# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=3

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

**Page:** 4

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## [Spiking Neural Networks](https://discourse.julialang.org/t/spiking-neural-networks/63270)

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**Author:** [@mefob](https://discourse.julialang.org/u/mefob)\
**Replies:** 33\
**Last updated:** [July 9, 2026, 4:32pm UTC](https://discourse.julialang.org/t/spiking-neural-networks/63270 "2026-07-09T16:32:19Z")

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What is the state of the art for modeling spiking neural networks in Julia? I haven’t found much recent work: Spiking Neural Network (Discussion from 2019 on implementing a SNN as an ODE) GitHub - AStupidBear/Spikin…

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## [Interpolating solution to constrained BVP](https://discourse.julialang.org/t/interpolating-solution-to-constrained-bvp/137989)

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**Author:** [@kar15](https://discourse.julialang.org/u/kar15)\
**Replies:** 3\
**Last updated:** [July 9, 2026, 7:41am UTC](https://discourse.julialang.org/t/interpolating-solution-to-constrained-bvp/137989 "2026-07-09T07:41:02Z")

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Hi all! When trying to find interpolated values of a solution to a constrained BVP using SciMLs collocation method, I get an error. Here is a MWE: using BoundaryValueDiffEq, OptimizationIpopt function f!(du, u, p, t) …

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## [Mutable Computational Graphs in Pure Julia: Performing "Hot Surgery" on a LLaMA Transformer](https://discourse.julialang.org/t/mutable-computational-graphs-in-pure-julia-performing-hot-surgery-on-a-llama-transformer/138018)

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**Author:** [@Khemais\_Abdallah](https://discourse.julialang.org/u/Khemais_Abdallah)\
**Replies:** 0\
**Last updated:** [July 8, 2026, 11:53pm UTC](https://discourse.julialang.org/t/mutable-computational-graphs-in-pure-julia-performing-hot-surgery-on-a-llama-transformer/138018 "2026-07-08T23:53:25Z")

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Hi everyone, I am Abdallah Khemais. As an Instructor of Applied Mathematics and AI at ISITCOM Sousse Tunisia, with over two decades of experience, my work focuses on the intersection of formal mathematical theory and hig…

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## [ModelingToolkit.jl / Multibody.jl with interpolated joint properties](https://discourse.julialang.org/t/modelingtoolkit-jl-multibody-jl-with-interpolated-joint-properties/133754)

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**Author:** [@Jskacines](https://discourse.julialang.org/u/Jskacines)\
**Replies:** 11\
**Last updated:** [July 8, 2026, 2:52pm UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-multibody-jl-with-interpolated-joint-properties/133754 "2026-07-08T14:52:43Z")

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Hello Julia community, I am working on a multibody dynamics simulation, and was looking to use ModelingToolkit.jl along with Multibody.jl The specific problem I am working on involves an externally solved mapping of jo…

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## [Initialization in ModelingToolkit](https://discourse.julialang.org/t/initialization-in-modelingtoolkit/137983)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [July 7, 2026, 12:17pm UTC](https://discourse.julialang.org/t/initialization-in-modelingtoolkit/137983 "2026-07-07T12:17:13Z")

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Questions, etc. If any of the functionality discussed below already exists, please let me know! Does anyone else find the ideas useful? Or am I the only one that struggles with initialization? If anyone with better prog…

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## [Optimization.jl - Define the objective function and its gradient in the same function](https://discourse.julialang.org/t/optimization-jl-define-the-objective-function-and-its-gradient-in-the-same-function/137968)

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**Author:** [@Maucejo](https://discourse.julialang.org/u/Maucejo)\
**Replies:** 3\
**Last updated:** [July 7, 2026, 6:30am UTC](https://discourse.julialang.org/t/optimization-jl-define-the-objective-function-and-its-gradient-in-the-same-function/137968 "2026-07-07T06:30:44Z")

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Hi all, I am working on an optimization problem involving Complex Gaussian Processes and Kalman Filter. To optimize the hyperparameters of the kernels, I use Optimization.jl. Because I have calculated the analytical grad…

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## [Mooncake.jl with variable sized input](https://discourse.julialang.org/t/mooncake-jl-with-variable-sized-input/137943)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 5\
**Last updated:** [July 6, 2026, 1:58pm UTC](https://discourse.julialang.org/t/mooncake-jl-with-variable-sized-input/137943 "2026-07-06T13:58:40Z")

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This post is intended as a log for people interested in Mooncake. Similarly, I am interested in feedback. Background: I am interested in learning from structured data, under which you can think about JSON documents. I a…

