# Latest

**URL:** https://discourse.julialang.org/latest.md?page=621

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

**Page:** 622

---

## [JuliaData BoF @ JuliaCon2023 discussion](https://discourse.julialang.org/t/juliadata-bof-juliacon2023-discussion/102521)

<div class="topic-metadata">

**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 2\
**Last updated:** [August 14, 2023, 2:05am UTC](https://discourse.julialang.org/t/juliadata-bof-juliacon2023-discussion/102521 "2023-08-14T02:05:10Z")

</div>

Below I recap a summary from the BoF Data Ecosystem discussion during JuliaCon2023 (for sure, it is probably opinionated, so feel free to comment to add your thoughts). I recap things I took out as most important to wor…

---

## [\[ANN\] DICOMTree.jl](https://discourse.julialang.org/t/ann-dicomtree-jl/102777)

<div class="topic-metadata">

**Author:** [@fdekerme](https://discourse.julialang.org/u/fdekerme)\
**Replies:** 0\
**Last updated:** [August 13, 2023, 10:14pm UTC](https://discourse.julialang.org/t/ann-dicomtree-jl/102777 "2023-08-13T22:14:15Z")

</div>

Hello everyone! :grin: I’m pleased to announce my first (small) contribution to the Julia ecosystem. I’m talking about the DICOMTree.jl package, which enables DICOM medical files to be visualized simply and clearly in t…

---

## [How to properly work with changing precision in ArbNumerics](https://discourse.julialang.org/t/how-to-properly-work-with-changing-precision-in-arbnumerics/102775)

<div class="topic-metadata">

**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 2\
**Last updated:** [August 13, 2023, 9:03pm UTC](https://discourse.julialang.org/t/how-to-properly-work-with-changing-precision-in-arbnumerics/102775 "2023-08-13T21:03:17Z")

</div>

I do not understand how I should properly work with ArbNumerics. I tried setting the number of digits at the beginning of my code, so that later I easily change the number of digits for all of my variables. digits = 20…

---

## [Type-unstable application of \`map\`](https://discourse.julialang.org/t/type-unstable-application-of-map/102771)

<div class="topic-metadata">

**Author:** [@ffevotte](https://discourse.julialang.org/u/ffevotte)\
**Replies:** 4\
**Last updated:** [August 13, 2023, 8:17pm UTC](https://discourse.julialang.org/t/type-unstable-application-of-map/102771 "2023-08-13T20:17:34Z")

</div>

Consider the following (minimal?) example: julia\> struct A{N} A(::NTuple{N,Int}) where {N} = new{N}() end julia\> t = (1,2) (1, 2) julia\> T = typeof(t) Tuple{Int64, Int64} julia\> using Test julia\> @…

---

## [Multi-threaded calls to CUDA matrix multiplication](https://discourse.julialang.org/t/multi-threaded-calls-to-cuda-matrix-multiplication/102753)

<div class="topic-metadata">

**Author:** [@eveningsilverfox](https://discourse.julialang.org/u/eveningsilverfox)\
**Replies:** 5\
**Last updated:** [August 13, 2023, 5:58pm UTC](https://discourse.julialang.org/t/multi-threaded-calls-to-cuda-matrix-multiplication/102753 "2023-08-13T17:58:04Z")

</div>

I am trying to call CUDA matrix multiplication using a multi-threaded for loop, but I am getting an error (Initialising Julia with julia -t8). My cpu has 8 cores (16 threads), and my GPU is NVIDIA GeForce GTX 1650 with 1…

---

## [Create a (Di)graph from an iterator over edges with a certain number of vertices](https://discourse.julialang.org/t/create-a-di-graph-from-an-iterator-over-edges-with-a-certain-number-of-vertices/102751)

<div class="topic-metadata">

**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 2\
**Last updated:** [August 13, 2023, 3:20pm UTC](https://discourse.julialang.org/t/create-a-di-graph-from-an-iterator-over-edges-with-a-certain-number-of-vertices/102751 "2023-08-13T15:20:02Z")

