# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=155

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**Page:** 156

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## [How to calculate the nearest point on a line to a given point](https://discourse.julialang.org/t/how-to-calculate-the-nearest-point-on-a-line-to-a-given-point/105743)

<div class="topic-metadata">

**Author:** [@Chamika\_Kasun](https://discourse.julialang.org/u/Chamika_Kasun)\
**Replies:** 16\
**Last updated:** [November 7, 2023, 11:45am UTC](https://discourse.julialang.org/t/how-to-calculate-the-nearest-point-on-a-line-to-a-given-point/105743 "2023-11-07T11:45:59Z")

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I’ve a line string that has long/lat coordinates as follows: \[ \[ 146.54294815408372, -36.04985956921628 \], \[ 146.5457684472937, -36.049249881…

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## [Novel method for feature importance using ReverseMode + ForwardMode autodiff?](https://discourse.julialang.org/t/novel-method-for-feature-importance-using-reversemode-forwardmode-autodiff/105837)

<div class="topic-metadata">

**Author:** [@nielsls](https://discourse.julialang.org/u/nielsls)\
**Replies:** 4\
**Last updated:** [November 7, 2023, 8:04am UTC](https://discourse.julialang.org/t/novel-method-for-feature-importance-using-reversemode-forwardmode-autodiff/105837 "2023-11-07T08:04:33Z")

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Using a combination of reverse- and forward-mode autodiff I have come across a highly efficient method for attributing the change in a differentiable scalar-valued function f: R^N-\>R^1 (e.g. a neural network) to the inpu…

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## [Molly.jl: AD with Enyzme returns 0 gradient](https://discourse.julialang.org/t/molly-jl-ad-with-enyzme-returns-0-gradient/105835)

<div class="topic-metadata">

**Author:** [@dan\_k](https://discourse.julialang.org/u/dan_k)\
**Replies:** 4\
**Last updated:** [November 7, 2023, 3:48am UTC](https://discourse.julialang.org/t/molly-jl-ad-with-enyzme-returns-0-gradient/105835 "2023-11-07T03:48:34Z")

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I am trying to use Enzyme.jl with Molly.jl to differentiate a MD Simulation with respect to some parameters. Unfortunately my program returns only gradients of magnitude 0. ( This has also been posted to Molly.jl: AD wi…

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## [Piecewise function as a constraint on Julia JuMP](https://discourse.julialang.org/t/piecewise-function-as-a-constraint-on-julia-jump/105854)

<div class="topic-metadata">

**Author:** [@Jesper](https://discourse.julialang.org/u/Jesper)\
**Replies:** 1\
**Last updated:** [November 6, 2023, 8:56pm UTC](https://discourse.julialang.org/t/piecewise-function-as-a-constraint-on-julia-jump/105854 "2023-11-06T20:56:39Z")

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I have an optimization model to which I need to add the following piecewise function as a constraint: C\_{i,k} = { PR\_{i} \* HSE\_{k} i∈Ω, k = 1,…,M , 1 i∈Ω, k = 1,…,M (otherwise) I read PR and HSE from excel cells ¿Is …

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## [Website generated by Franklin (and hosted on GitHub) is not rendering properly](https://discourse.julialang.org/t/website-generated-by-franklin-and-hosted-on-github-is-not-rendering-properly/105827)

<div class="topic-metadata">

**Author:** [@eduardo-zambrano](https://discourse.julialang.org/u/eduardo-zambrano)\
**Replies:** 10\
**Last updated:** [November 6, 2023, 7:49pm UTC](https://discourse.julialang.org/t/website-generated-by-franklin-and-hosted-on-github-is-not-rendering-properly/105827 "2023-11-06T19:49:39Z")

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Hi everyone, I have a website made with Franklin that looks good locally. Unfortunately, the one that is deployed through gh-pages on GitHub is missing most of the formatting, plus the links to the other parts of the we…

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## [\[suggestions\] A Way to find fixed points of coupledODE with a parameter that's sqrt function](https://discourse.julialang.org/t/suggestions-a-way-to-find-fixed-points-of-coupledode-with-a-parameter-thats-sqrt-function/105858)

