# Latest

**URL:** https://discourse.julialang.org/latest.md?page=525

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

**Page:** 526

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## [Hide default constructor for a struct](https://discourse.julialang.org/t/hide-default-constructor-for-a-struct/89064)

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**Author:** [@prittjam](https://discourse.julialang.org/u/prittjam)\
**Replies:** 13\
**Last updated:** [December 21, 2023, 12:53pm UTC](https://discourse.julialang.org/t/hide-default-constructor-for-a-struct/89064 "2023-12-21T12:53:49Z")

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Is there a way to hide a default constructor for a struct so that it is not callable? Thanks.

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## [Lining up zeros on plot with 2 y axes](https://discourse.julialang.org/t/lining-up-zeros-on-plot-with-2-y-axes/107736)

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**Author:** [@aoifehealy](https://discourse.julialang.org/u/aoifehealy)\
**Replies:** 7\
**Last updated:** [December 21, 2023, 11:28am UTC](https://discourse.julialang.org/t/lining-up-zeros-on-plot-with-2-y-axes/107736 "2023-12-21T11:28:26Z")

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Hi there, I am plotting 2 different datasets on the same plot, but using different scaled y axes, using the following code: plot(ShiSimpleSolV, idxs = \[circ\_sys.MV.q\]) plot!(twinx(), ShiSimpleSolV, idxs = \[circ\_sys.MV…

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## [Dates in DataFrames](https://discourse.julialang.org/t/dates-in-dataframes/107887)

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**Author:** [@David\_Annetts](https://discourse.julialang.org/u/David_Annetts)\
**Replies:** 1\
**Last updated:** [December 21, 2023, 3:07am UTC](https://discourse.julialang.org/t/dates-in-dataframes/107887 "2023-12-21T03:07:53Z")

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Hi, I (think I) have a vector of dates in rdat. At least, typeof.(rdat) returns a lot of Date. So I’m confused as to why tmp = DataFrame(td = rdat) returns a DataFrame with the column td listed as a vector of type An…

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## [Convert nl file to mps file using JuMP](https://discourse.julialang.org/t/convert-nl-file-to-mps-file-using-jump/107885)

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**Author:** [@rlacjfjin](https://discourse.julialang.org/u/rlacjfjin)\
**Replies:** 8\
**Last updated:** [December 21, 2023, 3:00am UTC](https://discourse.julialang.org/t/convert-nl-file-to-mps-file-using-jump/107885 "2023-12-21T03:00:25Z")

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As in question: Why I can't read nl file with other solver · Issue #3637 · jump-dev/JuMP.jl · GitHub When I using the code: model = read\_from\_file("my\_model.nl"; use\_nlp\_block = false) A JuMP Model Maximization problem…

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## [Efficiently check if a sparse vector is a column of a sparse matrix](https://discourse.julialang.org/t/efficiently-check-if-a-sparse-vector-is-a-column-of-a-sparse-matrix/107861)

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**Author:** [@max29](https://discourse.julialang.org/u/max29)\
**Replies:** 13\
**Last updated:** [December 21, 2023, 2:57am UTC](https://discourse.julialang.org/t/efficiently-check-if-a-sparse-vector-is-a-column-of-a-sparse-matrix/107861 "2023-12-21T02:57:47Z")

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I have a sparse matrix A and a sparse vector x and want to check if the vector is a column of the matrix. using SparseArrays, BenchmarkTools A = spdiagm(1:1000); x = sparsevec(\[950\],\[950\],1000); B = Array(A); # dense y…

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## [Possible performance improvements for \`deepcopy\`?](https://discourse.julialang.org/t/possible-performance-improvements-for-deepcopy/107719)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 4\
**Last updated:** [December 21, 2023, 1:09am UTC](https://discourse.julialang.org/t/possible-performance-improvements-for-deepcopy/107719 "2023-12-21T01:09:42Z")

