# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=8

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

**Page:** 9

---

## [If I clone a Julia package from git, should the local folder have the ending .jl?](https://discourse.julialang.org/t/if-i-clone-a-julia-package-from-git-should-the-local-folder-have-the-ending-jl/137522)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 11\
**Last updated:** [June 9, 2026, 12:44pm UTC](https://discourse.julialang.org/t/if-i-clone-a-julia-package-from-git-should-the-local-folder-have-the-ending-jl/137522 "2026-06-09T12:44:58Z")

</div>

I am a bit confused: If I clone a package using the URL provided by GitHub (see picture) using git clone https://github.com/OpenSourceAWE/KiteUtils.jl.git I get a local folder named KiteUtils.jl. If I do \]dev Kit…

---

## [Kaimon returning empty results](https://discourse.julialang.org/t/kaimon-returning-empty-results/137505)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 3\
**Last updated:** [June 9, 2026, 7:20am UTC](https://discourse.julialang.org/t/kaimon-returning-empty-results/137505 "2026-06-09T07:20:08Z")

</div>

I keep getting these message: Hmm, the kaimon tool keeps returning empty results even when I use q=false. Let me check the session status and try a different approach. Working when using Kaimon.jl with Deepseek V4 fla…

---

## [Setting Conda enviroment as Python executable for PyCall.jl](https://discourse.julialang.org/t/setting-conda-enviroment-as-python-executable-for-pycall-jl/125132)

<div class="topic-metadata">

**Author:** [@AntonioMoralesPerez](https://discourse.julialang.org/u/AntonioMoralesPerez)\
**Replies:** 2\
**Last updated:** [June 9, 2026, 6:40am UTC](https://discourse.julialang.org/t/setting-conda-enviroment-as-python-executable-for-pycall-jl/125132 "2026-06-09T06:40:17Z")

</div>

I tried to change the Python executable on PyCall.jl but it doesn’t change after building. Some code showing my problem: ❯ julia \_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_)…

---

## [Pluto Notebook Excessive Compute Time with PlotlyJS](https://discourse.julialang.org/t/pluto-notebook-excessive-compute-time-with-plotlyjs/122854)

<div class="topic-metadata">

**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 11\
**Last updated:** [June 8, 2026, 9:11pm UTC](https://discourse.julialang.org/t/pluto-notebook-excessive-compute-time-with-plotlyjs/122854 "2026-06-08T21:11:34Z")

</div>

I have a Pluto notebook with about 13 cells, most of which have a variable number of lines between the begin and end. When I take a look at the sum total of the time taken to execute each cell as reported by Pluto, it t…

---

## [Struggling with Symbolics matrix multiplication](https://discourse.julialang.org/t/struggling-with-symbolics-matrix-multiplication/137476)

<div class="topic-metadata">

**Author:** [@ea42gh](https://discourse.julialang.org/u/ea42gh)\
**Replies:** 3\
**Last updated:** [June 8, 2026, 1:36pm UTC](https://discourse.julialang.org/t/struggling-with-symbolics-matrix-multiplication/137476 "2026-06-08T13:36:04Z")

</div>

Newbie Symbolics question. I have two matrices with element type Int L = \[1 0 0 0; -3 1 0 0; 2 3 1 0; -2 3 -2 1\] D = \[1 0 0 0; 0 2 0 0; 0 0 1 0; 0 0 0 2\] Forming the product G = Num.(L) \* sqrt( Num.(D) ) yields …

---

## [Writing on external temporary files with MPI.jl](https://discourse.julialang.org/t/writing-on-external-temporary-files-with-mpi-jl/137485)

<div class="topic-metadata">

**Author:** [@phx](https://discourse.julialang.org/u/phx)\
**Replies:** 3\
**Last updated:** [June 7, 2026, 11:34pm UTC](https://discourse.julialang.org/t/writing-on-external-temporary-files-with-mpi-jl/137485 "2026-06-07T23:34:37Z")

</div>

Hi all. I’m learning how to use MPI with Julia, specifically the MPI.jl package. I’m trying to understand how to print on external temporary files, and I can’t make it work. This is my current minimal non-working examp…