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## [Blog post on GPU ecosystem](https://discourse.julialang.org/t/blog-post-on-gpu-ecosystem/137971)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 0\
**Last updated:** [July 6, 2026, 1:28pm UTC](https://discourse.julialang.org/t/blog-post-on-gpu-ecosystem/137971 "2026-07-06T13:28:50Z")

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Hi all! Following discussions on Slack, I got a blog post started to list the major packages in Julia’s GPU ecosystem and show how they interact. It’s getting close to completion and I would appreciate reviews / suggest…

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## [Decomposing a scenario-feasibility MILP with binary recourse in JuMP](https://discourse.julialang.org/t/decomposing-a-scenario-feasibility-milp-with-binary-recourse-in-jump/137898)

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**Author:** [@decomp-lab](https://discourse.julialang.org/u/decomp-lab)\
**Replies:** 10\
**Last updated:** [July 5, 2026, 10:52pm UTC](https://discourse.julialang.org/t/decomposing-a-scenario-feasibility-milp-with-binary-recourse-in-jump/137898 "2026-07-05T22:52:47Z")

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I have a two-stage multi-scenario MILP in JuMP with an inventory/order-flow structure. The first-stage variables are shared across all scenarios. Each scenario then has its own continuous flow variables and binary timin…

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## [Small step size in LBFGS for neural network with complex values](https://discourse.julialang.org/t/small-step-size-in-lbfgs-for-neural-network-with-complex-values/137946)

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**Author:** [@Knud\_Sorensen](https://discourse.julialang.org/u/Knud_Sorensen)\
**Replies:** 3\
**Last updated:** [July 5, 2026, 6:46pm UTC](https://discourse.julialang.org/t/small-step-size-in-lbfgs-for-neural-network-with-complex-values/137946 "2026-07-05T18:46:42Z")

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I wrote my own LBFGS code for a neural network with complex values. It worked until the step size became to small to change the network because of floating point position. Has anyone had similar problems and know how t…

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## [How to use Multibody.jl?](https://discourse.julialang.org/t/how-to-use-multibody-jl/134354)

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**Author:** [@SietseAchterop](https://discourse.julialang.org/u/SietseAchterop)\
**Replies:** 8\
**Last updated:** [July 3, 2026, 12:16pm UTC](https://discourse.julialang.org/t/how-to-use-multibody-jl/134354 "2026-07-03T12:16:15Z")

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Hello all, I am new to Julia, now on version 1.12.2 on Linux/Debian version 13.2. Played around with it and with Dyad. Now trying to use the Pendulum example from Multibody.jl I can do add and then using ModelingTool…

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## [Axis padding](https://discourse.julialang.org/t/axis-padding/137904)

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**Author:** [@grero](https://discourse.julialang.org/u/grero)\
**Replies:** 2\
**Last updated:** [July 3, 2026, 12:37am UTC](https://discourse.julialang.org/t/axis-padding/137904 "2026-07-03T00:37:36Z")

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Is there a way to pad an axis in Makie without modifying the data limits? I’m trying to use brackets to highlight a range in a heat map, like in the following little example. using Makie function bracket\_test() fig…

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## [Invertible Neural Networks](https://discourse.julialang.org/t/invertible-neural-networks/137909)

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**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 0\
**Last updated:** [July 2, 2026, 2:40pm UTC](https://discourse.julialang.org/t/invertible-neural-networks/137909 "2026-07-02T14:40:20Z")

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I was looking at doing some modelling work using invertible neural-networks in Julia with Lux.jl. There aren’t many options, but I found GitHub - slimgroup/InvertibleNetworks.jl: A Julia framework for invertible neural …

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## [Why doesn't the solver reach the optimal solution?](https://discourse.julialang.org/t/why-doesnt-the-solver-reach-the-optimal-solution/137852)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 7\
**Last updated:** [July 1, 2026, 3:14am UTC](https://discourse.julialang.org/t/why-doesnt-the-solver-reach-the-optimal-solution/137852 "2026-07-01T03:14:12Z")

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Hello, I am working on improving a formulation of an optimization problem with JuMP and have encountered an issue that has been blocking me for several days. After extensive debugging and manual verification, I am reason…

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## [Solving the Helium Eigenvalue Problem—where to start?](https://discourse.julialang.org/t/solving-the-helium-eigenvalue-problem-where-to-start/137783)

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**Author:** [@ducksoverip](https://discourse.julialang.org/u/ducksoverip)\
**Replies:** 8\
**Last updated:** [June 29, 2026, 7:18pm UTC](https://discourse.julialang.org/t/solving-the-helium-eigenvalue-problem-where-to-start/137783 "2026-06-29T19:18:53Z")

