Added RKN methods

.github/workflows/CI.yml

@@ -22,6 +22,7 @@ jobs:
           - AlgConvergence_II
           - AlgConvergence_III
           - Downstream
+          - Symplectic
           - Extrapolation
           - StabilizedRK
           - StabilizedIRK

lib/OrdinaryDiffEqRKN/Project.toml

@@ -0,0 +1,23 @@
+name = "OrdinaryDiffEqRKN"
+uuid = "af6ede74-add8-4cfd-b1df-9a4dbb109d7a"
+authors = ["ParamThakkar123 <[email protected]>"]
+version = "1.0.0"
+
+[deps]
+FastBroadcast = "7034ab61-46d4-4ed7-9d0f-46aef9175898"
+MuladdMacro = "46d2c3a1-f734-5fdb-9937-b9b9aeba4221"
+OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
+Polyester = "f517fe37-dbe3-4b94-8317-1923a5111588"
+RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
+
+[compat]
+julia = "1.10"
+
+[extras]
+DiffEqDevTools = "f3b72e0c-5b89-59e1-b016-84e28bfd966d"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[targets]
+test = ["DiffEqDevTools", "Random", "SafeTestsets", "Test"]

lib/OrdinaryDiffEqRKN/src/OrdinaryDiffEqRKN.jl

@@ -0,0 +1,30 @@
+module OrdinaryDiffEqRKN
+
+import OrdinaryDiffEq: alg_order, calculate_residuals!,
+                       initialize!, perform_step!, @unpack, unwrap_alg,
+                       calculate_residuals, alg_extrapolates,
+                       OrdinaryDiffEqAlgorithm,
+                       OrdinaryDiffEqMutableCache, OrdinaryDiffEqConstantCache,
+                       OrdinaryDiffEqAdaptivePartitionedAlgorithm,
+                       OrdinaryDiffEqPartitionedAlgorithm,
+                       OrdinaryDiffEqAdaptiveAlgorithm, CompiledFloats, uses_uprev,
+                       alg_cache, _vec, _reshape, @cache, isfsal, full_cache,
+                       constvalue, _unwrap_val, du_alias_or_new, _ode_interpolant,
+                       trivial_limiter!, _ode_interpolant!, _ode_addsteps!
+using DiffEqBase, FastBroadcast, Polyester, MuladdMacro, RecursiveArrayTools
+using DiffEqBase: @def, @tight_loop_macros
+
+include("algorithms.jl")
+include("alg_utils.jl")
+include("rkn_tableaus.jl")
+include("rkn_caches.jl")
+include("interp_func.jl")
+include("interpolants.jl")
+include("rkn_perform_step.jl")
+
+export Nystrom4, FineRKN4, FineRKN5, Nystrom4VelocityIndependent,
+       Nystrom5VelocityIndependent,
+       IRKN3, IRKN4, DPRKN4, DPRKN5, DPRKN6, DPRKN6FM, DPRKN8, DPRKN12, ERKN4, ERKN5, ERKN7,
+       RKN4
+
+end

lib/OrdinaryDiffEqRKN/src/alg_utils.jl

@@ -0,0 +1,20 @@
+alg_extrapolates(alg::IRKN3) = true
+alg_extrapolates(alg::IRKN4) = true
+
+alg_order(alg::IRKN3) = 3
+alg_order(alg::Nystrom4) = 4
+alg_order(alg::FineRKN4) = 4
+alg_order(alg::FineRKN5) = 5
+alg_order(alg::Nystrom4VelocityIndependent) = 4
+alg_order(alg::IRKN4) = 4
+alg_order(alg::Nystrom5VelocityIndependent) = 5
+alg_order(alg::DPRKN4) = 4
+alg_order(alg::DPRKN5) = 5
+alg_order(alg::DPRKN6) = 6
+alg_order(alg::DPRKN6FM) = 6
+alg_order(alg::DPRKN8) = 8
+alg_order(alg::DPRKN12) = 12
+alg_order(alg::ERKN4) = 4
+alg_order(alg::ERKN5) = 5
+alg_order(alg::ERKN7) = 7
+alg_order(alg::RKN4) = 4