# Latest

**URL:** https://discourse.julialang.org/latest.md?page=995

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

**Page:** 996

---

## [Symbolic Arrays have issues with Complex Numbers](https://discourse.julialang.org/t/symbolic-arrays-have-issues-with-complex-numbers/83538)

<div class="topic-metadata">

**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 1\
**Last updated:** [June 30, 2022, 9:35am UTC](https://discourse.julialang.org/t/symbolic-arrays-have-issues-with-complex-numbers/83538 "2022-06-30T09:35:11Z")

</div>

I can’t work with complex numbers multiplying Symbolic Arrays. Here an example: using Symbolics, SpecialFunctions N = 3 @variables r\[1:N, 1:N\], ϕ\[1:N, 1:N\] H = hankelh1.(0, r) P = cos.(ϕ) Q = im.\*cos.(ϕ)# also does n…

---

## [Loading a precompiled module does not respect the module import order](https://discourse.julialang.org/t/loading-a-precompiled-module-does-not-respect-the-module-import-order/83560)

<div class="topic-metadata">

**Author:** [@thautwarm](https://discourse.julialang.org/u/thautwarm)\
**Replies:** 0\
**Last updated:** [June 30, 2022, 9:34am UTC](https://discourse.julialang.org/t/loading-a-precompiled-module-does-not-respect-the-module-import-order/83560 "2022-06-30T09:34:52Z")

</div>

I’ve just made a package JuliaPythonAdaptor.jl that helps automatically setting up environment variables required by PythonCall.jl. Things works pretty fine if I use these two packages in REPL: # 'JuliaPythonAdaptor.\_\_…

---

## [DifferentialEquations.jl How to speed up the solver](https://discourse.julialang.org/t/differentialequations-jl-how-to-speed-up-the-solver/83549)

<div class="topic-metadata">

**Author:** [@Nalaka](https://discourse.julialang.org/u/Nalaka)\
**Replies:** 3\
**Last updated:** [June 30, 2022, 9:32am UTC](https://discourse.julialang.org/t/differentialequations-jl-how-to-speed-up-the-solver/83549 "2022-06-30T09:32:26Z")

</div>

I am using Julia to solve set of differential equations of a omni-wheeled mobile robot. It took 1264.41 sec (21.07 min) to solve the system (But in mathematica, it took less than 4s). In the time, it showed 99% time is f…

---

## [Efficient Evaluation of a Matrix of Function Products](https://discourse.julialang.org/t/efficient-evaluation-of-a-matrix-of-function-products/83466)

<div class="topic-metadata">

**Author:** [@martintb](https://discourse.julialang.org/u/martintb)\
**Replies:** 8\
**Last updated:** [June 30, 2022, 7:30am UTC](https://discourse.julialang.org/t/efficient-evaluation-of-a-matrix-of-function-products/83466 "2022-06-30T07:30:08Z")

</div>

Hi all, I’m trying to compute every product of two functions of a set of different functions fv (e.g., a set of wavefunctions) at different x to obtain a matrix y for each x of shape NxN where N is the number of functio…

---

## [How to use GLMakie in jupyter notebook?](https://discourse.julialang.org/t/how-to-use-glmakie-in-jupyter-notebook/83552)

<div class="topic-metadata">

**Author:** [@ZiyiLiu](https://discourse.julialang.org/u/ZiyiLiu)\
**Replies:** 5\
**Last updated:** [June 30, 2022, 7:11am UTC](https://discourse.julialang.org/t/how-to-use-glmakie-in-jupyter-notebook/83552 "2022-06-30T07:11:10Z")

</div>

Hi, I am studying julia from yesterday, and I met a question when using GLMakie and python together in jupyter notebook. Then problem is that I can’t use ‘using Makie’ in my code. The error is in the picture below. Als…

---

## [Makie in Jupyter?](https://discourse.julialang.org/t/makie-in-jupyter/44525)

<div class="topic-metadata">

**Author:** [@bobmccrory](https://discourse.julialang.org/u/bobmccrory)\
**Replies:** 4\
**Last updated:** [June 30, 2022, 5:51am UTC](https://discourse.julialang.org/t/makie-in-jupyter/44525 "2022-06-30T05:51:08Z")

