# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1592

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

**Page:** 1593

---

## [Change Optimization Level in VS Code?](https://discourse.julialang.org/t/change-optimization-level-in-vs-code/48966)

<div class="topic-metadata">

**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 1\
**Last updated:** [October 25, 2020, 2:53pm UTC](https://discourse.julialang.org/t/change-optimization-level-in-vs-code/48966 "2020-10-25T14:53:02Z")

</div>

Hi! I changed from Atom to VS Code, and there is a setting option in Atom which allows one to change the optimization level used in Julia when compiling code. Where do I find this setting in Julia? I am using Windows K…

---

## [Https://www.anaconda.com blocked](https://discourse.julialang.org/t/https-www-anaconda-com-blocked/48969)

<div class="topic-metadata">

**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 1\
**Last updated:** [October 25, 2020, 2:22pm UTC](https://discourse.julialang.org/t/https-www-anaconda-com-blocked/48969 "2020-10-25T14:22:48Z")

</div>

My current network has https://www.anaconda.com blocked. But I have managed to download, from main/win-64, the file matplotlib-base-3.3.2-py38hba9282a\_0.tar.bz2 Is there any way to activate it, from Julia, using the C…

---

## [Principal Components Analysis on datasets with missing data](https://discourse.julialang.org/t/principal-components-analysis-on-datasets-with-missing-data/48962)

<div class="topic-metadata">

**Author:** [@clibassi](https://discourse.julialang.org/u/clibassi)\
**Replies:** 5\
**Last updated:** [October 25, 2020, 2:16pm UTC](https://discourse.julialang.org/t/principal-components-analysis-on-datasets-with-missing-data/48962 "2020-10-25T14:16:47Z")

</div>

Hey all - I’m sort of new to principal components analysis - especially in Julia, but I’ve been digging through @nassarhuda’s great Dimensionality Reduction notebook but am running into an issue because the data I’m wor…

---

## [Convert dataframe to runnable Julia code?](https://discourse.julialang.org/t/convert-dataframe-to-runnable-julia-code/48971)

<div class="topic-metadata">

**Author:** [@StatisticalMouse](https://discourse.julialang.org/u/StatisticalMouse)\
**Replies:** 16\
**Last updated:** [October 25, 2020, 2:14pm UTC](https://discourse.julialang.org/t/convert-dataframe-to-runnable-julia-code/48971 "2020-10-25T14:14:11Z")

</div>

How would I convert a dataframe to Julia code? I have a dataframe containing these in a notebook, and I want Julia code that when run, produces a dataframe with the same contents. 10 rows × 12 columns PassengerId Survi…

---

## [inUsing Julia for analysing eye tracking data, anyone doing something like that?](https://discourse.julialang.org/t/inusing-julia-for-analysing-eye-tracking-data-anyone-doing-something-like-that/29115)

<div class="topic-metadata">

**Author:** [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Replies:** 3\
**Last updated:** [October 25, 2020, 12:37pm UTC](https://discourse.julialang.org/t/inusing-julia-for-analysing-eye-tracking-data-anyone-doing-something-like-that/29115 "2020-10-25T12:37:36Z")

</div>

My colleague from university work on VR and need some framework for analysis data from eye tracking. They have big files with char and numbers and they just need to make some analysis of them. For what I understand not t…

---

## [Segfault while loading images in multiple threads](https://discourse.julialang.org/t/segfault-while-loading-images-in-multiple-threads/48878)

<div class="topic-metadata">

**Author:** [@sigmike](https://discourse.julialang.org/u/sigmike)\
**Replies:** 14\
**Last updated:** [October 25, 2020, 11:57am UTC](https://discourse.julialang.org/t/segfault-while-loading-images-in-multiple-threads/48878 "2020-10-25T11:57:12Z")

</div>

Hello, I tried to process images in parallel but the load operation results in a Segmentation Fault. Is loading images not thread safe? using Images, FileIO Threads.@threads for path in readdir("img"; join=true) load…

