# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1642

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

**Page:** 1643

---

## [SymPy vs Sympy.jl and/or symengine.jl](https://discourse.julialang.org/t/sympy-vs-sympy-jl-and-or-symengine-jl/39464)

<div class="topic-metadata">

**Author:** [@SanAlphaTau](https://discourse.julialang.org/u/SanAlphaTau)\
**Replies:** 14\
**Last updated:** [September 2, 2020, 12:13pm UTC](https://discourse.julialang.org/t/sympy-vs-sympy-jl-and-or-symengine-jl/39464 "2020-09-02T12:13:15Z")

</div>

Hello, I’ve been using python and sympy to build up a series of quite large symbolic equations. I then use python to evaluate them numerically and solve for minima (using a combination of lambdify and scipy optimize). T…

---

## [Parallelism? Async != Parallel?](https://discourse.julialang.org/t/parallelism-async-parallel/45941)

<div class="topic-metadata">

**Author:** [@ok\_ok](https://discourse.julialang.org/u/ok_ok)\
**Replies:** 11\
**Last updated:** [September 2, 2020, 12:00pm UTC](https://discourse.julialang.org/t/parallelism-async-parallel/45941 "2020-09-02T12:00:41Z")

</div>

Hi Guys, for me the Documentation about Parallel Programming is kinda Confusing in Julia. For me its hard to distinguish the first two Groups of Parallel Programming. https://docs.julialang.org/en/v1/manual/parallel-co…

---

## [How to make a Custom Layer work on GPU?](https://discourse.julialang.org/t/how-to-make-a-custom-layer-work-on-gpu/45836)

<div class="topic-metadata">

**Author:** [@pineapplehunter](https://discourse.julialang.org/u/pineapplehunter)\
**Replies:** 3\
**Last updated:** [September 2, 2020, 11:57am UTC](https://discourse.julialang.org/t/how-to-make-a-custom-layer-work-on-gpu/45836 "2020-09-02T11:57:02Z")

</div>

Hi. I’m trying to implement a funnel activation(FReLU) like this github for fun. https://github.com/megvii-model/FunnelAct An Pytorch implementation looks like this. import torch import torch.nn as nn class FReLU(nn.M…

---

## [Understanding LightGraph's depth-first search](https://discourse.julialang.org/t/understanding-lightgraphs-depth-first-search/45785)

<div class="topic-metadata">

**Author:** [@mroavi](https://discourse.julialang.org/u/mroavi)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 11:39am UTC](https://discourse.julialang.org/t/understanding-lightgraphs-depth-first-search/45785 "2020-09-02T11:39:33Z")

</div>

Hello everyone, I want to use the depth-first search functionality offered by LightGraphs.jl. However, I don’t seem to understand the results given by the dfs\_parents function. I wrote a simple example using LightGrap…

---

## [Julia 1.5.1 slows down when running multiple instances in parallel](https://discourse.julialang.org/t/julia-1-5-1-slows-down-when-running-multiple-instances-in-parallel/45934)

<div class="topic-metadata">

**Author:** [@stakaz](https://discourse.julialang.org/u/stakaz)\
**Replies:** 7\
**Last updated:** [September 2, 2020, 11:27am UTC](https://discourse.julialang.org/t/julia-1-5-1-slows-down-when-running-multiple-instances-in-parallel/45934 "2020-09-02T11:27:57Z")

</div>

Hello, I noticed a weird behavior in julia 1.5.1 performance (e. g. loading packages) compared to julia 1.1.0. I have a batch script which starts various julia scripts simultaneously on a cluster. In a simplified versi…

---

## [Makie: animation becomes slow after redrawing surface about 25 times](https://discourse.julialang.org/t/makie-animation-becomes-slow-after-redrawing-surface-about-25-times/45582)

<div class="topic-metadata">

**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 8\
**Last updated:** [September 2, 2020, 10:16am UTC](https://discourse.julialang.org/t/makie-animation-becomes-slow-after-redrawing-surface-about-25-times/45582 "2020-09-02T10:16:27Z")

