# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=339

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**Page:** 340

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## [Simple Regression using DiffEqFlux](https://discourse.julialang.org/t/simple-regression-using-diffeqflux/66842)

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**Author:** [@amit1](https://discourse.julialang.org/u/amit1)\
**Replies:** 6\
**Last updated:** [September 8, 2021, 6:27am UTC](https://discourse.julialang.org/t/simple-regression-using-diffeqflux/66842 "2021-09-08T06:27:53Z")

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I am trying to work out a simple application of NeuralODE for regression problems, based on the following tutorial. Core idea here being (as per my understanding) that regression problems can be modelled as y = \\int\_{…

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## [Conjugate gradient with incomplete Cholesky preconditioner](https://discourse.julialang.org/t/conjugate-gradient-with-incomplete-cholesky-preconditioner/7809)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 22\
**Last updated:** [September 6, 2021, 10:27pm UTC](https://discourse.julialang.org/t/conjugate-gradient-with-incomplete-cholesky-preconditioner/7809 "2021-09-06T22:27:13Z")

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I have been trying my luck with using the conjugate gradient method to solve a sparse symmetric positive definite system of equations. I found IterativeSolvers.jl, Krylov.jl and KrylovMethods.jl, of which the first seems…

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## [Annotations in Makie.jl](https://discourse.julialang.org/t/annotations-in-makie-jl/55773)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 4\
**Last updated:** [September 7, 2021, 8:50pm UTC](https://discourse.julialang.org/t/annotations-in-makie-jl/55773 "2021-09-07T20:50:50Z")

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Is it currently possible to annotate Makie-plots? I am thinking about having text at the root of an arrow that point to some location in the plot. I am imagining that one could DIY it by plotting a vector, and possible p…

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## [Permute x and y axes of a \`Makie.Axis\`](https://discourse.julialang.org/t/permute-x-and-y-axes-of-a-makie-axis/67826)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 2\
**Last updated:** [September 7, 2021, 8:21pm UTC](https://discourse.julialang.org/t/permute-x-and-y-axes-of-a-makie-axis/67826 "2021-09-07T20:21:21Z")

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This example shows how to reverse the direction of the x- and y-axis. However, I am interested in plotting the first coordinate of data along the vertical axis, and the second coordinate of data along the horizontal axis…

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## [Normal Inverse Gaussian distribution in Turing](https://discourse.julialang.org/t/normal-inverse-gaussian-distribution-in-turing/67831)

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**Author:** [@robertdj](https://discourse.julialang.org/u/robertdj)\
**Replies:** 0\
**Last updated:** [September 7, 2021, 8:00pm UTC](https://discourse.julialang.org/t/normal-inverse-gaussian-distribution-in-turing/67831 "2021-09-07T20:00:26Z")

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I’m trying to use Turing to do inference for a Normal-Inverse-Gaussian (NIG) distribution, but I have two problems: I can only make the inference work for certain realizations. The parameter restriction feels clumsy. M…

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## [Parametric surface plots with Makie](https://discourse.julialang.org/t/parametric-surface-plots-with-makie/67685)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 6\
**Last updated:** [September 7, 2021, 7:26pm UTC](https://discourse.julialang.org/t/parametric-surface-plots-with-makie/67685 "2021-09-07T19:26:11Z")

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I am a new user of Makie. How can I make a parametric plot of a surface in 3-dimensions with Makie? For example, I am looking for something like this: ParametricPlot3D—Wolfram Language Documentation Is there a similar…

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## [Huge jump in version numbers for coin-or binary dependencies](https://discourse.julialang.org/t/huge-jump-in-version-numbers-for-coin-or-binary-dependencies/67825)

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**Author:** [@ianfiske](https://discourse.julialang.org/u/ianfiske)\
**Replies:** 2\
**Last updated:** [September 7, 2021, 6:58pm UTC](https://discourse.julialang.org/t/huge-jump-in-version-numbers-for-coin-or-binary-dependencies/67825 "2021-09-07T18:58:42Z")

