# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1142

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1143

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## [Help optimizing bad multithreading code](https://discourse.julialang.org/t/help-optimizing-bad-multithreading-code/75099)

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**Author:** [@isaac.rubberducky](https://discourse.julialang.org/u/isaac.rubberducky)\
**Replies:** 2\
**Last updated:** [January 25, 2022, 2:41pm UTC](https://discourse.julialang.org/t/help-optimizing-bad-multithreading-code/75099 "2022-01-25T14:41:00Z")

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function cleanExample(rootNode::Node) queue = Vector{Node}() push!(queue, rootNode) bestKnownSolution = 100 queueLock = ReentrantLock() solutionLock = ReentrantLock() while !isempty(queue) …

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## [Help with setting up Distributed computing](https://discourse.julialang.org/t/help-with-setting-up-distributed-computing/75081)

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**Author:** [@isaac.rubberducky](https://discourse.julialang.org/u/isaac.rubberducky)\
**Replies:** 5\
**Last updated:** [January 25, 2022, 2:39pm UTC](https://discourse.julialang.org/t/help-with-setting-up-distributed-computing/75081 "2022-01-25T14:39:04Z")

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queue = Vector{Node}() push!(queue, rootNode) bestKnownSolution = 100 while !isempty(queue) nextNode = pop!(queue) newNode1, newNode2, bestFoundSolution = processNode!(nextNode) if !isnothing(newNode1) …

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## [Domain error in circuit DAE](https://discourse.julialang.org/t/domain-error-in-circuit-dae/73542)

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**Author:** [@dfcaporale](https://discourse.julialang.org/u/dfcaporale)\
**Replies:** 7\
**Last updated:** [January 25, 2022, 2:11pm UTC](https://discourse.julialang.org/t/domain-error-in-circuit-dae/73542 "2022-01-25T14:11:53Z")

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I’m trying to solve the following DAE: \\begin{cases} i\_R=C \\displaystyle \\frac{dV\_o}{dt} \\\\ i\_R= \\displaystyle \\frac{V\_{in}(t)-V\_o-nV\_T \\ln \\displaystyle (1+\\displaystyle \\frac{i\_R}{I\_s}) }{R} \\end{cas…

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## [A way to capture screenshots with Julia programatically](https://discourse.julialang.org/t/a-way-to-capture-screenshots-with-julia-programatically/57666)

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**Author:** [@sefffal](https://discourse.julialang.org/u/sefffal)\
**Replies:** 8\
**Last updated:** [January 25, 2022, 1:44pm UTC](https://discourse.julialang.org/t/a-way-to-capture-screenshots-with-julia-programatically/57666 "2022-01-25T13:44:30Z")

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Today I found a simple way to capture a screenshot of your desktop using Julia and thought I would share. I guess it is a hidden feature of the ImageMagick.jl package. Just run using ImageMagick screenshot = ImageMagi…

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## [\[ANN\] FdeSolver.jl: solve fractional differential equations (FDEs)](https://discourse.julialang.org/t/ann-fdesolver-jl-solve-fractional-differential-equations-fdes/71371)

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**Author:** [@Giulio\_Benedetti](https://discourse.julialang.org/u/Giulio_Benedetti)\
**Replies:** 5\
**Last updated:** [January 25, 2022, 12:48pm UTC](https://discourse.julialang.org/t/ann-fdesolver-jl-solve-fractional-differential-equations-fdes/71371 "2022-01-25T12:48:26Z")

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I’d like to announce a package for solving differential equations (and systems) with fractional derivatives (in the sense of Caputo). Fractional derivatives are suitable tools for modeling memory effects in complex syst…

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## [Announcing Neptune.jl (now updated to multi-line cells!)](https://discourse.julialang.org/t/announcing-neptune-jl-now-updated-to-multi-line-cells/54088)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 97\
**Last updated:** [January 25, 2022, 12:22pm UTC](https://discourse.julialang.org/t/announcing-neptune-jl-now-updated-to-multi-line-cells/54088 "2022-01-25T12:22:05Z")