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I created this small package here GitHub - Tortar/FastDeepCopy.jl which outperform the current deepcopy implementation by quite a bit, for a vector of mutable structs it is more than 200 times faster as you can see in th…

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## [Broadcast inside of \`@mtkmodel\` macro causes precompilation failures when put into a package](https://discourse.julialang.org/t/broadcast-inside-of-mtkmodel-macro-causes-precompilation-failures-when-put-into-a-package/107277)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 19\
**Last updated:** [December 21, 2023, 12:23am UTC](https://discourse.julialang.org/t/broadcast-inside-of-mtkmodel-macro-causes-precompilation-failures-when-put-into-a-package/107277 "2023-12-21T00:23:05Z")

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While trying to implement a 3D version of the Mass-Spring model here in a package, I get the following error ERROR: LoadError: Evaluation into the closed module ModelingToolkit breaks incremental compilation because th…

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## [How to extend method used in package extension](https://discourse.julialang.org/t/how-to-extend-method-used-in-package-extension/107871)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 11\
**Last updated:** [December 20, 2023, 11:58pm UTC](https://discourse.julialang.org/t/how-to-extend-method-used-in-package-extension/107871 "2023-12-20T23:58:47Z")

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Hello, I am using a package which has plotting functionality defined in a package extension. It uses a function package\_function which is defined in the package module as function package\_function end and in the modul…

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## [Different api for scalar input in Enzyme.jl](https://discourse.julialang.org/t/different-api-for-scalar-input-in-enzyme-jl/107882)

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**Author:** [@jwalker](https://discourse.julialang.org/u/jwalker)\
**Replies:** 2\
**Last updated:** [December 20, 2023, 11:50pm UTC](https://discourse.julialang.org/t/different-api-for-scalar-input-in-enzyme-jl/107882 "2023-12-20T23:50:56Z")

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I’m puzzled by a difference in the API of Reverse mode with functions of scalar inputs versus those of other (e.g. vector inputs). It seems to be the case that for a scalar function of a scalar input, you must use Rever…

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## [Books for the Christmas break](https://discourse.julialang.org/t/books-for-the-christmas-break/107810)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 3\
**Last updated:** [December 20, 2023, 11:22pm UTC](https://discourse.julialang.org/t/books-for-the-christmas-break/107810 "2023-12-20T23:22:39Z")

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A thread for good books which might interest Julians. Let me start with this book, which shows the effects of rounding errors, mismatch of units and SQL errors Humble Pi: A Comedy of Maths Errors by Matt Parker | Goodre…

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## [JuMP @constraint macro modifies existing expression](https://discourse.julialang.org/t/jump-constraint-macro-modifies-existing-expression/107864)

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**Author:** [@Ethan-Russell](https://discourse.julialang.org/u/Ethan-Russell)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 9:03pm UTC](https://discourse.julialang.org/t/jump-constraint-macro-modifies-existing-expression/107864 "2023-12-20T21:03:10Z")

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I have encountered cases where JuMP will modify an expression if it is used in a constraint. This seems like undesirable behavior, as the expression could be used later thinking it is the same as the original. Here is …

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## [How can I return a live websocket connection in HTTP.jl?](https://discourse.julialang.org/t/how-can-i-return-a-live-websocket-connection-in-http-jl/66752)

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**Author:** [@PyDataBlog](https://discourse.julialang.org/u/PyDataBlog)\
**Replies:** 17\
**Last updated:** [December 20, 2023, 7:09pm UTC](https://discourse.julialang.org/t/how-can-i-return-a-live-websocket-connection-in-http-jl/66752 "2023-12-20T19:09:15Z")

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I have a live streaming connection opened via HTTP.jl’s Websocket with this snippet using HTTP using JSON3 HTTP.WebSockets.open("wss://ws.coincap.io/trades/binance") do ws while !eof(ws) println(readavailab…

