# Latest

**URL:** https://discourse.julialang.org/latest.md?page=963

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

**Page:** 964

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## [How to export this type of vector like matlab .mat](https://discourse.julialang.org/t/how-to-export-this-type-of-vector-like-matlab-mat/85223)

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**Author:** [@Starpower\_Power](https://discourse.julialang.org/u/Starpower_Power)\
**Replies:** 0\
**Last updated:** [August 3, 2022, 11:48am UTC](https://discourse.julialang.org/t/how-to-export-this-type-of-vector-like-matlab-mat/85223 "2022-08-03T11:48:56Z")

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i have to save this variable res so i can call this variable without run the code please help on that. using Rotations using LinearAlgebra function trans(x) alpha=x\[1\]; a=x\[2\]; d=x\[3\]; t=x\[4\] T=\[ cos(t)…

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## [Why does a macro fail if passed constructed symbols as arguments?](https://discourse.julialang.org/t/why-does-a-macro-fail-if-passed-constructed-symbols-as-arguments/85221)

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**Author:** [@Soldalma](https://discourse.julialang.org/u/Soldalma)\
**Replies:** 0\
**Last updated:** [August 3, 2022, 11:26am UTC](https://discourse.julialang.org/t/why-does-a-macro-fail-if-passed-constructed-symbols-as-arguments/85221 "2022-08-03T11:26:56Z")

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This code works produces a nice chart: using DataFrames, StatsPlots df = DataFrame(A = rand(20), C = repeat(\[1,2,3, 4\], inner = 5)) plt\_dens1 = @df df density( :A, group = :C, title = "This works" ) If th…

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## [How to represent mixture state with cgrad in plots.jl](https://discourse.julialang.org/t/how-to-represent-mixture-state-with-cgrad-in-plots-jl/84706)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 16\
**Last updated:** [August 3, 2022, 11:21am UTC](https://discourse.julialang.org/t/how-to-represent-mixture-state-with-cgrad-in-plots-jl/84706 "2022-08-03T11:21:32Z")

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Hi all, I am working with a model that could be classified as a hidden semi-Markov model. The hidden state is not observable, but it could be estimated from the model and displayed graphically. I am interested in repre…

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## [Question about low pass filter in DSP.jl](https://discourse.julialang.org/t/question-about-low-pass-filter-in-dsp-jl/79214)

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**Author:** [@henry2004y](https://discourse.julialang.org/u/henry2004y)\
**Replies:** 5\
**Last updated:** [August 3, 2022, 10:00am UTC](https://discourse.julialang.org/t/question-about-low-pass-filter-in-dsp-jl/79214 "2022-08-03T10:00:16Z")

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Hi, I’m new to the domain of signal processing. Recently I have encountered some phase related issues with the low pass filter in DSP.jl. In MATLAB, fs = 1e3; t = 0:1/fs:1; % comment out random noise for testing x = \[…

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## [Linear Fit](https://discourse.julialang.org/t/linear-fit/84847)

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**Author:** [@Yangheng\_Jizhe](https://discourse.julialang.org/u/Yangheng_Jizhe)\
**Replies:** 8\
**Last updated:** [August 3, 2022, 9:12am UTC](https://discourse.julialang.org/t/linear-fit/84847 "2022-08-03T09:12:42Z")

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Hi! I’m a newbie to Julia and I’ve been trying to fit some scatter points ( coordinates in arrays ) to a line that goes through the origin. Anyone has any recommended functions and packages? I tried LinearLeastSquares p…

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## [Is it necessary to add GR.jl?](https://discourse.julialang.org/t/is-it-necessary-to-add-gr-jl/85217)

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**Author:** [@vitaminace33](https://discourse.julialang.org/u/vitaminace33)\
**Replies:** 3\
**Last updated:** [August 3, 2022, 8:48am UTC](https://discourse.julialang.org/t/is-it-necessary-to-add-gr-jl/85217 "2022-08-03T08:48:13Z")

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GR is the default backend for plotting and works out of the box. Hence, the question, is it necessary to add GR.jl via Pkg.add? Would this add any extra capabilities to plotting?

