# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1292

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

**Page:** 1293

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## [DDE running result is different from the result in Matlab](https://discourse.julialang.org/t/dde-running-result-is-different-from-the-result-in-matlab/66769)

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**Author:** [@Liwei17](https://discourse.julialang.org/u/Liwei17)\
**Replies:** 2\
**Last updated:** [August 21, 2021, 10:20am UTC](https://discourse.julialang.org/t/dde-running-result-is-different-from-the-result-in-matlab/66769 "2021-08-21T10:20:27Z")

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I’m using DifferentialEquations.jl package to solve a delay differential equations problem. However, the result is different from what I got in Matlab. Can anybody tell me which part goes wrong? \>\< This is my code in J…

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## [Solving ODE parameters using experimental data with control inputs](https://discourse.julialang.org/t/solving-ode-parameters-using-experimental-data-with-control-inputs/66614)

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**Author:** [@Anthony](https://discourse.julialang.org/u/Anthony)\
**Replies:** 20\
**Last updated:** [August 21, 2021, 6:44am UTC](https://discourse.julialang.org/t/solving-ode-parameters-using-experimental-data-with-control-inputs/66614 "2021-08-21T06:44:28Z")

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I am trying to solve for parameters of a simple differential equation that looks like this: \\dot T = aT + bD + c where T is collected experimentally and D is the known control input. I’m trying to solve for the parame…

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## [How to define a file, \`include()\`, and variables globally during \`Distributed.jl\` for loop](https://discourse.julialang.org/t/how-to-define-a-file-include-and-variables-globally-during-distributed-jl-for-loop/66764)

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**Author:** [@colebrookson](https://discourse.julialang.org/u/colebrookson)\
**Replies:** 0\
**Last updated:** [August 21, 2021, 5:21am UTC](https://discourse.julialang.org/t/how-to-define-a-file-include-and-variables-globally-during-distributed-jl-for-loop/66764 "2021-08-21T05:21:24Z")

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Hi All, So I’m trying to set up a script to run in parallel on my machine and I’m having some trouble. I’m still new to doing distributed jobs in Julia, so any advice is appreciated :slight\_smile: What I want to have h…

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## [leftjoin(df\_A,df\_B, on = :Date) UndefVarError: leftjoin not defined](https://discourse.julialang.org/t/leftjoin-df-a-df-b-on-date-undefvarerror-leftjoin-not-defined/66690)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 17\
**Last updated:** [August 21, 2021, 2:17am UTC](https://discourse.julialang.org/t/leftjoin-df-a-df-b-on-date-undefvarerror-leftjoin-not-defined/66690 "2021-08-21T02:17:40Z")

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My once functioning code, which uses DataFrames, suddenly throws an error at the line leftjoin(df\_A,df\_B, on = :Date) I have no idea why leftjoin is suddenly not recognized. What am I missing?

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## [Avoid memory allocation in passing arrays](https://discourse.julialang.org/t/avoid-memory-allocation-in-passing-arrays/66560)

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**Author:** [@Frisus95](https://discourse.julialang.org/u/Frisus95)\
**Replies:** 14\
**Last updated:** [August 21, 2021, 2:14am UTC](https://discourse.julialang.org/t/avoid-memory-allocation-in-passing-arrays/66560 "2021-08-21T02:14:46Z")

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Hello everyone, I’m trying to figure out how to avoid unnecessary memory allocation in the following example (I’m using the Tullio package, but I think it also applies in more general contexts): using Tullio using Loop…

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## [Can this contraction run faster without memory allocation?](https://discourse.julialang.org/t/can-this-contraction-run-faster-without-memory-allocation/66761)

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**Author:** [@Frisus95](https://discourse.julialang.org/u/Frisus95)\
**Replies:** 0\
**Last updated:** [August 21, 2021, 1:51am UTC](https://discourse.julialang.org/t/can-this-contraction-run-faster-without-memory-allocation/66761 "2021-08-21T01:51:42Z")

