Fix show of QRSparseQ (#311)

Author: dkarrasch

src/solvers/spqr.jl

@@ -357,20 +357,13 @@ function Base.show(io::IO, mime::MIME{Symbol("text/plain")}, F::QRSparse)
     println(io, "\nColumn permutation:")
     show(io, mime, F.pcol)
 end
-function Base.show(io::IO, ::MIME{Symbol("text/plain")}, Q::QRSparseQ)
-    summary(io, Q)
+# TODO: remove once the AdjointQ PR is merged
+if QRSparseQ <: AbstractMatrix
+    function Base.show(io::IO, ::MIME{Symbol("text/plain")}, Q::QRSparseQ)
+        summary(io, Q)
+    end
 end
 
-# With a real lhs and complex rhs with the same precision, we can reinterpret
-# the complex rhs as a real rhs with twice the number of columns
-#
-# This definition is similar to the definition in factorization.jl except that
-# here we have to use \ instead of ldiv! because of limitations in SPQR
-
-## Two helper methods
-_ret_size(F::QRSparse, b::AbstractVector) = (size(F, 2),)
-_ret_size(F::QRSparse, B::AbstractMatrix) = (size(F, 2), size(B, 2))
-
 """
     rank(::QRSparse{Tv,Ti}) -> Ti
 
@@ -385,6 +378,16 @@ Calculate rank of `S` by calculating its QR factorization. Values smaller than `
 """
 LinearAlgebra.rank(S::SparseMatrixCSC; tol=_default_tol(S)) = rank(qr(S; tol))
 
+# With a real lhs and complex rhs with the same precision, we can reinterpret
+# the complex rhs as a real rhs with twice the number of columns
+#
+# This definition is similar to the definition in factorization.jl except that
+# here we have to use \ instead of ldiv! because of limitations in SPQR
+
+## Two helper methods
+_ret_size(F::QRSparse, b::AbstractVector) = (size(F, 2),)
+_ret_size(F::QRSparse, B::AbstractMatrix) = (size(F, 2), size(B, 2))
+
 function (\)(F::QRSparse{T}, B::VecOrMat{Complex{T}}) where T<:LinearAlgebra.BlasReal
 # |z1|z3|  reinterpret  |x1|x2|x3|x4|  transpose  |x1|y1|  reshape  |x1|y1|x3|y3|
 # |z2|z4|      ->       |y1|y2|y3|y4|     ->      |x2|y2|     ->    |x2|y2|x4|y4|

test/spqr.jl

@@ -6,7 +6,7 @@ using Test
 using SparseArrays.SPQR
 using SparseArrays.CHOLMOD
 using LinearAlgebra: I, istriu, norm, qr, rank, rmul!, lmul!, Adjoint, Transpose, ColumnNorm, RowMaximum, NoPivot
-using SparseArrays: sparse, sprandn, spzeros, SparseMatrixCSC
+using SparseArrays: SparseArrays, sparse, sprandn, spzeros, SparseMatrixCSC
 
 if Base.USE_GPL_LIBS
 
@@ -16,6 +16,8 @@ nn = 100
 
 @test size(qr(sprandn(m, n, 0.1)).Q) == (m, m)
 
+@test repr("text/plain", qr(sprandn(4, 4, 0.5)).Q) == "4×4 $(SparseArrays.SPQR.QRSparseQ{Float64, Int})"
+
 @testset "element type of A: $eltyA" for eltyA in (Float64, ComplexF64)
     if eltyA <: Real
         A = sparse([1:n; rand(1:m, nn - n)], [1:n; rand(1:n, nn - n)], randn(nn), m, n)