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I have inherited Fortran code (the same one in this paper) that solves the time-independent Schrodinger equation for the ground state of the helium atom. This is generally a very difficult problem because the Schrodinger…

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## [Boundary Condition Error in MethodOfLines](https://discourse.julialang.org/t/boundary-condition-error-in-methodoflines/137819)

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**Author:** [@ducksoverip](https://discourse.julialang.org/u/ducksoverip)\
**Replies:** 2\
**Last updated:** [June 29, 2026, 12:53pm UTC](https://discourse.julialang.org/t/boundary-condition-error-in-methodoflines/137819 "2026-06-29T12:53:59Z")

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I’m trying to use MethodOfLines to solve the time-independent Schrodinger equation for hydrogen, as a prelude to more complicated systems. The equation is as follows: \\nabla^2 \\psi(\\vec{r}) - \\frac{1}{r}\\psi(\\vec{r}) =…

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## [AD using Enzyme in ODE problem with DataInterpolations](https://discourse.julialang.org/t/ad-using-enzyme-in-ode-problem-with-datainterpolations/137771)

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**Author:** [@imre](https://discourse.julialang.org/u/imre)\
**Replies:** 3\
**Last updated:** [June 29, 2026, 7:47am UTC](https://discourse.julialang.org/t/ad-using-enzyme-in-ode-problem-with-datainterpolations/137771 "2026-06-29T07:47:07Z")

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Hello, I have an ODE problem which uses DataInterpolations.jl to obtain input values for the system at specific timepoints in order to compute dx. I want to use Enzyme.jl to compute the gradients with respect to paramete…

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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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## [How does ForwardDiff.jl and FiniteDiff.jl handle edge-hitting cases?](https://discourse.julialang.org/t/how-does-forwarddiff-jl-and-finitediff-jl-handle-edge-hitting-cases/137828)

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**Author:** [@Xu\_Shan](https://discourse.julialang.org/u/Xu_Shan)\
**Replies:** 3\
**Last updated:** [June 27, 2026, 11:18pm UTC](https://discourse.julialang.org/t/how-does-forwarddiff-jl-and-finitediff-jl-handle-edge-hitting-cases/137828 "2026-06-27T23:18:02Z")

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Hi guys, I am using ForwardDiff.jl to calculate the parameter uncertainty in my model (see below about the more detailed information…). I am wondering, how does ForwardDiff.jl and FiniteDiff.jl handle the edge-hitting p…

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## [How to make a heatmap with pgfplotsx?](https://discourse.julialang.org/t/how-to-make-a-heatmap-with-pgfplotsx/75128)

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**Author:** [@ccmejia](https://discourse.julialang.org/u/ccmejia)\
**Replies:** 4\
**Last updated:** [June 27, 2026, 2:08pm UTC](https://discourse.julialang.org/t/how-to-make-a-heatmap-with-pgfplotsx/75128 "2026-06-27T14:08:07Z")

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Hi there! Which is the straightforward pgfplotsx way to make heatmap figure? For Plots is so easy: V = rand(20, 20) heatmap(V) Thanks in advanced!

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## [Hexaly solver with JuMP](https://discourse.julialang.org/t/hexaly-solver-with-jump/124827)

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**Author:** [@baprata](https://discourse.julialang.org/u/baprata)\
**Replies:** 8\
**Last updated:** [June 26, 2026, 7:45pm UTC](https://discourse.julialang.org/t/hexaly-solver-with-jump/124827 "2026-06-26T19:45:57Z")

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Dear Colleagues, Is it feasible to call the Hexaly solver (https://www.hexaly.com/) within the JuMP library? If so, could someone provide some source code with an example? Best regards, Bruno

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## [Question about SDDP.jl](https://discourse.julialang.org/t/question-about-sddp-jl/137741)

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**Author:** [@david-hri](https://discourse.julialang.org/u/david-hri)\
**Replies:** 2\
**Last updated:** [June 26, 2026, 8:15am UTC](https://discourse.julialang.org/t/question-about-sddp-jl/137741 "2026-06-26T08:15:57Z")

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Hello, I am new to SDDP.jl, so my question may be naive. I currently have a working SDDP model in which the generation profits are computed using a fixed hydraulic head effect (so the efficiency does not depend on the…

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## [How to link PolarAxis in Makie.jl](https://discourse.julialang.org/t/how-to-link-polaraxis-in-makie-jl/137787)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 3\
**Last updated:** [June 25, 2026, 11:30am UTC](https://discourse.julialang.org/t/how-to-link-polaraxis-in-makie-jl/137787 "2026-06-25T11:30:21Z")

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I know we can use Makie.linkaxes(fig.content...) when the content is a collection of Makie.Axis. If I try the same command with Makie.PolarAxis, I get an error. Is it currently not supported?

