Refactor CudaOffloadFactorization into LU and QR variants

ext/LinearSolveCUDAExt.jl

@@ -5,7 +5,7 @@ using LinearSolve: LinearSolve, is_cusparse, defaultalg, cudss_loaded, DefaultLi
                    DefaultAlgorithmChoice, ALREADY_WARNED_CUDSS, LinearCache,
                    needs_concrete_A,
                    error_no_cudss_lu, init_cacheval, OperatorAssumptions,
-                   CudaOffloadFactorization,
+                   CudaOffloadFactorization, CudaOffloadLUFactorization, CudaOffloadQRFactorization,
                    SparspakFactorization, KLUFactorization, UMFPACKFactorization
 using LinearSolve.LinearAlgebra, LinearSolve.SciMLBase, LinearSolve.ArrayInterface
 using SciMLBase: AbstractSciMLOperator
@@ -35,6 +35,43 @@ function LinearSolve.error_no_cudss_lu(A::CUDA.CUSPARSE.CuSparseMatrixCSR)
     nothing
 end
 
+function SciMLBase.solve!(cache::LinearSolve.LinearCache, alg::CudaOffloadLUFactorization;
+        kwargs...)
+    if cache.isfresh
+        fact = lu(CUDA.CuArray(cache.A))
+        cache.cacheval = fact
+        cache.isfresh = false
+    end
+    y = Array(ldiv!(CUDA.CuArray(cache.u), cache.cacheval, CUDA.CuArray(cache.b)))
+    cache.u .= y
+    SciMLBase.build_linear_solution(alg, y, nothing, cache)
+end
+
+function LinearSolve.init_cacheval(alg::CudaOffloadLUFactorization, A, b, u, Pl, Pr,
+        maxiters::Int, abstol, reltol, verbose::Bool,
+        assumptions::OperatorAssumptions)
+    lu(CUDA.CuArray(A))
+end
+
+function SciMLBase.solve!(cache::LinearSolve.LinearCache, alg::CudaOffloadQRFactorization;
+        kwargs...)
+    if cache.isfresh
+        fact = qr(CUDA.CuArray(cache.A))
+        cache.cacheval = fact
+        cache.isfresh = false
+    end
+    y = Array(ldiv!(CUDA.CuArray(cache.u), cache.cacheval, CUDA.CuArray(cache.b)))
+    cache.u .= y
+    SciMLBase.build_linear_solution(alg, y, nothing, cache)
+end
+
+function LinearSolve.init_cacheval(alg::CudaOffloadQRFactorization, A, b, u, Pl, Pr,
+        maxiters::Int, abstol, reltol, verbose::Bool,
+        assumptions::OperatorAssumptions)
+    qr(CUDA.CuArray(A))
+end
+
+# Keep the deprecated CudaOffloadFactorization working by forwarding to QR
 function SciMLBase.solve!(cache::LinearSolve.LinearCache, alg::CudaOffloadFactorization;
         kwargs...)
     if cache.isfresh

lib/LinearSolveAutotune/src/algorithms.jl

@@ -84,10 +84,10 @@ function get_gpu_algorithms(; skip_missing_algs::Bool = false)
     # CUDA algorithms
     if is_cuda_available()
         try
-            push!(gpu_algs, CudaOffloadFactorization())
-            push!(gpu_names, "CudaOffloadFactorization")
+            push!(gpu_algs, CudaOffloadLUFactorization())
+            push!(gpu_names, "CudaOffloadLUFactorization")
         catch e
-            msg = "CUDA hardware detected but CudaOffloadFactorization not available: $e. Load CUDA.jl package."
+            msg = "CUDA hardware detected but CudaOffloadLUFactorization not available: $e. Load CUDA.jl package."
             if skip_missing_algs
                 @warn msg
             else

src/LinearSolve.jl

@@ -255,6 +255,8 @@ export SimpleGMRES
 
 export HYPREAlgorithm
 export CudaOffloadFactorization
+export CudaOffloadLUFactorization
+export CudaOffloadQRFactorization
 export MKLPardisoFactorize, MKLPardisoIterate
 export PanuaPardisoFactorize, PanuaPardisoIterate
 export PardisoJL

src/extension_algs.jl

@@ -61,23 +61,70 @@ struct HYPREAlgorithm <: SciMLLinearSolveAlgorithm
     end
 end
 