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Neptune.jl is effectively a lightweight variation on the Jupyter notebook theme, but written entirely in Julia, based on the package Pluto.jl, but not tied to the ‘reactive execution’ mission being pursued by the develop…

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## [KenCarp47 is giving wrong result no matter how tight the tolerance is. Is there a way to resolve this?](https://discourse.julialang.org/t/kencarp47-is-giving-wrong-result-no-matter-how-tight-the-tolerance-is-is-there-a-way-to-resolve-this/75078)

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**Author:** [@Shashank](https://discourse.julialang.org/u/Shashank)\
**Replies:** 29\
**Last updated:** [January 25, 2022, 12:16pm UTC](https://discourse.julialang.org/t/kencarp47-is-giving-wrong-result-no-matter-how-tight-the-tolerance-is-is-there-a-way-to-resolve-this/75078 "2022-01-25T12:16:53Z")

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I am trying to solve a set of coupled nonlinear equations, and the system has physical instability. The equations of motion are i\\frac{d\\rho(\\cos\\theta,t)}{dt}=\[H,\\rho(\\cos\\theta,t)\] i\\frac{d\\bar{\\rho}(\\cos\\theta,t)}{d…

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## [Makie (and Julia) do not automatically typecast obvious numerical representations](https://discourse.julialang.org/t/makie-and-julia-do-not-automatically-typecast-obvious-numerical-representations/75148)

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**Author:** [@filchristou](https://discourse.julialang.org/u/filchristou)\
**Replies:** 6\
**Last updated:** [January 25, 2022, 11:46am UTC](https://discourse.julialang.org/t/makie-and-julia-do-not-automatically-typecast-obvious-numerical-representations/75148 "2022-01-25T11:46:16Z")

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I have experienced that Julia is not very generous with automatic typecasting (or type conversion). e.g. f(x::Int) = x f(1.0) ERROR: MethodError: no method matching f(::Float64) Closest candidates are: f(::Int64) at …

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## [Embedding multiple versions of Julia in a single C application](https://discourse.julialang.org/t/embedding-multiple-versions-of-julia-in-a-single-c-application/75133)

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**Author:** [@cariocecus](https://discourse.julialang.org/u/cariocecus)\
**Replies:** 6\
**Last updated:** [January 25, 2022, 11:38am UTC](https://discourse.julialang.org/t/embedding-multiple-versions-of-julia-in-a-single-c-application/75133 "2022-01-25T11:38:13Z")

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Dear Julia community, I have a C application that calls code that was developed in Julia 0.3.12 (hereafter called old code). I do this by following the guidelines of the Embedding Julia section of the manual. Now I nee…

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## [Docs-specific dependencies - should I use a separate environment?](https://discourse.julialang.org/t/docs-specific-dependencies-should-i-use-a-separate-environment/75159)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 4\
**Last updated:** [January 25, 2022, 10:08am UTC](https://discourse.julialang.org/t/docs-specific-dependencies-should-i-use-a-separate-environment/75159 "2022-01-25T10:08:44Z")

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I’ve been working on my first package for counterfactual explanations and algorithmic recourse in Julia. To create tutorials as part of the documentation I have been using packages that are not dependencies of the packag…

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## [Subsetting dataframe with multiple conditions](https://discourse.julialang.org/t/subsetting-dataframe-with-multiple-conditions/75160)

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**Author:** [@lobshi](https://discourse.julialang.org/u/lobshi)\
**Replies:** 2\
**Last updated:** [January 25, 2022, 9:59am UTC](https://discourse.julialang.org/t/subsetting-dataframe-with-multiple-conditions/75160 "2022-01-25T09:59:19Z")

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Why should i wrap every condition in a pair of parentheses when subsetting data? Example dataframe as below: d = DataFrame(a = \[1, 2, 3\], b = \["x", "y", "z"\]) d2 = d\[(d.a .\> 1) .| (d.b == "z"), :\] If I remove parenthes…

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## [Missing line from deffeqflux blog post](https://discourse.julialang.org/t/missing-line-from-deffeqflux-blog-post/75141)

