# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1063

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

**Page:** 1064

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## [Put!(remotechannel, x) causes no error but an infinite run time](https://discourse.julialang.org/t/put-remotechannel-x-causes-no-error-but-an-infinite-run-time/79770)

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**Author:** [@Himbeersternchen](https://discourse.julialang.org/u/Himbeersternchen)\
**Replies:** 3\
**Last updated:** [April 21, 2022, 10:48am UTC](https://discourse.julialang.org/t/put-remotechannel-x-causes-no-error-but-an-infinite-run-time/79770 "2022-04-21T10:48:11Z")

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Hi Everyone, i m trying to use RemoteChannel in Julia: julia -p 2 x = RemoteChannel(()-\>Channel{Array{Float64,2}}(1)) a = \[1 2 3 4; 5 6 7 8\] put!(x,a) ran perfect. But the maximal length of channel x is 1. So i expe…

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## [Fast offset matrix subtraction](https://discourse.julialang.org/t/fast-offset-matrix-subtraction/79731)

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**Author:** [@this\_josh](https://discourse.julialang.org/u/this_josh)\
**Replies:** 5\
**Last updated:** [April 21, 2022, 7:34am UTC](https://discourse.julialang.org/t/fast-offset-matrix-subtraction/79731 "2022-04-21T07:34:54Z")

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I have a matrix h \\in \\mathbb{R}^{n\_n \\times n\_t} where n\_n is the number of sensors and n\_t is the number of hours in a day. I want to understand the variation between each timestamp for each sensor (note times roll ove…

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## [Why does setting JULIA\_EXLCUSIVE=1 make MKL run single-threaded?](https://discourse.julialang.org/t/why-does-setting-julia-exlcusive-1-make-mkl-run-single-threaded/79766)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [April 21, 2022, 7:22am UTC](https://discourse.julialang.org/t/why-does-setting-julia-exlcusive-1-make-mkl-run-single-threaded/79766 "2022-04-21T07:22:49Z")

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I am working on a cluster with 28 cores allocated to me. I start Julia using MKL\_DYNAMIC="FALSE" JULIA\_EXCLUSIVE=1 julia although I’m uncertain if this is the right approach. Eventually, I aim to run multiple julia th…

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## [Struct constructors with partial types](https://discourse.julialang.org/t/struct-constructors-with-partial-types/79760)

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**Author:** [@tictaccat](https://discourse.julialang.org/u/tictaccat)\
**Replies:** 3\
**Last updated:** [April 21, 2022, 5:41am UTC](https://discourse.julialang.org/t/struct-constructors-with-partial-types/79760 "2022-04-21T05:41:41Z")

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Suppose I make a struct as follows struct MyStruct{A,B} x::A y::B end Why is it that the following two constructions work: julia\> MyStruct(3,4) MyStruct{Int64, Int64}(3, 4) julia\> MyStruct{Int64, Int64}(…

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## [Writing a QP to MPS?](https://discourse.julialang.org/t/writing-a-qp-to-mps/79764)

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**Author:** [@gleyland](https://discourse.julialang.org/u/gleyland)\
**Replies:** 1\
**Last updated:** [April 21, 2022, 5:40am UTC](https://discourse.julialang.org/t/writing-a-qp-to-mps/79764 "2022-04-21T05:40:15Z")

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Hi, As far as I can tell, you can’t write a QP to an MPS file with write\_to\_file, but I’ve told that MPS does support QPs. Are either of those correct? (ie, should I be able to write QP to MPS, but I’m doing it wrong, …

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## [Converting abstract types](https://discourse.julialang.org/t/converting-abstract-types/79763)

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**Author:** [@tictaccat](https://discourse.julialang.org/u/tictaccat)\
**Replies:** 1\
**Last updated:** [April 21, 2022, 5:13am UTC](https://discourse.julialang.org/t/converting-abstract-types/79763 "2022-04-21T05:13:25Z")

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Suppose I have an abstract type A{V} and two structs B{V} and C{V}, for example abstract type A{V} end struct B{V} \<: A{V} x::V end struct C{V} \<: A{V} x::V end Now suppose I have a function f that accepts A{V}.…