<div class="topic-metadata">

**Author:** [@hisacro](https://discourse.julialang.org/u/hisacro)\
**Replies:** 6\
**Last updated:** [November 6, 2023, 7:16pm UTC](https://discourse.julialang.org/t/suggestions-a-way-to-find-fixed-points-of-coupledode-with-a-parameter-thats-sqrt-function/105858 "2023-11-06T19:16:28Z")

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Hello I’m trying to find fixed points of 2 coupled oscillator and one of the parameter is defined as sqrt (function of phase space variables) here’s the exact system, using DynamicalSystems, Plots, ChaosTools function…

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## [Differentiable image values of a triangle](https://discourse.julialang.org/t/differentiable-image-values-of-a-triangle/105821)

<div class="topic-metadata">

**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 3\
**Last updated:** [November 5, 2023, 8:43pm UTC](https://discourse.julialang.org/t/differentiable-image-values-of-a-triangle/105821 "2023-11-05T20:43:37Z")

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I have a 2D gray and white image and set of coordinates of triangles (generally all of the image is triangluted) is there a differentiable stable way to get mean and variance of the part of the image enclosed by each tr…

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## [Django/mezzanine like example with genie?](https://discourse.julialang.org/t/django-mezzanine-like-example-with-genie/71083)

<div class="topic-metadata">

**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 6\
**Last updated:** [November 6, 2023, 2:28pm UTC](https://discourse.julialang.org/t/django-mezzanine-like-example-with-genie/71083 "2023-11-06T14:28:06Z")

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Hi, I am considering porting a website from python to Julia. I have a django/mezzanine website which is dynamic (login, admin backend, backend for building pages, users gestion…) and I am looking for something similar i…

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## [Q: Symbolics.jl | How to convert symbolic multivariate polynomial to DynamicPolynomials type?](https://discourse.julialang.org/t/q-symbolics-jl-how-to-convert-symbolic-multivariate-polynomial-to-dynamicpolynomials-type/105618)

<div class="topic-metadata">

**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 4\
**Last updated:** [November 5, 2023, 3:29am UTC](https://discourse.julialang.org/t/q-symbolics-jl-how-to-convert-symbolic-multivariate-polynomial-to-dynamicpolynomials-type/105618 "2023-11-05T03:29:16Z")

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Hello, How would one go about converting symbolic multivariate polynomials generated in Symbolics.jl to DynamicPolynomials.jl type? The end goal is fast numerical evaluation of multivariate polynomials using FixedPol…

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## [DifferentialEquations & DynamicalSystems: Converting output Vector{Vector{Float64}} to StateSpaceSet](https://discourse.julialang.org/t/differentialequations-dynamicalsystems-converting-output-vector-vector-float64-to-statespaceset/105793)

<div class="topic-metadata">

**Author:** [@MvanSteenbergen](https://discourse.julialang.org/u/MvanSteenbergen)\
**Replies:** 2\
**Last updated:** [November 6, 2023, 3:06am UTC](https://discourse.julialang.org/t/differentialequations-dynamicalsystems-converting-output-vector-vector-float64-to-statespaceset/105793 "2023-11-06T03:06:34Z")

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I edited the post and added my steps below Hey, I am having compatibility issues with the DynamicalSystems and DifferentialEquations packages. I have implemented the following rule set using the DifferentialEquations …

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## [DiscreteCallback does not trigger as expected](https://discourse.julialang.org/t/discretecallback-does-not-trigger-as-expected/105816)

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**Author:** [@christianhvejsel](https://discourse.julialang.org/u/christianhvejsel)\
**Replies:** 6\
**Last updated:** [November 5, 2023, 8:21pm UTC](https://discourse.julialang.org/t/discretecallback-does-not-trigger-as-expected/105816 "2023-11-05T20:21:46Z")

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I am testing whether DiscreteCallback could be used instead of ContinuousCallback. For testing purposes I modified the ContinuousCallback bouncing ball example from the documentation: Bouncing ball ContinuousCallback exa…

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## [Battling Tableau at Work](https://discourse.julialang.org/t/battling-tableau-at-work/105804)

