# \#sciml

**URL:** https://discourse.julialang.org/tag/sciml/435.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

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## [Understanding jump model preparation cost](https://discourse.julialang.org/t/understanding-jump-model-preparation-cost/138472)

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**Author:** [@lmshk](https://discourse.julialang.org/u/lmshk)\
**Replies:** 19\
**Last updated:** [September 23, 2026, 1:32pm UTC](https://discourse.julialang.org/t/understanding-jump-model-preparation-cost/138472 "2026-09-23T13:32:43Z")

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I am using Catalyst.jl to make JumpProblems of around 160k species and a fairly sparse interaction structure that includes what JumpProcesses.jl calls “constant-rate jump” (CRJ) reactions. This works, but JumpProblem con…

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## [Compiler mis-recognizes contiguous reinterpreted matrices?](https://discourse.julialang.org/t/compiler-mis-recognizes-contiguous-reinterpreted-matrices/138979)

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**Author:** [@bremez](https://discourse.julialang.org/u/bremez)\
**Replies:** 11\
**Last updated:** [August 25, 2026, 2:02pm UTC](https://discourse.julialang.org/t/compiler-mis-recognizes-contiguous-reinterpreted-matrices/138979 "2026-08-25T14:02:33Z")

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I am implementing an ODE to use with OrdinaryDiffEq. I am simultaneously evolving in time multiple quantities, which are combinations of vectors and matrices, some real and some complex. The approach I took has been to g…

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## [Warning in SciMLBase about ContinousClock](https://discourse.julialang.org/t/warning-in-scimlbase-about-continousclock/138534)

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**Author:** [@c-nicomar](https://discourse.julialang.org/u/c-nicomar)\
**Replies:** 5\
**Last updated:** [July 31, 2026, 5:57pm UTC](https://discourse.julialang.org/t/warning-in-scimlbase-about-continousclock/138534 "2026-07-31T17:57:42Z")

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During precompilation I get this warning. How could I avoid this? I have this version v2.155.1 SciMLBase │ ┌ Warning: the bare singleton variant syntax \`ContinuousClock\` is deprecated, write \`ContinuousClock()\` instead…

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## [Making a Universal Differential Equation Faster](https://discourse.julialang.org/t/making-a-universal-differential-equation-faster/137829)

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**Author:** [@Ashima\_Kalathingal](https://discourse.julialang.org/u/Ashima_Kalathingal)\
**Replies:** 1\
**Last updated:** [June 28, 2026, 1:57am UTC](https://discourse.julialang.org/t/making-a-universal-differential-equation-faster/137829 "2026-06-28T01:57:32Z")

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I have a two-state ODE, one of which is embedded in a neural network, making it a UDE. I am using 9 datasets for training, resulting in 9 distinct ODEs. prob1 = ODEProblem(UDE\_model1!,\[SOC0\_1, T∞1\],(time1\[1\],time1\[end\])…

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## [SciML: Issues using \`GaussAdjoint\` on an \`EnsembleProblem\` with callbacks](https://discourse.julialang.org/t/sciml-issues-using-gaussadjoint-on-an-ensembleproblem-with-callbacks/137503)

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**Author:** [@LucasGrasso](https://discourse.julialang.org/u/LucasGrasso)\
**Replies:** 11\
**Last updated:** [June 21, 2026, 8:30pm UTC](https://discourse.julialang.org/t/sciml-issues-using-gaussadjoint-on-an-ensembleproblem-with-callbacks/137503 "2026-06-21T20:30:04Z")

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Hello there, I am rather new to Julia, and I am trying to implement a Neural ODE model that relies on event callbacks to terminate integration. I am using the GaussAdjoint, given that it supports callbacks and that it w…

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## [ModelingToolkit V11 Library Split and Licensing, Community Feedback Requested](https://discourse.julialang.org/t/modelingtoolkit-v11-library-split-and-licensing-community-feedback-requested/134396)

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**Author:** [@isaacsas](https://discourse.julialang.org/u/isaacsas)\
**Replies:** 137\
**Last updated:** [May 22, 2026, 4:01pm UTC](https://discourse.julialang.org/t/modelingtoolkit-v11-library-split-and-licensing-community-feedback-requested/134396 "2026-05-22T16:01:21Z")

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Dear MTK Community, I am posting today in my role as a member of the SciML Steering Council about a decision the council has been discussing regarding the future of ModelingToolkit (MTK). As this decision impacts the MT…

