# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=44

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**Page:** 45

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## [Type stability of destructure / re-build in Optimisers.jl](https://discourse.julialang.org/t/type-stability-of-destructure-re-build-in-optimisers-jl/128783)

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**Author:** [@FerreolS](https://discourse.julialang.org/u/FerreolS)\
**Replies:** 2\
**Last updated:** [May 7, 2025, 3:20pm UTC](https://discourse.julialang.org/t/type-stability-of-destructure-re-build-in-optimisers-jl/128783 "2025-05-07T15:20:49Z")

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Hi, Destructuring struct with destructure is very handy. Thank you. However I’m a bit surprise that the restructuring is not Type stable. Am I missing something? Does it have some impact on speed when re(flat) (and its…

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## [Estimate affine transformations between images](https://discourse.julialang.org/t/estimate-affine-transformations-between-images/128798)

<div class="topic-metadata">

**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 0\
**Last updated:** [May 7, 2025, 2:11pm UTC](https://discourse.julialang.org/t/estimate-affine-transformations-between-images/128798 "2025-05-07T14:11:40Z")

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Is there any package implementing Lucchese’s et al. algorithm to estimate the affine transformation between two images - or a similar algorithm that does not use image features, but the whole images? If not, would it be…

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## [Initial equations possible in MTK?](https://discourse.julialang.org/t/initial-equations-possible-in-mtk/128767)

<div class="topic-metadata">

**Author:** [@Matthew1](https://discourse.julialang.org/u/Matthew1)\
**Replies:** 1\
**Last updated:** [May 7, 2025, 10:56am UTC](https://discourse.julialang.org/t/initial-equations-possible-in-mtk/128767 "2025-05-07T10:56:35Z")

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As mentioned here \[MTK -- how to set initial unknowns introduced by MTK?\] and here \[GitHub · Where software is built\], there are many cases where it is helpful to specify initial equations, i.e. specifying initial values…

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## [Inner product grammar is neater than sum(index) in JuMP modeling, But triggers Warning?](https://discourse.julialang.org/t/inner-product-grammar-is-neater-than-sum-index-in-jump-modeling-but-triggers-warning/124528)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 28\
**Last updated:** [May 6, 2025, 2:34am UTC](https://discourse.julialang.org/t/inner-product-grammar-is-neater-than-sum-index-in-jump-modeling-but-triggers-warning/124528 "2025-05-06T02:34:44Z")

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Continuing the discussion from JuMP slow model generation: I figured out a novel neat way to write a particular kind of constraint, however it trigger warnings like the above post did. Can we somehow improve this? see …

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## [Fill a bounding box behind text in Makie](https://discourse.julialang.org/t/fill-a-bounding-box-behind-text-in-makie/101502)

<div class="topic-metadata">

**Author:** [@garrek](https://discourse.julialang.org/u/garrek)\
**Replies:** 8\
**Last updated:** [May 7, 2025, 6:16am UTC](https://discourse.julialang.org/t/fill-a-bounding-box-behind-text-in-makie/101502 "2025-05-07T06:16:07Z")

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Is there now a way to fill a text bounding box? This question was asked a couple of years ago, but there was not a direct implementation at that time and a lot has changed since then. Basically, what I’d like to do is h…

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## [Parquet2.jl](https://discourse.julialang.org/t/parquet2-jl/128639)

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**Author:** [@Sam\_P](https://discourse.julialang.org/u/Sam_P)\
**Replies:** 3\
**Last updated:** [May 6, 2025, 10:00pm UTC](https://discourse.julialang.org/t/parquet2-jl/128639 "2025-05-06T22:00:34Z")

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Hi all, just a quick question regarding Parquet2.jl. Love the package and it has been a life-saver more than once. However, when starting a new repo I noticed that it is blocking LazyArrays from updating. LazyArrays v1.…

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## [Robust control with CRONE controllers](https://discourse.julialang.org/t/robust-control-with-crone-controllers/128733)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [May 6, 2025, 3:36pm UTC](https://discourse.julialang.org/t/robust-control-with-crone-controllers/128733 "2025-05-06T15:36:59Z")