</div>

I’m trying to install and use Makie in a Jupyter notebook: No luck. Tried the installation of WGLMakie: No luck. Does anyone have this working on a Windows10 machine? If it helps, the code below worked - once - and then…

---

## [Slicing and boolean indexing in multidimensional arrays](https://discourse.julialang.org/t/slicing-and-boolean-indexing-in-multidimensional-arrays/83522)

<div class="topic-metadata">

**Author:** [@bryce](https://discourse.julialang.org/u/bryce)\
**Replies:** 5\
**Last updated:** [June 30, 2022, 5:21am UTC](https://discourse.julialang.org/t/slicing-and-boolean-indexing-in-multidimensional-arrays/83522 "2022-06-30T05:21:20Z")

</div>

I’m curious why the following 3D array slicing works for the i index but not for the j index: T = Array(reshape(1:2\*3\*4, 2,3,4)) i = zeros(Bool, 2,3) i\[1,2:3\] .= 1 display(T\[i,:\]) j = zeros(Bool, 3,4) j\[1,2:3\] .= 1 disp…

---

## [JuMP.write\_to\_file small change to model](https://discourse.julialang.org/t/jump-write-to-file-small-change-to-model/83543)

<div class="topic-metadata">

**Author:** [@Stuart\_Rogers](https://discourse.julialang.org/u/Stuart_Rogers)\
**Replies:** 2\
**Last updated:** [June 30, 2022, 2:34am UTC](https://discourse.julialang.org/t/jump-write-to-file-small-change-to-model/83543 "2022-06-30T02:34:26Z")

</div>

I have created a large LP in a JuMP model. I want to write a small variation, e.g. fixing a variable or changing the RHS of a scalar constraint, of the LP to a MPS file using JuMP. write\_to\_file. Once the original LP has…

---

## [Iterators.product OutOfMemoryError()](https://discourse.julialang.org/t/iterators-product-outofmemoryerror/83542)

<div class="topic-metadata">

**Author:** [@Yuri\_Mizusawa](https://discourse.julialang.org/u/Yuri_Mizusawa)\
**Replies:** 2\
**Last updated:** [June 30, 2022, 2:29am UTC](https://discourse.julialang.org/t/iterators-product-outofmemoryerror/83542 "2022-06-30T02:29:48Z")

</div>

Hi, I have the following code: ary\_comb\_n=collect(Iterators.product(n\_max\_O...)) Where n\_max\_O is an array with vectors like this \[ \[0,1,2,3,4\] ,\[0,1,2\] \]. Iterators.product gives me the combinatory of all the vec…

---

## [Arrays with periodic boundaries](https://discourse.julialang.org/t/arrays-with-periodic-boundaries/4015)

<div class="topic-metadata">

**Author:** [@stefanocampanella](https://discourse.julialang.org/u/stefanocampanella)\
**Replies:** 5\
**Last updated:** [June 30, 2022, 2:07am UTC](https://discourse.julialang.org/t/arrays-with-periodic-boundaries/4015 "2022-06-30T02:07:45Z")

</div>

Hi! I am a student in the STEM field. I’m not totally new to Julia, but I really have little experience as a programmer. A problem which I encounter very often is dealing with arrays with periodic/cyclic boundaries (es.…

---

## [Banyan Julia - large-scale Julia data frames, images, arrays, ML models, and more](https://discourse.julialang.org/t/banyan-julia-large-scale-julia-data-frames-images-arrays-ml-models-and-more/83540)

<div class="topic-metadata">

**Author:** [@calebwin](https://discourse.julialang.org/u/calebwin)\
**Replies:** 0\
**Last updated:** [June 30, 2022, 12:40am UTC](https://discourse.julialang.org/t/banyan-julia-large-scale-julia-data-frames-images-arrays-ml-models-and-more/83540 "2022-06-30T00:40:58Z")

</div>

I’m excited to make our first public announcement about Banyan Julia - a suite of packages that let you use popular Julia APIs to process massive datasets on and off the cloud (via sampling): BanyanDataFrames.jl for D…

---

## [If then statement vs Grid](https://discourse.julialang.org/t/if-then-statement-vs-grid/83537)

<div class="topic-metadata">

**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 3\
**Last updated:** [June 30, 2022, 12:01am UTC](https://discourse.julialang.org/t/if-then-statement-vs-grid/83537 "2022-06-30T00:01:52Z")

