# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1151

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

**Page:** 1152

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## [Precompiling Plots LoadError Display not defined](https://discourse.julialang.org/t/precompiling-plots-loaderror-display-not-defined/74661)

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**Author:** [@fadil](https://discourse.julialang.org/u/fadil)\
**Replies:** 0\
**Last updated:** [January 15, 2022, 11:35am UTC](https://discourse.julialang.org/t/precompiling-plots-loaderror-display-not-defined/74661 "2022-01-15T11:35:21Z")

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I used Plots successfully. But now, when writing using Plots, I get the error: \[ Info: Precompiling Plots \[91a5bcdd-55d7-5caf-9e0b-520d859cae80\] ERROR: LoadError: UndefVarError: Display not defined What to do?

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## [Create histogram with missing values](https://discourse.julialang.org/t/create-histogram-with-missing-values/74617)

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**Author:** [@Norbert-droid](https://discourse.julialang.org/u/Norbert-droid)\
**Replies:** 6\
**Last updated:** [January 15, 2022, 8:20am UTC](https://discourse.julialang.org/t/create-histogram-with-missing-values/74617 "2022-01-15T08:20:53Z")

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I want to make a histogram with the data in a column of a data frame; the column has a lot of missing values. I don’t want to drop the missing values in the data frame or create a new array without missing values. How do…

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## [Wrapping a Complicated, Multi-Threaded C/C++ Library](https://discourse.julialang.org/t/wrapping-a-complicated-multi-threaded-c-c-library/65401)

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**Author:** [@colinxs](https://discourse.julialang.org/u/colinxs)\
**Replies:** 0\
**Last updated:** [July 27, 2021, 9:31pm UTC](https://discourse.julialang.org/t/wrapping-a-complicated-multi-threaded-c-c-library/65401 "2021-07-27T21:31:51Z")

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I’m attempting to wrap a somewhat complicated C++ library using CxxWrap and am running into issues when it comes to blocking and multi-threaded C++ code. Here’s an abbreviated example of the problem: # Functions/objects…

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## [How to efficiently build AD-compatible matrices line by line](https://discourse.julialang.org/t/how-to-efficiently-build-ad-compatible-matrices-line-by-line/74632)

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**Author:** [@GlenHenshaw](https://discourse.julialang.org/u/GlenHenshaw)\
**Replies:** 17\
**Last updated:** [January 15, 2022, 3:46am UTC](https://discourse.julialang.org/t/how-to-efficiently-build-ad-compatible-matrices-line-by-line/74632 "2022-01-15T03:46:01Z")

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I find myself frequently needing a construct like the following: a = Array{Float32}(undef, 100, 5) for i=1:100 a\[i, :\] = \<a vector\> end which works fine in plain Julia, and is highly efficient, but gives Flux fits …

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## [Why is BitArray so slow?](https://discourse.julialang.org/t/why-is-bitarray-so-slow/14383)

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**Author:** [@mbeach42](https://discourse.julialang.org/u/mbeach42)\
**Replies:** 28\
**Last updated:** [January 14, 2022, 10:43pm UTC](https://discourse.julialang.org/t/why-is-bitarray-so-slow/14383 "2022-01-14T22:43:46Z")

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I was playing around with flipping numbers of an array, and I was surprised that doing so with BitArrays is much slower. I think the code below is pretty clear, using BenchmarkTools using Random a = rand(-1:2:1, 26, 11…

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## [Julia Thread Affinity not persistent when calling MKL function](https://discourse.julialang.org/t/julia-thread-affinity-not-persistent-when-calling-mkl-function/74560)

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**Author:** [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Replies:** 2\
**Last updated:** [January 14, 2022, 8:10pm UTC](https://discourse.julialang.org/t/julia-thread-affinity-not-persistent-when-calling-mkl-function/74560 "2022-01-14T20:10:45Z")