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Hello everyone! is it possible to make this code run faster and not allocate more memory than necessary? julia\> function funza(Tensor, indices) result = 0.0 for i = 1:5 T1 = Tensor\[indices\[1\],in…

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## [Modifying a rectangle from an image and replacing the original rectangle with the modified one](https://discourse.julialang.org/t/modifying-a-rectangle-from-an-image-and-replacing-the-original-rectangle-with-the-modified-one/66711)

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**Author:** [@banksiaboy](https://discourse.julialang.org/u/banksiaboy)\
**Replies:** 4\
**Last updated:** [August 21, 2021, 12:05am UTC](https://discourse.julialang.org/t/modifying-a-rectangle-from-an-image-and-replacing-the-original-rectangle-with-the-modified-one/66711 "2021-08-21T00:05:05Z")

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I have a rectangular subset of an image which I’ve done some processing on, I want to put the modified subset into exactly the same spot in the original image. I am struggling to find the Julia vocabulary to search in t…

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## [Why putting partial array in the function argument and update it actually does not change the array?](https://discourse.julialang.org/t/why-putting-partial-array-in-the-function-argument-and-update-it-actually-does-not-change-the-array/66754)

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**Author:** [@CRquantum](https://discourse.julialang.org/u/CRquantum)\
**Replies:** 13\
**Last updated:** [August 20, 2021, 11:33pm UTC](https://discourse.julialang.org/t/why-putting-partial-array-in-the-function-argument-and-update-it-actually-does-not-change-the-array/66754 "2021-08-20T23:33:12Z")

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A small question. I put the 1st column of an array in the function argument, and update its first value to 100.0. However the array does not really change, why? Z = \[1.0 2.0; 3.0 4.0\] function f(theta::Array{Float64,1…

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## [New language written in Julia](https://discourse.julialang.org/t/new-language-written-in-julia/66744)

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**Author:** [@dgpdx](https://discourse.julialang.org/u/dgpdx)\
**Replies:** 2\
**Last updated:** [August 20, 2021, 10:10pm UTC](https://discourse.julialang.org/t/new-language-written-in-julia/66744 "2021-08-20T22:10:08Z")

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I’m implementing a concatenative language (CL) in Julia called jacl. At present jacl is in its infancy with lots of work remaining. I welcome suggestions for improvement and even collaboration. If you’re interested in ja…

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## [Repeatedly summing displaced array, lots of allocations and slow](https://discourse.julialang.org/t/repeatedly-summing-displaced-array-lots-of-allocations-and-slow/66710)

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**Author:** [@Ruvi\_Lecamwasam](https://discourse.julialang.org/u/Ruvi_Lecamwasam)\
**Replies:** 5\
**Last updated:** [August 20, 2021, 8:22pm UTC](https://discourse.julialang.org/t/repeatedly-summing-displaced-array-lots-of-allocations-and-slow/66710 "2021-08-20T20:22:33Z")

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I have two one-dimensional arrays of length nT: greensfunc is an array of Float64, X is an array of Float64 zeros. I want to repeatedly multiply greensfunc by a random number, and add the result to X, but for each sum…

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## [ANN: Plotly library and doc updates](https://discourse.julialang.org/t/ann-plotly-library-and-doc-updates/66747)

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**Author:** [@sglyon](https://discourse.julialang.org/u/sglyon)\
**Replies:** 0\
**Last updated:** [August 20, 2021, 8:10pm UTC](https://discourse.julialang.org/t/ann-plotly-library-and-doc-updates/66747 "2021-08-20T20:10:08Z")

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Hello Julians! Over the past couple months we’ve made a ton of updates to the PlotlyBase.jl and PlotlyJS.jl packages We have a whole slew of new features including faceted charts, support for ColorSchemes.jl, templat…

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## [Experiences using JuMP with Gurobi cloud](https://discourse.julialang.org/t/experiences-using-jump-with-gurobi-cloud/66732)

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**Author:** [@Akatz](https://discourse.julialang.org/u/Akatz)\
**Replies:** 1\
**Last updated:** [August 20, 2021, 8:19pm UTC](https://discourse.julialang.org/t/experiences-using-jump-with-gurobi-cloud/66732 "2021-08-20T20:19:51Z")

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Hi, Anyone have experience or feedback on using JuMP with gurobi instant cloud?

