Add preconditioner builder for BoomerAMG

Project.toml

@@ -6,6 +6,7 @@ version = "1.1.0"
 CEnum = "fa961155-64e5-5f13-b03f-caf6b980ea82"
 HYPRE_jll = "0a602bbd-b08b-5d75-8d32-0de6eef44785"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MPI = "da04e1cc-30fd-572f-bb4f-1f8673147195"
 PartitionedArrays = "5a9dfac6-5c52-46f7-8278-5e2210713be9"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
@@ -13,6 +14,7 @@ SparseMatricesCSR = "a0a7dd2c-ebf4-11e9-1f05-cf50bc540ca1"
 
 [compat]
 CEnum = "0.4"
+LinearAlgebra = "1"
 MPI = "0.19, 0.20"
 PartitionedArrays = "0.2"
 SparseMatricesCSR = "0.6"

src/HYPRE.jl

@@ -5,7 +5,7 @@ module HYPRE
 using MPI: MPI
 using PartitionedArrays: IndexRange, MPIData, PSparseMatrix, PVector, PartitionedArrays,
     SequentialData, map_parts
-using SparseArrays: SparseArrays, SparseMatrixCSC, nnz, nonzeros, nzrange, rowvals
+using SparseArrays: SparseArrays, AbstractSparseMatrixCSC, SparseMatrixCSC, nnz, nonzeros, nzrange, rowvals
 using SparseMatricesCSR: SparseMatrixCSR, colvals, getrowptr
 
 export HYPREMatrix, HYPREVector
@@ -528,4 +528,7 @@ end
 include("solvers.jl")
 include("solver_options.jl")
 
+# LinearSolve preconditioner interface
+include("precs.jl")
+
 end # module HYPRE

src/precs.jl

@@ -0,0 +1,35 @@
+import LinearAlgebra
+
+struct BoomerAMGPrecWrapper{MatType}
+    P::HYPRE.BoomerAMG
+    A::MatType
+end
+
+function LinearAlgebra.ldiv!(y::AbstractVector, prec::BoomerAMGPrecWrapper, x::AbstractVector)
+    fill!(y, eltype(y)(0.0))
+    HYPRE.solve!(prec.P, y, prec.A, x)
+end
+
+"""
+    BoomerAMGPrecBuilder(settings_fun; kwargs...)
+"""
+struct BoomerAMGPrecBuilder{SFun, Tk}
+    settings_fun!::SFun
+    kwargs::Tk
+end
+
+# Syntactic sugar wth some defaults
+function BoomerAMGPrecBuilder(settings_fun! = (amg, A, p) -> nothing; MaxIter = 1, Tol = 0.0, kwargs...)
+    return construct_boomeramg_prec_builder(settings_fun!; MaxIter, Tol, kwargs)
+end
+
+# Helper to package kwargs
+function construct_boomeramg_prec_builder(settings_fun!; kwargs...)
+    return BoomerAMGPrecBuilder(settings_fun!, kwargs)
+end
+
+function (b::BoomerAMGPrecBuilder)(A::AbstractSparseMatrixCSC, p)
+    amg = HYPRE.BoomerAMG(; b.kwargs)
+    settings_fun!(amg, A, p)
+    return (BoomerAMGPrecWrapper(amg, A), I)
+end

test/runtests.jl

@@ -9,6 +9,7 @@ using PartitionedArrays
 using SparseArrays
 using SparseMatricesCSR
 using Test
+using LinearSolve
 
 # Init HYPRE and MPI
 HYPRE.Init()
@@ -18,6 +19,28 @@ HYPRE.Init()
     @test LibHYPRE.VERSION.major == 2
 end
 
+@testset "use as LinearSolve.jl preconditioner" begin
+    # Setup
+    A = sprand(100, 100, 0.05); A = A'A + 5I
+    b = rand(100)
+    x = zeros(100)
+    # Solve
+    tol = 1e-9
+    function set_debug_printlevel(amg, A, p)
+        HYPRE.HYPRE_BoomerAMGSetPrintLevel(amg, 3)
+    end
+    bamg = HYPRE.BoomerAMGPrecBuilder(
+        (amg, A, p) -> nothing;
+        MaxIter = 1,
+        Tol = tol,
+    )
+    prob = LinearProblem(A, b)
+    solver = KrylovJL_CG(precs = bamg)
+    x = solve(prob, solver, atol=1.0e-14)
+    @test x ≈ A \ b atol=tol
+end
+
+
 @testset "HYPREMatrix" begin
     H = HYPREMatrix(MPI.COMM_WORLD, 1, 5)
     @test H.ijmatrix != HYPRE_IJMatrix(C_NULL)
@@ -654,3 +677,4 @@ end
     x = HYPRE.solve(pcg, A, b)
     @test x ≈ A \ b atol=tol
 end
+