WIP: fix KrylovJL_GMRES with Enzyme

Author: ChrisRackauckas

ext/LinearSolveEnzymeExt.jl

@@ -4,11 +4,13 @@ using LinearSolve
 using LinearSolve.LinearAlgebra
 isdefined(Base, :get_extension) ? (import Enzyme) : (import ..Enzyme)
 
-
 using Enzyme
 
 using EnzymeCore
 
+@inline EnzymeCore.EnzymeRules.inactive_type(v::Type{LinearSolve.KrylovJL}) = true
+@inline EnzymeCore.EnzymeRules.inactive_type(v::Type{LinearSolve.Krylov.GmresSolver}) = true
+
 function EnzymeCore.EnzymeRules.augmented_primal(config, func::Const{typeof(LinearSolve.init)}, ::Type{RT}, prob::EnzymeCore.Annotation{LP}, alg::Const; kwargs...) where {RT, LP <: LinearSolve.LinearProblem}
     res = func.val(prob.val, alg.val; kwargs...)
     dres = if EnzymeRules.width(config) == 1

test/enzyme.jl

@@ -107,7 +107,7 @@ Enzyme.autodiff(Reverse, f2, Duplicated(copy(A), dA), Duplicated(copy(b1), db1),
 @test db1 ≈ db12
 @test db2 ≈ db22
 
-#=
+
 function f3(A, b1, b2; alg = KrylovJL_GMRES())
     prob = LinearProblem(A, b1)
     cache = init(prob, alg)
@@ -117,9 +117,11 @@ function f3(A, b1, b2; alg = KrylovJL_GMRES())
     norm(s1 + s2)
 end
 
+dA = zeros(n, n);
+db1 = zeros(n);
+db2 = zeros(n);
 Enzyme.autodiff(Reverse, f3, Duplicated(copy(A), dA), Duplicated(copy(b1), db1), Duplicated(copy(b2), db2))
 
 @test dA ≈ dA2 atol=5e-5
 @test db1 ≈ db12
-@test db2 ≈ db22
-=#
+@test db2 ≈ db22