<div class="topic-metadata">

**Author:** [@merlin](https://discourse.julialang.org/u/merlin)\
**Replies:** 8\
**Last updated:** [November 5, 2023, 8:18pm UTC](https://discourse.julialang.org/t/battling-tableau-at-work/105804 "2023-11-05T20:18:02Z")

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At my mid-sized US tech company we are adopting more and more of the Tableau ecosystem. Not just the notebooks or server, but there is a cloud service and I was surprised to learn some form of orchestration and data pipe…

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## [Writting runge-kutta stages as an array of expression](https://discourse.julialang.org/t/writting-runge-kutta-stages-as-an-array-of-expression/105817)

<div class="topic-metadata">

**Author:** [@lieskjur](https://discourse.julialang.org/u/lieskjur)\
**Replies:** 2\
**Last updated:** [November 5, 2023, 7:24pm UTC](https://discourse.julialang.org/t/writting-runge-kutta-stages-as-an-array-of-expression/105817 "2023-11-05T19:24:39Z")

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Hi, I am writting a trajectory optimization scheme and for very specific reasons I want to constrain the change from state x\_j to x\_{j+1} to be a step of a runge-kutta method (I know multi-step methods would be more suit…

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## [How to find the best match for one image from an image set?](https://discourse.julialang.org/t/how-to-find-the-best-match-for-one-image-from-an-image-set/102705)

<div class="topic-metadata">

**Author:** [@RunguangLi](https://discourse.julialang.org/u/RunguangLi)\
**Replies:** 12\
**Last updated:** [November 5, 2023, 3:44pm UTC](https://discourse.julialang.org/t/how-to-find-the-best-match-for-one-image-from-an-image-set/102705 "2023-11-05T15:44:42Z")

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Hi, I’m trying to find the best match for one image from an image set. Currently I use assess\_ssim function to do it. For example, img2 is clearly the best match for img1. But assess\_ssim gives very similar estimates for…

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## [Anyone developing anything for Julia regarding SPH?](https://discourse.julialang.org/t/anyone-developing-anything-for-julia-regarding-sph/23708)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 7\
**Last updated:** [November 4, 2023, 6:03pm UTC](https://discourse.julialang.org/t/anyone-developing-anything-for-julia-regarding-sph/23708 "2023-11-04T18:03:42Z")

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Where SPH, stands for Smoothed Particle Hydrodynamics. Does anyone happen to have a special interest in the field or done something in Julia regarding this methodology? Kind regards

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## [Multi-objective MINLP problem in JuMP](https://discourse.julialang.org/t/multi-objective-minlp-problem-in-jump/103117)

<div class="topic-metadata">

**Author:** [@ashefa](https://discourse.julialang.org/u/ashefa)\
**Replies:** 38\
**Last updated:** [November 4, 2023, 8:44am UTC](https://discourse.julialang.org/t/multi-objective-minlp-problem-in-jump/103117 "2023-11-04T08:44:23Z")

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In the continuation of this comment and this post, I was wondering about the implementation of a multi-objective MINLP problem in JuMP using MOA. Since @Arpit\_Bhatia used MOA for a nonlinear multi-objective portfolio op…

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## [Peculiar GPU behavior: zero performance cost for math functions?](https://discourse.julialang.org/t/peculiar-gpu-behavior-zero-performance-cost-for-math-functions/105764)

<div class="topic-metadata">

**Author:** [@bremez](https://discourse.julialang.org/u/bremez)\
**Replies:** 5\
**Last updated:** [November 4, 2023, 4:24am UTC](https://discourse.julialang.org/t/peculiar-gpu-behavior-zero-performance-cost-for-math-functions/105764 "2023-11-04T04:24:15Z")

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I have a use case where the performance bottleneck is in computing trigonometric functions. I thought that maybe it would benefit from some more parallelism, and realized that having access to a university computing clus…

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## [Different visual types for different y axis variables](https://discourse.julialang.org/t/different-visual-types-for-different-y-axis-variables/105771)

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**Author:** [@gsinha](https://discourse.julialang.org/u/gsinha)\
**Replies:** 0\
**Last updated:** [November 3, 2023, 7:41pm UTC](https://discourse.julialang.org/t/different-visual-types-for-different-y-axis-variables/105771 "2023-11-03T19:41:34Z")

