# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1535

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

**Page:** 1536

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## [How to solve Lambert W function?](https://discourse.julialang.org/t/how-to-solve-lambert-w-function/52538)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 17\
**Last updated:** [December 29, 2020, 3:48pm UTC](https://discourse.julialang.org/t/how-to-solve-lambert-w-function/52538 "2020-12-29T15:48:07Z")

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I have this equation Nₜ₊₁ = Nₜ exp\[μ(1-Nₜ/K)\] I would like to solve it the other way round: knowing Nₜ₊₁, I would like to estimate Nₜ. This is in the form y = x exp(a(1−x/k)) From this post looks like the solution is…

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## [Is it possible to use Julia as a co-simulator in conjunction to PSCAD/EMTDC or MATLAB](https://discourse.julialang.org/t/is-it-possible-to-use-julia-as-a-co-simulator-in-conjunction-to-pscad-emtdc-or-matlab/52516)

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**Author:** [@anchasatish](https://discourse.julialang.org/u/anchasatish)\
**Replies:** 2\
**Last updated:** [December 29, 2020, 2:10pm UTC](https://discourse.julialang.org/t/is-it-possible-to-use-julia-as-a-co-simulator-in-conjunction-to-pscad-emtdc-or-matlab/52516 "2020-12-29T14:10:41Z")

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I want to use Julia programming for running optimization of the system whose dynamic modeling is made in EMTDC/PSCAD, or MATLAB, i.e., optimization problem solved in Julia and output of this optimization solution is give…

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## [Package development - guide required for good resources](https://discourse.julialang.org/t/package-development-guide-required-for-good-resources/52490)

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**Author:** [@imanuelcostigan](https://discourse.julialang.org/u/imanuelcostigan)\
**Replies:** 4\
**Last updated:** [December 29, 2020, 1:53pm UTC](https://discourse.julialang.org/t/package-development-guide-required-for-good-resources/52490 "2020-12-29T13:53:53Z")

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What is the most canonical and careful presentation of the packaging infrastructure from the perspective of a package developer? I prefer text rather than video (much easier to hop into a bit precisely). Basic things lik…

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## [Bools in arithmetic operations](https://discourse.julialang.org/t/bools-in-arithmetic-operations/52504)

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**Author:** [@stephancb](https://discourse.julialang.org/u/stephancb)\
**Replies:** 8\
**Last updated:** [December 29, 2020, 1:30pm UTC](https://discourse.julialang.org/t/bools-in-arithmetic-operations/52504 "2020-12-29T13:30:14Z")

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Bools seem to get converted/promoted to numerical zero/one: julia\> false + 42 42 julia\> true + 42 43 julia\> false + 3.14 3.14 julia\> true + 3.14 4.140000000000001 julia\> false + complex(1, 2) 1 + 2im julia\> true + …

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## [Basic remote procedure call via ssh from Linux to Windows](https://discourse.julialang.org/t/basic-remote-procedure-call-via-ssh-from-linux-to-windows/18743)

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**Author:** [@mgkuhn](https://discourse.julialang.org/u/mgkuhn)\
**Replies:** 8\
**Last updated:** [December 29, 2020, 12:52pm UTC](https://discourse.julialang.org/t/basic-remote-procedure-call-via-ssh-from-linux-to-windows/18743 "2020-12-29T12:52:48Z")

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I have a Julia application running under Linux. I would like to make a couple of remote function calls to another Julia process running on a specific Windows machine, because that Windows machine has special data-acquisi…

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## [3D bin packaging using Convex.jl](https://discourse.julialang.org/t/3d-bin-packaging-using-convex-jl/52571)

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**Author:** [@adropintheriver](https://discourse.julialang.org/u/adropintheriver)\
**Replies:** 0\
**Last updated:** [December 29, 2020, 12:36pm UTC](https://discourse.julialang.org/t/3d-bin-packaging-using-convex-jl/52571 "2020-12-29T12:36:08Z")

