# Latest **URL:** https://discourse.julialang.org/latest.md?page=1365 [Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md) **Page:** 1366 --- ## [Installing custom packages on JuliaBox](https://discourse.julialang.org/t/installing-custom-packages-on-juliabox/21592)

**Author:** [@xor0110](https://discourse.julialang.org/u/xor0110)\ **Replies:** 0\ **Last updated:** [March 7, 2019, 6:38pm UTC](https://discourse.julialang.org/t/installing-custom-packages-on-juliabox/21592 "2019-03-07T18:38:39Z")

I am trying to install an external package on JuliaBox, is it possible? I couldn’t do it using Pkg.add with my GitHub repo or unzipping an archive. Is this supposed to work? In case so, how do I debug this? --- ## [JuliaBox has officially been sunsetted (as of May 31st)](https://discourse.julialang.org/t/juliabox-has-officially-been-sunsetted-as-of-may-31st/43066)

**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\ **Replies:** 0\ **Last updated:** [July 14, 2020, 4:56pm UTC](https://discourse.julialang.org/t/juliabox-has-officially-been-sunsetted-as-of-may-31st/43066 "2020-07-14T16:56:54Z")

Hey all, JuliaBox is no more. The tutorials that used to live under the Julia Computing org and in the JuliaBox Tutorials repo have been transferred to: https://github.com/JuliaAcademy/JuliaTutorials and the license has… --- ## [What is the easiest way to read ABC notation files in Julia?Example\`\`\`X:1T:Alex](https://discourse.julialang.org/t/what-is-the-easiest-way-to-read-abc-notation-files-in-julia-example-xalex/55880)

**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\ **Replies:** 0\ **Last updated:** [February 23, 2021, 7:42pm UTC](https://discourse.julialang.org/t/what-is-the-easiest-way-to-read-abc-notation-files-in-julia-example-xalex/55880 "2021-02-23T19:42:25Z")

**Author:** [@RoyiAvital](https://discourse.julialang.org/u/RoyiAvital)\ **Replies:** 1\ **Last updated:** [June 10, 2021, 1:30am UTC](https://discourse.julialang.org/t/which-solution-does-return/61902 "2021-06-10T01:30:02Z")

I saw this insightful discussion on Slack (Made some editing for clarity): @baggepinnen : The \\ (Operator) should produce the minimum norm solution if many exist, and that’s what it does. @RoyiAvital : I am not su… --- ## [Logging with custom messages](https://discourse.julialang.org/t/logging-with-custom-messages/62637)

**Author:** [@Enrique](https://discourse.julialang.org/u/Enrique)\ **Replies:** 2\ **Last updated:** [June 10, 2021, 1:27am UTC](https://discourse.julialang.org/t/logging-with-custom-messages/62637 "2021-06-10T01:27:26Z")

Hello Julia community, I read the logging documentation, but I am still struggling to create a custom logger. Basically, what I want to do is to replicate what I do in python, that is, to create a logger on info level, … --- ## [Subtract the Column Wise Mean of a Large Matrix](https://discourse.julialang.org/t/subtract-the-column-wise-mean-of-a-large-matrix/61740)

**Author:** [@RoyiAvital](https://discourse.julialang.org/u/RoyiAvital)\ **Replies:** 0\ **Last updated:** [May 24, 2021, 7:04pm UTC](https://discourse.julialang.org/t/subtract-the-column-wise-mean-of-a-large-matrix/61740 "2021-05-24T19:04:07Z")

As a service to export from a nice discussion (Not by me) in Slack. I need to take a large matrix and subtract the mean columnwise and inplace. Is there a fast way to do this? By columnwise I mean taking the mean o… --- ## [Optim.jl vs scipy.optimize once again](https://discourse.julialang.org/t/optim-jl-vs-scipy-optimize-once-again/61661)

**Author:** [@rht](https://discourse.julialang.org/u/rht)\ **Replies:** 54\ **Last updated:** [June 10, 2021, 12:23am UTC](https://discourse.julialang.org/t/optim-jl-vs-scipy-optimize-once-again/61661 "2021-06-10T00:23:27Z")

I have been using Python’s scipy.optimize.minimize(method="LBFGSB") for my research, and have been looking to speed the code because it doesn’t scale. And so I tried to rewrite my code in Julia using Optim.jl, with Opti… --- ## [Array processing](https://discourse.julialang.org/t/array-processing/62643)

**Author:** [@neophytedave](https://discourse.julialang.org/u/neophytedave)\ **Replies:** 1\ **Last updated:** [June 9, 2021, 8:24pm UTC](https://discourse.julialang.org/t/array-processing/62643 "2021-06-09T20:24:01Z")

