# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1747

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

**Page:** 1748

---

## [Tiled matrix multiplication](https://discourse.julialang.org/t/tiled-matrix-multiplication/38431)

<div class="topic-metadata">

**Author:** [@Matt\_Davis](https://discourse.julialang.org/u/Matt_Davis)\
**Replies:** 4\
**Last updated:** [May 14, 2020, 3:30am UTC](https://discourse.julialang.org/t/tiled-matrix-multiplication/38431 "2020-05-14T03:30:58Z")

</div>

Hello, I would like to accelerate multiplication of matrices that are larger than can fit in VRAM, but can fit in normal RAM. I would like to eventually extend this to general tensor contractions as well, but for now I …

---

## [Having trouble parallelizing a system of ODEs](https://discourse.julialang.org/t/having-trouble-parallelizing-a-system-of-odes/39442)

<div class="topic-metadata">

**Author:** [@Lachlan-Bn](https://discourse.julialang.org/u/Lachlan-Bn)\
**Replies:** 1\
**Last updated:** [May 14, 2020, 3:28am UTC](https://discourse.julialang.org/t/having-trouble-parallelizing-a-system-of-odes/39442 "2020-05-14T03:28:32Z")

</div>

Allow me to preface this by saying I have limited programming experience beyond the relatively short time I’ve been using Julia, so if you see I’ve made some kind of coding faux pas, please point it out! I have a non-li…

---

## [Trying to better understand how Julia listens on a UNIX domain socket or named pipe](https://discourse.julialang.org/t/trying-to-better-understand-how-julia-listens-on-a-unix-domain-socket-or-named-pipe/39396)

<div class="topic-metadata">

**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 2\
**Last updated:** [May 14, 2020, 2:06am UTC](https://discourse.julialang.org/t/trying-to-better-understand-how-julia-listens-on-a-unix-domain-socket-or-named-pipe/39396 "2020-05-14T02:06:17Z")

</div>

Hi all, I copied the following code from this Discourse response about linking Julia and node.js. I’m very new to the idea of both tasks and sockets, and although I’ve got the code working perfectly for my use-case, I w…

---

## [Missing epsilon](https://discourse.julialang.org/t/missing-epsilon/39430)

<div class="topic-metadata">

**Author:** [@Jul](https://discourse.julialang.org/u/Jul)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 9:21pm UTC](https://discourse.julialang.org/t/missing-epsilon/39430 "2020-05-13T21:21:51Z")

</div>

Hello, I’m trying to write small epsilon in Julia 1.4.1 (\\ epsilon) but instead epsilon character I see small box (box character or something like that- small, empty rectangle). Anyone had similar problem?

---

## [Hardware hackers domain?](https://discourse.julialang.org/t/hardware-hackers-domain/32839)

<div class="topic-metadata">

**Author:** [@anon92994695](https://discourse.julialang.org/u/anon92994695)\
**Replies:** 45\
**Last updated:** [May 13, 2020, 9:18pm UTC](https://discourse.julialang.org/t/hardware-hackers-domain/32839 "2020-05-13T21:18:07Z")

</div>

Hey, I was wondering if we could get a hardware/hackers/makers domain? Interest in Julia has reached out to microcontrollers, 3-D printers, neural interfaces, IoT, tablets, scientific cameras, yadda yadda. Can us matte…

---

## [Combine more DataFrames with some columns missing](https://discourse.julialang.org/t/combine-more-dataframes-with-some-columns-missing/39415)

<div class="topic-metadata">

**Author:** [@stej](https://discourse.julialang.org/u/stej)\
**Replies:** 4\
**Last updated:** [May 13, 2020, 8:07pm UTC](https://discourse.julialang.org/t/combine-more-dataframes-with-some-columns-missing/39415 "2020-05-13T20:07:09Z")

</div>

Hi all, I deal with API, that returns sometimes incomplete JSON. Some properties are missing. That could be reproduced with this code: using Query using CSV using JSON using DataFrames testjson = """ \[{"A":5, "B":6}, {…