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I observe a subtle issue where the pinning of Julia threads to specific cores is spoiled massively by running a seemingly harmless computation. By spoiled I mean that after running the computation all threads are pinned …

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## [3D object rotation in Makie doesn't seem to work well on wide aspect ratio monitors](https://discourse.julialang.org/t/3d-object-rotation-in-makie-doesnt-seem-to-work-well-on-wide-aspect-ratio-monitors/74582)

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**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 2\
**Last updated:** [January 14, 2022, 7:58pm UTC](https://discourse.julialang.org/t/3d-object-rotation-in-makie-doesnt-seem-to-work-well-on-wide-aspect-ratio-monitors/74582 "2022-01-14T19:58:16Z")

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On my 21:9 aspect ratio monitor the rotation increment angle is so large that the teeniest movement of the mouse makes the object rotate by such a large angle that it is impossible to orient objects the way you want them…

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## [Why am I getting OutOfMemoryError() and how do I avoid it?](https://discourse.julialang.org/t/why-am-i-getting-outofmemoryerror-and-how-do-i-avoid-it/74639)

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**Author:** [@Soldalma](https://discourse.julialang.org/u/Soldalma)\
**Replies:** 4\
**Last updated:** [January 14, 2022, 7:26pm UTC](https://discourse.julialang.org/t/why-am-i-getting-outofmemoryerror-and-how-do-i-avoid-it/74639 "2022-01-14T19:26:14Z")

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I am trying to generate combinations of integers in the range from 1 to 12. Using 8 as an argument for the function below I get an OutOfMemory() error. The function works as expected for N \< 8. My PC has 32GB of memory o…

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## [Data Science lessons: Making "10 - Neural Networks" run on GPU?](https://discourse.julialang.org/t/data-science-lessons-making-10-neural-networks-run-on-gpu/74592)

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**Author:** [@drscotthawley](https://discourse.julialang.org/u/drscotthawley)\
**Replies:** 4\
**Last updated:** [January 14, 2022, 5:35pm UTC](https://discourse.julialang.org/t/data-science-lessons-making-10-neural-networks-run-on-gpu/74592 "2022-01-14T17:35:42Z")

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Hi, I’ve been doing Dr. Nassar’s @nassarhuda’s excellent Data Science tutorial series on Julia Academy and just finished lesson 10 on Neural Nets (Neural Nets | JuliaAcademy). I’m now trying to edit the notebook from th…

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## [Am I going about solving this PDE system the right way...?](https://discourse.julialang.org/t/am-i-going-about-solving-this-pde-system-the-right-way/74621)

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**Author:** [@Thaegy](https://discourse.julialang.org/u/Thaegy)\
**Replies:** 8\
**Last updated:** [January 14, 2022, 5:10pm UTC](https://discourse.julialang.org/t/am-i-going-about-solving-this-pde-system-the-right-way/74621 "2022-01-14T17:10:00Z")

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I have been transitioning my MATLAB code to Julia and managed to get working a sort of analogue to my MATLAB code. My PDE system has 2 coupled (1+1)D nonlinear PDEs: -\\mathrm{i}\\left(\\frac{\\partial \\psi}{\\partial X}\\r…

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## [Correlation between categorial variables](https://discourse.julialang.org/t/correlation-between-categorial-variables/74411)

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**Author:** [@iskyd](https://discourse.julialang.org/u/iskyd)\
**Replies:** 3\
**Last updated:** [January 14, 2022, 4:56pm UTC](https://discourse.julialang.org/t/correlation-between-categorial-variables/74411 "2022-01-14T16:56:10Z")

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I created a DataFrame from a CSV simply doing df = DataFrame(CSV.File(“input.csv”)) Using describe(df) I noticed that I have both Int variables and String variables with eltype String7, String3 and so on. To calculate …

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## [What is grounded type in Julia?](https://discourse.julialang.org/t/what-is-grounded-type-in-julia/74579)

