Use solution object in all solvers

benchmark/simple_pendulum.jl

@@ -18,12 +18,6 @@ function bc_pendulum!(residual, u, p, t)
     return nothing
 end
 
-function bc_pendulum_mirk!(residual, u, p, t)
-    residual[1] = u[:, end ÷ 2][1] + π / 2
-    residual[2] = u[:, end][1] - π / 2
-    return nothing
-end
-
 function simple_pendulum(u, p, t)
     g, L, θ, dθ = 9.81, 1.0, u[1], u[2]
     return [dθ, -(g / L) * sin(θ)]
@@ -34,16 +28,8 @@ function bc_pendulum(u, p, t)
     return [u((t0 + t1) / 2)[1] + π / 2, u(t1)[1] - π / 2]
 end
 
-function bc_pendulum_mirk(u, p, t)
-    return [u[:, end ÷ 2][1] + π / 2, u[:, end][1] - π / 2]
-end
-
 const prob_oop = BVProblem{false}(simple_pendulum, bc_pendulum, [π / 2, π / 2], tspan)
 const prob_iip = BVProblem{true}(simple_pendulum!, bc_pendulum!, [π / 2, π / 2], tspan)
-const prob_oop_mirk = BVProblem{false}(
-    simple_pendulum, bc_pendulum_mirk, [π / 2, π / 2], tspan)
-const prob_iip_mirk = BVProblem{true}(
-    simple_pendulum!, bc_pendulum_mirk!, [π / 2, π / 2], tspan)
 
 end
 
@@ -77,7 +63,7 @@ function create_simple_pendulum_benchmark()
     for alg in (MIRK2, MIRK3, MIRK4, MIRK5, MIRK6)
         if @isdefined(alg)
             iip_suite["$alg()"] = @benchmarkable solve(
-                $SimplePendulumBenchmark.prob_iip_mirk, $alg(), dt = 0.05)
+                $SimplePendulumBenchmark.prob_iip, $alg(), dt = 0.05)
         end
     end
 
@@ -102,7 +88,7 @@ function create_simple_pendulum_benchmark()
     for alg in (MIRK2, MIRK3, MIRK4, MIRK5, MIRK6)
         if @isdefined(alg)
             oop_suite["$alg()"] = @benchmarkable solve(
-                $SimplePendulumBenchmark.prob_oop_mirk, $alg(), dt = 0.05)
+                $SimplePendulumBenchmark.prob_oop, $alg(), dt = 0.05)
         end
     end
 

lib/BoundaryValueDiffEqCore/src/misc_utils.jl

@@ -1,7 +1,6 @@
 # Intermidiate solution evaluation
-@concrete struct EvalSol{iip}
+@concrete struct EvalSol{C}
     u
     t
-    alg
-    k_discrete
+    cache::C
 end

lib/BoundaryValueDiffEqCore/src/utils.jl

@@ -223,7 +223,7 @@ end
 __vec_f(u, p, t, f, u_size) = vec(f(reshape(u, u_size), p, t))
 
 function __vec_bc!(resid, sol, p, t, bc!, resid_size, u_size)
-    bc!(reshape(resid, resid_size), __restructure_sol(sol, u_size), p, t)
+    bc!(reshape(resid, resid_size), sol, p, t)
     return nothing
 end
 
@@ -232,17 +232,19 @@ function __vec_bc!(resid, sol, p, bc!, resid_size, u_size)
     return nothing
 end
 
-__vec_bc(sol, p, t, bc, u_size) = vec(bc(__restructure_sol(sol, u_size), p, t))
+__vec_bc(sol, p, t, bc, u_size) = vec(bc(sol, p, t))
 __vec_bc(sol, p, bc, u_size) = vec(bc(reshape(sol, u_size), p))
 
 @inline __get_non_sparse_ad(ad::AbstractADType) = ad
 @inline __get_non_sparse_ad(ad::AutoSparse) = ADTypes.dense_ad(ad)
 