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## [String to Date](https://discourse.julialang.org/t/string-to-date/79741)

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**Author:** [@gjh](https://discourse.julialang.org/u/gjh)\
**Replies:** 4\
**Last updated:** [April 20, 2022, 8:20pm UTC](https://discourse.julialang.org/t/string-to-date/79741 "2022-04-20T20:20:09Z")

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Thank you for any help with this. When I convert this string to Date I get the below format. What am I doing wrong? Why can’t I get “yyyy-mm-dd”? Thank you! using Dates, DataFrames id = \[1, 2, 3, 4, 5\] bday = \[“8/23/…

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## [Getting ChainRules to work with custom Dense and Chain regularization functions](https://discourse.julialang.org/t/getting-chainrules-to-work-with-custom-dense-and-chain-regularization-functions/79334)

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**Author:** [@user22](https://discourse.julialang.org/u/user22)\
**Replies:** 2\
**Last updated:** [April 20, 2022, 7:46pm UTC](https://discourse.julialang.org/t/getting-chainrules-to-work-with-custom-dense-and-chain-regularization-functions/79334 "2022-04-20T19:46:45Z")

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I have encountered a few issues when trying to implement a regularizer function and its pullback in ChainRules to a mildly customized Flux Dense layer and Chain. For simplicity and testing purposes, I just wrote a basic …

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## [Pass expression to manipulate local variable](https://discourse.julialang.org/t/pass-expression-to-manipulate-local-variable/79652)

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**Author:** [@FireCrumb](https://discourse.julialang.org/u/FireCrumb)\
**Replies:** 22\
**Last updated:** [April 20, 2022, 7:25pm UTC](https://discourse.julialang.org/t/pass-expression-to-manipulate-local-variable/79652 "2022-04-20T19:25:54Z")

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Hi! I want to pass an Expr to a function, so it will be able to interact with local variables inside the function. What is the correct way to construct such an expression? Here’s the basic structure of my function that…

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## [Module hasproperty, getproperty Inconsistency](https://discourse.julialang.org/t/module-hasproperty-getproperty-inconsistency/79737)

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**Author:** [@AlexFreik](https://discourse.julialang.org/u/AlexFreik)\
**Replies:** 10\
**Last updated:** [April 20, 2022, 7:11pm UTC](https://discourse.julialang.org/t/module-hasproperty-getproperty-inconsistency/79737 "2022-04-20T19:11:40Z")

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When I use getproperty of :sin in Main I get some results: julia\> getproperty(Main, :sin) sin (generic function with 13 methods) But when I am trying to use hasproperty: julia\> hasproperty(Main, :sin) false My questi…

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## [Reality check: How useful exactly are SuiteSparse and LDLFactorizations' LDLT?](https://discourse.julialang.org/t/reality-check-how-useful-exactly-are-suitesparse-and-ldlfactorizations-ldlt/79607)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 11\
**Last updated:** [April 20, 2022, 5:57pm UTC](https://discourse.julialang.org/t/reality-check-how-useful-exactly-are-suitesparse-and-ldlfactorizations-ldlt/79607 "2022-04-20T17:57:37Z")

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https://github.com/JuliaSmoothOptimizers/LDLFactorizations.jl/issues/101 I realize that calling for a native implementation of a multi-frontal or supernodal factorization is a tall order: people spend decades of their …

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## [Problem simulating Matlab ODE15s in Julia](https://discourse.julialang.org/t/problem-simulating-matlab-ode15s-in-julia/79687)

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**Author:** [@BinaryBot](https://discourse.julialang.org/u/BinaryBot)\
**Replies:** 8\
**Last updated:** [April 20, 2022, 5:28pm UTC](https://discourse.julialang.org/t/problem-simulating-matlab-ode15s-in-julia/79687 "2022-04-20T17:28:33Z")

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Here is the code I have, using Pkg using PyCall using CSV; using DataFrames; using Dierckx;using DifferentialEquations;using LSODA;using MATLABDiffEq; using ParameterizedFunctions;using IfElse; p = \[ 1.35e-2 #k1 …

