# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=218

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**Page:** 219

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## [LoadError: @atomic modify expression missing field access](https://discourse.julialang.org/t/loaderror-atomic-modify-expression-missing-field-access/93973)

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**Author:** [@bcsj](https://discourse.julialang.org/u/bcsj)\
**Replies:** 1\
**Last updated:** [February 3, 2023, 8:18am UTC](https://discourse.julialang.org/t/loaderror-atomic-modify-expression-missing-field-access/93973 "2023-02-03T08:18:35Z")

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I’ve been trying to write a reduction kernel using \[1\] as a blueprint to work from, but I kept getting this error message: LoadError: @atomic modify expression missing field access I couldn’t understand why, and in t…

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## [Automatic gradient ∼10x slower to evaluate than the primal computation](https://discourse.julialang.org/t/automatic-gradient-10x-slower-to-evaluate-than-the-primal-computation/93925)

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**Author:** [@user22](https://discourse.julialang.org/u/user22)\
**Replies:** 2\
**Last updated:** [February 3, 2023, 6:15am UTC](https://discourse.julialang.org/t/automatic-gradient-10x-slower-to-evaluate-than-the-primal-computation/93925 "2023-02-03T06:15:44Z")

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I need to evaluate a basic dense and a few-layer neural network with up to tens of thousands of inputs at once. The outputs will be then forwarded to another function, which returns a scalar. However, the performance of …

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## [JuMP MethodError: Cannot \`convert\` an object of type AffExpr to an object of type VariableRef](https://discourse.julialang.org/t/jump-methoderror-cannot-convert-an-object-of-type-affexpr-to-an-object-of-type-variableref/93951)

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**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 2\
**Last updated:** [February 3, 2023, 1:35am UTC](https://discourse.julialang.org/t/jump-methoderror-cannot-convert-an-object-of-type-affexpr-to-an-object-of-type-variableref/93951 "2023-02-03T01:35:18Z")

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The first way of imposing the constraints works. The second way causes the error below. Is there a better way to impose theses constraints? using JuMP using LinearAlgebra v = 64 J = 10 model = Model() @variable(model, …

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## [Generating derived variables from ModelingToolkit.jl - variable of interest eliminated during structural\_simplify](https://discourse.julialang.org/t/generating-derived-variables-from-modelingtoolkit-jl-variable-of-interest-eliminated-during-structural-simplify/93939)

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**Author:** [@sdwfrost](https://discourse.julialang.org/u/sdwfrost)\
**Replies:** 8\
**Last updated:** [February 2, 2023, 10:56pm UTC](https://discourse.julialang.org/t/generating-derived-variables-from-modelingtoolkit-jl-variable-of-interest-eliminated-during-structural-simplify/93939 "2023-02-02T22:56:04Z")

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Hi everyone, I’m trying to generate variables that are functions of my state variables in an ODE. Here’s my example. using ModelingToolkit using OrdinaryDiffEq @parameters t β c γ @variables S(t) I(t) R(t) λ(t) D = Di…

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## [Solution of 3d linear system](https://discourse.julialang.org/t/solution-of-3d-linear-system/93931)

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**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 15\
**Last updated:** [February 2, 2023, 8:52pm UTC](https://discourse.julialang.org/t/solution-of-3d-linear-system/93931 "2023-02-02T20:52:49Z")

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Hello, good morning. Im trying to solve this 3d system, that will plot a plane in surface. I have a matlab book and I’m porting some exercises. The solution is a line between the two planes as the book shows: In m…

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## [Solving systems of partial differential equations](https://discourse.julialang.org/t/solving-systems-of-partial-differential-equations/93947)

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**Author:** [@bombadil224](https://discourse.julialang.org/u/bombadil224)\
**Replies:** 0\
**Last updated:** [February 2, 2023, 7:18pm UTC](https://discourse.julialang.org/t/solving-systems-of-partial-differential-equations/93947 "2023-02-02T19:18:35Z")

