# Latest

**URL:** https://discourse.julialang.org/latest.md?page=605

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

**Page:** 606

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## [Declaration of variables](https://discourse.julialang.org/t/declaration-of-variables/103508)

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**Author:** [@Alois](https://discourse.julialang.org/u/Alois)\
**Replies:** 2\
**Last updated:** [September 4, 2023, 1:42pm UTC](https://discourse.julialang.org/t/declaration-of-variables/103508 "2023-09-04T13:42:00Z")

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How is a variable declared as a simple Float64, say, without initializing it? Something like A= Array{Float64, 0}(undef), which works for vectors.

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## [Using \`eval\` inside \`quote\`](https://discourse.julialang.org/t/using-eval-inside-quote/103505)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 2\
**Last updated:** [September 4, 2023, 1:33pm UTC](https://discourse.julialang.org/t/using-eval-inside-quote/103505 "2023-09-04T13:33:47Z")

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I’ve recently added a new feature to CounterfactualExplanations.jl that adds support for multi-processing through MPI. On the user-end, this is handled through a simple macro: ces = @with\_parallelizer parallelizer begin…

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## [AWS S3 upload a file](https://discourse.julialang.org/t/aws-s3-upload-a-file/103503)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 0\
**Last updated:** [September 4, 2023, 10:59am UTC](https://discourse.julialang.org/t/aws-s3-upload-a-file/103503 "2023-09-04T10:59:54Z")

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Is there a way to easily upload a file to S3 or does one always have to create an IOBuffer read the file and upload the content that way. If that is the case is there any general way of doing this which works on text dat…

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## [Python in Excel](https://discourse.julialang.org/t/python-in-excel/103279)

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**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 6\
**Last updated:** [September 4, 2023, 10:51am UTC](https://discourse.julialang.org/t/python-in-excel/103279 "2023-09-04T10:51:46Z")

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The tool which is the most used across my company is without a doubt Excel, 2nd is Python. Now Microsoft will combine them. I find the following quite huge for Python and it is another way to affirm its dominance over a…

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## [Does return type declaration make function type stable?](https://discourse.julialang.org/t/does-return-type-declaration-make-function-type-stable/103473)

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**Author:** [@homocomputeris](https://discourse.julialang.org/u/homocomputeris)\
**Replies:** 7\
**Last updated:** [September 4, 2023, 10:50am UTC](https://discourse.julialang.org/t/does-return-type-declaration-make-function-type-stable/103473 "2023-09-04T10:50:54Z")

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Docs read: Return type declarations are rarely used in Julia: in general, you should instead write “type-stable” functions in which Julia’s compiler can automatically infer the return type. For more information, see th…

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## [How to test all sub-packages from the root package?](https://discourse.julialang.org/t/how-to-test-all-sub-packages-from-the-root-package/103498)

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**Author:** [@thinnerichs](https://discourse.julialang.org/u/thinnerichs)\
**Replies:** 0\
**Last updated:** [September 4, 2023, 9:16am UTC](https://discourse.julialang.org/t/how-to-test-all-sub-packages-from-the-root-package/103498 "2023-09-04T09:16:55Z")

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Hello, We are currently developing a package with multiple sub-packages, all registered. I would like to jointly test all sub-packages when running the tests of the main package. However, I cannot find a neat way of do…

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## [PlotlyJS question: How to change color of stacked bar](https://discourse.julialang.org/t/plotlyjs-question-how-to-change-color-of-stacked-bar/103495)

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**Author:** [@nnguyengiatan](https://discourse.julialang.org/u/nnguyengiatan)\
**Replies:** 2\
**Last updated:** [September 4, 2023, 8:08am UTC](https://discourse.julialang.org/t/plotlyjs-question-how-to-change-color-of-stacked-bar/103495 "2023-09-04T08:08:05Z")

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Hi all, I am using PlotlyJS.jl and trying to change color of stacked bar chart. p\_turnover\_s = plot( turnover\_size\_df, x=:year, y=:mean\_turnover, color=:size, text=:mean\_t…

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## [Tools and packages to automate type stability checks?](https://discourse.julialang.org/t/tools-and-packages-to-automate-type-stability-checks/103480)

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**Author:** [@homocomputeris](https://discourse.julialang.org/u/homocomputeris)\
**Replies:** 2\
**Last updated:** [September 3, 2023, 10:05pm UTC](https://discourse.julialang.org/t/tools-and-packages-to-automate-type-stability-checks/103480 "2023-09-03T22:05:56Z")

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If I understand correctly, return type annotations cannot meaningfully help with type stability. There is also @code\_warntype, @inferred, Cthulhu.jl and TypeStability.jl, but they all require pointwise manual macrosing …