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## [Segfault when invoking Julia callback function from C](https://discourse.julialang.org/t/segfault-when-invoking-julia-callback-function-from-c/79541)

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**Author:** [@Octogonapus](https://discourse.julialang.org/u/Octogonapus)\
**Replies:** 10\
**Last updated:** [April 20, 2022, 3:51pm UTC](https://discourse.julialang.org/t/segfault-when-invoking-julia-callback-function-from-c/79541 "2022-04-20T15:51:50Z")

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I am trying to pass a Julia function to a C library (aws-c-mqtt) which will use it as a callback when an asynchronous event occurs. I am running in to trouble because some of the parameters passed to this callback appear…

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## [Heckle a Julia Developer! Featuring Kiran Pamnany, Relational-AI! Cambridge Julia User's Meetup](https://discourse.julialang.org/t/heckle-a-julia-developer-featuring-kiran-pamnany-relational-ai-cambridge-julia-users-meetup/79744)

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**Author:** [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Replies:** 0\
**Last updated:** [April 20, 2022, 2:43pm UTC](https://discourse.julialang.org/t/heckle-a-julia-developer-featuring-kiran-pamnany-relational-ai-cambridge-julia-users-meetup/79744 "2022-04-20T14:43:14Z")

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Last week’s CAJUN event was a smash hit so we’ll be running another one of this series! This week it will be hosted by Julia Computing at the Spaces office in Davis Square. We will have a quick “heckle session”, i.e. a d…

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## [Reading ENVI style multispectral images with archGDAL](https://discourse.julialang.org/t/reading-envi-style-multispectral-images-with-archgdal/79702)

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**Author:** [@Arrigo\_Benedetti](https://discourse.julialang.org/u/Arrigo_Benedetti)\
**Replies:** 4\
**Last updated:** [April 20, 2022, 2:09pm UTC](https://discourse.julialang.org/t/reading-envi-style-multispectral-images-with-archgdal/79702 "2022-04-20T14:09:13Z")

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I have several multispectral images with separate ENVI style header text files and I would like to load them with archGDAL.jl. I looked at the documentation of archGDAL.read() but I could not find how to do it. Maybe arc…

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## [Unicode in command line](https://discourse.julialang.org/t/unicode-in-command-line/79735)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 4\
**Last updated:** [April 20, 2022, 1:02pm UTC](https://discourse.julialang.org/t/unicode-in-command-line/79735 "2022-04-20T13:02:10Z")

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Hello, When I use UnicodePlots in the command prompt opened by executing julia.exe (1.7.2, windows 10), I get this I was wondering if this is normal or if there’s a configuration somewhere that can enable unicode cha…

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## [Plots.jl: Change formating of logscale ticks to normal formatting](https://discourse.julialang.org/t/plots-jl-change-formating-of-logscale-ticks-to-normal-formatting/79733)

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**Author:** [@loonatick-src](https://discourse.julialang.org/u/loonatick-src)\
**Replies:** 2\
**Last updated:** [April 20, 2022, 12:08pm UTC](https://discourse.julialang.org/t/plots-jl-change-formating-of-logscale-ticks-to-normal-formatting/79733 "2022-04-20T12:08:33Z")

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Consider the following plot using Plots pyplot() radix\_range\_xticks = -4:4 radix\_range = LinRange(-4, 4, 100) xs = 2.0 .^ radix\_range\_xticks pf = 50.0 bw = 25.0 roofline(x, bw, pf) = min(bw\*x, pf) ys = roofline.(xs, bw…

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## [What is the interface for abstract types in Base?](https://discourse.julialang.org/t/what-is-the-interface-for-abstract-types-in-base/79729)

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**Author:** [@melonedo](https://discourse.julialang.org/u/melonedo)\
**Replies:** 2\
**Last updated:** [April 20, 2022, 11:14am UTC](https://discourse.julialang.org/t/what-is-the-interface-for-abstract-types-in-base/79729 "2022-04-20T11:14:23Z")