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## [Why the global variable is not updated even already initialized and included in all modules?](https://discourse.julialang.org/t/why-the-global-variable-is-not-updated-even-already-initialized-and-included-in-all-modules/66704)

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**Author:** [@CRquantum](https://discourse.julialang.org/u/CRquantum)\
**Replies:** 12\
**Last updated:** [August 20, 2021, 7:44pm UTC](https://discourse.julialang.org/t/why-the-global-variable-is-not-updated-even-already-initialized-and-included-in-all-modules/66704 "2021-08-20T19:44:51Z")

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Sorry for another stupid question again. First of all, I am not proud of using global variables. My question is very simple. Three modules, A, B, and C, they are in A.jl, B.jl, C.jl. I have defined an array called mus…

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## [Makie: mismatch between LaTeX and non-LaTeX font sizes](https://discourse.julialang.org/t/makie-mismatch-between-latex-and-non-latex-font-sizes/66734)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 11\
**Last updated:** [August 20, 2021, 7:34pm UTC](https://discourse.julialang.org/t/makie-mismatch-between-latex-and-non-latex-font-sizes/66734 "2021-08-20T19:34:03Z")

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I have created the following example with CairoMakie.jl: using CairoMakie, LaTeXStrings xs = 0.0:0.01:2.0 lines(xs, sin.(π.\*xs), axis=(title=L"\\sin{x}",)) According to the documentation, the font sizes for title an…

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## [Makie stacked bar chart legends & labels inside axis](https://discourse.julialang.org/t/makie-stacked-bar-chart-legends-labels-inside-axis/66706)

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**Author:** [@bicepjai](https://discourse.julialang.org/u/bicepjai)\
**Replies:** 1\
**Last updated:** [August 20, 2021, 6:58pm UTC](https://discourse.julialang.org/t/makie-stacked-bar-chart-legends-labels-inside-axis/66706 "2021-08-20T18:58:44Z")

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How to place legend for stacked bar chart inside an axis. This can save lot of space on plots. How to place labels when drawing stacked bar chart Sample code can be found in makie examples here using CairoMakie tbl =…

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## [MLJ fit and predict](https://discourse.julialang.org/t/mlj-fit-and-predict/66720)

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**Author:** [@Vishal\_Sharma1](https://discourse.julialang.org/u/Vishal_Sharma1)\
**Replies:** 1\
**Last updated:** [August 20, 2021, 6:51pm UTC](https://discourse.julialang.org/t/mlj-fit-and-predict/66720 "2021-08-20T18:51:03Z")

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Through MLJ’s fit and predict methods, we get the machine trained and then use it for test sample prediction respectively. What is the best way to get the training sample prediction? If I use predict on the training sa…

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## [Makie plot not updating on key press](https://discourse.julialang.org/t/makie-plot-not-updating-on-key-press/66697)

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**Author:** [@mkoculak](https://discourse.julialang.org/u/mkoculak)\
**Replies:** 2\
**Last updated:** [August 20, 2021, 6:46pm UTC](https://discourse.julialang.org/t/makie-plot-not-updating-on-key-press/66697 "2021-08-20T18:46:49Z")

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I am trying to make a simple plot updating on a keypress. I get the “step” to update when I press the keys, but the plot stays the same. I can’t seem to find any examples of such a case. It is probably something simple…

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## [How do findall ,findmax ,findmin, argmax, argmin work on SparseArrays/SparseMatrixCSC](https://discourse.julialang.org/t/how-do-findall-findmax-findmin-argmax-argmin-work-on-sparsearrays-sparsematrixcsc/66735)

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**Author:** [@yewalenikhil65](https://discourse.julialang.org/u/yewalenikhil65)\
**Replies:** 3\
**Last updated:** [August 20, 2021, 5:37pm UTC](https://discourse.julialang.org/t/how-do-findall-findmax-findmin-argmax-argmin-work-on-sparsearrays-sparsematrixcsc/66735 "2021-08-20T17:37:49Z")

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Do findall findmax ,findmin, argmax, argmin work on SparseArrays by convert sparse to Matrix type before doing operations on these functions? If yes, is the computational cost too much of converting?

