# Latest

**URL:** https://discourse.julialang.org/latest.md?page=882

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

**Page:** 883

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## [libGL error: MESA... after (unintended) Plots update](https://discourse.julialang.org/t/libgl-error-mesa-after-unintended-plots-update/48265)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 8\
**Last updated:** [October 27, 2022, 3:19pm UTC](https://discourse.julialang.org/t/libgl-error-mesa-after-unintended-plots-update/48265 "2022-10-27T15:19:08Z")

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Today, after installing some new packages (Ipopt and JuMP), for some reason Plots got updated as well. After that, every time I plot something, I get these errors. Any tip on how to get rid of them? (the plots themselves…

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## [After using VS Code debugger (compiled mode), error message of Optimization.jl appeared for a previously working code](https://discourse.julialang.org/t/after-using-vs-code-debugger-compiled-mode-error-message-of-optimization-jl-appeared-for-a-previously-working-code/89374)

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**Author:** [@tlyim](https://discourse.julialang.org/u/tlyim)\
**Replies:** 0\
**Last updated:** [October 27, 2022, 2:12pm UTC](https://discourse.julialang.org/t/after-using-vs-code-debugger-compiled-mode-error-message-of-optimization-jl-appeared-for-a-previously-working-code/89374 "2022-10-27T14:12:56Z")

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I have a working Julia code, which was converted from a working Matlab code. There were some minor differences in the results. I wanted to confirm whether they were due to an imperfect conversion of Matlab’s fmincon func…

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## [How can I split large data using a faster and more efficient function (data science)?](https://discourse.julialang.org/t/how-can-i-split-large-data-using-a-faster-and-more-efficient-function-data-science/89287)

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**Author:** [@bosamu05](https://discourse.julialang.org/u/bosamu05)\
**Replies:** 9\
**Last updated:** [October 27, 2022, 1:57pm UTC](https://discourse.julialang.org/t/how-can-i-split-large-data-using-a-faster-and-more-efficient-function-data-science/89287 "2022-10-27T13:57:11Z")

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Hi everyone I am a new user of Julia. I want to parse data from a file with over 50 GB. I have used CSV.file to read a set of data (every 427,905 lines) using skipto=start\_m,limit=NumberEffects,ntasks=1. The file conta…

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## [SDP Sum of Squares optimization](https://discourse.julialang.org/t/sdp-sum-of-squares-optimization/88487)

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**Author:** [@parf](https://discourse.julialang.org/u/parf)\
**Replies:** 10\
**Last updated:** [October 27, 2022, 1:45pm UTC](https://discourse.julialang.org/t/sdp-sum-of-squares-optimization/88487 "2022-10-27T13:45:08Z")

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I am trying to solve the following optimization problem: using DynamicPolynomials using SumOfSquares using SDPAFamily χ=1.0 @polyvar x1 x2 x3 x4 f = \[2\*x1\*x4 - 2\*x2\*x3 - x1, -2\*x1\*x3 - 2\*x2\*x4 - x2, 2\*x1\*x2,…

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## [When I using jupyter Julia 1.8.2 , it often lose connection](https://discourse.julialang.org/t/when-i-using-jupyter-julia-1-8-2-it-often-lose-connection/89354)

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**Author:** [@KarryMa](https://discourse.julialang.org/u/KarryMa)\
**Replies:** 2\
**Last updated:** [October 27, 2022, 1:23pm UTC](https://discourse.julialang.org/t/when-i-using-jupyter-julia-1-8-2-it-often-lose-connection/89354 "2022-10-27T13:23:54Z")

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When I open a file of Julia, after a few seconds, it would lose connection. Just say The service has an error. And even Failed to create a notebook

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## [Slowdown due to subnormal float, coming from neural net training](https://discourse.julialang.org/t/slowdown-due-to-subnormal-float-coming-from-neural-net-training/89286)

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**Author:** [@Fabrice\_Rosay](https://discourse.julialang.org/u/Fabrice_Rosay)\
**Replies:** 20\
**Last updated:** [October 27, 2022, 11:03am UTC](https://discourse.julialang.org/t/slowdown-due-to-subnormal-float-coming-from-neural-net-training/89286 "2022-10-27T11:03:04Z")

