# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=70

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**Page:** 71

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## [Optimization using GLPK](https://discourse.julialang.org/t/optimization-using-glpk/107210)

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**Author:** [@doriiido](https://discourse.julialang.org/u/doriiido)\
**Replies:** 15\
**Last updated:** [November 28, 2024, 11:14pm UTC](https://discourse.julialang.org/t/optimization-using-glpk/107210 "2024-11-28T23:14:31Z")

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I am trying to find an optimal number of employees to satisfy a scheduling problem, this is my code: using JuMP using GLPK # Constants and parameters Wjk = \[19 16 22 22 22 22 22; 19 16 22 22 22 22 22; 14 11 16 16 16 16…

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## [SCIP constraints](https://discourse.julialang.org/t/scip-constraints/123206)

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**Author:** [@Rajender\_Mudigonda](https://discourse.julialang.org/u/Rajender_Mudigonda)\
**Replies:** 2\
**Last updated:** [November 28, 2024, 7:24pm UTC](https://discourse.julialang.org/t/scip-constraints/123206 "2024-11-28T19:24:31Z")

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When using SCIP solver, what is the alternative for compute\_conflict!(model) to identify constraint conflicts?

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## [BifurcationKit: detecting fold bifurcation](https://discourse.julialang.org/t/bifurcationkit-detecting-fold-bifurcation/123096)

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**Author:** [@mmplac14](https://discourse.julialang.org/u/mmplac14)\
**Replies:** 20\
**Last updated:** [November 28, 2024, 5:28pm UTC](https://discourse.julialang.org/t/bifurcationkit-detecting-fold-bifurcation/123096 "2024-11-28T17:28:01Z")

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This post is related to my previous one. I am new to bifurcation analyis and I am working with BifurcationKit to reproduce the bifurcation analysis performed by Grimbert Faugueras on the Jansen-Rit model. Specifically,…

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## [Choosing a package for univariate (convex) optimization in Julia](https://discourse.julialang.org/t/choosing-a-package-for-univariate-convex-optimization-in-julia/109089)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 8\
**Last updated:** [November 28, 2024, 4:34pm UTC](https://discourse.julialang.org/t/choosing-a-package-for-univariate-convex-optimization-in-julia/109089 "2024-11-28T16:34:55Z")

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I need to solve 1d convex optimization programs, where I have access to all derivatives. Ideally I’d use Optim.jl but the interface only supports vectors. The backend NLSolvers.jl works but the documentation is not as de…

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## [How to improve the performance of CUDA kernel function which loop on a large struct array](https://discourse.julialang.org/t/how-to-improve-the-performance-of-cuda-kernel-function-which-loop-on-a-large-struct-array/123139)

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**Author:** [@liutao](https://discourse.julialang.org/u/liutao)\
**Replies:** 4\
**Last updated:** [November 28, 2024, 3:47pm UTC](https://discourse.julialang.org/t/how-to-improve-the-performance-of-cuda-kernel-function-which-loop-on-a-large-struct-array/123139 "2024-11-28T15:47:08Z")

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Dear all, I have a problem about the performance of CUDA kernel function which loop on a large struct array. Loop on the struct array is neccesaary for me. The MWE is as follows: using CUDA using Adapt using BenchmarkT…

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## [How to access field values in ParallelStencil.jl custom struct](https://discourse.julialang.org/t/how-to-access-field-values-in-parallelstencil-jl-custom-struct/123172)

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**Author:** [@pchaubal](https://discourse.julialang.org/u/pchaubal)\
**Replies:** 2\
**Last updated:** [November 28, 2024, 2:04pm UTC](https://discourse.julialang.org/t/how-to-access-field-values-in-parallelstencil-jl-custom-struct/123172 "2024-11-28T14:04:25Z")

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I am trying to use a custom struct with ParallelStencil.jl. I define the custom struct as @CellType Field2D fieldnames=(xx, yy, zz) Then I initialize it for 2 variables as F1 = @zeros( nx, ny, celltype=Field2D) F2 = …

