# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=9

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

**Page:** 10

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## [Save TDMS files](https://discourse.julialang.org/t/save-tdms-files/137317)

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**Author:** [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Replies:** 4\
**Last updated:** [May 29, 2026, 6:13am UTC](https://discourse.julialang.org/t/save-tdms-files/137317 "2026-05-29T06:13:28Z")

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Does a package exist to write data in NI compatible TDMS format? Here is my code, I am intersted to recieve your feedback: using PythonCall #: --- include Python-Package to write TDMS-File: nptdms = pyimport("nptdms") …

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## [Can I decide if a program needs thread-safety at compile time based on the threads available by the julia process?](https://discourse.julialang.org/t/can-i-decide-if-a-program-needs-thread-safety-at-compile-time-based-on-the-threads-available-by-the-julia-process/137321)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 7\
**Last updated:** [May 28, 2026, 8:43pm UTC](https://discourse.julialang.org/t/can-i-decide-if-a-program-needs-thread-safety-at-compile-time-based-on-the-threads-available-by-the-julia-process/137321 "2026-05-28T20:43:11Z")

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i.e. can I do something like const needs\_thread\_safety = Threads.nthreads() == 1 ? false : true and then use the constant to compile differently if it is true or false (disabling atomics and/or locks if false)? Or do I…

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## [https://juliahub.com/ui/Packages/General/FFMPEG give 404 page](https://discourse.julialang.org/t/https-juliahub-com-ui-packages-general-ffmpeg-give-404-page/137241)

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**Author:** [@devel-chm](https://discourse.julialang.org/u/devel-chm)\
**Replies:** 3\
**Last updated:** [May 28, 2026, 6:14pm UTC](https://discourse.julialang.org/t/https-juliahub-com-ui-packages-general-ffmpeg-give-404-page/137241 "2026-05-28T18:14:47Z")

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This has been happening for all packages I try to view via JuliaHub. I am able to get to the “source” repositories. Packages/FFMPEG Got a \*\*404\*\* when trying to retrieve package information. 🔨 Either this packa…

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## [Windows 11 KB5089573 multithreading issues](https://discourse.julialang.org/t/windows-11-kb5089573-multithreading-issues/137312)

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**Author:** [@arch-dev](https://discourse.julialang.org/u/arch-dev)\
**Replies:** 3\
**Last updated:** [May 28, 2026, 1:21pm UTC](https://discourse.julialang.org/t/windows-11-kb5089573-multithreading-issues/137312 "2026-05-28T13:21:20Z")

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Today, I’ve installed the KB5089573 update which brings the so called “Low Latency Profile” feature to Windows 11 (more information here). Up to now I’ve never had any issues with multithreading. My usage case is a while…

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## [How to combine @nospecialize with type parameters?](https://discourse.julialang.org/t/how-to-combine-nospecialize-with-type-parameters/137304)

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**Author:** [@matthias314](https://discourse.julialang.org/u/matthias314)\
**Replies:** 6\
**Last updated:** [May 28, 2026, 11:29am UTC](https://discourse.julialang.org/t/how-to-combine-nospecialize-with-type-parameters/137304 "2026-05-28T11:29:20Z")

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It seems that type parameters in functions prevent @nospecialize from having an effect: julia\> f(@nospecialize x::T) where T = 0; julia\> f(1); f(1.0); julia\> m = only(methods(f)); m.specializations |\> collect 7-elemen…

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## [Dictionary for thread-safe, limited memoization](https://discourse.julialang.org/t/dictionary-for-thread-safe-limited-memoization/137072)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 25\
**Last updated:** [May 27, 2026, 10:14pm UTC](https://discourse.julialang.org/t/dictionary-for-thread-safe-limited-memoization/137072 "2026-05-27T22:14:14Z")

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I am looking for a Dict-like type which allows me to keep only the last N values inserted, for some value of N::Int, is thread-safe. Background: memoization, where the resulting objects are large and I am unlike…

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## [UDPSocket()](https://discourse.julialang.org/t/udpsocket/137291)

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**Author:** [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Replies:** 4\
**Last updated:** [May 27, 2026, 3:09pm UTC](https://discourse.julialang.org/t/udpsocket/137291 "2026-05-27T15:09:54Z")

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I have severe problems to listen to a port on which an UDP-Socket server sends packages. I see the packages in Wireshark and my Python-Script can see the packages as well. But I struggle to achieve the same in Julia. …

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## [Readdlm with IOBuffer](https://discourse.julialang.org/t/readdlm-with-iobuffer/137275)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 6\
**Last updated:** [May 25, 2026, 6:36pm UTC](https://discourse.julialang.org/t/readdlm-with-iobuffer/137275 "2026-05-25T18:36:33Z")