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Intent :Write a convex function that takes a set of points of shape (m,n) basically convexhull points by reading a CAD model. The function must return a Variable(from Convex.jl) of shape/size of the original vector (to…

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## [Best route for academic purchases of current-gen GPU components (non data-center parts)](https://discourse.julialang.org/t/best-route-for-academic-purchases-of-current-gen-gpu-components-non-data-center-parts/52539)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 1\
**Last updated:** [December 29, 2020, 11:31am UTC](https://discourse.julialang.org/t/best-route-for-academic-purchases-of-current-gen-gpu-components-non-data-center-parts/52539 "2020-12-29T11:31:18Z")

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Our procurement people use KFS to order this kind of stuff via purchase-orders on cdw, newegg, etc. Needless to say current-gen components (stuff like RTX 3xxx cards) are extremely hard to find at these outlets because …

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## [Can I extend other functions to make it compatible with Convex.jl (element-wise operation)](https://discourse.julialang.org/t/can-i-extend-other-functions-to-make-it-compatible-with-convex-jl-element-wise-operation/52565)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 0\
**Last updated:** [December 29, 2020, 10:15am UTC](https://discourse.julialang.org/t/can-i-extend-other-functions-to-make-it-compatible-with-convex-jl-element-wise-operation/52565 "2020-12-29T10:15:22Z")

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I’m using Convex.jl for convex optimisation. When constructing a function that I need to optimise, I used to extend methods of Convex to make it compatible with other functions, for example, # extend Convex method func…

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## [Appending to an array along dimension n](https://discourse.julialang.org/t/appending-to-an-array-along-dimension-n/52564)

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**Author:** [@jakewilliami](https://discourse.julialang.org/u/jakewilliami)\
**Replies:** 2\
**Last updated:** [December 29, 2020, 9:52am UTC](https://discourse.julialang.org/t/appending-to-an-array-along-dimension-n/52564 "2020-12-29T09:52:04Z")

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I am trying to write a function that fills rows along the ith dimension n many times. Let’s call this function fill\_n\_times. If the function takes parameters fill\_n\_times(M, n, fill\_elem; dim = 1) Then my expected ou…

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## [How to force flux parameters to be within a certain compact set? (projection)](https://discourse.julialang.org/t/how-to-force-flux-parameters-to-be-within-a-certain-compact-set-projection/52561)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 1\
**Last updated:** [December 29, 2020, 9:15am UTC](https://discourse.julialang.org/t/how-to-force-flux-parameters-to-be-within-a-certain-compact-set-projection/52561 "2020-12-29T09:15:40Z")

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Hi, I’m trying to realise projected gradient descent-like methods. As Flux said, I constructed my custom training loop as follows, function train!(m::ICNN, loss, data, opt) ps = Flux.params(ICNN) for d in data …

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## [Indexing into multidimensional array for general n dimensions](https://discourse.julialang.org/t/indexing-into-multidimensional-array-for-general-n-dimensions/52556)

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**Author:** [@gxyd](https://discourse.julialang.org/u/gxyd)\
**Replies:** 2\
**Last updated:** [December 29, 2020, 8:11am UTC](https://discourse.julialang.org/t/indexing-into-multidimensional-array-for-general-n-dimensions/52556 "2020-12-29T08:11:18Z")

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Hi, Let’s consider an array X of two dimensions, here X\[1,1\] is of type Array{Float64, 2}, i.e. n = 2: julia\> X 2×2 Array{Array{Float64,2},2}: \[0.0 0.0; 0.0 0.0; 0.0 0.0\] \[2.0 2.0; 2.0 2.0; 2.0 2.0\] \[2.0 2.0; 2.0 2.…

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## [Julia crashes inside @threads with MPI](https://discourse.julialang.org/t/julia-crashes-inside-threads-with-mpi/52400)

