Issues

• Partial indexed Initial overrides lose explicitly supplied values during split parameter construction

  SciML/ModelingToolkit.jl#5299 · Filter by author ChrisRackauckas-Claude opened on Oct 21, 2026

• DAE residual codegen references an undefined parent array when only selected elements are states

  SciML/ModelingToolkit.jl#5297 · Filter by author ChrisRackauckas-Claude opened on Oct 21, 2026

• Generated function with an inlined linear SCC gives wrong results when called with the same parameter object from several threads

  SciML/ModelingToolkit.jl#5294 · Filter by author baggepinnen opened on Oct 20, 2026

• mtkcompile with inputs: AssertionError last_idx <= idx unless the inputs are given in the order of the parameter buffers

  SciML/ModelingToolkit.jl#5293 · Filter by author baggepinnen opened on Oct 20, 2026

• Initialization fails for an array-return callable parameter bound via bindings (canonicalize_eq! MethodError)

  SciML/ModelingToolkit.jl#5282 · Filter by author ChrisRackauckas-Claude opened on Oct 16, 2026

• inline_linear_sccs: analytical sym_lu divides by (I21 - I11*I32/I31), which is 0 when only I31 is non-zero (NaN in rigid-body Euler equations)

  SciML/ModelingToolkit.jl#5279 · Filter by author mwhincup opened on Oct 15, 2026
  1

• solve(::SteadyStateProblem) throws promotion of types Float64 and ModelingToolkitBase.PleaseImportDynamicQuantities failed when inline_linear_sccs = true inlines a linear SCC as an array solve: the observed code references the independent variable t

  SciML/ModelingToolkit.jl#5273 · Filter by author jesse-gohl opened on Oct 13, 2026

• ODEProblem construction spends most of its time evaluating guesses for a LinearInitializationProblem; reported not to finish on macOS

  SciML/ModelingToolkit.jl#5272 · Filter by author baggepinnen opened on Oct 13, 2026

• solve(::SteadyStateProblem) throws UndefVarError: hˍt when the model has implicit derivative equations: derivative unknowns leak into the lowered problem's initialization

  SciML/ModelingToolkit.jl#5270 · Filter by author jesse-gohl opened on Oct 12, 2026
  2

• A binding whose value has the wrong shape for its array parameter fails late, with an error that does not name the parameter

  SciML/ModelingToolkit.jl#5259 · Filter by author pankgeorg opened on Oct 7, 2026

• generate_control_function does not pass options of the structural simplification (reassemble_alg) to mtkcompile

  SciML/ModelingToolkit.jl#5255 · Filter by author baggepinnen opened on Oct 4, 2026

• linearize: the input Jacobians are evaluated at the guess of an input that the initialization solves for

  SciML/ModelingToolkit.jl#5224 · Filter by author baggepinnen opened on Sep 29, 2026
  1

• Stream connectors: positivemax drops sq, so outer-connector stream mixing is unweighted

  SciML/ModelingToolkit.jl#5218 · Filter by author ChrisRackauckas-Claude opened on Sep 27, 2026

• Stream connectors: instream_rt uses the wrong sign for outer-connector weights (NaN in hierarchical connects)

  SciML/ModelingToolkit.jl#5217 · Filter by author ChrisRackauckas-Claude opened on Sep 27, 2026

• InvalidKeyError / MissingParametersError are unreachable: bad keys throw TypeError in build_operating_point first (test/problem_validation.jl fails 5/5, not wired in)

  SciML/ModelingToolkit.jl#5216 · Filter by author ChrisRackauckas-Claude opened on Sep 27, 2026

• Tearing picks a pivot that vanishes at t0 (time-dependent constraint coefficient): NaN initial value, no warning

  SciML/ModelingToolkit.jl#5212 · Filter by author ChrisRackauckas-Claude opened on Sep 26, 2026
  4

• Construct AutoDespecialize ODEProblems in the despecialized form (per-model time-to-first-solve)

  SciML/ModelingToolkit.jl#5211 · Filter by author ChrisRackauckas-Claude opened on Sep 26, 2026

• Allow bindings on indexed array parameter keys

  enhancement
  SciML/ModelingToolkit.jl#5210 · Filter by author Fololo opened on Sep 25, 2026
  1

• Clocked discrete events: no reaction at tspan[2] when it falls on a tick — intended contract? Please document (or expose final_affect)

  SciML/ModelingToolkit.jl#5207 · Filter by author pankgeorg opened on Sep 24, 2026
  

• Discrete event on a system with algebraic equations changes a differential state instead of the algebraic variable

  SciML/ModelingToolkit.jl#5200 · Filter by author ChrisRackauckas-Claude opened on Sep 23, 2026
  1

• Cost gradient fails with 'Differentiation of x[1] inside lazy array expressions' when sum(A*x) is nested in the cost (hash-order dependent)

  SciML/ModelingToolkit.jl#5199 · Filter by author ChrisRackauckas-Claude opened on Sep 23, 2026

• Fails to solve SteadyStateProblem

  bug
  SciML/ModelingToolkit.jl#5194 · Filter by author wenflo opened on Sep 23, 2026
  1

• DAEProblem: accept derivative guesses instead of requiring every du0 in op, so MTK initialization can find consistent du0

  SciML/ModelingToolkit.jl#5193 · Filter by author ChrisRackauckas-Claude opened on Sep 23, 2026
  2

• No derivative rule for instream_rt: jac = true fails with Float64(::Num) on multi-source stream connections

  SciML/ModelingToolkit.jl#5192 · Filter by author ChrisRackauckas-Claude opened on Sep 23, 2026
  1

• Initialization fails for residual-form equations over array slices (Differential(t) with independent variable nothing)

  SciML/ModelingToolkit.jl#5188 · Filter by author ChrisRackauckas-Claude opened on Sep 23, 2026
  1