</div>

Given that I have a set of edges, e.g: using Graphs g = Graphs.grid(\[5, 5\]) es = edges(g) How do I create a new Graph, using those edges, but wit ha specific number of vertices? In this case I can do: SimpleDiGraphFro…

---

## [Could not spawn setenv error](https://discourse.julialang.org/t/could-not-spawn-setenv-error/102734)

<div class="topic-metadata">

**Author:** [@dogtired](https://discourse.julialang.org/u/dogtired)\
**Replies:** 6\
**Last updated:** [August 13, 2023, 12:22pm UTC](https://discourse.julialang.org/t/could-not-spawn-setenv-error/102734 "2023-08-13T12:22:20Z")

</div>

I have installed Julia 1.9 on a POP OS system with i9-139000HX processor and am getting this error: Activating project at ~/.vscode/extensions/julialang.language-julia-1.47.2/scripts/environments/languageserver/v1.9 \[ …

---

## [\[ANN\] Announcing HOODESolver.jl](https://discourse.julialang.org/t/ann-announcing-hoodesolver-jl/52126)

<div class="topic-metadata">

**Author:** [@pnavaro](https://discourse.julialang.org/u/pnavaro)\
**Replies:** 10\
**Last updated:** [August 13, 2023, 11:27am UTC](https://discourse.julialang.org/t/ann-announcing-hoodesolver-jl/52126 "2023-08-13T11:27:51Z")

</div>

Dear all, HOODESolver.jl is a julia package to solve numerically highly-oscillatory ODE problems. The package is mainly developed by @ymocquar. It implements Uniformly Accurate numerical methods (UA) and works with Big …

---

## [Accessing the category of a Char](https://discourse.julialang.org/t/accessing-the-category-of-a-char/102745)

<div class="topic-metadata">

**Author:** [@ultradian](https://discourse.julialang.org/u/ultradian)\
**Replies:** 4\
**Last updated:** [August 13, 2023, 11:05am UTC](https://discourse.julialang.org/t/accessing-the-category-of-a-char/102745 "2023-08-13T11:05:41Z")

</div>

I was playing around and just noticed that there is a category for every Char. For example: julia\> Char(‘a’) ‘a’: ASCII/Unicode U+0061 (category Ll: Letter, lowercase) julia\> Char(‘?’) ‘?’: ASCII/Unicode U+003F (cat…

---

## [Converting between interactive and non-interactive soft scope code](https://discourse.julialang.org/t/converting-between-interactive-and-non-interactive-soft-scope-code/102754)

<div class="topic-metadata">

**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 0\
**Last updated:** [August 12, 2023, 9:34pm UTC](https://discourse.julialang.org/t/converting-between-interactive-and-non-interactive-soft-scope-code/102754 "2023-08-12T21:34:50Z")

</div>

Never was a fan of some local scopes being made “soft”, meaning reassigning global variables without declarations in interactive contexts (REPL, notebooks) instead of making a local variable; for example, for \_ in 1 s=0 …

---

## [\`tail\` for Vector](https://discourse.julialang.org/t/tail-for-vector/102758)

<div class="topic-metadata">

**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 2\
**Last updated:** [August 13, 2023, 2:27am UTC](https://discourse.julialang.org/t/tail-for-vector/102758 "2023-08-13T02:27:54Z")

</div>

tail is only implemented on Tuple. If it were also for Vector, should it be a copy or a view?

---

## [UndefVarError: \`ComponentArray\` not defined when using GPU in NeuralPDE](https://discourse.julialang.org/t/undefvarerror-componentarray-not-defined-when-using-gpu-in-neuralpde/102725)

<div class="topic-metadata">

**Author:** [@Ethan\_Tran](https://discourse.julialang.org/u/Ethan_Tran)\
**Replies:** 9\
**Last updated:** [August 13, 2023, 12:23am UTC](https://discourse.julialang.org/t/undefvarerror-componentarray-not-defined-when-using-gpu-in-neuralpde/102725 "2023-08-13T00:23:14Z")

</div>

I tried to run NeuralPDE with GPU by the tutorial code in NeuralPDE.jl as follows: using NeuralPDE, Lux, CUDA, Random using Optimization using OptimizationOptimisers import ModelingToolkit: Interval @parameters t x y @…

