# Latest

**URL:** https://discourse.julialang.org/latest.md?page=301

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

**Page:** 302

---

## [Can I consider variables as Float32 or Float16 in JuMP](https://discourse.julialang.org/t/can-i-consider-variables-as-float32-or-float16-in-jump/121216)

<div class="topic-metadata">

**Author:** [@Anassis\_b](https://discourse.julialang.org/u/Anassis_b)\
**Replies:** 2\
**Last updated:** [October 12, 2024, 10:00pm UTC](https://discourse.julialang.org/t/can-i-consider-variables-as-float32-or-float16-in-jump/121216 "2024-10-12T22:00:45Z")

</div>

Hi all, I’m working on an optimization problem using JuMP with IPOPT, and I noticed that by default, variables are declared as Float64. I would like to explore using Float32 and Float16 for my variables instead. Additio…

---

## [Can LinearSolve.jl be used for non-square matrices?](https://discourse.julialang.org/t/can-linearsolve-jl-be-used-for-non-square-matrices/121217)

<div class="topic-metadata">

**Author:** [@l8l](https://discourse.julialang.org/u/l8l)\
**Replies:** 4\
**Last updated:** [October 12, 2024, 7:19pm UTC](https://discourse.julialang.org/t/can-linearsolve-jl-be-used-for-non-square-matrices/121217 "2024-10-12T19:19:07Z")

</div>

This might be a naive question, and the title basically says it already: I am trying to use LinearSolve.jl but get an error for non-square matrices: Assume I have matrix A of dimension n\\times p and vector b of dimension…

---

## [Optimize Apache Arrow data streaming over HTTP](https://discourse.julialang.org/t/optimize-apache-arrow-data-streaming-over-http/113692)

<div class="topic-metadata">

**Author:** [@simsurace](https://discourse.julialang.org/u/simsurace)\
**Replies:** 29\
**Last updated:** [October 12, 2024, 6:56pm UTC](https://discourse.julialang.org/t/optimize-apache-arrow-data-streaming-over-http/113692 "2024-10-12T18:56:55Z")

</div>

Following a request on the Arrow.jl project, I started implementing a simple Julia example here. With the exeption of an upstream issue on macOS, it seems to work. However, the implementation seems to be less performant …

---

## [Performance of derivatives of Ensemble problem](https://discourse.julialang.org/t/performance-of-derivatives-of-ensemble-problem/121167)

<div class="topic-metadata">

**Author:** [@stochasticguy](https://discourse.julialang.org/u/stochasticguy)\
**Replies:** 2\
**Last updated:** [October 12, 2024, 6:34pm UTC](https://discourse.julialang.org/t/performance-of-derivatives-of-ensemble-problem/121167 "2024-10-12T18:34:29Z")

</div>

Hi everyone, I’m working on simulating trajectories of a Geometric Brownian Motion (GBM) and calculating sensitivities using automatic differentiation. I’m comparing two approaches: Custom GBM implementation where I d…

---

## [Bouncing Ball Example](https://discourse.julialang.org/t/bouncing-ball-example/121148)

<div class="topic-metadata">

**Author:** [@Muhammad\_Arsal](https://discourse.julialang.org/u/Muhammad_Arsal)\
**Replies:** 10\
**Last updated:** [October 12, 2024, 6:03pm UTC](https://discourse.julialang.org/t/bouncing-ball-example/121148 "2024-10-12T18:03:09Z")

</div>

has anyone tried bouncing ball example form the predefined examples? It does not run well enough for me. Any help???

---

## [Pre-allocating array efficiency](https://discourse.julialang.org/t/pre-allocating-array-efficiency/121207)

<div class="topic-metadata">

**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 5\
**Last updated:** [October 12, 2024, 4:52pm UTC](https://discourse.julialang.org/t/pre-allocating-array-efficiency/121207 "2024-10-12T16:52:22Z")

</div>

Hi there, my understanding was, in vague terms, that pre-allocating an array by specifying size and then populating the elements of that array was more efficient than defining an array without doing so. To test this I j…

---

## [Why does Julia need an administrator account to run?](https://discourse.julialang.org/t/why-does-julia-need-an-administrator-account-to-run/121201)

<div class="topic-metadata">

**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 4\
**Last updated:** [October 12, 2024, 4:15pm UTC](https://discourse.julialang.org/t/why-does-julia-need-an-administrator-account-to-run/121201 "2024-10-12T16:15:37Z")

</div>

Hello, I installed Julia on a computer that is a member of a Windows domain network, but it requires an administrator account to run. Why? Thank you.