</div>

My goal is to create a piecewise function in Julia parsimoniously. u(x,y) = y if x = 0 u(x,y) = y -1 if x \\neq 0 I get the following: julia\> FC(x) = (x==0):(0):(1) FC (generic function with 1 method) julia\> u(x,y) …

---

## [Poster session—can I give a link to reveal.js slides instead of uploading?](https://discourse.julialang.org/t/poster-session-can-i-give-a-link-to-reveal-js-slides-instead-of-uploading/83383)

<div class="topic-metadata">

**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 1\
**Last updated:** [June 29, 2022, 11:01pm UTC](https://discourse.julialang.org/t/poster-session-can-i-give-a-link-to-reveal-js-slides-instead-of-uploading/83383 "2022-06-29T23:01:42Z")

</div>

I recently got the email request to upload my poster session materials to juliacon.org. There it says, For posters, please upload the 3 minute video and the actual poster file in two seperate uploads with different fil…

---

## [How to write a simple macro](https://discourse.julialang.org/t/how-to-write-a-simple-macro/83420)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 19\
**Last updated:** [June 29, 2022, 10:31pm UTC](https://discourse.julialang.org/t/how-to-write-a-simple-macro/83420 "2022-06-29T22:31:21Z")

</div>

I have lines similar to this a lot in my code: if chi\_factor \> 0.85 chi\_factor = 0.85 end I would like to write it like this: @limit chi\_factor 0.85 I cannot use a function for this because a function cannot chan…

---

## [Looping Over Two Variables (indexes) in a DataFrame](https://discourse.julialang.org/t/looping-over-two-variables-indexes-in-a-dataframe/83531)

<div class="topic-metadata">

**Author:** [@tgalois](https://discourse.julialang.org/u/tgalois)\
**Replies:** 1\
**Last updated:** [June 29, 2022, 8:59pm UTC](https://discourse.julialang.org/t/looping-over-two-variables-indexes-in-a-dataframe/83531 "2022-06-29T20:59:53Z")

</div>

Hello Everyone, I am running a simulation study looping (for loop) over two indexes. In R we can do this:: for i in 1:100{ for j in c(15, 30, 50, 400){ df1$result\[df1$snum==i & df1$szise==j\]\<-dosomething\[df2$snum=i & …

---

## [Looking for collaborators - implementing SLIDE in julia](https://discourse.julialang.org/t/looking-for-collaborators-implementing-slide-in-julia/83482)

<div class="topic-metadata">

**Author:** [@RickDW](https://discourse.julialang.org/u/RickDW)\
**Replies:** 12\
**Last updated:** [June 29, 2022, 8:39pm UTC](https://discourse.julialang.org/t/looking-for-collaborators-implementing-slide-in-julia/83482 "2022-06-29T20:39:35Z")

</div>

Hi everyone, a while back I had a quick discussion with @outlace (over here) about implementing SLIDE. The basic idea is that you don’t need expensive GPUs or other hardware accelerators to train neural nets. All you nee…

---

## [Formatting the x-axis with hex values](https://discourse.julialang.org/t/formatting-the-x-axis-with-hex-values/83528)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 12\
**Last updated:** [June 29, 2022, 8:24pm UTC](https://discourse.julialang.org/t/formatting-the-x-axis-with-hex-values/83528 "2022-06-29T20:24:13Z")

</div>

I have the following code: using Plots p = histogram(randn(1000)\*10, bins=:scott, weights=repeat(1:5, outer=200)) p How can I achieve that the x axis shows hex values instead of decimal values?