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## [Printing a prompt and waiting for input](https://discourse.julialang.org/t/printing-a-prompt-and-waiting-for-input/66696)

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**Author:** [@dgpdx](https://discourse.julialang.org/u/dgpdx)\
**Replies:** 7\
**Last updated:** [August 20, 2021, 5:18pm UTC](https://discourse.julialang.org/t/printing-a-prompt-and-waiting-for-input/66696 "2021-08-20T17:18:55Z")

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I’m trying to print a prompt, then leave the cursor on the same line for user input. But when I execute println("\> ") the cursor moves to the next line. How can I do this?

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## [Updating packages' version in a pluto notebook](https://discourse.julialang.org/t/updating-packages-version-in-a-pluto-notebook/66705)

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**Author:** [@gianmariomanca](https://discourse.julialang.org/u/gianmariomanca)\
**Replies:** 1\
**Last updated:** [August 20, 2021, 4:50pm UTC](https://discourse.julialang.org/t/updating-packages-version-in-a-pluto-notebook/66705 "2021-08-20T16:50:49Z")

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I was initially skeptical of Pluto’s package management (slowed down things for me) until I had to share a complex Pluto notebook with a colleague the afternoon before leaving for a trip. With a quick call he was able to…

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## [\[WIP\] Using Faust in Julia](https://discourse.julialang.org/t/wip-using-faust-in-julia/66271)

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**Author:** [@sletz](https://discourse.julialang.org/u/sletz)\
**Replies:** 4\
**Last updated:** [August 20, 2021, 3:52pm UTC](https://discourse.julialang.org/t/wip-using-faust-in-julia/66271 "2021-08-20T15:52:27Z")

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Faust (Functional Audio Stream) is a functional programming language for sound synthesis and audio processing with a strong focus on the design of synthesizers, musical instruments, audio effects, etc. Faust targets high…

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## [Makie: figure resolution in inches](https://discourse.julialang.org/t/makie-figure-resolution-in-inches/66716)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 6\
**Last updated:** [August 20, 2021, 3:07pm UTC](https://discourse.julialang.org/t/makie-figure-resolution-in-inches/66716 "2021-08-20T15:07:05Z")

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How do I create a figure whose size is given in inches instead of pixels? fig = Figure(res = ?) I’ve searched the Makie.jl docs but I really didn’t find out how. Search keywords resolution and inches did not yield usef…

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## [Equivalent Julia and Fortran syntax](https://discourse.julialang.org/t/equivalent-julia-and-fortran-syntax/62027)

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**Author:** [@Beliavsky](https://discourse.julialang.org/u/Beliavsky)\
**Replies:** 9\
**Last updated:** [August 20, 2021, 3:04pm UTC](https://discourse.julialang.org/t/equivalent-julia-and-fortran-syntax/62027 "2021-08-20T15:04:53Z")

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Since Fortran is the language I know best, and since Julia and modern Fortran are similar in some ways, I have made some notes on equivalent syntax in Julia and Fortran, also posted on GitHub. Below, the Julia syntax app…

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## [Understanding Stackoverflow errors and recursion in Julia](https://discourse.julialang.org/t/understanding-stackoverflow-errors-and-recursion-in-julia/66647)

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**Author:** [@dannofthursday](https://discourse.julialang.org/u/dannofthursday)\
**Replies:** 1\
**Last updated:** [August 20, 2021, 1:51pm UTC](https://discourse.julialang.org/t/understanding-stackoverflow-errors-and-recursion-in-julia/66647 "2021-08-20T13:51:53Z")

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I am going through the very excellent Algorithms course, in Coursera, and am trying to implement all of the problems in Julia, so that I can learn about algorithms and practice with Julia. A couple of weeks back, we were…