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I have a ASCII datafile that has a number of different vectors and matrices within it. Once I have the file read, I can figure out what is vector and what is a matrix. I thought I would use readdlm to read the matrix, …

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## [Shorten type in stack trace](https://discourse.julialang.org/t/shorten-type-in-stack-trace/137259)

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**Author:** [@Tortar](https://discourse.julialang.org/u/Tortar)\
**Replies:** 4\
**Last updated:** [May 25, 2026, 12:37pm UTC](https://discourse.julialang.org/t/shorten-type-in-stack-trace/137259 "2026-05-25T12:37:18Z")

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I have this long stack trace like this one appearing when running the tests of the package, which originates from the fact that the type has many parameters: \[3\] finalize\_search\_and\_match!(world::Ark.World{Tuple{Ark.\_Co…

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## [Windows setup in an externally administered environment](https://discourse.julialang.org/t/windows-setup-in-an-externally-administered-environment/137255)

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**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 12\
**Last updated:** [May 24, 2026, 3:51pm UTC](https://discourse.julialang.org/t/windows-setup-in-an-externally-administered-environment/137255 "2026-05-24T15:51:16Z")

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Currently I have an old Mac at work, which will be replaced by a Windows computer. They are administered by an external company, who are usually forthcoming but sometimes slow. I will ask for local admin privileges, mayb…

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## [Common data utilities for time series](https://discourse.julialang.org/t/common-data-utilities-for-time-series/137104)

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**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 15\
**Last updated:** [May 23, 2026, 11:03pm UTC](https://discourse.julialang.org/t/common-data-utilities-for-time-series/137104 "2026-05-23T23:03:20Z")

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I frequently find myself having to cleanup and process raw ‘real’ data. I am really not a data person, but I think this is called data plumbing. And to be honest, I don’t have much fun doing it :slight\_smile: Typical op…

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## [Where are control flow labels fully documented?](https://discourse.julialang.org/t/where-are-control-flow-labels-fully-documented/137252)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [May 23, 2026, 7:23am UTC](https://discourse.julialang.org/t/where-are-control-flow-labels-fully-documented/137252 "2026-05-23T07:23:19Z")

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The documentation of @label is rather sparse. I am looking for a comprehensive list of which forms can be preceded by @label my\_label (apparently begin, for, what else?) which forms accept labels (eg break and @got…

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## [ForwardDiff Lie brackets allocate with StaticArrays](https://discourse.julialang.org/t/forwarddiff-lie-brackets-allocate-with-staticarrays/137248)

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**Author:** [@tremelow](https://discourse.julialang.org/u/tremelow)\
**Replies:** 0\
**Last updated:** [May 22, 2026, 9:34pm UTC](https://discourse.julialang.org/t/forwarddiff-lie-brackets-allocate-with-staticarrays/137248 "2026-05-22T21:34:52Z")

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I’m working on a code where I need Lie brackets of Lie brackets, but computing the Jacobian of a Lie bracket allocates data. Here’s a MWE using StaticArrays using BenchmarkTools import ForwardDiff f(x::SVector{2,T}) wh…

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## [Issues with Reactant unable to find GPU on Colab, but CUDA.jl can](https://discourse.julialang.org/t/issues-with-reactant-unable-to-find-gpu-on-colab-but-cuda-jl-can/129360)

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**Author:** [@arrowmancer](https://discourse.julialang.org/u/arrowmancer)\
**Replies:** 7\
**Last updated:** [May 21, 2026, 5:30pm UTC](https://discourse.julialang.org/t/issues-with-reactant-unable-to-find-gpu-on-colab-but-cuda-jl-can/129360 "2026-05-21T17:30:09Z")

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Hi guys, currently when using the Julia backend on Google Colab, I haven’t been able to get Reactant to find any Nvidia GPUs when I select a GPU runtime on Colab. E.g. when I select A100 or the L4 GPU, and then try to r…

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## [BlackBoxOptim.jl Documentation](https://discourse.julialang.org/t/blackboxoptim-jl-documentation/137213)

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**Author:** [@askvorts](https://discourse.julialang.org/u/askvorts)\
**Replies:** 1\
**Last updated:** [May 20, 2026, 3:34pm UTC](https://discourse.julialang.org/t/blackboxoptim-jl-documentation/137213 "2026-05-20T15:34:13Z")

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I just noticed that BlackBoxOptim.jl currently appears to have no documentation available. I’m wondering whether it was removed intentionally or if there’s another reason for this.