---

## [InteractiveUtils is not aware of CuDevice type](https://discourse.julialang.org/t/interactiveutils-is-not-aware-of-cudevice-type/39358)

<div class="topic-metadata">

**Author:** [@bocc](https://discourse.julialang.org/u/bocc)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 7:11pm UTC](https://discourse.julialang.org/t/interactiveutils-is-not-aware-of-cudevice-type/39358 "2020-05-13T19:11:20Z")

</div>

Hello there, it seems that the info methods provided by InteractiveUtils do not work with the CuDevice type. For example, in the following code using CUDAdrv dev = first(devices()) methodswith(dev) methods(capabilit…

---

## [Package Installation Failing May 2020 - DataFrames ,CSV](https://discourse.julialang.org/t/package-installation-failing-may-2020-dataframes-csv/39352)

<div class="topic-metadata">

**Author:** [@eyedia](https://discourse.julialang.org/u/eyedia)\
**Replies:** 6\
**Last updated:** [May 13, 2020, 6:43pm UTC](https://discourse.julialang.org/t/package-installation-failing-may-2020-dataframes-csv/39352 "2020-05-13T18:43:21Z")

</div>

Today (5/12/2020, 5th May 2020 getting this on Julia TLS (1.0.5) version. It’s our production environment. Help please!! Code: using Pkg Pkg.add(Pkg.PackageSpec(;name=“LearnBase”, version=“0.3”)) specific version was…

---

## [Confusion with arrays and functions](https://discourse.julialang.org/t/confusion-with-arrays-and-functions/39371)

<div class="topic-metadata">

**Author:** [@SambitMishra98](https://discourse.julialang.org/u/SambitMishra98)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 6:13pm UTC](https://discourse.julialang.org/t/confusion-with-arrays-and-functions/39371 "2020-05-13T18:13:12Z")

</div>

I was using a function inside a loop to modify a 2-Dimensional array variable (say DATA) in my code when I realised that the variable changes even when I have not given DATA as an argument or tried to return it to the ma…

---

## [Query @mutate changes other column type](https://discourse.julialang.org/t/query-mutate-changes-other-column-type/39292)

<div class="topic-metadata">

**Author:** [@stej](https://discourse.julialang.org/u/stej)\
**Replies:** 8\
**Last updated:** [May 13, 2020, 5:39pm UTC](https://discourse.julialang.org/t/query-mutate-changes-other-column-type/39292 "2020-05-13T17:39:50Z")

</div>

Hi all, this is my smallest code that I fight with: contents = """ "5674012","aa66aa66" "5674012","9b4e08e5" "5674012","b036aa66,b036aa67,b036aa68" """; batches = CSV.File(IOBuffer(contents); header = \["X1", "Splits"\],…

---

## [Write() done but not writing the content in existing file](https://discourse.julialang.org/t/write-done-but-not-writing-the-content-in-existing-file/39412)

<div class="topic-metadata">

**Author:** [@1634](https://discourse.julialang.org/u/1634)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 5:27pm UTC](https://discourse.julialang.org/t/write-done-but-not-writing-the-content-in-existing-file/39412 "2020-05-13T17:27:06Z")

</div>

Hi, I’d like to write to an existing file. touch cmds #ran in linux to creat an empty file then in Julia I did: cmds=open("cmds", "w") for i in 1:5 cmd= "echo hello echo byebye" println(cmd) #write(cmds,…

---

## [Simple GUI elements on plot](https://discourse.julialang.org/t/simple-gui-elements-on-plot/39284)

<div class="topic-metadata">

**Author:** [@Mikhail\_Kagalenko](https://discourse.julialang.org/u/Mikhail_Kagalenko)\
**Replies:** 8\
**Last updated:** [May 13, 2020, 5:38pm UTC](https://discourse.julialang.org/t/simple-gui-elements-on-plot/39284 "2020-05-13T17:38:10Z")

</div>

Matlab provides tools to build simple GUI applications, i.e., plot with a slider or edit box to change a parameter and observe results. What would be the equivalent package for julia, not requiring installing electron or…