---

## [Should callers of iterate assert ::Union{Nothing,Tuple{Any,Any}}](https://discourse.julialang.org/t/should-callers-of-iterate-assert-union-nothing-tuple-any-any/48973)

<div class="topic-metadata">

**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 0\
**Last updated:** [October 25, 2020, 10:33am UTC](https://discourse.julialang.org/t/should-callers-of-iterate-assert-union-nothing-tuple-any-any/48973 "2020-10-25T10:33:17Z")

</div>

Because callers of iterate just destructure or use indexes, all kinds of hard to understand bugs can result from incorrectly implemented iterate methods. Eg struct Foo N::Int end function Base.iterate(foo::Foo, i =…

---

## [Can structs have static fields?](https://discourse.julialang.org/t/can-structs-have-static-fields/48970)

<div class="topic-metadata">

**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 1\
**Last updated:** [October 25, 2020, 9:40am UTC](https://discourse.julialang.org/t/can-structs-have-static-fields/48970 "2020-10-25T09:40:46Z")

</div>

Does Julia have something similar to static class members in C++, whose values are shared across all objects of the class? If not, is there a good way to emulate it? I don’t want it to be a constant global variable, sinc…

---

## [Corporate Grants for Volunteer Hours](https://discourse.julialang.org/t/corporate-grants-for-volunteer-hours/48888)

<div class="topic-metadata">

**Author:** [@avik](https://discourse.julialang.org/u/avik)\
**Replies:** 2\
**Last updated:** [October 25, 2020, 9:23am UTC](https://discourse.julialang.org/t/corporate-grants-for-volunteer-hours/48888 "2020-10-25T09:23:39Z")

</div>

As you know the Julia project (as well as JuMP and SciML) are fiscally sponsored by NumFOCUS, an US based charity. The funds we collect via NumFOCUS helps pay for the ongoing expenses of the project, such as some of our …

---

## [ForwardDiff with function using broadcasting](https://discourse.julialang.org/t/forwarddiff-with-function-using-broadcasting/48959)

<div class="topic-metadata">

**Author:** [@mjhoshea](https://discourse.julialang.org/u/mjhoshea)\
**Replies:** 1\
**Last updated:** [October 25, 2020, 8:41am UTC](https://discourse.julialang.org/t/forwarddiff-with-function-using-broadcasting/48959 "2020-10-25T08:41:46Z")

</div>

I am trying to use ForwardDiff to check some analytic gradients for a mse loss and logistic hypothesis function. So just looking at the loss of a single data point we have mse(x) = (1/2)\*((y - logistic.(transpose(x)\*w))…

---

## [Update Conda vs update Julia 1.5.2](https://discourse.julialang.org/t/update-conda-vs-update-julia-1-5-2/48926)

<div class="topic-metadata">

**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 2\
**Last updated:** [October 25, 2020, 6:38am UTC](https://discourse.julialang.org/t/update-conda-vs-update-julia-1-5-2/48926 "2020-10-25T06:38:47Z")

</div>

After successfully performing the Coda update: using Conda \[ Info: Precompiling Conda \[8f4d0f93-b110-5947-807f-2305c1781a2d\] julia\> Conda.ROOTENV "C:\\\\Users\\\\user\\\\.julia\\\\conda\\\\3" julia\> Conda.update() \[ Info: Runni…

---

## [Myid() does not work as expected in @everywhere](https://discourse.julialang.org/t/myid-does-not-work-as-expected-in-everywhere/48964)

<div class="topic-metadata">

**Author:** [@ggarza](https://discourse.julialang.org/u/ggarza)\
**Replies:** 5\
**Last updated:** [October 25, 2020, 6:16am UTC](https://discourse.julialang.org/t/myid-does-not-work-as-expected-in-everywhere/48964 "2020-10-25T06:16:17Z")

</div>

I’m running the following code in Visual Studio Code: using Distributed, Plots addprocs(3) @everywhere begin using Plots x = \[0, 300\] y = \[0, 300\] p = scatter(x, y) title!(p, "Process: $(myid())") …

