Make concatenations involving combinations of special matrices with s…

…pecial matrices, sparse matrices, or dense matrices/vectors yield sparse arrays.
JuliaLang · Jul 28, 2016 · fea7504 · fea7504
1 parent e18ae9e
commit fea7504
Show file tree

Hide file tree

Showing 2 changed files with 42 additions and 3 deletions.
diff --git a/base/sparse/sparsematrix.jl b/base/sparse/sparsematrix.jl
@@ -3231,17 +3231,21 @@ end
 
 # Sparse/dense concatenation
 
-function hcat(Xin::Union{Vector, Matrix, SparseMatrixCSC}...)
+# TODO: A similar definition also exists in base/linalg/bidiag.jl. These definitions should
+# be consolidated in a more appropriate location, for example base/linalg/special.jl.
+SpecialArrays = Union{Diagonal, Bidiagonal, Tridiagonal, SymTridiagonal}
+
+function hcat(Xin::Union{Vector, Matrix, SparseMatrixCSC, SpecialArrays}...)
     X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
     hcat(X...)
 end
 
-function vcat(Xin::Union{Vector, Matrix, SparseMatrixCSC}...)
+function vcat(Xin::Union{Vector, Matrix, SparseMatrixCSC, SpecialArrays}...)
     X = SparseMatrixCSC[issparse(x) ? x : sparse(x) for x in Xin]
     vcat(X...)
 end
 
-function hvcat(rows::Tuple{Vararg{Int}}, X::Union{Vector, Matrix, SparseMatrixCSC}...)
+function hvcat(rows::Tuple{Vararg{Int}}, X::Union{Vector, Matrix, SparseMatrixCSC, SpecialArrays}...)
     nbr = length(rows)  # number of block rows
 
     tmp_rows = Array{SparseMatrixCSC}(nbr)

diff --git a/test/linalg/special.jl b/test/linalg/special.jl
@@ -128,3 +128,38 @@ for typ in [UpperTriangular,LowerTriangular,Base.LinAlg.UnitUpperTriangular,Base
     @test Base.LinAlg.A_mul_Bc(atri,qrb[:Q]) ≈ full(atri) * qrb[:Q]'
     @test Base.LinAlg.A_mul_Bc!(copy(atri),qrb[:Q]) ≈ full(atri) * qrb[:Q]'
 end
+
+# Test that concatenations of combinations of special and other matrix types yield sparse arrays
+let
+    N = 4
+    # Test concatenating pairwise combinations of special matrices
+    diagmat = Diagonal(ones(N))
+    bidiagmat = Bidiagonal(ones(N), ones(N-1), true)
+    tridiagmat = Tridiagonal(ones(N-1), ones(N), ones(N-1))
+    symtridiagmat = SymTridiagonal(ones(N), ones(N-1))
+    specialmats = (diagmat, bidiagmat, tridiagmat, symtridiagmat)
+    for specialmata in specialmats, specialmatb in specialmats
+        @test issubtype(typeof(hcat(specialmata, specialmatb)), AbstractSparseArray)
+        @test issubtype(typeof(vcat(specialmata, specialmatb)), AbstractSparseArray)
+        @test issubtype(typeof(hvcat((1,1), specialmata, specialmatb)), AbstractSparseArray)
+    end
+    # Test concatenating pairwise combinations of special matrices with sparse or dense matrices
+    spmat = spdiagm(ones(N))
+    densemat = diagm(ones(N))
+    for specialmat in specialmats, othermat in (spmat, densemat)
+        @test issubtype(typeof(hcat(specialmat, spmat)), AbstractSparseArray)
+        @test issubtype(typeof(hcat(spmat, specialmat)), AbstractSparseArray)
+        @test issubtype(typeof(vcat(specialmat, spmat)), AbstractSparseArray)
+        @test issubtype(typeof(vcat(spmat, specialmat)), AbstractSparseArray)
+        @test issubtype(typeof(hvcat((1,1), specialmat, spmat)), AbstractSparseArray)
+        @test issubtype(typeof(hvcat((1,1), spmat, specialmat)), AbstractSparseArray)
+    end
+    # Test concatenating combinations of special matrices and dense vectors
+    densevec = ones(N)
+    for specialmat in specialmats
+        @test issubtype(typeof(hcat(specialmat, densevec)), AbstractSparseArray)
+        @test issubtype(typeof(hcat(densevec, specialmat)), AbstractSparseArray)
+        @test issubtype(typeof(hvcat((2,), specialmat, densevec)), AbstractSparseArray)
+        @test issubtype(typeof(hvcat((2,), densevec, specialmat)), AbstractSparseArray)
+    end
+end