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Here is a minimal working example function mygemavx!(C, A, B, bias) @turbo for m ∈ axes(A,1) Cmk = bias\[m\] for k ∈ axes(A,2) Cmk += A\[m,k\] \* B\[k\] end C\[m\] = Cmk end C end A1=zeros…

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## [Drawing arrows on axes](https://discourse.julialang.org/t/drawing-arrows-on-axes/30341)

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**Author:** [@squirrel](https://discourse.julialang.org/u/squirrel)\
**Replies:** 9\
**Last updated:** [October 27, 2022, 12:35pm UTC](https://discourse.julialang.org/t/drawing-arrows-on-axes/30341 "2022-10-27T12:35:26Z")

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I’m trying to add arrows to my axes, but it isn’t working. I have using Plots x(u) = u y(u) = sqrt(u) y2(u) = -sqrt(u) plot(x, \[y, y2\], 0, 5, framestyle = :origin, legend = :none, linecolor = :blue, dr…

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## [PythonCall - from X import Y](https://discourse.julialang.org/t/pythoncall-from-x-import-y/89353)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 3\
**Last updated:** [October 27, 2022, 11:20am UTC](https://discourse.julialang.org/t/pythoncall-from-x-import-y/89353 "2022-10-27T11:20:44Z")

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When I want to import a module X, I can call using PythonCall pyimport("X") I want to import Image from PIL, which in python is done by from PIL import Image However, I can not access Image from PIL directly: \>\>\> i…

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## [\[ANN\] DelayedEvaluation.jl: A package fix function arguments with \`getindex\` syntax](https://discourse.julialang.org/t/ann-delayedevaluation-jl-a-package-fix-function-arguments-with-getindex-syntax/89358)

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**Author:** [@flipgthb](https://discourse.julialang.org/u/flipgthb)\
**Replies:** 1\
**Last updated:** [October 27, 2022, 11:17am UTC](https://discourse.julialang.org/t/ann-delayedevaluation-jl-a-package-fix-function-arguments-with-getindex-syntax/89358 "2022-10-27T11:17:58Z")

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Hello all, I created a small package extending the functionality of Base.Fix1 and Base.Fix2 to any function and provides a syntax analogous to array or DataFrame indexing to fix function arguments using ! (instead of :)…

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## [ODE terms dependent on time of events](https://discourse.julialang.org/t/ode-terms-dependent-on-time-of-events/88962)

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**Author:** [@KalelR](https://discourse.julialang.org/u/KalelR)\
**Replies:** 5\
**Last updated:** [October 27, 2022, 10:13am UTC](https://discourse.julialang.org/t/ode-terms-dependent-on-time-of-events/88962 "2022-10-27T10:13:26Z")

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Hey there I would like some advice for implementing efficient code for a spiking neuron network with coupling that depends on spike times. When a neuron in the model spikes (one of its variables, the membrane potential,…

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## [Does Julia's speed get slower over time in REPL?](https://discourse.julialang.org/t/does-julias-speed-get-slower-over-time-in-repl/89066)

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**Author:** [@tiZ](https://discourse.julialang.org/u/tiZ)\
**Replies:** 4\
**Last updated:** [October 27, 2022, 4:25am UTC](https://discourse.julialang.org/t/does-julias-speed-get-slower-over-time-in-repl/89066 "2022-10-27T04:25:36Z")

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When I’m on a Julia REPL that has been running for a while, I find that julia will slow down, but if I restart the REPL, the speed returns to normal. For example, I have a function denoted f(x), that takes 15 minutes in…

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## [IncorrectCallArgs warning when using outerjoin() in VSCode linter](https://discourse.julialang.org/t/incorrectcallargs-warning-when-using-outerjoin-in-vscode-linter/89341)

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**Author:** [@rock](https://discourse.julialang.org/u/rock)\
**Replies:** 7\
**Last updated:** [October 27, 2022, 9:29am UTC](https://discourse.julialang.org/t/incorrectcallargs-warning-when-using-outerjoin-in-vscode-linter/89341 "2022-10-27T09:29:38Z")