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Julia has a well-defined interface for AbstractArray related in the documentation, however, I have difficulty finding interface for: AbstractString: displaying it requires ncodeunits(s::SomeString), iterate(s::SomeStr…

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## [Warmstart in \`COSMO.jl\` with \`JuMP\`](https://discourse.julialang.org/t/warmstart-in-cosmo-jl-with-jump/79727)

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**Author:** [@wujinq](https://discourse.julialang.org/u/wujinq)\
**Replies:** 1\
**Last updated:** [April 20, 2022, 9:58am UTC](https://discourse.julialang.org/t/warmstart-in-cosmo-jl-with-jump/79727 "2022-04-20T09:58:37Z")

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I’m currently using COSMO.jl to do a large scale SDP with JuMP as the interface. Is it possible to store the status of model for example every 100000 iterations, and if max\_iter is reached, to start from the starting sta…

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## [Is it suggested to write functions for ::IO?](https://discourse.julialang.org/t/is-it-suggested-to-write-functions-for-io/79718)

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**Author:** [@Rratic](https://discourse.julialang.org/u/Rratic)\
**Replies:** 6\
**Last updated:** [April 20, 2022, 9:38am UTC](https://discourse.julialang.org/t/is-it-suggested-to-write-functions-for-io/79718 "2022-04-20T09:38:55Z")

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I found that some of the functions in Base are written like (::IO,::Any), and then uses sprint to wrap it so that it can return a string. For the following code: function A(io::IO) print(io,"foo") end A()=sprint(A) B()…

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## [List Comprehension and Map](https://discourse.julialang.org/t/list-comprehension-and-map/79502)

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**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 8\
**Last updated:** [April 20, 2022, 9:21am UTC](https://discourse.julialang.org/t/list-comprehension-and-map/79502 "2022-04-20T09:21:12Z")

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I know there are a number of topics already open on this subject, but I haven’t found this specific pattern yet. I think I’m look for the map do equivalent of conditional array comprehension. Here’s a small example and …

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## [Correct process to use julia code from C# or VB .NET](https://discourse.julialang.org/t/correct-process-to-use-julia-code-from-c-or-vb-net/58018)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 28\
**Last updated:** [April 20, 2022, 8:36am UTC](https://discourse.julialang.org/t/correct-process-to-use-julia-code-from-c-or-vb-net/58018 "2022-04-20T08:36:42Z")

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I am currently working on a projet involving julia as a base language for mathematical computations, and .NET (C# or VB) for the GUI part. I want to emphasize the fact that I am quite new to dll handling, julia and .NET…

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## [Calculate area of a raster](https://discourse.julialang.org/t/calculate-area-of-a-raster/79223)

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**Author:** [@ahmoreira](https://discourse.julialang.org/u/ahmoreira)\
**Replies:** 4\
**Last updated:** [April 20, 2022, 8:30am UTC](https://discourse.julialang.org/t/calculate-area-of-a-raster/79223 "2022-04-20T08:30:43Z")

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Hi all, I am trying to calculate the area of urban land cover only for cells in which 100% of the cell is urban cover. I am calculating the area as the product of the resolution times the number of cells, but it is a bi…

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## [Updating an old model and running into deprecation and getting errors I have fixed a lot, tic toc problem here what is the best solution to replace?](https://discourse.julialang.org/t/updating-an-old-model-and-running-into-deprecation-and-getting-errors-i-have-fixed-a-lot-tic-toc-problem-here-what-is-the-best-solution-to-replace/79694)

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**Author:** [@34MidwayMonsta](https://discourse.julialang.org/u/34MidwayMonsta)\
**Replies:** 3\
**Last updated:** [April 20, 2022, 8:15am UTC](https://discourse.julialang.org/t/updating-an-old-model-and-running-into-deprecation-and-getting-errors-i-have-fixed-a-lot-tic-toc-problem-here-what-is-the-best-solution-to-replace/79694 "2022-04-20T08:15:13Z")