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**Author:** [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Replies:** 7\
**Last updated:** [January 14, 2022, 4:19pm UTC](https://discourse.julialang.org/t/what-is-grounded-type-in-julia/74579 "2022-01-14T16:19:56Z")

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In prof. Jan Vitek JuliaCon 2021 keynote, he discussed type stability and grounded type (starting at 42:30). Short definitions given at this talk are as follow. Type is stable if we have clear relation between I/O types…

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## [Flailing on evaluating batches as matrices of features](https://discourse.julialang.org/t/flailing-on-evaluating-batches-as-matrices-of-features/74446)

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**Author:** [@GlenHenshaw](https://discourse.julialang.org/u/GlenHenshaw)\
**Replies:** 6\
**Last updated:** [January 14, 2022, 4:13pm UTC](https://discourse.julialang.org/t/flailing-on-evaluating-batches-as-matrices-of-features/74446 "2022-01-14T16:13:48Z")

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This is my first significant Flux program, be gentle :wink: I have a model m. It takes two vectors as input (via a Parallel(vcat...) layer), the first of which is a vector of floats and the second is a one-hot. I can ge…

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## [Incorrect volume estimate in Qhull.jl](https://discourse.julialang.org/t/incorrect-volume-estimate-in-qhull-jl/74622)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 11\
**Last updated:** [January 14, 2022, 3:56pm UTC](https://discourse.julialang.org/t/incorrect-volume-estimate-in-qhull-jl/74622 "2022-01-14T15:56:32Z")

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I am trying to use QHull.jl to estimate the volume of points in high dimensional space. Unfortunately, some of the results from simple 2D examples seem to be in correct. Here is a MWE: using Plots, QHull, Random Rando…

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## [Is Jeff Bezanson's 2014 "Introduction to Julia Internals" relevant in 2021 onward?](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255)

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**Author:** [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Replies:** 3\
**Last updated:** [December 20, 2021, 11:20pm UTC](https://discourse.julialang.org/t/is-jeff-bezansons-2014-introduction-to-julia-internals-relevant-in-2021-onward/73255 "2021-12-20T23:20:49Z")

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I’m kind of fan of Jeff Bezanson’s talks and recently I watched his talk from first JuliaCon 2014 titled Introduction to Julia Internals. I found there many information that were totally new to me about internal working …

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## [SQLite.jl NOT NULL constraint failed](https://discourse.julialang.org/t/sqlite-jl-not-null-constraint-failed/74628)

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**Author:** [@Jeremy](https://discourse.julialang.org/u/Jeremy)\
**Replies:** 0\
**Last updated:** [January 14, 2022, 2:52pm UTC](https://discourse.julialang.org/t/sqlite-jl-not-null-constraint-failed/74628 "2022-01-14T14:52:04Z")

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Since updating Julia from v1.6.2 (SQLite v1.2.0) to v1.7.1 (SQLite v 1.3.0) I get an error while trying to add data to an existing table in my database. julia\> dataBiomet |\> SQLite.load!(db,"Biomet") ERROR: SQLiteExcept…

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## [Best practice to support multiple implementations](https://discourse.julialang.org/t/best-practice-to-support-multiple-implementations/74240)

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**Author:** [@roh\_codeur](https://discourse.julialang.org/u/roh_codeur)\
**Replies:** 16\
**Last updated:** [January 14, 2022, 1:34pm UTC](https://discourse.julialang.org/t/best-practice-to-support-multiple-implementations/74240 "2022-01-14T13:34:57Z")

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Hi I am a newbie to the language, coming from an OOP background. I have a method as below: function run(downloader) downloader.download() end the downloader can have several implementations, for instance, could…

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## [Benders Decomposition with callback](https://discourse.julialang.org/t/benders-decomposition-with-callback/74620)