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## [Calculate return type of lu!(A)](https://discourse.julialang.org/t/calculate-return-type-of-lu-a/137210)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 4\
**Last updated:** [May 20, 2026, 2:20pm UTC](https://discourse.julialang.org/t/calculate-return-type-of-lu-a/137210 "2026-05-20T14:20:25Z")

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For a given A::M where M \<: AbstractMatrix, I would like to calculate typeof(lu!(A)) in the least brittle way. That is, without exposing internals if possible, without performing the calculation if possible, wor…

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## [Designing a C ABI layer for a multi-lingual project](https://discourse.julialang.org/t/designing-a-c-abi-layer-for-a-multi-lingual-project/137150)

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**Author:** [@BananaMaster3](https://discourse.julialang.org/u/BananaMaster3)\
**Replies:** 3\
**Last updated:** [May 20, 2026, 3:16am UTC](https://discourse.julialang.org/t/designing-a-c-abi-layer-for-a-multi-lingual-project/137150 "2026-05-20T03:16:15Z")

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Hello all, I’m interested in creating a multi-lingual project with a Julia backend. I’d like to do this through a C ABI layer and would like advice on how to structure it. Since my usecase is a bit difficult to explain…

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## [Converting an expression to a specific form with Symbolics.jl](https://discourse.julialang.org/t/converting-an-expression-to-a-specific-form-with-symbolics-jl/137160)

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**Author:** [@owiecc](https://discourse.julialang.org/u/owiecc)\
**Replies:** 1\
**Last updated:** [May 19, 2026, 8:14pm UTC](https://discourse.julialang.org/t/converting-an-expression-to-a-specific-form-with-symbolics-jl/137160 "2026-05-19T20:14:31Z")

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I would like to convert an expression to a specific mathematical form. Is this possible to do with Symbolics.jl (or any other package for that matter)? Specifically I would like to convert an arbitrary transfer function G…

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## [Missing documentation for \`this\` (actually not)](https://discourse.julialang.org/t/missing-documentation-for-this-actually-not/137185)

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**Author:** [@lilachint](https://discourse.julialang.org/u/lilachint)\
**Replies:** 5\
**Last updated:** [May 19, 2026, 12:19pm UTC](https://discourse.julialang.org/t/missing-documentation-for-this-actually-not/137185 "2026-05-19T12:19:53Z")

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I came across Base.jl include, and saw this. Since Julia is not OOP, I had never seen this before. The keyword is not even documented, searching gives 0 results. I tested it myself in REPL and this seems to be a referenc…

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## [Include inside and outside of module](https://discourse.julialang.org/t/include-inside-and-outside-of-module/137181)

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**Author:** [@jw3126](https://discourse.julialang.org/u/jw3126)\
**Replies:** 1\
**Last updated:** [May 19, 2026, 8:40am UTC](https://discourse.julialang.org/t/include-inside-and-outside-of-module/137181 "2026-05-19T08:40:02Z")

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In Julia, the following code is ideomatic: module A include("A.jl") end while module A end A.include("A.jl") is not. I 100% agree that the first option is more idiomatic, aesthetic, readable and should be preferred. …

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## [Plotting multiple lines between different points](https://discourse.julialang.org/t/plotting-multiple-lines-between-different-points/137155)

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**Author:** [@amca01](https://discourse.julialang.org/u/amca01)\
**Replies:** 5\
**Last updated:** [May 18, 2026, 7:32pm UTC](https://discourse.julialang.org/t/plotting-multiple-lines-between-different-points/137155 "2026-05-18T19:32:14Z")

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I have set of vertices, and for each vertex, a set of other vertices “adjacent” to it, given by a dictionary, For example: adj\[\[2,3\]\] = \[\[3,2\],\[1,0\],\[2,1\]\] What I want to do is to plot all the adjacencies. But this d…

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## [Modern approach to update an old package relying on PyCall and custom script to insall a python package](https://discourse.julialang.org/t/modern-approach-to-update-an-old-package-relying-on-pycall-and-custom-script-to-insall-a-python-package/137169)

<div class="topic-metadata">

**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [May 18, 2026, 6:26pm UTC](https://discourse.julialang.org/t/modern-approach-to-update-an-old-package-relying-on-pycall-and-custom-script-to-insall-a-python-package/137169 "2026-05-18T18:26:03Z")

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I am the maintainer of OdsIO, an old package that wrap ezodf python module to read and write data on ODS (LibreOffice) spreadsheets. This has been my first package and at that time I used PyCall and made the installatio…

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## [How to display images in Pluto?](https://discourse.julialang.org/t/how-to-display-images-in-pluto/50259)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 17\
**Last updated:** [May 18, 2026, 8:15am UTC](https://discourse.julialang.org/t/how-to-display-images-in-pluto/50259 "2026-05-18T08:15:39Z")