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## [\[ANN\] GradValley.jl: A new package for Deep Learning with Julia](https://discourse.julialang.org/t/ann-gradvalley-jl-a-new-package-for-deep-learning-with-julia/103404)

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**Author:** [@Jonas208](https://discourse.julialang.org/u/Jonas208)\
**Replies:** 3\
**Last updated:** [September 3, 2023, 7:03pm UTC](https://discourse.julialang.org/t/ann-gradvalley-jl-a-new-package-for-deep-learning-with-julia/103404 "2023-09-03T19:03:51Z")

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I am really happy to announce my first Julia package today! GradValley.jl GradValley is a new lightweight package for Deep Learning written in 100% Julia. Currently, GradValley focuses on computer vision tasks. It runs…

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## [What callbacks/hooks exist in Base/stdlibs](https://discourse.julialang.org/t/what-callbacks-hooks-exist-in-base-stdlibs/103476)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 4\
**Last updated:** [September 3, 2023, 5:35pm UTC](https://discourse.julialang.org/t/what-callbacks-hooks-exist-in-base-stdlibs/103476 "2023-09-03T17:35:42Z")

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What hook exist in Base/Core/stdlibs? By hooks I mean places you can register an arbitrary function to run whenever something occurs. Ones I am aware of out of hand: finalizer(f, x) runs when object x has no program-…

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## [How do I get the current variable value within a macro?](https://discourse.julialang.org/t/how-do-i-get-the-current-variable-value-within-a-macro/103487)

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**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 1\
**Last updated:** [September 3, 2023, 4:55pm UTC](https://discourse.julialang.org/t/how-do-i-get-the-current-variable-value-within-a-macro/103487 "2023-09-03T16:55:09Z")

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macro getvar(x) println(x) return nothing end x = 1 @getvar x getvar sees x as a symbol and prints out “x” as expected. Now, let’s assume I need the x value for some further logic within the macro (not within…

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## [Stream large file via HTTP](https://discourse.julialang.org/t/stream-large-file-via-http/103486)

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**Author:** [@sschmidhuber](https://discourse.julialang.org/u/sschmidhuber)\
**Replies:** 0\
**Last updated:** [September 3, 2023, 4:45pm UTC](https://discourse.julialang.org/t/stream-large-file-via-http/103486 "2023-09-03T16:45:57Z")

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Hello all, my goal is to stream a large file via a HTTP GET request to a client. The file is potentially larger than my server’s memory. Related to that, I found the following on Stack Overflow: stream - Send a large fi…

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## [Symbolics.jl expressions that don't reduce to single type](https://discourse.julialang.org/t/symbolics-jl-expressions-that-dont-reduce-to-single-type/102551)

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**Author:** [@Eemilp](https://discourse.julialang.org/u/Eemilp)\
**Replies:** 5\
**Last updated:** [September 3, 2023, 4:27pm UTC](https://discourse.julialang.org/t/symbolics-jl-expressions-that-dont-reduce-to-single-type/102551 "2023-09-03T16:27:33Z")

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Hi, I’m trying to use Symbolics.jl to simplify some expressions in the domain of quantum mechanics. The problem I’m facing is that I would like to simplify a partial expression that does not exactly reduce to a single t…

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## [Extreme memory usage in nested loop](https://discourse.julialang.org/t/extreme-memory-usage-in-nested-loop/103471)

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**Author:** [@daviyan5](https://discourse.julialang.org/u/daviyan5)\
**Replies:** 8\
**Last updated:** [September 3, 2023, 1:05pm UTC](https://discourse.julialang.org/t/extreme-memory-usage-in-nested-loop/103471 "2023-09-03T13:05:41Z")

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I need to conduct extensive memory and performance testing on a memory-intensive function that creates mutable structs, temporary arrays, and more, even though most of the variables are type-defined. Running a single ins…

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## [The expression solution](https://discourse.julialang.org/t/the-expression-solution/103435)

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**Author:** [@ShalokShalom](https://discourse.julialang.org/u/ShalokShalom)\
**Replies:** 31\
**Last updated:** [September 3, 2023, 11:25am UTC](https://discourse.julialang.org/t/the-expression-solution/103435 "2023-09-03T11:25:26Z")

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Hi We all know, how good Julia solves the age-old ‘expression problem’ and I have a couple of questions to anybody, who uses both Julia, and some language like Haskell, F# or OCaml. As you know, as a user of these lang…

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## [@Maintainer of Julia Graphics](https://discourse.julialang.org/t/maintainer-of-julia-graphics/103246)