---

## [Writing to a shared buffer in multi-threaded for loop](https://discourse.julialang.org/t/writing-to-a-shared-buffer-in-multi-threaded-for-loop/137373)

<div class="topic-metadata">

**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 17\
**Last updated:** [June 7, 2026, 5:53pm UTC](https://discourse.julialang.org/t/writing-to-a-shared-buffer-in-multi-threaded-for-loop/137373 "2026-06-07T17:53:38Z")

</div>

I have a for loop that iterates over millions of elements, each of which are processed quickly. Elements update random parts of a shared buffer. I’m trying to parallelize this operation in a performant way. I have consid…

---

## [Reading Fortran-style Complex Numbers From File](https://discourse.julialang.org/t/reading-fortran-style-complex-numbers-from-file/137453)

<div class="topic-metadata">

**Author:** [@ducksoverip](https://discourse.julialang.org/u/ducksoverip)\
**Replies:** 14\
**Last updated:** [June 7, 2026, 2:56am UTC](https://discourse.julialang.org/t/reading-fortran-style-complex-numbers-from-file/137453 "2026-06-07T02:56:47Z")

</div>

Part of my inherited research code is a highly parallelized Fortran90 program that produces, as its primary output, a large text file (~1 GB) of complex numbers in the following format: (1.014631909321741E-002,-1.82546…

---

## [GTK screen updating](https://discourse.julialang.org/t/gtk-screen-updating/137322)

<div class="topic-metadata">

**Author:** [@isaac-aderemi](https://discourse.julialang.org/u/isaac-aderemi)\
**Replies:** 1\
**Last updated:** [June 6, 2026, 5:50pm UTC](https://discourse.julialang.org/t/gtk-screen-updating/137322 "2026-06-06T17:50:30Z")

</div>

My question How does a person update the screen in gtk for a game or video updating? notes Glade was used to make the following code and I was wondering how I would update the screen (the ppm that is currently being use…

---

## [Best practice: threaded sparse matrix assembly](https://discourse.julialang.org/t/best-practice-threaded-sparse-matrix-assembly/137447)

<div class="topic-metadata">

**Author:** [@tduretz](https://discourse.julialang.org/u/tduretz)\
**Replies:** 13\
**Last updated:** [June 6, 2026, 1:57pm UTC](https://discourse.julialang.org/t/best-practice-threaded-sparse-matrix-assembly/137447 "2026-06-06T13:57:05Z")

</div>

What is current state-of-the-art regarding threaded sparse matrix assembly? We’re currently having an issue where sparse matrix assembly is taking more time than the linear solver (at low resolutions). One way to improv…

---

## [Juliaup cannot find Julia](https://discourse.julialang.org/t/juliaup-cannot-find-julia/137462)

<div class="topic-metadata">

**Author:** [@huang\_min](https://discourse.julialang.org/u/huang_min)\
**Replies:** 5\
**Last updated:** [June 6, 2026, 9:32am UTC](https://discourse.julialang.org/t/juliaup-cannot-find-julia/137462 "2026-06-06T09:32:46Z")

</div>

I am using Ubuntu under WSL2. Yesterday morning, everything was fine and I did not do anything to the system. However, around evening, Juliaup could not find Julia any more. Actually, I was using the same screen in the m…

---

## [Anyone having performance issues with create\_sysimage on Fedora?](https://discourse.julialang.org/t/anyone-having-performance-issues-with-create-sysimage-on-fedora/137454)

<div class="topic-metadata">

**Author:** [@Deduction42](https://discourse.julialang.org/u/Deduction42)\
**Replies:** 6\
**Last updated:** [June 5, 2026, 10:50pm UTC](https://discourse.julialang.org/t/anyone-having-performance-issues-with-create-sysimage-on-fedora/137454 "2026-06-05T22:50:16Z")

</div>

I just started using Fedora, and tried using create\_sysimage on a project that usually takes 5 minutes minutes to complete on Windows/Ubuntu. After building it in Windows, with PackageCompiler v2.3.0, I tried building it…

