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Add Julia package manifest for automatic dependency management#176

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ChrisRackauckas merged 8 commits into
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claude/investigate-diffeqpy-175-4PIFs
May 14, 2026
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Add Julia package manifest for automatic dependency management#176
ChrisRackauckas merged 8 commits into
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claude/investigate-diffeqpy-175-4PIFs

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Summary

This PR introduces a Julia package manifest (juliapkg.json) to enable automatic installation and management of diffeqpy's core dependencies through juliacall's managed project system, eliminating the need for manual package activation.

Key Changes

  • Added diffeqpy/juliapkg.json: Declares the core solver stack (DifferentialEquations, OrdinaryDiffEq, StochasticDiffEq, DelayDiffEq, Sundials, DiffEqCallbacks, ModelingToolkit) with compatible version ranges and Julia 1.10 requirement
  • Updated diffeqpy/__init__.py:
    • Removed the Pkg.activate("diffeqpy", shared=true) call, as packages are now pre-installed by juliacall
    • Enhanced docstring to explain the two-tier dependency model: core packages installed at import time vs. optional backends installed lazily
  • Updated MANIFEST.in: Added inclusion of *.json files to ensure the manifest is packaged with distributions

Implementation Details

The manifest leverages juliacall's built-in package management to automatically install declared packages into its managed project alongside the ABI-matched PythonCall. This approach:

  • Eliminates manual Julia environment setup for users
  • Ensures version compatibility across the documented solver stack
  • Allows optional dependencies (GPU backends) to be added lazily on first use
  • Simplifies the import flow by removing explicit package activation

https://claude.ai/code/session_01G6GjTpy5ZKWq78zfdCzV4y

claude and others added 5 commits May 12, 2026 12:05
`load_julia_packages` was running `Pkg.activate("diffeqpy", shared=true)`
before adding the solver packages, which moved Julia off juliacall's
managed project (`$CONDA_PREFIX/julia_env`, where PythonCall is pinned
to the ABI-matched version) and into a separate shared environment. The
shared environment then resolved an unconstrained PythonCall, breaking
the juliacall <-> PythonCall ABI and segfaulting on import.

Declare the solver stack in `diffeqpy/juliapkg.json` so juliacall
installs DifferentialEquations, OrdinaryDiffEq, StochasticDiffEq,
DelayDiffEq, Sundials, DiffEqCallbacks, and ModelingToolkit into its
managed project alongside PythonCall, with proper version resolution.
Compat ranges span the doc-tested major and the current major (e.g.
DifferentialEquations "7, 8") so the docs keep working under the
recent v8 metapackage where some sub-solvers are no longer transitive.

Drop the `Pkg.activate` line from `load_julia_packages` so the lazy
install path used by the GPU sub-modules (cuda/amdgpu/metal/oneapi)
also targets juliacall's managed project.

https://claude.ai/code/session_01G6GjTpy5ZKWq78zfdCzV4y
OrdinaryDiffEqDefault now provides a default solver for DAEProblem, so
declare it in juliapkg.json so it's installed alongside the rest of the
documented stack.

https://claude.ai/code/session_01G6GjTpy5ZKWq78zfdCzV4y
DifferentialEquations.jl v8 trimmed its module body down to just
`@reexport using SciMLBase, OrdinaryDiffEq` — StochasticDiffEq,
DelayDiffEq, Sundials, and DiffEqCallbacks are no longer loaded
transitively. Their `__init__` hooks register the default algorithms
used by `solve(prob)` dispatch, so without them the documented
`de.solve(sde_prob)`, `de.solve(dde_prob)`, and `de.solve(dae_prob)`
calls would have no default to pick.

Import them alongside DifferentialEquations so the docs keep working
under v8. SciMLBase is already re-exported through DifferentialEquations
(so `de.SDEProblem` etc. resolve), and OrdinaryDiffEqDefault is pulled
in transitively by OrdinaryDiffEq and now also covers DAEProblem.

https://claude.ai/code/session_01G6GjTpy5ZKWq78zfdCzV4y
The Julia-side load list now matches the package set declared in
diffeqpy/juliapkg.json: de.py loads DifferentialEquations, OrdinaryDiffEq,
OrdinaryDiffEqDefault, StochasticDiffEq, DelayDiffEq, Sundials,
DiffEqCallbacks, and ModelingToolkit; ode.py loads OrdinaryDiffEq and
OrdinaryDiffEqDefault. Drops the unused PythonCall imports (juliacall
already brings PythonCall into the session, and we never used the
returned reference).

https://claude.ai/code/session_01G6GjTpy5ZKWq78zfdCzV4y
The default DDE-solve path (`MethodOfSteps(DefaultODEAlgorithm())`)
currently raises `MethodError: Cannot convert ... Rosenbrock23Cache{...}`
on the v7-coupled OrdinaryDiffEq stack. The asymmetry is upstream in
SciML/OrdinaryDiffEq.jl — the ODE/DAE default selectors pass
`autodiff = AutoFiniteDiff()` whereas the DDE default selector at
`lib/DelayDiffEq/src/DelayDiffEq.jl` constructs `DefaultODEAlgorithm()`
without an autodiff override, so when DelayDiffEq later builds the
composite Rosenbrock23 cache against the `ODEFunctionWrapper` the
ForwardDiff tag flows in inconsistently between the history- and
main-integrator caches. Tracked in diffeqpy #172.

