# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=56

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

**Page:** 57

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## [Extracting internally computed array from \`KrylovKit.eigsolve\` (without forking)](https://discourse.julialang.org/t/extracting-internally-computed-array-from-krylovkit-eigsolve-without-forking/130161)

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**Author:** [@NitinGupta](https://discourse.julialang.org/u/NitinGupta)\
**Replies:** 6\
**Last updated:** [June 24, 2025, 12:51pm UTC](https://discourse.julialang.org/t/extracting-internally-computed-array-from-krylovkit-eigsolve-without-forking/130161 "2025-06-24T12:51:59Z")

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I’d like to access the array T defined at line 44 of KrylovKit.jl/src/eigsolve/lanczos external to the function KrylovKit.eigsolve i.e. I want that eigsolve return T as well. What is the best way to go about this withou…

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## [Exact Cygwin package versions when building Julia](https://discourse.julialang.org/t/exact-cygwin-package-versions-when-building-julia/130162)

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**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 0\
**Last updated:** [June 24, 2025, 10:58am UTC](https://discourse.julialang.org/t/exact-cygwin-package-versions-when-building-julia/130162 "2025-06-24T10:58:56Z")

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Hi, I have moved to a new computer and struggling to build Julia from source on Windows with Cygwin. I am getting a message error saying: fatal error: mm\_malloc.h : No such file or directory. Is there a way to know w…

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## [How to forward differentiate a complex function?](https://discourse.julialang.org/t/how-to-forward-differentiate-a-complex-function/130127)

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**Author:** [@albertomercurio](https://discourse.julialang.org/u/albertomercurio)\
**Replies:** 19\
**Last updated:** [June 24, 2025, 10:13am UTC](https://discourse.julialang.org/t/how-to-forward-differentiate-a-complex-function/130127 "2025-06-24T10:13:02Z")

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Hello, I have a very basic question, but I haven’t found any solution. I want to differentiate a holomorphic complex function. My function is f(z) = \[z^3 + exp(im\*z), exp(im\*z^2) + 1\] And I differentiate it using Dif…

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## [Problem loading ducklake extension](https://discourse.julialang.org/t/problem-loading-ducklake-extension/130154)

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**Author:** [@kobusherbst](https://discourse.julialang.org/u/kobusherbst)\
**Replies:** 1\
**Last updated:** [June 24, 2025, 5:24am UTC](https://discourse.julialang.org/t/problem-loading-ducklake-extension/130154 "2025-06-24T05:24:28Z")

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When trying to load the ducklake extension in DuckDB v1.3.1 I get the following error: ERROR: Execute of query "LOAD ducklake;" failed: HTTP Error: Failed to download extension "ducklake" at URL "http://extensions.duckd…

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## [Has anyone added a MyST markdown extension to Julia?](https://discourse.julialang.org/t/has-anyone-added-a-myst-markdown-extension-to-julia/83289)

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**Author:** [@cadojo](https://discourse.julialang.org/u/cadojo)\
**Replies:** 3\
**Last updated:** [June 23, 2025, 9:01pm UTC](https://discourse.julialang.org/t/has-anyone-added-a-myst-markdown-extension-to-julia/83289 "2025-06-23T21:01:22Z")

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The good folks over at Executable Books have developed a new markdown flavor which adds support for function-like operations, citations, custom labeling, and more. The new markdown flavor is called MyST. Is this availa…

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## [How to properly do thread-safe element-wise mutation on atomic fields?](https://discourse.julialang.org/t/how-to-properly-do-thread-safe-element-wise-mutation-on-atomic-fields/130138)

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**Author:** [@frankwswang](https://discourse.julialang.org/u/frankwswang)\
**Replies:** 4\
**Last updated:** [June 23, 2025, 7:57pm UTC](https://discourse.julialang.org/t/how-to-properly-do-thread-safe-element-wise-mutation-on-atomic-fields/130138 "2025-06-23T19:57:52Z")