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## ["Run file in New Process" in VS Code runs forever](https://discourse.julialang.org/t/run-file-in-new-process-in-vs-code-runs-forever/85208)

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**Author:** [@Alehud](https://discourse.julialang.org/u/Alehud)\
**Replies:** 3\
**Last updated:** [August 3, 2022, 8:11am UTC](https://discourse.julialang.org/t/run-file-in-new-process-in-vs-code-runs-forever/85208 "2022-08-03T08:11:42Z")

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I have a file with a simple single-line code println("Hello") . When I press “Julia: Run File in New Process” in VS Code on Windows 10, it is trying to start the process forever. It shows the little palette with the red…

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## [Problem with precompiling HTTP and LiveServer](https://discourse.julialang.org/t/problem-with-precompiling-http-and-liveserver/85184)

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**Author:** [@paniash](https://discourse.julialang.org/u/paniash)\
**Replies:** 4\
**Last updated:** [August 3, 2022, 8:11am UTC](https://discourse.julialang.org/t/problem-with-precompiling-http-and-liveserver/85184 "2022-08-03T08:11:41Z")

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Hi everyone! I’m trying to install HTTP and LiveServer in my default environment but I seem to be getting the following error message: (@v1.7) pkg\> add HTTP Installing known registries into \`~/.julia\` Updating re…

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## [Can not choose alg for lyapunovspectrum DynamicalSystems.jl](https://discourse.julialang.org/t/can-not-choose-alg-for-lyapunovspectrum-dynamicalsystems-jl/85173)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 9\
**Last updated:** [August 3, 2022, 7:46am UTC](https://discourse.julialang.org/t/can-not-choose-alg-for-lyapunovspectrum-dynamicalsystems-jl/85173 "2022-08-03T07:46:32Z")

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I have system and parametres: function HR!(du, u, p, t) function sigma(x) return 1.0 / ( 1.0 + exp( -10.0 \* ( x - ( - 0.25 ) ) ) ) end a, b, c, d, s, xr, r, I, vs, k1, k2, el\_link = …

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## [Memory on array element assignment](https://discourse.julialang.org/t/memory-on-array-element-assignment/85069)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 10\
**Last updated:** [August 3, 2022, 6:53am UTC](https://discourse.julialang.org/t/memory-on-array-element-assignment/85069 "2022-08-03T06:53:40Z")

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I am writing some sort of histogramming function and am having trouble with bad performance due to dynamic allocations in each assignment. It boils down to the following simple problem: julia\> a=zeros(UInt16,1000000); …

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## [Vectors Addition only work with initial (0,0)?](https://discourse.julialang.org/t/vectors-addition-only-work-with-initial-0-0/85144)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 4\
**Last updated:** [August 3, 2022, 5:51am UTC](https://discourse.julialang.org/t/vectors-addition-only-work-with-initial-0-0/85144 "2022-08-03T05:51:33Z")

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Hi all, I have been learning from this site: https://docs.juliahub.com/CalculusWithJulia/AZHbv/0.0.5/differentiable\_vector\_calculus/vectors.html# then I change the initial point and see the second vector is not in the…

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## [Generating all string possibilities with wildcard characters? (code golf-based)](https://discourse.julialang.org/t/generating-all-string-possibilities-with-wildcard-characters-code-golf-based/85209)

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**Author:** [@mostol](https://discourse.julialang.org/u/mostol)\
**Replies:** 1\
**Last updated:** [August 3, 2022, 12:22am UTC](https://discourse.julialang.org/t/generating-all-string-possibilities-with-wildcard-characters-code-golf-based/85209 "2022-08-03T00:22:11Z")