</div>

Context I am working on an example of a 3-D visualization of a 2-D glacier flow. Until now the visualization is done for a very small problem (256x256 grid points). Later it should also work for much larger problems. Pr…

---

## [A package for Inter-rater Reliability measures](https://discourse.julialang.org/t/a-package-for-inter-rater-reliability-measures/45938)

<div class="topic-metadata">

**Author:** [@FPGro](https://discourse.julialang.org/u/FPGro)\
**Replies:** 0\
**Last updated:** [September 2, 2020, 9:30am UTC](https://discourse.julialang.org/t/a-package-for-inter-rater-reliability-measures/45938 "2020-09-02T09:30:29Z")

</div>

Hello folks, Remotely related to something I work on, I stumbled about inter-rater relibility measures (see Wikipedia for example) and since I couldn’t find any existing implementations I decided to try implementing one…

---

## [Fastest way to create new column in DataFrames.jl](https://discourse.julialang.org/t/fastest-way-to-create-new-column-in-dataframes-jl/45933)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 0\
**Last updated:** [September 2, 2020, 6:21am UTC](https://discourse.julialang.org/t/fastest-way-to-create-new-column-in-dataframes-jl/45933 "2020-09-02T06:21:48Z")

</div>

I found 3 ways to create new columns in DataFrames.jl (two of which are equivalent) df = DataFrame(a = rand(1\_000\_000), b= rand(1\_000\_000)) @time transform!(df, \[:a, :b\] =\> (a,b)-\>a + b) @time transform!(df, \[:a, :b\] =\>…

---

## [Stack overflow when reshaping image array](https://discourse.julialang.org/t/stack-overflow-when-reshaping-image-array/45927)

<div class="topic-metadata">

**Author:** [@timmor](https://discourse.julialang.org/u/timmor)\
**Replies:** 2\
**Last updated:** [September 2, 2020, 5:33am UTC](https://discourse.julialang.org/t/stack-overflow-when-reshaping-image-array/45927 "2020-09-02T05:33:05Z")

</div>

I’m trying to read a few frames of video from a file and reshape the data into a three-dimensional array. I’m getting an infinite recursion when reshaping the array. using VideoIO io = VideoIO.testvideo("ladybird") f =…

---

## [Where is \`===\` actually defined?](https://discourse.julialang.org/t/where-is-actually-defined/45926)

<div class="topic-metadata">

**Author:** [@cnaak](https://discourse.julialang.org/u/cnaak)\
**Replies:** 5\
**Last updated:** [September 2, 2020, 3:03am UTC](https://discourse.julialang.org/t/where-is-actually-defined/45926 "2020-09-02T03:03:51Z")

</div>

In operators.jl one sees that ==(x, y) falls back to ===(x, y), but interestingly, ==='s definition in operators.jl is just… === I’ve never seen Julia syntax like it! :thinking: On the repl, one gets: julia\> methods(…

---

## [Switched from Python to Julia for speed, but it's not faster...?](https://discourse.julialang.org/t/switched-from-python-to-julia-for-speed-but-its-not-faster/45904)

<div class="topic-metadata">

**Author:** [@PaulScotti](https://discourse.julialang.org/u/PaulScotti)\
**Replies:** 12\
**Last updated:** [September 2, 2020, 2:51am UTC](https://discourse.julialang.org/t/switched-from-python-to-julia-for-speed-but-its-not-faster/45904 "2020-09-02T02:51:43Z")

</div>

I have a Python script where the major speed hurdle is a single function in the statsmodels package. However, it seems that if I use PyCall to use the same Python function in Julia, the speed hurdle persists to the same …

---

## [Differentiation method for element-wise "abs"-function applied on "Operation"-types in ModelingToolKit.jl?](https://discourse.julialang.org/t/differentiation-method-for-element-wise-abs-function-applied-on-operation-types-in-modelingtoolkit-jl/45867)

<div class="topic-metadata">

**Author:** [@luis\_munoz](https://discourse.julialang.org/u/luis_munoz)\
**Replies:** 4\
**Last updated:** [September 2, 2020, 2:22am UTC](https://discourse.julialang.org/t/differentiation-method-for-element-wise-abs-function-applied-on-operation-types-in-modelingtoolkit-jl/45867 "2020-09-02T02:22:18Z")