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MWE: julia\> mutable struct Atomic{T} @atomic a::T end julia\> obj1 = Atomic(collect(1:4)) Atomic{Vector{Int64}}(\[1, 2, 3, 4\]) julia\> obj1.a .= 2 4-element Vector{Int64}: 2 2 2 2 Unlike directly c…

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## [How to get ranges of valid data in vectors or dataframes?](https://discourse.julialang.org/t/how-to-get-ranges-of-valid-data-in-vectors-or-dataframes/129985)

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**Author:** [@Ju\_ska](https://discourse.julialang.org/u/Ju_ska)\
**Replies:** 7\
**Last updated:** [June 23, 2025, 6:59pm UTC](https://discourse.julialang.org/t/how-to-get-ranges-of-valid-data-in-vectors-or-dataframes/129985 "2025-06-23T18:59:08Z")

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Hi, using DataFrames df = DataFrame(col1 = \[1, NaN, 3, 4, NaN, 6, 7, 8, 9, 10, NaN, NaN\], col2 = \[missing, 2, 3, 4, 5, 6, missing, 8, 9, 10, 11, 12\]) 12×2 DataFrame Row │ col1 col2 │ Float64 Int64? ──…

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## [Security Advisory: HTMLSanitizer.jl](https://discourse.julialang.org/t/security-advisory-htmlsanitizer-jl/130136)

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**Author:** [@avik](https://discourse.julialang.org/u/avik)\
**Replies:** 0\
**Last updated:** [June 23, 2025, 2:29pm UTC](https://discourse.julialang.org/t/security-advisory-htmlsanitizer-jl/130136 "2025-06-23T14:29:13Z")

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There is a known vulnerability in the HTMLSanitzer.jl package in all versions below v0.2.1. We recommend all users upgrade to version v0.2.1 as soon as possible. More details here: Possible XSS in HTMLSanitizer when usi…

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## [Custom \`id\` for \`RuntimeGeneratedFunction\`](https://discourse.julialang.org/t/custom-id-for-runtimegeneratedfunction/130129)

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**Author:** [@sstroemer](https://discourse.julialang.org/u/sstroemer)\
**Replies:** 1\
**Last updated:** [June 23, 2025, 2:14pm UTC](https://discourse.julialang.org/t/custom-id-for-runtimegeneratedfunction/130129 "2025-06-23T14:14:29Z")

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I have a code that calls code\_ex = Meta.parse("""begin\\n$(code)\\nend""") @RuntimeGeneratedFunction( :(function (\_\_virtual\_\_::Virtual) # \[...\] try $code\_ex cat…

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## [Multithreading a over a double for-loop with arrays](https://discourse.julialang.org/t/multithreading-a-over-a-double-for-loop-with-arrays/130033)

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**Author:** [@Menno](https://discourse.julialang.org/u/Menno)\
**Replies:** 6\
**Last updated:** [June 23, 2025, 1:54pm UTC](https://discourse.julialang.org/t/multithreading-a-over-a-double-for-loop-with-arrays/130033 "2025-06-23T13:54:16Z")

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Hey there, I’m trying to multithread some elaborate test over two for-loops.The important piece of code is Threads.@threads for i in 1:length(t\_values) Threads.@threads for μ in 1:P m\_values\[μ,i\]=run\_test(i, μ, t0…

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## [MethodError For Defined Function](https://discourse.julialang.org/t/methoderror-for-defined-function/130130)

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**Author:** [@yoh-meyers](https://discourse.julialang.org/u/yoh-meyers)\
**Replies:** 4\
**Last updated:** [June 23, 2025, 1:28pm UTC](https://discourse.julialang.org/t/methoderror-for-defined-function/130130 "2025-06-23T13:28:45Z")

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Hello, I am back to using Julia, since more than 3 years break from the language. So I may not be most up-to-date with the latest changes. That said, I am using my package DanceJL and am running into a MethodError, fo…

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## [My latex inside doc doesn't appear correctly](https://discourse.julialang.org/t/my-latex-inside-doc-doesnt-appear-correctly/130128)