Please see Vocabulary/ArrayProcessing - J Wiki. How do Julia and (I suppose) other languages deal with this? --- ## [Choleski Factorization transpose](https://discourse.julialang.org/t/choleski-factorization-transpose/9483)

**Author:** [@Yifan\_Liu](https://discourse.julialang.org/u/Yifan_Liu)\ **Replies:** 6\ **Last updated:** [June 9, 2021, 8:12pm UTC](https://discourse.julialang.org/t/choleski-factorization-transpose/9483 "2021-06-09T20:12:11Z")

I have a Matlab code like this: T = 0.5; NbPas=100; DeltaT=T/NbPas; rho=-0.2; L = chol(\[DeltaT,rho\*DeltaT;rho\*DeltaT,DeltaT\])’; I tried to translate it into Julia code: T = 0.5 NbPas=10… --- ## [JuliaPro bug where screen goes black](https://discourse.julialang.org/t/juliapro-bug-where-screen-goes-black/62640)

**Author:** [@rezabayani](https://discourse.julialang.org/u/rezabayani)\ **Replies:** 1\ **Last updated:** [June 9, 2021, 7:50pm UTC](https://discourse.julialang.org/t/juliapro-bug-where-screen-goes-black/62640 "2021-06-09T19:50:49Z")

I have been using JuliaPro version 1.5.1-4 for a couple weeks now and I encounter this frustrating bug where after working a while on some .jl file, when I try to preview the values of a vector/array/…, the code disappea… --- ## [Iterating over a Tree recursively with Base.iterate](https://discourse.julialang.org/t/iterating-over-a-tree-recursively-with-base-iterate/62512)

**Author:** [@BALLsyman](https://discourse.julialang.org/u/BALLsyman)\ **Replies:** 8\ **Last updated:** [June 9, 2021, 7:42pm UTC](https://discourse.julialang.org/t/iterating-over-a-tree-recursively-with-base-iterate/62512 "2021-06-09T19:42:10Z")

I want to implement Base.iterate so that it can recursively iterate over a tree - it seems to me that gives the best performance. The type is defined as follows: mutable struct node next::Union{node,Missing} fi… --- ## [Unitful + DiffEq + different physical quantities + derivatives?](https://discourse.julialang.org/t/unitful-diffeq-different-physical-quantities-derivatives/62635)

**Author:** [@ggggggggg](https://discourse.julialang.org/u/ggggggggg)\ **Replies:** 1\ **Last updated:** [June 9, 2021, 5:48pm UTC](https://discourse.julialang.org/t/unitful-diffeq-different-physical-quantities-derivatives/62635 "2021-06-09T17:48:30Z")

I’m working on model using Differential Equation that has two state variables, current and temperature. So when using DifferentialEquations.jl I define something like f(du, u, p, t) = ... u is a vector with two element… --- ## [Julia broadcasting notation: period before or after?](https://discourse.julialang.org/t/julia-broadcasting-notation-period-before-or-after/62629)

**Author:** [@Thomas](https://discourse.julialang.org/u/Thomas)\ **Replies:** 10\ **Last updated:** [June 9, 2021, 5:10pm UTC](https://discourse.julialang.org/t/julia-broadcasting-notation-period-before-or-after/62629 "2021-06-09T17:10:42Z")

Why broadcasting for operators like +,\*,^ have a period before and for function like sin have a period after? Silly examples are \[1,2,3\] +. 4 +.(\[1,2,3\],4) \[1,2,3\]==.\[4,5,6\] --- ## [Cholfact not defined](https://discourse.julialang.org/t/cholfact-not-defined/62634)

**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\ **Replies:** 2\ **Last updated:** [June 9, 2021, 5:03pm UTC](https://discourse.julialang.org/t/cholfact-not-defined/62634 "2021-06-09T17:03:15Z")

This is a really dumb question for someone who has been using Julia as long as I have. I see reference (and definition) of the function cholfact but I keep getting the error cholfact not defined even when I load Linea… --- ## [DataFrames groupby() by a column of mutable custom type](https://discourse.julialang.org/t/dataframes-groupby-by-a-column-of-mutable-custom-type/62632)

**Author:** [@AndreLC](https://discourse.julialang.org/u/AndreLC)\ **Replies:** 4\ **Last updated:** [June 9, 2021, 4:44pm UTC](https://discourse.julialang.org/t/dataframes-groupby-by-a-column-of-mutable-custom-type/62632 "2021-06-09T16:44:07Z")

Here is a small example: mutable struct Mystring str::String end using DataFrames strs = \["a","b","a","b"\]; mystrs = Mystring.(strs); df = DataFrame(col\_str=strs, col\_mystr=mystrs); println(df) println(groupby(df… --- ## [Problems in the Gurobi installation](https://discourse.julialang.org/t/problems-in-the-gurobi-installation/62630)