---

## [Improving perfomance on nested loops](https://discourse.julialang.org/t/improving-perfomance-on-nested-loops/48864)

<div class="topic-metadata">

**Author:** [@k945](https://discourse.julialang.org/u/k945)\
**Replies:** 5\
**Last updated:** [October 25, 2020, 5:29am UTC](https://discourse.julialang.org/t/improving-perfomance-on-nested-loops/48864 "2020-10-25T05:29:00Z")

</div>

I am trying to improve the performance of script that I am converting from python. To my knowledge, I have: written a kernel function, preallocated my output and accessed memory in order. While I have improved the scrip…

---

## [Performance when using DifferentialEquations.solve repeatedly inside a loop](https://discourse.julialang.org/t/performance-when-using-differentialequations-solve-repeatedly-inside-a-loop/48961)

<div class="topic-metadata">

**Author:** [@ash](https://discourse.julialang.org/u/ash)\
**Replies:** 2\
**Last updated:** [October 25, 2020, 12:47am UTC](https://discourse.julialang.org/t/performance-when-using-differentialequations-solve-repeatedly-inside-a-loop/48961 "2020-10-25T00:47:30Z")

</div>

I am using the split step method to solve the following equation: i \\frac{\\partial \\psi}{\\partial t} = -\\frac{1}{2} \\frac{\\partial^2 \\psi}{\\partial x^2} - |\\psi|^2\\psi + i \\alpha\\left(\\frac{\\partial^3 \\psi}{\\partial x^…

---

## [Stuck on a NamedTuple problem](https://discourse.julialang.org/t/stuck-on-a-namedtuple-problem/48835)

<div class="topic-metadata">

**Author:** [@a5vzener](https://discourse.julialang.org/u/a5vzener)\
**Replies:** 9\
**Last updated:** [October 24, 2020, 11:34pm UTC](https://discourse.julialang.org/t/stuck-on-a-namedtuple-problem/48835 "2020-10-24T23:34:27Z")

</div>

I think a NamedTuple can do what I want but I can’t quite figure out the syntax. Can someone help me with this bit of runnable code? function nameparts(v) t = split(v,':') length(t) \< 2 ? (nothing,t\[1\]) : (t\[1\],…

---

## [\[ANN\] GeoStats.jl v0.18](https://discourse.julialang.org/t/ann-geostats-jl-v0-18/48951)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 0\
**Last updated:** [October 24, 2020, 8:16pm UTC](https://discourse.julialang.org/t/ann-geostats-jl-v0-18/48951 "2020-10-24T20:16:34Z")

</div>

GeoStats.jl v0.18 includes better support for nested spatial correlation and geometric anisotropy. Given spatial correlation functions, a nested correlation can be obtained via a linear model: julia\> γ₁ = GaussianVario…

---

## [ANN: Automatic test-case reduction](https://discourse.julialang.org/t/ann-automatic-test-case-reduction/17700)

<div class="topic-metadata">

**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 1\
**Last updated:** [October 24, 2020, 9:20pm UTC](https://discourse.julialang.org/t/ann-automatic-test-case-reduction/17700 "2020-10-24T21:20:54Z")

</div>

Hi all, C-Reduce is a tool that takes a large C, C++, or OpenCL file that has a property of interest (such as triggering a compiler bug) and automatically produces a much smaller C/C++ file that has the same property. …

---

## ["Traits" which may be defined on types or values?](https://discourse.julialang.org/t/traits-which-may-be-defined-on-types-or-values/48919)

<div class="topic-metadata">

**Author:** [@evanfields](https://discourse.julialang.org/u/evanfields)\
**Replies:** 10\
**Last updated:** [October 24, 2020, 6:08pm UTC](https://discourse.julialang.org/t/traits-which-may-be-defined-on-types-or-values/48919 "2020-10-24T18:08:22Z")

</div>

I’m trying to learn about \[Holy\] traits for the first time. It seems that in the classic implementation, an object’s traitfulness depends only on that object’s type, not value. For example, maybe I want to classify certa…