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After my most recent \] up, I saw \[38041ee0\] ↑ Cbc\_jll v2.10.3+5 ⇒ v200.1000.500+1 \[3830e938\] ↑ Cgl\_jll v0.60.2+6 ⇒ v0.6000.200+0 \[06985876\] ↑ Clp\_jll v1.17.6+7 ⇒ v100.1700.600+0 Did something go wrong in the buil…

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## [DataFrame select, un-nesting a column containing tuples into three columns](https://discourse.julialang.org/t/dataframe-select-un-nesting-a-column-containing-tuples-into-three-columns/67726)

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**Author:** [@marcello](https://discourse.julialang.org/u/marcello)\
**Replies:** 2\
**Last updated:** [September 7, 2021, 6:02pm UTC](https://discourse.julialang.org/t/dataframe-select-un-nesting-a-column-containing-tuples-into-three-columns/67726 "2021-09-07T18:02:46Z")

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Hello, I’ve been following the JuliaCon 2021 tutorial on DataFrames https://github.com/bkamins/JuliaCon2021-DataFrames-Tutorial I’m using Julia 1.6.2 on VSCodium after exporting the Tutorial.ipynb into tutorial.js Th…

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## [Statistics in Julia good enough for my course?](https://discourse.julialang.org/t/statistics-in-julia-good-enough-for-my-course/67409)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 15\
**Last updated:** [September 7, 2021, 2:51pm UTC](https://discourse.julialang.org/t/statistics-in-julia-good-enough-for-my-course/67409 "2021-09-07T14:51:30Z")

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I am starting a Statistics course tomorrow, as an undergrad. While prepping for class, I met the following statement: The faculty I am in at my school swears to MatLab for most things, and I have followed courses on …

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## [ChainRulesCore: Custom adjoint ignored in certain cases](https://discourse.julialang.org/t/chainrulescore-custom-adjoint-ignored-in-certain-cases/67814)

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**Author:** [@Rasmus\_Hoier](https://discourse.julialang.org/u/Rasmus_Hoier)\
**Replies:** 3\
**Last updated:** [September 7, 2021, 2:32pm UTC](https://discourse.julialang.org/t/chainrulescore-custom-adjoint-ignored-in-certain-cases/67814 "2021-09-07T14:32:10Z")

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Hi, A colleague of mine ran into the issue that custom adjoints get ignored in certain cases in recent versions of ChainRulesCore. Here is a minimal working example: using Flux, ChainRulesCore my\_fun(x) = x\*x …

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## [Convexifying a 6-dimensional closed trajectory with \`LazySets.jl\`](https://discourse.julialang.org/t/convexifying-a-6-dimensional-closed-trajectory-with-lazysets-jl/67764)

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**Author:** [@cadojo](https://discourse.julialang.org/u/cadojo)\
**Replies:** 2\
**Last updated:** [September 7, 2021, 11:01am UTC](https://discourse.julialang.org/t/convexifying-a-6-dimensional-closed-trajectory-with-lazysets-jl/67764 "2021-09-07T11:01:35Z")

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First off, if anyone knows how to change the tag reachability-analysi to reachability-analysis, please do so! Discourse won’t let me type reachability-analysis in the category because a previous tag with an incorrect spe…

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## [Eigen not working for arbitrary precision BigFloat](https://discourse.julialang.org/t/eigen-not-working-for-arbitrary-precision-bigfloat/67686)

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**Author:** [@ekiral](https://discourse.julialang.org/u/ekiral)\
**Replies:** 16\
**Last updated:** [September 7, 2021, 11:11am UTC](https://discourse.julialang.org/t/eigen-not-working-for-arbitrary-precision-bigfloat/67686 "2021-09-07T11:11:51Z")

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I try to use the function eigen defined on a matrix with BigFloat entries. The method does not work. julia\> matrix = \[BigFloat(2) BigFloat(3); BigFloat(3), BigFloat(2)\] julia\> matrix 2x2 Matrix{BigFloat}: 2.0 3.0 …

