Revert "Revert "Adding support for lu/lu! + SparseMatrixCSR{1}""

This reverts commit 0d6a94d.

Author: amartinhuertas

.vscode/settings.json

@@ -0,0 +1,2 @@
+{
+}

Project.toml

@@ -6,6 +6,7 @@ version = "0.6.3"
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+SuiteSparse = "4607b0f0-06f3-5cda-b6b1-a6196a1729e9"
 
 [compat]
 julia = "1"

src/SparseMatricesCSR.jl

@@ -2,9 +2,10 @@ module SparseMatricesCSR
 
 using SparseArrays
 using LinearAlgebra
+using SuiteSparse
 
 import Base: convert, copy, size, getindex, show, count, *, IndexStyle
-import LinearAlgebra: mul!
+import LinearAlgebra: mul!, lu, lu!
 import SparseArrays: nnz, getnzval, nonzeros, nzrange
 import SparseArrays: findnz, rowvals, getnzval, issparse
 

src/SparseMatrixCSR.jl

@@ -118,6 +118,20 @@ function Base.copy(a::SparseMatrixCSR{Bi}) where Bi
   SparseMatrixCSR{Bi}(a.m,a.n,copy(a.rowptr),copy(a.colval),copy(a.nzval))
 end
 
+function LinearAlgebra.lu(a::SparseMatrixCSR{0})
+  @assert false "Base.lu(a::SparseMatrixCSR{0}) not yet implemented"
+end
+
+function LinearAlgebra.lu(a::SparseMatrixCSR{1})
+  Transpose(lu(SparseMatrixCSC(a.m,a.n,a.rowptr,a.colval,a.nzval)))
+end
+
+function LinearAlgebra.lu!(
+    translu::Transpose{T,<:SuiteSparse.UMFPACK.UmfpackLU{T}},
+    a::SparseMatrixCSR{1}) where {T}
+  Transpose(lu!(translu.parent,SparseMatrixCSC(a.m,a.n,a.rowptr,a.colval,a.nzval)))
+end
+
 size(S::SparseMatrixCSR) = (S.m, S.n)
 IndexStyle(::Type{<:SparseMatrixCSR}) = IndexCartesian()
 function getindex(A::SparseMatrixCSR{Bi,T}, i0::Integer, i1::Integer) where {Bi,T}

test/SparseMatrixCSR.jl

@@ -82,7 +82,6 @@ function test_csr(Bi,Tv,Ti)
   @test y ≈ z
 
   @test CSR*x ≈ CSC*x
-
 end
 
 for Bi in (0,1)
@@ -93,4 +92,17 @@ for Bi in (0,1)
   end
 end
 
+I = [1,1,2,2,2,3,3]
+J = [1,2,1,2,3,2,3]
+V = [4.0,1.0,-1.0,4.0,1.0,-1.0,4.0]
+CSR=sparsecsr(I,J,V)
+CSC=sparse(I,J,V)
+x=rand(3)
+@test norm(CSR\x-CSC\x) < 1.0e-14
+fact=lu(CSR)
+lu!(fact,CSR)
+y=similar(x)
+ldiv!(y,fact,x)
+@test norm(y-CSC\x) < 1.0e-14
+
 end # module