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**Author:** [@AbdelazimHussien](https://discourse.julialang.org/u/AbdelazimHussien)\
**Replies:** 5\
**Last updated:** [June 23, 2025, 1:23pm UTC](https://discourse.julialang.org/t/my-latex-inside-doc-doesnt-appear-correctly/130128 "2025-06-23T13:23:15Z")

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Hello everyone, I am developing a new package https://github.com/AbdelazimHussien/MetaheuristicsAlgorithms.jl Now, I am trying to display the equation in latex format but it doesn’t work. For example Engineering\_F3 sho…

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## [Type instability of reference struct member](https://discourse.julialang.org/t/type-instability-of-reference-struct-member/130111)

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**Author:** [@atteson](https://discourse.julialang.org/u/atteson)\
**Replies:** 3\
**Last updated:** [June 22, 2025, 7:53pm UTC](https://discourse.julialang.org/t/type-instability-of-reference-struct-member/130111 "2025-06-22T19:53:31Z")

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Why is the first function below type stable and the second not? test( rv::Ref{V} ) where V = rv\[\] @code\_warntype test( Ref(0x1) ) struct T{V} root::Ref{V} end t = T( Ref(0x1) ) test( t::T{V} ) where V = t.root\[\] @c…

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## [How to access columns from Vector{SVector{4,Float64}}?](https://discourse.julialang.org/t/how-to-access-columns-from-vector-svector-4-float64/130101)

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**Author:** [@fusion809](https://discourse.julialang.org/u/fusion809)\
**Replies:** 7\
**Last updated:** [June 22, 2025, 8:58am UTC](https://discourse.julialang.org/t/how-to-access-columns-from-vector-svector-4-float64/130101 "2025-06-22T08:58:19Z")

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I have this script file. I originally planned to utilize my own ODE solver called RKF45 but convergence issues prevented that and I fell back on using ODEProblem and solve from DifferentialEquations. I had written my ODE…

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## [Copying bytes from AbstractVector to Ptr](https://discourse.julialang.org/t/copying-bytes-from-abstractvector-to-ptr/119408)

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**Author:** [@nhz2](https://discourse.julialang.org/u/nhz2)\
**Replies:** 7\
**Last updated:** [June 21, 2025, 8:48pm UTC](https://discourse.julialang.org/t/copying-bytes-from-abstractvector-to-ptr/119408 "2025-06-21T20:48:13Z")

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I am trying to efficiently copy data from an AbstractVector{UInt8} into a Ptr{UInt8} I currently have tried the following: function unsafe\_read1!( dest::Ptr{UInt8}, src::AbstractVector{UInt8}, s…

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## [Simple animation with Makie](https://discourse.julialang.org/t/simple-animation-with-makie/109439)

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**Author:** [@Gravlax](https://discourse.julialang.org/u/Gravlax)\
**Replies:** 8\
**Last updated:** [June 21, 2025, 4:53pm UTC](https://discourse.julialang.org/t/simple-animation-with-makie/109439 "2025-06-21T16:53:11Z")

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I would like to generate a gif (or mkv) from a loop within which a figure is created at each iteration. Most Makie example I saw first create a figure, then modify it in an iteration. Could someone help me getting this P…

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## [Julia won't open after updating MacOS "julia” can’t be opened because Julia is not allowed.."](https://discourse.julialang.org/t/julia-wont-open-after-updating-macos-julia-can-t-be-opened-because-julia-is-not-allowed/126199)

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**Author:** [@PeX](https://discourse.julialang.org/u/PeX)\
**Replies:** 24\
**Last updated:** [June 21, 2025, 10:33am UTC](https://discourse.julialang.org/t/julia-wont-open-after-updating-macos-julia-can-t-be-opened-because-julia-is-not-allowed/126199 "2025-06-21T10:33:14Z")

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Hi all, I’m using MacBook and after the last update (Sequoia 15.3.1) when I try to open Julia I get the error: " “julia” can’t be opened because Julia is not allowed to open documents in Terminal." I believe this is r…