---

## [Displaying images with text](https://discourse.julialang.org/t/displaying-images-with-text/102694)

<div class="topic-metadata">

**Author:** [@cpfiffer](https://discourse.julialang.org/u/cpfiffer)\
**Replies:** 16\
**Last updated:** [August 12, 2023, 11:35pm UTC](https://discourse.julialang.org/t/displaying-images-with-text/102694 "2023-08-12T23:35:22Z")

</div>

I’m working on adapting the fast.ai fastbook with a few other people. You can find our work slowly happening via our website or by the Quarto book here. As part of this, I want to build a little tool to view images with…

---

## [Eval from macro](https://discourse.julialang.org/t/eval-from-macro/102718)

<div class="topic-metadata">

**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 4\
**Last updated:** [August 12, 2023, 9:24pm UTC](https://discourse.julialang.org/t/eval-from-macro/102718 "2023-08-12T21:24:31Z")

</div>

Hi, Here is some code: module mypack export @my\_eval macro my\_eval(pkg) pp = pkg |\> string eval(Meta.parse(string("using ", pp))) end end @my\_eval CSV In the code above, I am trying to use a macro to achie…

---

## [Reading LIBSVM format](https://discourse.julialang.org/t/reading-libsvm-format/99466)

<div class="topic-metadata">

**Author:** [@ymalitsky](https://discourse.julialang.org/u/ymalitsky)\
**Replies:** 3\
**Last updated:** [August 12, 2023, 6:59pm UTC](https://discourse.julialang.org/t/reading-libsvm-format/99466 "2023-08-12T18:59:30Z")

</div>

Hi! How one can read files in the libsvm format in Julia? The LIBSVM.jl package seems to implement only algorithms. My current solution would be to read the file in python, save it in other format and then load it into J…

---

## [Generate sub-tuples in an efficient, type-stable way](https://discourse.julialang.org/t/generate-sub-tuples-in-an-efficient-type-stable-way/102750)

<div class="topic-metadata">

**Author:** [@ffevotte](https://discourse.julialang.org/u/ffevotte)\
**Replies:** 2\
**Last updated:** [August 12, 2023, 5:56pm UTC](https://discourse.julialang.org/t/generate-sub-tuples-in-an-efficient-type-stable-way/102750 "2023-08-12T17:56:14Z")

</div>

Given a NTuple{N, T}, I’d like to generate the collection of all sub-tuples that can be obtained by removing one element from the original tuple. This collection of sub-tuples can be represented as an NTuple{N, NTuple{N-…

---

## [Workflow challenges with redefining structs (from "Why I still recommend Julia")](https://discourse.julialang.org/t/workflow-challenges-with-redefining-structs-from-why-i-still-recommend-julia/83593)

<div class="topic-metadata">

**Author:** [@sairus7](https://discourse.julialang.org/u/sairus7)\
**Replies:** 22\
**Last updated:** [August 12, 2023, 5:33pm UTC](https://discourse.julialang.org/t/workflow-challenges-with-redefining-structs-from-why-i-still-recommend-julia/83593 "2023-08-12T17:33:38Z")

</div>

"Hence, the development workflow is to start the process, get a cup of coffee while it loads for the first time and keep the process alive for the rest of the day". – Or take another cup of coffee each time you change s…

---

## [Cannot execute Julia 1.9.2 binary on NixOS](https://discourse.julialang.org/t/cannot-execute-julia-1-9-2-binary-on-nixos/102748)

<div class="topic-metadata">

**Author:** [@loonatick-src](https://discourse.julialang.org/u/loonatick-src)\
**Replies:** 2\
**Last updated:** [August 12, 2023, 5:30pm UTC](https://discourse.julialang.org/t/cannot-execute-julia-1-9-2-binary-on-nixos/102748 "2023-08-12T17:30:36Z")

</div>

(cross-posted from unix.stackexchange) This is most likely a NixOS-specific issue. I downloaded the Julia 1.9.2 (Linux, x86-64, glibc) prebuilt binary and tried to execute the binary, but I get the following error. bas…