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## [ForwardDiff.jl \\ Optiml.jl Newton Trust Region failing for unclear reason](https://discourse.julialang.org/t/forwarddiff-jl-optiml-jl-newton-trust-region-failing-for-unclear-reason/107799)

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**Author:** [@Gabriel\_Kreindler](https://discourse.julialang.org/u/Gabriel_Kreindler)\
**Replies:** 12\
**Last updated:** [December 20, 2023, 6:32pm UTC](https://discourse.julialang.org/t/forwarddiff-jl-optiml-jl-newton-trust-region-failing-for-unclear-reason/107799 "2023-12-20T18:32:14Z")

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I am trying to use Optim.jl’s NewtonTrustRegion with forward AD for computing the gradient and hessian. This fails for a reason that I don’t quite understand. I run optimize(fn\_closure, theta0, NewtonTrustRegion(), aut…

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## ["None Sym BasicSymbolic doesn't have a name" Problem when using NeuralPDE](https://discourse.julialang.org/t/none-sym-basicsymbolic-doesnt-have-a-name-problem-when-using-neuralpde/100348)

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**Author:** [@Ethan\_Tran](https://discourse.julialang.org/u/Ethan_Tran)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 6:25pm UTC](https://discourse.julialang.org/t/none-sym-basicsymbolic-doesnt-have-a-name-problem-when-using-neuralpde/100348 "2023-12-20T18:25:13Z")

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I try to use NeuralPDE to solve ODE problem, when I define the system with the separate variable u1(…) and u2(…) it run normally. (The code following) using NeuralPDE, Lux, ModelingToolkit, Optimization, OptimizationOpt…

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## [Where can I find certain matrix multiplication optimizations?](https://discourse.julialang.org/t/where-can-i-find-certain-matrix-multiplication-optimizations/107868)

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**Author:** [@meisel](https://discourse.julialang.org/u/meisel)\
**Replies:** 2\
**Last updated:** [December 20, 2023, 6:24pm UTC](https://discourse.julialang.org/t/where-can-i-find-certain-matrix-multiplication-optimizations/107868 "2023-12-20T18:24:38Z")

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Hi, there are a couple matrix multiplication optimizations that would have a big impact on the performance of my project. They are: Automatic coalescing of additions with multiplications, since \*gemm APIs typically all…

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## [Passing duplicate key in function through \`kwargs\` doesn't error](https://discourse.julialang.org/t/passing-duplicate-key-in-function-through-kwargs-doesnt-error/107870)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 6:09pm UTC](https://discourse.julialang.org/t/passing-duplicate-key-in-function-through-kwargs-doesnt-error/107870 "2023-12-20T18:09:46Z")

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If in Julia I try to do something like this, I’m rightly stopped by the program: julia\> f(; x, x) = x ERROR: syntax: function argument name not unique: "x" around REPL\[1\]:1 Stacktrace: \[1\] top-level scope @ REPL\[1\]:…

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## [How can I build an inner constructor accepting keywords arguments?](https://discourse.julialang.org/t/how-can-i-build-an-inner-constructor-accepting-keywords-arguments/107866)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 5\
**Last updated:** [December 20, 2023, 5:13pm UTC](https://discourse.julialang.org/t/how-can-i-build-an-inner-constructor-accepting-keywords-arguments/107866 "2023-12-20T17:13:07Z")

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I show my problem with a minimal example, say I have: julia\> @kwdef struct Foo x::Int = 3 y::Int Foo(m, x, y) = new(m\*x, m\*y) Foo(m; x, y) = Foo(m, x, y) end Foo I’d l…

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## [Differentiating random walk probability w.t.r. rate of jump](https://discourse.julialang.org/t/differentiating-random-walk-probability-w-t-r-rate-of-jump/107116)

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**Author:** [@aner-sanchez](https://discourse.julialang.org/u/aner-sanchez)\
**Replies:** 16\
**Last updated:** [December 20, 2023, 3:11pm UTC](https://discourse.julialang.org/t/differentiating-random-walk-probability-w-t-r-rate-of-jump/107116 "2023-12-20T15:11:24Z")