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**Author:** [@Jae-Mo\_Lihm](https://discourse.julialang.org/u/Jae-Mo_Lihm)\
**Replies:** 5\
**Last updated:** [December 29, 2020, 7:41am UTC](https://discourse.julialang.org/t/julia-crashes-inside-threads-with-mpi/52400 "2020-12-29T07:41:52Z")

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Hi, I am trying to implement a program with hybrid MPI + Threads parallelization. In the following example, if I comment out all MPI-related lines, the code runs without any problem. However, if I run the code with the …

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## [ERROR: this intrinsic must be compiled to be called](https://discourse.julialang.org/t/error-this-intrinsic-must-be-compiled-to-be-called/52497)

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**Author:** [@kadir-gunel](https://discourse.julialang.org/u/kadir-gunel)\
**Replies:** 9\
**Last updated:** [December 29, 2020, 6:00am UTC](https://discourse.julialang.org/t/error-this-intrinsic-must-be-compiled-to-be-called/52497 "2020-12-29T06:00:01Z")

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Hello, For the past 2 weeks , I have been struggling with a flux model that I wrote. Since I am newbie to flux, zygote, and CuArrays, certainly, I don’t understand what is the actual problem right away. Below, I leave a…

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## [Why by default two julia process running?](https://discourse.julialang.org/t/why-by-default-two-julia-process-running/52522)

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**Author:** [@Ravinder\_Ram](https://discourse.julialang.org/u/Ravinder_Ram)\
**Replies:** 2\
**Last updated:** [December 29, 2020, 3:55am UTC](https://discourse.julialang.org/t/why-by-default-two-julia-process-running/52522 "2020-12-29T03:55:56Z")

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two julia process running

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## [Question about iterating through a for loop in Julia](https://discourse.julialang.org/t/question-about-iterating-through-a-for-loop-in-julia/52549)

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**Author:** [@Brian\_Becsi](https://discourse.julialang.org/u/Brian_Becsi)\
**Replies:** 2\
**Last updated:** [December 29, 2020, 2:39am UTC](https://discourse.julialang.org/t/question-about-iterating-through-a-for-loop-in-julia/52549 "2020-12-29T02:39:25Z")

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Hello. I am new to programming in general. I am translating some Python into Julia. There is a specific problem that’s been dogging me for like a week. I though it had it down but it’s still causing me troubles. When I…

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## [LAPACK error from quadgk integration](https://discourse.julialang.org/t/lapack-error-from-quadgk-integration/52533)

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**Author:** [@Nkrause](https://discourse.julialang.org/u/Nkrause)\
**Replies:** 5\
**Last updated:** [December 29, 2020, 2:02am UTC](https://discourse.julialang.org/t/lapack-error-from-quadgk-integration/52533 "2020-12-29T02:02:03Z")

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I’m trying to integrate the following formula. It computes an electric potential at a point from a circular ring of charge. \\phi=\\int\_0^{2\\pi} \\frac{1}{\\sqrt{(x-cos(t))^2+(y-sin(t))^2+z^2)}}dt I’ve implemented the func…

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## [Ccall printf works with ints but not with floats. Why?](https://discourse.julialang.org/t/ccall-printf-works-with-ints-but-not-with-floats-why/52487)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 7\
**Last updated:** [December 29, 2020, 12:37am UTC](https://discourse.julialang.org/t/ccall-printf-works-with-ints-but-not-with-floats-why/52487 "2020-12-29T00:37:05Z")

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julia\> ccall(:printf, Cint, (Ptr{Cchar}, Cint), "aiai %d", 10); aiai 10 julia\> ccall(:printf, Cint, (Ptr{Cchar}, Cdouble), "aiai %f", 10.99); aiai 0.000000 The context for this is to reduce invalidations that cause late…

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## [Elementwise operation with different dimensions of vectors](https://discourse.julialang.org/t/elementwise-operation-with-different-dimensions-of-vectors/52543)

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**Author:** [@rcesarpacheco](https://discourse.julialang.org/u/rcesarpacheco)\
**Replies:** 1\
**Last updated:** [December 28, 2020, 11:29pm UTC](https://discourse.julialang.org/t/elementwise-operation-with-different-dimensions-of-vectors/52543 "2020-12-28T23:29:21Z")