---

## [Slow Deployment of Flux Mode](https://discourse.julialang.org/t/slow-deployment-of-flux-mode/48945)

<div class="topic-metadata">

**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 5\
**Last updated:** [October 24, 2020, 5:29pm UTC](https://discourse.julialang.org/t/slow-deployment-of-flux-mode/48945 "2020-10-24T17:29:10Z")

</div>

Hi. I have a trained Flux model which I wish to apply repeatedly using separate calls from an external program. Since Julia1.5 (and corresponding Flux version) every time the function is called, the line using Flux r…

---

## [Fixing and freeing variables o JuMP](https://discourse.julialang.org/t/fixing-and-freeing-variables-o-jump/48838)

<div class="topic-metadata">

**Author:** [@baprata](https://discourse.julialang.org/u/baprata)\
**Replies:** 13\
**Last updated:** [October 24, 2020, 4:45pm UTC](https://discourse.julialang.org/t/fixing-and-freeing-variables-o-jump/48838 "2020-10-24T16:45:49Z")

</div>

I am studying a combinatorial optimization problem with JuMP and Gurobi. I need to fix some decision variables for a given number of iterations or a given time limit. After that, I would like to unfix these variables pre…

---

## [Bug with \`@.\`](https://discourse.julialang.org/t/bug-with/48940)

<div class="topic-metadata">

**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 3\
**Last updated:** [October 24, 2020, 4:39pm UTC](https://discourse.julialang.org/t/bug-with/48940 "2020-10-24T16:39:10Z")

</div>

I think I’ve found a bug with the @. macro julia\> function foo(;x = 0, y = 8) return x end foo (generic function with 1 method) julia\> a = \[1, 2, 3\]; b = \[4, 5, 6\]; julia\> foo(; x = @. a \* b, y = b) ERRO…

---

## [How to connect to Cassandra db from Julia](https://discourse.julialang.org/t/how-to-connect-to-cassandra-db-from-julia/48947)

<div class="topic-metadata">

**Author:** [@trl\_bin](https://discourse.julialang.org/u/trl_bin)\
**Replies:** 0\
**Last updated:** [October 24, 2020, 4:29pm UTC](https://discourse.julialang.org/t/how-to-connect-to-cassandra-db-from-julia/48947 "2020-10-24T16:29:09Z")

</div>

Hello, I am a newbie to julia. I want to access to Cassandra db from julia. I already tried this cqldriver(https://github.com/r3tex/CQLdriver.jl) by adding the package as Pkg.add(“CQLdriver”) but cannot use. Am I doing i…

---

## [Exploring package contents](https://discourse.julialang.org/t/exploring-package-contents/48937)

<div class="topic-metadata">

**Author:** [@Gert-Jan\_van\_der\_Kam](https://discourse.julialang.org/u/Gert-Jan_van_der_Kam)\
**Replies:** 9\
**Last updated:** [October 24, 2020, 3:35pm UTC](https://discourse.julialang.org/t/exploring-package-contents/48937 "2020-10-24T15:35:08Z")

</div>

Hi I’m getting into Julia and I don’t yet understamd how I can find out what I can type. For instance I want to read CSV, so I add the CSV package, but then how do I know how to use it? In C# I would either open a NuGet…

---

## [Read numbers from stdin and display a realtime plot](https://discourse.julialang.org/t/read-numbers-from-stdin-and-display-a-realtime-plot/48943)

<div class="topic-metadata">

**Author:** [@NightMachinary](https://discourse.julialang.org/u/NightMachinary)\
**Replies:** 0\
**Last updated:** [October 24, 2020, 4:05pm UTC](https://discourse.julialang.org/t/read-numbers-from-stdin-and-display-a-realtime-plot/48943 "2020-10-24T16:05:27Z")

</div>

I want to read streaming numbers from stdin, and create a plot from them (x being the line number and y the number itself) which updates itself as new data is available. What’s the best approach here? (I also don’t want…

