# Latest

**URL:** https://discourse.julialang.org/latest.md?page=936

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

**Page:** 937

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## [Fast(er) priority queues?](https://discourse.julialang.org/t/fast-er-priority-queues/81269)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 20\
**Last updated:** [September 1, 2022, 6:47pm UTC](https://discourse.julialang.org/t/fast-er-priority-queues/81269 "2022-09-01T18:47:11Z")

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Hi there! Recently I wanted to accelerate Dijkstra’s algorithm, and I ended up implementing a really dumb priority queue based on two sorted vectors. Surprisingly, in some settings, it significantly speeds up the algori…

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## [REPL in Vim](https://discourse.julialang.org/t/repl-in-vim/86649)

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**Author:** [@pedro.rafae](https://discourse.julialang.org/u/pedro.rafae)\
**Replies:** 2\
**Last updated:** [September 1, 2022, 6:43pm UTC](https://discourse.julialang.org/t/repl-in-vim/86649 "2022-09-01T18:43:15Z")

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Dear friends, what’s the best way to invoke Julia’s REPL for someone using the Vim editor? I’m using the Julia plugin for Vim, but I always have to be compiling the Julia code. I would like to know if there is any inter…

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## [Trying to use map function in Threads](https://discourse.julialang.org/t/trying-to-use-map-function-in-threads/86603)

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**Author:** [@jmurga](https://discourse.julialang.org/u/jmurga)\
**Replies:** 6\
**Last updated:** [September 1, 2022, 4:30pm UTC](https://discourse.julialang.org/t/trying-to-use-map-function-in-threads/86603 "2022-09-01T16:30:14Z")

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Hi guys, I am trying to parallelize a computation using Threads instead of processes. I have tested my functions several times using Distributed package, and everything is working as expected with pmap(). I was trying …

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## [How to utilize "MKLSparse.jl"?](https://discourse.julialang.org/t/how-to-utilize-mklsparse-jl/85263)

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**Author:** [@Amro](https://discourse.julialang.org/u/Amro)\
**Replies:** 14\
**Last updated:** [September 1, 2022, 3:56pm UTC](https://discourse.julialang.org/t/how-to-utilize-mklsparse-jl/85263 "2022-09-01T15:56:08Z")

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I have some sparse matrices and I thought using “MKLSparse.jl” could faster the execution, but it did not. However, in the documentation, there is this note The integer type that should be used in order for MKL to be …

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## [Error when using StatsPlots](https://discourse.julialang.org/t/error-when-using-statsplots/86646)

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**Author:** [@Abdou](https://discourse.julialang.org/u/Abdou)\
**Replies:** 0\
**Last updated:** [September 1, 2022, 3:38pm UTC](https://discourse.julialang.org/t/error-when-using-statsplots/86646 "2022-09-01T15:38:38Z")

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I’ve just installed Julia 1.8 and added StatPlots to my packages but when I try to use this package I get this errors ERROR: LoadError: InitError: could not load library “C:\\Users\\username.julia\\artifacts\\79e8b1aff46d44…

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## [Save a figure with a specific size with a subplot of a specific size in Plots.jl (with PGFPlotsX backend)](https://discourse.julialang.org/t/save-a-figure-with-a-specific-size-with-a-subplot-of-a-specific-size-in-plots-jl-with-pgfplotsx-backend/86614)

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**Author:** [@JonasWickman](https://discourse.julialang.org/u/JonasWickman)\
**Replies:** 2\
**Last updated:** [September 1, 2022, 3:02pm UTC](https://discourse.julialang.org/t/save-a-figure-with-a-specific-size-with-a-subplot-of-a-specific-size-in-plots-jl-with-pgfplotsx-backend/86614 "2022-09-01T15:02:54Z")

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In PyPlot, I can output a figure with a specific size containing an axis in the figure with a specific size using the code: using PyPlot fig\_width = 4.0 fig\_height = 3.0 fig = figure( figsize = (fig\_width, fig\_height) )…

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## [How to read specific columns of a csv file](https://discourse.julialang.org/t/how-to-read-specific-columns-of-a-csv-file/86644)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 1\
**Last updated:** [September 1, 2022, 2:42pm UTC](https://discourse.julialang.org/t/how-to-read-specific-columns-of-a-csv-file/86644 "2022-09-01T14:42:22Z")

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I am trying to read the first column of “test.csv” file using CSV.jl. I don’t understand why this doesn’t work: test.csv is: a;b;c 1;2;3 4;5;6 9;8;7 using CSV y\_train = CSV.File("test.csv"; select=\[:, 1\]) Is it po…

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## [Is cis returning correct results?](https://discourse.julialang.org/t/is-cis-returning-correct-results/86641)