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## [DataFrames: Most efficient way to compute statistics on multiple/nested subgroups](https://discourse.julialang.org/t/dataframes-most-efficient-way-to-compute-statistics-on-multiple-nested-subgroups/66714)

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**Author:** [@told](https://discourse.julialang.org/u/told)\
**Replies:** 2\
**Last updated:** [August 20, 2021, 1:33pm UTC](https://discourse.julialang.org/t/dataframes-most-efficient-way-to-compute-statistics-on-multiple-nested-subgroups/66714 "2021-08-20T13:33:29Z")

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I have a dataset with population statistics similar to this: using DataFrames #make a dummy data set df = DataFrame(date = \[1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2\], age\_group = \[1, 2, 2, 3, 4, 4, 5,…

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## [No docs for figure attributes in Makie](https://discourse.julialang.org/t/no-docs-for-figure-attributes-in-makie/66683)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 12\
**Last updated:** [August 20, 2021, 12:12pm UTC](https://discourse.julialang.org/t/no-docs-for-figure-attributes-in-makie/66683 "2021-08-20T12:12:16Z")

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Hi, guys. I have decided to give Makie.jl a try and prepare the plots for my paper in it. Unfortunately, I got stuck at the very beginning. Skimming over docs, I noticed that there is no list of the figure attributes …

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## [Help with LightGraphs.jl](https://discourse.julialang.org/t/help-with-lightgraphs-jl/66663)

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**Author:** [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Replies:** 6\
**Last updated:** [August 20, 2021, 10:13am UTC](https://discourse.julialang.org/t/help-with-lightgraphs-jl/66663 "2021-08-20T10:13:24Z")

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Hello, I am trying to move away from the R package iGraph to LightGraphs.jl but am having difficulty. I have a food web where each species is a node and a link connects it to another species (node) - this is translated…

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## [Comparing the Diffeq.jl Euler stepper with a by-hand Euler stepper](https://discourse.julialang.org/t/comparing-the-diffeq-jl-euler-stepper-with-a-by-hand-euler-stepper/66691)

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**Author:** [@zornsllama](https://discourse.julialang.org/u/zornsllama)\
**Replies:** 5\
**Last updated:** [August 20, 2021, 9:52am UTC](https://discourse.julialang.org/t/comparing-the-diffeq-jl-euler-stepper-with-a-by-hand-euler-stepper/66691 "2021-08-20T09:52:02Z")

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I am trying to understand the behavior of Diffeq.jl in a toy example, with the eventual goal of implementing networks of integrate-and-fire neurons. These questions are probably very basic, but any clarification would be…

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## [Cannot install packages - \`no space left on device (ENOSPC)\`](https://discourse.julialang.org/t/cannot-install-packages-no-space-left-on-device-enospc/66665)

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**Author:** [@sim](https://discourse.julialang.org/u/sim)\
**Replies:** 6\
**Last updated:** [August 20, 2021, 9:38am UTC](https://discourse.julialang.org/t/cannot-install-packages-no-space-left-on-device-enospc/66665 "2021-08-20T09:38:36Z")

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Hello, I recently installed Julia 1.6.2 on my remote machine, added julia to PATH, it works. Then I wanted to add some packages (like Plots, Makie, Flux, Franklin), and everytime I do add PackageName I get the followi…

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## [How to avoid \`using MyPackage\` in every doctest?](https://discourse.julialang.org/t/how-to-avoid-using-mypackage-in-every-doctest/66675)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 12\
**Last updated:** [August 20, 2021, 9:35am UTC](https://discourse.julialang.org/t/how-to-avoid-using-mypackage-in-every-doctest/66675 "2021-08-20T09:35:39Z")

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I have a jldoctest entry which is: julia\> using CellListMap julia\> box = Box(\[100,70,130\],12) Box{OrthorhombicCell, 3, Float64, 9} unit cell matrix: \[100.0 0.0 0.0; 0.0 70.0 0.0; 0.0 0.0 130.0\] cutoff: 12.0 numbe…

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