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I ran into this code golf problem on StackExchange. The premise is that you take in a short string with some wildcard characters (\*) and return all of the possible variations of that string, replacing the wildcards with …

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## [Appending a matrix to a vector of matrices](https://discourse.julialang.org/t/appending-a-matrix-to-a-vector-of-matrices/85191)

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**Author:** [@Gus\_Hart](https://discourse.julialang.org/u/Gus_Hart)\
**Replies:** 10\
**Last updated:** [August 2, 2022, 11:30pm UTC](https://discourse.julialang.org/t/appending-a-matrix-to-a-vector-of-matrices/85191 "2022-08-02T23:30:43Z")

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I have a long list (vector) of matrices. They are size 3xn where n is typically 1 \< n \< 7. My long list typically varies between 100K and 1 million. My task is to reduce this list using a rather complicated and expensive…

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## [Programmatic installation of Julia packages?](https://discourse.julialang.org/t/programmatic-installation-of-julia-packages/85207)

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**Author:** [@wsphd](https://discourse.julialang.org/u/wsphd)\
**Replies:** 1\
**Last updated:** [August 2, 2022, 11:23pm UTC](https://discourse.julialang.org/t/programmatic-installation-of-julia-packages/85207 "2022-08-02T23:23:00Z")

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In R, I can use install.packages() to install packages programmatically, Similarly, in Python I can use mamba, conda, or pip. I know how to install Julia packages from the REPL (press “\]” to go into Package handler). H…

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## [How do I get readdlm to return a Matrix of strings?](https://discourse.julialang.org/t/how-do-i-get-readdlm-to-return-a-matrix-of-strings/85186)

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**Author:** [@eyeHawk](https://discourse.julialang.org/u/eyeHawk)\
**Replies:** 12\
**Last updated:** [August 2, 2022, 10:43pm UTC](https://discourse.julialang.org/t/how-do-i-get-readdlm-to-return-a-matrix-of-strings/85186 "2022-08-02T22:43:12Z")

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I am reading in a list of english words into my program. I then want to make sure the words are lowercase so I am processing the list with lowercase() one word at a time and pushing them into another list. It seems that …

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## [How to export this type of vector](https://discourse.julialang.org/t/how-to-export-this-type-of-vector/85139)

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**Author:** [@Starpower\_Power](https://discourse.julialang.org/u/Starpower_Power)\
**Replies:** 13\
**Last updated:** [August 2, 2022, 10:04pm UTC](https://discourse.julialang.org/t/how-to-export-this-type-of-vector/85139 "2022-08-02T22:04:37Z")

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how to export this type of vector locally, so i can call this vector as when i want, please tell me asap. thank YOU.

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## [Numerical inaccuracies when constructing correlation matrices](https://discourse.julialang.org/t/numerical-inaccuracies-when-constructing-correlation-matrices/85177)

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**Author:** [@daniel](https://discourse.julialang.org/u/daniel)\
**Replies:** 6\
**Last updated:** [August 2, 2022, 9:59pm UTC](https://discourse.julialang.org/t/numerical-inaccuracies-when-constructing-correlation-matrices/85177 "2022-08-02T21:59:56Z")

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I’m trying to sample correlation matrices using the vine method explained here: How to generate a large full-rank random correlation matrix with some strong correlations present? - Cross Validated (which is based on the…

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## [Online judge supports Julia?](https://discourse.julialang.org/t/online-judge-supports-julia/13625)

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**Author:** [@xiang0x48](https://discourse.julialang.org/u/xiang0x48)\
**Replies:** 5\
**Last updated:** [August 2, 2022, 9:41pm UTC](https://discourse.julialang.org/t/online-judge-supports-julia/13625 "2022-08-02T21:41:37Z")

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I’m new to Julia and just study by reading official documents, but I do want to have some toy problems as testing. I’m wondering if there is online judgement supports Julia? I’ve searched and found hackerrank was said t…