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How would I get y to be a scatter and yhat to be a scatterline in the following statement? data(df) \* mapping(:x, \[y, yhat\], color = dims(1) =\> renamer(\["Actual", "Predicted"\])) |\> draw;

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## [Kernel random numbers generation entropy / randomness issues](https://discourse.julialang.org/t/kernel-random-numbers-generation-entropy-randomness-issues/105637)

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**Author:** [@ReWoP](https://discourse.julialang.org/u/ReWoP)\
**Replies:** 25\
**Last updated:** [November 3, 2023, 4:19pm UTC](https://discourse.julialang.org/t/kernel-random-numbers-generation-entropy-randomness-issues/105637 "2023-11-03T16:19:05Z")

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Hi all! I’m implementing with some algorithms in the GPU (CUDA) that are stochastic in nature, meaning that they rely on random numbers (namely uniformly distributed random numbers in \[0,1\]) to achieve results. When pr…

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## [Coherence between signals](https://discourse.julialang.org/t/coherence-between-signals/102772)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 14\
**Last updated:** [November 3, 2023, 2:09pm UTC](https://discourse.julialang.org/t/coherence-between-signals/102772 "2023-11-03T14:09:17Z")

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I have two signals, lets call them U\_1 and U\_2. Both are time series of wind speeds, measured at different locations. They are more or less coherent. What I would like to know is how does the coherence between these sign…

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## [Looking for an Exact LP Solver](https://discourse.julialang.org/t/looking-for-an-exact-lp-solver/105696)

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**Author:** [@isaac.rubberducky](https://discourse.julialang.org/u/isaac.rubberducky)\
**Replies:** 8\
**Last updated:** [November 3, 2023, 1:48pm UTC](https://discourse.julialang.org/t/looking-for-an-exact-lp-solver/105696 "2023-11-03T13:48:36Z")

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I have an algorithm that iteratively runs an LP until a stability condition is met. It is guaranteed to stabilize in theory, and in practice it almost always does as well. However, sometimes the rounding error generated …

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## [Scale Division in Makie](https://discourse.julialang.org/t/scale-division-in-makie/105650)

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**Author:** [@vivekag7](https://discourse.julialang.org/u/vivekag7)\
**Replies:** 1\
**Last updated:** [November 1, 2023, 1:17pm UTC](https://discourse.julialang.org/t/scale-division-in-makie/105650 "2023-11-01T13:17:27Z")

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Hi, I was wondering if there is a way to put a scale division in a heatmap plot using Makie. See the following plot as a reference, where I would like to implement both the line and the value in the corner that is positi…

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## [Wram start of HermitianPSDCone in JuMP](https://discourse.julialang.org/t/wram-start-of-hermitianpsdcone-in-jump/105491)

<div class="topic-metadata">

**Author:** [@akirakyle](https://discourse.julialang.org/u/akirakyle)\
**Replies:** 11\
**Last updated:** [November 2, 2023, 10:14pm UTC](https://discourse.julialang.org/t/wram-start-of-hermitianpsdcone-in-jump/105491 "2023-11-02T22:14:43Z")

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I’m having trouble figuring out how to use set\_start\_value with HermitianPSDCone. Here’s a minimal script based on the the quantum discrimination example in the docs: using JuMP using LinearAlgebra import COSMO ρs = \[…

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## [Storing and importing structure containing a PyObject](https://discourse.julialang.org/t/storing-and-importing-structure-containing-a-pyobject/105711)

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**Author:** [@vivekag7](https://discourse.julialang.org/u/vivekag7)\
**Replies:** 2\
**Last updated:** [November 2, 2023, 7:38pm UTC](https://discourse.julialang.org/t/storing-and-importing-structure-containing-a-pyobject/105711 "2023-11-02T19:38:25Z")

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So I want to store a structure called Results which contains the following: (:rgi\_id, :H, :S, :B, :V, :Vx, :Vy, :Δx, :Δy, :gdir) Where :H, :S, :B, :V, :Vx, :Vy, are 2D matrices :rgi\_id, is a string :Δx, :Δy, are floa…