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**Author:** [@nandoconde](https://discourse.julialang.org/u/nandoconde)\
**Replies:** 3\
**Last updated:** [September 1, 2022, 2:03pm UTC](https://discourse.julialang.org/t/is-cis-returning-correct-results/86641 "2022-09-01T14:03:44Z")

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Maybe I am doing something wrong in my reasoning, but analytically cis(x\*y) == cis(x)^y In code: julia\> # Using Float julia\> cis(5e7 \* 2.0) -0.3633850893556905 + 0.931639027109726im julia\> cis(5e7) ^ 2.0 -0.3633850893…

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## [Plot The Squeeze Theorem Correctly](https://discourse.julialang.org/t/plot-the-squeeze-theorem-correctly/86585)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 5\
**Last updated:** [September 1, 2022, 1:20pm UTC](https://discourse.julialang.org/t/plot-the-squeeze-theorem-correctly/86585 "2022-09-01T13:20:47Z")

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Hi all, I am trying to plot something to follow the Squeeze Theorem. It turns out to become funny. using Plots, LaTeXStrings pyplot(fmt=:svg) function pitick(start, stop, denom; mode=:text) a = Int(cld(start, π/de…

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## [Package on gitlab not github](https://discourse.julialang.org/t/package-on-gitlab-not-github/86637)

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**Author:** [@Barvid](https://discourse.julialang.org/u/Barvid)\
**Replies:** 10\
**Last updated:** [September 1, 2022, 12:48pm UTC](https://discourse.julialang.org/t/package-on-gitlab-not-github/86637 "2022-09-01T12:48:08Z")

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Hello I was ask to make some julia code in my company. The main page 5. Creating Packages · Pkg.jl tell me to use User Guide · PkgTemplates.jl . All need githup. We are not allowed to use githup in my company. My comp…

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## [Container of mutable structs without 100x slowdown?](https://discourse.julialang.org/t/container-of-mutable-structs-without-100x-slowdown/86629)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 7\
**Last updated:** [September 1, 2022, 12:03pm UTC](https://discourse.julialang.org/t/container-of-mutable-structs-without-100x-slowdown/86629 "2022-09-01T12:03:08Z")

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It seems like when mutable structs are stored in any kind of container, Julia is unable to optimize them onto the stack or even to a packed buffer on the heap. It always allocates new memory on the heap for each individ…

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## [Issues with PSO within Optim.jl](https://discourse.julialang.org/t/issues-with-pso-within-optim-jl/86638)

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**Author:** [@NTmuir](https://discourse.julialang.org/u/NTmuir)\
**Replies:** 0\
**Last updated:** [September 1, 2022, 11:56am UTC](https://discourse.julialang.org/t/issues-with-pso-within-optim-jl/86638 "2022-09-01T11:56:17Z")

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Hi there, I am fairly new to Julia and I am struggling to get a PSO to work within Optim.jl, I am using PETLION which is physical based battery simulation tool to get voltage data while changing a single physical parame…

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## [\[ANN\] JuliaPhysics organization & logo contest](https://discourse.julialang.org/t/ann-juliaphysics-organization-logo-contest/3970)

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**Author:** [@giordano](https://discourse.julialang.org/u/giordano)\
**Replies:** 60\
**Last updated:** [September 1, 2022, 11:42am UTC](https://discourse.julialang.org/t/ann-juliaphysics-organization-logo-contest/3970 "2022-09-01T11:42:43Z")

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I’ve just registered a new Julia organization at JuliaPhysics · GitHub with the goal of gathering generic packages that can be useful in physics. For example, I’m considering the possibility of moving Measurements.jl th…

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## [What makes a function interruptible with ctrl+c?](https://discourse.julialang.org/t/what-makes-a-function-interruptible-with-ctrl-c/86625)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 5\
**Last updated:** [September 1, 2022, 10:50am UTC](https://discourse.julialang.org/t/what-makes-a-function-interruptible-with-ctrl-c/86625 "2022-09-01T10:50:26Z")

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Ctrl+c fails to interrupt many functions. What makes a function interruptible?

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## [Good solver for nonlinear diffusion PDE with source?](https://discourse.julialang.org/t/good-solver-for-nonlinear-diffusion-pde-with-source/86587)

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**Author:** [@JordiBolibar](https://discourse.julialang.org/u/JordiBolibar)\
**Replies:** 1\
**Last updated:** [August 31, 2022, 1:45pm UTC](https://discourse.julialang.org/t/good-solver-for-nonlinear-diffusion-pde-with-source/86587 "2022-08-31T13:45:37Z")

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With @facusapienza we’re trying to find a good solver to solve a 2D nonlinear ice flow PDE with mass addition and subtraction (i.e. heat equation with source). We are encountering a big difference in solving it with and …