---

## [Simple approachable example highlighting the usage of a stiff ODE solver in DiffEq](https://discourse.julialang.org/t/simple-approachable-example-highlighting-the-usage-of-a-stiff-ode-solver-in-diffeq/102741)

<div class="topic-metadata">

**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 8\
**Last updated:** [August 12, 2023, 5:15pm UTC](https://discourse.julialang.org/t/simple-approachable-example-highlighting-the-usage-of-a-stiff-ode-solver-in-diffeq/102741 "2023-08-12T17:15:13Z")

</div>

Hi all, I will be presenting a Julia tutorial on an international PHD school, and OrdinaryDiffEq.jl will be one of the packages I will be highlighting. I want to demonstrate some of the various solvers of the ecosystem v…

---

## [Plotting pane in VSCdoe is empty](https://discourse.julialang.org/t/plotting-pane-in-vscdoe-is-empty/102737)

<div class="topic-metadata">

**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 1\
**Last updated:** [August 12, 2023, 3:43pm UTC](https://discourse.julialang.org/t/plotting-pane-in-vscdoe-is-empty/102737 "2023-08-12T15:43:44Z")

</div>

Plotting in VSCode has suddenly stopped working, I do not really know why. If I try: using Plots plot(x-\>x) The plotting pane shows up (and shows the right figure number), but is empty: I have tried restarting Jul…

---

## [Lighter alternatives to a dataframe when you just want to run a few queries on a vector of data structs](https://discourse.julialang.org/t/lighter-alternatives-to-a-dataframe-when-you-just-want-to-run-a-few-queries-on-a-vector-of-data-structs/102510)

<div class="topic-metadata">

**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 31\
**Last updated:** [August 12, 2023, 3:05pm UTC](https://discourse.julialang.org/t/lighter-alternatives-to-a-dataframe-when-you-just-want-to-run-a-few-queries-on-a-vector-of-data-structs/102510 "2023-08-12T15:05:50Z")

</div>

Lately, I have been running into a lot of tasks where I generate a big long vector of instances of some kind of data struct: julia\> struct Foo; a::Int; b::Int; end julia\> foos = \[Foo(rand(1:4), rand(1:4)) for \_ in 1:10…

---

## [Problem with small integrals](https://discourse.julialang.org/t/problem-with-small-integrals/101634)

<div class="topic-metadata">

**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 19\
**Last updated:** [August 12, 2023, 12:39pm UTC](https://discourse.julialang.org/t/problem-with-small-integrals/101634 "2023-08-12T12:39:02Z")

</div>

I am computing 2 integrals over the real line using quadgk from the package of the same name. The goal is to estimate the ratio of the integrals. Often both integrals are quite small, especially in some extreme cases I’…

---

## [Help to extend the model in Metalhead.jl](https://discourse.julialang.org/t/help-to-extend-the-model-in-metalhead-jl/102742)

<div class="topic-metadata">

**Author:** [@yeruo](https://discourse.julialang.org/u/yeruo)\
**Replies:** 5\
**Last updated:** [August 12, 2023, 10:17am UTC](https://discourse.julialang.org/t/help-to-extend-the-model-in-metalhead-jl/102742 "2023-08-12T10:17:48Z")

</div>

I implemented a self-supervised learning algorithm, MAE (Masked Auto Encoder), based on Flux.jl and Metalhead.jl, It seems to work, especially when propagating forward, but during gradient descent, Zygote alerted me that…

---

## [Reference counting and disposables](https://discourse.julialang.org/t/reference-counting-and-disposables/98875)

<div class="topic-metadata">

**Author:** [@stemann](https://discourse.julialang.org/u/stemann)\
**Replies:** 4\
**Last updated:** [August 12, 2023, 8:56am UTC](https://discourse.julialang.org/t/reference-counting-and-disposables/98875 "2023-08-12T08:56:09Z")

</div>

In ResourcePools.jl/pooled\_abstract\_array.jl at feature/multi-threading · IHPSystems/ResourcePools.jl · GitHub, I have two concepts - in addition to pooled resources / pools of resources: Reference counted instances - …

