feat: add

Author: vyudu

lib/SimpleImplicitDiscreteSolve/src/alg_utils.jl

@@ -17,3 +17,18 @@ beta1_default(alg::SimpleIDSolve, beta2) = 0
 
 dt_required(alg::SimpleIDSolve) = false
 isdiscretealg(alg::SimpleIDSolve) = true
+
+function DiffEqBase._initialize_dae!(integrator, prob::ImplicitDiscreteProblem,
+        alg::DefaultInit, x::Union{Val{true}, Val{false}})
+    atol = one(eltype(prob.u0)) * 1e-12
+    if SciMLBase.has_initializeprob(prob.f)
+        _initialize_dae!(integrator, prob,
+                         OverrideInit(atol), x)
+    elseif !applicable(_initialize_dae!, integrator, prob,
+        BrownFullBasicInit(atol), x)
+        error("`OrdinaryDiffEqNonlinearSolve` is not loaded, which is required for the default initialization algorithm (`BrownFullBasicInit` or `ShampineCollocationInit`). To solve this problem, either do `using OrdinaryDiffEqNonlinearSolve` or pass `initializealg = CheckInit()` to the `solve` function. This second option requires consistent `u0`.")
+    else
+        _initialize_dae!(integrator, prob,
+            BrownFullBasicInit(atol), x)
+    end
+end

lib/SimpleImplicitDiscreteSolve/test/runtests.jl

@@ -48,3 +48,6 @@ using OrdinaryDiffEqSDIRK
 
     @test isapprox(idsol[end], osol[end], atol = 0.01)
 end
+
+@testset "Solve respects initialization" begin
+end