# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=7

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**Page:** 8

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## [Compare two Turing models with LOO: SE is NaN](https://discourse.julialang.org/t/compare-two-turing-models-with-loo-se-is-nan/102269)

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**Author:** [@DominiqueMakowski](https://discourse.julialang.org/u/DominiqueMakowski)\
**Replies:** 7\
**Last updated:** [April 19, 2026, 1:17am UTC](https://discourse.julialang.org/t/compare-two-turing-models-with-loo-se-is-nan/102269 "2026-04-19T01:17:20Z")

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I am trying to compare two SequentialSamplingModels with loo using ParetoSmooth.jl, but I think I am doing something wrong: using Turing using SequentialSamplingModels using Random using Distributions using DataFrames u…

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## [MTK - structurally singular initialization?](https://discourse.julialang.org/t/mtk-structurally-singular-initialization/136771)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [April 18, 2026, 8:06pm UTC](https://discourse.julialang.org/t/mtk-structurally-singular-initialization/136771 "2026-04-18T20:06:40Z")

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I have a somewhat complex model constructed from my own components. Doing mtkcompile produces a system with 18 unknowns and 18 equations: 14 DEs and 4 AEs. When I create the ODEProblem, I am told: Warning: The initiali…

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## [90% of Ipopt run time is spent in Hessian/constraints evaluation, very little time in linear solver. Is it normal?](https://discourse.julialang.org/t/90-of-ipopt-run-time-is-spent-in-hessian-constraints-evaluation-very-little-time-in-linear-solver-is-it-normal/136708)

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**Author:** [@Ceserik](https://discourse.julialang.org/u/Ceserik)\
**Replies:** 11\
**Last updated:** [April 18, 2026, 7:55am UTC](https://discourse.julialang.org/t/90-of-ipopt-run-time-is-spent-in-hessian-constraints-evaluation-very-little-time-in-linear-solver-is-it-normal/136708 "2026-04-18T07:55:51Z")

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Hello, I have been trying to improve my solve time for nonlinear optimal control problem , it is a tool for solving minimum lap time for a race car GitHub - ceserik/SLapSim.jl: Scalable laptime simulator · GitHub. I am…

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## [Makie: how to make plotted elements be exactly up to figure edges](https://discourse.julialang.org/t/makie-how-to-make-plotted-elements-be-exactly-up-to-figure-edges/136750)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 3\
**Last updated:** [April 17, 2026, 5:56pm UTC](https://discourse.julialang.org/t/makie-how-to-make-plotted-elements-be-exactly-up-to-figure-edges/136750 "2026-04-17T17:56:25Z")

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This is the figure I am producing: but I want the left side of the plotted elements go up to exactly the very last pixel of the figure. I am not able to figure out how to achieve that. I am doing: t = 0:100 x = cos.…

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## [Update observables only when slider is released](https://discourse.julialang.org/t/update-observables-only-when-slider-is-released/136742)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 2\
**Last updated:** [April 17, 2026, 11:55am UTC](https://discourse.julialang.org/t/update-observables-only-when-slider-is-released/136742 "2026-04-17T11:55:39Z")

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For expensive computations, how can we slide on a Slider without triggering all intermediate values? One workaround is to add a separate Toggle to turn the computation on/off, but that adds unnecessary logic to the appli…

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## [SciML collocation BVP solvers overwrite the initial guess - bug or feature?](https://discourse.julialang.org/t/sciml-collocation-bvp-solvers-overwrite-the-initial-guess-bug-or-feature/136715)

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**Author:** [@ThermionicsGuy](https://discourse.julialang.org/u/ThermionicsGuy)\
**Replies:** 6\
**Last updated:** [April 16, 2026, 4:36pm UTC](https://discourse.julialang.org/t/sciml-collocation-bvp-solvers-overwrite-the-initial-guess-bug-or-feature/136715 "2026-04-16T16:36:37Z")

