# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1409

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

**Page:** 1410

---

## [Dataframe parses differently if data is passed in columns vs as an array](https://discourse.julialang.org/t/dataframe-parses-differently-if-data-is-passed-in-columns-vs-as-an-array/60130)

<div class="topic-metadata">

**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 3\
**Last updated:** [April 28, 2021, 8:35am UTC](https://discourse.julialang.org/t/dataframe-parses-differently-if-data-is-passed-in-columns-vs-as-an-array/60130 "2021-04-28T08:35:25Z")

</div>

Is it expected behavior that the DataFrames constructor will return different results if the data is passed in by column or as a matrix? In the former case the type of the column is more precisely inferred. In the latter…

---

## [Constraint nonlinear problem](https://discourse.julialang.org/t/constraint-nonlinear-problem/60033)

<div class="topic-metadata">

**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 7\
**Last updated:** [April 28, 2021, 8:04am UTC](https://discourse.julialang.org/t/constraint-nonlinear-problem/60033 "2021-04-28T08:04:23Z")

</div>

I have tried GalacticOptim.jl but I did not manage to get the constraints to work. using GalacticOptim, Optim using Plots rosenbrock(x, p) = (p\[1\] - x\[1\])^2 + p\[2\] \* (x\[2\] - x\[1\]^2)^2 x0 = zeros(2) p = \[1.0, 100.0\] c…

---

## [How do I "wrap" a table object (in Luxor) around a torus (donut)?](https://discourse.julialang.org/t/how-do-i-wrap-a-table-object-in-luxor-around-a-torus-donut/59892)

<div class="topic-metadata">

**Author:** [@AndresCasillas](https://discourse.julialang.org/u/AndresCasillas)\
**Replies:** 5\
**Last updated:** [April 28, 2021, 7:35am UTC](https://discourse.julialang.org/t/how-do-i-wrap-a-table-object-in-luxor-around-a-torus-donut/59892 "2021-04-28T07:35:41Z")

</div>

I´m currently working on a Jupyter file and with Julia version 1.5.3 on a Windows computer, using Luxor. I have an array of arrays and a function (dibujar\_matriz) which creates a table based on the entries of each array. …

---

## [Warning: could not download https://pkg.julialang.org/registries](https://discourse.julialang.org/t/warning-could-not-download-https-pkg-julialang-org-registries/60147)

<div class="topic-metadata">

**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 1\
**Last updated:** [April 28, 2021, 7:08am UTC](https://discourse.julialang.org/t/warning-could-not-download-https-pkg-julialang-org-registries/60147 "2021-04-28T07:08:16Z")

</div>

I have managed to install some packages on Julia 1.6.1. But I get the following alert: Warning: could not download https://pkg.julialang.org/registries (@v1.6) pkg\> add ColorSchemes Updating registry at \`C:\\Users\\…

---

## [Unable to use PyPlot either in Jupyter notebook or in terminal](https://discourse.julialang.org/t/unable-to-use-pyplot-either-in-jupyter-notebook-or-in-terminal/60126)

<div class="topic-metadata">

**Author:** [@KK\_JuliaNoob](https://discourse.julialang.org/u/KK_JuliaNoob)\
**Replies:** 2\
**Last updated:** [April 28, 2021, 5:12am UTC](https://discourse.julialang.org/t/unable-to-use-pyplot-either-in-jupyter-notebook-or-in-terminal/60126 "2021-04-28T05:12:25Z")

</div>

I am on a Macbook pro with Big Sur, and I recently switched to Julia 1.6 When I tried to use the PyPlot package from a jupyter notebook, it keeps resetting the Julia kernel, and is unusable. Other Julia packages work fi…

---

## [Is it possible to do a simple example of using Arrow.jl to pass data from/to Python?](https://discourse.julialang.org/t/is-it-possible-to-do-a-simple-example-of-using-arrow-jl-to-pass-data-from-to-python/60146)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 3\
**Last updated:** [April 28, 2021, 5:08am UTC](https://discourse.julialang.org/t/is-it-possible-to-do-a-simple-example-of-using-arrow-jl-to-pass-data-from-to-python/60146 "2021-04-28T05:08:17Z")