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In VS Code, I am getting a warning whenever I use outerjoin() on two DataFrames. For example, I get an error using the following example from the documentation: name = DataFrame(ID=\[1, 2, 3\], Name=\["John Doe", "Jane Doe…

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## [Error when Pkg.add("Julia")](https://discourse.julialang.org/t/error-when-pkg-add-julia/89351)

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**Author:** [@KarryMa](https://discourse.julialang.org/u/KarryMa)\
**Replies:** 6\
**Last updated:** [October 27, 2022, 9:27am UTC](https://discourse.julialang.org/t/error-when-pkg-add-julia/89351 "2022-10-27T09:27:34Z")

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I’m really new here. import Pkg Pkg.add(“Julia”) But get the error. ERROR: The following package names could not be resolved: Julia (not found in project, manifest or registry) Suggestions: julia JuliaZH JuliaDB …

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## [\[ANN\] ConformalPrediction.jl: Uncertainty quantification through conformal prediction for machine learning models trained in MLJ](https://discourse.julialang.org/t/ann-conformalprediction-jl-uncertainty-quantification-through-conformal-prediction-for-machine-learning-models-trained-in-mlj/89348)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 1\
**Last updated:** [October 27, 2022, 8:52am UTC](https://discourse.julialang.org/t/ann-conformalprediction-jl-uncertainty-quantification-through-conformal-prediction-for-machine-learning-models-trained-in-mlj/89348 "2022-10-27T08:52:55Z")

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Very excited to announce ConformalPrediction.jl :tada: ConformalPrediction ConformalPrediction.jl is a package for Uncertainty Quantification (UQ) through Conformal Prediction (CP) in Julia. It is designed to wo…

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## [Shuffling multiple N-arrays over a given dimension](https://discourse.julialang.org/t/shuffling-multiple-n-arrays-over-a-given-dimension/59206)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [October 27, 2022, 8:19am UTC](https://discourse.julialang.org/t/shuffling-multiple-n-arrays-over-a-given-dimension/59206 "2022-10-27T08:19:51Z")

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Sometimes we have the need to shuffle a given list of arrays over a given dimension, but keeping the relative order on that dimension ( e.g. when we have in machine learning to shuffle features and label matrices over th…

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## [Error in DynamicPolynomials?](https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196)

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**Author:** [@mhar](https://discourse.julialang.org/u/mhar)\
**Replies:** 1\
**Last updated:** [October 24, 2022, 4:31pm UTC](https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196 "2022-10-24T16:31:56Z")

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The following code used to work, but I’m having an issue with it now: using DynamicPolynomials @polyvar var1 var2 v = randn(3); \_mons = monomials(\[var1, var2\], length(v) - 1); p = sum(\_mons .\* v) p + p ERROR: AssertionE…

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## [Change default resolution in Theme() and Mac retina displays](https://discourse.julialang.org/t/change-default-resolution-in-theme-and-mac-retina-displays/89345)

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**Author:** [@garrek](https://discourse.julialang.org/u/garrek)\
**Replies:** 2\
**Last updated:** [October 27, 2022, 6:24am UTC](https://discourse.julialang.org/t/change-default-resolution-in-theme-and-mac-retina-displays/89345 "2022-10-27T06:24:22Z")

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Is there a way to set the default resolution in a Theme() in Makie? I want to set a default theme for Retina displays on Mac, since everything is too small with the default. I can set font size, line width, etc., but can…

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## [Initialize nested arrays](https://discourse.julialang.org/t/initialize-nested-arrays/89284)

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**Author:** [@ManuelFossa](https://discourse.julialang.org/u/ManuelFossa)\
**Replies:** 4\
**Last updated:** [October 27, 2022, 5:32am UTC](https://discourse.julialang.org/t/initialize-nested-arrays/89284 "2022-10-27T05:32:44Z")

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I need to initialize a Matrix, containing Matrices, the latter containing a Vector or Matrices. I did something like this: sizeMat11 = 2 sizeMat12 = 3 sizeMat21 = 5 sizeMat22 = 6 sizeVec31 = 9 struct SomeStruct x:…