</div>

Hi, I am trying to apply ModelingToolkit.sparsejacobian() to my differential function including element-wise calls of the absolute function abs(). How can I appropriately define the derivative of abs() to be used with t…

---

## [How to locate in which package a certain function belongs](https://discourse.julialang.org/t/how-to-locate-in-which-package-a-certain-function-belongs/45915)

<div class="topic-metadata">

**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 3\
**Last updated:** [September 2, 2020, 12:48am UTC](https://discourse.julialang.org/t/how-to-locate-in-which-package-a-certain-function-belongs/45915 "2020-09-02T00:48:07Z")

</div>

How to locate in which package a certain function belongs. For example I am interested in finding the package for the function integrate\_ODE, which is shown in an example of the Pluto package \[Interactivity\]

---

## [How to clean strings?](https://discourse.julialang.org/t/how-to-clean-strings/45917)

<div class="topic-metadata">

**Author:** [@Brad\_Carman](https://discourse.julialang.org/u/Brad_Carman)\
**Replies:** 5\
**Last updated:** [September 2, 2020, 12:32am UTC](https://discourse.julialang.org/t/how-to-clean-strings/45917 "2020-09-02T00:32:27Z")

</div>

I have 2 strings that as a human appear exactly the same, but Julia sees 2 different strings. test1 = raw"C:\\Program Files\\MATLAB\\R2019a" test2 = raw"C:\\Program Files\\MATLAB\\R2019a" test1 == test2 #julia says this is f…

---

## [Understanding relative performance of (returning vs. mutating vs. both) functions](https://discourse.julialang.org/t/understanding-relative-performance-of-returning-vs-mutating-vs-both-functions/45862)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 9\
**Last updated:** [September 1, 2020, 10:29pm UTC](https://discourse.julialang.org/t/understanding-relative-performance-of-returning-vs-mutating-vs-both-functions/45862 "2020-09-01T22:29:23Z")

</div>

I’m trying to choose the fastest among the following 3 functions: using Test, BenchmarkTools function Mut!(x::Array{Int64,2},y::Array{Int64,1}) map!(z-\>z\*2,x,x) y .= vec(reduce(+,x,dims=1)) end function MutRet(…

---

## [Revival of AWS.jl](https://discourse.julialang.org/t/revival-of-aws-jl/45922)

<div class="topic-metadata">

**Author:** [@mattBrzezinski](https://discourse.julialang.org/u/mattBrzezinski)\
**Replies:** 0\
**Last updated:** [September 1, 2020, 9:29pm UTC](https://discourse.julialang.org/t/revival-of-aws-jl/45922 "2020-09-01T21:29:38Z")

</div>

Overview I’m excited to finally announced the release of AWS.jl@1.0.0 today! The revival of this package is meant to take the state of using AWS in Julia to the next level. AWS.jl is a direct replacement to the low-leve…

---

## [Kuramoto-like coupled oscillators in DifferentialEquations.jl](https://discourse.julialang.org/t/kuramoto-like-coupled-oscillators-in-differentialequations-jl/45873)

<div class="topic-metadata">

**Author:** [@VMHidalgo](https://discourse.julialang.org/u/VMHidalgo)\
**Replies:** 5\
**Last updated:** [September 1, 2020, 8:30pm UTC](https://discourse.julialang.org/t/kuramoto-like-coupled-oscillators-in-differentialequations-jl/45873 "2020-09-01T20:30:55Z")

</div>

Hi I’d like to know how to implement a Kuramoto-like (coupled nonlinear oscillators) system in DifferentialEquations.jl. If you are familiar with this stuff, I am trying to produce a system proposed by Matthew,Mirollo a…

---

## [Non-sorted SparseMatrixCSC](https://discourse.julialang.org/t/non-sorted-sparsematrixcsc/37133)

<div class="topic-metadata">

**Author:** [@MaximilianJHuber](https://discourse.julialang.org/u/MaximilianJHuber)\
**Replies:** 23\
**Last updated:** [September 1, 2020, 8:04pm UTC](https://discourse.julialang.org/t/non-sorted-sparsematrixcsc/37133 "2020-09-01T20:04:27Z")