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## [Difference between solutions obtained from ODE model and ModelingToolkit model](https://discourse.julialang.org/t/difference-between-solutions-obtained-from-ode-model-and-modelingtoolkit-model/123157)

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**Author:** [@Maucejo](https://discourse.julialang.org/u/Maucejo)\
**Replies:** 3\
**Last updated:** [November 28, 2024, 9:41am UTC](https://discourse.julialang.org/t/difference-between-solutions-obtained-from-ode-model-and-modelingtoolkit-model/123157 "2024-11-28T09:41:21Z")

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Hi all, I am starting using OrdinaryDiffEq and ModelingToolkit and try to learn how to use these packages properly. To this end, I took the double pendulum as an example. For the OrdinaryDiffEq model, I have implemented…

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## [OptimizationSystem from a set of multiple equations](https://discourse.julialang.org/t/optimizationsystem-from-a-set-of-multiple-equations/122809)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 16\
**Last updated:** [November 28, 2024, 8:53am UTC](https://discourse.julialang.org/t/optimizationsystem-from-a-set-of-multiple-equations/122809 "2024-11-28T08:53:30Z")

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I have a set of equations where there are some input variables and one output variable. I want to minimize the output variable, and thought to do this with an OptimizationProblem. In this example, distance is the only in…

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## [Parameter Estimation with partial data](https://discourse.julialang.org/t/parameter-estimation-with-partial-data/123192)

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**Author:** [@Fourier](https://discourse.julialang.org/u/Fourier)\
**Replies:** 2\
**Last updated:** [November 28, 2024, 8:35am UTC](https://discourse.julialang.org/t/parameter-estimation-with-partial-data/123192 "2024-11-28T08:35:35Z")

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Hi, I have a differential equation, for example the differential equation for a pendulum, like in this example from DiffEqBayes. I would like to estimate the parameters. However I only know a part of the solution, for …

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## [Sin(x), cos(x) w/ Gurobi?](https://discourse.julialang.org/t/sin-x-cos-x-w-gurobi/123179)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 2\
**Last updated:** [November 28, 2024, 2:19am UTC](https://discourse.julialang.org/t/sin-x-cos-x-w-gurobi/123179 "2024-11-28T02:19:08Z")

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Can I use sinusoidal functions with JuMP/Gurobi? something like: using JuMP, Gurobi m=Model(Gurobi.Optimizer) @variable(m, -2π \<= x \<= 2π) @objective(m, Min, cos(x)) optimize!(m) It seems like there’s a section on sine…

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## [DataFrames: Which formats (if any) support saving of metadata](https://discourse.julialang.org/t/dataframes-which-formats-if-any-support-saving-of-metadata/123134)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 6\
**Last updated:** [November 27, 2024, 5:23pm UTC](https://discourse.julialang.org/t/dataframes-which-formats-if-any-support-saving-of-metadata/123134 "2024-11-27T17:23:37Z")

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Are there file formats that support saving of metadata (global and columnar)?

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## [Periodic solution to a forced oscillator ODE](https://discourse.julialang.org/t/periodic-solution-to-a-forced-oscillator-ode/123080)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 10\
**Last updated:** [November 27, 2024, 5:32pm UTC](https://discourse.julialang.org/t/periodic-solution-to-a-forced-oscillator-ode/123080 "2024-11-27T17:32:22Z")

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I’m working with an ODE model. I’m looking for the periodic solution to a forced, non-conservative, non-linear and time-invariant oscillator. For example, something like x''(t) = - k (x(t) + 0.1 x^3(t)) - a x'(t) + A si…

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## [Create ForwardDiff.Dual is slow](https://discourse.julialang.org/t/create-forwarddiff-dual-is-slow/123093)

