# Latest

**URL:** https://discourse.julialang.org/latest.md?page=790

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

**Page:** 791

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## [Announcing new package \`CycPols\`](https://discourse.julialang.org/t/announcing-new-package-cycpols/94142)

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**Author:** [@Jean\_Michel](https://discourse.julialang.org/u/Jean_Michel)\
**Replies:** 0\
**Last updated:** [February 6, 2023, 2:42pm UTC](https://discourse.julialang.org/t/announcing-new-package-cycpols/94142 "2023-02-06T14:42:20Z")

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This package deals with products of Cyclotomic polynomials. Cyclotomic numbers, and cyclotomic polynomials over the rationals or some cyclotomic field, are important in the theories of finite reductive groups and …

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## [How to display an array of UInt8 as a color image](https://discourse.julialang.org/t/how-to-display-an-array-of-uint8-as-a-color-image/93990)

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**Author:** [@Tetane](https://discourse.julialang.org/u/Tetane)\
**Replies:** 8\
**Last updated:** [February 6, 2023, 1:30pm UTC](https://discourse.julialang.org/t/how-to-display-an-array-of-uint8-as-a-color-image/93990 "2023-02-06T13:30:50Z")

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I have a color image represented by an array of UInt8 of size (58638, 22376, 3) that I want to display using imshow from the ImageView package. The RGB channels are contained in the third dimension of the array. I unders…

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## [Sum of an empty array](https://discourse.julialang.org/t/sum-of-an-empty-array/94130)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 1:27pm UTC](https://discourse.julialang.org/t/sum-of-an-empty-array/94130 "2023-02-06T13:27:54Z")

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Hello, I need to calculate the sum of the values in the column of a DataFrame. But it can also be empty. How can I do that? sum(\[\]) gives an long stack trace…

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## [Integration of JuliaFormatter](https://discourse.julialang.org/t/integration-of-juliaformatter/94135)

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**Author:** [@hildebrandecon](https://discourse.julialang.org/u/hildebrandecon)\
**Replies:** 0\
**Last updated:** [February 6, 2023, 12:20pm UTC](https://discourse.julialang.org/t/integration-of-juliaformatter/94135 "2023-02-06T12:20:05Z")

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Dear community, I am struggling with the integration of the JuliaFormatter in VS code. Suppose you have the following code in a file: x = rand(10, 10) sum(x, dims=1) Now, I have activated the auto format on save optio…

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## [How to make a fast first plot with CairoMakie?](https://discourse.julialang.org/t/how-to-make-a-fast-first-plot-with-cairomakie/94120)

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**Author:** [@YH\_Ko](https://discourse.julialang.org/u/YH_Ko)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 7:23am UTC](https://discourse.julialang.org/t/how-to-make-a-fast-first-plot-with-cairomakie/94120 "2023-02-06T07:23:05Z")

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I’m new to Julia language. I have tried to follow data visualization with Makie. However, the time to first plot is too long. (~50sec) 50.087309 seconds (146.21 M allocations: 7.676 GiB, 3.69% gc time, 98.74% compi…

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## [Lead Scoring Not Wasting Everyone's Time](https://discourse.julialang.org/t/lead-scoring-not-wasting-everyones-time/94131)

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**Author:** [@Billpete002](https://discourse.julialang.org/u/Billpete002)\
**Replies:** 0\
**Last updated:** [February 6, 2023, 10:30am UTC](https://discourse.julialang.org/t/lead-scoring-not-wasting-everyones-time/94131 "2023-02-06T10:30:45Z")

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Hi, I’ve created a lead scoring model for sales. The model performs well and passed every check. Now I have a list of probabilities to convert - The sales team doesn’t want to receive low probability leads nor do they w…

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## [Killing long-running thread starting in a web server](https://discourse.julialang.org/t/killing-long-running-thread-starting-in-a-web-server/94128)

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**Author:** [@cjproud](https://discourse.julialang.org/u/cjproud)\
**Replies:** 1\
**Last updated:** [February 6, 2023, 9:54am UTC](https://discourse.julialang.org/t/killing-long-running-thread-starting-in-a-web-server/94128 "2023-02-06T09:54:27Z")

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I’m trying to use Oxygen.jl as an API for a long running ccall. I’m trying to create a toy example where, after 30 seconds, the solver task called by call\_solver() on a new thread is passed InterruptException and stops. …

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## [Specifying size of vector in a struct](https://discourse.julialang.org/t/specifying-size-of-vector-in-a-struct/94125)

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**Author:** [@udax](https://discourse.julialang.org/u/udax)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 9:06am UTC](https://discourse.julialang.org/t/specifying-size-of-vector-in-a-struct/94125 "2023-02-06T09:06:50Z")