---

## [Benchmarks game](https://discourse.julialang.org/t/benchmarks-game/38544)

<div class="topic-metadata">

**Author:** [@apieum](https://discourse.julialang.org/u/apieum)\
**Replies:** 20\
**Last updated:** [May 13, 2020, 5:20pm UTC](https://discourse.julialang.org/t/benchmarks-game/38544 "2020-05-13T17:20:07Z")

</div>

Hi, this blog post shows bad results for julia in benchmarks game: Which programming language is fastest? In comments the author said “One problem with Julia benchmarks on the Benchmarks Game is that improved Julia prog…

---

## [The Julia Language + Google Season of Docs 2020](https://discourse.julialang.org/t/the-julia-language-google-season-of-docs-2020/39279)

<div class="topic-metadata">

**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 0\
**Last updated:** [May 11, 2020, 12:36pm UTC](https://discourse.julialang.org/t/the-julia-language-google-season-of-docs-2020/39279 "2020-05-11T12:36:45Z")

</div>

Hey all! We are excited to announce that the Julia Language has been selected to participate in Google Season of Docs. We have a number of awesome projects setup for GSoD that you can find on the JuliaLang website. If y…

---

## [BoundError in Flux.train! with DiffEqFlux](https://discourse.julialang.org/t/bounderror-in-flux-train-with-diffeqflux/39413)

<div class="topic-metadata">

**Author:** [@Geoffrey](https://discourse.julialang.org/u/Geoffrey)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 4:43pm UTC](https://discourse.julialang.org/t/bounderror-in-flux-train-with-diffeqflux/39413 "2020-05-13T16:43:16Z")

</div>

Hi, I’m trying to use DiffEqFlux to solve a scalar ode which looks like : du(t) = f(X(t)) - a \* u, where X(t) is a set of functions of time. I modeled f with a neural network and i’m trying to optimize the parameter of …

---

## [Weird interplay between scale and lightposition in Makie](https://discourse.julialang.org/t/weird-interplay-between-scale-and-lightposition-in-makie/39363)

<div class="topic-metadata">

**Author:** [@photor](https://discourse.julialang.org/u/photor)\
**Replies:** 1\
**Last updated:** [May 13, 2020, 4:33pm UTC](https://discourse.julialang.org/t/weird-interplay-between-scale-and-lightposition-in-makie/39363 "2020-05-13T16:33:12Z")

</div>

I was drawing a surface plot of some configuration of a quantum system, using the following code: using Makie l = w = 30.0 p = m = 120 x=l\*\[(i-0.5)/p-0.5 for i = 1:p\] #x ranges in (-15,15) y=w\*\[(i-0.5)/m-0.5 for i …

---

## [Objective function "limit reached" status in JuMP](https://discourse.julialang.org/t/objective-function-limit-reached-status-in-jump/39349)

<div class="topic-metadata">

**Author:** [@ivborissov](https://discourse.julialang.org/u/ivborissov)\
**Replies:** 5\
**Last updated:** [May 13, 2020, 2:46pm UTC](https://discourse.julialang.org/t/objective-function-limit-reached-status-in-jump/39349 "2020-05-13T14:46:43Z")

</div>

Hi, Can JuMP report that an objective function has reached some predefined limit? My problem looks the following. I am looking for a Min or Max value of a variable x\[1\] within the bounds (lets say \[1e-9,1e9\]) w.r.t som…

---

## [Heatmap Plots.jl](https://discourse.julialang.org/t/heatmap-plots-jl/39406)

<div class="topic-metadata">

**Author:** [@Kruxigt](https://discourse.julialang.org/u/Kruxigt)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 2:31pm UTC](https://discourse.julialang.org/t/heatmap-plots-jl/39406 "2020-05-13T14:31:49Z")

</div>

Good afternoon! I can not get the heatmap plot in the Plots.jl package to do what I would like. If I do: using Plots backend(:plotly) p = heatmap(\[1,2,3,1,2,3,1,2,3\],\[1,1,1,2,2,2,3,3,3\],\[1,1,1,1,1,1,1,1,1\]) gui(p) I …