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## [System data in different formats in PowerModels.jl](https://discourse.julialang.org/t/system-data-in-different-formats-in-powermodels-jl/67344)

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**Author:** [@Mariana](https://discourse.julialang.org/u/Mariana)\
**Replies:** 2\
**Last updated:** [September 7, 2021, 9:14am UTC](https://discourse.julialang.org/t/system-data-in-different-formats-in-powermodels-jl/67344 "2021-09-07T09:14:56Z")

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Hello. I’m using PowerModels.jl to study different power flow methods. However, for a specific system that I’m studying, I don’t have all the data in a single file. Also, the system’s data files I have are in different …

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## [How to "label" DataFrame categorical column?](https://discourse.julialang.org/t/how-to-label-dataframe-categorical-column/67790)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [September 7, 2021, 7:35am UTC](https://discourse.julialang.org/t/how-to-label-dataframe-categorical-column/67790 "2021-09-07T07:35:01Z")

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How can I rename the levels of a categorical column in a DataFrame? I tried this but it throws an error: using DataFrames using CategoricalArrays df = DataFrame(x=\[1, 2, 3\]) df.x = categorical(df.x) levels!(df.x, \["one…

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## [Two questions about GLM](https://discourse.julialang.org/t/two-questions-about-glm/10376)

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**Author:** [@mwsohn](https://discourse.julialang.org/u/mwsohn)\
**Replies:** 4\
**Last updated:** [September 7, 2021, 5:55am UTC](https://discourse.julialang.org/t/two-questions-about-glm/10376 "2021-09-07T05:55:59Z")

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I have noticed that I could not use a CategoricalArray as the dependent variable for a logistic regression. When I convert the binary dependent variable into a Float64, then I can estimate the model without any problem. …

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## [Setting parameters for \`ReachabilityAnalysis\`'s \`@ivp\`](https://discourse.julialang.org/t/setting-parameters-for-reachabilityanalysis-s-ivp/67776)

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**Author:** [@cadojo](https://discourse.julialang.org/u/cadojo)\
**Replies:** 1\
**Last updated:** [September 7, 2021, 12:53am UTC](https://discourse.julialang.org/t/setting-parameters-for-reachabilityanalysis-s-ivp/67776 "2021-09-07T00:53:54Z")

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I see in documentation for ReachabilityAnalysis that parameters are typically set in a function, as is the case in the duffing oscillator example. I’m working with a system where the ODEFunction was automatically generat…

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## [Simulating evolutionary birth-death processes with EvoId.jl](https://discourse.julialang.org/t/simulating-evolutionary-birth-death-processes-with-evoid-jl/65867)

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**Author:** [@boutor2](https://discourse.julialang.org/u/boutor2)\
**Replies:** 1\
**Last updated:** [September 6, 2021, 7:47pm UTC](https://discourse.julialang.org/t/simulating-evolutionary-birth-death-processes-with-evoid-jl/65867 "2021-09-06T19:47:05Z")

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Hello guys, I am posting here a link to EvoId.jl, a package that I have been developing for my research. EvoId.jl is purposed for numerical experiments in theoretical evolutionary biology, and implements a few algorithm…

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## [Trying to understand 3d indexing](https://discourse.julialang.org/t/trying-to-understand-3d-indexing/67525)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 3\
**Last updated:** [September 6, 2021, 9:51am UTC](https://discourse.julialang.org/t/trying-to-understand-3d-indexing/67525 "2021-09-06T09:51:53Z")

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I prepared kernel with thread dimensions 4, 4,1 and iterating over array of dimensionality 16,16,2 and 32 blocks as far as my calculations all should work - all divides without remainder but I get constantly ERROR: Ou…

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## [Laplace equation in one dimension](https://discourse.julialang.org/t/laplace-equation-in-one-dimension/67715)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 5\
**Last updated:** [September 6, 2021, 2:25am UTC](https://discourse.julialang.org/t/laplace-equation-in-one-dimension/67715 "2021-09-06T02:25:55Z")

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Please solve the Laplace equation in one dimension on a region bounded between x ∈ \[0, 1\], with the boundary condition Φ(0) = 1, and Φ(1) = 2. Actually line should pass through (0,1) making 45 degree with x,y-axis.