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I have a struct like so: struct rpoint pn::Int64 #patch number xyz::Vector{Float64} #coordinates end Note: the xyz field will always be populated with a vector of size 3. I have two questions: Is it true th…

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## [Calling max() atomically on a compound type](https://discourse.julialang.org/t/calling-max-atomically-on-a-compound-type/94028)

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**Author:** [@torrance](https://discourse.julialang.org/u/torrance)\
**Replies:** 8\
**Last updated:** [February 6, 2023, 3:57am UTC](https://discourse.julialang.org/t/calling-max-atomically-on-a-compound-type/94028 "2023-02-06T03:57:06Z")

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I’ve attempted to understand the Julia docs on the newish @atomic stuff multiple times and yet I’m still struggling to fully understand. The docs are actually quite sparse on the topic, and what’s worse is that they poin…

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## [Add .exe in PATH - Julia](https://discourse.julialang.org/t/add-exe-in-path-julia/93954)

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**Author:** [@Students](https://discourse.julialang.org/u/Students)\
**Replies:** 4\
**Last updated:** [February 6, 2023, 3:28am UTC](https://discourse.julialang.org/t/add-exe-in-path-julia/93954 "2023-02-06T03:28:36Z")

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Hi everyone, I am trying to run the “UnderwaterAcoustics” package in Julia. In the installation manual they have provided the following statement: Bellhop will only be available if you have a working copy of bellhop.ex…

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## [Type Stability Help](https://discourse.julialang.org/t/type-stability-help/94114)

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**Author:** [@fft](https://discourse.julialang.org/u/fft)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 3:18am UTC](https://discourse.julialang.org/t/type-stability-help/94114 "2023-02-06T03:18:44Z")

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I am following along with Make Your Own Neural Network by Tariq Rashid. In this work you implement a small neural network by hand. This is for my own benefit and I know if I was doing something for real I should just Flu…

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## [GADFLY Font Change Not Saving](https://discourse.julialang.org/t/gadfly-font-change-not-saving/94044)

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**Author:** [@ChrisVL1](https://discourse.julialang.org/u/ChrisVL1)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 2:25am UTC](https://discourse.julialang.org/t/gadfly-font-change-not-saving/94044 "2023-02-06T02:25:42Z")

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When changing the label font and saving as a PDF, the saved pdf does not display the changed font style. Here’s an example: xs = convert(Vector{Float64}, tsteps) layer2 = layer(x=xs1, y=Euler\_Maruyama1,Geom.line,Them…

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## [Memory leak with @distributed](https://discourse.julialang.org/t/memory-leak-with-distributed/94077)

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**Author:** [@Ralf\_Dietrich](https://discourse.julialang.org/u/Ralf_Dietrich)\
**Replies:** 6\
**Last updated:** [February 6, 2023, 2:15am UTC](https://discourse.julialang.org/t/memory-leak-with-distributed/94077 "2023-02-06T02:15:37Z")

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Hello everyone, I found this sample code somewhere on the internet. It also works, but leaves a memory leak. Where is the error here and how would the code work correctly while maintaining the use of @distributed? usi…

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## [Query Gurobi attributes of JuMP model](https://discourse.julialang.org/t/query-gurobi-attributes-of-jump-model/94113)

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**Author:** [@jacob-roth](https://discourse.julialang.org/u/jacob-roth)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 2:15am UTC](https://discourse.julialang.org/t/query-gurobi-attributes-of-jump-model/94113 "2023-02-06T02:15:33Z")

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I am interested in obtaining particular solution attributes (e.g., DualVio) of my Gurobi model constructed by JuMP. Can I use the Gurobi.jl C interface to query a solved JuMP model to obtain solution quality attributes? …

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## [Julia: \[ Info: Precompiling DifferentialEquations \[0c46a032-eb83-5123-abaf-570d42b7fbaa\] ERROR: LoadError: UndefVarError: undefmatrix not defined](https://discourse.julialang.org/t/julia-info-precompiling-differentialequations-0c46a032-eb83-5123-abaf-570d42b7fbaa-error-loaderror-undefvarerror-undefmatrix-not-defined/94112)

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**Author:** [@qjulia](https://discourse.julialang.org/u/qjulia)\
**Replies:** 1\
**Last updated:** [February 6, 2023, 1:16am UTC](https://discourse.julialang.org/t/julia-info-precompiling-differentialequations-0c46a032-eb83-5123-abaf-570d42b7fbaa-error-loaderror-undefvarerror-undefmatrix-not-defined/94112 "2023-02-06T01:16:04Z")

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Hello, I have started to use Julia (very recently) At the beginning I was having a precompiled error. Then I have updated julia simply by the following commands: \]add UpdateJulia using UpdateJulia update\_julia() And …