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## [Should the eachindex function be part of the Indexing interface?](https://discourse.julialang.org/t/should-the-eachindex-function-be-part-of-the-indexing-interface/89296)

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**Author:** [@eliascarv](https://discourse.julialang.org/u/eliascarv)\
**Replies:** 3\
**Last updated:** [October 27, 2022, 4:08am UTC](https://discourse.julialang.org/t/should-the-eachindex-function-be-part-of-the-indexing-interface/89296 "2022-10-27T04:08:47Z")

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Currently, the Indexing interface is composed of 4 functions: However, among these functions, there is not one that returns the valid indexes of the indexable object. In its documentation, it is shown that the eachi…

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## [Most efficient way to add new columns in each SubDataFrame of a GroupDataFrame](https://discourse.julialang.org/t/most-efficient-way-to-add-new-columns-in-each-subdataframe-of-a-groupdataframe/89272)

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**Author:** [@phantom](https://discourse.julialang.org/u/phantom)\
**Replies:** 6\
**Last updated:** [October 27, 2022, 2:08am UTC](https://discourse.julialang.org/t/most-efficient-way-to-add-new-columns-in-each-subdataframe-of-a-groupdataframe/89272 "2022-10-27T02:08:14Z")

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Sorry kind of a beginners question again. Suppose I have a large GroupDataFrame and I would like to add columns to each SubDataFrame in the Group. function build(GDF) for k = eachindex(GDF) GDF\[k\].newcol1 = fun…

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## [Translating a basic MNIST tensorflow network into an MLJFlux builder](https://discourse.julialang.org/t/translating-a-basic-mnist-tensorflow-network-into-an-mljflux-builder/89338)

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**Author:** [@ablaom](https://discourse.julialang.org/u/ablaom)\
**Replies:** 1\
**Last updated:** [October 27, 2022, 12:08am UTC](https://discourse.julialang.org/t/translating-a-basic-mnist-tensorflow-network-into-an-mljflux-builder/89338 "2022-10-27T00:08:20Z")

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On slack I have been asked: How does one translate the following into MLJFlux. The code is from this tensorflow tutorial on the MNIST dataset for beginners. model = tf.keras.models.Sequential(\[ tf.keras.layers.Flat…

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## [Polyhedron of JuMP model with Polyhedra or Lazyset](https://discourse.julialang.org/t/polyhedron-of-jump-model-with-polyhedra-or-lazyset/89218)

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**Author:** [@papar](https://discourse.julialang.org/u/papar)\
**Replies:** 7\
**Last updated:** [October 26, 2022, 10:53pm UTC](https://discourse.julialang.org/t/polyhedron-of-jump-model-with-polyhedra-or-lazyset/89218 "2022-10-26T22:53:48Z")

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Hello, I want to plot a 3D polyhedron of a JuMP model for education purposes. I have seen these packages Polyhedra and LazySets, but I am unsure how to convert a JuMP model. I believe it requires projection/elimination.…

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## [Mojibake on github for Jupyter notebooks](https://discourse.julialang.org/t/mojibake-on-github-for-jupyter-notebooks/89320)

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**Author:** [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Replies:** 4\
**Last updated:** [October 26, 2022, 9:43pm UTC](https://discourse.julialang.org/t/mojibake-on-github-for-jupyter-notebooks/89320 "2022-10-26T21:43:58Z")

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Has anyone else noticed that Github is suddenly rendering any Unicode characters in Jupyter notebooks as mojibake (garbled characters like “—Ô), e.g. in this notebook for my class? Is there any way to fix it? I d…

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## [Sqrt not giving the correct value](https://discourse.julialang.org/t/sqrt-not-giving-the-correct-value/89318)

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**Author:** [@Giulianno\_G](https://discourse.julialang.org/u/Giulianno_G)\
**Replies:** 5\
**Last updated:** [October 26, 2022, 8:28pm UTC](https://discourse.julialang.org/t/sqrt-not-giving-the-correct-value/89318 "2022-10-26T20:28:57Z")