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Hello people! Perhaps this question should be in mathstackexchange, and sorry for the lousy formulation! but I feel this subject hits right in the heart of what I consider the Julia community. I’ve recently stumbled upon…

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## [MTK & \`@mtkmodel\` & \`@mtkbuild\`](https://discourse.julialang.org/t/mtk-mtkmodel-mtkbuild/104793)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 16\
**Last updated:** [December 20, 2023, 5:01pm UTC](https://discourse.julialang.org/t/mtk-mtkmodel-mtkbuild/104793 "2023-12-20T17:01:56Z")

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Great to see the latest update of the ModelingToolkit.jl documentation! The “new way” of doing things with @mtkmodel makes sense to me! There are a few things that I don’t understand in the transition from the “old” way…

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## [Implicit plot with plots](https://discourse.julialang.org/t/implicit-plot-with-plots/6585)

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**Author:** [@harven](https://discourse.julialang.org/u/harven)\
**Replies:** 17\
**Last updated:** [December 20, 2023, 4:29pm UTC](https://discourse.julialang.org/t/implicit-plot-with-plots/6585 "2023-12-20T16:29:28Z")

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How do I make an implicit plot with the plots package? pyplot has a contour function which admits a fourth argument to plot a single level line. But it does not seem to be implemented in plots.

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## [Read text file containing proper CSV data chunks](https://discourse.julialang.org/t/read-text-file-containing-proper-csv-data-chunks/107828)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 11\
**Last updated:** [December 20, 2023, 3:00pm UTC](https://discourse.julialang.org/t/read-text-file-containing-proper-csv-data-chunks/107828 "2023-12-20T15:00:55Z")

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I have a text file that contains comma-separated entries, and I am interested only in the rows that begin with the character A: file = """ C comment-1 B,9,5.5,20:30:33 A,2,1.5,20:31:15 C comment-2 A,0,0.5,22:57:00 C com…

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## [Testing a package extension?](https://discourse.julialang.org/t/testing-a-package-extension/107846)

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**Author:** [@johnomotani](https://discourse.julialang.org/u/johnomotani)\
**Replies:** 6\
**Last updated:** [December 20, 2023, 2:47pm UTC](https://discourse.julialang.org/t/testing-a-package-extension/107846 "2023-12-20T14:47:49Z")

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General question is: what is the recommended way to run CI tests on functionality provided in package extensions? One option would be I guess to make the tests require all the possible extension-triggering weak-dependen…

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## [Franklin.jl - how to link to a local PDF file?](https://discourse.julialang.org/t/franklin-jl-how-to-link-to-a-local-pdf-file/107860)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 2:46pm UTC](https://discourse.julialang.org/t/franklin-jl-how-to-link-to-a-local-pdf-file/107860 "2023-12-20T14:46:18Z")

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How can I add a PDF file as a downloadable link, in a webpage generated by Franklin.jl? I can store the PDF file in e.g. \_assets/.

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## [A jldoctest as a continuation of a previous jldoctest?](https://discourse.julialang.org/t/a-jldoctest-as-a-continuation-of-a-previous-jldoctest/107863)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 0\
**Last updated:** [December 20, 2023, 2:34pm UTC](https://discourse.julialang.org/t/a-jldoctest-as-a-continuation-of-a-previous-jldoctest/107863 "2023-12-20T14:34:24Z")

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Is it possible to use a jldoctest block as a continuation of a previous one? Something like: Create data with: \`\`\`jldoctest julia\> using MyPkg julia\> my\_data = MyPkg.data() Created data! \`\`\`~ And now, run function \`foo…

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## [Fill an instance of a function with a "." syntax (e.g. mod.fit(x, y))](https://discourse.julialang.org/t/fill-an-instance-of-a-function-with-a-syntax-e-g-mod-fit-x-y/107847)