---

## [When could I need more threads than CPU cores, given 1.7+ task migration?](https://discourse.julialang.org/t/when-could-i-need-more-threads-than-cpu-cores-given-1-7-task-migration/137315)

<div class="topic-metadata">

**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 16\
**Last updated:** [June 5, 2026, 2:36pm UTC](https://discourse.julialang.org/t/when-could-i-need-more-threads-than-cpu-cores-given-1-7-task-migration/137315 "2026-06-05T14:36:24Z")

</div>

Title basically says it all. To elaborate, the number of OS threads running in parallel is at most the number of virtual CPU cores. The reason for having many more threads is that some threads can or must idle, so there…

---

## [Wrapping a CLI tool into a julia package](https://discourse.julialang.org/t/wrapping-a-cli-tool-into-a-julia-package/137440)

<div class="topic-metadata">

**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 2\
**Last updated:** [June 3, 2026, 10:19pm UTC](https://discourse.julialang.org/t/wrapping-a-cli-tool-into-a-julia-package/137440 "2026-06-03T22:19:45Z")

</div>

I have been thinking about XML schema validation in julia for a little while now. I just had an idea that I would like some feedback on: Is it possible to take a CLI tool (I am thinking of the rust-based GitHub - Frankl…

---

## [Secure coding in Julia?](https://discourse.julialang.org/t/secure-coding-in-julia/115972)

<div class="topic-metadata">

**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 19\
**Last updated:** [June 3, 2026, 9:36pm UTC](https://discourse.julialang.org/t/secure-coding-in-julia/115972 "2026-06-03T21:36:22Z")

</div>

Hi all, Someone asked a question on the ModernJuliaWorkflows repo, and I have no clue how to answer. They are looking for tools related to SAST (Static Analysis Security Testing) and SCA (Software Composition Analysis) …

---

## [Adjoint or transpose of Char or Vector{Char}](https://discourse.julialang.org/t/adjoint-or-transpose-of-char-or-vector-char/137412)

<div class="topic-metadata">

**Author:** [@jecs](https://discourse.julialang.org/u/jecs)\
**Replies:** 1\
**Last updated:** [June 2, 2026, 9:34pm UTC](https://discourse.julialang.org/t/adjoint-or-transpose-of-char-or-vector-char/137412 "2026-06-02T21:34:28Z")

</div>

Scalar case: julia\> 1' 1 julia\> 'a'' ERROR: MethodError: no method matching adjoint(::Char) The function \`adjoint\` exists, but no method is defined for this combination of argument types. ... Vector case: julia\> \[1…

---

## [Using textures with Raycore.jl](https://discourse.julialang.org/t/using-textures-with-raycore-jl/137404)

<div class="topic-metadata">

**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\
**Replies:** 1\
**Last updated:** [June 2, 2026, 5:09pm UTC](https://discourse.julialang.org/t/using-textures-with-raycore-jl/137404 "2026-06-02T17:09:24Z")

</div>

I want to render computer graphics images from triangular mesh models. I found that Raycore.jl does a great job of optimizing the model. The examples in the documentation focus on raytracing without textures, though. How…

---

## [Accessing a column from a vector of vectors](https://discourse.julialang.org/t/accessing-a-column-from-a-vector-of-vectors/136722)

<div class="topic-metadata">

**Author:** [@Ju\_ska](https://discourse.julialang.org/u/Ju_ska)\
**Replies:** 9\
**Last updated:** [June 2, 2026, 10:45am UTC](https://discourse.julialang.org/t/accessing-a-column-from-a-vector-of-vectors/136722 "2026-06-02T10:45:25Z")

</div>

Hi, I have something like: a = \[\["a", "1" ,"11"\], \["b", "2" ,"22"\], \["c", "3" ,"33"\]\] 3-element Vector{Vector{String}}: \["a", "1", "11"\] \["b", "2", "22"\] \["c", "3", "33"\] And I would like to get e.g. th…

---

## [Perf Julia@threads behind Numba@njit(parallel=True)](https://discourse.julialang.org/t/perf-julia-threads-behind-numba-njit-parallel-true/137388)