---

## [What's the correct way to including functions that only got introduce from a certain version of Julia?](https://discourse.julialang.org/t/whats-the-correct-way-to-including-functions-that-only-got-introduce-from-a-certain-version-of-julia/39379)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 3\
**Last updated:** [May 13, 2020, 2:14pm UTC](https://discourse.julialang.org/t/whats-the-correct-way-to-including-functions-that-only-got-introduce-from-a-certain-version-of-julia/39379 "2020-05-13T14:14:01Z")

</div>

I want to support all LTS Julia versions which is currently 1.0.5. However, some functions like nonmissingtype is only introduced in 1.3 What’s the correct way to support these type of functions? Should I just check for…

---

## [Julia raspbian packaging query](https://discourse.julialang.org/t/julia-raspbian-packaging-query/38445)

<div class="topic-metadata">

**Author:** [@plugwash](https://discourse.julialang.org/u/plugwash)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 2:13pm UTC](https://discourse.julialang.org/t/julia-raspbian-packaging-query/38445 "2020-05-13T14:13:15Z")

</div>

(apologies if this is the wrong forum, there didn’t seem to be a specific one for distro packaging queries) I maintain raspbian, an armv6 rebuild of Debian. I have been looking to update the julia package in raspbian bu…

---

## [Function like numpy.stack](https://discourse.julialang.org/t/function-like-numpy-stack/39394)

<div class="topic-metadata">

**Author:** [@ponez](https://discourse.julialang.org/u/ponez)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 1:40pm UTC](https://discourse.julialang.org/t/function-like-numpy-stack/39394 "2020-05-13T13:40:06Z")

</div>

Is there any function like numpy.stack(arrays, axis=)，I’ve tried repeat(a, inner=()), but this method can’t specify axis, and reshape after repeat doesn’t work. julia\> a 2-element Array{Int64,1}: 2 1 julia\> c = repeat…

---

## [Function not faster than global scope](https://discourse.julialang.org/t/function-not-faster-than-global-scope/39389)

<div class="topic-metadata">

**Author:** [@JasonHall](https://discourse.julialang.org/u/JasonHall)\
**Replies:** 7\
**Last updated:** [May 13, 2020, 12:39pm UTC](https://discourse.julialang.org/t/function-not-faster-than-global-scope/39389 "2020-05-13T12:39:34Z")

</div>

I am following along in Adrian Salceanu’s book “Julia Programming Projects”. He is on Julia 1.0 and I am using 1.4. He says that running in the global scope is slower than wrapping in a function because the function is…

---

## [Juliabox.com launch disable?](https://discourse.julialang.org/t/juliabox-com-launch-disable/38716)

<div class="topic-metadata">

**Author:** [@fdq09eca](https://discourse.julialang.org/u/fdq09eca)\
**Replies:** 3\
**Last updated:** [May 13, 2020, 12:38pm UTC](https://discourse.julialang.org/t/juliabox-com-launch-disable/38716 "2020-05-13T12:38:47Z")

</div>

I am extreme new for Julia and would like to learn this language from juliabox.com but I after I login with GitHub OAuth, there is no button is available for me. how am I suppose to use this website? am I missing sth…

---

## [Some variable not defined, even though it is](https://discourse.julialang.org/t/some-variable-not-defined-even-though-it-is/39386)

<div class="topic-metadata">

**Author:** [@HoldenCaulfield](https://discourse.julialang.org/u/HoldenCaulfield)\
**Replies:** 7\
**Last updated:** [May 13, 2020, 11:35am UTC](https://discourse.julialang.org/t/some-variable-not-defined-even-though-it-is/39386 "2020-05-13T11:35:44Z")

</div>

Hi, I have two similar functions, for training a Boltzmann machine. Here’s the first: function train(ptrns, n\_h, ϵ, n\_G\_s, steps) w = rand(Normal(0,0.01),size(ptrns,2)+1, n\_h+1) h = hcat(zeros(1,n\_h),1); hi…

---

## [Converting a matrix into an array of arrays](https://discourse.julialang.org/t/converting-a-matrix-into-an-array-of-arrays/17038)