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Today I heard the first time about CRONE controllers. “The CRONE controller uses fractional-order calculus (non-integer order derivatives and integrals), offering more tuning flexibility and robustness, whereas tradition…

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## [UV mapping](https://discourse.julialang.org/t/uv-mapping/128720)

<div class="topic-metadata">

**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 4\
**Last updated:** [May 6, 2025, 12:58pm UTC](https://discourse.julialang.org/t/uv-mapping/128720 "2025-05-06T12:58:27Z")

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Hi, is there any package that does (or can help in doing) UV mapping? More specifically: I have a 3D mesh made of triangles, and I want to “unwrap it” mapping each of its 3D points to a 2D plane.

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## [Specifying the Hessian for some (but not all) user-defined operators](https://discourse.julialang.org/t/specifying-the-hessian-for-some-but-not-all-user-defined-operators/128741)

<div class="topic-metadata">

**Author:** [@franckgaga](https://discourse.julialang.org/u/franckgaga)\
**Replies:** 2\
**Last updated:** [May 6, 2025, 11:41am UTC](https://discourse.julialang.org/t/specifying-the-hessian-for-some-but-not-all-user-defined-operators/128741 "2025-05-06T11:41:35Z")

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In ModelPredictiveControl.jl, I build the nonlinear optimization problem of NonLinMPC using multiple user-defined operators in JuMP.jl. One operator is for the objective function, the other operators appear in the nonlin…

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## [Nested task exception while using Cbc (COIN-OR Branch and Cut) solver inside SDDP.jl](https://discourse.julialang.org/t/nested-task-exception-while-using-cbc-coin-or-branch-and-cut-solver-inside-sddp-jl/128683)

<div class="topic-metadata">

**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 4\
**Last updated:** [May 5, 2025, 7:17pm UTC](https://discourse.julialang.org/t/nested-task-exception-while-using-cbc-coin-or-branch-and-cut-solver-inside-sddp-jl/128683 "2025-05-05T19:17:40Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve the stage-wise problem instances using the Cbc (and other solvers) within the SDDiP algorithm using the S…

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## [Questions about Cholesky and QR factorizations](https://discourse.julialang.org/t/questions-about-cholesky-and-qr-factorizations/128728)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 1\
**Last updated:** [May 5, 2025, 3:58pm UTC](https://discourse.julialang.org/t/questions-about-cholesky-and-qr-factorizations/128728 "2025-05-05T15:58:14Z")

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I’ve learned that. (But the title of the topic is very general, which is tempting for people to discuss things.) But I find that I cannot perform U \\ UQ (see the 🟠 line) due to ERROR: MethodError: no method matching /…

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## [How to license Gurobi inside Google Colab's Julia environment](https://discourse.julialang.org/t/how-to-license-gurobi-inside-google-colabs-julia-environment/128407)

<div class="topic-metadata">

**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 7\
**Last updated:** [May 5, 2025, 12:50pm UTC](https://discourse.julialang.org/t/how-to-license-gurobi-inside-google-colabs-julia-environment/128407 "2025-05-05T12:50:50Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve the stage-wise problem instances using the Gurobi solver within SDDiP algorithm using the SDDP.jl packag…

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## [How to set tolerance attributes of Gurobi inside Google Colab’s Julia environment](https://discourse.julialang.org/t/how-to-set-tolerance-attributes-of-gurobi-inside-google-colab-s-julia-environment/128678)

<div class="topic-metadata">

**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 6\
**Last updated:** [May 5, 2025, 12:47pm UTC](https://discourse.julialang.org/t/how-to-set-tolerance-attributes-of-gurobi-inside-google-colab-s-julia-environment/128678 "2025-05-05T12:47:08Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve the stage-wise problem instances using the Gurobi solver within SDDiP algorithm using the SDDP.jl packag…