 # Restructure Solution
 function __restructure_sol(sol::AbstractVectorOfArray, u_size)
+    (size(first(sol)) == u_size) && return sol
     return VectorOfArray(map(Base.Fix2(reshape, u_size), sol))
 end
-function __restructure_sol(sol::Vector{<:AbstractArray}, u_size)
+function __restructure_sol(sol::AbstractArray{<:AbstractArray}, u_size)
+    (size(first(sol)) == u_size) && return sol
     return map(Base.Fix2(reshape, u_size), sol)
 end
 

lib/BoundaryValueDiffEqFIRK/src/BoundaryValueDiffEqFIRK.jl

@@ -15,15 +15,16 @@ import BoundaryValueDiffEqCore: BoundaryValueDiffEqAlgorithm, BVPJacobianAlgorit
                                 recursive_flatten, recursive_flatten!, recursive_unflatten!,
                                 __concrete_nonlinearsolve_algorithm, diff!,
                                 __FastShortcutBVPCompatibleNonlinearPolyalg,
-                                __FastShortcutBVPCompatibleNLLSPolyalg,
+                                __FastShortcutBVPCompatibleNLLSPolyalg, EvalSol,
                                 concrete_jacobian_algorithm, eval_bc_residual,
                                 eval_bc_residual!, get_tmp, __maybe_matmul!,
                                 __append_similar!, __extract_problem_details,
                                 __initial_guess, __maybe_allocate_diffcache,
-                                __get_bcresid_prototype, __similar, __vec, __vec_f,
-                                __vec_f!, __vec_bc, __vec_bc!, recursive_flatten_twopoint!,
-                                __internal_nlsolve_problem, MaybeDiffCache, __extract_mesh,
-                                __extract_u0, __has_initial_guess, __initial_guess_length,
+                                __restructure_sol, __get_bcresid_prototype, __similar,
+                                __vec, __vec_f, __vec_f!, __vec_bc, __vec_bc!,
+                                recursive_flatten_twopoint!, __internal_nlsolve_problem,
+                                MaybeDiffCache, __extract_mesh, __extract_u0,
+                                __has_initial_guess, __initial_guess_length,
                                 __initial_guess_on_mesh, __flatten_initial_guess,
                                 __build_solution, __Fix3, __sparse_jacobian_cache,
                                 __sparsity_detection_alg, _sparse_like, ColoredMatrix
@@ -33,7 +34,7 @@ import ArrayInterface: matrix_colors, parameterless_type, undefmatrix, fast_scal
 import ConcreteStructs: @concrete
 import DiffEqBase: solve
 import FastClosures: @closure
-import ForwardDiff: ForwardDiff, pickchunksize
+import ForwardDiff: ForwardDiff, pickchunksize, Dual
 import Logging
 import RecursiveArrayTools: ArrayPartition, DiffEqArray
 import SciMLBase: AbstractDiffEqInterpolation, StandardBVProblem, __solve, _unwrap_val
@@ -60,11 +61,11 @@ include("sparse_jacobians.jl")
     f1 = (u, p, t) -> [u[2], 0]
 
     function bc1!(residual, u, p, t)
-        residual[1] = u[:, 1][1] - 5
-        residual[2] = u[:, end][1]
+        residual[1] = u(0.0)[1] - 5
+        residual[2] = u(5.0)[1]
     end
 
-    bc1 = (u, p, t) -> [u[:, 1][1] - 5, u[:, end][1]]
+    bc1 = (u, p, t) -> [u(0.0)[1] - 5, u(5.0)[1]]
 
     bc1_a! = (residual, ua, p) -> (residual[1] = ua[1] - 5)
     bc1_b! = (residual, ub, p) -> (residual[1] = ub[1])
@@ -143,14 +144,14 @@ include("sparse_jacobians.jl")
     f1_nlls = (u, p, t) -> [u[2], -u[1]]
 
     bc1_nlls! = (resid, sol, p, t) -> begin
-        solₜ₁ = sol[:, 1]
-        solₜ₂ = sol[:, end]
+        solₜ₁ = sol(0.0)
+        solₜ₂ = sol(100.0)
         resid[1] = solₜ₁[1]
         resid[2] = solₜ₂[1] - 1
         resid[3] = solₜ₂[2] + 1.729109
         return nothing
     end
-    bc1_nlls = (sol, p, t) -> [sol[:, 1][1], sol[:, end][1] - 1, sol[:, end][2] + 1.729109]
+    bc1_nlls = (sol, p, t) -> [sol(0.0)[1], sol(100.0)[1] - 1, sol(100.0)[2] + 1.729109]
 