<div class="topic-metadata">

**Author:** [@braamvandyk](https://discourse.julialang.org/u/braamvandyk)\
**Replies:** 7\
**Last updated:** [May 13, 2020, 11:11am UTC](https://discourse.julialang.org/t/converting-a-matrix-into-an-array-of-arrays/17038 "2020-05-13T11:11:18Z")

</div>

Hi all I have seen many examples of converting an array of arrays into a matrix, but I would like to go the other way. What I have cobbled together works, but may not be the most elegant or fast solution. I would apprec…

---

## [Run() returns not recognized as an internal or external command](https://discourse.julialang.org/t/run-returns-not-recognized-as-an-internal-or-external-command/39343)

<div class="topic-metadata">

**Author:** [@1634](https://discourse.julialang.org/u/1634)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 10:54am UTC](https://discourse.julialang.org/t/run-returns-not-recognized-as-an-internal-or-external-command/39343 "2020-05-13T10:54:10Z")

</div>

Hi community, I tried to run linux commands in Julia through run(pipeline(\`cmd /c Rscript x.R\`, \`cmd /c gzip\`, \`cmd /c julia xx.jl\`) |\> file) but then I get ‘Rscript’ is not recognized as an internal or external c…

---

## [Iterating over the columns of a matrix](https://discourse.julialang.org/t/iterating-over-the-columns-of-a-matrix/39385)

<div class="topic-metadata">

**Author:** [@BMO](https://discourse.julialang.org/u/BMO)\
**Replies:** 3\
**Last updated:** [May 13, 2020, 10:49am UTC](https://discourse.julialang.org/t/iterating-over-the-columns-of-a-matrix/39385 "2020-05-13T10:49:12Z")

</div>

I want to iterate a function whose argument is a vector. The vectors to iterate on are the columns of a matrix. I was “slicing” the matrix into columns following Converting a matrix into an array of arrays and then itera…

---

## [Loading image and convert it to AFArray. (Arrayfire and image processing)](https://discourse.julialang.org/t/loading-image-and-convert-it-to-afarray-arrayfire-and-image-processing/27872)

<div class="topic-metadata">

**Author:** [@fergaletto](https://discourse.julialang.org/u/fergaletto)\
**Replies:** 2\
**Last updated:** [May 13, 2020, 9:43am UTC](https://discourse.julialang.org/t/loading-image-and-convert-it-to-afarray-arrayfire-and-image-processing/27872 "2020-05-13T09:43:11Z")

</div>

Hi There, I want to perform image processing with julia using ArrayFire, basically i want to load an image and perform a couple of operations such as applying a bilateral filter and white balance using my GPU. I instal…

---

## [Makie recipe specialisation for specific types?](https://discourse.julialang.org/t/makie-recipe-specialisation-for-specific-types/39157)

<div class="topic-metadata">

**Author:** [@Ward9250](https://discourse.julialang.org/u/Ward9250)\
**Replies:** 5\
**Last updated:** [May 13, 2020, 4:05am UTC](https://discourse.julialang.org/t/makie-recipe-specialisation-for-specific-types/39157 "2020-05-13T04:05:28Z")

</div>

Hiya, so this is a bit of a weird thing to own up to, but this is the first time I’ve ever seriously sat down and thought - right this BioJulia package needs to plotting functionality! (I know right, normally I’m obsesse…

---

## [How to create tree from struct](https://discourse.julialang.org/t/how-to-create-tree-from-struct/39372)

<div class="topic-metadata">

**Author:** [@wiktorkujawa](https://discourse.julialang.org/u/wiktorkujawa)\
**Replies:** 4\
**Last updated:** [May 13, 2020, 9:08am UTC](https://discourse.julialang.org/t/how-to-create-tree-from-struct/39372 "2020-05-13T09:08:46Z")

</div>

I want to create tree with struct. Here’s my approach: mutable struct node{T} data::T left::node right::node node(T)= (data=T; left= Nothing; right= Nothing) end root=node(1) root.left=node(2) root.right=node(3…

[Previous page](https://discourse.julialang.org/latest.md?page=1746)

[Next page](https://discourse.julialang.org/latest.md?page=1748)