---

## [Error by \`append(a::Vector{T}, b::Vector{T})::Vector{T} where T = vcat(a, b)\`](https://discourse.julialang.org/t/error-by-append-a-vector-t-b-vector-t-vector-t-where-t-vcat-a-b/121226)

<div class="topic-metadata">

**Author:** [@paalon](https://discourse.julialang.org/u/paalon)\
**Replies:** 1\
**Last updated:** [October 12, 2024, 3:52pm UTC](https://discourse.julialang.org/t/error-by-append-a-vector-t-b-vector-t-vector-t-where-t-vcat-a-b/121226 "2024-10-12T15:52:01Z")

</div>

The following shorter function definition gives the error but the longer definition doesn’t: julia\> append(a::Vector{T}, b::Vector{T})::Vector{T} where T = vcat(a, b) ERROR: UndefVarError: \`T\` not defined in \`Main\` Sugg…

---

## [Creating a Docker Base Image for Faster Deployments](https://discourse.julialang.org/t/creating-a-docker-base-image-for-faster-deployments/121165)

<div class="topic-metadata">

**Author:** [@mrufsvold](https://discourse.julialang.org/u/mrufsvold)\
**Replies:** 1\
**Last updated:** [October 11, 2024, 8:27am UTC](https://discourse.julialang.org/t/creating-a-docker-base-image-for-faster-deployments/121165 "2024-10-11T08:27:58Z")

</div>

In my experience, deploying Julia to the cloud can be frustrating because it can be slow to build the container used to your app. I don’t seem to be the only one. A major gripe is that AWS CodeBuild can’t do layer cachin…

---

## [Put linear ODE system in matrix-vector form](https://discourse.julialang.org/t/put-linear-ode-system-in-matrix-vector-form/121170)

<div class="topic-metadata">

**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 5\
**Last updated:** [October 12, 2024, 1:51pm UTC](https://discourse.julialang.org/t/put-linear-ode-system-in-matrix-vector-form/121170 "2024-10-12T13:51:51Z")

</div>

Hi, I am trying to put my linear ODE system in state space form. My model is quite simple: function TiThTe(input\_funcs::Dict) @parameters begin C\_i C\_e C\_h R\_ie R\_ih …

---

## [Unexpected(?) behavior using ModelingToolkit.jl, discrete\_events and irreducible](https://discourse.julialang.org/t/unexpected-behavior-using-modelingtoolkit-jl-discrete-events-and-irreducible/121142)

<div class="topic-metadata">

**Author:** [@jmaedler](https://discourse.julialang.org/u/jmaedler)\
**Replies:** 2\
**Last updated:** [October 12, 2024, 1:40pm UTC](https://discourse.julialang.org/t/unexpected-behavior-using-modelingtoolkit-jl-discrete-events-and-irreducible/121142 "2024-10-12T13:40:24Z")

</div>

Hi everyone, I am running into an issues using discrete events and irreducible variables in ModelingToolkit.jl. I hope the following example is sufficent as an MWE. It is a composite model of two tanks in sequence which…

---

## [Spambots trolling Julia Discourse!](https://discourse.julialang.org/t/spambots-trolling-julia-discourse/121205)

<div class="topic-metadata">

**Author:** [@PeterSimon](https://discourse.julialang.org/u/PeterSimon)\
**Replies:** 5\
**Last updated:** [October 12, 2024, 12:10pm UTC](https://discourse.julialang.org/t/spambots-trolling-julia-discourse/121205 "2024-10-12T12:10:33Z")