---

## [Control flow of shell command Pipe()](https://discourse.julialang.org/t/control-flow-of-shell-command-pipe/48915)

<div class="topic-metadata">

**Author:** [@Donut\_Meepo](https://discourse.julialang.org/u/Donut_Meepo)\
**Replies:** 5\
**Last updated:** [October 24, 2020, 3:04pm UTC](https://discourse.julialang.org/t/control-flow-of-shell-command-pipe/48915 "2020-10-24T15:04:39Z")

</div>

Hi, I am trying to process a large amount of shell command output that I want to do it line by line. The following code is what I have right now. The while loop will not terminate. I could do that by checking process\_run…

---

## [Ccall performance](https://discourse.julialang.org/t/ccall-performance/48872)

<div class="topic-metadata">

**Author:** [@j\_tanu](https://discourse.julialang.org/u/j_tanu)\
**Replies:** 16\
**Last updated:** [October 24, 2020, 2:37pm UTC](https://discourse.julialang.org/t/ccall-performance/48872 "2020-10-24T14:37:25Z")

</div>

Hi, I am doing a matrix-matrix multiplication A(12870\*11440)\*B(11440\*11440) using mkl\_dgemm library. In c language, The whole calculation takes about 20 sec but if I call the mkl\_dgemm using Julia’s ccall it takes 42.27…

---

## [Symbol to variable in a macro](https://discourse.julialang.org/t/symbol-to-variable-in-a-macro/48924)

<div class="topic-metadata">

**Author:** [@Philippe\_Maincon1](https://discourse.julialang.org/u/Philippe_Maincon1)\
**Replies:** 6\
**Last updated:** [October 24, 2020, 1:49pm UTC](https://discourse.julialang.org/t/symbol-to-variable-in-a-macro/48924 "2020-10-24T13:49:23Z")

</div>

An easy question. I have asked it some time back and got a good answer, but cannot find back to it, not on Discourse, not in the manual, and not in my code… I want to write a macro to generate code like getfield(vari,…

---

## [Polar decomposition of a matrix](https://discourse.julialang.org/t/polar-decomposition-of-a-matrix/48830)

<div class="topic-metadata">

**Author:** [@danuzco](https://discourse.julialang.org/u/danuzco)\
**Replies:** 14\
**Last updated:** [October 24, 2020, 1:41pm UTC](https://discourse.julialang.org/t/polar-decomposition-of-a-matrix/48830 "2020-10-24T13:41:49Z")

</div>

I need to compute polar decomposition (PD) of matrices https://en.wikipedia.org/wiki/Polar\_decomposition. I tried to install this package https://github.com/weijianzhang/PolarFact.jl, but I’m getting this error: ERROR:…

---

## [Knet on powerpc64le platform?](https://discourse.julialang.org/t/knet-on-powerpc64le-platform/48149)

<div class="topic-metadata">

**Author:** [@jdad](https://discourse.julialang.org/u/jdad)\
**Replies:** 13\
**Last updated:** [October 24, 2020, 1:23pm UTC](https://discourse.julialang.org/t/knet-on-powerpc64le-platform/48149 "2020-10-24T13:23:28Z")

</div>

I am trying to use Knet on a supercomputer using powerpc64le nodes with NVidia TeslaV100 GPUs. But I am not able to compile it (so no use it, with or without GPU access). It seems the Knet version installed (1.4.2) wan…

---

## [Dataframes and categorical, good style?](https://discourse.julialang.org/t/dataframes-and-categorical-good-style/48903)

<div class="topic-metadata">

**Author:** [@StatisticalMouse](https://discourse.julialang.org/u/StatisticalMouse)\
**Replies:** 5\
**Last updated:** [October 24, 2020, 12:24pm UTC](https://discourse.julialang.org/t/dataframes-and-categorical-good-style/48903 "2020-10-24T12:24:47Z")

</div>

I’m trying to write some Kaggle Titanic code and to show context first: datadirectory = "../data/titanic/" train\_df = CSV.read(datadirectory \* "train.csv") describe(train\_df) variable mean min median max nunique nmissi…

[Previous page](https://discourse.julialang.org/latest.md?page=1591)

[Next page](https://discourse.julialang.org/latest.md?page=1593)