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I have been trying to find a way for a while now to simulate a few different systems of PDEs. What I need to be able to do is change both the initial conditions and the system of equations, without having to go through a…

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## [What is wrong with this system of ODEs?](https://discourse.julialang.org/t/what-is-wrong-with-this-system-of-odes/93924)

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**Author:** [@Ali\_Vahdati](https://discourse.julialang.org/u/Ali_Vahdati)\
**Replies:** 2\
**Last updated:** [February 2, 2023, 7:12pm UTC](https://discourse.julialang.org/t/what-is-wrong-with-this-system-of-odes/93924 "2023-02-02T19:12:14Z")

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I have a system with 5 linear ODEs. The code runs and the results are just what I expect. In a second system, I expand the first system by duplicating the five equations. There are now 10 equations where there is no conn…

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## [Interactive Menu with AlgebraOfGraphics / GLMakie](https://discourse.julialang.org/t/interactive-menu-with-algebraofgraphics-glmakie/93842)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 15\
**Last updated:** [February 2, 2023, 5:53pm UTC](https://discourse.julialang.org/t/interactive-menu-with-algebraofgraphics-glmakie/93842 "2023-02-02T17:53:46Z")

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Hello, I am trying to have an interactive AlgebraofGraphics plot, e.g. with a menu to select which variable is plotted. A MWE is x1=rand(50) y1=10x1.^2 y2=x1 .+ randn(50) df = DataFrame((;x1, y1, y2)) var=Observable(…

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## [Elegant way to handle multiple input flux layers?](https://discourse.julialang.org/t/elegant-way-to-handle-multiple-input-flux-layers/93913)

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**Author:** [@reachtarunhere](https://discourse.julialang.org/u/reachtarunhere)\
**Replies:** 4\
**Last updated:** [February 2, 2023, 5:50pm UTC](https://discourse.julialang.org/t/elegant-way-to-handle-multiple-input-flux-layers/93913 "2023-02-02T17:50:47Z")

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The issue I am pointing at arrives when implementing encoder for transformer models with masking. Below I have tried to do a fake minimal example instead. We have a custom layer which takes a couple of inputs. For a tra…

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## [Why the Loss function does not decrease significantly in Flux.jl](https://discourse.julialang.org/t/why-the-loss-function-does-not-decrease-significantly-in-flux-jl/93918)

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**Author:** [@quantiota](https://discourse.julialang.org/u/quantiota)\
**Replies:** 2\
**Last updated:** [February 2, 2023, 4:50pm UTC](https://discourse.julialang.org/t/why-the-loss-function-does-not-decrease-significantly-in-flux-jl/93918 "2023-02-02T16:50:00Z")

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After trying some optimizations on activation function and epochs value , it is not possible to fit the model to y data which is a function of the input data. using Flux, Plots, Statistics x = Array{Float64}(rand(5, 100…

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## [Distribution of sum of random variables](https://discourse.julialang.org/t/distribution-of-sum-of-random-variables/69023)

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**Author:** [@alexdmeyer](https://discourse.julialang.org/u/alexdmeyer)\
**Replies:** 18\
**Last updated:** [February 2, 2023, 3:06pm UTC](https://discourse.julialang.org/t/distribution-of-sum-of-random-variables/69023 "2023-02-02T15:06:35Z")

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Hey Julia folks, An equation I came across in my research requires evaluating the distribution of a linear combination of two random variables, aX + bY. Does the Distributions.jl package have a nice way to do this? More…

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## [How could I create map with colored countries?](https://discourse.julialang.org/t/how-could-i-create-map-with-colored-countries/75634)

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**Author:** [@maajdl](https://discourse.julialang.org/u/maajdl)\
**Replies:** 5\
**Last updated:** [February 2, 2023, 3:01pm UTC](https://discourse.julialang.org/t/how-could-i-create-map-with-colored-countries/75634 "2023-02-02T15:01:04Z")