</div>

Adding elements to a sparse one after another is slow due to sorting, allocating and copying. Is there another AbstractSparseMatrix that is more friendly to bit-by-bit construction. Or even one that can leverage the fact…

---

## [Problem installing IJulia](https://discourse.julialang.org/t/problem-installing-ijulia/45544)

<div class="topic-metadata">

**Author:** [@ndgallo](https://discourse.julialang.org/u/ndgallo)\
**Replies:** 6\
**Last updated:** [September 1, 2020, 7:50pm UTC](https://discourse.julialang.org/t/problem-installing-ijulia/45544 "2020-09-01T19:50:13Z")

</div>

Hi, I’m brand new to Julia and was following one of the JuliaAcademy courses but unfortunately have run into a hiccup quite quickly. When I try to install IJulia in terminal, I receive the following System Error. (@v1.…

---

## [How do I get an almost "normal" normal distribution?](https://discourse.julialang.org/t/how-do-i-get-an-almost-normal-normal-distribution/45863)

<div class="topic-metadata">

**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 7\
**Last updated:** [September 1, 2020, 6:02pm UTC](https://discourse.julialang.org/t/how-do-i-get-an-almost-normal-normal-distribution/45863 "2020-09-01T18:02:33Z")

</div>

Sorry for the “normal” normal :sweat\_smile:. What I mean is that I need a Gaussian distribution with a slight change. I need to include a factor \\xi, such as the density distribution below I don’t need the best perfor…

---

## [Input from System Clock](https://discourse.julialang.org/t/input-from-system-clock/45898)

<div class="topic-metadata">

**Author:** [@onButtonUp](https://discourse.julialang.org/u/onButtonUp)\
**Replies:** 4\
**Last updated:** [September 1, 2020, 6:01pm UTC](https://discourse.julialang.org/t/input-from-system-clock/45898 "2020-09-01T18:01:13Z")

</div>

Not sure if I am approaching a project from the wrong direction, but I wonder how the system clock may be used as an input to a Julia program. Say, every 50mS I want a signal (like an interrupt) to start a process. I don…

---

## [How to get a function to print stuff with REPL-like formatting](https://discourse.julialang.org/t/how-to-get-a-function-to-print-stuff-with-repl-like-formatting/45877)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 5\
**Last updated:** [September 1, 2020, 5:33pm UTC](https://discourse.julialang.org/t/how-to-get-a-function-to-print-stuff-with-repl-like-formatting/45877 "2020-09-01T17:33:27Z")

</div>

Sometimes it’s easier if what gets printed by a function looks nice (like in the REPL): function printout(x) println("x is: ",x) end Ex 1. Beautiful formatting that can be instantly read and understood: check = ra…

---

## [ANN: Scratch.jl -- package specific mutable data containers](https://discourse.julialang.org/t/ann-scratch-jl-package-specific-mutable-data-containers/45855)

<div class="topic-metadata">

**Author:** [@fredrikekre](https://discourse.julialang.org/u/fredrikekre)\
**Replies:** 2\
**Last updated:** [September 1, 2020, 5:14pm UTC](https://discourse.julialang.org/t/ann-scratch-jl-package-specific-mutable-data-containers/45855 "2020-09-01T17:14:40Z")

</div>

Scratch.jl Scratch.jl implements package-specific namespaced mutable data scratch spaces/containers. The spaces can contain datasets, text, binaries, or any other data that is convenient to store in a package-specific lo…

---

## [Local scope in for loops AGAIN](https://discourse.julialang.org/t/local-scope-in-for-loops-again/45899)

<div class="topic-metadata">

**Author:** [@sandeep\_prakash](https://discourse.julialang.org/u/sandeep_prakash)\
**Replies:** 11\
**Last updated:** [September 1, 2020, 4:47pm UTC](https://discourse.julialang.org/t/local-scope-in-for-loops-again/45899 "2020-09-01T16:47:50Z")