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## [Package for lazy hcat/vcat of a large number of vectors](https://discourse.julialang.org/t/package-for-lazy-hcat-vcat-of-a-large-number-of-vectors/86590)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 9\
**Last updated:** [September 1, 2022, 10:11am UTC](https://discourse.julialang.org/t/package-for-lazy-hcat-vcat-of-a-large-number-of-vectors/86590 "2022-09-01T10:11:13Z")

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I am looking for the lazy equivalent of v = \[rand(500) for \_ in 1:5000\]; mapreduce(permutedims, vcat, v) where both dimensions may be large (up 10⁵). This is trivial to code up but I want to avoid duplication. Is ther…

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## [Julia vs (R/STATA/Matlab/SAS/Python) for common data analysis tasks (2022 edition)](https://discourse.julialang.org/t/julia-vs-r-stata-matlab-sas-python-for-common-data-analysis-tasks-2022-edition/85801)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 6\
**Last updated:** [September 1, 2022, 10:01am UTC](https://discourse.julialang.org/t/julia-vs-r-stata-matlab-sas-python-for-common-data-analysis-tasks-2022-edition/85801 "2022-09-01T10:01:22Z")

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From a previous discussion So I’m starting this thread with the idea that people could come here with some example data analysis problems and Julia users can reproduce something like them here to give people a sense o…

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## [How to select a subgraph in Graph.jl Package](https://discourse.julialang.org/t/how-to-select-a-subgraph-in-graph-jl-package/86631)

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**Author:** [@A\_Green\_Leave](https://discourse.julialang.org/u/A_Green_Leave)\
**Replies:** 1\
**Last updated:** [September 1, 2022, 8:50am UTC](https://discourse.julialang.org/t/how-to-select-a-subgraph-in-graph-jl-package/86631 "2022-09-01T08:50:29Z")

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Hi, I’m working with Graph and SimpleWeightedGraphs Packages and was wondering if they allow to extract/select a subgraph and work with it too? I mean having a subgraph knowing its edges and nodes. I’d like to work w…

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## [How to export modules / packages locally?](https://discourse.julialang.org/t/how-to-export-modules-packages-locally/86606)

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**Author:** [@hamburger](https://discourse.julialang.org/u/hamburger)\
**Replies:** 10\
**Last updated:** [September 1, 2022, 8:01am UTC](https://discourse.julialang.org/t/how-to-export-modules-packages-locally/86606 "2022-09-01T08:01:50Z")

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How to export modules / packages locally? Hello! I’ve been looking unsuccessfully at how to develop multiple distinct modules locally. My project has three parts: Two modules: TextManipulation, AstroPhysics One Julia…

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## [Add column and column names of variable lags to dataframe](https://discourse.julialang.org/t/add-column-and-column-names-of-variable-lags-to-dataframe/86571)

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**Author:** [@Longblackcoffee](https://discourse.julialang.org/u/Longblackcoffee)\
**Replies:** 5\
**Last updated:** [September 1, 2022, 6:28am UTC](https://discourse.julialang.org/t/add-column-and-column-names-of-variable-lags-to-dataframe/86571 "2022-09-01T06:28:51Z")

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Hi everyone, I have a dataset and I want to add a new column for every lag, with the column name being variable\_(lag number). So for example, using DataFrames using ShiftedArrays test = DataFrame(a=1:10, b=11:20) I w…

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## [Maximum with \`by\` keyword](https://discourse.julialang.org/t/maximum-with-by-keyword/86627)

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**Author:** [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)\
**Replies:** 1\
**Last updated:** [September 1, 2022, 6:53am UTC](https://discourse.julialang.org/t/maximum-with-by-keyword/86627 "2022-09-01T06:53:06Z")

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I have a vector of Tuples v for which I want to find the maximum based on, say, the first element of the Tuple. sort has the by keyword: to sort the vector I would do sort(v; by=x-\>x\[1\]). What is the equivalent way for m…

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## [Julia 1.8.1 testing period](https://discourse.julialang.org/t/julia-1-8-1-testing-period/86626)

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**Author:** [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Replies:** 0\
**Last updated:** [September 1, 2022, 6:10am UTC](https://discourse.julialang.org/t/julia-1-8-1-testing-period/86626 "2022-09-01T06:10:40Z")

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The release-1.8 branch on the Julia repository now contains the set of commits we’re planning to tag as v1.8.1, the first patch release in the 1.8 series. The list of commits included since v1.8.0 is available here . As …

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## [Constructors for \`\<:Function\` types when possible, like in C++](https://discourse.julialang.org/t/constructors-for-function-types-when-possible-like-in-c/86611)

<div class="topic-metadata">

**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 7\
**Last updated:** [September 1, 2022, 2:13am UTC](https://discourse.julialang.org/t/constructors-for-function-types-when-possible-like-in-c/86611 "2022-09-01T02:13:32Z")