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## [Dirac Delta with DifferentialEquations.jl](https://discourse.julialang.org/t/dirac-delta-with-differentialequations-jl/84835)

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**Author:** [@cmdenis](https://discourse.julialang.org/u/cmdenis)\
**Replies:** 4\
**Last updated:** [August 2, 2022, 8:18pm UTC](https://discourse.julialang.org/t/dirac-delta-with-differentialequations-jl/84835 "2022-08-02T20:18:55Z")

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Hi, I want to integrate a differential equations system numerically, but some equations involve Dirac delta functions. Is there a built-in delta function to do this? Or should I be mimicking one with a continuous funct…

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## [Why isn't this type signature allowed?](https://discourse.julialang.org/t/why-isnt-this-type-signature-allowed/85170)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 18\
**Last updated:** [August 2, 2022, 7:30pm UTC](https://discourse.julialang.org/t/why-isnt-this-type-signature-allowed/85170 "2022-08-02T19:30:58Z")

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Given that functions f, g, and h all work, why isn’t function i allowed? Shouldn’t i work like an alias for g just like h does? x = 1 y = 0.1 function f(x::Number, y::Number) return "This is function f." end functi…

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## [How to output selective elements from Matrix?](https://discourse.julialang.org/t/how-to-output-selective-elements-from-matrix/85110)

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**Author:** [@Amro](https://discourse.julialang.org/u/Amro)\
**Replies:** 11\
**Last updated:** [August 2, 2022, 7:29pm UTC](https://discourse.julialang.org/t/how-to-output-selective-elements-from-matrix/85110 "2022-08-02T19:29:36Z")

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I have the below configuration. I am trying to output selective elements from matrix L.sl based on values of L.Seg. More specifically, I want to write syntax such as L.sl\[L.Seg\] to give me the same results as S. Any simp…

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## [Naive tcp chat server](https://discourse.julialang.org/t/naive-tcp-chat-server/85182)

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**Author:** [@KirillGerke](https://discourse.julialang.org/u/KirillGerke)\
**Replies:** 0\
**Last updated:** [August 2, 2022, 5:51pm UTC](https://discourse.julialang.org/t/naive-tcp-chat-server/85182 "2022-08-02T17:51:00Z")

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Dear All! For learning and practical purposes i tried to write a tcp server. It is supposed to accept multiple connections and provide capabilities of a chat server. I tried a number of things according to documentation…

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## [Precompile statements files vs Precompile excecution files](https://discourse.julialang.org/t/precompile-statements-files-vs-precompile-excecution-files/77741)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 2\
**Last updated:** [August 2, 2022, 4:57pm UTC](https://discourse.julialang.org/t/precompile-statements-files-vs-precompile-excecution-files/77741 "2022-08-02T16:57:35Z")

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On the VSCode page on sysimages, one can find the following example content of ./.vscode/JuliaSysimage.toml \[sysimage\] exclude=\[\] # Additional packages to be exlucded in the system image statements\_files=\[\] # Precomp…

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## [How can I change a single color in a Plots.jl palette?](https://discourse.julialang.org/t/how-can-i-change-a-single-color-in-a-plots-jl-palette/85172)

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**Author:** [@thompsonmj](https://discourse.julialang.org/u/thompsonmj)\
**Replies:** 4\
**Last updated:** [August 2, 2022, 4:04pm UTC](https://discourse.julialang.org/t/how-can-i-change-a-single-color-in-a-plots-jl-palette/85172 "2022-08-02T16:04:11Z")

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If I have a palette, is there some way to change the colors by index? c = palette(:tab10) c\[10\] = colorant"black" ERROR: MethodError: no method matching setindex!(::ColorPalette, ::RGB{N0f8}, ::Int64)

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## [Errors in Parsers.PosLen loading dataframe from large CSV file (80M rows)](https://discourse.julialang.org/t/errors-in-parsers-poslen-loading-dataframe-from-large-csv-file-80m-rows/73897)