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Calculating baseball linueps. 3 lineups Formulation baseball\_formulation Overlap = 6 Stack size = 5 LoadError: UndefVarError: tic not defined in expression starting at C:\\Users\\Carlos Soto\\Daily-Fantasy-Baseball-C…

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## [Autocomplete in JupyterLab](https://discourse.julialang.org/t/autocomplete-in-jupyterlab/79723)

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**Author:** [@maajdl](https://discourse.julialang.org/u/maajdl)\
**Replies:** 0\
**Last updated:** [April 20, 2022, 7:39am UTC](https://discourse.julialang.org/t/autocomplete-in-jupyterlab/79723 "2022-04-20T07:39:42Z")

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Hello I realised that “Autocomplete” doesn’t work in my JupyterLab. It works for Python, but not for Julia. With Julia, the TAB key just displaces the cursor, but no autocomplete. Is that just a small settings proble…

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## [What is empty index notation?](https://discourse.julialang.org/t/what-is-empty-index-notation/79676)

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**Author:** [@Katamari](https://discourse.julialang.org/u/Katamari)\
**Replies:** 8\
**Last updated:** [April 20, 2022, 7:08am UTC](https://discourse.julialang.org/t/what-is-empty-index-notation/79676 "2022-04-20T07:08:19Z")

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I saw the following notation in the documentation of Makie. x\[\] = 3.34 https://makie.juliaplots.org/stable/documentation/nodes/index.html#the\_observable\_structure What is this syntax?

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## [Understanding the startup.jl file -- is there a environment-specific version?](https://discourse.julialang.org/t/understanding-the-startup-jl-file-is-there-a-environment-specific-version/77998)

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**Author:** [@Jason\_Mercer](https://discourse.julialang.org/u/Jason_Mercer)\
**Replies:** 9\
**Last updated:** [April 20, 2022, 3:30am UTC](https://discourse.julialang.org/t/understanding-the-startup-jl-file-is-there-a-environment-specific-version/77998 "2022-04-20T03:30:18Z")

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My understanding of the startup.jl file is that it applies to all Julia instances/environments and there is no way to apply different startup scripts to different environments. I tried including a local startup.jl file i…

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## [LOAD\_PATH includes unquoted individual entries](https://discourse.julialang.org/t/load-path-includes-unquoted-individual-entries/57746)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 10\
**Last updated:** [March 23, 2021, 7:46am UTC](https://discourse.julialang.org/t/load-path-includes-unquoted-individual-entries/57746 "2021-03-23T07:46:47Z")

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It seems that somehow individual entries in LOAD\_PATH are not quoted: lobianco@NCY-BETA-ALOBIANCO:~/.julia/dev/BetaML$ cd "docs/src/tutorials/A regression task: sharing bike demand prediction" lobianco@NCY-BETA-ALOBIANC…

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## [Manual RNN on GPU](https://discourse.julialang.org/t/manual-rnn-on-gpu/79580)

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**Author:** [@kailukowiak](https://discourse.julialang.org/u/kailukowiak)\
**Replies:** 3\
**Last updated:** [April 20, 2022, 12:29am UTC](https://discourse.julialang.org/t/manual-rnn-on-gpu/79580 "2022-04-20T00:29:59Z")

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I’m trying to redo this tutorial in Flux. The neural net runs fine on a CPU but when I try transferring it to the GPU I get an error which is caused by indexing a CUDA array. Here’s an MRE: ## using Flux using Flux: on…

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## [Tracing functions, inverse of Meta.parse?](https://discourse.julialang.org/t/tracing-functions-inverse-of-meta-parse/79705)

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**Author:** [@Mark\_Nahabedian](https://discourse.julialang.org/u/Mark_Nahabedian)\
**Replies:** 1\
**Last updated:** [April 20, 2022, 12:03am UTC](https://discourse.julialang.org/t/tracing-functions-inverse-of-meta-parse/79705 "2022-04-20T00:03:28Z")

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I’ve not found a function tracing facility for Julia so I’m trying to implement a simple one. My idea is to have a macro,@trace, that prefixes a method definition and alters that definition to start with a log message t…

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