# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1102

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

**Page:** 1103

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## [Powermodels.jl SCS for a mixed-integer problem with SDP relaxation](https://discourse.julialang.org/t/powermodels-jl-scs-for-a-mixed-integer-problem-with-sdp-relaxation/77244)

<div class="topic-metadata">

**Author:** [@lostamcimber](https://discourse.julialang.org/u/lostamcimber)\
**Replies:** 4\
**Last updated:** [March 8, 2022, 12:44pm UTC](https://discourse.julialang.org/t/powermodels-jl-scs-for-a-mixed-integer-problem-with-sdp-relaxation/77244 "2022-03-08T12:44:23Z")

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Hi all, I am trying to solve a mixed integer problem of a network with switches (switches are my binary variables). I can solve my OPF problem with quadratic relaxations like ‘SOCWRPowerModel’, ‘QCRMPowerModel’, ‘QCLSPo…

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## [GPU computing on AMD consumer hardware?](https://discourse.julialang.org/t/gpu-computing-on-amd-consumer-hardware/53841)

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**Author:** [@tp2750](https://discourse.julialang.org/u/tp2750)\
**Replies:** 11\
**Last updated:** [March 8, 2022, 12:40pm UTC](https://discourse.julialang.org/t/gpu-computing-on-amd-consumer-hardware/53841 "2022-03-08T12:40:55Z")

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I’m putting together a new computer and would like to be able to experiment with GPU computing in Julia (on Ubuntu). I would greatly prefer an AMD GPU because of the in-kernel driver support on Linux. My understanding i…

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## [How to add grid lines on top of a heatmap in Makie?](https://discourse.julialang.org/t/how-to-add-grid-lines-on-top-of-a-heatmap-in-makie/77578)

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**Author:** [@ForceBru](https://discourse.julialang.org/u/ForceBru)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 12:30pm UTC](https://discourse.julialang.org/t/how-to-add-grid-lines-on-top-of-a-heatmap-in-makie/77578 "2022-03-08T12:30:52Z")

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I have some code which boils down to heatmap(matrix, colormap=Reverse(:grays)) and produces this plot: There’s a lot of white in the plot, and I’d like to emphasize that it’s not empty space, so I wanted to add grid …

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## [Setting up a Function Chain with Single Allocation](https://discourse.julialang.org/t/setting-up-a-function-chain-with-single-allocation/77541)

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**Author:** [@underwhelmed](https://discourse.julialang.org/u/underwhelmed)\
**Replies:** 5\
**Last updated:** [March 8, 2022, 10:25am UTC](https://discourse.julialang.org/t/setting-up-a-function-chain-with-single-allocation/77541 "2022-03-08T10:25:54Z")

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Hello all, I would like to compose a function chain that will be applied to some data. The functions involved vary conditionally on said data, which isn’t known until runtime. Is there a way to do this without storing e…

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## [Generic Structs in Dicts](https://discourse.julialang.org/t/generic-structs-in-dicts/77569)

<div class="topic-metadata">

**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 2\
**Last updated:** [March 8, 2022, 10:15am UTC](https://discourse.julialang.org/t/generic-structs-in-dicts/77569 "2022-03-08T10:15:11Z")

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Hi all :slight\_smile: Does anyone know why the following doesn’t work? julia\> struct A{T} a::T end julia\> Dict{\<:A,Int} Dict{\<:A, Int64} julia\> Dict{\<:A,Int}() ERROR: MethodError: no method matching (Dict{\<:A, Int64}…

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## [Solving KKT linear system (which solver for LDLᵀ factorization?)](https://discourse.julialang.org/t/solving-kkt-linear-system-which-solver-for-ldl-factorization/77544)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 3\
**Last updated:** [March 8, 2022, 8:47am UTC](https://discourse.julialang.org/t/solving-kkt-linear-system-which-solver-for-ldl-factorization/77544 "2022-03-08T08:47:48Z")

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I would like to solve a system of linear equations given in a vector form as \\begin{bmatrix} Q & A^\\top \\\\ A & 0\\end{bmatrix}\\begin{bmatrix}x\\\\ \\lambda\\end{bmatrix} = \\begin{bmatrix} c \\\\ -b \\end{bmatrix} The matrix Q…

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## [How to standardize arrays in Julia?](https://discourse.julialang.org/t/how-to-standardize-arrays-in-julia/54046)

<div class="topic-metadata">

**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 7\
**Last updated:** [March 8, 2022, 7:46am UTC](https://discourse.julialang.org/t/how-to-standardize-arrays-in-julia/54046 "2022-03-08T07:46:16Z")

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I have two arrays (m and n) and each has one column with 100 elements. the first array is sampled from a normal distribution with mean 0 and standard deviation 1, the second one is sampled from a normal distribution with…