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**Author:** [@joshuarobinson](https://discourse.julialang.org/u/joshuarobinson)\
**Replies:** 7\
**Last updated:** [August 2, 2022, 2:52pm UTC](https://discourse.julialang.org/t/errors-in-parsers-poslen-loading-dataframe-from-large-csv-file-80m-rows/73897 "2022-08-02T14:52:15Z")

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Brand new to Julia and am unable to create a DataFrame from a test file that I’ve been using successfully with Pandas (if not slowly). The input is a single 5GB file with 80M lines and is space delimited. There are a few…

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## [Primitive type with 2 bits](https://discourse.julialang.org/t/primitive-type-with-2-bits/85095)

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**Author:** [@user\_231578](https://discourse.julialang.org/u/user_231578)\
**Replies:** 4\
**Last updated:** [August 2, 2022, 2:49pm UTC](https://discourse.julialang.org/t/primitive-type-with-2-bits/85095 "2022-08-02T14:49:55Z")

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I have a very large matrix (with millions of rows) which obviously uses a lot of memory. Each of its entry it is either 0, 1 or 2. At the moment, the matrix has type Array{Int8,2} but 2 bits per entry would suffice, and …

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## [Custom broadcasting for static, immutable type](https://discourse.julialang.org/t/custom-broadcasting-for-static-immutable-type/69426)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [August 2, 2022, 2:35pm UTC](https://discourse.julialang.org/t/custom-broadcasting-for-static-immutable-type/69426 "2022-08-02T14:35:45Z")

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Consider the following type with two fields, using StaticArrays struct Foo{T,N} x::T y::SVector{N,T} end The objective is to make broadcasting work for matching dimension N and scalars, error for everything …

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## [In \`StatsBase.jl\`, is it possible for \`sample\` to not return vectors?](https://discourse.julialang.org/t/in-statsbase-jl-is-it-possible-for-sample-to-not-return-vectors/85164)

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**Author:** [@drelatgithub](https://discourse.julialang.org/u/drelatgithub)\
**Replies:** 2\
**Last updated:** [August 2, 2022, 2:34pm UTC](https://discourse.julialang.org/t/in-statsbase-jl-is-it-possible-for-sample-to-not-return-vectors/85164 "2022-08-02T14:34:28Z")

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In StatsBase.jl, using sample function with many samples returns a vector with all the sample results. I might be overlooking the documents, but I’m looking for a way to “consume” each sample result in-place without buil…

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## [Broadcasting an expression-evaluator function](https://discourse.julialang.org/t/broadcasting-an-expression-evaluator-function/85127)

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**Author:** [@RXGottlieb](https://discourse.julialang.org/u/RXGottlieb)\
**Replies:** 2\
**Last updated:** [August 2, 2022, 2:21pm UTC](https://discourse.julialang.org/t/broadcasting-an-expression-evaluator-function/85127 "2022-08-02T14:21:46Z")

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Hello, I have a symbolic expression that I’d like to evaluate a large number of times on a GPU. A few days ago I made a post about creating an evaluator function (see: the previous post), which led me to Symbolics.build…

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## [Can not compile plots.jl in Ubuntu Docker](https://discourse.julialang.org/t/can-not-compile-plots-jl-in-ubuntu-docker/85165)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 0\
**Last updated:** [August 2, 2022, 1:37pm UTC](https://discourse.julialang.org/t/can-not-compile-plots-jl-in-ubuntu-docker/85165 "2022-08-02T13:37:25Z")

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When I try to precompile plots I get ✗ Cairo\_jll ✗ Qt5Base\_jll ✗ HarfBuzz\_jll ✗ libass\_jll ✗ FFMPEG\_jll ✗ FFMPEG ✗ GR\_jll ✗ Plots 0 dependencies successfully precompiled in 19 seconds (131 already prec…

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