Skip to content

fix: fix AD through inline linear SCCs #4517

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
AayushSabharwal merged 1 commit into from
May 11, 2026
+26 −1
Merged

fix: fix AD through inline linear SCCs #4517

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion lib/ModelingToolkitBase/src/systems/problem_utils.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -849,7 +849,7 @@ function get_mtkparameters_reconstructor(
initialvals = getters[2](valp)
nonnumerics = getters[5](valp)
if !iszero(diffcache_buffer_idx)
@set! nonnumerics[diffcache_buffer_idx] = DiffCacheAllocatorAPIWrapper{eltype(initialvals)}.(nonnumerics[diffcache_buffer_idx])
@set! nonnumerics[diffcache_buffer_idx] = DiffCacheAllocatorAPIWrapper{ForwardDiff.valtype(eltype(initialvals))}.(nonnumerics[diffcache_buffer_idx])
end
return promote_with_nothing(
promote_type_with_nothing(eltype(tunablevals), initialvals),
Expand Down
25 changes: 25 additions & 0 deletions test/structural_transformation/tearing.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ using SymbolicIndexingInterface
using ModelingToolkit: t_nounits as t, D_nounits as D
import StateSelection
import SymbolicUtils as SU
using ForwardDiff

###
### Nonlinear system
###
Expand Down Expand Up @@ -291,3 +293,26 @@ end
@test Initial(sys.resistor1.v) in Set(ModelingToolkit.get_ps(sys))
@test Initial(sys.resistor2.v) in Set(ModelingToolkit.get_ps(sys))
end

@testset "AD through inline linear SCCs works" begin
reassemble_alg = StructuralTransformations.DefaultReassembleAlgorithm(; inline_linear_sccs = true)
@mtkcompile sys = RCModel() reassemble_alg = reassemble_alg
prob = ODEProblem(sys, [], (0.0, 10.0))
@assert prob.p.nonnumeric[1] isa
Vector{ModelingToolkitBase.DiffCacheAllocatorAPIWrapper{Float64}}
@assert SciMLBase.has_initializeprob(prob.f)

setter = setsym_oop(prob, [sys.R, sys.C])

function loss(x)
new_u0, new_p = setter(prob, x)
new_prob = remake(prob; u0 = new_u0, p = new_p)
sol = solve(new_prob, Tsit5(); abstol = 1.0e-8, reltol = 1.0e-8)
return sol[sys.capacitor.v][end]
end

# Primal works: returns ~0.993
@test_nowarn loss([1.0, 1.0])

@test_nowarn ForwardDiff.gradient(loss, [1.0, 1.0])
end
Loading