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**Author:** [@pl-ai](https://discourse.julialang.org/u/pl-ai)\
**Replies:** 1\
**Last updated:** [January 25, 2022, 8:10am UTC](https://discourse.julialang.org/t/missing-line-from-deffeqflux-blog-post/75141 "2022-01-25T08:10:13Z")

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In the blog post linked from the diffeqflux package (DiffEqFlux.jl – A Julia Library for Neural Differential Equations), there is this section down the page: Notice that we are not learning a solution to the ODE. Instea…

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## [\`VectorContinuousCallback\` not picking up threshold](https://discourse.julialang.org/t/vectorcontinuouscallback-not-picking-up-threshold/74596)

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**Author:** [@colebrookson](https://discourse.julialang.org/u/colebrookson)\
**Replies:** 1\
**Last updated:** [January 25, 2022, 6:14am UTC](https://discourse.julialang.org/t/vectorcontinuouscallback-not-picking-up-threshold/74596 "2022-01-25T06:14:32Z")

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I’m having trouble getting VectorContinuousCallback to work as desired and I’m not sure what I’m doing wrong. I have a large system of equations, and essentially, any time any of the values cross some threshold value (in…

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## [Why isn't \`size\` always inferred to be an Integer?](https://discourse.julialang.org/t/why-isnt-size-always-inferred-to-be-an-integer/75139)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 24\
**Last updated:** [January 24, 2022, 11:57pm UTC](https://discourse.julialang.org/t/why-isnt-size-always-inferred-to-be-an-integer/75139 "2022-01-24T23:57:09Z")

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I have also spent an endless number of hours in SnooptCompile to achieve improvements of 1-2 seconds in compile time. One thing that I really can’t understand is why taking the size or length of a var that is Any returns…

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## [Sinc Interpolation based on FFT](https://discourse.julialang.org/t/sinc-interpolation-based-on-fft/52512)

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**Author:** [@roflmaostc](https://discourse.julialang.org/u/roflmaostc)\
**Replies:** 92\
**Last updated:** [January 24, 2022, 10:18pm UTC](https://discourse.julialang.org/t/sinc-interpolation-based-on-fft/52512 "2022-01-24T22:18:47Z")

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Hey, I was trying to implement a sinc interpolation based on FFTs. One way (as far as I know) is to zero pad the frequency spectrum and calculate the IFFT of the spectrum to get a sinc interpolated signal. I ended up …

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## [CUDA aware MPI works on system but not for Julia](https://discourse.julialang.org/t/cuda-aware-mpi-works-on-system-but-not-for-julia/75060)

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**Author:** [@Chiil](https://discourse.julialang.org/u/Chiil)\
**Replies:** 30\
**Last updated:** [January 24, 2022, 10:15pm UTC](https://discourse.julialang.org/t/cuda-aware-mpi-works-on-system-but-not-for-julia/75060 "2022-01-24T22:15:10Z")

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I have problems getting CUDA-aware MPI running in Julia. I have a C++ example that works perfectly if I run it with mpiexec -n 2 ./alltoall\_test. The equivalent Julia code run with mpiexec -n 2 julia alltoall\_test.jl fai…

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## [Training Deep Neural Network using Data Parallel?](https://discourse.julialang.org/t/training-deep-neural-network-using-data-parallel/75079)

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**Author:** [@rkube](https://discourse.julialang.org/u/rkube)\
**Replies:** 5\
**Last updated:** [January 24, 2022, 9:08pm UTC](https://discourse.julialang.org/t/training-deep-neural-network-using-data-parallel/75079 "2022-01-24T21:08:19Z")

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Hi, I need to train some simpler networks on large datasets and would like to use multiple GPUs for training. Is there a tutorial or writeup on how to do this in Julia? I know about this one in torch: Multi-GPU Examples…

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## [ANN: BitIntegers.jl (Int256, ...) and BitFloats.jl (Float80, Float128)](https://discourse.julialang.org/t/ann-bitintegers-jl-int256-and-bitfloats-jl-float80-float128/15935)

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**Author:** [@rfourquet](https://discourse.julialang.org/u/rfourquet)\
**Replies:** 8\
**Last updated:** [January 24, 2022, 8:22pm UTC](https://discourse.julialang.org/t/ann-bitintegers-jl-int256-and-bitfloats-jl-float80-float128/15935 "2022-01-24T20:22:04Z")

