Merge pull request #200 from ErikQQY/qqy/nonadaptive_interpolation

Fix non-adaptive interpolation

Project.toml

@@ -1,6 +1,6 @@
 name = "BoundaryValueDiffEq"
 uuid = "764a87c0-6b3e-53db-9096-fe964310641d"
-version = "5.9.0"
+version = "5.9.1"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"

src/solve/mirk.jl

@@ -56,8 +56,7 @@ function SciMLBase.__init(prob::BVProblem, alg::AbstractMIRK; dt = 0.0,
 
     k_discrete = [__maybe_allocate_diffcache(similar(X, N, stage), chunksize, alg.jac_alg)
                   for _ in 1:Nig]
-    k_interp = [similar(X, ifelse(adaptive, N, 0), ifelse(adaptive, ITU.s_star - stage, 0))
-                for _ in 1:Nig]
+    k_interp = [similar(X, N, ITU.s_star - stage) for _ in 1:Nig]
 
     bcresid_prototype, resid₁_size = __get_bcresid_prototype(prob.problem_type, prob, X)
 
@@ -72,7 +71,7 @@ function SciMLBase.__init(prob::BVProblem, alg::AbstractMIRK; dt = 0.0,
     end
 
     defect = [similar(X, ifelse(adaptive, N, 0)) for _ in 1:Nig]
-    new_stages = [similar(X, ifelse(adaptive, N, 0)) for _ in 1:Nig]
+    new_stages = [similar(X, N) for _ in 1:Nig]
 
     # Transform the functions to handle non-vector inputs
     bcresid_prototype = __vec(bcresid_prototype)

test/mirk/mirk_basic_tests.jl

@@ -175,13 +175,21 @@ end
         @eval mirk_solver(::Val{$order}) = $(s)()
     end
 
-    @testset "MIRK$order" for order in (2, 3, 4, 5, 6)
+    @testset "Interpolation for adaptive MIRK$order" for order in (2, 3, 4, 5, 6)
         sol = solve(prob_bvp_linear, mirk_solver(Val(order)); dt = 0.001)
         @test sol(0.001)≈[0.998687464, -1.312035941] atol=testTol
         @test sol(0.001; idxs = [1, 2])≈[0.998687464, -1.312035941] atol=testTol
         @test sol(0.001; idxs = 1)≈0.998687464 atol=testTol
         @test sol(0.001; idxs = 2)≈-1.312035941 atol=testTol
     end
+
+    @testset "Interpolation for non-adaptive MIRK$order" for order in (2, 3, 4, 5, 6)
+        sol = solve(prob_bvp_linear, mirk_solver(Val(order)); dt = 0.001, adaptive=false)
+        @test_nowarn sol(0.01)
+        @test_nowarn sol(0.01; idxs = [1, 2])
+        @test_nowarn sol(0.01; idxs = 1)
+        @test_nowarn sol(0.01; idxs = 2)
+    end
 end
 
 @testitem "Swirling Flow III" begin