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**Author:** [@shady287](https://discourse.julialang.org/u/shady287)\
**Replies:** 5\
**Last updated:** [November 26, 2024, 6:13pm UTC](https://discourse.julialang.org/t/create-forwarddiff-dual-is-slow/123093 "2024-11-26T18:13:17Z")

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Hi all, I am using ForwardDiff to calculate a jacobian in a physical problem. Everything works and I am happy with the results. Now I would like to optimaze it but I am failing in doing so. As a start, I have a very la…

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## [Help Needed: S3 Connection Error with MinIO in Development Environment](https://discourse.julialang.org/t/help-needed-s3-connection-error-with-minio-in-development-environment/122957)

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**Author:** [@OgmaJ](https://discourse.julialang.org/u/OgmaJ)\
**Replies:** 9\
**Last updated:** [November 26, 2024, 9:16pm UTC](https://discourse.julialang.org/t/help-needed-s3-connection-error-with-minio-in-development-environment/122957 "2024-11-26T21:16:02Z")

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Hello community, I’m trying to connect to a MinIO instance (an S3-compatible provider) in my development environment using Julia and the AWS and AWSS3 packages. I’ve written a script to list buckets, but I’m encounterin…

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## [Global sensitivity analysis in a large parameter space - computational cost](https://discourse.julialang.org/t/global-sensitivity-analysis-in-a-large-parameter-space-computational-cost/93598)

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**Author:** [@Nick1](https://discourse.julialang.org/u/Nick1)\
**Replies:** 15\
**Last updated:** [November 26, 2024, 9:05pm UTC](https://discourse.julialang.org/t/global-sensitivity-analysis-in-a-large-parameter-space-computational-cost/93598 "2024-11-26T21:05:06Z")

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Hi everyone, I have been working in a large biochemical reaction network and I try to perform Global sensitivity analysis (GSA) (see my last post). I was wondering if there are any advice, or suggestions regarding the e…

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## [How to copy variables from one optimized JuMP model into another model?](https://discourse.julialang.org/t/how-to-copy-variables-from-one-optimized-jump-model-into-another-model/123103)

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**Author:** [@Realife\_Brahmin](https://discourse.julialang.org/u/Realife_Brahmin)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 6:44pm UTC](https://discourse.julialang.org/t/how-to-copy-variables-from-one-optimized-jump-model-into-another-model/123103 "2024-11-26T18:44:20Z")

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Hello everyone, I’m working on a multi-period optimization problem using Julia, JuMP, and Ipopt. My approach involves solving individual time-step optimization subproblems as separate JuMP models (sub\_model\_t0), then in…

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## [Enzyme Autodiff readonly error and working with batches of data](https://discourse.julialang.org/t/enzyme-autodiff-readonly-error-and-working-with-batches-of-data/123012)

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**Author:** [@turiya](https://discourse.julialang.org/u/turiya)\
**Replies:** 14\
**Last updated:** [November 26, 2024, 2:28pm UTC](https://discourse.julialang.org/t/enzyme-autodiff-readonly-error-and-working-with-batches-of-data/123012 "2024-11-26T14:28:35Z")

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I have the following MWE using Enzyme, Lux, Random n = 10 x\_batch = randn(2,n) y\_batch = randn(2,n) model = Chain(Parallel(vcat, Dense(2, 1, tanh), Dense(2,1,tanh)), Dense(2,1,tanh)) rng = Random.default\_rng() Random.se…

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## [Using ForwardDiff for Symbolic.derivative() definition](https://discourse.julialang.org/t/using-forwarddiff-for-symbolic-derivative-definition/123035)

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**Author:** [@anodos](https://discourse.julialang.org/u/anodos)\
**Replies:** 7\
**Last updated:** [November 26, 2024, 12:49pm UTC](https://discourse.julialang.org/t/using-forwarddiff-for-symbolic-derivative-definition/123035 "2024-11-26T12:49:20Z")

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I’ve only been playing with MTK.jl for a day or two, but I’m really impressed - the workflow here is so much nicer than using a dedicated acausal modelling language! I’m running into situations where judicious function r…