</div>

I posted an announcement for a new package yesterday. When I checked my email this morning, I found two replies routed from Discourse. Apparently, only one of these was legitimate. The other appears to be AI-generated…

---

## [Julia VS Code debugger crash](https://discourse.julialang.org/t/julia-vs-code-debugger-crash/120867)

<div class="topic-metadata">

**Author:** [@l8l](https://discourse.julialang.org/u/l8l)\
**Replies:** 13\
**Last updated:** [October 12, 2024, 10:16am UTC](https://discourse.julialang.org/t/julia-vs-code-debugger-crash/120867 "2024-10-12T10:16:42Z")

</div>

I am trying to debug code in the julia vscode debugger. Usually all goes well but when setting a breakpoint inside a function, that is called by an imported library, the debugger crashes when trying to display the variab…

---

## [A simple development environment for Julia](https://discourse.julialang.org/t/a-simple-development-environment-for-julia/120969)

<div class="topic-metadata">

**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 20\
**Last updated:** [October 12, 2024, 9:30am UTC](https://discourse.julialang.org/t/a-simple-development-environment-for-julia/120969 "2024-10-12T09:30:19Z")

</div>

Hello, I’m sure Julia’s team knows that one of the secrets of a successful project is having a good graphical environment. I looked at a few Julia GUIs as a hobbyist, but they didn’t really fit. I think an environment l…

---

## [\[ANN\] NeuroTreeModels.jl - Differentiable tree-based models for tabular data](https://discourse.julialang.org/t/ann-neurotreemodels-jl-differentiable-tree-based-models-for-tabular-data/110707)

<div class="topic-metadata">

**Author:** [@jeremiedb](https://discourse.julialang.org/u/jeremiedb)\
**Replies:** 6\
**Last updated:** [October 12, 2024, 7:05am UTC](https://discourse.julialang.org/t/ann-neurotreemodels-jl-differentiable-tree-based-models-for-tabular-data/110707 "2024-10-12T07:05:48Z")

</div>

Announcement for the initial release of NeuroTreeModels.jl NeuroTree based models comprise a collection of differentiable trees, in an attempt get both the performance benefits of boosted tree methods and flexibility of…

---

## [~TidierData.jl~ - Apply Transform to Many Columns](https://discourse.julialang.org/t/tidierdata-jl-apply-transform-to-many-columns/120726)

<div class="topic-metadata">

**Author:** [@mrufsvold](https://discourse.julialang.org/u/mrufsvold)\
**Replies:** 4\
**Last updated:** [October 12, 2024, 4:12am UTC](https://discourse.julialang.org/t/tidierdata-jl-apply-transform-to-many-columns/120726 "2024-10-12T04:12:29Z")

</div>

I have a dataset with a bunch of columns with string data that have the format “(1.0, 2.0)”. All of these columns end with the postfix “CI”. I’d like to apply a function that splits the numbers into the low and high valu…

---

## [Makie observable lift functions](https://discourse.julialang.org/t/makie-observable-lift-functions/121202)

<div class="topic-metadata">

**Author:** [@Andy2K11](https://discourse.julialang.org/u/Andy2K11)\
**Replies:** 5\
**Last updated:** [October 12, 2024, 6:37am UTC](https://discourse.julialang.org/t/makie-observable-lift-functions/121202 "2024-10-12T06:37:57Z")

</div>

Hi. I’ve been trying to learn how to use observables in Makie and have managed to make an interactive plot with an IntervalSlider. The xaxis ticks are controlled with a lift function: xticks = lift(ab\_slider.inte…

---

## [Nice way to iterate through a triangular matrix](https://discourse.julialang.org/t/nice-way-to-iterate-through-a-triangular-matrix/101667)

<div class="topic-metadata">

**Author:** [@RobertGregg](https://discourse.julialang.org/u/RobertGregg)\
**Replies:** 10\
**Last updated:** [October 12, 2024, 5:32am UTC](https://discourse.julialang.org/t/nice-way-to-iterate-through-a-triangular-matrix/101667 "2024-10-12T05:32:38Z")