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**Author:** [@ShalokShalom](https://discourse.julialang.org/u/ShalokShalom)\
**Replies:** 16\
**Last updated:** [September 3, 2023, 10:55am UTC](https://discourse.julialang.org/t/maintainer-of-julia-graphics/103246 "2023-09-03T10:55:34Z")

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Can anybody from the Julia Graphics team transition the QML binding, please: Do we know, who has admin rights, and can we ping them? Thanks

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## [Eager finalization insertion location question](https://discourse.julialang.org/t/eager-finalization-insertion-location-question/103477)

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**Author:** [@Zentrik](https://discourse.julialang.org/u/Zentrik)\
**Replies:** 1\
**Last updated:** [September 3, 2023, 6:56am UTC](https://discourse.julialang.org/t/eager-finalization-insertion-location-question/103477 "2023-09-03T06:56:54Z")

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If I modify the example given here https://github.com/JuliaLang/julia/pull/46651#issuecomment-1253471390 to const FINALIZATION\_COUNT = Ref(0) init\_finalization\_count!() = FINALIZATION\_COUNT\[\] = 0 get\_finalization\_count(…

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## [How Preconditioners work for multiple eigenpairs](https://discourse.julialang.org/t/how-preconditioners-work-for-multiple-eigenpairs/103456)

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**Author:** [@Neo](https://discourse.julialang.org/u/Neo)\
**Replies:** 4\
**Last updated:** [September 3, 2023, 6:16am UTC](https://discourse.julialang.org/t/how-preconditioners-work-for-multiple-eigenpairs/103456 "2023-09-03T06:16:25Z")

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I am using Preconditioners.jl to precondition the eigensolver lobpcg in IterativeSolvers.jl. But the preconditioners didn’t worked for more than one vectors. Any ideas? This works when I need only one eigenpair. using …

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## [Plot Pane Issue](https://discourse.julialang.org/t/plot-pane-issue/103271)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 6\
**Last updated:** [September 3, 2023, 1:58am UTC](https://discourse.julialang.org/t/plot-pane-issue/103271 "2023-09-03T01:58:32Z")

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I’m not sure what I’ve done, but in VSCode my plots no longer show up in the plot pane when I do shift+enter. I am using VSCode Version 1.81.1 and Julia extension v1.49.2. For example until yesterday I could do the foll…

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## [Gram Schmidit python to julia](https://discourse.julialang.org/t/gram-schmidit-python-to-julia/103472)

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**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 10\
**Last updated:** [September 3, 2023, 1:46am UTC](https://discourse.julialang.org/t/gram-schmidit-python-to-julia/103472 "2023-09-03T01:46:58Z")

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Hello, good evening, I’m having troubles to port an algorithm(Gram Schmidit for qr decompoosition) from python to julia. My results are going to infinity in Orthogonal Q matrix. May someone help? # create the matrix …

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## [Error with ODE Tableaus by DiffEqDevTools](https://discourse.julialang.org/t/error-with-ode-tableaus-by-diffeqdevtools/103448)

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**Author:** [@simon79](https://discourse.julialang.org/u/simon79)\
**Replies:** 5\
**Last updated:** [September 2, 2023, 10:46pm UTC](https://discourse.julialang.org/t/error-with-ode-tableaus-by-diffeqdevtools/103448 "2023-09-02T22:46:16Z")

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I am having errors with the tableau methods for explicitRK using DiffEqDevTools listed in tableau-methods-list The code using DiffEqBase using DiffEqDevTools using OrdinaryDiffEq using ODEInterfaceDiffEq using SciMLB…

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## [Custom nonlinear curve fitting package?](https://discourse.julialang.org/t/custom-nonlinear-curve-fitting-package/103468)

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**Author:** [@PeX](https://discourse.julialang.org/u/PeX)\
**Replies:** 1\
**Last updated:** [September 2, 2023, 10:31pm UTC](https://discourse.julialang.org/t/custom-nonlinear-curve-fitting-package/103468 "2023-09-02T22:31:34Z")

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Hi all! I have a dataset that I want to fit a function to in the form of: y = a x^4 + b x^3 + c x^2 + dx + e + f sin(gx + h) I was trying to use LsqFit.jl , but the results are not great (unless I guess the parameters…

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## [Parametric function return type](https://discourse.julialang.org/t/parametric-function-return-type/103460)

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**Author:** [@raythurnevoid](https://discourse.julialang.org/u/raythurnevoid)\
**Replies:** 8\
**Last updated:** [September 2, 2023, 9:34pm UTC](https://discourse.julialang.org/t/parametric-function-return-type/103460 "2023-09-02T21:34:16Z")