     bc1_nlls_a! = (resid, ua, p) -> (resid[1] = ua[1])
     bc1_nlls_b! = (resid, ub, p) -> (resid[1] = ub[1] - 1;

lib/BoundaryValueDiffEqFIRK/src/adaptivity.jl

@@ -390,10 +390,10 @@ function apply_q_prime(τ, h, coeffs)
     return sum(i * coeffs[i] * (τ * h)^(i - 1) for i in axes(coeffs, 1))
 end
 
-function eval_q(y_i, τ, h, A, K)
+function eval_q(y_i::AbstractArray{T}, τ, h, A, K) where {T}
     M = size(K, 1)
-    q = zeros(M)
-    q′ = zeros(M)
+    q = zeros(T, M)
+    q′ = zeros(T, M)
     for i in 1:M
         ki = @view K[i, :]
         coeffs = get_q_coeffs(A, ki, h)

lib/BoundaryValueDiffEqFIRK/src/firk.jl

@@ -353,7 +353,7 @@ end
 
 function __perform_firk_iteration(cache::Union{FIRKCacheExpand, FIRKCacheNested}, abstol,
         adaptive::Bool; nlsolve_kwargs = (;), kwargs...)
-    nlprob = __construct_nlproblem(cache, vec(cache.y₀))
+    nlprob = __construct_nlproblem(cache, vec(cache.y₀), copy(cache.y₀))
     nlsolve_alg = __concrete_nonlinearsolve_algorithm(nlprob, cache.alg.nlsolve)
     sol_nlprob = __solve(
         nlprob, nlsolve_alg; abstol, kwargs..., nlsolve_kwargs..., alias_u0 = true)
@@ -402,9 +402,11 @@ end
 
 # Constructing the Nonlinear Problem
 function __construct_nlproblem(cache::Union{FIRKCacheNested{iip}, FIRKCacheExpand{iip}},
-        y::AbstractVector) where {iip}
+        y::AbstractVector, y₀::AbstractVectorOfArray) where {iip}
     pt = cache.problem_type
 
+    eval_sol = EvalSol(__restructure_sol(y₀.u, cache.in_size), cache.mesh, cache)
+
     loss_bc = if iip
         @closure (du, u, p) -> __firk_loss_bc!(
             du, u, p, pt, cache.bc, cache.y, cache.mesh, cache)
@@ -422,9 +424,10 @@ function __construct_nlproblem(cache::Union{FIRKCacheNested{iip}, FIRKCacheExpan
 
     loss = if iip
         @closure (du, u, p) -> __firk_loss!(
-            du, u, p, cache.y, pt, cache.bc, cache.residual, cache.mesh, cache)
+            du, u, p, cache.y, pt, cache.bc, cache.residual, cache.mesh, cache, eval_sol)
     else
-        @closure (u, p) -> __firk_loss(u, p, cache.y, pt, cache.bc, cache.mesh, cache)
+        @closure (u, p) -> __firk_loss(
+            u, p, cache.y, pt, cache.bc, cache.mesh, cache, eval_sol)
     end
 
     return __construct_nlproblem(cache, y, loss_bc, loss_collocation, loss, pt)
@@ -658,19 +661,19 @@ function __construct_nlproblem(
     return __internal_nlsolve_problem(cache.prob, resid_prototype, y, nlf, y, cache.p)
 end
 
-@views function __firk_loss!(
-        resid, u, p, y, pt::StandardBVProblem, bc!::BC, residual, mesh, cache) where {BC}
+@views function __firk_loss!(resid, u, p, y, pt::StandardBVProblem, bc!::BC,
+        residual, mesh, cache, eval_sol) where {BC}
     y_ = recursive_unflatten!(y, u)
     resids = [get_tmp(r, u) for r in residual]
-    soly_ = VectorOfArray(y_)
-    eval_bc_residual!(resids[1], pt, bc!, soly_, p, mesh)
     Φ!(resids[2:end], cache, y_, u, p)
+    eval_sol.u[1:end] .= y_
+    eval_bc_residual!(resids[1], pt, bc!, eval_sol, p, mesh)
     recursive_flatten!(resid, resids)
     return nothing
 end
 