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Hello, I’m new to Julia and I was trying to use for Fermat Factoring problem I’m having issues with the sqrt not returning the correct value function fermat(n::Int64) x = isqrt(n); y = 0.1 while y%1 != 0 …

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## [\`cond\` and \`condskeel\`](https://discourse.julialang.org/t/cond-and-condskeel/89328)

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**Author:** [@nchisholm](https://discourse.julialang.org/u/nchisholm)\
**Replies:** 1\
**Last updated:** [October 26, 2022, 8:28pm UTC](https://discourse.julialang.org/t/cond-and-condskeel/89328 "2022-10-26T20:28:00Z")

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I am wondering about the usage of cond versus condskeel. I am familiar with the condition number, but not as much with the Skeel condition number. I have found that the two functions generally produce numbers of the sa…

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## [Adding a function nthcomb() to Combinatorics.jl](https://discourse.julialang.org/t/adding-a-function-nthcomb-to-combinatorics-jl/89326)

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**Author:** [@ajloza](https://discourse.julialang.org/u/ajloza)\
**Replies:** 2\
**Last updated:** [October 26, 2022, 8:01pm UTC](https://discourse.julialang.org/t/adding-a-function-nthcomb-to-combinatorics-jl/89326 "2022-10-26T20:01:57Z")

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I recently had a project that required writing code for generating Nth lexicographic combinations of size k. Combinatorics.jl has nthperm, but not the equivalent for combinations. If there is interest in adding this func…

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## [Diffeq ContinuousCallback "not callable" errors](https://discourse.julialang.org/t/diffeq-continuouscallback-not-callable-errors/88198)

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**Author:** [@John\_Boik](https://discourse.julialang.org/u/John_Boik)\
**Replies:** 9\
**Last updated:** [October 26, 2022, 7:42pm UTC](https://discourse.julialang.org/t/diffeq-continuouscallback-not-callable-errors/88198 "2022-10-26T19:42:36Z")

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My use of ContinuousCallback from DifferentialEquations.jl is throwing an error and I don’t know why. Any help would be appreciated. The short version of the error is: LoadError: MethodError: objects of type SciMLBase.C…

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## [How to define a symbolic vector using for loop with Symbolics.jl?](https://discourse.julialang.org/t/how-to-define-a-symbolic-vector-using-for-loop-with-symbolics-jl/89262)

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**Author:** [@xyli](https://discourse.julialang.org/u/xyli)\
**Replies:** 7\
**Last updated:** [October 26, 2022, 7:32pm UTC](https://discourse.julialang.org/t/how-to-define-a-symbolic-vector-using-for-loop-with-symbolics-jl/89262 "2022-10-26T19:32:28Z")

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Dear all, How to define a symbolic vector using for loop with Symbolics.jl? For example, x=\[x1, x2, x3, x4, …, x100\], where xi are all variables defined using @variables. It can be easily done using sympy.jl as julia\>…

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## [Using CLang version 14](https://discourse.julialang.org/t/using-clang-version-14/89321)

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**Author:** [@pixel27](https://discourse.julialang.org/u/pixel27)\
**Replies:** 0\
**Last updated:** [October 26, 2022, 7:11pm UTC](https://discourse.julialang.org/t/using-clang-version-14/89321 "2022-10-26T19:11:25Z")

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I would like to use CLang version 14 to parse some C++ files. The C++ files I would like to parse are using the “module” feature added in C++20 and it doesn’t appear that version 13 understands the module keyword. I bel…

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## [Questions about csv（How to write to csv faster）](https://discourse.julialang.org/t/questions-about-csv-how-to-write-to-csv-faster/89247)

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**Author:** [@zhangchunyong](https://discourse.julialang.org/u/zhangchunyong)\
**Replies:** 10\
**Last updated:** [October 26, 2022, 6:21pm UTC](https://discourse.julialang.org/t/questions-about-csv-how-to-write-to-csv-faster/89247 "2022-10-26T18:21:32Z")

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I have a huge dataframe which has 26M rows.How do I write it to a csv file faster and comsume fewer memories? julia\> pdpdpd=vcat(pd,pd,pd) 26590302×6 DataFrame Row │ chr position pdr discordant sum …

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