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## [3 Layered Neural Network for a simple curve fit not working](https://discourse.julialang.org/t/3-layered-neural-network-for-a-simple-curve-fit-not-working/94078)

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**Author:** [@RSH](https://discourse.julialang.org/u/RSH)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 12:30am UTC](https://discourse.julialang.org/t/3-layered-neural-network-for-a-simple-curve-fit-not-working/94078 "2023-02-06T00:30:29Z")

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I am currently attempting to utilize a three-layered neural network to model the function cos(x). Despite extensive efforts to debug my code, I have been unable to identify and rectify the source of error. It is my belie…

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## [Zygote gradient error with \`reduce\` on GPU](https://discourse.julialang.org/t/zygote-gradient-error-with-reduce-on-gpu/94049)

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**Author:** [@ogoid](https://discourse.julialang.org/u/ogoid)\
**Replies:** 3\
**Last updated:** [February 6, 2023, 12:15am UTC](https://discourse.julialang.org/t/zygote-gradient-error-with-reduce-on-gpu/94049 "2023-02-06T00:15:03Z")

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Hello, I’m trying to use reduce (and mapreduce and its variants) in the loss function of a Flux neural network, but Zygote throws an error when it runs on the GPU (works fine on the CPU though). Are these functions unsu…

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## [How interpret constraint values for inequalities?](https://discourse.julialang.org/t/how-interpret-constraint-values-for-inequalities/93866)

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**Author:** [@hugh\_man](https://discourse.julialang.org/u/hugh_man)\
**Replies:** 3\
**Last updated:** [February 5, 2023, 11:59pm UTC](https://discourse.julialang.org/t/how-interpret-constraint-values-for-inequalities/93866 "2023-02-05T23:59:06Z")

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Hello, I’m trying to understand the values outputted when evaluating a constraint. In another thread I received this useful response on how to evaluate constraints. I’ll use a slightly modified example from there (pas…

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## [Mosek Solver Option](https://discourse.julialang.org/t/mosek-solver-option/94106)

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**Author:** [@A\_M](https://discourse.julialang.org/u/A_M)\
**Replies:** 3\
**Last updated:** [February 5, 2023, 11:57pm UTC](https://discourse.julialang.org/t/mosek-solver-option/94106 "2023-02-05T23:57:35Z")

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Solving a linear problem using Mosek, I set MSK\_DPAR\_INTPNT\_TOL\_PFEAS, which is Primal feasibility tolerance used by the interior-point optimizer for linear problems, to 1.0 by set\_optimizer\_attribute(model, "MSK\_DPAR\_I…

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## [Social hub for Julia startuppers?](https://discourse.julialang.org/t/social-hub-for-julia-startuppers/93123)

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**Author:** [@gvdr](https://discourse.julialang.org/u/gvdr)\
**Replies:** 5\
**Last updated:** [February 5, 2023, 11:18pm UTC](https://discourse.julialang.org/t/social-hub-for-julia-startuppers/93123 "2023-02-05T23:18:38Z")

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I’m floating here an idea I started to formulate. It may be silly, sorry about that. Or it may be something that other have done already (so, thank you about it and sorry if I’m duplicating your effort). Has anybody eve…

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## [Bayesian optimization](https://discourse.julialang.org/t/bayesian-optimization/94060)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 8\
**Last updated:** [February 5, 2023, 10:44pm UTC](https://discourse.julialang.org/t/bayesian-optimization/94060 "2023-02-05T22:44:45Z")

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Hello, I try to understand Bayesian optimization, which I want to use for the estimation of the power coefficient of a wind turbine which is a function of (at least) the wind speed and declines over the years. Can it b…

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## [What does @kwdef do?](https://discourse.julialang.org/t/what-does-kwdef-do/51973)

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**Author:** [@Ayush\_Rawat](https://discourse.julialang.org/u/Ayush_Rawat)\
**Replies:** 3\
**Last updated:** [February 5, 2023, 10:04pm UTC](https://discourse.julialang.org/t/what-does-kwdef-do/51973 "2023-02-05T22:04:29Z")

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I stumbled upon it in Plots.jl docs. But can’t find a description anywhere. I searched the official docs, and its pdf version. Looked at the Manual tab. On google and discourse alike, I’m able to find posts like this o…

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## [Manipulate sparse arrays](https://discourse.julialang.org/t/manipulate-sparse-arrays/94082)

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**Author:** [@Tri](https://discourse.julialang.org/u/Tri)\
**Replies:** 2\
**Last updated:** [February 5, 2023, 10:02pm UTC](https://discourse.julialang.org/t/manipulate-sparse-arrays/94082 "2023-02-05T22:02:44Z")