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Hello Below is the kind of maps I would like to draw. The colors would be changing according to some data. I would dream of making animated gif files on this basis. Any idea how I coul proceed? Thanks Michel

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## [Visualizing and understanding Fourier transforms](https://discourse.julialang.org/t/visualizing-and-understanding-fourier-transforms/93898)

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**Author:** [@skittishdev](https://discourse.julialang.org/u/skittishdev)\
**Replies:** 4\
**Last updated:** [February 2, 2023, 2:07pm UTC](https://discourse.julialang.org/t/visualizing-and-understanding-fourier-transforms/93898 "2023-02-02T14:07:38Z")

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Hi, I am trying to understand Fourier transforms, and decided to create some plots using Julia to help validate my own understanding. What I want Create a known signal as a sum/product of 2 other simple sinusoidal si…

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## [How to improve the calculation speed of this kernel on GPU?](https://discourse.julialang.org/t/how-to-improve-the-calculation-speed-of-this-kernel-on-gpu/93831)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 2\
**Last updated:** [February 2, 2023, 1:10pm UTC](https://discourse.julialang.org/t/how-to-improve-the-calculation-speed-of-this-kernel-on-gpu/93831 "2023-02-02T13:10:26Z")

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Hello everyone! I have worked quite a bit on setting up a robust foundation for structuring my code and computation loop, with quite a few good pointers from you guys on the forum, so I hope to be able to learn more fro…

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## [AdaptiveMCMC defining prior and multivariate parameters](https://discourse.julialang.org/t/adaptivemcmc-defining-prior-and-multivariate-parameters/93917)

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**Author:** [@astro-kevin](https://discourse.julialang.org/u/astro-kevin)\
**Replies:** 0\
**Last updated:** [February 2, 2023, 11:46am UTC](https://discourse.julialang.org/t/adaptivemcmc-defining-prior-and-multivariate-parameters/93917 "2023-02-02T11:46:11Z")

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I’m trying to make a start on making a MCMC chain using AdaptiveMCMC. I’ve figured out a function which returns a log-likelihood given a specific set of parameters (a vector of parameters). I’m not quite sure how this go…

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## [Integrating MLUtils.DataLoader and image augmentation pipeline on custom dataset](https://discourse.julialang.org/t/integrating-mlutils-dataloader-and-image-augmentation-pipeline-on-custom-dataset/93887)

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**Author:** [@rkube](https://discourse.julialang.org/u/rkube)\
**Replies:** 5\
**Last updated:** [February 2, 2023, 7:05am UTC](https://discourse.julialang.org/t/integrating-mlutils-dataloader-and-image-augmentation-pipeline-on-custom-dataset/93887 "2023-02-02T07:05:08Z")

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Hi, I’m trying to create a custom dataset where getobs performs random image augmentations. The DataLoader docs suggest that my dataset has to have custom numobs and getobs calls. So this is my code: struct my\_datase…

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## [Defining a JuMP binary variable](https://discourse.julialang.org/t/defining-a-jump-binary-variable/93904)

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**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 1\
**Last updated:** [February 2, 2023, 4:44am UTC](https://discourse.julialang.org/t/defining-a-jump-binary-variable/93904 "2023-02-02T04:44:44Z")

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Is there a difference in performance within JuMP, MOI, and/or the third-party MILP solver between the two possible ways of defining a binary variable given below? @variable(m, b, Int, lower\_bound = 0, upper\_bound = 1) …

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## [Makie | Figure(resolution = Makie.primary\_resolution()) deprecated?](https://discourse.julialang.org/t/makie-figure-resolution-makie-primary-resolution-deprecated/93854)

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**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 4\
**Last updated:** [February 2, 2023, 4:44am UTC](https://discourse.julialang.org/t/makie-figure-resolution-makie-primary-resolution-deprecated/93854 "2023-02-02T04:44:41Z")

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Makie.primary\_resolution() is \[was?\] a useful function for setting images to full screen size in GLMakie. However, after the release of Makie v0.19.2 a call to this function generates an error message stating that the…