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I’ve seen a couple of threads discussion a bit of these but I couldn’t make it work for me in GMT.jl. There I have if (isdefined(Main, :IJulia) && Main.IJulia.inited) # From Jupyter? if (fname == "") display("imag…

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## [Julia auto-loaded modules](https://discourse.julialang.org/t/julia-auto-loaded-modules/137151)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 0\
**Last updated:** [May 18, 2026, 4:16am UTC](https://discourse.julialang.org/t/julia-auto-loaded-modules/137151 "2026-05-18T04:16:25Z")

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If I launch a clean Julia session, I get: julia\> keys(Base.loaded\_modules) KeySet for a Dict{Base.PkgId, Module} with 12 entries. Keys: Base.PkgId(Base.UUID("4536629a-c528-5b80-bd46-f80d51c5b363"), "OpenBLAS\_jll") B…

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## [Performance of Julia binary wrapper behind Matlab mex-file interface performance](https://discourse.julialang.org/t/performance-of-julia-binary-wrapper-behind-matlab-mex-file-interface-performance/126946)

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**Author:** [@andreasvarga](https://discourse.julialang.org/u/andreasvarga)\
**Replies:** 38\
**Last updated:** [May 17, 2026, 11:00pm UTC](https://discourse.julialang.org/t/performance-of-julia-binary-wrapper-behind-matlab-mex-file-interface-performance/126946 "2026-05-17T23:00:44Z")

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Recently I implemented a julia wrapper for a subroutine of the SLICOT library (specifically SB03MD to solve Lyapunov matrix equations). I used the generated binary wrappers in conjunction with Intel’s MKL, which is used…

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## [Temporarily disable Project.toml "sources" so I can \`dev\` the local dependency version instead](https://discourse.julialang.org/t/temporarily-disable-project-toml-sources-so-i-can-dev-the-local-dependency-version-instead/137082)

<div class="topic-metadata">

**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 2\
**Last updated:** [May 17, 2026, 11:06am UTC](https://discourse.julialang.org/t/temporarily-disable-project-toml-sources-so-i-can-dev-the-local-dependency-version-instead/137082 "2026-05-17T11:06:42Z")

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I have a personal package MyPackage that depends on another personal package MyPackageDependency. I am using the sources section of the MyPackage Project.toml file to point to the MyPackageDependency GitHub repository. H…

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## [Type stability and tasks](https://discourse.julialang.org/t/type-stability-and-tasks/137136)

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**Author:** [@moble](https://discourse.julialang.org/u/moble)\
**Replies:** 6\
**Last updated:** [May 16, 2026, 2:12pm UTC](https://discourse.julialang.org/t/type-stability-and-tasks/137136 "2026-05-16T14:12:14Z")

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I’m looking into using tasks for some parallelization speedup, but I’m worried about type stability in the returned objects. For example, I’m calling a type-stable function over a range of Ints; the returned objects sho…

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## [Does Julia support symbolic computation?](https://discourse.julialang.org/t/does-julia-support-symbolic-computation/104306)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 11\
**Last updated:** [May 15, 2026, 4:56pm UTC](https://discourse.julialang.org/t/does-julia-support-symbolic-computation/104306 "2026-05-15T16:56:48Z")

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Does Julia support symbolic computation? For example, I would like to perform symbolic matrix operations or simplify algebraic expressions. What is the best way to achieve this? Thanks!

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## [Registry fails to download with certificate error in 1.10.11](https://discourse.julialang.org/t/registry-fails-to-download-with-certificate-error-in-1-10-11/136390)

<div class="topic-metadata">

**Author:** [@co1emi11er](https://discourse.julialang.org/u/co1emi11er)\
**Replies:** 9\
**Last updated:** [May 15, 2026, 2:29pm UTC](https://discourse.julialang.org/t/registry-fails-to-download-with-certificate-error-in-1-10-11/136390 "2026-05-15T14:29:50Z")

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What happened between 1.10.10 and 1.10.11 that would have broken the registry for me? I am on a work computer, so it is a certification issue. Julia 1.10.10 Julia 1.10.11 I can’t really download packages anymore. …

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## [Debugger no longer hits breakpoints in VSC?](https://discourse.julialang.org/t/debugger-no-longer-hits-breakpoints-in-vsc/136161)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 22\
**Last updated:** [May 15, 2026, 2:28pm UTC](https://discourse.julialang.org/t/debugger-no-longer-hits-breakpoints-in-vsc/136161 "2026-05-15T14:28:57Z")

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When now do @run ... no breakpoints are hit. That means no debugger at all- Only me?

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