</div>

Say I am using PyCall.jl to start a python session. Can I receive an arrow vector from python without having to write it to disk? What’s the mechanism to do so? A simple MWE would be highly appreciated! Also, if I call…

---

## [Expected 72X speedup, observed 1.1X](https://discourse.julialang.org/t/expected-72x-speedup-observed-1-1x/60071)

<div class="topic-metadata">

**Author:** [@PhilipDLoewen](https://discourse.julialang.org/u/PhilipDLoewen)\
**Replies:** 5\
**Last updated:** [April 28, 2021, 4:50am UTC](https://discourse.julialang.org/t/expected-72x-speedup-observed-1-1x/60071 "2021-04-28T04:50:41Z")

</div>

I dreamed up a simple-looking task that I thought multithreading could accelerate. Running the file below (I named it threadbench.jl) proved me wrong: with 72 cores and 72 threads, the timings are not appreciably better …

---

## [\[ANN\] Quantikz.jl v1 for drawing circuits (including in-browser demos)](https://discourse.julialang.org/t/ann-quantikz-jl-v1-for-drawing-circuits-including-in-browser-demos/59911)

<div class="topic-metadata">

**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 0\
**Last updated:** [April 24, 2021, 1:55am UTC](https://discourse.julialang.org/t/ann-quantikz-jl-v1-for-drawing-circuits-including-in-browser-demos/59911 "2021-04-24T01:55:32Z")

</div>

Demo at quantikz.krastanov.org. Library at github.com/Krastanov/Quantikz. Quantikz.jl now supports qubits, ancillas, classical bits, and arbitrary gates and measurements, conditional or not on both qubits and classical …

---

## [\`Chain\` vs \`foldl\` in Flux.jl](https://discourse.julialang.org/t/chain-vs-foldl-in-flux-jl/60136)

<div class="topic-metadata">

**Author:** [@dbg](https://discourse.julialang.org/u/dbg)\
**Replies:** 2\
**Last updated:** [April 28, 2021, 12:31am UTC](https://discourse.julialang.org/t/chain-vs-foldl-in-flux-jl/60136 "2021-04-28T00:31:01Z")

</div>

I am new to both ML and Julia, so this might be a silly question. I am trying to use foldl instead of Chain to create a model with multiple layers, but I am not able to train the model created using foldl. Does anyone kn…

---

## [Saving unicodeplots() to txt with color](https://discourse.julialang.org/t/saving-unicodeplots-to-txt-with-color/60069)

<div class="topic-metadata">

**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 3\
**Last updated:** [April 27, 2021, 9:34pm UTC](https://discourse.julialang.org/t/saving-unicodeplots-to-txt-with-color/60069 "2021-04-27T21:34:59Z")

</div>

This is the solution I didn’t know I needed for quick and dirty hpc plotting. However, they only show up monochrome in #SBATCH --output. Therefore, I tried the following to explicitly save them and neither approach wor…

---

## [Using DrWatson.jl with Slurm: Best practice tipps](https://discourse.julialang.org/t/using-drwatson-jl-with-slurm-best-practice-tipps/40352)

<div class="topic-metadata">

**Author:** [@volkerkarle](https://discourse.julialang.org/u/volkerkarle)\
**Replies:** 9\
**Last updated:** [April 27, 2021, 9:08pm UTC](https://discourse.julialang.org/t/using-drwatson-jl-with-slurm-best-practice-tipps/40352 "2021-04-27T21:08:37Z")

</div>

Dear folks, Following my last question, I am now trying to set up dr.watson.jl for my routines on a cluster. I wonder if someone has experience on this matter? For running a job the following things happen: I have a j…

---

## [\[ANN\] OpenQASM.jl - the OpenQASM parser for Julia](https://discourse.julialang.org/t/ann-openqasm-jl-the-openqasm-parser-for-julia/60129)

<div class="topic-metadata">

**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 1\
**Last updated:** [April 27, 2021, 9:04pm UTC](https://discourse.julialang.org/t/ann-openqasm-jl-the-openqasm-parser-for-julia/60129 "2021-04-27T21:04:17Z")