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## [Can not run simple example with LIBSVM](https://discourse.julialang.org/t/can-not-run-simple-example-with-libsvm/93875)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 4\
**Last updated:** [February 1, 2023, 7:24pm UTC](https://discourse.julialang.org/t/can-not-run-simple-example-with-libsvm/93875 "2023-02-01T19:24:53Z")

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I am trying to run this code: using LIBSVM x = randn(20, 2) labels = repeat(\[-1,1\], 10) model = svmtrain(x', labels) I tried to run it in JupyterLab, VSCode and REPL but it gives me a definitive error (the kernel di…

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## [Batched Matrix solve in CUDA.jl](https://discourse.julialang.org/t/batched-matrix-solve-in-cuda-jl/52855)

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**Author:** [@jpdoane](https://discourse.julialang.org/u/jpdoane)\
**Replies:** 3\
**Last updated:** [February 1, 2023, 7:00pm UTC](https://discourse.julialang.org/t/batched-matrix-solve-in-cuda-jl/52855 "2023-02-01T19:00:38Z")

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Is there a way to perform batched matrix inversion/ldiv in CUDA.jl, ie: Yi = Ri \\ Xi where Ri is NxN, and Yi and Xi are NxM, with N and M small (~12). I need to solve a large number of these systems, e.g. 1 \< i \< 50k.…

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## [The VS Code plot navigator and Makie](https://discourse.julialang.org/t/the-vs-code-plot-navigator-and-makie/67967)

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**Author:** [@garrek](https://discourse.julialang.org/u/garrek)\
**Replies:** 13\
**Last updated:** [February 1, 2023, 7:00pm UTC](https://discourse.julialang.org/t/the-vs-code-plot-navigator-and-makie/67967 "2023-02-01T19:00:08Z")

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I want to clarify something that confused me when using CairoMakie and GLMakie in Visual Studio Code. I couldn’t find an explanation in the Makie documentation, so I’ll make a topic here to help anyone else who runs into…

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## [Set-like operations on DataFrames?](https://discourse.julialang.org/t/set-like-operations-on-dataframes/32004)

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**Author:** [@innerlee](https://discourse.julialang.org/u/innerlee)\
**Replies:** 13\
**Last updated:** [February 1, 2023, 12:08pm UTC](https://discourse.julialang.org/t/set-like-operations-on-dataframes/32004 "2023-02-01T12:08:32Z")

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How to merge two dataframes with the same columns, similar to set operations? For example, whether there are functions like df = union(df1, df2, on=:ID) df = intersect(df1, df2, on=:ID) df = diff(df1, df2, on=:ID)

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## [How to add sleep to "JuliaRL\_BasicDQN\_CartPole"?](https://discourse.julialang.org/t/how-to-add-sleep-to-juliarl-basicdqn-cartpole/93810)

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**Author:** [@MikeB](https://discourse.julialang.org/u/MikeB)\
**Replies:** 7\
**Last updated:** [February 1, 2023, 9:08am UTC](https://discourse.julialang.org/t/how-to-add-sleep-to-juliarl-basicdqn-cartpole/93810 "2023-02-01T09:08:17Z")

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I’m trying to use the above-named ReinforcementLearning.jl experiment to model training a DQN that calls out to another program and introduces some lag time. I can, of course, run the experiment but I can’t quite figure …

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## [Changing RL Experiment Arguments](https://discourse.julialang.org/t/changing-rl-experiment-arguments/93856)

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**Author:** [@MikeB](https://discourse.julialang.org/u/MikeB)\
**Replies:** 1\
**Last updated:** [February 1, 2023, 9:06am UTC](https://discourse.julialang.org/t/changing-rl-experiment-arguments/93856 "2023-02-01T09:06:52Z")

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This is kind of embarrassing, but, I can’t figure out how to change the seed=123 argument on the DQN\_Cartpole experiment. I threw the code into a Jupyter notebook, with the function in one big cell, then the ex=E'JuliaR…