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**Author:** [@ahmad88](https://discourse.julialang.org/u/ahmad88)\
**Replies:** 0\
**Last updated:** [January 14, 2022, 1:28pm UTC](https://discourse.julialang.org/t/benders-decomposition-with-callback/74620 "2022-01-14T13:28:53Z")

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I am trying to implement Benders Decomposition for a graph problem, I have a master problem and subproblem and in each iteration, I have to solve the master problem change the RHS of the subproblem constraint and solve t…

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## [Using Turing with ad-hoc likelihood](https://discourse.julialang.org/t/using-turing-with-ad-hoc-likelihood/74601)

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**Author:** [@Marco\_Lombardi](https://discourse.julialang.org/u/Marco_Lombardi)\
**Replies:** 1\
**Last updated:** [January 14, 2022, 12:57pm UTC](https://discourse.julialang.org/t/using-turing-with-ad-hoc-likelihood/74601 "2022-01-14T12:57:04Z")

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I am new to probabilistic programming an I would like to use Turing to perform statistical inference for a relatively complex physical problem, involving a specific model and a set of observations. The model has a few nu…

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## [Efficient conditional in-place assignment for arrays?](https://discourse.julialang.org/t/efficient-conditional-in-place-assignment-for-arrays/74593)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 7\
**Last updated:** [January 14, 2022, 12:26pm UTC](https://discourse.julialang.org/t/efficient-conditional-in-place-assignment-for-arrays/74593 "2022-01-14T12:26:29Z")

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Is there any way to the get the efficient assignment of f1 with the nicer syntax of f2? Something like a view or conditional SubArray? julia\> function f1!(xs) for i in eachindex(xs) if xs\[i\] \< 0.5 …

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## [Dictionary Initialization and Usage](https://discourse.julialang.org/t/dictionary-initialization-and-usage/74609)

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**Author:** [@Rajat\_Chaudhari](https://discourse.julialang.org/u/Rajat_Chaudhari)\
**Replies:** 4\
**Last updated:** [January 14, 2022, 12:23pm UTC](https://discourse.julialang.org/t/dictionary-initialization-and-usage/74609 "2022-01-14T12:23:09Z")

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I started with Julia today and was experimenting with Dictionary feature. The following is the code I wrote when I faced the error. Could anyone point out as to why such error is occuring and why such usage is wrong? …

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## [Structural code review Tutor (paid)](https://discourse.julialang.org/t/structural-code-review-tutor-paid/74598)

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**Author:** [@AlexanderChen](https://discourse.julialang.org/u/AlexanderChen)\
**Replies:** 1\
**Last updated:** [January 14, 2022, 11:55am UTC](https://discourse.julialang.org/t/structural-code-review-tutor-paid/74598 "2022-01-14T11:55:26Z")

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hi, i am learning julia now for a couple of years on the side (BI consultant) but I want to take it to a deeper level this year. I am looking for a Tutor (or a group of tutors) with which I can agree on certain projects…

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## [ROS C++ full package tutorial](https://discourse.julialang.org/t/ros-c-full-package-tutorial/74595)

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**Author:** [@kobied](https://discourse.julialang.org/u/kobied)\
**Replies:** 0\
**Last updated:** [January 14, 2022, 6:37am UTC](https://discourse.julialang.org/t/ros-c-full-package-tutorial/74595 "2022-01-14T06:37:56Z")

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Hi, i have been looking for a full tutorial on how to build a ros cpp package using ‘ROS.jl’ but couldn’t find one. Any one knows were i can find such tutorial?