+# Debug: About to define CudaOffloadLUFactorization
+"""
+`CudaOffloadLUFactorization()`
+
+An offloading technique used to GPU-accelerate CPU-based computations using LU factorization.
+Requires a sufficiently large `A` to overcome the data transfer costs.
+
+!!! note
+
+    Using this solver requires adding the package CUDA.jl, i.e. `using CUDA`
+"""
+struct CudaOffloadLUFactorization <: AbstractFactorization
+    function CudaOffloadLUFactorization()
+        ext = Base.get_extension(@__MODULE__, :LinearSolveCUDAExt)
+        if ext === nothing
+            error("CudaOffloadLUFactorization requires that CUDA is loaded, i.e. `using CUDA`")
+        else
+            return new()
+        end
+    end
+end
+
+"""
+`CudaOffloadQRFactorization()`
+
+An offloading technique used to GPU-accelerate CPU-based computations using QR factorization.
+Requires a sufficiently large `A` to overcome the data transfer costs.
+
+!!! note
+
+    Using this solver requires adding the package CUDA.jl, i.e. `using CUDA`
+"""
+struct CudaOffloadQRFactorization <: AbstractFactorization
+    function CudaOffloadQRFactorization()
+        ext = Base.get_extension(@__MODULE__, :LinearSolveCUDAExt)
+        if ext === nothing
+            error("CudaOffloadQRFactorization requires that CUDA is loaded, i.e. `using CUDA`")
+        else
+            return new()
+        end
+    end
+end
+
 """
 `CudaOffloadFactorization()`
 
+!!! warning
+    This algorithm is deprecated. Use `CudaOffloadQRFactorization()` instead.
+
 An offloading technique used to GPU-accelerate CPU-based computations.
 Requires a sufficiently large `A` to overcome the data transfer costs.
 
 !!! note
 
     Using this solver requires adding the package CUDA.jl, i.e. `using CUDA`
 """
-struct CudaOffloadFactorization <: LinearSolve.AbstractFactorization
+struct CudaOffloadFactorization <: AbstractFactorization
     function CudaOffloadFactorization()
+        Base.depwarn("`CudaOffloadFactorization` is deprecated, use `CudaOffloadQRFactorization` instead.", :CudaOffloadFactorization)
         ext = Base.get_extension(@__MODULE__, :LinearSolveCUDAExt)
         if ext === nothing
             error("CudaOffloadFactorization requires that CUDA is loaded, i.e. `using CUDA`")
         else
-            return new{}()
+            return new()
         end
     end
 end

test/gpu/cuda.jl

@@ -45,7 +45,7 @@ function test_interface(alg, prob1, prob2)
     return
 end
 
-@testset "$alg" for alg in (CudaOffloadFactorization(), NormalCholeskyFactorization())
+@testset "$alg" for alg in (CudaOffloadFactorization(), CudaOffloadLUFactorization(), CudaOffloadQRFactorization(), NormalCholeskyFactorization())
     test_interface(alg, prob1, prob2)
 end
 

test/resolve.jl

@@ -11,6 +11,8 @@ for alg in vcat(InteractiveUtils.subtypes(AbstractDenseFactorization),
     if !(alg in [
            DiagonalFactorization,
            CudaOffloadFactorization,
+           CudaOffloadLUFactorization,
+           CudaOffloadQRFactorization,
            CUSOLVERRFFactorization,
            AppleAccelerateLUFactorization,
            MetalLUFactorization