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I am starting to write some codes in Julia and I have some doubts about elementwise operations. Imagine that I have two matrices, A and B: A= randn(3,3,3); B = rand(3,3); When I do something like A .==B what the compi…

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## [Question about the Template type in the PkgTemplates.jl package](https://discourse.julialang.org/t/question-about-the-template-type-in-the-pkgtemplates-jl-package/52545)

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**Author:** [@florian](https://discourse.julialang.org/u/florian)\
**Replies:** 2\
**Last updated:** [December 28, 2020, 10:39pm UTC](https://discourse.julialang.org/t/question-about-the-template-type-in-the-pkgtemplates-jl-package/52545 "2020-12-28T22:39:03Z")

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Hi everyone, I have a question regarding Types/Functions that came up after I discovered the PkgTemplates.jl package. In this package I can define an object of type Template like so: t = Template(); Then, to actuall…

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## [DataFrames transform list comprehension](https://discourse.julialang.org/t/dataframes-transform-list-comprehension/52519)

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**Author:** [@ZettEff](https://discourse.julialang.org/u/ZettEff)\
**Replies:** 5\
**Last updated:** [December 28, 2020, 8:33pm UTC](https://discourse.julialang.org/t/dataframes-transform-list-comprehension/52519 "2020-12-28T20:33:19Z")

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Is there a way to achieve the below using list comprehsion? My goal is to create columns lag1 to lagN by doing \[dosomething for i in 1:N\] df = DataFrame(:ret =\> rand(100)) transform(df,:ret =\> (col -\> lag(col,1)) =\> :l…

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## [Union vs. \<: AbstractType](https://discourse.julialang.org/t/union-vs-abstracttype/52530)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 7\
**Last updated:** [December 28, 2020, 7:58pm UTC](https://discourse.julialang.org/t/union-vs-abstracttype/52530 "2020-12-28T19:58:05Z")

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This is not really a question, because I know how to use them, but the notation still makes me confuse every time. In summary, I feel that the notation Vector{T} where T \<: AbstractType suggests that a single concrete t…

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## [CI/CD without travis-ci.org](https://discourse.julialang.org/t/ci-cd-without-travis-ci-org/52501)

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**Author:** [@lobingera](https://discourse.julialang.org/u/lobingera)\
**Replies:** 8\
**Last updated:** [December 28, 2020, 6:54pm UTC](https://discourse.julialang.org/t/ci-cd-without-travis-ci-org/52501 "2020-12-28T18:54:49Z")

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I followed a little bit the topic of moving CI to github actions, but couldn’t really get the conclusion how to do this for packages in general. Afaics github is providing resources for runners and some infrastructure f…

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## [Fastest way to filter when right hand sinde of \`in\` is large](https://discourse.julialang.org/t/fastest-way-to-filter-when-right-hand-sinde-of-in-is-large/52526)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 3\
**Last updated:** [December 28, 2020, 6:48pm UTC](https://discourse.julialang.org/t/fastest-way-to-filter-when-right-hand-sinde-of-in-is-large/52526 "2020-12-28T18:48:41Z")

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I’m facing a problem where I would like to filter a dataset by using only those IDs that occur in another vector (that is around 100,000 elements long). If I just use in that takes forever as, I assume it checks every el…

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## [ERROR: LoadError: CUDNNError: CUDNN\_STATUS\_EXECUTION\_FAILED (code 8)](https://discourse.julialang.org/t/error-loaderror-cudnnerror-cudnn-status-execution-failed-code-8/52528)

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**Author:** [@vkv](https://discourse.julialang.org/u/vkv)\
**Replies:** 0\
**Last updated:** [December 28, 2020, 6:35pm UTC](https://discourse.julialang.org/t/error-loaderror-cudnnerror-cudnn-status-execution-failed-code-8/52528 "2020-12-28T18:35:23Z")