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## [How to update from the archived \`StochasticDelayDiffEq.jl\`?](https://discourse.julialang.org/t/how-to-update-from-the-archived-stochasticdelaydiffeq-jl/137041)

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**Author:** [@scheidan1](https://discourse.julialang.org/u/scheidan1)\
**Replies:** 8\
**Last updated:** [May 12, 2026, 10:41am UTC](https://discourse.julialang.org/t/how-to-update-from-the-archived-stochasticdelaydiffeq-jl/137041 "2026-05-12T10:41:23Z")

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Hello I’m try to modernize a package that is based on the now archived StochasticDelayDiffEq.jl. As described here the SciML packages have been reorganized. The migration path from StochasticDelayDiffEq.jl is not descr…

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## [DiffEqBase.jl moved in March without much notification to the community using it](https://discourse.julialang.org/t/diffeqbase-jl-moved-in-march-without-much-notification-to-the-community-using-it/136781)

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**Author:** [@bparbhu](https://discourse.julialang.org/u/bparbhu)\
**Replies:** 9\
**Last updated:** [April 21, 2026, 6:32pm UTC](https://discourse.julialang.org/t/diffeqbase-jl-moved-in-march-without-much-notification-to-the-community-using-it/136781 "2026-04-21T18:32:36Z")

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Hi all, I haven’t seen a post about how sunsetting works in SciML. Does anyone know if there’s been any communication about sunsetting DiffEqBase.jl GitHub - SciML/DiffEqBase.jl: The lightweight Base library for shared…

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## [\[GSoC '26\] The Illusion of Uniformity: Non-Uniform Grids & Zero-Overhead Dispatch in MOL.jl](https://discourse.julialang.org/t/gsoc-26-the-illusion-of-uniformity-non-uniform-grids-zero-overhead-dispatch-in-mol-jl/136639)

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**Author:** [@Utku\_Yilmaz](https://discourse.julialang.org/u/Utku_Yilmaz)\
**Replies:** 0\
**Last updated:** [April 9, 2026, 10:00am UTC](https://discourse.julialang.org/t/gsoc-26-the-illusion-of-uniformity-non-uniform-grids-zero-overhead-dispatch-in-mol-jl/136639 "2026-04-09T10:00:18Z")

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Hi everyone, As part of my GSoC 2026 prep for MethodOfLines.jl, I just published a short devlog on bringing non-uniform grid support to high-order schemes like WENO. My post, “The Illusion of Uniformity,” outlines the a…

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## [Some update broke our project - how to fix faster](https://discourse.julialang.org/t/some-update-broke-our-project-how-to-fix-faster/136551)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [April 4, 2026, 10:46am UTC](https://discourse.julialang.org/t/some-update-broke-our-project-how-to-fix-faster/136551 "2026-04-04T10:46:12Z")

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Some update of the sciml packages broke our project, see: Now I want to change \`Project.toml to make it work again, but this is very time-consuming, because after the first package that fails to pre-compile, it continu…

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## [Unable to add an issue in LinearSolve.jl](https://discourse.julialang.org/t/unable-to-add-an-issue-in-linearsolve-jl/136508)

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**Author:** [@John\_Washbourne](https://discourse.julialang.org/u/John_Washbourne)\
**Replies:** 2\
**Last updated:** [April 1, 2026, 5:14pm UTC](https://discourse.julialang.org/t/unable-to-add-an-issue-in-linearsolve-jl/136508 "2026-04-01T17:14:23Z")

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I am unable to add an issue or question at GitHub - SciML/LinearSolve.jl: LinearSolve.jl: High-Performance Unified Interface for Linear Solvers in Julia. Easily switch between factorization and Krylov methods, add precon…

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## [Improving the speed for the forward solve of a Universal Differential Equation (UDE)](https://discourse.julialang.org/t/improving-the-speed-for-the-forward-solve-of-a-universal-differential-equation-ude/130583)

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**Author:** [@Ashima\_Kalathingal](https://discourse.julialang.org/u/Ashima_Kalathingal)\
**Replies:** 21\
**Last updated:** [March 30, 2026, 5:24pm UTC](https://discourse.julialang.org/t/improving-the-speed-for-the-forward-solve-of-a-universal-differential-equation-ude/130583 "2026-03-30T17:24:00Z")

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Hello everyone, I have a UDE here, and I am trying to improve its speed during the forward solve so that the optimization is also faster. Right now optimization part is very slow. Here is a working code you can try out …