**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\ **Replies:** 7\ **Last updated:** [June 9, 2021, 3:54pm UTC](https://discourse.julialang.org/t/problems-in-the-gurobi-installation/62630 "2021-06-09T15:54:52Z")

Dear all, I have the Gurobi software on my computer. I want to install the Gurobi package in Julia. I have followed the steps on GitHub - jump-dev/Gurobi.jl: Julia interface for Gurobi Optimizer An error message appea… --- ## [How to sample from a truncated distribution given a certain known variance?](https://discourse.julialang.org/t/how-to-sample-from-a-truncated-distribution-given-a-certain-known-variance/62618)

**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\ **Replies:** 2\ **Last updated:** [June 9, 2021, 3:43pm UTC](https://discourse.julialang.org/t/how-to-sample-from-a-truncated-distribution-given-a-certain-known-variance/62618 "2021-06-09T15:43:59Z")

I did notice that when I sample from a truncated distribution the sample variance I get is not the one that I would expect from the distribution, but one “corrected” by the truncation process: using Distributions, Stati… --- ## [Scope of variable in if in loop](https://discourse.julialang.org/t/scope-of-variable-in-if-in-loop/62621)

**Author:** [@Fred\_He](https://discourse.julialang.org/u/Fred_He)\ **Replies:** 8\ **Last updated:** [June 9, 2021, 3:13pm UTC](https://discourse.julialang.org/t/scope-of-variable-in-if-in-loop/62621 "2021-06-09T15:13:02Z")

from my understanding, “if” doesn’t create new scope, so the variable “b” should be local variable in for loop. So why there is an error saying b is not found in the “else” ? function f1(a) for i = 1:2 if i ==1 … --- ## [Any updates on Julia Stipple](https://discourse.julialang.org/t/any-updates-on-julia-stipple/62631)

**Author:** [@bww00](https://discourse.julialang.org/u/bww00)\ **Replies:** 0\ **Last updated:** [June 9, 2021, 2:53pm UTC](https://discourse.julialang.org/t/any-updates-on-julia-stipple/62631 "2021-06-09T14:53:47Z")

I have some need to use julia with oracle, produce a web app and use SAML or AD authenication. Regards Bryan --- ## [Confusion about type stability: functions or methods?](https://discourse.julialang.org/t/confusion-about-type-stability-functions-or-methods/62277)

**Author:** [@fedario](https://discourse.julialang.org/u/fedario)\ **Replies:** 17\ **Last updated:** [June 9, 2021, 2:39pm UTC](https://discourse.julialang.org/t/confusion-about-type-stability-functions-or-methods/62277 "2021-06-09T14:39:03Z")

Hi! Reading the documentation about type stability actually made me unsure if I understood the concept correctly. The documentation states that When possible, it helps to ensure that a function always returns a value… --- ## [Interact.jl, WebIO.jl not working in jupyterlab \>=3](https://discourse.julialang.org/t/interact-jl-webio-jl-not-working-in-jupyterlab-3/62626)

**Author:** [@PaulN](https://discourse.julialang.org/u/PaulN)\ **Replies:** 0\ **Last updated:** [June 9, 2021, 2:21pm UTC](https://discourse.julialang.org/t/interact-jl-webio-jl-not-working-in-jupyterlab-3/62626 "2021-06-09T14:21:48Z")

Although Interact works great for Jupyterlab \<3, I cannot install it for jupyterlab 3.10a11. Here is my current config: from conda: $ jupyter --version jupyter core : 4.6.3 jupyter-notebook : 6.1.4 qtconsole : 4.7.… --- ## [Launching julia code in a server](https://discourse.julialang.org/t/launching-julia-code-in-a-server/62623)

**Author:** [@assia855](https://discourse.julialang.org/u/assia855)\ **Replies:** 1\ **Last updated:** [June 9, 2021, 2:10pm UTC](https://discourse.julialang.org/t/launching-julia-code-in-a-server/62623 "2021-06-09T14:10:07Z")

Hello folks, I’m trying to execute a julia code in a server. It launches but without any output or error, while it was running locally perfectly. Any idea how can I execute files on a server? Thanks in advance. --- ## [Add predictor term to formula](https://discourse.julialang.org/t/add-predictor-term-to-formula/62595)

**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\ **Replies:** 3\ **Last updated:** [June 9, 2021, 1:24pm UTC](https://discourse.julialang.org/t/add-predictor-term-to-formula/62595 "2021-06-09T13:24:09Z")