</div>

I’m excited to announce the OpenQASM parser in its 2.0 version: GitHub - QuantumBFS/OpenQASM.jl: Parsers and Tools for OpenQASM This package provides the functionality for parsing QASM scripts for Yao ecosystem, but you…

---

## [\[ANN\] TypeDBClient.jl - interface to the TypeDB Knowledge Graph](https://discourse.julialang.org/t/ann-typedbclient-jl-interface-to-the-typedb-knowledge-graph/59492)

<div class="topic-metadata">

**Author:** [@mks](https://discourse.julialang.org/u/mks)\
**Replies:** 2\
**Last updated:** [April 27, 2021, 8:48pm UTC](https://discourse.julialang.org/t/ann-typedbclient-jl-interface-to-the-typedb-knowledge-graph/59492 "2021-04-27T20:48:20Z")

</div>

Hello, we would like to announce a package that we are working on for the last 6 months or so. It’s called GraknClient.jl and is a client to the Grakn Knowledge Graph Database. It is still work in progress, so do not e…

---

## [Advice for parallel computation](https://discourse.julialang.org/t/advice-for-parallel-computation/60087)

<div class="topic-metadata">

**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 6\
**Last updated:** [April 27, 2021, 8:44pm UTC](https://discourse.julialang.org/t/advice-for-parallel-computation/60087 "2021-04-27T20:44:29Z")

</div>

Hi, I am trying to solve a big PDE, and I want to parallelize a finite difference. I am seeking some advice on how to do this. At some point I do the following using PDEPackage # struct that contains the parameters pd…

---

## [Mutating fields in StructArrays](https://discourse.julialang.org/t/mutating-fields-in-structarrays/60106)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 11\
**Last updated:** [April 27, 2021, 8:20pm UTC](https://discourse.julialang.org/t/mutating-fields-in-structarrays/60106 "2021-04-27T20:20:18Z")

</div>

I am starting to use StructArrays in a package, and the benefits clearly outweigh the costs. However, there is one thing that I have, for the moment, to let go, which is the mutation of fields using the most natural synt…

---

## [Unexpected recompilation](https://discourse.julialang.org/t/unexpected-recompilation/60000)

<div class="topic-metadata">

**Author:** [@Peter\_Adelman](https://discourse.julialang.org/u/Peter_Adelman)\
**Replies:** 1\
**Last updated:** [April 27, 2021, 7:32pm UTC](https://discourse.julialang.org/t/unexpected-recompilation/60000 "2021-04-27T19:32:04Z")

</div>

I will front-run this post with the disclaimer that it is going to be impossible to provide a MWE here, because if I could provide a MWE then I would be able to solve this problem. I am using multiple dispatch and the s…

---

## [Plots.jl horizontal and vertical labels across subplots in grid layout](https://discourse.julialang.org/t/plots-jl-horizontal-and-vertical-labels-across-subplots-in-grid-layout/60113)

<div class="topic-metadata">

**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 5\
**Last updated:** [April 27, 2021, 7:23pm UTC](https://discourse.julialang.org/t/plots-jl-horizontal-and-vertical-labels-across-subplots-in-grid-layout/60113 "2021-04-27T19:23:55Z")

</div>

using Plots n\_from = 2 n\_to = 3 froms = \[Plots.fakedata(100) for i = 1:n\_from\] tos = \[Plots.fakedata(100) for i = 1:n\_to\] gl = grid(n\_from + 1 , n\_to + 1) p = plot(;layout = gl, aspect\_ratio = 1.0) # setup subplots f…

---

## [Huge difference in performance between two programmes](https://discourse.julialang.org/t/huge-difference-in-performance-between-two-programmes/60116)

<div class="topic-metadata">

**Author:** [@encendre](https://discourse.julialang.org/u/encendre)\
**Replies:** 7\
**Last updated:** [April 27, 2021, 7:02pm UTC](https://discourse.julialang.org/t/huge-difference-in-performance-between-two-programmes/60116 "2021-04-27T19:02:24Z")