---

## [Small-multiples plots in Plots.jl](https://discourse.julialang.org/t/small-multiples-plots-in-plots-jl/83529)

<div class="topic-metadata">

**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 2\
**Last updated:** [June 29, 2022, 8:21pm UTC](https://discourse.julialang.org/t/small-multiples-plots-in-plots-jl/83529 "2022-06-29T20:21:13Z")

</div>

I have time series for each state in the US. I have grouped the states by a geographic grouping factor. There are 8 state groups. I’d like to make 8 panels, one for each state group, within the panel I want each state t…

---

## [Dataframe Joins in a loop](https://discourse.julialang.org/t/dataframe-joins-in-a-loop/83476)

<div class="topic-metadata">

**Author:** [@Guido](https://discourse.julialang.org/u/Guido)\
**Replies:** 4\
**Last updated:** [June 29, 2022, 7:40pm UTC](https://discourse.julialang.org/t/dataframe-joins-in-a-loop/83476 "2022-06-29T19:40:49Z")

</div>

Hi all, I’m learning Julia and I’m stuck trying to merge several dataframes into only one using a loop. For instances, suppose that I have 4 dataframes called A, B, C and D. They have the same column names except for th…

---

## [CUDA.jl - Better GPU but Worse Performance](https://discourse.julialang.org/t/cuda-jl-better-gpu-but-worse-performance/83337)

<div class="topic-metadata">

**Author:** [@moukann](https://discourse.julialang.org/u/moukann)\
**Replies:** 10\
**Last updated:** [June 29, 2022, 6:45pm UTC](https://discourse.julialang.org/t/cuda-jl-better-gpu-but-worse-performance/83337 "2022-06-29T18:45:19Z")

</div>

Hello all, I have a question regarding to general usage of CUDA.jl, not a code problem. So we have 2 different computers, both is running on Ubuntu. One of them has Nvidia Quadro P2000 5GB DDR5 160Bit graphics card and…

---

## [AMD GPU and CPU top 1 supercomputer, 1.1 exaflops (and other 10+ "AI exaflops")](https://discourse.julialang.org/t/amd-gpu-and-cpu-top-1-supercomputer-1-1-exaflops-and-other-10-ai-exaflops/83527)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [June 29, 2022, 4:54pm UTC](https://discourse.julialang.org/t/amd-gpu-and-cpu-top-1-supercomputer-1-1-exaflops-and-other-10-ai-exaflops/83527 "2022-06-29T16:54:45Z")

</div>

In case people missed it, there’s a new top 1, exascale, supercomputer out, Frontier. A. And it’s 50% more power-efficient than anything out there. Intel and Nvidia are almost gone from the top 10 list of top500 and gr…

---

## [Removing singularities from callable functions built from symbolic expressions](https://discourse.julialang.org/t/removing-singularities-from-callable-functions-built-from-symbolic-expressions/83505)

<div class="topic-metadata">

**Author:** [@mrhardman](https://discourse.julialang.org/u/mrhardman)\
**Replies:** 2\
**Last updated:** [June 29, 2022, 5:11pm UTC](https://discourse.julialang.org/t/removing-singularities-from-callable-functions-built-from-symbolic-expressions/83505 "2022-06-29T17:11:09Z")

</div>

I have a basic question regarding building functions from symbolic expressions for which I cannot find the answer on the documentation (Symbolic Calculations and Building Callable Functions · Symbolics.jl) Suppose that …

---

## [Generalized affects in MTK - what's a good interface?](https://discourse.julialang.org/t/generalized-affects-in-mtk-whats-a-good-interface/83390)

<div class="topic-metadata">

**Author:** [@dodoplus](https://discourse.julialang.org/u/dodoplus)\
**Replies:** 4\
**Last updated:** [June 29, 2022, 4:57pm UTC](https://discourse.julialang.org/t/generalized-affects-in-mtk-whats-a-good-interface/83390 "2022-06-29T16:57:08Z")

</div>

Hi, I’ve recently started a pull request in an attempt to add more generalized affect! support to MTK (and also to support discrete\_events, which is taken on by others) The reason I think this is needed is that in some…

---

## [Build simple GUIs with MiniFB](https://discourse.julialang.org/t/build-simple-guis-with-minifb/46195)

<div class="topic-metadata">

**Author:** [@avik](https://discourse.julialang.org/u/avik)\
**Replies:** 40\
**Last updated:** [June 29, 2022, 4:37pm UTC](https://discourse.julialang.org/t/build-simple-guis-with-minifb/46195 "2022-06-29T16:37:58Z")

</div>

I’d like to announce a little vacation project of mine. I’ve just released the first version of MiniFB.jl, a Julia wrapper around a small C library called MiniFB. MiniFB is possibly the simplest way to get a graphical w…