---

## [Lux Neural ODE Example does not work with Metal](https://discourse.julialang.org/t/lux-neural-ode-example-does-not-work-with-metal/102740)

<div class="topic-metadata">

**Author:** [@George\_Stepaniants](https://discourse.julialang.org/u/George_Stepaniants)\
**Replies:** 0\
**Last updated:** [August 12, 2023, 3:06am UTC](https://discourse.julialang.org/t/lux-neural-ode-example-does-not-work-with-metal/102740 "2023-08-12T03:06:15Z")

</div>

I directly copied the Lux example for creating a neural ODE on MNIST: MNIST Classification using NeuralODE - Lux.jl and simply replaced CUDA with Metal to use my Mac M1 GPU. However, just from this single change the cod…

---

## [Read datetime with timezone offset from csv](https://discourse.julialang.org/t/read-datetime-with-timezone-offset-from-csv/102738)

<div class="topic-metadata">

**Author:** [@vtomar](https://discourse.julialang.org/u/vtomar)\
**Replies:** 1\
**Last updated:** [August 11, 2023, 11:46pm UTC](https://discourse.julialang.org/t/read-datetime-with-timezone-offset-from-csv/102738 "2023-08-11T23:46:13Z")

</div>

I have a csv file that contains datetime column where datetime contains timezone offset. for example: 2019-01-11 17:35:00+00:00 How do I correctly specify the datetime format. I am currently specifying the format below…

---

## [Test macro that checks no exception was thrown?](https://discourse.julialang.org/t/test-macro-that-checks-no-exception-was-thrown/41394)

<div class="topic-metadata">

**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 3\
**Last updated:** [August 11, 2023, 10:32pm UTC](https://discourse.julialang.org/t/test-macro-that-checks-no-exception-was-thrown/41394 "2023-08-11T22:32:48Z")

</div>

I want to implement a test that just need to know the function did not throw any exception. There’s @test\_throws but that’s the exact opposite of what I need. Is there anything like that? I could work around by using …

---

## [File Delay in VSCode GUI on HPC](https://discourse.julialang.org/t/file-delay-in-vscode-gui-on-hpc/102730)

<div class="topic-metadata">

**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 1\
**Last updated:** [August 11, 2023, 9:03pm UTC](https://discourse.julialang.org/t/file-delay-in-vscode-gui-on-hpc/102730 "2023-08-11T21:03:56Z")

</div>

Hello, I am running Julia simulations on an HPC that uses slurm. I usually connect and set up my slurm run scripts using the VSCode remove development and all that works fine. I can inspect the stdout and stderr in case…

---

## [Individual ctivation function for each network output](https://discourse.julialang.org/t/individual-ctivation-function-for-each-network-output/102676)

<div class="topic-metadata">

**Author:** [@tommy\_J](https://discourse.julialang.org/u/tommy_J)\
**Replies:** 1\
**Last updated:** [August 11, 2023, 8:38pm UTC](https://discourse.julialang.org/t/individual-ctivation-function-for-each-network-output/102676 "2023-08-11T20:38:19Z")

</div>

Hi, Can I use a different activation function for each output of my network? using Lux net = Chain(Dense(3, 10, tanh), Dense(10, 3, tanh)) I know that output 2 can only be positive, but 1 and 3 can be negative. Is i…

---

## [Unittest for postgresql database](https://discourse.julialang.org/t/unittest-for-postgresql-database/102720)

<div class="topic-metadata">

**Author:** [@cbe](https://discourse.julialang.org/u/cbe)\
**Replies:** 0\
**Last updated:** [August 11, 2023, 3:48pm UTC](https://discourse.julialang.org/t/unittest-for-postgresql-database/102720 "2023-08-11T15:48:17Z")

</div>

Hello, I would like to test a function doing a call to a database, but I want to mock my connection. I want to test that the returned type of my function is correct without actually calling the database. I’m thinking a…

[Previous page](https://discourse.julialang.org/latest.md?page=620)

[Next page](https://discourse.julialang.org/latest.md?page=622)