</div>

I’m sorry for the not very descriptive title but I couldn’t find a better way to phrase it I have two similar programmes with a huge difference in performance let function useless() end @time let s = 0 for n i…

---

## [Plotting Series of Shapes](https://discourse.julialang.org/t/plotting-series-of-shapes/60108)

<div class="topic-metadata">

**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 6\
**Last updated:** [April 27, 2021, 6:51pm UTC](https://discourse.julialang.org/t/plotting-series-of-shapes/60108 "2021-04-27T18:51:27Z")

</div>

I’d like to plot a series of shapes. I create a vector of shape objects and plot directly. Unlike other series types, each shape is plotted with a different color by default. My hope is that they would all be the same co…

---

## [Optimizing user-defined objective functions with no direct expression](https://discourse.julialang.org/t/optimizing-user-defined-objective-functions-with-no-direct-expression/60096)

<div class="topic-metadata">

**Author:** [@Fathya.Salih](https://discourse.julialang.org/u/Fathya.Salih)\
**Replies:** 1\
**Last updated:** [April 27, 2021, 6:48pm UTC](https://discourse.julialang.org/t/optimizing-user-defined-objective-functions-with-no-direct-expression/60096 "2021-04-27T18:48:40Z")

</div>

I have a Monte Carlo simulation that takes in a set of variables x1, x2, etc. and returns a number of counters that can be used to calculate the actual objective function f() I wanted to use JuMP to optimize the dimensi…

---

## [VSCode debugging while maintaining workspace](https://discourse.julialang.org/t/vscode-debugging-while-maintaining-workspace/60119)

<div class="topic-metadata">

**Author:** [@davide-f](https://discourse.julialang.org/u/davide-f)\
**Replies:** 0\
**Last updated:** [April 27, 2021, 5:50pm UTC](https://discourse.julialang.org/t/vscode-debugging-while-maintaining-workspace/60119 "2021-04-27T17:50:37Z")

</div>

Dear Community, I recently switched from Juno to VSCode and I was wondering how I can use the debugging in Juno-like style so that when I run a file, the existing workspace is read. Currently, when I run a configuratio…

---

## [Dealing with NaN's](https://discourse.julialang.org/t/dealing-with-nans/60086)

<div class="topic-metadata">

**Author:** [@statspy](https://discourse.julialang.org/u/statspy)\
**Replies:** 21\
**Last updated:** [April 27, 2021, 4:59pm UTC](https://discourse.julialang.org/t/dealing-with-nans/60086 "2021-04-27T16:59:01Z")

</div>

Hello, I am trying to filter a dataframe to exclude NaN’a values but not working so far. How can i deal with NaN’s? I am trying: filter(!isnan(df.salary)) What are my options to deal with NaN’s? Thanks

---

## [Invitation to contribute - book](https://discourse.julialang.org/t/invitation-to-contribute-book/50066)

<div class="topic-metadata">

**Author:** [@paula.birocchi](https://discourse.julialang.org/u/paula.birocchi)\
**Replies:** 6\
**Last updated:** [April 27, 2021, 4:43pm UTC](https://discourse.julialang.org/t/invitation-to-contribute-book/50066 "2021-04-27T16:43:04Z")

</div>

Hi everyone, We are looking for someone that would like to contribute in writing about Julia as a Program for Model Output Visualization in our book: Introduction to Ocean Numerical Modeling. The idea is to give an over…

---

## [Problems with GR.plot, but may be environment related](https://discourse.julialang.org/t/problems-with-gr-plot-but-may-be-environment-related/32423)

<div class="topic-metadata">

**Author:** [@Andrzej\_Ceglowski](https://discourse.julialang.org/u/Andrzej_Ceglowski)\
**Replies:** 5\
**Last updated:** [April 27, 2021, 2:19pm UTC](https://discourse.julialang.org/t/problems-with-gr-plot-but-may-be-environment-related/32423 "2021-04-27T14:19:26Z")

</div>

After an Atom restart I cannot get plots to run without error messages. The following REPL code and errors are indicative: julia\> plot(rand(10)) Error showing value of type Plots.Plot{Plots.GRBackend}: ERROR: SystemE…