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I am using sparse array as variables in the following: using Ipopt,JuMP model = Model(Ipopt.Optimizer) n = 4 @variable(model, X\[i=1:n, j=1:i-1\] \>=0) @variable(model, y\[1:n\]\>=0) @variable(model, z\[1:n\]) @NLconstraint…

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## [Does delete! or Observable @view work with Axis3?](https://discourse.julialang.org/t/does-delete-or-observable-view-work-with-axis3/94061)

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**Author:** [@g2g](https://discourse.julialang.org/u/g2g)\
**Replies:** 2\
**Last updated:** [February 5, 2023, 8:59pm UTC](https://discourse.julialang.org/t/does-delete-or-observable-view-work-with-axis3/94061 "2023-02-05T20:59:10Z")

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As part of an essay (including a listing of the 3D PGA reference implementation ripga3d.jl in the appendix) proposing that Julia + Makie + projective geometric algebra (PGA) are an excellent combination for implementing …

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## [Solving DDE system using derivative at a previous time](https://discourse.julialang.org/t/solving-dde-system-using-derivative-at-a-previous-time/94015)

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**Author:** [@rogue26](https://discourse.julialang.org/u/rogue26)\
**Replies:** 7\
**Last updated:** [February 5, 2023, 8:03pm UTC](https://discourse.julialang.org/t/solving-dde-system-using-derivative-at-a-previous-time/94015 "2023-02-05T20:03:57Z")

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Hi. I’m trying to figure out to use DifferentialEquations.jl to solve a system of DDEs that depend not only on the values at previous times, but on the time derivatives of those values at previous times. For example, sup…

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## [Is it possible to avoid eval in this code?](https://discourse.julialang.org/t/is-it-possible-to-avoid-eval-in-this-code/93975)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 13\
**Last updated:** [February 5, 2023, 8:03pm UTC](https://discourse.julialang.org/t/is-it-possible-to-avoid-eval-in-this-code/93975 "2023-02-05T20:03:50Z")

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I would like to write a macro which subsets a collection of variables (with shared dimensions). My use case can be simplified to a dictionary of vectors where each vector has the same length, for example: ds = Dict(:a =\>…

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## [, and . in numbers inside CSV format](https://discourse.julialang.org/t/and-in-numbers-inside-csv-format/94087)

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**Author:** [@mpirke](https://discourse.julialang.org/u/mpirke)\
**Replies:** 7\
**Last updated:** [February 5, 2023, 5:30pm UTC](https://discourse.julialang.org/t/and-in-numbers-inside-csv-format/94087 "2023-02-05T17:30:48Z")

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Hey there! I have to following problem. I want to read in data ( .csv ) which has the following structure: data = """ col1;col2;col3;col4;col5 "05.02.2023";1000,01;2000,02;3000,03;12:00:00 "06.02.2023";4000,04;5000,05;…

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## [NeoVim + LanguageServer -- Packages not being sourced](https://discourse.julialang.org/t/neovim-languageserver-packages-not-being-sourced/93647)

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**Author:** [@Santiago\_Lopez](https://discourse.julialang.org/u/Santiago_Lopez)\
**Replies:** 11\
**Last updated:** [February 5, 2023, 4:45pm UTC](https://discourse.julialang.org/t/neovim-languageserver-packages-not-being-sourced/93647 "2023-02-05T16:45:41Z")

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I’m using NeoVim with LSP and cmp. My configuration works correctly; cmp correctly sources all the language servers I require (Python, Julia, R…) and shows no problem at all. However, when I work with Python for example,…

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## [New Julia Discourse Favicon!](https://discourse.julialang.org/t/new-julia-discourse-favicon/94093)

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**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 0\
**Last updated:** [February 5, 2023, 4:14pm UTC](https://discourse.julialang.org/t/new-julia-discourse-favicon/94093 "2023-02-05T16:14:49Z")

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Hey all, we just shipped a new discourse icon thanks to @cormullion! It might take some time to show up (or you can clear your cache to see it right away) but this should help you visually distinguish tabs on Discourse v…

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## [Error using @sync/@async within macro, help is highly appreciated](https://discourse.julialang.org/t/error-using-sync-async-within-macro-help-is-highly-appreciated/94080)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 2\
**Last updated:** [February 5, 2023, 3:05pm UTC](https://discourse.julialang.org/t/error-using-sync-async-within-macro-help-is-highly-appreciated/94080 "2023-02-05T15:05:09Z")

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Hi there, I would like to write a macro which just waits until a next time, if I run it on my own in a repl, it works, but if I put it into a macro, it fails with ERROR: syntax: invalid let syntax around task.jl:453 h…

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