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## [Best Practices for Julia Pipelines Handling Real‑Time IoT Sensor Streams](https://discourse.julialang.org/t/best-practices-for-julia-pipelines-handling-real-time-iot-sensor-streams/130074)

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**Author:** [@ariajames](https://discourse.julialang.org/u/ariajames)\
**Replies:** 1\
**Last updated:** [June 20, 2025, 8:13pm UTC](https://discourse.julialang.org/t/best-practices-for-julia-pipelines-handling-real-time-iot-sensor-streams/130074 "2025-06-20T20:13:03Z")

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Hi everyone, I’m building a real-time IoT data pipeline in Julia to process and analyze sensor information from home automation devices. Has anyone here implemented a production-ready Julia pipeline for live IoT feeds? …

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## [The "nightly" distribution for apple.darwin14 is missing in juliaup](https://discourse.julialang.org/t/the-nightly-distribution-for-apple-darwin14-is-missing-in-juliaup/130069)

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**Author:** [@Herve](https://discourse.julialang.org/u/Herve)\
**Replies:** 9\
**Last updated:** [June 20, 2025, 7:39pm UTC](https://discourse.julialang.org/t/the-nightly-distribution-for-apple-darwin14-is-missing-in-juliaup/130069 "2025-06-20T19:39:22Z")

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Hi. Wanting to experiment with the nightly build on my laptop (oldish Macbook pro), I looked up the juliaup list of available builds. And the “nightly” is nowhere to be found. I checked it over several weeks, and no “nig…

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## [How to avoid naming conflicts](https://discourse.julialang.org/t/how-to-avoid-naming-conflicts/130070)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [June 20, 2025, 7:17pm UTC](https://discourse.julialang.org/t/how-to-avoid-naming-conflicts/130070 "2025-06-20T19:17:01Z")

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I am in charge of about 10 packages which get frequently updated. How can I avoid that someone exports a name from a package that conflicts with another exported name within our eco-system before making a new release? I…

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## [Implementation for AbstractVector with limited storage](https://discourse.julialang.org/t/implementation-for-abstractvector-with-limited-storage/130064)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 2\
**Last updated:** [June 20, 2025, 5:42pm UTC](https://discourse.julialang.org/t/implementation-for-abstractvector-with-limited-storage/130064 "2025-06-20T17:42:30Z")

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I am solving a problem where for each set of parameters, I can have 1–4 outcomes. How many depends on the parameters. Currently I am using something not unlike solutions = Vector{T}() # T is calculated before, it is an…

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## [Logging with some math output](https://discourse.julialang.org/t/logging-with-some-math-output/130062)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 0\
**Last updated:** [June 20, 2025, 2:18pm UTC](https://discourse.julialang.org/t/logging-with-some-math-output/130062 "2025-06-20T14:18:03Z")

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I intend to use a logger to provide a log with a large number of messages on convergence statistics, what the code did, and stuff that might help with debugging. My current plan is to use a combination of LoggingExtras a…

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## [Type alias and type piracy](https://discourse.julialang.org/t/type-alias-and-type-piracy/129845)

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**Author:** [@FerreolS](https://discourse.julialang.org/u/FerreolS)\
**Replies:** 11\
**Last updated:** [June 20, 2025, 1:27pm UTC](https://discourse.julialang.org/t/type-alias-and-type-piracy/129845 "2025-06-20T13:27:36Z")

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Hi If I declare an alias such as const MyType = YourType{2} and I implement let say Base.show(io::IO, x::MyType,...), I suppose it is type piracy. However, when composing different package it is tempting to do such pir…

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## [What is the proper way to benchmark a using statement?](https://discourse.julialang.org/t/what-is-the-proper-way-to-benchmark-a-using-statement/130029)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 9\
**Last updated:** [June 19, 2025, 11:40pm UTC](https://discourse.julialang.org/t/what-is-the-proper-way-to-benchmark-a-using-statement/130029 "2025-06-19T23:40:52Z")