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I’m glad to present two new registered packages which add more “native-like” types to Julia, mostly implemented in the same way as Base builtin integer and floating point types. Both packages can lead to segfaults that…

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## [Creating a DataFrame column as the running mean of another column](https://discourse.julialang.org/t/creating-a-dataframe-column-as-the-running-mean-of-another-column/75058)

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**Author:** [@StatisticalMouse](https://discourse.julialang.org/u/StatisticalMouse)\
**Replies:** 5\
**Last updated:** [January 24, 2022, 7:35pm UTC](https://discourse.julialang.org/t/creating-a-dataframe-column-as-the-running-mean-of-another-column/75058 "2022-01-24T19:35:42Z")

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The original code for this is a Pluto notebook, and the code in this post is supposed to be three notebook cells. The code works, and I’m pretty sure there’s a nicer syntax for the cell three, but I just can’t seem to fi…

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## [Best Julian way to copy many files?](https://discourse.julialang.org/t/best-julian-way-to-copy-many-files/75142)

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**Author:** [@chowerth](https://discourse.julialang.org/u/chowerth)\
**Replies:** 2\
**Last updated:** [January 24, 2022, 7:24pm UTC](https://discourse.julialang.org/t/best-julian-way-to-copy-many-files/75142 "2022-01-24T19:24:00Z")

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Hello. I’m wondering what is the best Julian way to copy files. My particular use case is I have a large number of files (of varying size) and I’m automating their data cleaning and backup process. Without going into gr…

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## [Bravais lattice with a gaussian at every site](https://discourse.julialang.org/t/bravais-lattice-with-a-gaussian-at-every-site/75055)

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**Author:** [@ash](https://discourse.julialang.org/u/ash)\
**Replies:** 9\
**Last updated:** [January 24, 2022, 7:16pm UTC](https://discourse.julialang.org/t/bravais-lattice-with-a-gaussian-at-every-site/75055 "2022-01-24T19:16:45Z")

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I am trying to generate a numerical initial condition for a PDE that looks like this: it is a Bravais lattice, with a gaussian at each site (in 2D). This is not difficult to do by hand for a square lattice with two atoms…

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## [MOI.SingleVariable-in-MOI.Integer constraints are not supported by Ipopt](https://discourse.julialang.org/t/moi-singlevariable-in-moi-integer-constraints-are-not-supported-by-ipopt/75101)

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**Author:** [@oxox](https://discourse.julialang.org/u/oxox)\
**Replies:** 4\
**Last updated:** [January 24, 2022, 6:28pm UTC](https://discourse.julialang.org/t/moi-singlevariable-in-moi-integer-constraints-are-not-supported-by-ipopt/75101 "2022-01-24T18:28:21Z")

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Hi,I’m a beginner with JuMP and have some problems using the IPOPT solver. When using the IPOPT solver, there is no way to create an integer variable, an error occurs. Can someone help me？？？Thanks a lot. using JuMP u…

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## [DifferentialEquationsjl with ForwardDiff.jl](https://discourse.julialang.org/t/differentialequationsjl-with-forwarddiff-jl/75135)

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**Author:** [@Yinmin\_Liu](https://discourse.julialang.org/u/Yinmin_Liu)\
**Replies:** 4\
**Last updated:** [January 24, 2022, 5:56pm UTC](https://discourse.julialang.org/t/differentialequationsjl-with-forwarddiff-jl/75135 "2022-01-24T17:56:22Z")

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I am trying to solve ODEs using DifferentialEquationsjl while generating jacobian using ForwardDiff.jl. My current code looks like the following: It does work, but it is even slower than when I define the function a…

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## [Languageserver referencing old/non-existing version](https://discourse.julialang.org/t/languageserver-referencing-old-non-existing-version/75067)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 4\
**Last updated:** [January 24, 2022, 5:54pm UTC](https://discourse.julialang.org/t/languageserver-referencing-old-non-existing-version/75067 "2022-01-24T17:54:48Z")