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## [Is there a way to extract the number of mixed-integer iterations during a particular iteration or solve in the SDDP.jl?](https://discourse.julialang.org/t/is-there-a-way-to-extract-the-number-of-mixed-integer-iterations-during-a-particular-iteration-or-solve-in-the-sddp-jl/128702)

<div class="topic-metadata">

**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 2\
**Last updated:** [May 5, 2025, 12:46pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-extract-the-number-of-mixed-integer-iterations-during-a-particular-iteration-or-solve-in-the-sddp-jl/128702 "2025-05-05T12:46:19Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve it using the SDDiP algorithm using the SDDP.jl package in Julia. In this regard, I want to determine th…

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## [Saving Codim-2 data](https://discourse.julialang.org/t/saving-codim-2-data/128564)

<div class="topic-metadata">

**Author:** [@iclo3](https://discourse.julialang.org/u/iclo3)\
**Replies:** 2\
**Last updated:** [May 5, 2025, 9:28am UTC](https://discourse.julialang.org/t/saving-codim-2-data/128564 "2025-05-05T09:28:59Z")

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Hi, I want to save the output of my Codim-2 continuation as a csv or txt file. codim2\_a2 = continuation(br, 2, (@optic \_.a2), ContinuationPar(opts\_br, p\_min = 0.0, p\_max = 1000.0, dsmin = 1e-6, max\_steps = 1e8, tol…

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## [Error when running Code on GPU](https://discourse.julialang.org/t/error-when-running-code-on-gpu/128711)

<div class="topic-metadata">

**Author:** [@Efstein](https://discourse.julialang.org/u/Efstein)\
**Replies:** 0\
**Last updated:** [May 5, 2025, 8:47am UTC](https://discourse.julialang.org/t/error-when-running-code-on-gpu/128711 "2025-05-05T08:47:17Z")

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Hi everybody! I am still quite new to Julia, so I hope I’m not missing something obvious. My goal is to solve a system of chemical equations with NeuralPDE. This runs fine, although very slow, on the CPU, but when I try…

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## [Missing EXIF data when using ImageMagick.jl](https://discourse.julialang.org/t/missing-exif-data-when-using-imagemagick-jl/92519)

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**Author:** [@albrightand](https://discourse.julialang.org/u/albrightand)\
**Replies:** 1\
**Last updated:** [May 5, 2025, 12:22am UTC](https://discourse.julialang.org/t/missing-exif-data-when-using-imagemagick-jl/92519 "2025-05-05T00:22:59Z")

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I’m trying to use ImageMagick.jl to read EXIF GPS data from some .tif files. info = magickinfo(filename) provides a vector of image properties, but the GPS data is not included. When I look at the image properties manua…

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## [Type-stable function with Flux Chain and Dense](https://discourse.julialang.org/t/type-stable-function-with-flux-chain-and-dense/128689)

<div class="topic-metadata">

**Author:** [@bienpierre](https://discourse.julialang.org/u/bienpierre)\
**Replies:** 3\
**Last updated:** [May 4, 2025, 9:00pm UTC](https://discourse.julialang.org/t/type-stable-function-with-flux-chain-and-dense/128689 "2025-05-04T21:00:22Z")

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Dear All, I’m trying to make the following function containing Flux Chain and Dense type stable. using Flux @kwdef mutable struct Fnn{T \<: Function} neuron::Int = 5 layer::Int = 3 σ::T = Flux.relu end fu…

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## [Indexing of Symbolic Arrays (Arr{Num,3}) not working when a guess is provided in MTK](https://discourse.julialang.org/t/indexing-of-symbolic-arrays-arr-num-3-not-working-when-a-guess-is-provided-in-mtk/128631)

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**Author:** [@sass-jacob](https://discourse.julialang.org/u/sass-jacob)\
**Replies:** 2\
**Last updated:** [May 4, 2025, 4:53pm UTC](https://discourse.julialang.org/t/indexing-of-symbolic-arrays-arr-num-3-not-working-when-a-guess-is-provided-in-mtk/128631 "2025-05-04T16:53:04Z")