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**Author:** [@matnbo](https://discourse.julialang.org/u/matnbo)\
**Replies:** 2\
**Last updated:** [December 20, 2023, 1:09pm UTC](https://discourse.julialang.org/t/fill-an-instance-of-a-function-with-a-syntax-e-g-mod-fit-x-y/107847 "2023-12-20T13:09:07Z")

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Dear all In the simplified example below, I have the following syntax where I build an instance of a given function “foo”. I named this instance “mod” (but this name can vary) and, in this instance, I fill the sub-obje…

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## [I'm new to Julia Programming Languages from an Asian country](https://discourse.julialang.org/t/im-new-to-julia-programming-languages-from-an-asian-country/107854)

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**Author:** [@giriprasathd](https://discourse.julialang.org/u/giriprasathd)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 1:29pm UTC](https://discourse.julialang.org/t/im-new-to-julia-programming-languages-from-an-asian-country/107854 "2023-12-20T13:29:20Z")

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Hello Julia Programmers, I need guidance to learning Julia programming languages, What is the job opportunities, where i can able to find jobs, any online courses or youtube videos.

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## [\[ANN\] List of Awesome Generative AI in/with/for Julia Language](https://discourse.julialang.org/t/ann-list-of-awesome-generative-ai-in-with-for-julia-language/105976)

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**Author:** [@svilupp](https://discourse.julialang.org/u/svilupp)\
**Replies:** 11\
**Last updated:** [December 20, 2023, 1:14pm UTC](https://discourse.julialang.org/t/ann-list-of-awesome-generative-ai-in-with-for-julia-language/105976 "2023-12-20T13:14:06Z")

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Generative AI and Julia, A Perfect Combination. Don’t you think? Generative AI is moving at the speed of light and it speaks Python. In my opinion, Julia is awesome. Wouldn’t it be a shame to miss out on the GenAI revo…

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## [Who is attending neurips?](https://discourse.julialang.org/t/who-is-attending-neurips/107343)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 0\
**Last updated:** [December 8, 2023, 8:25pm UTC](https://discourse.julialang.org/t/who-is-attending-neurips/107343 "2023-12-08T20:25:31Z")

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Dear friends of Julia language, I wonder who attend neurips? I am also curious how many papers used julia for neurips paper? I will arrive on Monday evening and we have a paper about optimizing heuristic functions for …

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## [Is Julia more suited as of now for classic ML rather than Gen Al, GNNs and evolutionary algorithms?](https://discourse.julialang.org/t/is-julia-more-suited-as-of-now-for-classic-ml-rather-than-gen-al-gnns-and-evolutionary-algorithms/107851)

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**Author:** [@Rajaram\_Venkataraman](https://discourse.julialang.org/u/Rajaram_Venkataraman)\
**Replies:** 1\
**Last updated:** [December 20, 2023, 12:41pm UTC](https://discourse.julialang.org/t/is-julia-more-suited-as-of-now-for-classic-ml-rather-than-gen-al-gnns-and-evolutionary-algorithms/107851 "2023-12-20T12:41:22Z")

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C++ and Python have packages for GNNs, generative AI, and genetic algorithms. It seems that Julia is currently more focused on classic ML and DNNs. Is that vorrect understanding? I am new to Julia.

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## [Gmsh generator under loop](https://discourse.julialang.org/t/gmsh-generator-under-loop/91726)

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**Author:** [@AniMondal](https://discourse.julialang.org/u/AniMondal)\
**Replies:** 3\
**Last updated:** [December 20, 2023, 11:48am UTC](https://discourse.julialang.org/t/gmsh-generator-under-loop/91726 "2023-12-20T11:48:09Z")

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Hello all, I am a begineer to Julia! I want to create three .vtk files. To do that, first I want to create three .msh files. The three .msh files should be generated under a for loop. To do so, I am running this Julia …

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