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I’ve encountered a behavior that I didn’t expect when solving BVPs with SciML collocation methods and using the continuation method. When you call “solve” and are using a previous solution object as the initial guess, th…

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## [\`legend\_groupclick = "toggleitem"\` doesn't seem to work in PlotlyJS](https://discourse.julialang.org/t/legend-groupclick-toggleitem-doesnt-seem-to-work-in-plotlyjs/76851)

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**Author:** [@Mo-Gul](https://discourse.julialang.org/u/Mo-Gul)\
**Replies:** 5\
**Last updated:** [April 16, 2026, 3:19pm UTC](https://discourse.julialang.org/t/legend-groupclick-toggleitem-doesnt-seem-to-work-in-plotlyjs/76851 "2026-04-16T15:19:48Z")

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Currently legend\_groupclick="toggleitem" doesn’t seem to work as can be tested in the result of using PlotlyJS function getData() x = range(start=0, stop=10, length=101) y1 = sin.(x) y2 = sin.(x) .- 0.1 …

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## [How to change the default colors of a series in Makie](https://discourse.julialang.org/t/how-to-change-the-default-colors-of-a-series-in-makie/136738)

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**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 0\
**Last updated:** [April 16, 2026, 12:54pm UTC](https://discourse.julialang.org/t/how-to-change-the-default-colors-of-a-series-in-makie/136738 "2026-04-16T12:54:00Z")

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I’ve found some information about using set\_theme!, but it’s still not clear to me what to do and I would love to find a code snippet. How do I change the default colors used to plot a series in Makie?

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## [Radiobuttons and checkboxes in Makie](https://discourse.julialang.org/t/radiobuttons-and-checkboxes-in-makie/95017)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 8\
**Last updated:** [April 16, 2026, 10:41am UTC](https://discourse.julialang.org/t/radiobuttons-and-checkboxes-in-makie/95017 "2026-04-16T10:41:44Z")

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How could I create radiobuttons and checkboxes in Makie?

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## [Bottleneck of JuMP](https://discourse.julialang.org/t/bottleneck-of-jump/136609)

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**Author:** [@ttx002000](https://discourse.julialang.org/u/ttx002000)\
**Replies:** 24\
**Last updated:** [April 15, 2026, 8:38pm UTC](https://discourse.julialang.org/t/bottleneck-of-jump/136609 "2026-04-15T20:38:55Z")

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I am solving a SDP problem using JuMP and the associated MosekTools. The basic pattern is this:\` NQ=9 Nk=9 nred=4 Dmatrix = Vector{Any}(undef, 3) Dmatrix\[1\] = Vector{Any}(undef, NQ) # uuuu channel Dmatr…

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## [Julia Bioinformatics Algorithms New Project](https://discourse.julialang.org/t/julia-bioinformatics-algorithms-new-project/135501)

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**Author:** [@Stergios\_Papadimitri](https://discourse.julialang.org/u/Stergios_Papadimitri)\
**Replies:** 6\
**Last updated:** [April 15, 2026, 3:31pm UTC](https://discourse.julialang.org/t/julia-bioinformatics-algorithms-new-project/135501 "2026-04-15T15:31:05Z")

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Hi all, I started to develop a project for the implementation in Julia of the algorithms of the book “Bioinformatics Algorithms: An active learning approach” of Pavel Pevzner et. all The project URL is: https dot sour…

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## [Area under a ROC Curve after a logistic regression](https://discourse.julialang.org/t/area-under-a-roc-curve-after-a-logistic-regression/121121)

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**Author:** [@mwsohn](https://discourse.julialang.org/u/mwsohn)\
**Replies:** 3\
**Last updated:** [April 14, 2026, 8:09pm UTC](https://discourse.julialang.org/t/area-under-a-roc-curve-after-a-logistic-regression/121121 "2026-04-14T20:09:03Z")