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Hello, I have created a MWE where the indexing of symbolic arrays begins to fail when I provide an initial guess for the variables as data for MTK. If I remove the guess, the indexing works fine. Edit, more info: if th…

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## [Acausal Modelling and Control Sytem](https://discourse.julialang.org/t/acausal-modelling-and-control-sytem/127003)

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**Author:** [@AndhikaTama](https://discourse.julialang.org/u/AndhikaTama)\
**Replies:** 22\
**Last updated:** [May 4, 2025, 3:39pm UTC](https://discourse.julialang.org/t/acausal-modelling-and-control-sytem/127003 "2025-05-04T15:39:55Z")

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Hello everyone, I am a new user of Julia ModelingToolkit and ControlSystem. I am currently working on a project with the topic Nonlinear Dynamic Simulation of a MicroGas Turbine Integrated with Concentrated Solar Therma…

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## [Slighly different results for conduction-advection with Neuman boundary conditions: Crank-Nicolson VS. Method of Lines](https://discourse.julialang.org/t/slighly-different-results-for-conduction-advection-with-neuman-boundary-conditions-crank-nicolson-vs-method-of-lines/128488)

<div class="topic-metadata">

**Author:** [@David\_F](https://discourse.julialang.org/u/David_F)\
**Replies:** 1\
**Last updated:** [May 4, 2025, 7:31am UTC](https://discourse.julialang.org/t/slighly-different-results-for-conduction-advection-with-neuman-boundary-conditions-crank-nicolson-vs-method-of-lines/128488 "2025-05-04T07:31:57Z")

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INTRO: Heat conduction + advection problem… 1D spherical coordinates. For Dirichlet BC (bc\_left\_type = “Dirichlet” and bc\_right\_type = “Dirichlet”), the two codes (CN and MOL) return identical results up to machine prec…

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## [Empty plot with colorbar and colorbar width](https://discourse.julialang.org/t/empty-plot-with-colorbar-and-colorbar-width/128673)

<div class="topic-metadata">

**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 3\
**Last updated:** [May 3, 2025, 8:18pm UTC](https://discourse.julialang.org/t/empty-plot-with-colorbar-and-colorbar-width/128673 "2025-05-03T20:18:08Z")

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I’m using Plots with GR Is it possible to make empty plot with colorbar? I try: plot(;colorbar=true, clims = (-0.05, 0.05),c = cg, zcolor = 1) colorbar - not displayed. Is it possible to change width of colorbar?

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## [Attributes (in particular width) of the colorbar in Plots.jl](https://discourse.julialang.org/t/attributes-in-particular-width-of-the-colorbar-in-plots-jl/32225)

<div class="topic-metadata">

**Author:** [@rad1um](https://discourse.julialang.org/u/rad1um)\
**Replies:** 4\
**Last updated:** [May 3, 2025, 8:24pm UTC](https://discourse.julialang.org/t/attributes-in-particular-width-of-the-colorbar-in-plots-jl/32225 "2025-05-03T20:24:39Z")

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How do I change the attributes of the colorbar in Plots? In particular I would like to change the width and change the location, s.t. it is directly next to the corresponding plot. Thanks in advance.

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## [Fastest way to sample from MVN, changing parameters](https://discourse.julialang.org/t/fastest-way-to-sample-from-mvn-changing-parameters/128145)

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**Author:** [@Daniel\_Johansson](https://discourse.julialang.org/u/Daniel_Johansson)\
**Replies:** 7\
**Last updated:** [May 3, 2025, 4:11pm UTC](https://discourse.julialang.org/t/fastest-way-to-sample-from-mvn-changing-parameters/128145 "2025-05-03T16:11:23Z")

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Hey guys! Does anybody know what is the most efficient way of sampling from a multivariate normal distribution whose parameters are constantly updated. I’m constructing a Gibbs sampler for a MVN whose parameters depend …