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## [Is it there a way to find where the deadlock is while using jupyter?](https://discourse.julialang.org/t/is-it-there-a-way-to-find-where-the-deadlock-is-while-using-jupyter/77563)

<div class="topic-metadata">

**Author:** [@Brian1](https://discourse.julialang.org/u/Brian1)\
**Replies:** 0\
**Last updated:** [March 8, 2022, 3:59am UTC](https://discourse.julialang.org/t/is-it-there-a-way-to-find-where-the-deadlock-is-while-using-jupyter/77563 "2022-03-08T03:59:45Z")

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I am using multithreads in jupyter, but often some deadlocks were triggered. When this happened, the jupyter kernel is just keep running and no error message printed, so I have to restart the kernel. After that, I have …

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## [How does Julia merge several exprs to one expr?](https://discourse.julialang.org/t/how-does-julia-merge-several-exprs-to-one-expr/77498)

<div class="topic-metadata">

**Author:** [@Brian1](https://discourse.julialang.org/u/Brian1)\
**Replies:** 5\
**Last updated:** [March 8, 2022, 3:48am UTC](https://discourse.julialang.org/t/how-does-julia-merge-several-exprs-to-one-expr/77498 "2022-03-08T03:48:04Z")

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There is the problem:

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## [Neos Server](https://discourse.julialang.org/t/neos-server/77549)

<div class="topic-metadata">

**Author:** [@Francisco\_Javier\_Mar](https://discourse.julialang.org/u/Francisco_Javier_Mar)\
**Replies:** 1\
**Last updated:** [March 8, 2022, 2:19am UTC](https://discourse.julialang.org/t/neos-server/77549 "2022-03-08T02:19:13Z")

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I got this error while trying to install NEOSServer. What can I do ? ERROR: Unsatisfiable requirements detected for package HTTP \[cd3eb016\]: HTTP \[cd3eb016\] log: ├─possible versions are: \[0.6.10-0.6.14, 0.7.0-0.7.1, 0…

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## [Ismatch not defined error](https://discourse.julialang.org/t/ismatch-not-defined-error/67096)

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**Author:** [@orsos](https://discourse.julialang.org/u/orsos)\
**Replies:** 5\
**Last updated:** [March 8, 2022, 12:24am UTC](https://discourse.julialang.org/t/ismatch-not-defined-error/67096 "2022-03-08T00:24:00Z")

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following function directory\_images = filter(x → ismatch(r"/.(jpg|png|gif){1}$"i, x), directory\_files); returns ismatch not defined error. do i need a specific package for ismatch

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## [BenchmarkTools @benchmark beautiful histogram reuse](https://discourse.julialang.org/t/benchmarktools-benchmark-beautiful-histogram-reuse/75053)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 12\
**Last updated:** [March 7, 2022, 8:59pm UTC](https://discourse.julialang.org/t/benchmarktools-benchmark-beautiful-histogram-reuse/75053 "2022-03-07T20:59:36Z")

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Dear Julianners, I saw the beautiful histogram unicode plots of BenchmarkTools of @benchmark BenchmarkTools.Trial: 10000 samples with 968 evaulations took a median time of 90.902 ns (0.00% GC) Time (mean ± σ): 94.…

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## [ERROR: Unable to automatically install 'Libtiff' on Windows 10](https://discourse.julialang.org/t/error-unable-to-automatically-install-libtiff-on-windows-10/77509)

<div class="topic-metadata">

**Author:** [@fredrikpaues](https://discourse.julialang.org/u/fredrikpaues)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 8:26pm UTC](https://discourse.julialang.org/t/error-unable-to-automatically-install-libtiff-on-windows-10/77509 "2022-03-07T20:26:18Z")

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I’m on a Windows 10 machine running Julia 1.6 and was just now hoping to start profile some code, but alas was hit by this error message when trying to install the Profile package. Help would be much appreciated! (@v1.6…

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## [Automotive/EV projects/packages?](https://discourse.julialang.org/t/automotive-ev-projects-packages/77533)

<div class="topic-metadata">

**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 2\
**Last updated:** [March 7, 2022, 7:46pm UTC](https://discourse.julialang.org/t/automotive-ev-projects-packages/77533 "2022-03-07T19:46:56Z")

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So I’m looking to dabble a bit with data from an OBD2 scanner, mostly to explore aspects of my EV’s energy consumption, and/or something about how the charging infrastructure is evolving, if I can find an appropriate API…

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## [CUDA.jl initialization test failing](https://discourse.julialang.org/t/cuda-jl-initialization-test-failing/77526)

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**Author:** [@RonRahaman](https://discourse.julialang.org/u/RonRahaman)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 5:56pm UTC](https://discourse.julialang.org/t/cuda-jl-initialization-test-failing/77526 "2022-03-07T17:56:06Z")

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Hi all, I’m running tests for CUDA.jl (\]test CUDA) and I have one test failing. Should I be concerned, or can I safely ignore it? Error in testset initialization: Test Failed at /usr/local/pace-apps/manual/packages/jul…

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## [OneNote/Microsoft Graph API](https://discourse.julialang.org/t/onenote-microsoft-graph-api/76264)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 0\
**Last updated:** [February 11, 2022, 6:05pm UTC](https://discourse.julialang.org/t/onenote-microsoft-graph-api/76264 "2022-02-11T18:05:59Z")

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Has anyone experimented at all with the OneNote REST API?