---

## [Base.methods matches subtypes and supertypes](https://discourse.julialang.org/t/base-methods-matches-subtypes-and-supertypes/83525)

<div class="topic-metadata">

**Author:** [@tictaccat](https://discourse.julialang.org/u/tictaccat)\
**Replies:** 0\
**Last updated:** [June 29, 2022, 4:21pm UTC](https://discourse.julialang.org/t/base-methods-matches-subtypes-and-supertypes/83525 "2022-06-29T16:21:05Z")

</div>

Base.methods seems to return both subtypes and supertypes: julia\> f(x::Integer) = 3 f (generic function with 1 method) julia\> methods(f, (Number,)) # 1 method for generic function "f": \[1\] f(x::Integer) in Main at REPL…

---

## [Store DataFrame or filepath for CSV.read?](https://discourse.julialang.org/t/store-dataframe-or-filepath-for-csv-read/83489)

<div class="topic-metadata">

**Author:** [@RicardoFR](https://discourse.julialang.org/u/RicardoFR)\
**Replies:** 2\
**Last updated:** [June 29, 2022, 4:19pm UTC](https://discourse.julialang.org/t/store-dataframe-or-filepath-for-csv-read/83489 "2022-06-29T16:19:35Z")

</div>

Hello all! I’m working with some data using CSV.read and the DataFrame type. The data in its raw form is seldom needed in my code, which got me thinking if I indeed need to store it in my mutable struct in the first pla…

---

## [Dictionary construction is quite slow?](https://discourse.julialang.org/t/dictionary-construction-is-quite-slow/83485)

<div class="topic-metadata">

**Author:** [@christmas\_jones](https://discourse.julialang.org/u/christmas_jones)\
**Replies:** 15\
**Last updated:** [June 29, 2022, 4:16pm UTC](https://discourse.julialang.org/t/dictionary-construction-is-quite-slow/83485 "2022-06-29T16:16:24Z")

</div>

Just comparing python to julia for dictionary construction, and it seems very slow. In my particular use case it is much worse even than the MWE below (where my keys are more complicated). So my question is, what is the…

---

## [We need more helpful error messages in ModelingToolkit](https://discourse.julialang.org/t/we-need-more-helpful-error-messages-in-modelingtoolkit/82917)

<div class="topic-metadata">

**Author:** [@dodoplus](https://discourse.julialang.org/u/dodoplus)\
**Replies:** 11\
**Last updated:** [June 29, 2022, 4:13pm UTC](https://discourse.julialang.org/t/we-need-more-helpful-error-messages-in-modelingtoolkit/82917 "2022-06-29T16:13:58Z")

</div>

Hi, Trying to solve a model, I’m getting a really unhelpful message: @named x = MixingVolume() sys = structural\_simplify(x) prob = ODAEProblem(sys, \[\], (0, 10.0)) sol = solve(prob, Tsit5()) MethodError: no method …

---

## [How to create all possible k-mers with a set of alphabets?](https://discourse.julialang.org/t/how-to-create-all-possible-k-mers-with-a-set-of-alphabets/83186)

<div class="topic-metadata">

**Author:** [@Bharat\_Ravi](https://discourse.julialang.org/u/Bharat_Ravi)\
**Replies:** 12\
**Last updated:** [June 29, 2022, 4:07pm UTC](https://discourse.julialang.org/t/how-to-create-all-possible-k-mers-with-a-set-of-alphabets/83186 "2022-06-29T16:07:03Z")

</div>

I am trying to use Iterators.product to generate a list of all possible k-mers with a set of alphabets. Since I am a biologist, these letters happen to be the bases of DNA :smiley: : “ATGC” If I want to generate 3-me…

---

## [Favorite lectures on the Finite Element Method?](https://discourse.julialang.org/t/favorite-lectures-on-the-finite-element-method/83211)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [June 29, 2022, 3:22pm UTC](https://discourse.julialang.org/t/favorite-lectures-on-the-finite-element-method/83211 "2022-06-29T15:22:12Z")

</div>

Do you have a favorite set of lectures on the Finite Element Method? Possibly a set of lectures with a heavy list of programming exercises that encourages students to build all the building blocks of a modern software li…

[Previous page](https://discourse.julialang.org/latest.md?page=994)

[Next page](https://discourse.julialang.org/latest.md?page=996)