</div>

Hi, New to Julia from MATLAB. I’ve been reading up on the local variable scope rules in Julia, but fail to understand the behaviour i see in the following example Example code u0 = 10 #The global scope variable …

---

## [Problem with package "OhMyREPL" in startup.jl file](https://discourse.julialang.org/t/problem-with-package-ohmyrepl-in-startup-jl-file/45824)

<div class="topic-metadata">

**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 2\
**Last updated:** [August 31, 2020, 2:03pm UTC](https://discourse.julialang.org/t/problem-with-package-ohmyrepl-in-startup-jl-file/45824 "2020-08-31T14:03:31Z")

</div>

Hello From the link Dynamic REPL prompt? we develop this script for startup.jl #OhMyREPL try @eval using OhMyREPL @eval using Crayons @eval using Dates catch e @warn e end using Dates…

---

## [Change output destination with JUNO. Main document vs REPL](https://discourse.julialang.org/t/change-output-destination-with-juno-main-document-vs-repl/18313)

<div class="topic-metadata">

**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 12\
**Last updated:** [September 1, 2020, 4:10pm UTC](https://discourse.julialang.org/t/change-output-destination-with-juno-main-document-vs-repl/18313 "2020-09-01T16:10:32Z")

</div>

Hello. When using Juno how can I control where the output of a command is produced? Some commands such as 1+1 produce an output on the right side of the line on the main document,inlined. Some other output the result …

---

## [How to get a GLM where formula is programmatically generated](https://discourse.julialang.org/t/how-to-get-a-glm-where-formula-is-programmatically-generated/43519)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 3\
**Last updated:** [September 1, 2020, 3:56pm UTC](https://discourse.julialang.org/t/how-to-get-a-glm-where-formula-is-programmatically-generated/43519 "2020-09-01T15:56:39Z")

</div>

I have a DataFrame and need to build a model where the predictors follow some naming scheme. For the example data below, suppose the scheme is “!=y”: using DataFrames using GLM data = DataFrame(y=\[22.1,20.1,7.1,9.1,10…

---

## [Speed up in Julia](https://discourse.julialang.org/t/speed-up-in-julia/45864)

<div class="topic-metadata">

**Author:** [@Nova](https://discourse.julialang.org/u/Nova)\
**Replies:** 11\
**Last updated:** [September 1, 2020, 2:58pm UTC](https://discourse.julialang.org/t/speed-up-in-julia/45864 "2020-09-01T14:58:35Z")

</div>

I have a question to figure out how to improve the performance of my code in Julia. I have a function that takes N seconds to be finished. I want to optimize the function to achieve a better performance. To do this, I g…

---

## [Vscode: wrapping git commit messages](https://discourse.julialang.org/t/vscode-wrapping-git-commit-messages/45820)

<div class="topic-metadata">

**Author:** [@tim.holy](https://discourse.julialang.org/u/tim.holy)\
**Replies:** 2\
**Last updated:** [September 1, 2020, 1:44pm UTC](https://discourse.julialang.org/t/vscode-wrapping-git-commit-messages/45820 "2020-09-01T13:44:54Z")

</div>

Is it just me, or is there really no easy way to have vscode automatically apply word-wrap to commit messages? This is one of the few things I find deeply annoying about vscode, so if there’s a good fix I’d love to hear …

---

## [Linear Complementarity Problem. Non-obsolete package?](https://discourse.julialang.org/t/linear-complementarity-problem-non-obsolete-package/39665)

<div class="topic-metadata">

**Author:** [@juliauser](https://discourse.julialang.org/u/juliauser)\
**Replies:** 14\
**Last updated:** [September 1, 2020, 12:33pm UTC](https://discourse.julialang.org/t/linear-complementarity-problem-non-obsolete-package/39665 "2020-09-01T12:33:19Z")

</div>

I was wondering which is a fast and easy to use package for a LCP problem. The examples using Complementarity I found give me errors (things like curly brackets were used) and PATHSolver requires a license (I cannot get …

[Previous page](https://discourse.julialang.org/latest.md?page=1641)

[Next page](https://discourse.julialang.org/latest.md?page=1643)