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## [Maximum Likelihood Estimation](https://discourse.julialang.org/t/maximum-likelihood-estimation/77527)

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**Author:** [@maria96](https://discourse.julialang.org/u/maria96)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 4:58pm UTC](https://discourse.julialang.org/t/maximum-likelihood-estimation/77527 "2022-03-07T16:58:13Z")

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Hi all, I’ve been into Julia for a week now. I managed to transfer all my code from R to Julia and the results I obtain in Julia are what I expect. However, when I try to obtain the maximum likelihood estimates from my…

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## [Code highlight in VScode](https://discourse.julialang.org/t/code-highlight-in-vscode/77525)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 4:40pm UTC](https://discourse.julialang.org/t/code-highlight-in-vscode/77525 "2022-03-07T16:40:02Z")

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I’m not sure if that changed after some upgrade, but the code highlight in VSCode is not looking nice now. Here is a comparison with what appears on the github page: VSCode: Github: Is that expected? Should I tune…

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## [Error using system CUDA in CUDA.jl](https://discourse.julialang.org/t/error-using-system-cuda-in-cuda-jl/77423)

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**Author:** [@RonRahaman](https://discourse.julialang.org/u/RonRahaman)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 4:19pm UTC](https://discourse.julialang.org/t/error-using-system-cuda-in-cuda-jl/77423 "2022-03-07T16:19:17Z")

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Hi all, I’m trying to install CUDA.jl using my system’s CUDA toolkit. The installation completes, but I get errors when I try to test it by running CUDA.version(). I set JULIA\_CUDA\_USE\_BINARYBUILDER=false and ensured t…

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## [Helpful design article from CACM: "Human-centered approach to static-analysis-driven developer tools"](https://discourse.julialang.org/t/helpful-design-article-from-cacm-human-centered-approach-to-static-analysis-driven-developer-tools/77522)

<div class="topic-metadata">

**Author:** [@caleb-allen](https://discourse.julialang.org/u/caleb-allen)\
**Replies:** 0\
**Last updated:** [March 7, 2022, 4:15pm UTC](https://discourse.julialang.org/t/helpful-design-article-from-cacm-human-centered-approach-to-static-analysis-driven-developer-tools/77522 "2022-03-07T16:15:32Z")

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Hello! I thought I’d share this article from the latest issue of the Communications of the ACM. It seems especially relevant considering the work being done in the julia VS-Code plugin, as well as the static analysis p…

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## [Start using Molly.jl: place\_atoms not defined in module Molly?](https://discourse.julialang.org/t/start-using-molly-jl-place-atoms-not-defined-in-module-molly/77521)

<div class="topic-metadata">

**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 3\
**Last updated:** [March 7, 2022, 4:14pm UTC](https://discourse.julialang.org/t/start-using-molly-jl-place-atoms-not-defined-in-module-molly/77521 "2022-03-07T16:14:53Z")

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I started looking into Molly.jl and attempting to run one its examples. I get the error described below. Insight would be nice to receive. Thx! julia\> using Molly julia\> n\_atoms = 100 100 julia\> atom\_mass = 10.0u"u" …

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## [Concrete Operators in DiffEqOperators.jl for time-indepedent problems](https://discourse.julialang.org/t/concrete-operators-in-diffeqoperators-jl-for-time-indepedent-problems/77415)

<div class="topic-metadata">

**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 9\
**Last updated:** [March 7, 2022, 3:31pm UTC](https://discourse.julialang.org/t/concrete-operators-in-diffeqoperators-jl-for-time-indepedent-problems/77415 "2022-03-07T15:31:59Z")

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We are looking into the use of DiffEqOperators for time-independent problems. We are considering the Poisson equation on the unit interval and unit square. First a 1D implementation was made to figure out how to use it. …

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## [Outdated / bogus CUDA.jl documentation at https://juliagpu.gitlab.io/CUDA.jl?](https://discourse.julialang.org/t/outdated-bogus-cuda-jl-documentation-at-https-juliagpu-gitlab-io-cuda-jl/77515)