</div>

I often need to loop through the upper/lower triangular section of a matrix and usually end up doing something like: A = reshape(1:25,5,5) for j in axes(A,2) for i in axes(A,1) if i\>j @show A\[i,…

---

## [OOP-like dot notation in Julia](https://discourse.julialang.org/t/oop-like-dot-notation-in-julia/120971)

<div class="topic-metadata">

**Author:** [@Barget](https://discourse.julialang.org/u/Barget)\
**Replies:** 44\
**Last updated:** [October 12, 2024, 5:08am UTC](https://discourse.julialang.org/t/oop-like-dot-notation-in-julia/120971 "2024-10-12T05:08:53Z")

</div>

This is a naive question, but given the widespread use of the object.method notation in OOP languages, I struggle to find a sound reason as of why it can’t (or shouldn’t) be supported in Julia? I assumes this has somethi…

---

## [How to clear a plot from a scene with other elements in GLMakie](https://discourse.julialang.org/t/how-to-clear-a-plot-from-a-scene-with-other-elements-in-glmakie/121164)

<div class="topic-metadata">

**Author:** [@Emerson\_Vitor\_Castel](https://discourse.julialang.org/u/Emerson_Vitor_Castel)\
**Replies:** 4\
**Last updated:** [October 12, 2024, 1:09am UTC](https://discourse.julialang.org/t/how-to-clear-a-plot-from-a-scene-with-other-elements-in-glmakie/121164 "2024-10-12T01:09:01Z")

</div>

Well, I’m new to using GLMakie. I wrote a script where I want to capture mouse events and plot the points using the scatter! function. In this same scene, I would like to insert a button with the ability to clear the poi…

---

## [\[ANN\] ECLGraphColor: graph coloring in parallel](https://discourse.julialang.org/t/ann-eclgraphcolor-graph-coloring-in-parallel/114077)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [October 12, 2024, 12:11am UTC](https://discourse.julialang.org/t/ann-eclgraphcolor-graph-coloring-in-parallel/114077 "2024-10-12T00:11:06Z")

</div>

A sophisticated algorithm implemented in an OpenMP library is wrapped in a thin layer. I use it for finite element mesh coloring.

---

## [Unable to reinstall release channel with Juliaup](https://discourse.julialang.org/t/unable-to-reinstall-release-channel-with-juliaup/121210)

<div class="topic-metadata">

**Author:** [@ElMissas](https://discourse.julialang.org/u/ElMissas)\
**Replies:** 1\
**Last updated:** [October 11, 2024, 11:47pm UTC](https://discourse.julialang.org/t/unable-to-reinstall-release-channel-with-juliaup/121210 "2024-10-11T23:47:14Z")

</div>

I was using Julia 1.10 in the release channel, and I updated it to 1.11. However, this version was giving me some problems with precompiling packages, so I wanted to downgrade to 1.10. I used juliaup add 1.10 to add the…

---

## [Odd behaviour regarding Adjoint Sensitivity Analysis](https://discourse.julialang.org/t/odd-behaviour-regarding-adjoint-sensitivity-analysis/121141)

<div class="topic-metadata">

**Author:** [@nil](https://discourse.julialang.org/u/nil)\
**Replies:** 8\
**Last updated:** [October 11, 2024, 9:49pm UTC](https://discourse.julialang.org/t/odd-behaviour-regarding-adjoint-sensitivity-analysis/121141 "2024-10-11T21:49:13Z")

</div>

Hello dear community, I have a question regarding the following code I have written. I am trying to calculate the adjoint of the simple (linear) systems forward simulation with respect to the input u. using LinearAlgeb…

---

## [Flux - sigmoid in last layer destroys learning?](https://discourse.julialang.org/t/flux-sigmoid-in-last-layer-destroys-learning/121174)

<div class="topic-metadata">

**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 13\
**Last updated:** [October 11, 2024, 3:12pm UTC](https://discourse.julialang.org/t/flux-sigmoid-in-last-layer-destroys-learning/121174 "2024-10-11T15:12:18Z")