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## [The role of parameter p in the SciML ecosystem](https://discourse.julialang.org/t/the-role-of-parameter-p-in-the-sciml-ecosystem/136363)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 5\
**Last updated:** [March 24, 2026, 9:54pm UTC](https://discourse.julialang.org/t/the-role-of-parameter-p-in-the-sciml-ecosystem/136363 "2026-03-24T21:54:13Z")

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Many (most?) of the SciML libraries feature a parameter p in their high-level API. I would like to learn more about the motivation for this design, and the actual specs for what it can be and what it is intended for. Eg…

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## [Building a UI for a SciML biological model: Genie.jl (Web App) vs. Makie.jl (Local GUI)?](https://discourse.julialang.org/t/building-a-ui-for-a-sciml-biological-model-genie-jl-web-app-vs-makie-jl-local-gui/136344)

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**Author:** [@Luca\_Maria\_Moccia](https://discourse.julialang.org/u/Luca_Maria_Moccia)\
**Replies:** 17\
**Last updated:** [March 24, 2026, 1:38pm UTC](https://discourse.julialang.org/t/building-a-ui-for-a-sciml-biological-model-genie-jl-web-app-vs-makie-jl-local-gui/136344 "2026-03-24T13:38:56Z")

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Hi everyone, My colleague and I are currently doing our Master’s internship, and we are working on a synaptic plasticity model built with the SciML ecosystem. Our main goal right now is to build a user-friendly interfa…

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## [@mtkcompile / System(...): unknowns and required u0 change when I rename a component](https://discourse.julialang.org/t/mtkcompile-system-unknowns-and-required-u0-change-when-i-rename-a-component/136071)

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**Author:** [@celia.bat](https://discourse.julialang.org/u/celia.bat)\
**Replies:** 4\
**Last updated:** [March 18, 2026, 4:33pm UTC](https://discourse.julialang.org/t/mtkcompile-system-unknowns-and-required-u0-change-when-i-rename-a-component/136071 "2026-03-18T16:33:55Z")

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Hi everyone, I am working with a fairly large ModelingToolkit model built from components. I compile it with something like: @mtkcompile sys = System(assembly, t; systems = elements) where elements is the list of the …

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## [Interest for GSoC 2026: Global Error Estimation and Control for Differential Equations](https://discourse.julialang.org/t/interest-for-gsoc-2026-global-error-estimation-and-control-for-differential-equations/136246)

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**Author:** [@Emanuele-Elias](https://discourse.julialang.org/u/Emanuele-Elias)\
**Replies:** 0\
**Last updated:** [March 17, 2026, 10:30pm UTC](https://discourse.julialang.org/t/interest-for-gsoc-2026-global-error-estimation-and-control-for-differential-equations/136246 "2026-03-17T22:30:14Z")

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Hi everyone, My name is Emanuele, I am an applied math and data science master’s student, and I am interested in the GSoC 2026 project: “Global Error Estimation and Control for Differential Equations.” I have put toget…

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## [Julia's SciML and UDE in temporal networks: preprint out](https://discourse.julialang.org/t/julias-sciml-and-ude-in-temporal-networks-preprint-out/136099)

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**Author:** [@gvdr](https://discourse.julialang.org/u/gvdr)\
**Replies:** 1\
**Last updated:** [March 9, 2026, 10:37am UTC](https://discourse.julialang.org/t/julias-sciml-and-ude-in-temporal-networks-preprint-out/136099 "2026-03-09T10:37:07Z")

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Hi everyone, I got a new pre-print out on arXiv, that uses the Julia’s SciML ecosystem quite a bit. The base idea is: if we consider a complex network that changes in time as a dynamical system (and take a nice model …

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## [Precompilation error with Catalyst (Circular dependency)](https://discourse.julialang.org/t/precompilation-error-with-catalyst-circular-dependency/136013)

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**Author:** [@Luca\_Maria\_Moccia](https://discourse.julialang.org/u/Luca_Maria_Moccia)\
**Replies:** 3\
**Last updated:** [March 4, 2026, 4:23pm UTC](https://discourse.julialang.org/t/precompilation-error-with-catalyst-circular-dependency/136013 "2026-03-04T16:23:37Z")

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Hello everyone, I am currently working on a biology modeling project for my Master’s internship, using an environment provided by my lab. When trying to load our local package (which depends heavily on the SciML ecosys…