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I am trying to compute ROCAnalysis.jl package to compute the AUC value after a logistic regression. When I ran auc(roc(dep, pred)), where dep is the vector with original binary dependent variable and pred the predicted…

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## [Migrating CUDA.jl atomic operations to ParallelStencil.jl using Atomix.jl?](https://discourse.julialang.org/t/migrating-cuda-jl-atomic-operations-to-parallelstencil-jl-using-atomix-jl/136710)

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**Author:** [@Ludovic\_Dumoulin](https://discourse.julialang.org/u/Ludovic_Dumoulin)\
**Replies:** 2\
**Last updated:** [April 14, 2026, 1:57pm UTC](https://discourse.julialang.org/t/migrating-cuda-jl-atomic-operations-to-parallelstencil-jl-using-atomix-jl/136710 "2026-04-14T13:57:33Z")

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Hello, I am currently porting my code from CUDA.jl to ParallelStencil.jl. While I have successfully managed the transition for mixed Float64 and ComplexF64 types, I have run into a challenge replacing CUDA-specific atom…

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## [Zygote gradients around closures and objects with custom properties](https://discourse.julialang.org/t/zygote-gradients-around-closures-and-objects-with-custom-properties/136704)

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**Author:** [@goerz](https://discourse.julialang.org/u/goerz)\
**Replies:** 1\
**Last updated:** [April 13, 2026, 10:02pm UTC](https://discourse.julialang.org/t/zygote-gradients-around-closures-and-objects-with-custom-properties/136704 "2026-04-13T22:02:15Z")

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I have the following function: function make\_automatic\_xi(g\_b) function automatic\_xi(Ψ, trajectory, tlist, n) grad = Zygote.gradient(psi -\> g\_b(psi, trajectory, tlist, n), Ψ)\[1\] if isnothing(grad) …

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## [Vibe-coded modelingtoolkit code generation for PDEs](https://discourse.julialang.org/t/vibe-coded-modelingtoolkit-code-generation-for-pdes/136701)

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**Author:** [@ctessum](https://discourse.julialang.org/u/ctessum)\
**Replies:** 0\
**Last updated:** [April 13, 2026, 4:55pm UTC](https://discourse.julialang.org/t/vibe-coded-modelingtoolkit-code-generation-for-pdes/136701 "2026-04-13T16:55:53Z")

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The current released version of ModelingToolkit.jl + MethodOfLines.jl doesn’t really work when the number of variables x the number of grid points is more than ~1,000. In case it is of interest, I’ve created some vibe-c…

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## [New package for clustering - need for an arXiv endorser](https://discourse.julialang.org/t/new-package-for-clustering-need-for-an-arxiv-endorser/128983)

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**Author:** [@uwestoehr](https://discourse.julialang.org/u/uwestoehr)\
**Replies:** 3\
**Last updated:** [April 13, 2026, 2:30pm UTC](https://discourse.julialang.org/t/new-package-for-clustering-need-for-an-arxiv-endorser/128983 "2026-04-13T14:30:42Z")

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Hi I am Uwe, a MEMS engineer. During evaluation of some measurement data I had an idea for a clustering algorithm and started with Julia to be able to implement this algorithm as I had it in mind. That succeeded and the …

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## [Ribbon opacity when plotting multiple line in Plots.jl](https://discourse.julialang.org/t/ribbon-opacity-when-plotting-multiple-line-in-plots-jl/136643)

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**Author:** [@silveedee](https://discourse.julialang.org/u/silveedee)\
**Replies:** 4\
**Last updated:** [April 13, 2026, 1:18pm UTC](https://discourse.julialang.org/t/ribbon-opacity-when-plotting-multiple-line-in-plots-jl/136643 "2026-04-13T13:18:34Z")

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I have some lines I’m plotting that I want to add error bars too. Here’s an approximation of my data, and my first attempt to plot these lines with error bars s = 1:10:101 r = 0.0:0.1:1 rand\_error=rand(5:10,(11,11)) …