<div class="topic-metadata">

**Author:** [@cheng.wu](https://discourse.julialang.org/u/cheng.wu)\
**Replies:** 17\
**Last updated:** [June 2, 2026, 9:59am UTC](https://discourse.julialang.org/t/perf-julia-threads-behind-numba-njit-parallel-true/137388 "2026-06-02T09:59:33Z")

</div>

(This is a follow up to Julia vs Numba, having created a new discourse account) I came across this article on the performance of Julia vs Python+Numba, and this section interested me. It claims parallel Julia code is qu…

---

## [Apple Accelerate Sparse Solvers](https://discourse.julialang.org/t/apple-accelerate-sparse-solvers/110175)

<div class="topic-metadata">

**Author:** [@jdlara-berkeley](https://discourse.julialang.org/u/jdlara-berkeley)\
**Replies:** 14\
**Last updated:** [June 1, 2026, 8:24pm UTC](https://discourse.julialang.org/t/apple-accelerate-sparse-solvers/110175 "2026-06-01T20:24:04Z")

</div>

I am trying to wrap the calls for Apple’s Accelerate Sparse Solver and it is my first try at wrapping apple routines. I am following some of the code structure in Accelerate.jl and LinearSolvers.jl but I keep failing at…

---

## [Why is \`\]add --preserve=all\` still updating packages?](https://discourse.julialang.org/t/why-is-add-preserve-all-still-updating-packages/137368)

<div class="topic-metadata">

**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 0\
**Last updated:** [June 1, 2026, 8:23am UTC](https://discourse.julialang.org/t/why-is-add-preserve-all-still-updating-packages/137368 "2026-06-01T08:23:36Z")

</div>

I have an environment where GPUArrays is already installed as an indirect dependency. I want to make it available without triggering precompilation (which can be really slow sometimes). But even with --preserve=all the…

---

## [HTTP.jl 2.0 not pre-compiling](https://discourse.julialang.org/t/http-jl-2-0-not-pre-compiling/137367)

<div class="topic-metadata">

**Author:** [@TimG](https://discourse.julialang.org/u/TimG)\
**Replies:** 1\
**Last updated:** [June 1, 2026, 8:11am UTC](https://discourse.julialang.org/t/http-jl-2-0-not-pre-compiling/137367 "2026-06-01T08:11:53Z")

</div>

Precompilation of Reseau.jl completes as expected but then HTTP.jl precompilation just hangs. I’ve tried it multiple times and each time it just sits with the spinning disk indefinitely. It didn’t work on Friday and I ju…

---

## [High dimensional (stochastic) optimal control](https://discourse.julialang.org/t/high-dimensional-stochastic-optimal-control/137345)

<div class="topic-metadata">

**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 5\
**Last updated:** [May 31, 2026, 11:10pm UTC](https://discourse.julialang.org/t/high-dimensional-stochastic-optimal-control/137345 "2026-05-31T23:10:17Z")

</div>

Dear all, in the context of stochastic control, I am wondering if some of you have implemented either of the two papers in julia. Onken, D., Nurbekyan, L., Li, X., Fung, S. W., Osher, S., & Ruthotto, L. (2023). A Neur…

---

## [Why Dense layer and Chain don't work for calculating gradient?](https://discourse.julialang.org/t/why-dense-layer-and-chain-dont-work-for-calculating-gradient/137360)

<div class="topic-metadata">

**Author:** [@MathJulia](https://discourse.julialang.org/u/MathJulia)\
**Replies:** 0\
**Last updated:** [May 31, 2026, 10:24am UTC](https://discourse.julialang.org/t/why-dense-layer-and-chain-dont-work-for-calculating-gradient/137360 "2026-05-31T10:24:02Z")

</div>

I worked with Julia for 5 years. Flux.jl gradient worked correctly. but in new versions I receive this error. Chain(Dense…, …) I see this error. \*\*MethodError: no method matching l(::Chain{Tuple{Dense{typeof(relu), Mat…