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## [Very slow performance when modifying and querying a model with JuMP](https://discourse.julialang.org/t/very-slow-performance-when-modifying-and-querying-a-model-with-jump/122842)

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**Author:** [@njozefow](https://discourse.julialang.org/u/njozefow)\
**Replies:** 4\
**Last updated:** [November 26, 2024, 10:56am UTC](https://discourse.julialang.org/t/very-slow-performance-when-modifying-and-querying-a-model-with-jump/122842 "2024-11-26T10:56:34Z")

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Hello, I have a question about the modifications and queries of a model with jump. If I use a jump model with set\_objective\_coefficient and set\_normalized\_coefficient, the computational times are 25 times slower than wi…

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## [Simulating membrane Julia](https://discourse.julialang.org/t/simulating-membrane-julia/123084)

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**Author:** [@Alma\_Thindberg](https://discourse.julialang.org/u/Alma_Thindberg)\
**Replies:** 0\
**Last updated:** [November 26, 2024, 9:36am UTC](https://discourse.julialang.org/t/simulating-membrane-julia/123084 "2024-11-26T09:36:10Z")

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using Pkg Pkg.add("ModelingToolkit") Pkg.add("MethodOfLines") Pkg.add("DomainSets") Pkg.add("OrdinaryDiffEq") using ModelingToolkit, MethodOfLines, DomainSets, OrdinaryDiffEq include("Properties2.jl") import ModelingTo…

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## [Problem setting constraint in simple LP using JuMP](https://discourse.julialang.org/t/problem-setting-constraint-in-simple-lp-using-jump/123059)

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**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 5\
**Last updated:** [November 26, 2024, 1:48am UTC](https://discourse.julialang.org/t/problem-setting-constraint-in-simple-lp-using-jump/123059 "2024-11-26T01:48:32Z")

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Hi there, Im trying to construct a simple LP using JuMP but I am running into an issue with the constraint in the function. I checked this is the line causing the issue since if I delete it, I can define the function in…

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## [Facility location problem](https://discourse.julialang.org/t/facility-location-problem/123068)

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**Author:** [@aditya\_lokesh](https://discourse.julialang.org/u/aditya_lokesh)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 1:39am UTC](https://discourse.julialang.org/t/facility-location-problem/123068 "2024-11-26T01:39:28Z")

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facing a issue with my implementation of the facility location problem. I tried implementing the problem however the optimization model just does not seem to stop even after 3 hours not sure if I have slow computer. n…

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## [Bode plot of DSP filter?](https://discourse.julialang.org/t/bode-plot-of-dsp-filter/122845)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [November 25, 2024, 7:48pm UTC](https://discourse.julialang.org/t/bode-plot-of-dsp-filter/122845 "2024-11-25T19:48:00Z")

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I designed a discrete Butterworth filter using the DSP package. How can I create a Bode plot of the transfer function? using DSP function create\_filter(cut\_off\_freq; order=4, type=:Butter, dt) if type == :Butter …

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## [Rand does not return expected confidence interval](https://discourse.julialang.org/t/rand-does-not-return-expected-confidence-interval/123053)

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**Author:** [@Trylmand](https://discourse.julialang.org/u/Trylmand)\
**Replies:** 2\
**Last updated:** [November 25, 2024, 7:02pm UTC](https://discourse.julialang.org/t/rand-does-not-return-expected-confidence-interval/123053 "2024-11-25T19:02:32Z")

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Dear all, Testing Rand() on MC algorithm for estimating integral of Sine from 0 to Pi, only returns 50% of the expected confidence interval. Can anybody see, where my code breaks? n = 1000 in\_ci = 0 for i in 1:500 …

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## [Spatial Join with GeometryOps is killing my Julia session](https://discourse.julialang.org/t/spatial-join-with-geometryops-is-killing-my-julia-session/122863)