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## [Compiling Julia code for a RISC-V ESP32 microcontroller](https://discourse.julialang.org/t/compiling-julia-code-for-a-risc-v-esp32-microcontroller/135108)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 10\
**Last updated:** [April 13, 2026, 12:00pm UTC](https://discourse.julialang.org/t/compiling-julia-code-for-a-risc-v-esp32-microcontroller/135108 "2026-04-13T12:00:14Z")

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I wanted to share some experiments I did to run Julia on a ESP32 C3 using GPUCompiler and LLVM: This microcontrollers use the open RISC-V instruction set. The ESP32 family of microcontrollers are quite popular because…

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## [MTK Components: PDE boundary conditions?](https://discourse.julialang.org/t/mtk-components-pde-boundary-conditions/136689)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [April 12, 2026, 2:29pm UTC](https://discourse.julialang.org/t/mtk-components-pde-boundary-conditions/136689 "2026-04-12T14:29:50Z")

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I have a distributed pipe model connected to a hydraulic port with “potential” p (pressure), and mass flow rate as Flow. So with two PDEs (one in pressure, one in mass flow rate) + some AEs, what is the correct way to c…

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## [Does a very large number of observed variables (3207 vs 1188 equations) significantly increase ODEProblem memory?](https://discourse.julialang.org/t/does-a-very-large-number-of-observed-variables-3207-vs-1188-equations-significantly-increase-odeproblem-memory/136618)

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**Author:** [@chen\_hardworking](https://discourse.julialang.org/u/chen_hardworking)\
**Replies:** 2\
**Last updated:** [April 10, 2026, 7:57am UTC](https://discourse.julialang.org/t/does-a-very-large-number-of-observed-variables-3207-vs-1188-equations-significantly-increase-odeproblem-memory/136618 "2026-04-10T07:57:18Z")

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Hi SciML team and community, I’m developing PowerEMT.jl, an open-source Julia package for Electromagnetic Transient (EMT) simulation of large power systems using ModelingToolkit.jl, specifically for IBR-dominated power …

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## [Packages for mass spectrometry?](https://discourse.julialang.org/t/packages-for-mass-spectrometry/43481)

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**Author:** [@Eugeleo](https://discourse.julialang.org/u/Eugeleo)\
**Replies:** 14\
**Last updated:** [April 9, 2026, 8:55pm UTC](https://discourse.julialang.org/t/packages-for-mass-spectrometry/43481 "2026-04-09T20:55:45Z")

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My bachelor thesis concerns working mass spectrometry data; I’ll need to be able to load the spectra, visualise them, and most importantly, given a spectrum and a peptide fragment I’ll need to decide how likely it is tha…

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## [Makie menu and toggle color do not update when observable is changed](https://discourse.julialang.org/t/makie-menu-and-toggle-color-do-not-update-when-observable-is-changed/136626)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 1\
**Last updated:** [April 9, 2026, 3:01pm UTC](https://discourse.julialang.org/t/makie-menu-and-toggle-color-do-not-update-when-observable-is-changed/136626 "2026-04-09T15:01:20Z")

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in the MWE below, the slider and checkbox both change from red to blue, but the menu only does so if you then subsequently hover over it, and the toggle only if you toggle back and forth. i would’ve expected this to jus…

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## [InexactError in HomotopyContinuation.jl when solving a 5-body central configuration system](https://discourse.julialang.org/t/inexacterror-in-homotopycontinuation-jl-when-solving-a-5-body-central-configuration-system/136462)

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**Author:** [@xiaoming](https://discourse.julialang.org/u/xiaoming)\
**Replies:** 9\
**Last updated:** [April 9, 2026, 2:45pm UTC](https://discourse.julialang.org/t/inexacterror-in-homotopycontinuation-jl-when-solving-a-5-body-central-configuration-system/136462 "2026-04-09T14:45:36Z")