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## [Getting strange "UndefVarError: xs not defined" in Zygote / Flux](https://discourse.julialang.org/t/getting-strange-undefvarerror-xs-not-defined-in-zygote-flux/67707)

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**Author:** [@outlace](https://discourse.julialang.org/u/outlace)\
**Replies:** 3\
**Last updated:** [September 5, 2021, 10:18pm UTC](https://discourse.julialang.org/t/getting-strange-undefvarerror-xs-not-defined-in-zygote-flux/67707 "2021-09-05T22:18:41Z")

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I’ve got a fairly simple custom 2-layer MLP implementation but I get this strange error when trying to get the gradient: LoadError: UndefVarError: xs not defined UndefVarError: xs not defined Here’s my full code using…

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## [Subsetting boolean columns and multiple assignments](https://discourse.julialang.org/t/subsetting-boolean-columns-and-multiple-assignments/67716)

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**Author:** [@jacobusmmsmit](https://discourse.julialang.org/u/jacobusmmsmit)\
**Replies:** 5\
**Last updated:** [September 5, 2021, 8:37pm UTC](https://discourse.julialang.org/t/subsetting-boolean-columns-and-multiple-assignments/67716 "2021-09-05T20:37:54Z")

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Hello, I have two related questions both related to the following code: df = DataFrame(a = \[true, true, false\]) subset1 = subset(df, :a) subset2 = subset(df, :a =\> ByRow(!=(true))) I want to be able to do something lik…

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## [Makie animation: type FigureAxisPlot has no field plots](https://discourse.julialang.org/t/makie-animation-type-figureaxisplot-has-no-field-plots/67696)

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**Author:** [@GoH](https://discourse.julialang.org/u/GoH)\
**Replies:** 2\
**Last updated:** [September 5, 2021, 8:35am UTC](https://discourse.julialang.org/t/makie-animation-type-figureaxisplot-has-no-field-plots/67696 "2021-09-05T08:35:38Z")

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Hi i am trying to run the example code in http://juliaplots.org/MakieGallery.jl/stable/animation.html, but got an error of type FigureAxisPlot has no field plots getproperty(::Makie.FigureAxisPlot, ::Symbol)@Base.jl:33…

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## [Will Flux/Zygote compute gradients sparsely?](https://discourse.julialang.org/t/will-flux-zygote-compute-gradients-sparsely/67542)

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**Author:** [@outlace](https://discourse.julialang.org/u/outlace)\
**Replies:** 7\
**Last updated:** [September 4, 2021, 10:30pm UTC](https://discourse.julialang.org/t/will-flux-zygote-compute-gradients-sparsely/67542 "2021-09-04T22:30:03Z")

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So in short I want to train an MLP by sparsely updating it’s parameters. I do this on the forward pass by randomly subsampling the columns of my parameter matrices. E.g. for a simple 2 layer model on MINST with input dat…

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## [Examples of analysis that can be done with SatelliteToolbox.jl](https://discourse.julialang.org/t/examples-of-analysis-that-can-be-done-with-satellitetoolbox-jl/19330)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 28\
**Last updated:** [September 4, 2021, 8:34pm UTC](https://discourse.julialang.org/t/examples-of-analysis-that-can-be-done-with-satellitetoolbox-jl/19330 "2021-09-04T20:34:58Z")

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Hi guys! Just to let you know that I added to my blog a introductory post about the SatelliteToolbox.jl package: https://ronanarraes.com/tutorials/julia/the-satellitetoolbox-for-julia/ I also provided two examples of a…

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## [Specify the admissible region of SIS model when plotting its phase portrait, using streamplot](https://discourse.julialang.org/t/specify-the-admissible-region-of-sis-model-when-plotting-its-phase-portrait-using-streamplot/67688)