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I wanted to create a function that takes in input a callback and can return its result while being able to tell Julia what’s going to be the return type (since the Function type is not parametric). This is the skeleton …

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## [Understanding Types Union{}](https://discourse.julialang.org/t/understanding-types-union/103466)

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**Author:** [@Denis\_Ivanov](https://discourse.julialang.org/u/Denis_Ivanov)\
**Replies:** 3\
**Last updated:** [September 2, 2023, 9:24pm UTC](https://discourse.julialang.org/t/understanding-types-union/103466 "2023-09-02T21:24:54Z")

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I read the manual about types carefully, but I can’t figure out how to do this. Let’s two types of data are possible: Vector{Int8} and Vector{Vector{Int8}} eg \[1, 0, 1\] and \[\[1, 1\], \[0\]\] Following the recommendations,…

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## [Ceiling division](https://discourse.julialang.org/t/ceiling-division/103467)

<div class="topic-metadata">

**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 1\
**Last updated:** [September 2, 2023, 7:57pm UTC](https://discourse.julialang.org/t/ceiling-division/103467 "2023-09-02T19:57:19Z")

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x ÷ k is faster than floor(Int, x/k). Is there an ceiling division function that rounds up instead of down, equivalent to but faster than ceil(Int, x/k)? julia\> f(x) = floor(Int, x/4) f (generic function with 1 method) …

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## [Issue of volume render with large 3D data](https://discourse.julialang.org/t/issue-of-volume-render-with-large-3d-data/103395)

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**Author:** [@dora\_ho](https://discourse.julialang.org/u/dora_ho)\
**Replies:** 3\
**Last updated:** [September 2, 2023, 6:26pm UTC](https://discourse.julialang.org/t/issue-of-volume-render-with-large-3d-data/103395 "2023-09-02T18:26:53Z")

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Hi, I was trying to volume render a very large 3D data withGLMakie. However, I found this exists a limit for the volume render. This is my plotting scripts GLMakie.volume!(x, y, z, 3DArray, algorithm=:mip , absorpt…

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## [GLMakie: Run a function when slider is released](https://discourse.julialang.org/t/glmakie-run-a-function-when-slider-is-released/103295)

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**Author:** [@f.ij](https://discourse.julialang.org/u/f.ij)\
**Replies:** 3\
**Last updated:** [September 2, 2023, 2:46pm UTC](https://discourse.julialang.org/t/glmakie-run-a-function-when-slider-is-released/103295 "2023-09-02T14:46:06Z")

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Quite a simple question: Is it possible to run a function specifically when a slider is released? A way to check whether the slider is currently being dragged would suffice. I couldn’t find a way to do this.

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## [\[ANN\] SFTPClient.jl Package for Working with SFTP Files](https://discourse.julialang.org/t/ann-sftpclient-jl-package-for-working-with-sftp-files/103462)

<div class="topic-metadata">

**Author:** [@stene](https://discourse.julialang.org/u/stene)\
**Replies:** 0\
**Last updated:** [September 2, 2023, 7:54am UTC](https://discourse.julialang.org/t/ann-sftpclient-jl-package-for-working-with-sftp-files/103462 "2023-09-02T07:54:56Z")

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SFTPClient simplifies working with SFTP Files in Julia. Built on top of Downloads.jl, and provides readdir, download, upload, cd, rm, rmdir, mkdir, mv. Note: You must first use your local sftp client to set up certifica…

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## [How to disable precompile statements while building Julia?](https://discourse.julialang.org/t/how-to-disable-precompile-statements-while-building-julia/103461)

<div class="topic-metadata">

**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 2\
**Last updated:** [September 2, 2023, 12:15pm UTC](https://discourse.julialang.org/t/how-to-disable-precompile-statements-while-building-julia/103461 "2023-09-02T12:15:24Z")

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I have added a Make.user with the content $ cat Make.user JULIA\_PRECOMPILE ?= 0 but when I build Julia (using make), I find Collecting and executing precompile statements └ Collect (Basic: ✓ 871, REPL 39/39: ✓ 1862) =\>…

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## [Concrete class' type method not found error](https://discourse.julialang.org/t/concrete-class-type-method-not-found-error/103432)

<div class="topic-metadata">

**Author:** [@bryaan](https://discourse.julialang.org/u/bryaan)\
**Replies:** 6\
**Last updated:** [September 2, 2023, 11:36am UTC](https://discourse.julialang.org/t/concrete-class-type-method-not-found-error/103432 "2023-09-02T11:36:11Z")

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How do I create a method in a supertype MyModel that uses a datetime method defined on child type? module M2 module M1 export MyModel abstract type MyModel end Base.isless(x::MyModel, y::…

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