document interaction with LinearSolve

Author: j-fu

README.md

@@ -14,14 +14,14 @@ The later is modeled after the linked list sparse matrix format described in the
 
 Any linear algebra method on `ExtendableSparseMatrix` starts with a `flush!` method which adds the LNK entries and the existing CSC entries into a new CSC struct and resets the LNK struct.
 
-`ExtendableSparseMatrix` is aimed to work as a drop-in replacement to `SparseMatrixCSC` in finite element and finite volume codes especally in those cases where the sparsity structure is hard to detect a priori and where working with an intermediadte COO representation appears to be not convenient.
+`ExtendableSparseMatrix` is aimed to work as a drop-in replacement to `SparseMatrixCSC` in finite element and finite volume codes especially in those cases where the sparsity structure is hard to detect a priori and where working with an intermediadte COO representation appears to be not convenient.
 
 
 
 ## Caveat
 
 This package assumes that a  $m \times n$  matrix is sparse if *each* row and *each* column have less than $C$ entries with
-$C << n$ and $C <<m$ . Adding a full matrix row will be a performance hit.
+$C << n$ and $C << m$ . Adding a full matrix row will be a performance hit.
 
 
 ## Working with ForwardDiff
@@ -59,6 +59,9 @@ For details, see the [corresponding documentation](https://j-fu.github.io/Extend
 
 
 ### Interfaces to other packages
+With version 0.7, the package becomes compatible with [LinearSolve.jl](https://github.com/SciML/LinearSolve.jl).
+Matrices of type `ExtendableSparseMatrix` can be passed to the `LinearProblem` constructor of [LinearSolve.jl](https://github.com/SciML/LinearSolve.jl).
+
 The package provides interfaces to other sparse matrix solvers and preconditioners. Dependencies on these
 packages are handeled via [Requires.jl](https://github.com/JuliaPackaging/Requires.jl).
 Currently, support includes:

docs/Project.toml

@@ -7,4 +7,5 @@ DocumenterTools = "35a29f4d-8980-5a13-9543-d66fff28ecb8"
 ExtendableSparse = "95c220a8-a1cf-11e9-0c77-dbfce5f500b3"
 IncompleteLU = "40713840-3770-5561-ab4c-a76e7d0d7895"
 IterativeSolvers = "42fd0dbc-a981-5370-80f2-aaf504508153"
+LinearSolve = "7ed4a6bd-45f5-4d41-b270-4a48e9bafcae"
 Pardiso = "46dd5b70-b6fb-5a00-ae2d-e8fea33afaf2"

docs/make.jl

@@ -1,19 +1,24 @@
 push!(LOAD_PATH,"../src/")
-using Documenter, ExtendableSparse,Pardiso,AlgebraicMultigrid,IncompleteLU
+using Documenter, ExtendableSparse,Pardiso,AlgebraicMultigrid,IncompleteLU,LinearSolve
 
-makedocs(sitename="ExtendableSparse.jl",
-         modules = [ExtendableSparse],
-         doctest = true,
-         clean = false,
-         authors = "J. Fuhrmann",
-         repo="https://github.com/j-fu/ExtendableSparse.jl",
-         pages=[
-             "Home"=>"index.md",
-             "example.md",
-             "extsparse.md",
-             "iter.md",
-             "internal.md",
-             "changes.md",
-         ])
+function mkdocs()
+    makedocs(sitename="ExtendableSparse.jl",
+             modules = [ExtendableSparse],
+             doctest = true,
+             clean = false,
+             authors = "J. Fuhrmann",
+             repo="https://github.com/j-fu/ExtendableSparse.jl",
+             pages=[
+                 "Home"=>"index.md",
+                 "example.md",
+                 "extsparse.md",
+                 "iter.md",
+                 "linearsolve.md",
+                 "internal.md",
+                 "changes.md",
+             ])
+end
+
+mkdocs()
 
 deploydocs(repo = "github.com/j-fu/ExtendableSparse.jl.git")

docs/src/changes.md

@@ -1,4 +1,9 @@
 # Changes
+## v0.7, August 19, 2022
+- Require Julia 1.6
+- first steps to compatibility with LinearSolve.jl
+## v0.6, April 20, 2021
+- use type parameters to describe factorizations
 ## v0.5, April 10, 2021
 - Introduce lu/lu! , factorize/factorize!, unifying LU factorizations and preconditioners
 - Interface packages: Pardiso, AlgebraicMultigrid, IncompleteLU via Requires.jl

docs/src/linearsolve.md

@@ -0,0 +1,44 @@
+# Integration with LinearSolve.jl
+
+Starting with version 0.7, ExtendableSparse tries to become compatible
+with [LinearSolve.jl](https://github.com/SciML/LinearSolve.jl). 
+For this purpose, it extends the `LinearProblem` constructor and the
+`set_A` function by methods specific for `ExtendableSparseMatrix`.
+
+```@docs
+LinearSolve.LinearProblem(::ExtendableSparseMatrix,x,p;kwargs...)
+LinearSolve.set_A(::LinearSolve.LinearCache,::ExtendableSparseMatrix)
+```
+
+We can create a test problem and solve it with the `\` operator.
+```@example
+using ExtendableSparse # hide
+A=fdrand(10,10,10,matrixtype=ExtendableSparseMatrix)
+x=ones(1000)
+b=A*x
+y=A\b
+sum(y)
+```
+
+The same problem can be solved by the tools available via `LinearSolve.jl`:
+```@example
+using ExtendableSparse # hide
+using LinearSolve # hide
+A=fdrand(10,10,10,matrixtype=ExtendableSparseMatrix)
+x=ones(1000)
+b=A*x
+y=solve(LinearProblem(A,b),KLUFactorization()).u
+sum(y)
+```
+
+
+Also, the iterative method interface works with the preconditioners defined in this package.
+```@example
+using ExtendableSparse # hide
+using LinearSolve # hide
+A=fdrand(10,10,10,matrixtype=ExtendableSparseMatrix)
+x=ones(1000)
+b=A*x
+y=LinearSolve.solve(LinearProblem(A,b),IterativeSolversJL_CG(),Pl=ILU0Preconditioner(A)).u
+sum(y)
+```

src/extendable.jl

@@ -230,7 +230,12 @@ $(SIGNATURES)
 """
 function SparseArrays.rowvals(ext::ExtendableSparseMatrix)
     @inbounds flush!(ext)
-    return rowvals(ext.cscmatrix)
+    rowvals(ext.cscmatrix)
+end
+
+function SparseArrays.getrowval(S::ExtendableSparseMatrix)
+    flush!(S)
+    getfield(S.cscmatrix, :rowval)
 end
 
 
@@ -239,7 +244,7 @@ $(SIGNATURES)
 
 [`flush!`](@ref) and return colptr of  in ext.cscmatrix.
 """
-function colptrs(ext::ExtendableSparseMatrix)
+function SparseArrays.getcolptr(ext::ExtendableSparseMatrix)
     @inbounds flush!(ext)
     return ext.cscmatrix.colptr
 end