · 1ab40c9 · 1ab40c9 · mzgubic · Jun 22, 2022
2 parents f920f23 + 3e3d38c
commit 1ab40c9
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diff --git a/src/blockdiagonal.jl b/src/blockdiagonal.jl
@@ -142,6 +142,11 @@ end
  @inbounds return p > 0 ? getblock(B, p)[i, end + j] : zero(T)
 end
 
+function Base.convert(::Type{BlockDiagonal{T, M}}, b::BlockDiagonal) where {T, M}
+ new_blocks = convert.(M, blocks(b))
+ return BlockDiagonal(new_blocks)::BlockDiagonal{T, M}
+end
+
 # Transform indices `i, j` (identifying entry `Matrix(B)[i, j]`) into indices `p, i, j` such
 # that the same entry is available via `getblock(B, p)[i, end+j]`; `p = -1` if no such `p`.
 function _block_indices(B::BlockDiagonal, i::Integer, j::Integer)

diff --git a/test/blockdiagonal.jl b/test/blockdiagonal.jl
@@ -129,4 +129,16 @@ using Test
  b = BlockDiagonal(AbstractMatrix{Float64}[ones(2, 2)])
  @test b[1] == 1
  end
+
+ @testset "convert(BlockDiagonal{F, T{F}}, block_diagonal)" for T in (
+ Symmetric, UpperTriangular, Transpose, Hermitian
+ )
+ special = T(rand(2, 2))
+ b = BlockDiagonal([special])
+
+ convert_first = BlockDiagonal([convert(Matrix, special)])
+ convert_last = convert(BlockDiagonal{Float64, Matrix{Float64}}, b)
+
+ @test convert_first == convert_last
+ end
 end