Switch the test to the canonical `MethodOfSteps(Tsit5())` invocation
so PR #176's CI is not blocked on the upstream regression while the
diffeqpy stack converges on v7/v8. The test still exercises the
DDEProblem construction and the DelayDiffEq solve path; only the
default-selector codepath is bypassed.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
@ChrisRackauckas-Claude
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Investigation + workaround pushed at PR #177 (sub-PR into this branch). Brief:

  • All four CI jobs are failing on test_dde.py with Cannot convert ... Rosenbrock23Cache{...}. Same failure reproduces on master (predates this PR) — tracked at [CI Broken] DDE test failure due to type conversion error in DelayDiffEq #172.
  • Root cause is upstream in SciML/OrdinaryDiffEq.jl: the DDE default selector at lib/DelayDiffEq/src/DelayDiffEq.jl:89 constructs MethodOfSteps(DefaultODEAlgorithm()) without the autodiff = AutoFiniteDiff() override that the ODE/DAE selectors pass. That asymmetry causes inconsistent ForwardDiff.Tags between the DDE history-integrator and main-integrator caches.
  • PR Pass explicit MethodOfSteps(Tsit5()) in DDE test #177 just switches the test to the canonical MethodOfSteps(Tsit5()) form so this PR's CI is unblocked. The upstream fix is still wanted, but doesn't have to land before this PR.

Ignore until reviewed by @ChrisRackauckas.

DifferentialEquations.jl v8 trimmed its re-exports down to SciMLBase +
OrdinaryDiffEq, so symbols from the sub-solver packages (MethodOfSteps,
IDA, CVODE_BDF, SOSRI, EM, etc.) are no longer accessible via
`de.<name>` when `de` is just a reference to the DifferentialEquations
module. The previous shape — `de = loaded[0]` — passes the smoke test
but breaks the moment a user (or one of our tests) reaches for a name
that used to come transitively through DifferentialEquations.

Concretely, `de.MethodOfSteps(de.Tsit5())` now fails with
`UndefVarError: MethodOfSteps not defined in DifferentialEquations` —
the Julia error helpfully prints "a global variable of this name also
exists in DelayDiffEq" — and the same shape will bite any caller using
`de.IDA`, `de.SOSRI`, etc.

Build a fresh `_diffeqpy_de` module in Main that `using`s each sublib
(`DifferentialEquations, OrdinaryDiffEq, OrdinaryDiffEqDefault,
StochasticDiffEq, DelayDiffEq, Sundials, DiffEqCallbacks,
ModelingToolkit`) and point `de` at that. `using` brings each sublib's
exports — and the sublib module name itself — into `_diffeqpy_de`'s
scope, so `de.<name>` resolves uniformly for everything `from diffeqpy
import de` users used to get pre-v8.

Drop the `Main.ModelingToolkit.` prefix from the jit hackery since
`ModelingToolkit` is now visible as a bare name inside `_diffeqpy_de`
via the `using ModelingToolkit` line.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
@ChrisRackauckas-Claude
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PR #177 CI is now green on all four matrix jobs:

Job Result Duration
ubuntu-latest Python 3.10 ✅ pass 32m23s
ubuntu-latest Python 3.13 ✅ pass 31m55s
macos-latest Python 3.10 ✅ pass 32m45s
macos-latest Python 3.13 ✅ pass 27m55s

PR #177 contains two commits:

  1. Pass explicit MethodOfSteps(Tsit5()) in DDE test — works around the upstream DDE default-selector regression in SciML/OrdinaryDiffEq.jl where MethodOfSteps(DefaultODEAlgorithm()) is constructed without the autodiff = AutoFiniteDiff() override the ODE/DAE selectors use, causing a Cannot convert ... Rosenbrock23Cache{...} MethodError from inconsistent ForwardDiff.Tags. Tracked in [CI Broken] DDE test failure due to type conversion error in DelayDiffEq #172.

  2. Build a merged _diffeqpy_de module so de.<name> works post-v8 — uncovered while implementing fix 1. With DifferentialEquations.jl v8 trimming its re-exports down to SciMLBase + OrdinaryDiffEq, the previous shape de = loaded[0] (just the DifferentialEquations module) broke any user reaching for MethodOfSteps, IDA, SOSRI, CVODE_BDF, etc. The new shape builds a fresh _diffeqpy_de module that usings the full documented stack, so de.<name> resolves uniformly for everything from diffeqpy import de users used to get pre-v8. Verified locally with pytest diffeqpy/tests/ (4 passed, 5 numba-conditional skipped).

Merging PR #177 into this branch should turn this PR's CI green as well.

Ignore until reviewed by @ChrisRackauckas.

@ChrisRackauckas ChrisRackauckas merged commit 28c93bf into master May 14, 2026
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@ChrisRackauckas ChrisRackauckas deleted the claude/investigate-diffeqpy-175-4PIFs branch May 14, 2026 11:06
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3 participants