---

## [Domain error at the integrand using QuadGK](https://discourse.julialang.org/t/domain-error-at-the-integrand-using-quadgk/60076)

<div class="topic-metadata">

**Author:** [@leopdsf](https://discourse.julialang.org/u/leopdsf)\
**Replies:** 1\
**Last updated:** [April 27, 2021, 3:20pm UTC](https://discourse.julialang.org/t/domain-error-at-the-integrand-using-quadgk/60076 "2021-04-27T15:20:26Z")

</div>

Hello, everyone! I am trying to perform the numerical integration of the function \\tanh^2(z) using QuadGK.jl with the following code using Plots using QuadGK k(z) = tanh(z)^2 plot(k) Q = quadgk(k,-Inf,Inf) but when I …

---

## [Explanation of Error related to memory](https://discourse.julialang.org/t/explanation-of-error-related-to-memory/60111)

<div class="topic-metadata">

**Author:** [@Sumanshekhar17](https://discourse.julialang.org/u/Sumanshekhar17)\
**Replies:** 0\
**Last updated:** [April 27, 2021, 3:19pm UTC](https://discourse.julialang.org/t/explanation-of-error-related-to-memory/60111 "2021-04-27T15:19:31Z")

</div>

Hi all, I am learning GPU programming and wanted to know what maximum grid size my machine can resolve so I went for a 1000x1000x500 grid and I got this error. Can you please explain what it is saying in easy words ERR…

---

## [Details about Julia's Garbage Collector, Reference Counting?](https://discourse.julialang.org/t/details-about-julias-garbage-collector-reference-counting/18021)

<div class="topic-metadata">

**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 4\
**Last updated:** [April 27, 2021, 2:58pm UTC](https://discourse.julialang.org/t/details-about-julias-garbage-collector-reference-counting/18021 "2021-04-27T14:58:16Z")

</div>

Where can I get more details about Julia’s Garbage Collector? I think it uses the “Automatic Reference Counting” method but I’d like to know more details about how it has been implemented and the expected roadmap, what …

---

## [Error broadcasting string getproperty using StructArrays](https://discourse.julialang.org/t/error-broadcasting-string-getproperty-using-structarrays/60109)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 4\
**Last updated:** [April 27, 2021, 2:42pm UTC](https://discourse.julialang.org/t/error-broadcasting-string-getproperty-using-structarrays/60109 "2021-04-27T14:42:33Z")

</div>

Another issue with my migration to StructArrays. There is one problem I don’t understand when trying to broadcast a function that gets a property and this property, specifically, is of type String. For example: julia\> s…

---

## [QBase.jl v0.2.0 Release](https://discourse.julialang.org/t/qbase-jl-v0-2-0-release/59962)

<div class="topic-metadata">

**Author:** [@bdoolittle](https://discourse.julialang.org/u/bdoolittle)\
**Replies:** 6\
**Last updated:** [April 27, 2021, 2:20pm UTC](https://discourse.julialang.org/t/qbase-jl-v0-2-0-release/59962 "2021-04-27T14:20:57Z")

</div>

Hi Everyone, I’m excited to introduce QBase.jl as a base library for quantum information. The goal of QBase.jl is to provide a lightweight computational framework for quantum mechanics. This Julia package provides: V…

---

## [How to reach a function definition](https://discourse.julialang.org/t/how-to-reach-a-function-definition/60102)

<div class="topic-metadata">

**Author:** [@akhil\_teja](https://discourse.julialang.org/u/akhil_teja)\
**Replies:** 7\
**Last updated:** [April 27, 2021, 1:59pm UTC](https://discourse.julialang.org/t/how-to-reach-a-function-definition/60102 "2021-04-27T13:59:57Z")

</div>

I was just going through the github repo of Plots.jl and in it I was trying to find the function definition KW (Line number 52: https://github.com/JuliaPlots/Plots.jl/blob/1ceb3a561f5e9f20471636865180d603d09753ed/src/plo…

[Previous page](https://discourse.julialang.org/latest.md?page=1408)

[Next page](https://discourse.julialang.org/latest.md?page=1410)