Clean up preconditioner code

Author: ChrisRackauckas

src/common.jl

@@ -81,15 +81,13 @@ function SciMLBase.init(prob::LinearProblem, alg::Union{SciMLLinearSolveAlgorith
                         reltol=default_tol(eltype(prob.A)),
                         maxiters=length(prob.b),
                         verbose=false,
-                        Pl = nothing,
-                        Pr = nothing,
+                        Pl = Identity(),
+                        Pr = Identity(),
                         kwargs...,
                        )
     @unpack A, b, u0, p = prob
 
     u0 = (u0 !== nothing) ? u0 : zero(b)
-    Pl = (Pl !== nothing) ? Pl : Identity()
-    Pr = (Pr !== nothing) ? Pr : Identity()
 
     cacheval = init_cacheval(alg, A, b, u0, Pl, Pr, maxiters, abstol, reltol, verbose)
     isfresh = true

src/iterative_wrappers.jl

@@ -1,24 +1,18 @@
 ## Krylov.jl
 
-struct KrylovJL{F,Tl,Tr,I,A,K} <: AbstractKrylovSubspaceMethod
+struct KrylovJL{F,I,A,K} <: AbstractKrylovSubspaceMethod
     KrylovAlg::F
-    Pl::Tl
-    Pr::Tr
     gmres_restart::I
     window::I
     args::A
     kwargs::K
 end
 
 function KrylovJL(args...; KrylovAlg = Krylov.gmres!,
-                  Pl=nothing, Pr=nothing,
                   gmres_restart=0, window=0,
                   kwargs...)
 
-    Pl = (Pl === nothing) ? Identity() : Pl
-    Pr = (Pr === nothing) ? Identity() : Pr
-
-    return KrylovJL(KrylovAlg, Pl, Pr, gmres_restart, window,
+    return KrylovJL(KrylovAlg, gmres_restart, window,
                     args, kwargs)
 end
 
@@ -105,8 +99,8 @@ function SciMLBase.solve(cache::LinearCache, alg::KrylovJL; kwargs...)
         cache = set_cacheval(cache, solver)
     end
 
-    M = get_preconditioner(alg.Pl, cache.Pl)
-    N = get_preconditioner(alg.Pr, cache.Pr)
+    M = cache.Pl
+    N = cache.Pr
 
     M = (M === Identity()) ? I : inv(M)
     N = (N === Identity()) ? I : inv(N)
@@ -145,24 +139,18 @@ end
 
 ## IterativeSolvers.jl
 
-struct IterativeSolversJL{F,Tl,Tr,I,A,K} <: AbstractKrylovSubspaceMethod
+struct IterativeSolversJL{F,I,A,K} <: AbstractKrylovSubspaceMethod
     generate_iterator::F
-    Pl::Tl
-    Pr::Tr
     gmres_restart::I
     args::A
     kwargs::K
 end
 
 function IterativeSolversJL(args...;
                             generate_iterator = IterativeSolvers.gmres_iterable!,
-                            Pl=nothing, Pr=nothing,
                             gmres_restart=0, kwargs...)
 
-    Pl = (Pl === nothing) ? Identity() : Pl
-    Pr = (Pr === nothing) ? Identity() : Pr
-
-    return IterativeSolversJL(generate_iterator, Pl, Pr, gmres_restart,
+    return IterativeSolversJL(generate_iterator, gmres_restart,
                               args, kwargs)
 end
 
@@ -184,9 +172,6 @@ IterativeSolversJL_MINRES(args...;kwargs...) =
                        kwargs...)
 
 function init_cacheval(alg::IterativeSolversJL, A, b, u, Pl, Pr, maxiters, abstol, reltol, verbose)
-    Pl = get_preconditioner(alg.Pl, Pl)
-    Pr = get_preconditioner(alg.Pr, Pr)
-
     restart = (alg.gmres_restart == 0) ? min(20, size(A,1)) : alg.gmres_restart
 
     kwargs = (abstol=abstol, reltol=reltol, maxiter=maxiters,

src/preconditioners.jl

@@ -95,20 +95,3 @@ function LinearAlgebra.mul!(y, A::InvComposePreconditioner, x)
     @unpack P = A
     ldiv!(y, P, x)
 end
-
-function get_preconditioner(Pi, Po)
-
-    ifPi = Pi !== Identity()
-    ifPo = Po !== Identity()
-
-    P =
-    if ifPi & ifPo
-        ComposePreconditioner(Pi, Po)
-    elseif ifPi | ifPo
-        ifPi ? Pi : Po
-    else
-        Identity()
-    end
-
-    return P
-end