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## [Reproducible simulations](https://discourse.julialang.org/t/reproducible-simulations/74589)

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**Author:** [@stephenll](https://discourse.julialang.org/u/stephenll)\
**Replies:** 3\
**Last updated:** [January 14, 2022, 6:09am UTC](https://discourse.julialang.org/t/reproducible-simulations/74589 "2022-01-14T06:09:41Z")

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At my job it is very important to have our algorithms be as close to reproducible as possible on different systems, no matter the number of cores. Even though, in my mind, it shouldn’t matter, the powers that be want th…

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## [Best practice for script with ARGS that can also be run with \`include\`](https://discourse.julialang.org/t/best-practice-for-script-with-args-that-can-also-be-run-with-include/74435)

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**Author:** [@goerz](https://discourse.julialang.org/u/goerz)\
**Replies:** 3\
**Last updated:** [January 14, 2022, 4:11am UTC](https://discourse.julialang.org/t/best-practice-for-script-with-args-that-can-also-be-run-with-include/74435 "2022-01-14T04:11:02Z")

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I’m trying to figure out a good pattern for writing scripts that take command line arguments, and that are easy to run both from the shell (julia script.jl), and from inside the REPL/another Julia script (via include). T…

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## [Why is \`TaskLocalRNG\` faster than \`Xoshiro\` with multiple threads?](https://discourse.julialang.org/t/why-is-tasklocalrng-faster-than-xoshiro-with-multiple-threads/74577)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 7\
**Last updated:** [January 14, 2022, 3:58am UTC](https://discourse.julialang.org/t/why-is-tasklocalrng-faster-than-xoshiro-with-multiple-threads/74577 "2022-01-14T03:58:52Z")

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I was a bit confused by the docs: In a multi-threaded program, you should generally use different RNG objects from different threads or tasks in order to be thread-safe. However, the default RNG is thread-safe as of Ju…

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## [Downloaded artifact: Enzyme took me forever and install failed](https://discourse.julialang.org/t/downloaded-artifact-enzyme-took-me-forever-and-install-failed/74585)

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**Author:** [@frydaydeep](https://discourse.julialang.org/u/frydaydeep)\
**Replies:** 1\
**Last updated:** [January 14, 2022, 2:00am UTC](https://discourse.julialang.org/t/downloaded-artifact-enzyme-took-me-forever-and-install-failed/74585 "2022-01-14T02:00:53Z")

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I met this problem when adding another package as well, what is artifact: Enzyme? google don’t know \]add OffsetArrays Resolving package versions… Downloaded artifact: Enzyme Downloaded artifact: Enzyme ERROR: Unab…

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## [Pluto.jl, WGLMakie, JSServe behind firewall](https://discourse.julialang.org/t/pluto-jl-wglmakie-jsserve-behind-firewall/73111)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 2\
**Last updated:** [January 14, 2022, 1:18am UTC](https://discourse.julialang.org/t/pluto-jl-wglmakie-jsserve-behind-firewall/73111 "2022-01-14T01:18:25Z")

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I am trying to use a Pluto notebook with a Makie backend that works with Pluto Notebook for 3D graphics. In an effort to use WGLMakie, I tried: begin using JSServe Page() end I get blocked by the corporate fir…

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## [State of Julia grammar for tree-sitter](https://discourse.julialang.org/t/state-of-julia-grammar-for-tree-sitter/74573)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 5\
**Last updated:** [January 14, 2022, 1:00am UTC](https://discourse.julialang.org/t/state-of-julia-grammar-for-tree-sitter/74573 "2022-01-14T01:00:17Z")

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Hi! I saw that Julia has an initial implementation of grammar for tree-sitter. However, the development seems stalled: https://github.com/tree-sitter/tree-sitter-julia I tried, but it seems to lack many things. It fai…

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## [Storing Strings using For Loops](https://discourse.julialang.org/t/storing-strings-using-for-loops/74578)

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**Author:** [@slumpito](https://discourse.julialang.org/u/slumpito)\
**Replies:** 6\
**Last updated:** [January 13, 2022, 11:32pm UTC](https://discourse.julialang.org/t/storing-strings-using-for-loops/74578 "2022-01-13T23:32:26Z")

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Hi, I am absolutely novice at this in general. My background is in mechanical engineering so only have had self-learning and an intro to C course. I am parsing a file of text that I get from my simulations and I am havin…

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