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## [ModelingToolkit | Error with uncertain parameters using Measurements.jl](https://discourse.julialang.org/t/modelingtoolkit-error-with-uncertain-parameters-using-measurements-jl/105701)

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**Author:** [@fabianmueller](https://discourse.julialang.org/u/fabianmueller)\
**Replies:** 7\
**Last updated:** [November 2, 2023, 6:46pm UTC](https://discourse.julialang.org/t/modelingtoolkit-error-with-uncertain-parameters-using-measurements-jl/105701 "2023-11-02T18:46:22Z")

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Hello! :slight\_smile: Lately I am always getting an error when simulating a ModelingToolkit.jl model with uncertain parameters from Measurements.jl. I have the feeling that this worked before and the error especially ca…

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## [Geometric Constraints and Collision Detection](https://discourse.julialang.org/t/geometric-constraints-and-collision-detection/105695)

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**Author:** [@InesP](https://discourse.julialang.org/u/InesP)\
**Replies:** 0\
**Last updated:** [November 2, 2023, 12:20pm UTC](https://discourse.julialang.org/t/geometric-constraints-and-collision-detection/105695 "2023-11-02T12:20:13Z")

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Hey :blush: I have a few questions about the Agents.jl and collision implementation. I am using the Agents.jl library to model crowd dynamics in closed and geometrically constrained spaces. My first approach to this pro…

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## [How to plot a sequence of probability density functions as lines in (pseudo) 3D?](https://discourse.julialang.org/t/how-to-plot-a-sequence-of-probability-density-functions-as-lines-in-pseudo-3d/105614)

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**Author:** [@homocomputeris](https://discourse.julialang.org/u/homocomputeris)\
**Replies:** 7\
**Last updated:** [November 2, 2023, 11:42am UTC](https://discourse.julialang.org/t/how-to-plot-a-sequence-of-probability-density-functions-as-lines-in-pseudo-3d/105614 "2023-11-02T11:42:25Z")

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Given a set of PDFs f1(x), f2(x) etc., I’d like to plot something like this: The closest method I found is density from Makie, but it doesn’t work with functions or their values per se. How can I make such a plot?

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## [Converting a symbolic transfer function to a TransferFunction](https://discourse.julialang.org/t/converting-a-symbolic-transfer-function-to-a-transferfunction/103740)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 16\
**Last updated:** [November 2, 2023, 8:34am UTC](https://discourse.julialang.org/t/converting-a-symbolic-transfer-function-to-a-transferfunction/103740 "2023-11-02T08:34:36Z")

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Hello, any idea how to convert the following transfer function: julia\> res (-9.770075179266223e-8(s^4) - 2.543931256784638e-6(s^5) - 3.198336516372632e-5(s^6) - 0.00019354918819587642(s^7) - 0.000453357561824716(s^8)) …

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## [Makie series plot with only one label for legend?](https://discourse.julialang.org/t/makie-series-plot-with-only-one-label-for-legend/105403)

<div class="topic-metadata">

**Author:** [@matthew3245](https://discourse.julialang.org/u/matthew3245)\
**Replies:** 3\
**Last updated:** [November 2, 2023, 5:13am UTC](https://discourse.julialang.org/t/makie-series-plot-with-only-one-label-for-legend/105403 "2023-11-02T05:13:16Z")

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Does anyone know if its possible to make a series plot that includes only one label for the whole series (instead of an array of labels that get displayed on the legend). For example, say I had some experimental trial d…

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## [Transform several columns of an MLJ model using one transformer](https://discourse.julialang.org/t/transform-several-columns-of-an-mlj-model-using-one-transformer/105338)

<div class="topic-metadata">

**Author:** [@ParadaCarleton](https://discourse.julialang.org/u/ParadaCarleton)\
**Replies:** 13\
**Last updated:** [November 2, 2023, 1:02am UTC](https://discourse.julialang.org/t/transform-several-columns-of-an-mlj-model-using-one-transformer/105338 "2023-11-02T01:02:39Z")

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Is there an easy way to transform several columns of a table using the same MLJ transformer? So if I have a transformer like UnivariateBoxCoxTransformer, I’d like to apply it only to columns 2, 3, and 4. Alternatively, …

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