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## [Should NonlinearLeastSquaresProblem be used for deep learning?](https://discourse.julialang.org/t/should-nonlinearleastsquaresproblem-be-used-for-deep-learning/135793)

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**Author:** [@dmetivie](https://discourse.julialang.org/u/dmetivie)\
**Replies:** 11\
**Last updated:** [February 24, 2026, 4:03pm UTC](https://discourse.julialang.org/t/should-nonlinearleastsquaresproblem-be-used-for-deep-learning/135793 "2026-02-24T16:03:28Z")

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From this JuliaCon talk Fast and Robust Least Squares / Curve Fitting by @ChrisRackauckas, I gathered that if you have a L2 loss function then you should be using NonlinearLeastSquaresProblem from the NonlinearSolve.jl p…

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## [Different initial conditions / trajectories when updating parameters with setp+remake vs re-solving steady state (ModelingToolkit ODEProblem)](https://discourse.julialang.org/t/different-initial-conditions-trajectories-when-updating-parameters-with-setp-remake-vs-re-solving-steady-state-modelingtoolkit-odeproblem/135676)

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**Author:** [@celia.bat](https://discourse.julialang.org/u/celia.bat)\
**Replies:** 2\
**Last updated:** [February 16, 2026, 4:20pm UTC](https://discourse.julialang.org/t/different-initial-conditions-trajectories-when-updating-parameters-with-setp-remake-vs-re-solving-steady-state-modelingtoolkit-odeproblem/135676 "2026-02-16T16:20:50Z")

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Hi all, I’m confused about how remake interacts with initialization / consistent initial conditions in a ModelingToolkit workflow where I: Solve a “static” system using a SteadyStateProblem to get an equilibrium. Use …

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## [Stokes solver as an ODEproblem takes time to initiate](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317)

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**Author:** [@Iddingsite](https://discourse.julialang.org/u/Iddingsite)\
**Replies:** 6\
**Last updated:** [January 29, 2026, 10:15am UTC](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317 "2026-01-29T10:15:42Z")

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Hi everyone. I wrote a small code to solve 2D linear visco-elastic Stokes using finite difference and OrdinaryDiffEq to test how that would work out. So, in this case, I only have algebraic equations and have some param…

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## [Adopt the SciML Style Guide for Julia Base and Standard Library?](https://discourse.julialang.org/t/adopt-the-sciml-style-guide-for-julia-base-and-standard-library/134845)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 10\
**Last updated:** [January 3, 2026, 11:51pm UTC](https://discourse.julialang.org/t/adopt-the-sciml-style-guide-for-julia-base-and-standard-library/134845 "2026-01-03T23:51:09Z")

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After thinking about docstrings from another post, I was wondering if the Julia Style Guide, particularly for Core, Base, and the standard libraries should be further specified, particularly for docstrings. Perhaps a …

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## [RFC: Reverse Communication (ask/tell) adapter for function-style optimizers in Julia?](https://discourse.julialang.org/t/rfc-reverse-communication-ask-tell-adapter-for-function-style-optimizers-in-julia/134803)

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**Author:** [@karei](https://discourse.julialang.org/u/karei)\
**Replies:** 1\
**Last updated:** [December 30, 2025, 7:44pm UTC](https://discourse.julialang.org/t/rfc-reverse-communication-ask-tell-adapter-for-function-style-optimizers-in-julia/134803 "2025-12-30T19:44:02Z")

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Hi all, I’d like to start a discussion on a generic Reverse Communication Interface (RCI), i.e. an ask/tell-style session API, for Julia’s optimization ecosystem. The idea is to sit on top of existing “function-style” o…

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## [Free final time problem formulation using ModelingToolkit and InfiniteOpt](https://discourse.julialang.org/t/free-final-time-problem-formulation-using-modelingtoolkit-and-infiniteopt/134735)

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**Author:** [@PhysicsBender](https://discourse.julialang.org/u/PhysicsBender)\
**Replies:** 2\
**Last updated:** [December 26, 2025, 8:54am UTC](https://discourse.julialang.org/t/free-final-time-problem-formulation-using-modelingtoolkit-and-infiniteopt/134735 "2025-12-26T08:54:06Z")

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Hello all, I am a new Julia user coming from a Modelica background and I am trying to experiment with Modeling Toolkit and dynamic optimisation. I was trying to follow this example (\[Solving Dynamic Optimization Proble…