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**Author:** [@alejandromerchan](https://discourse.julialang.org/u/alejandromerchan)\
**Replies:** 15\
**Last updated:** [November 25, 2024, 4:13pm UTC](https://discourse.julialang.org/t/spatial-join-with-geometryops-is-killing-my-julia-session/122863 "2024-11-25T16:13:03Z")

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I’m trying to perform a spatial join in Julia between two files that aren’t that large. One is the California PLSS sections shapefile, which is publicly available here and is 164627 x 17 after some cleaning. The other I …

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## [BifurcationKit: PeriodicOrbitOCollProblem Failure to converge with given tolerances](https://discourse.julialang.org/t/bifurcationkit-periodicorbitocollproblem-failure-to-converge-with-given-tolerances/123048)

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**Author:** [@mmplac14](https://discourse.julialang.org/u/mmplac14)\
**Replies:** 0\
**Last updated:** [November 25, 2024, 3:26pm UTC](https://discourse.julialang.org/t/bifurcationkit-periodicorbitocollproblem-failure-to-converge-with-given-tolerances/123048 "2024-11-25T15:26:10Z")

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Hello! I am new to bifurcation analyis and I am working with BifurcationKit to reproduce the bifurcation analysis performed by Grimbert Faugueras on the Jansen-Rit model. I have managed to get the continuation graph. …

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## [How to determine whether the rule of an DynamicalSystem instance is inplace?](https://discourse.julialang.org/t/how-to-determine-whether-the-rule-of-an-dynamicalsystem-instance-is-inplace/123041)

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**Author:** [@andreasmorr](https://discourse.julialang.org/u/andreasmorr)\
**Replies:** 2\
**Last updated:** [November 25, 2024, 8:59am UTC](https://discourse.julialang.org/t/how-to-determine-whether-the-rule-of-an-dynamicalsystem-instance-is-inplace/123041 "2024-11-25T08:59:01Z")

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I would like to define a function that takes a DynamicalSystem ds as an argument and computes the Jacobian of dynamic\_rule(ds) for further analysis. For this, it would be good to know whether dynamic\_rule(ds) returns an …

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## [Visualizing Electric Equipotentials](https://discourse.julialang.org/t/visualizing-electric-equipotentials/123023)

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**Author:** [@NonDairyNeutrino](https://discourse.julialang.org/u/NonDairyNeutrino)\
**Replies:** 0\
**Last updated:** [November 24, 2024, 7:29pm UTC](https://discourse.julialang.org/t/visualizing-electric-equipotentials/123023 "2024-11-24T19:29:21Z")

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Hey all, not a question this time, but rather I just wanted to share something I whipped up a little bit ago for my class on introductory electromagnetism. Basically, it’s a drop-in way to visualize the contour lines of…

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## [Updating Label value twice in the same Makie event handler](https://discourse.julialang.org/t/updating-label-value-twice-in-the-same-makie-event-handler/122918)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 3\
**Last updated:** [November 24, 2024, 3:04pm UTC](https://discourse.julialang.org/t/updating-label-value-twice-in-the-same-makie-event-handler/122918 "2024-11-24T15:04:13Z")

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in the MWE below, “start” is never displayed. is there a way to make it so? using GLMakie f = Figure() b = Button(f\[1,1\], label="foo") l = Label(f\[1,2\], "") on(b.clicks) do \_ l.text\[\] = "start" sleep(1) # lon…

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## [AD Troubles in Flux and Unusual Loss](https://discourse.julialang.org/t/ad-troubles-in-flux-and-unusual-loss/122995)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [November 24, 2024, 12:09am UTC](https://discourse.julialang.org/t/ad-troubles-in-flux-and-unusual-loss/122995 "2024-11-24T00:09:08Z")

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I’m struggling with the following issue. I want to train on a somewhat nonstandard loss function involving the gradient of the target. If everything worked, I would. use the following code: using Flux using Random usi…

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