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When I hover over a function in VSCode, shown code locations also include old, already removed versions of Julia. So instead of actual Julia-1.7.0 it refers to Julia-1.7.0-rc1. A grep over.julia shows some hits, e.g. i…

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## [Are Value types the correct solution for me? (as parameters that choose the algorithm)](https://discourse.julialang.org/t/are-value-types-the-correct-solution-for-me-as-parameters-that-choose-the-algorithm/75069)

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**Author:** [@Elyco](https://discourse.julialang.org/u/Elyco)\
**Replies:** 4\
**Last updated:** [January 24, 2022, 5:51pm UTC](https://discourse.julialang.org/t/are-value-types-the-correct-solution-for-me-as-parameters-that-choose-the-algorithm/75069 "2022-01-24T17:51:37Z")

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Hi, I need some help in understanding whether value types are the right solution for my situation. I have some simulation that can be solved in different ways. When I run it, I can choose different parameters such as t…

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## [Scroll zoom in Plots.jl](https://discourse.julialang.org/t/scroll-zoom-in-plots-jl/75134)

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**Author:** [@vembha](https://discourse.julialang.org/u/vembha)\
**Replies:** 4\
**Last updated:** [January 24, 2022, 5:51pm UTC](https://discourse.julialang.org/t/scroll-zoom-in-plots-jl/75134 "2022-01-24T17:51:37Z")

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Hello. I am a relatively new user of Julia on VSCode. I remember that till a couple of months ago, Plots.jl was allowing me to zoom into the plots using the scroll wheel of my mouse. Looks like after some package/VSCode …

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## [GitHub GMT.jl documentation broken and have no idea on how to fix](https://discourse.julialang.org/t/github-gmt-jl-documentation-broken-and-have-no-idea-on-how-to-fix/74987)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 1\
**Last updated:** [January 24, 2022, 3:31pm UTC](https://discourse.julialang.org/t/github-gmt-jl-documentation-broken-and-have-no-idea-on-how-to-fix/74987 "2022-01-24T15:31:41Z")

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Hi, I’m totally lost on why the documentation of GMT.jl is now broken. Problems start to arise when, for some unknown reason the Linux CI build started to fail. ERROR: LoadError: could not load library "/home/runner/gm…

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## [Hyperlink to a section](https://discourse.julialang.org/t/hyperlink-to-a-section/74426)

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**Author:** [@dmsorokin](https://discourse.julialang.org/u/dmsorokin)\
**Replies:** 2\
**Last updated:** [January 24, 2022, 3:30pm UTC](https://discourse.julialang.org/t/hyperlink-to-a-section/74426 "2022-01-24T15:30:10Z")

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Hi everyone. I am trying to create a hyperlink to a section within the same pluto document. Others have asked more complicated questions about hyperlinks here, but this simple question seems to not be addressed anywhere. …

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## [Is Gtk.jl mature and stable on macOS?](https://discourse.julialang.org/t/is-gtk-jl-mature-and-stable-on-macos/75000)

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**Author:** [@Erik\_Engheim](https://discourse.julialang.org/u/Erik_Engheim)\
**Replies:** 6\
**Last updated:** [January 24, 2022, 2:47pm UTC](https://discourse.julialang.org/t/is-gtk-jl-mature-and-stable-on-macos/75000 "2022-01-24T14:47:25Z")

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I am trying to determine what GUI toolkit to use in Julia. I want to avoid pursuing a toolkit which is unstable and prone to crashes forcing me to switch toolkit midstream. I am interested in using Gtk but I know from t…

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## [MLStyle variadic match ast](https://discourse.julialang.org/t/mlstyle-variadic-match-ast/75021)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 1\
**Last updated:** [January 24, 2022, 2:42pm UTC](https://discourse.julialang.org/t/mlstyle-variadic-match-ast/75021 "2022-01-24T14:42:43Z")

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This code works using MLStyle, MLStyle.Modules.AST @match :( (a::Foo, b::Bar) ) begin :($n1::$t1, $n2::$t2) =\> (n1,n2) end but I want to do this with arbitrarily many variables, not just 2. I tried using ... but it…

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