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## [Stochastic filtration problem](https://discourse.julialang.org/t/stochastic-filtration-problem/134713)

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**Author:** [@ymuv1](https://discourse.julialang.org/u/ymuv1)\
**Replies:** 1\
**Last updated:** [December 23, 2025, 7:13pm UTC](https://discourse.julialang.org/t/stochastic-filtration-problem/134713 "2025-12-23T19:13:46Z")

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Hi all, I’m working with a physical system whose state u(t) follows an SDE du=f(u,t)dt+g(u,t)dW\_t The system produces a measured signal Y\_t given by dY\_t = h(u,t)dt+dW\_t where dW\_t is the same Wiener increment in bo…

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## [Correctness Issue in NeuralOperators.jl: Mode truncation in SpectralConv excludes negative low-frequency modes](https://discourse.julialang.org/t/correctness-issue-in-neuraloperators-jl-mode-truncation-in-spectralconv-excludes-negative-low-frequency-modes/134403)

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**Author:** [@Azamat](https://discourse.julialang.org/u/Azamat)\
**Replies:** 2\
**Last updated:** [December 9, 2025, 8:26am UTC](https://discourse.julialang.org/t/correctness-issue-in-neuraloperators-jl-mode-truncation-in-spectralconv-excludes-negative-low-frequency-modes/134403 "2025-12-09T08:26:17Z")

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I was looking at the mode truncation logic in NeuralOperators.jl and have a question about correctness. Link: NeuralOperators.jl/src/transform.jl at 39f8a3c6dc974e711c8de8a8fde804e096098157 · SciML/NeuralOperators.jl · …

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## [Using Neural ODEs to learn a family of ODEs (with Automatic Differentiation)](https://discourse.julialang.org/t/using-neural-odes-to-learn-a-family-of-odes-with-automatic-differentiation/134348)

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**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 13\
**Last updated:** [December 9, 2025, 1:59am UTC](https://discourse.julialang.org/t/using-neural-odes-to-learn-a-family-of-odes-with-automatic-differentiation/134348 "2025-12-09T01:59:34Z")

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I am running into issues when trying to use reverse-mode automatic differentiation via Zygote when trying to solve families of Given u(t), we can train a neural ODE to find the underlying ODE du/dt = f(u, t). For examp…

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## [Minimum Working Example (MWE) of a SINDy problem showing error](https://discourse.julialang.org/t/minimum-working-example-mwe-of-a-sindy-problem-showing-error/134013)

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**Author:** [@Ashima\_Kalathingal](https://discourse.julialang.org/u/Ashima_Kalathingal)\
**Replies:** 2\
**Last updated:** [December 5, 2025, 11:45pm UTC](https://discourse.julialang.org/t/minimum-working-example-mwe-of-a-sindy-problem-showing-error/134013 "2025-12-05T23:45:26Z")

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Hello all, The following is a MWE for a problem I am working on. Here I am trying to fit Qgen as a function of I,u\[1\],u\[2\] using a SINDy algorithm but I am running into errors. Here is the code using OrdinaryDiffEq us…

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## [ForwardDiff with ModelingToolkit: Type conversion error in MTKParameters with DAE systems](https://discourse.julialang.org/t/forwarddiff-with-modelingtoolkit-type-conversion-error-in-mtkparameters-with-dae-systems/134145)

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**Author:** [@Danijel-Zadravec](https://discourse.julialang.org/u/Danijel-Zadravec)\
**Replies:** 2\
**Last updated:** [December 1, 2025, 12:21pm UTC](https://discourse.julialang.org/t/forwarddiff-with-modelingtoolkit-type-conversion-error-in-mtkparameters-with-dae-systems/134145 "2025-12-01T12:21:26Z")

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Hi everyone, I’m encountering a MethodError when trying to follow this example from the ModelingToolkit documentation. The problem seems to be related with dual number propagation in ODEProblems that have the property: …

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## [Adaptive barrier method for constrained optimization](https://discourse.julialang.org/t/adaptive-barrier-method-for-constrained-optimization/134150)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 6\
**Last updated:** [December 1, 2025, 8:57am UTC](https://discourse.julialang.org/t/adaptive-barrier-method-for-constrained-optimization/134150 "2025-12-01T08:57:32Z")

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Hi all, I’m refactoring some old R code into Julia. In R I was using constrOptim: Linearly Constrained Optimization which lets us use constraints like U \\theta - c \\geq 0, where \\theta is our parameters to be optimized, U…

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