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If calling a using statement for the first time since restart, it takes longer than calling after that in a different Julia instance: First instance since restart julia\> @time using SpecialFunctions 1.596852 seconds …

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## [Repeated linear least squares problem with large dimensions](https://discourse.julialang.org/t/repeated-linear-least-squares-problem-with-large-dimensions/130023)

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**Author:** [@JADekker](https://discourse.julialang.org/u/JADekker)\
**Replies:** 6\
**Last updated:** [June 19, 2025, 6:17pm UTC](https://discourse.julialang.org/t/repeated-linear-least-squares-problem-with-large-dimensions/130023 "2025-06-19T18:17:55Z")

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Hi, I’m working with a larger algorithm in which a recurring step (done 5 - 20 times) is to carry out a linear regression y^k = X\\beta^k + \\varepsilon^k with roughly 100.000 observations and 1.000-5.000 variables, where…

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## [FixedSizeVectors with cache-aligned memory?](https://discourse.julialang.org/t/fixedsizevectors-with-cache-aligned-memory/129884)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 18\
**Last updated:** [June 19, 2025, 7:33pm UTC](https://discourse.julialang.org/t/fixedsizevectors-with-cache-aligned-memory/129884 "2025-06-19T19:33:33Z")

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FixedSizeVectors offer a first, more performant and cleaner approach to working with (generally, numeric) vectors where, once formed, the size of the vector does not change. AlignedAllocs provides cache-aligned memory a…

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## [Extract Julia version from the manifest](https://discourse.julialang.org/t/extract-julia-version-from-the-manifest/130030)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 2\
**Last updated:** [June 19, 2025, 7:14pm UTC](https://discourse.julialang.org/t/extract-julia-version-from-the-manifest/130030 "2025-06-19T19:14:38Z")

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I want to start a computation using the exact same Julia version that is in the manifest on a server, where I am using juliaup. It that exact same version is not available, I prefer to throw an error. I am unsure about …

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## [The Mismatch between pwd() and @\_\_DIR\_\_ and how it impacts packages like GLMakie](https://discourse.julialang.org/t/the-mismatch-between-pwd-and-dir-and-how-it-impacts-packages-like-glmakie/130036)

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**Author:** [@Maddy](https://discourse.julialang.org/u/Maddy)\
**Replies:** 1\
**Last updated:** [June 19, 2025, 6:02pm UTC](https://discourse.julialang.org/t/the-mismatch-between-pwd-and-dir-and-how-it-impacts-packages-like-glmakie/130036 "2025-06-19T18:02:57Z")

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When I run Julia in a modularised structure in VSCode and try accessing files in a folder sibling the the folder of the source file, all within a root project directory, something interesting happens. (All of the follow…

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## [TTFX for Julia 1.11 much faster than with Julia 1.10](https://discourse.julialang.org/t/ttfx-for-julia-1-11-much-faster-than-with-julia-1-10/130022)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 1\
**Last updated:** [June 19, 2025, 12:57pm UTC](https://discourse.julialang.org/t/ttfx-for-julia-1-11-much-faster-than-with-julia-1-10/130022 "2025-06-19T12:57:04Z")

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We see that the initialization of an MTK problem, using Julia 1.11 is much faster than with Julia 1.10. For details, see: System initialization on Julia 1.10 is slow · Issue #233 · ufechner7/KiteModels.jl · GitHub Julia…

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## [Measuring stats (cpu time etc.) for external program](https://discourse.julialang.org/t/measuring-stats-cpu-time-etc-for-external-program/130017)

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**Author:** [@bubaya](https://discourse.julialang.org/u/bubaya)\
**Replies:** 0\
**Last updated:** [June 19, 2025, 8:03am UTC](https://discourse.julialang.org/t/measuring-stats-cpu-time-etc-for-external-program/130017 "2025-06-19T08:03:15Z")

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I have a an external program prog, and I am writing a julia program that prepares various data sets and measures the run time of prog for each of the data sets. My question is about how to run prog. Of course, I am aware…

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