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## [Sensitivity Analysis on ODE system](https://discourse.julialang.org/t/sensitivity-analysis-on-ode-system/137757)

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**Author:** [@violabini](https://discourse.julialang.org/u/violabini)\
**Replies:** 4\
**Last updated:** [June 25, 2026, 9:40am UTC](https://discourse.julialang.org/t/sensitivity-analysis-on-ode-system/137757 "2026-06-25T09:40:40Z")

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Hi everyone, I am trying to use automatic differentiation in julia to compute the Jacobian of my outputs wrt my design variables for local sensitivity, but my ODEs are nearly coupled as for example du\[3\]=A\*du\[2\]+B u\[1\].…

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## [How to Create Global Parameters in ModelingToolkit.jl](https://discourse.julialang.org/t/how-to-create-global-parameters-in-modelingtoolkit-jl/60065)

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**Author:** [@Brad\_Carman](https://discourse.julialang.org/u/Brad_Carman)\
**Replies:** 6\
**Last updated:** [June 25, 2026, 9:37am UTC](https://discourse.julialang.org/t/how-to-create-global-parameters-in-modelingtoolkit-jl/60065 "2026-06-25T09:37:00Z")

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Is it possible to create global parameters? For example, when modeling a gas or fluid, it would be convenient to define them globally, similar to how is done in SimScape with a domain definition. I attempted to create …

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## [Solver differences between sim!(::SimModel) and sim!(::PredictiveController) in ModelPredictiveControl.jl](https://discourse.julialang.org/t/solver-differences-between-sim-simmodel-and-sim-predictivecontroller-in-modelpredictivecontrol-jl/120819)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 19\
**Last updated:** [June 24, 2026, 5:15pm UTC](https://discourse.julialang.org/t/solver-differences-between-sim-simmodel-and-sim-predictivecontroller-in-modelpredictivecontrol-jl/120819 "2026-06-24T17:15:12Z")

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I am trying to use NMPC in ModelPredictiveControl.jl, but while my model runs with sim!(model) it gets a boundserror with sim!(nmpc). To try to find out what is going on, I tried to run the two sim! functions on a simpl…

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## [Memory blow-up when solving a sparse affine Hermitian SDP translated from YALMIP to JuMP](https://discourse.julialang.org/t/memory-blow-up-when-solving-a-sparse-affine-hermitian-sdp-translated-from-yalmip-to-jump/137744)

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**Author:** [@hz-xiaxz](https://discourse.julialang.org/u/hz-xiaxz)\
**Replies:** 10\
**Last updated:** [June 23, 2026, 7:24am UTC](https://discourse.julialang.org/t/memory-blow-up-when-solving-a-sparse-affine-hermitian-sdp-translated-from-yalmip-to-jump/137744 "2026-06-23T07:24:42Z")

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Hi JuMP developers, I am translating a MATLAB/YALMIP semidefinite program to Julia/JuMP + MosekTools. The model comes from a many-body bootstrap calculation. The MATLAB/YALMIP version can solve a small 3 x 3 lattice cas…

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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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## [How can I keep a GLMakie window open?](https://discourse.julialang.org/t/how-can-i-keep-a-glmakie-window-open/137713)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [June 20, 2026, 3:54pm UTC](https://discourse.julialang.org/t/how-can-i-keep-a-glmakie-window-open/137713 "2026-06-20T15:54:42Z")

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I switched from PythonPlot to GLMakie, and in PythonPlot, I could do: plt.show(block=true) at the end of a script that is run from the command line (not from the REPL) to keep the plot window open until the user closes…

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## [Nested submodels slow down Turing ~7x (Mooncake AD)](https://discourse.julialang.org/t/nested-submodels-slow-down-turing-7x-mooncake-ad/137679)

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**Author:** [@simonsteiger](https://discourse.julialang.org/u/simonsteiger)\
**Replies:** 5\
**Last updated:** [June 20, 2026, 2:30pm UTC](https://discourse.julialang.org/t/nested-submodels-slow-down-turing-7x-mooncake-ad/137679 "2026-06-20T14:30:36Z")

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I just discovered that nesting several submodels in Turing.jl seems to considerably slow down sampling (I only tried Mooncake.jl so far). The code below shows this with the eight schools dataset. I’ve deliberately made …

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