</div>

I’m fairly new to ML. But my understanding is that inner layers should generally use relu, and the final layer should use whatever function constrains the output to the range you want. In my case, sigmoid to constrain be…

---

## [Local Error Estimation for DAEs](https://discourse.julialang.org/t/local-error-estimation-for-daes/121159)

<div class="topic-metadata">

**Author:** [@aaliqureshi](https://discourse.julialang.org/u/aaliqureshi)\
**Replies:** 7\
**Last updated:** [October 11, 2024, 3:09pm UTC](https://discourse.julialang.org/t/local-error-estimation-for-daes/121159 "2024-10-11T15:09:15Z")

</div>

I’m inquiring about the error estimation approach used for solving Differential Algebraic Equations (DAEs) in Julia. The current approach considers all variables (state and algebraic) in the estimation of local error. H…

---

## [Julia seminar: sign up online](https://discourse.julialang.org/t/julia-seminar-sign-up-online/121171)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [October 11, 2024, 2:50pm UTC](https://discourse.julialang.org/t/julia-seminar-sign-up-online/121171 "2024-10-11T14:50:48Z")

</div>

ACES: Introduction to Julia | ACCESS Support (access-ci.org) Self-explanatory, I think.

---

## [\`Base.Docs.doc\` failing with 1.11.0](https://discourse.julialang.org/t/base-docs-doc-failing-with-1-11-0/121187)

<div class="topic-metadata">

**Author:** [@sstroemer](https://discourse.julialang.org/u/sstroemer)\
**Replies:** 3\
**Last updated:** [October 11, 2024, 2:09pm UTC](https://discourse.julialang.org/t/base-docs-doc-failing-with-1-11-0/121187 "2024-10-11T14:09:02Z")

</div>

We are using the following function to modify docstrings of some of our types to “dynamically” add information: function \_finalize\_docstring(datatype::Type) binding = Base.Docs.aliasof(datatype, typeof(datatype)) …

---

## [How to do sparse row vector\*matrix?](https://discourse.julialang.org/t/how-to-do-sparse-row-vector-matrix/121166)

<div class="topic-metadata">

**Author:** [@happyxie](https://discourse.julialang.org/u/happyxie)\
**Replies:** 3\
**Last updated:** [October 11, 2024, 1:43pm UTC](https://discourse.julialang.org/t/how-to-do-sparse-row-vector-matrix/121166 "2024-10-11T13:43:41Z")

</div>

I am trying to do a row vector times a matrix but it give an adjoint type instead of a row vector? should I do (A’A\[1,:\])'? I need the results to be a vector so I can continue other calculation. Thanks. A=sparse(\[1 2;3…

---

## [Startup.jl being replaced constantly](https://discourse.julialang.org/t/startup-jl-being-replaced-constantly/121185)

<div class="topic-metadata">

**Author:** [@Gilham](https://discourse.julialang.org/u/Gilham)\
**Replies:** 2\
**Last updated:** [October 11, 2024, 12:52pm UTC](https://discourse.julialang.org/t/startup-jl-being-replaced-constantly/121185 "2024-10-11T12:52:18Z")

</div>

Hi Guys, Im hoping you could assist with an issue im having, I work at a university and I have never used Julia before so im getting a little lost. We have Julia installed for students and we had a request to have a sh…

---

## [Startup.jl errors in 1.11.0](https://discourse.julialang.org/t/startup-jl-errors-in-1-11-0/121193)

<div class="topic-metadata">

**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 1\
**Last updated:** [October 11, 2024, 12:43pm UTC](https://discourse.julialang.org/t/startup-jl-errors-in-1-11-0/121193 "2024-10-11T12:43:13Z")

</div>

My startup.jl file errors in Julia 1.11.0 and not in 1.10. atreplinit() do repl @eval begin using Revise using OhMyREPL using BenchmarkTools using Infiltrator end end with the message jakez@raspberrypi:~/dat…

[Previous page](https://discourse.julialang.org/latest.md?page=300)

[Next page](https://discourse.julialang.org/latest.md?page=302)