 @views function __firk_loss!(resid, u, p, y, pt::TwoPointBVProblem, bc!::Tuple{BC1, BC2},
-        residual, mesh, cache) where {BC1, BC2}
+        residual, mesh, cache, _) where {BC1, BC2}
     y_ = recursive_unflatten!(y, u)
     soly_ = VectorOfArray(y_)
     resids = [get_tmp(r, u) for r in residual]
@@ -682,16 +685,17 @@ end
     return nothing
 end
 
-@views function __firk_loss(u, p, y, pt::StandardBVProblem, bc::BC, mesh, cache) where {BC}
+@views function __firk_loss(
+        u, p, y, pt::StandardBVProblem, bc::BC, mesh, cache, eval_sol) where {BC}
     y_ = recursive_unflatten!(y, u)
-    soly_ = VectorOfArray(y_)
-    resid_bc = eval_bc_residual(pt, bc, soly_, p, mesh)
+    eval_sol.u[1:end] .= y_
+    resid_bc = eval_bc_residual(pt, bc, eval_sol, p, mesh)
     resid_co = Φ(cache, y_, u, p)
     return vcat(resid_bc, mapreduce(vec, vcat, resid_co))
 end
 
-@views function __firk_loss(
-        u, p, y, pt::TwoPointBVProblem, bc::Tuple{BC1, BC2}, mesh, cache) where {BC1, BC2}
+@views function __firk_loss(u, p, y, pt::TwoPointBVProblem, bc::Tuple{BC1, BC2},
+        mesh, cache, _) where {BC1, BC2}
     y_ = recursive_unflatten!(y, u)
     soly_ = VectorOfArray(y_)
     resid_bca, resid_bcb = eval_bc_residual(pt, bc, soly_, p, mesh)
@@ -702,16 +706,16 @@ end
 @views function __firk_loss_bc!(resid, u, p, pt, bc!::BC, y, mesh,
         cache::Union{FIRKCacheNested, FIRKCacheExpand}) where {BC}
     y_ = recursive_unflatten!(y, u)
-    soly_ = VectorOfArray(y_)
-    eval_bc_residual!(resid, pt, bc!, soly_, p, mesh)
+    eval_sol = EvalSol(__restructure_sol(y_, cache.in_size), mesh, cache)
+    eval_bc_residual!(resid, pt, bc!, eval_sol, p, mesh)
     return nothing
 end
 
 @views function __firk_loss_bc(u, p, pt, bc!::BC, y, mesh,
         cache::Union{FIRKCacheNested, FIRKCacheExpand}) where {BC}
     y_ = recursive_unflatten!(y, u)
-    soly_ = VectorOfArray(y_)
-    return eval_bc_residual(pt, bc!, soly_, p, mesh)
+    eval_sol = EvalSol(__restructure_sol(y_, cache.in_size), mesh, cache)
+    return eval_bc_residual(pt, bc!, eval_sol, p, mesh)
 end
 
 @views function __firk_loss_collocation!(resid, u, p, y, mesh, residual, cache)