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I’m not able to get this code running on a GPU, but it works on CPU. I’ve tried different versions of CUDA, Nvidia drivers and Julia versions. Every time it ended up with the same error. As the code runs, the memory cons…

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## [Problem adding a local registry from remote](https://discourse.julialang.org/t/problem-adding-a-local-registry-from-remote/52500)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 1\
**Last updated:** [December 28, 2020, 6:03pm UTC](https://discourse.julialang.org/t/problem-adding-a-local-registry-from-remote/52500 "2020-12-28T18:03:28Z")

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I made a local registry with LocalRegistry.jl, and set its remote in a private network to share it with colleagues. I can work with that local registry without problems, but other people have problems when they try to ad…

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## [Configuring the view of the REPL and plots in VSCode](https://discourse.julialang.org/t/configuring-the-view-of-the-repl-and-plots-in-vscode/52381)

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**Author:** [@Michael\_Barmann](https://discourse.julialang.org/u/Michael_Barmann)\
**Replies:** 2\
**Last updated:** [December 28, 2020, 5:12pm UTC](https://discourse.julialang.org/t/configuring-the-view-of-the-repl-and-plots-in-vscode/52381 "2020-12-28T17:12:49Z")

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I just created my first plot in Julia using the VSCode editor, and I’m trying to figure out how to change the appearance of the plot display and the REPL so that they are stacked on top of each other on the right hand si…

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## [JuliaPro1.5.0: could not download https://pkg.juliahub.com/registries](https://discourse.julialang.org/t/juliapro1-5-0-could-not-download-https-pkg-juliahub-com-registries/44811)

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**Author:** [@zwwi](https://discourse.julialang.org/u/zwwi)\
**Replies:** 21\
**Last updated:** [December 28, 2020, 4:45pm UTC](https://discourse.julialang.org/t/juliapro1-5-0-could-not-download-https-pkg-juliahub-com-registries/44811 "2020-12-28T16:45:14Z")

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Today I installed the new version of JuliaPro, but met the issue Warning: could not download https://pkg.juliahub.com/registries └ @ Pkg.Types D:\\buildbot\\worker\\package\_win64\\build\\usr\\share\\julia\\stdlib\\v1.5\\Pkg\\src\\…

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## [Call C++ library](https://discourse.julialang.org/t/call-c-library/51856)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 4\
**Last updated:** [December 28, 2020, 4:36pm UTC](https://discourse.julialang.org/t/call-c-library/51856 "2020-12-28T16:36:51Z")

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I want to control this equipment using the libraries provided by the manufacturer: libm2k: libm2k::analog::DMM Class Reference I tried to install Cxx on Julia 1.5 but I got and error: julia\> using Cxx \[ Info: Precompil…

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## [How to access files outside home folder (VSCode remote)](https://discourse.julialang.org/t/how-to-access-files-outside-home-folder-vscode-remote/52505)

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**Author:** [@Luapulu](https://discourse.julialang.org/u/Luapulu)\
**Replies:** 2\
**Last updated:** [December 28, 2020, 2:05pm UTC](https://discourse.julialang.org/t/how-to-access-files-outside-home-folder-vscode-remote/52505 "2020-12-28T14:05:16Z")

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So, I’m connected to a remote server via ssh in VSCode. Problem is, I can’t access files outside my (remote) home directory from the juia REPL. When I copy files into my home directory I can access them. I assume this i…

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## [Can indexes to DataFrame column be added to inprove selection performances?](https://discourse.julialang.org/t/can-indexes-to-dataframe-column-be-added-to-inprove-selection-performances/52456)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [December 28, 2020, 1:11pm UTC](https://discourse.julialang.org/t/can-indexes-to-dataframe-column-be-added-to-inprove-selection-performances/52456 "2020-12-28T13:11:30Z")

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In relational databases like mysql we have the option to add “indexes” to columns in order to increase selection performances (at cost of worsening them when editing the data). Is there an option to add indexes to Julia…

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