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## [Error when a neural ode is implemented](https://discourse.julialang.org/t/error-when-a-neural-ode-is-implemented/119963)

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**Author:** [@Ashima\_Kalathingal](https://discourse.julialang.org/u/Ashima_Kalathingal)\
**Replies:** 3\
**Last updated:** [May 2, 2025, 8:09pm UTC](https://discourse.julialang.org/t/error-when-a-neural-ode-is-implemented/119963 "2025-05-02T20:09:03Z")

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I am trying to implement a neural ode in Julia. The loss function reduces when training. But after the training the parameters are not updated. It goes back to initial value. When I run the algorithm the following error…

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## [Mapping Julia’s Astronomy Package Ecosystem: Bridging Gaps and Highlighting Strengths](https://discourse.julialang.org/t/mapping-julia-s-astronomy-package-ecosystem-bridging-gaps-and-highlighting-strengths/128249)

<div class="topic-metadata">

**Author:** [@The\_Mastermage](https://discourse.julialang.org/u/The_Mastermage)\
**Replies:** 47\
**Last updated:** [May 1, 2025, 9:27pm UTC](https://discourse.julialang.org/t/mapping-julia-s-astronomy-package-ecosystem-bridging-gaps-and-highlighting-strengths/128249 "2025-05-01T21:27:58Z")

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Hi all, I came across comment in the recent discussion on increasing Julia’s adoption. This raises an important point for anyone interested in Julia’s role in astronomy: even when the technical benefits are clear, ad…

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## [Debugging MTK with residuals](https://discourse.julialang.org/t/debugging-mtk-with-residuals/128616)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 1\
**Last updated:** [May 2, 2025, 12:38pm UTC](https://discourse.julialang.org/t/debugging-mtk-with-residuals/128616 "2025-05-02T12:38:22Z")

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I have some ModelingToolkit simulation that yields dubious results. No numerical error; just some quantity that becomes negative when it shouldn’t. I have to assume that one of my equations is wrong. Perhaps there is a c…

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## [Predict values using multinomial logistic regression?](https://discourse.julialang.org/t/predict-values-using-multinomial-logistic-regression/128621)

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**Author:** [@Paulogcd](https://discourse.julialang.org/u/Paulogcd)\
**Replies:** 1\
**Last updated:** [May 2, 2025, 11:39am UTC](https://discourse.julialang.org/t/predict-values-using-multinomial-logistic-regression/128621 "2025-05-02T11:39:16Z")

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Dear Julia community :slightly\_smiling\_face:, I have been trying to run a Multinomial logistic regression and to get the estimated results from a certain set of values. I managed to run the regression, but fail to get …

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## [How to incorporate state-dependent state constraint in JuMP](https://discourse.julialang.org/t/how-to-incorporate-state-dependent-state-constraint-in-jump/128485)

<div class="topic-metadata">

**Author:** [@stepanoslejsek](https://discourse.julialang.org/u/stepanoslejsek)\
**Replies:** 9\
**Last updated:** [May 2, 2025, 9:33am UTC](https://discourse.julialang.org/t/how-to-incorporate-state-dependent-state-constraint-in-jump/128485 "2025-05-02T09:33:18Z")

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Hi, I am trying to implement energy-efficient optimal control for vehicles, which includes traffic lights in the setup. The following problem is described as: \\text{minimize}\_{u^+, u^-} \\int\_{0}^{S} \\frac{u^+}{\\eta\_1} …

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## [Functionality like tidyverse's any\_of()?](https://discourse.julialang.org/t/functionality-like-tidyverses-any-of/128293)

<div class="topic-metadata">

**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 2\
**Last updated:** [May 1, 2025, 2:30pm UTC](https://discourse.julialang.org/t/functionality-like-tidyverses-any-of/128293 "2025-05-01T14:30:36Z")

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Is there any way to achieve functionality like tidyverse’s any\_of()? My use case is that I am reading only certain columns of a file, but there could be columns specified in the call, but non-existent in the file: vars…

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