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I was thinking about how C++20 added support for default constructors for stateless (with no captures) lambdas, meaning that nowadays all function object families may be default-constructible in C++. Then I realized tha…

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## [Directly modify compiled method without recompilation](https://discourse.julialang.org/t/directly-modify-compiled-method-without-recompilation/86564)

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**Author:** [@FireCrumb](https://discourse.julialang.org/u/FireCrumb)\
**Replies:** 25\
**Last updated:** [August 31, 2022, 9:05pm UTC](https://discourse.julialang.org/t/directly-modify-compiled-method-without-recompilation/86564 "2022-08-31T21:05:45Z")

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Question – how can I evaluate an expression into a method, compile it, and then directly manipulate the compiled version (lower than AST) to create another slightly modified method faster than re-compilation? I need to …

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## [Determinant of a symbolic matrix](https://discourse.julialang.org/t/determinant-of-a-symbolic-matrix/85587)

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**Author:** [@qwerty](https://discourse.julialang.org/u/qwerty)\
**Replies:** 4\
**Last updated:** [September 1, 2022, 12:33am UTC](https://discourse.julialang.org/t/determinant-of-a-symbolic-matrix/85587 "2022-09-01T00:33:39Z")

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With Symbolics.jl how do I get the determinant of a symbolic matrix? I tried this: @variables a\[1:2, 1:2\] det(a) The only thing I can get is: Symbolics.\_det(a, true)

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## [Neither Parquet.jl nor Parquet2.jl can read my .parquet file](https://discourse.julialang.org/t/neither-parquet-jl-nor-parquet2-jl-can-read-my-parquet-file/86610)

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**Author:** [@adienes](https://discourse.julialang.org/u/adienes)\
**Replies:** 7\
**Last updated:** [August 31, 2022, 10:45pm UTC](https://discourse.julialang.org/t/neither-parquet-jl-nor-parquet2-jl-can-read-my-parquet-file/86610 "2022-08-31T22:45:29Z")

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I am trying to load a parquet file (about 1Gb) on Julia 1.8, and neither Parquet.read\_parquet nor Parquet2.readfile are able to open it. The former just hangs forever until I kill it, and the latter gives me a very long …

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## [Is it possible to precompile a function in Julia?](https://discourse.julialang.org/t/is-it-possible-to-precompile-a-function-in-julia/86578)

<div class="topic-metadata">

**Author:** [@valperez](https://discourse.julialang.org/u/valperez)\
**Replies:** 2\
**Last updated:** [August 31, 2022, 10:02pm UTC](https://discourse.julialang.org/t/is-it-possible-to-precompile-a-function-in-julia/86578 "2022-08-31T22:02:05Z")

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Hi there, I’m trying to make my Julia code as fast as possible and a friend of mine recommended using precompile. I have read about it but I’m not sure how to proceed, do I precompile the package I’m using o the functio…

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## [Retarded Gravitation problem (delay differential equations with variable delay)](https://discourse.julialang.org/t/retarded-gravitation-problem-delay-differential-equations-with-variable-delay/86479)

<div class="topic-metadata">

**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 16\
**Last updated:** [August 31, 2022, 6:45pm UTC](https://discourse.julialang.org/t/retarded-gravitation-problem-delay-differential-equations-with-variable-delay/86479 "2022-08-31T18:45:05Z")

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A friend and I were discussing gravity including retarded potentials from the finite speed of light. This is not general relativity but more like special relativity applied to gravity. We had the idea to simulate some “…

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## [@pyimport numpy throwing an error when precompiling a module](https://discourse.julialang.org/t/pyimport-numpy-throwing-an-error-when-precompiling-a-module/86599)

<div class="topic-metadata">

**Author:** [@jcrismer](https://discourse.julialang.org/u/jcrismer)\
**Replies:** 5\
**Last updated:** [August 31, 2022, 6:43pm UTC](https://discourse.julialang.org/t/pyimport-numpy-throwing-an-error-when-precompiling-a-module/86599 "2022-08-31T18:43:49Z")

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Hi everyone ! I am running on a Mac (with M1 chip) and I am quite new to Julia. I am currently modifying an existing Julia package. I want to call/write some python code requiring importing numpy. However when precompil…

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## [Best library for visualizing time series](https://discourse.julialang.org/t/best-library-for-visualizing-time-series/86602)

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**Author:** [@mariuszoican](https://discourse.julialang.org/u/mariuszoican)\
**Replies:** 12\
**Last updated:** [August 31, 2022, 5:45pm UTC](https://discourse.julialang.org/t/best-library-for-visualizing-time-series/86602 "2022-08-31T17:45:45Z")

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Hello, I was wondering what is the best library for visualizing time series? I’m coming from Python, where I’m using matplotlib and seaborn. Tried Gadfly, but it’s not very prone customization – I couldn’t figure out ho…

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