Allow linsolve to be \

Project.toml

@@ -1,7 +1,7 @@
 name = "NonlinearSolve"
 uuid = "8913a72c-1f9b-4ce2-8d82-65094dcecaec"
 authors = ["SciML"]
-version = "3.5.0"
+version = "3.5.1"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"

src/internal/linear_solve.jl

@@ -49,17 +49,11 @@ function reinit_cache!(cache::LinearSolverCache, args...; kwargs...)
     cache.nfactors = 0
 end
 
-@inline function LinearSolverCache(alg, linsolve, A::Number, b::Number, u; kwargs...)
-    return LinearSolverCache(nothing, nothing, A, b, nothing, 0, 0)
-end
-@inline function LinearSolverCache(alg, ::Nothing, A::SMatrix, b, u; kwargs...)
-    # Default handling for SArrays caching in LinearSolve is not the best. Override it here
-    return LinearSolverCache(nothing, nothing, A, b, nothing, 0, 0)
-end
-@inline function LinearSolverCache(alg, linsolve, A::Diagonal, b, u; kwargs...)
-    return LinearSolverCache(nothing, nothing, A, b, nothing, 0, 0)
-end
 function LinearSolverCache(alg, linsolve, A, b, u; kwargs...)
+    if (A isa Number && b isa Number) || (linsolve === nothing && A isa SMatrix) ||
+       (A isa Diagonal) || (linsolve isa typeof(\))
+        return LinearSolverCache(nothing, nothing, A, b, nothing, 0, 0)
+    end
     @bb b_ = copy(b)
     @bb u_ = copy(u)
     linprob = LinearProblem(A, b_; u0 = u_, kwargs...)
@@ -193,3 +187,4 @@ end
 @inline __needs_square_A(::Nothing, ::Number) = false
 @inline __needs_square_A(::Nothing, _) = false
 @inline __needs_square_A(linsolve, _) = LinearSolve.needs_square_A(linsolve)
+@inline __needs_square_A(::typeof(\), _) = false

src/utils.jl

@@ -18,6 +18,7 @@ end
 end
 
 @inline __needs_concrete_A(::Nothing) = false
+@inline __needs_concrete_A(::typeof(\)) = true
 @inline __needs_concrete_A(linsolve) = needs_concrete_A(linsolve)
 
 @inline __maybe_mutable(x, ::AutoSparseEnzyme) = __mutable(x)

test/core/rootfind.jl

@@ -72,7 +72,7 @@ const TERMINATION_CONDITIONS = [
         ]
 
         @testset "[IIP] u0: $(typeof(u0)) precs: $(_nameof(prec)) linsolve: $(_nameof(linsolve))" for u0 in ([
-                1.0, 1.0],), prec in precs, linsolve in (nothing, KrylovJL_GMRES())
+                1.0, 1.0],), prec in precs, linsolve in (nothing, KrylovJL_GMRES(), \)
             ad isa AutoZygote && continue
             if prec === :Random
                 prec = (args...) -> (Diagonal(randn!(similar(u0))), nothing)
@@ -139,7 +139,7 @@ end
         RadiusUpdateSchemes.NLsolve, RadiusUpdateSchemes.Hei, RadiusUpdateSchemes.Yuan,
         RadiusUpdateSchemes.Fan, RadiusUpdateSchemes.Bastin]
     u0s = ([1.0, 1.0], @SVector[1.0, 1.0], 1.0)
-    linear_solvers = [nothing, LUFactorization(), KrylovJL_GMRES()]
+    linear_solvers = [nothing, LUFactorization(), KrylovJL_GMRES(), \]
 
     @testset "[OOP] u0: $(typeof(u0)) radius_update_scheme: $(radius_update_scheme) linear_solver: $(linsolve)" for u0 in u0s,
         radius_update_scheme in radius_update_schemes, linsolve in linear_solvers
@@ -471,7 +471,7 @@ end
         precs = [NonlinearSolve.DEFAULT_PRECS, :Random]
 
         @testset "[IIP] u0: $(typeof(u0)) precs: $(_nameof(prec)) linsolve: $(_nameof(linsolve))" for u0 in ([
-                1.0, 1.0],), prec in precs, linsolve in (nothing, KrylovJL_GMRES())
+                1.0, 1.0],), prec in precs, linsolve in (nothing, KrylovJL_GMRES(), \)
             ad isa AutoZygote && continue
             if prec === :Random
                 prec = (args...) -> (Diagonal(randn!(similar(u0))), nothing)