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I am trying to use HomotopyContinuation.jl to solve the central configuration problem. Below is a minimal working example of my code: using HomotopyContinuation, LinearAlgebra function gen\_equations(m) n = length(m)…

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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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## [Degree of Chebyshev polynomial off by one](https://discourse.julialang.org/t/degree-of-chebyshev-polynomial-off-by-one/136627)

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**Author:** [@CFBaptista](https://discourse.julialang.org/u/CFBaptista)\
**Replies:** 4\
**Last updated:** [April 8, 2026, 10:12pm UTC](https://discourse.julialang.org/t/degree-of-chebyshev-polynomial-off-by-one/136627 "2026-04-08T22:12:57Z")

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According to Wikipedia pages Chebyshev polynomials and Chebyshev nodes a Chebyshev polynomial of the first kind of degree n has n roots. However, in BarycentricInterpolation.jl I get: using BarycentricInterpolation no…

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## [Makie/Observable: \`@lift\` and type](https://discourse.julialang.org/t/makie-observable-lift-and-type/136597)

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**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\
**Replies:** 3\
**Last updated:** [April 7, 2026, 4:20pm UTC](https://discourse.julialang.org/t/makie-observable-lift-and-type/136597 "2026-04-07T16:20:01Z")

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Basically, I want to write my plotting functions in such a way that they work whether the arrays to be plotted are Observables or not. This enables me to use my snapshot-producing functions in creating movies. For this…

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## [Package for generalized special functions](https://discourse.julialang.org/t/package-for-generalized-special-functions/67076)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [April 5, 2026, 9:00pm UTC](https://discourse.julialang.org/t/package-for-generalized-special-functions/67076 "2026-04-05T21:00:57Z")

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Is there any package that implements “generalized” special functions like the Meijer G-function, Fox–Wright Psi-function, Fox H-function? My go to for this kind of needs GSL.jl doesn’t have them.

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## [Vertex Connectivity](https://discourse.julialang.org/t/vertex-connectivity/136573)

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**Author:** [@Pancake](https://discourse.julialang.org/u/Pancake)\
**Replies:** 2\
**Last updated:** [April 5, 2026, 6:17pm UTC](https://discourse.julialang.org/t/vertex-connectivity/136573 "2026-04-05T18:17:42Z")

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Hello Community, I am trying to find a way to calculate Vertex Connectivity, since I did not find a function from Graphs.jl. Unfortunately, I could not find a suitable way to implement it myself, since my background isn’…

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## [Is JuMP.@variable slow when the number gets large?](https://discourse.julialang.org/t/is-jump-variable-slow-when-the-number-gets-large/136430)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 12\
**Last updated:** [April 5, 2026, 12:47am UTC](https://discourse.julialang.org/t/is-jump-variable-slow-when-the-number-gets-large/136430 "2026-04-05T00:47:13Z")

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I have a Unit commitment (24 hours, 5000 scenarios, IEEE118) problem, that has these two lines @time JuMP.@variable(m, pA\[i=\_2(t,T,1), \_0(i,t,S), agi\]) @time JuMP.@variable(m, pf\[i=\_2(t,T,0), \_0(i,t,S), 1:size(F,1)\]) w…

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## [Can I create a null JuMP.VariableRef?](https://discourse.julialang.org/t/can-i-create-a-null-jump-variableref/136492)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 5\
**Last updated:** [April 3, 2026, 1:33am UTC](https://discourse.julialang.org/t/can-i-create-a-null-jump-variableref/136492 "2026-04-03T01:33:50Z")

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I can pre-allocate a JuMP.AffExpr(0.). But can I create a dumb x = JuMP.VariableRef(undef)? Then I can write something like v = JuMP.Containers.@container(\[i=1:3\], x) for i = 1:3 if i !== 3 v\[i\] = JuMP.@var…

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