From cd532ece939fb4301ebd593f38b79e37bfa932e1 Mon Sep 17 00:00:00 2001
From: jClugstor <jadonclugston@gmail.com>
Date: Mon, 23 Dec 2024 13:22:25 -0500
Subject: [PATCH] add support for DDEAliasSpecifier

---
 Project.toml               |  2 +-
 src/DelayDiffEq.jl         |  1 +
 src/solve.jl               | 39 +++++++++++++++++++++++++++++++++++++-
 test/interface/aliasing.jl | 23 ++++++++++++++++++++++
 4 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 test/interface/aliasing.jl

diff --git a/Project.toml b/Project.toml
index 196f2e8..eba16e6 100644
--- a/Project.toml
+++ b/Project.toml
@@ -35,7 +35,7 @@ OrdinaryDiffEqNonlinearSolve = "1.2.2"
 OrdinaryDiffEqRosenbrock = "1.2.0"
 RecursiveArrayTools = "2, 3"
 Reexport = "0.2, 1.0"
-SciMLBase = "2.68"
+SciMLBase = "2.69"
 SimpleNonlinearSolve = "0.1, 1, 2"
 SimpleUnPack = "1"
 SymbolicIndexingInterface = "0.3.36"
diff --git a/src/DelayDiffEq.jl b/src/DelayDiffEq.jl
index 9ecc323..48b877d 100644
--- a/src/DelayDiffEq.jl
+++ b/src/DelayDiffEq.jl
@@ -25,6 +25,7 @@ using OrdinaryDiffEqNonlinearSolve: NLNewton, NLAnderson, NLFunctional, Abstract
 using OrdinaryDiffEqRosenbrock: RosenbrockMutableCache
 
 import SciMLBase
+using SciMLBase: DDEAliasSpecifier
 
 export Discontinuity, MethodOfSteps
 
diff --git a/src/solve.jl b/src/solve.jl
index ea4f5d0..ce8636e 100644
--- a/src/solve.jl
+++ b/src/solve.jl
@@ -62,6 +62,7 @@ function DiffEqBase.__init(prob::DiffEqBase.AbstractDDEProblem,
         allow_extrapolation = OrdinaryDiffEqCore.alg_extrapolates(alg),
         initialize_integrator = true,
         alias_u0 = false,
+        alias = DDEAliasSpecifier(),
         # keyword arguments for DDEs
         discontinuity_interp_points::Int = 10,
         discontinuity_abstol = eltype(prob.tspan)(1 // Int64(10)^12),
@@ -107,6 +108,42 @@ function DiffEqBase.__init(prob::DiffEqBase.AbstractDDEProblem,
     # unpack problem
     @unpack f, u0, h, tspan, p, neutral, constant_lags, dependent_lags = prob
 
+    use_old_kwargs = haskey(kwargs, :alias_u0)
+
+    if haskey(kwargs, :alias_u0)
+        aliases = DDEAliasSpecifier()
+        message = "`alias_u0` keyword argument is deprecated, to set `alias_u0`,
+        please use an ODEAliasSpecifier, e.g. `solve(prob, alias = ODEAliasSpecifier(alias_u0 = true))"
+        Base.depwarn(message, :init)
+        Base.depwarn(message, :solve)
+        aliases = DDEAliasSpecifier(alias_u0 = values(kwargs).alias_u0)
+    else
+        # If alias isa Bool, all fields of ODEAliases set to alias
+        if alias isa Bool
+            aliases = DDEAliasSpecifier(alias = alias)
+        elseif alias isa DDEAliasSpecifier
+            aliases = alias
+        end
+    end
+
+    if isnothing(aliases.alias_f) || aliases.alias_f
+        f = f
+    else
+        f = deepcopy(f)
+    end
+
+    if isnothing(aliases.alias_p) || aliases.alias_p
+        p = p
+    else
+        p = recursivecopy(p)
+    end
+
+    if !isnothing(aliases.alias_u0) && aliases.alias_u0
+        u = prob.u0
+    else
+        u = recursivecopy(prob.u0)
+    end
+
     # determine type and direction of time
     tType = eltype(tspan)
     t0 = first(tspan)
@@ -131,7 +168,7 @@ function DiffEqBase.__init(prob::DiffEqBase.AbstractDDEProblem,
 
     # get states (possibly different from the ODE integrator!)
     u, uprev, uprev2 = u_uprev_uprev2(u0, alg;
-        alias_u0 = alias_u0,
+        alias_u0 = aliases.alias_u0,
         adaptive = adaptive,
         allow_extrapolation = allow_extrapolation,
         calck = calck)
diff --git a/test/interface/aliasing.jl b/test/interface/aliasing.jl
new file mode 100644
index 0000000..9a2a3fa
--- /dev/null
+++ b/test/interface/aliasing.jl
@@ -0,0 +1,23 @@
+using DelayDiffEq, DDEProblemLibrary
+
+# For now, testing if the old keyword works the same as the new alias keyword
+prob_ip = prob_dde_constant_1delay_ip
+prob_scalar = prob_dde_constant_1delay_scalar
+ts = 0:0.1:10
+
+noreuse = NLNewton(fast_convergence_cutoff = 0)
+
+const working_algs = [ImplicitMidpoint(), SSPSDIRK2(), KenCarp5(nlsolve = noreuse),
+    ImplicitEuler(nlsolve = noreuse), Trapezoid(nlsolve = noreuse),
+    TRBDF2(nlsolve = noreuse)]
+
+@testset "Algorithm $(nameof(typeof(alg)))" for alg in working_algs
+    println(nameof(typeof(alg)))
+
+    stepsalg = MethodOfSteps(alg)
+    sol_new_alias = solve(prob_ip, stepsalg; dt = 0.1, alias = DDEAliasSpecifier(alias_u0 = true))
+    sol_old_alias = solve(
+        prob_ip, stepsalg; dt = 0.1, alias = alias_u0 = true)
+
+    @test sol_new_alias == sol_old_alias
+end
\ No newline at end of file