---

## [Strategy for debugging heisenbug involving CSV and DuckDB?](https://discourse.julialang.org/t/strategy-for-debugging-heisenbug-involving-csv-and-duckdb/137359)

<div class="topic-metadata">

**Author:** [@paulmelis](https://discourse.julialang.org/u/paulmelis)\
**Replies:** 3\
**Last updated:** [May 31, 2026, 10:03am UTC](https://discourse.julialang.org/t/strategy-for-debugging-heisenbug-involving-csv-and-duckdb/137359 "2026-05-31T10:03:47Z")

</div>

I’ve been trying to come to grips with some very weird behaviour when using CSV.jl and DuckDB.jl in the same script. Basically I want to parse some large CSV files and store their data in a DuckDB database file using the…

---

## [Documenter: callable objects](https://discourse.julialang.org/t/documenter-callable-objects/36239)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 3\
**Last updated:** [May 30, 2026, 4:19pm UTC](https://discourse.julialang.org/t/documenter-callable-objects/36239 "2026-05-30T16:19:46Z")

</div>

Is it possible to document a callable object “call” definition? Documenter complains about documentation not found. This is the code location: (MeshCore.jl/increl.jl at 80229d26e7a7e4a821b04df2815604101e595375 · PetrKry…

---

## [About(xxx) dies with missing face!()](https://discourse.julialang.org/t/about-xxx-dies-with-missing-face/136854)

<div class="topic-metadata">

**Author:** [@devel-chm](https://discourse.julialang.org/u/devel-chm)\
**Replies:** 3\
**Last updated:** [May 30, 2026, 3:19am UTC](https://discourse.julialang.org/t/about-xxx-dies-with-missing-face/136854 "2026-05-30T03:19:08Z")

</div>

This is on julia 1.10.9 on windows 11: julia\> about(a3) Makie.Axis (mutable) (\<: Makie.AbstractAxis \<: Makie.Block \<: Any), occupies 1.2kB directly (referencing 27MB in total) parent::Union{Nothing, Figure…

---

## [A kind of "two language problem" in Julia Ecosystem](https://discourse.julialang.org/t/a-kind-of-two-language-problem-in-julia-ecosystem/100445)

<div class="topic-metadata">

**Author:** [@algunion](https://discourse.julialang.org/u/algunion)\
**Replies:** 53\
**Last updated:** [May 30, 2026, 2:58am UTC](https://discourse.julialang.org/t/a-kind-of-two-language-problem-in-julia-ecosystem/100445 "2026-05-30T02:58:56Z")

</div>

I am learning a lot these days by reading the source code of various Julia packages. There are certain scenarios where I see certain things achieved in some packages - things that don’t seem to be documented anywhere. I…

---

## [HTTP Streaming Antropic Claude AI](https://discourse.julialang.org/t/http-streaming-antropic-claude-ai/117666)

<div class="topic-metadata">

**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 8\
**Last updated:** [May 29, 2026, 10:14pm UTC](https://discourse.julialang.org/t/http-streaming-antropic-claude-ai/117666 "2026-05-29T22:14:01Z")

</div>

Hey Julianners, Yesterday I stucked with the HTTP streaming functionality very well and just cannot figure out how to solve it. I suppose the problem is with the body in the POST message. Also I cannot do write(response…

---

## [Avoid \`-\` in \`@sprintf("%.1f", -0.001)\`](https://discourse.julialang.org/t/avoid-in-sprintf-1f-0-001/137334)

<div class="topic-metadata">

**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 4\
**Last updated:** [May 29, 2026, 8:00pm UTC](https://discourse.julialang.org/t/avoid-in-sprintf-1f-0-001/137334 "2026-05-29T20:00:44Z")

</div>

The title says it all, but generally I want to avoid a negative number that is rounded to all-zeros by printf to have a -. julia\> using Printf julia\> @sprintf("%.1f", -0.001) "-0.0" ▶ see a truly horrid solution here

[Previous page](https://discourse.julialang.org/c/usage/6.md?page=7)

[Next page](https://discourse.julialang.org/c/usage/6.md?page=9)