lib/BoundaryValueDiffEqFIRK/src/interpolation.jl

@@ -127,3 +127,97 @@ end
     cache.mesh, u, cache)
 @inline __build_interpolation(cache::FIRKCacheNested, u::AbstractVector) = FIRKNestedInterpolation(
     cache.mesh, u, cache)
+
+# Intermidiate solution for evaluating boundry conditions
+# basically simplified version of the interpolation for FIRK
+# Expanded FIRK
+function (s::EvalSol{C})(tval::Number) where {C <: FIRKCacheExpand}
+    (; t, u, cache) = s
+    (; f, alg, ITU, p) = cache
+    (; q_coeff) = ITU
+    stage = alg_stage(alg)
+    # Quick handle for the case where tval is at the boundary
+    (tval == t[1]) && return first(u)
+    (tval == t[end]) && return last(u)
+    K = __similar(first(u), length(first(u)), stage)
+    j = interval(t, tval)
+    ctr_y = (j - 1) * (stage + 1) + 1
+
+    yᵢ = u[ctr_y]
+    yᵢ₊₁ = u[ctr_y + stage + 1]
+
+    if SciMLBase.isinplace(cache.prob)
+        dyᵢ = similar(yᵢ)
+        dyᵢ₊₁ = similar(yᵢ₊₁)
+
+        f(dyᵢ, yᵢ, p, t[j])
+        f(dyᵢ₊₁, yᵢ₊₁, p, t[j + 1])
+    else
+        dyᵢ = f(yᵢ, p, t[j])
+        dyᵢ₊₁ = f(yᵢ₊₁, p, t[j + 1])
+    end
+
+    # Load interpolation residual
+    for jj in 1:stage
+        K[:, jj] = u[ctr_y + jj]
+    end
+    h = t[j + 1] - t[j]
+    τ = tval - t[j]
+
+    z₁, z₁′ = eval_q(yᵢ, 0.5, h, q_coeff, K) # Evaluate q(x) at midpoints
+    S_coeffs = get_S_coeffs(h, yᵢ, yᵢ₊₁, z₁, dyᵢ, dyᵢ₊₁, z₁′)
+
+    z = similar(yᵢ)
+
+    S_interpolate!(z, τ, S_coeffs)
+    return z
+end
+
+nodual_value(x) = x
+nodual_value(x::Dual) = ForwardDiff.value(x)
+nodual_value(x::AbstractArray{<:Dual}) = map(ForwardDiff.value, x)
+
+# Nested FIRK
+function (s::EvalSol{C})(tval::Number) where {C <: FIRKCacheNested}
+    (; t, u, cache) = s
+    (; f, nest_prob, nest_tol, alg, mesh_dt, p, ITU) = cache
+    (; q_coeff) = ITU
+    stage = alg_stage(alg)
+    # Quick handle for the case where tval is at the boundary
+    (tval == t[1]) && return first(u)
+    (tval == t[end]) && return last(u)
+    j = interval(t, tval)
+    h = t[j + 1] - t[j]
+    τ = tval - t[j]
+
+    nest_nlsolve_alg = __concrete_nonlinearsolve_algorithm(nest_prob, alg.nlsolve)
+    nestprob_p = zeros(cache.M + 2)
+
+    yᵢ = u[j]
+    yᵢ₊₁ = u[j + 1]
+
+    if SciMLBase.isinplace(cache.prob)
+        dyᵢ = similar(yᵢ)
+        dyᵢ₊₁ = similar(yᵢ₊₁)
+
+        f(dyᵢ, yᵢ, p, t[j])
+        f(dyᵢ₊₁, yᵢ₊₁, p, t[j + 1])
+    else
+        dyᵢ = f(yᵢ, p, t[j])
+        dyᵢ₊₁ = f(yᵢ₊₁, p, t[j + 1])
+    end
+
+    nestprob_p[1] = t[j]
+    nestprob_p[2] = mesh_dt[j]
+    nestprob_p[3:end] .= nodual_value(yᵢ)
+
+    _nestprob = remake(nest_prob, p = nestprob_p)
+    nestsol = __solve(_nestprob, nest_nlsolve_alg; abstol = nest_tol)
+    K = nestsol.u
+
+    z₁, z₁′ = eval_q(yᵢ, 0.5, h, q_coeff, K) # Evaluate q(x) at midpoints
+    S_coeffs = get_S_coeffs(h, yᵢ, yᵢ₊₁, z₁, dyᵢ, dyᵢ₊₁, z₁′)
+    z = similar(yᵢ)
+    S_interpolate!(z, τ, S_coeffs)
+    return z
+end

lib/BoundaryValueDiffEqFIRK/test/expanded/ensemble_tests.jl

@@ -7,8 +7,8 @@
     end
 
     function bc!(residual, u, p, t)
-        residual[1] = u[:, 1][1] - 1.0
-        residual[2] = u[:, end][1]
+        residual[1] = u(0.0)[1] - 1.0
+        residual[2] = u(1.0)[1]
     end
 
     prob_func(prob, i, repeat) = remake(prob, p = [rand()])