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## [Help in Optim/optimize - structure of code and help](https://discourse.julialang.org/t/help-in-optim-optimize-structure-of-code-and-help/93656)

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**Author:** [@Outeirom](https://discourse.julialang.org/u/Outeirom)\
**Replies:** 2\
**Last updated:** [February 1, 2023, 3:55am UTC](https://discourse.julialang.org/t/help-in-optim-optimize-structure-of-code-and-help/93656 "2023-02-01T03:55:49Z")

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I have a code taht is more or less like this: fixed parameters \\alpha, \\beta... that never changes #then I have vector of parameters I want to calibrate (theta) and target (mom\_data) theta = \[ \*vector of parameters to …

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## [Disable warnings in \`Plots\`](https://discourse.julialang.org/t/disable-warnings-in-plots/93838)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 3\
**Last updated:** [January 31, 2023, 11:34pm UTC](https://discourse.julialang.org/t/disable-warnings-in-plots/93838 "2023-01-31T23:34:50Z")

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I am using Plots to plot(data,options...). This produces tons of Warnings like: ┌ Warning: Indices Base.OneTo(7) of attribute \`fillcolor\` does not match data indices 1:6. └ @ Plots ~/.julia/packages/Plots/AAjgN/src/util…

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## [Update xlims in interactive GLMakie](https://discourse.julialang.org/t/update-xlims-in-interactive-glmakie/93825)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 5\
**Last updated:** [January 31, 2023, 10:49pm UTC](https://discourse.julialang.org/t/update-xlims-in-interactive-glmakie/93825 "2023-01-31T22:49:51Z")

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I have the question how to make xlims and ylims update automatically when an Observable changes. For instance: x=1:10 |\> collect |\> Observable fig, ax, plt = scatter(x, @lift($x .^ 2)) fig Updating x does not lead to …

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## [How to get ordering of constraints when calling eval\_constraint?](https://discourse.julialang.org/t/how-to-get-ordering-of-constraints-when-calling-eval-constraint/93772)

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**Author:** [@hugh\_man](https://discourse.julialang.org/u/hugh_man)\
**Replies:** 2\
**Last updated:** [January 31, 2023, 4:00pm UTC](https://discourse.julialang.org/t/how-to-get-ordering-of-constraints-when-calling-eval-constraint/93772 "2023-01-31T16:00:09Z")

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Hello, I have a large JuMP model constructed programmatically as a function of some input data. My ultimate goal is to plug in arbitrary values into the variables and evaluate the values of the constraints. To accompi…

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## [Can I integrate 2 functions simultaneously in DifferentialEquations.jl?](https://discourse.julialang.org/t/can-i-integrate-2-functions-simultaneously-in-differentialequations-jl/93801)

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**Author:** [@shaurya](https://discourse.julialang.org/u/shaurya)\
**Replies:** 3\
**Last updated:** [January 31, 2023, 3:53pm UTC](https://discourse.julialang.org/t/can-i-integrate-2-functions-simultaneously-in-differentialequations-jl/93801 "2023-01-31T15:53:21Z")

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I have 2 coupled systems of differential equations, used for spacecraft simulation, which are to be integrated simultaneously: In this system, omega\_i and epsilon\_j are the variables. (i belongs to {1,2,3} and j be…

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## [Logscale on negative real axis](https://discourse.julialang.org/t/logscale-on-negative-real-axis/93814)

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**Author:** [@gvdeynde](https://discourse.julialang.org/u/gvdeynde)\
**Replies:** 6\
**Last updated:** [January 31, 2023, 11:41am UTC](https://discourse.julialang.org/t/logscale-on-negative-real-axis/93814 "2023-01-31T11:41:12Z")

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Hi all I have a function, foo(x), which is defined only on the negative real axis. The range is quite wide and I want to plot it in log-scale, say from x=-1.0e7 to x=-1.0e-7. How can I “transform” the axis in Makie to a…

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