<div class="topic-metadata">

**Author:** [@complyue](https://discourse.julialang.org/u/complyue)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 3:13pm UTC](https://discourse.julialang.org/t/outdated-bogus-cuda-jl-documentation-at-https-juliagpu-gitlab-io-cuda-jl/77515 "2022-03-07T15:13:49Z")

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By CUDA.jl - Google Search , the first hit is the github repo, which is good, but the second hit is https://juliagpu.gitlab.io/CUDA.jl , which seems outdated, compared to https://cuda.juliagpu.org . But the later doesn’t…

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## [Stencil operations and Symbolics.jl](https://discourse.julialang.org/t/stencil-operations-and-symbolics-jl/75685)

<div class="topic-metadata">

**Author:** [@vlc](https://discourse.julialang.org/u/vlc)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 3:11pm UTC](https://discourse.julialang.org/t/stencil-operations-and-symbolics-jl/75685 "2022-03-07T15:11:36Z")

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Hi there, I’m writing a little package that solves classical PDEs on Cartesian grids, and am seeking advice on how to leverage Symbolics.jl to speed up operations such as matrix-vector products. As a MWE, I’ll focus on…

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## [Manging Local Package & Workflow](https://discourse.julialang.org/t/manging-local-package-workflow/77488)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 4\
**Last updated:** [March 7, 2022, 2:43pm UTC](https://discourse.julialang.org/t/manging-local-package-workflow/77488 "2022-03-07T14:43:39Z")

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Hello, I have a package I am developing locally. I created the package using \] generate and have added it to a local registry so that I may share it easily with collaborators. Both the package and the local registry hav…

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## [Question about generics and \`Base.@kwdef\`](https://discourse.julialang.org/t/question-about-generics-and-base-kwdef/77514)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 2:41pm UTC](https://discourse.julialang.org/t/question-about-generics-and-base-kwdef/77514 "2022-03-07T14:41:38Z")

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Hi all :slight\_smile: What did I do wrong? The following doesn’t work. Base.@kwdef struct A{T} a::T = T() function A(a::T) where T new{T}(a) end end struct B end A{B}() ERROR: LoadError: MethodEr…

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## [How to calculate a constant the first time a function is called?](https://discourse.julialang.org/t/how-to-calculate-a-constant-the-first-time-a-function-is-called/77506)

<div class="topic-metadata">

**Author:** [@andrey2185](https://discourse.julialang.org/u/andrey2185)\
**Replies:** 5\
**Last updated:** [March 7, 2022, 2:27pm UTC](https://discourse.julialang.org/t/how-to-calculate-a-constant-the-first-time-a-function-is-called/77506 "2022-03-07T14:27:05Z")

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Hello, how to calculate a constant the first time a function is called? not when compiling not every call foo() = (sleep(1); 1) # foo calculate a constant bar(x) = foo() + x # ???? # first call: @time bar(2) # -\> …

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## [Allocations when assigning Static Array in mutable struct](https://discourse.julialang.org/t/allocations-when-assigning-static-array-in-mutable-struct/77508)

<div class="topic-metadata">

**Author:** [@ncxst](https://discourse.julialang.org/u/ncxst)\
**Replies:** 1\
**Last updated:** [March 7, 2022, 2:01pm UTC](https://discourse.julialang.org/t/allocations-when-assigning-static-array-in-mutable-struct/77508 "2022-03-07T14:01:14Z")

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Hi, I encountered some allocations in my code that I can pin down to the following foobar example. When assigning a static array to a variable in a struct i get allocations, which I don’t get when the static array gets…

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## [What are uses/significance of "@" and "!" in Julia](https://discourse.julialang.org/t/what-are-uses-significance-of-and-in-julia/77507)

<div class="topic-metadata">

**Author:** [@iAnkiit](https://discourse.julialang.org/u/iAnkiit)\
**Replies:** 2\
**Last updated:** [March 7, 2022, 1:57pm UTC](https://discourse.julialang.org/t/what-are-uses-significance-of-and-in-julia/77507 "2022-03-07T13:57:50Z")

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I am new to Julia and working on a project written in Julia. What are uses/significance of “@” and “!” in Julia?

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## [Force specialization on kwargs](https://discourse.julialang.org/t/force-specialization-on-kwargs/34789)

<div class="topic-metadata">

**Author:** [@dilumaluthge](https://discourse.julialang.org/u/dilumaluthge)\
**Replies:** 15\
**Last updated:** [March 7, 2022, 1:46pm UTC](https://discourse.julialang.org/t/force-specialization-on-kwargs/34789 "2022-03-07T13:46:53Z")

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If I have a function like this: f\_vararg(varargs::Int...) = tuple(varargs...) I can force specialization on varargs with either of the following: g\_vararg(varargs::Vararg{Int, N}) where {N} = tuple(varargs...) h\_vara…

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