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**Author:** [@GoH](https://discourse.julialang.org/u/GoH)\
**Replies:** 4\
**Last updated:** [September 4, 2021, 2:43pm UTC](https://discourse.julialang.org/t/specify-the-admissible-region-of-sis-model-when-plotting-its-phase-portrait-using-streamplot/67688 "2021-09-04T14:43:05Z")

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Hi I am trying to visualize the phase space of SIS model, but here is what I obtained. The problem is the trajectories should on the line of S+I=1, but somehow they did not, in the plot. here is my code begin using…

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## [What is the difference btween handling f\[i,j\]=GridLayout() and g=f\[i,j\]=GridLayout()](https://discourse.julialang.org/t/what-is-the-difference-btween-handling-f-i-j-gridlayout-and-g-f-i-j-gridlayout/67675)

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**Author:** [@thudjx](https://discourse.julialang.org/u/thudjx)\
**Replies:** 7\
**Last updated:** [September 4, 2021, 1:37pm UTC](https://discourse.julialang.org/t/what-is-the-difference-btween-handling-f-i-j-gridlayout-and-g-f-i-j-gridlayout/67675 "2021-09-04T13:37:46Z")

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I am trying to plot a 2x2 figure as shown below. So I import CairoMakie for ir in 1:2, ic in 1:2 g = f\[ir,ic\] = GridLayout() # handling g below end But if I try the following code: for ir in 1:2, ic in 1:…

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## [Transparent plotting in Makie](https://discourse.julialang.org/t/transparent-plotting-in-makie/67625)

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**Author:** [@yosuga](https://discourse.julialang.org/u/yosuga)\
**Replies:** 9\
**Last updated:** [September 4, 2021, 9:42am UTC](https://discourse.julialang.org/t/transparent-plotting-in-makie/67625 "2021-09-04T09:42:12Z")

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BeautifulMakie is very helpful for 3D plotting. But, in this volume with scatters, x,y,z, f(x,y,z) example, I can’t see inside the box e.g. the values at (x,y,z)=(5,5,5) or (0,0,0). I want something like this example,“D…

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## [Best way to define a set of differential equations?](https://discourse.julialang.org/t/best-way-to-define-a-set-of-differential-equations/67650)

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**Author:** [@pafloxy](https://discourse.julialang.org/u/pafloxy)\
**Replies:** 6\
**Last updated:** [September 4, 2021, 9:11am UTC](https://discourse.julialang.org/t/best-way-to-define-a-set-of-differential-equations/67650 "2021-09-04T09:11:06Z")

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Hi! I am using DifferentialEquations.jl for simulating trajectories over high-dimensional vector fields. For my case, the time-evolution function for each coordinate is generated by a pre-defined random function (\*\* sa…

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## [Why don't remotecalls to a WorkerPool block when all workers are busy?](https://discourse.julialang.org/t/why-dont-remotecalls-to-a-workerpool-block-when-all-workers-are-busy/22059)

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**Author:** [@Cody-G](https://discourse.julialang.org/u/Cody-G)\
**Replies:** 6\
**Last updated:** [September 3, 2021, 7:09pm UTC](https://discourse.julialang.org/t/why-dont-remotecalls-to-a-workerpool-block-when-all-workers-are-busy/22059 "2021-09-03T19:09:20Z")

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Based on the docs for remotecall I expect the WorkerPool variant to block until a worker in the pool is available for a new job. From docs: remotecall(f, pool::AbstractWorkerPool, args...; kwargs...) -\> Future Work…

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## [How to exchange x-y axis and layout with another image?](https://discourse.julialang.org/t/how-to-exchange-x-y-axis-and-layout-with-another-image/67615)

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**Author:** [@thudjx](https://discourse.julialang.org/u/thudjx)\
**Replies:** 3\
**Last updated:** [September 3, 2021, 5:52pm UTC](https://discourse.julialang.org/t/how-to-exchange-x-y-axis-and-layout-with-another-image/67615 "2021-09-03T17:52:46Z")

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All I want to achieve is something like this: the second plot should be drawn with x-y axes exchanged y axis of the two plots should be overlayed Can anyone help me about this? Thanks in advance.

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