I have a formula object defined by formula = @formula(y ~ x1 + x2) How can I add another predictor term to that FormulaTerm object after it is created? I tried formula.rhs += Term(:x3) # error push!(formula.rhs, Term… --- ## [One-line debugging](https://discourse.julialang.org/t/one-line-debugging/62612)

**Author:** [@sapo](https://discourse.julialang.org/u/sapo)\ **Replies:** 19\ **Last updated:** [June 9, 2021, 12:58pm UTC](https://discourse.julialang.org/t/one-line-debugging/62612 "2021-06-09T12:58:34Z")

Hello, I’d just like to have a way to easily debug code for terminal-centric people. For instance, right now I have the following situation (which is rather common, though): a test/example script which is added by cal… --- ## [Disable Markers when Plotting with Ribbon](https://discourse.julialang.org/t/disable-markers-when-plotting-with-ribbon/62615)

**Author:** [@IljaK91](https://discourse.julialang.org/u/IljaK91)\ **Replies:** 5\ **Last updated:** [June 9, 2021, 12:06pm UTC](https://discourse.julialang.org/t/disable-markers-when-plotting-with-ribbon/62615 "2021-06-09T12:06:07Z")

Hey everyone, Since the last update I have the following problem. I have a plot including a ribbon using pgfplotsx. It automatically includes markers on the ribbon and on the mean, which I would like to remove both. He… --- ## [How to get started with distributed memory parallel programming?](https://discourse.julialang.org/t/how-to-get-started-with-distributed-memory-parallel-programming/62617)

**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\ **Replies:** 3\ **Last updated:** [June 9, 2021, 10:39am UTC](https://discourse.julialang.org/t/how-to-get-started-with-distributed-memory-parallel-programming/62617 "2021-06-09T10:39:01Z")

I’ve used OpenMP in C/C++ and multi-threading in Julia, but have never learned MPI or other distributed frameworks (excepting submitting arrays of jobs to clusters for trivially parallelizable problems). What is the “Jul… --- ## [Plots, VegaLite, Gadfly and Makie. What is the difference between the Julia visualization packages?](https://discourse.julialang.org/t/plots-vegalite-gadfly-and-makie-what-is-the-difference-between-the-julia-visualization-packages/56024)

**Author:** [@eliascarv](https://discourse.julialang.org/u/eliascarv)\ **Replies:** 19\ **Last updated:** [June 9, 2021, 9:30am UTC](https://discourse.julialang.org/t/plots-vegalite-gadfly-and-makie-what-is-the-difference-between-the-julia-visualization-packages/56024 "2021-06-09T09:30:51Z")

What are the main differences between these packages and how is the current state of each? And, in your opinion, what is the future of data visualization in Julia Language? --- ## [Guidelines for creating a package](https://discourse.julialang.org/t/guidelines-for-creating-a-package/62579)

**Author:** [@pg261](https://discourse.julialang.org/u/pg261)\ **Replies:** 5\ **Last updated:** [June 9, 2021, 9:38am UTC](https://discourse.julialang.org/t/guidelines-for-creating-a-package/62579 "2021-06-09T09:38:10Z")

Hi all, I would like to hear the recommendations for creating a new package “properly”. From my questions, you will see that I don’t fully understand what a package is, especially compared to a (collection of) module(s)… --- ## [Fully parallelized for-loop becomes slower with more threads](https://discourse.julialang.org/t/fully-parallelized-for-loop-becomes-slower-with-more-threads/62614)

**Author:** [@vmuser](https://discourse.julialang.org/u/vmuser)\ **Replies:** 2\ **Last updated:** [June 9, 2021, 9:29am UTC](https://discourse.julialang.org/t/fully-parallelized-for-loop-becomes-slower-with-more-threads/62614 "2021-06-09T09:29:02Z")

Basically the title says it all: I have a for-loop that is fully parallelizable, so all the operations in the loop can be calculated independently. They only need access to the same multidimensional array but I make sure… --- ## [Improving performance in solving SDEProblem](https://discourse.julialang.org/t/improving-performance-in-solving-sdeproblem/62396)

**Author:** [@Frazze](https://discourse.julialang.org/u/Frazze)\ **Replies:** 8\ **Last updated:** [June 9, 2021, 9:00am UTC](https://discourse.julialang.org/t/improving-performance-in-solving-sdeproblem/62396 "2021-06-09T09:00:56Z")

Hi everyone, I’m studying part of the 2D Swift Hohenberg model with an additive noise term, but I’m really new to the SDEProblems so I don’t know if my way to build the model is the best way to solve it. I’ve take a lo… [Previous page](https://discourse.julialang.org/latest.md?page=1364) [Next page](https://discourse.julialang.org/latest.md?page=1366)