# Latest

**URL:** https://discourse.julialang.org/latest.md?page=483

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

**Page:** 484

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## [Why can't I use \`subtypes\` in a test?](https://discourse.julialang.org/t/why-cant-i-use-subtypes-in-a-test/110235)

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**Author:** [@GHTaarn](https://discourse.julialang.org/u/GHTaarn)\
**Replies:** 1\
**Last updated:** [February 15, 2024, 5:25am UTC](https://discourse.julialang.org/t/why-cant-i-use-subtypes-in-a-test/110235 "2024-02-15T05:25:53Z")

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I tried to use the subtypes function in a test, e.g.: using Test @test subtypes(Real) != 0 This works in the REPL, but in a package test this fails with: UndefVarError: \`subtypes\` not defined Can someone explain why…

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## [Tullio & AxisKeys can dummy variables refer to named keys](https://discourse.julialang.org/t/tullio-axiskeys-can-dummy-variables-refer-to-named-keys/110233)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 0\
**Last updated:** [February 15, 2024, 4:31am UTC](https://discourse.julialang.org/t/tullio-axiskeys-can-dummy-variables-refer-to-named-keys/110233 "2024-02-15T04:31:57Z")

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Is there a more succinct way to do this? ka = KeyedArray( ones(2,2), I=\[:a,:b\], J=\[:x,:y\] ) @tullio x\[i,j\] := ( ka\[i,j\], axiskeys(ka)\[1\]\[i\], axiskeys(ka)\[2\]\[j\]) Something like @tullio x\[i,j\] := ( ka(i,j), i, j ) T…

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## [Slow LSTM on GPU in Flux](https://discourse.julialang.org/t/slow-lstm-on-gpu-in-flux/84228)

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**Author:** [@JLDC](https://discourse.julialang.org/u/JLDC)\
**Replies:** 21\
**Last updated:** [February 15, 2024, 2:14am UTC](https://discourse.julialang.org/t/slow-lstm-on-gpu-in-flux/84228 "2024-02-15T02:14:58Z")

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Hi, I’ve been running into an issue where I try to train a neural network using Flux and the training times are much slower on GPU than on CPU. So I tried comparing an MWE using Flux and an MWE using PyCall and running …

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## [Lux.jl LSTM timeseries prediction: AD / optimization does not start](https://discourse.julialang.org/t/lux-jl-lstm-timeseries-prediction-ad-optimization-does-not-start/107553)

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**Author:** [@OliverWallscheid](https://discourse.julialang.org/u/OliverWallscheid)\
**Replies:** 2\
**Last updated:** [February 14, 2024, 10:50pm UTC](https://discourse.julialang.org/t/lux-jl-lstm-timeseries-prediction-ad-optimization-does-not-start/107553 "2024-02-14T22:50:50Z")

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Hey there, I am trying to compile a training session of a simple time series prediction example using a LSTM cell within a Lux chain. My model is model = Lux.Chain(Lux.Dense(2 =\> 2), Lux.Recurrence(Lux.LSTMCell(2 =\> 2…

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## [Function definition inside let-block impacting performance?](https://discourse.julialang.org/t/function-definition-inside-let-block-impacting-performance/110007)

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**Author:** [@JuhaHeiskala](https://discourse.julialang.org/u/JuhaHeiskala)\
**Replies:** 42\
**Last updated:** [February 14, 2024, 10:18pm UTC](https://discourse.julialang.org/t/function-definition-inside-let-block-impacting-performance/110007 "2024-02-14T22:18:36Z")

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Is there some reason why a function defined inside a let-block is slower compared to defining the same function in global scope? e.g. below recursive Fibonacci (from the old Julia microbenchmarks) is 10 times slower if …

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## [Julia v1.10.1 has been released](https://discourse.julialang.org/t/julia-v1-10-1-has-been-released/110227)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 0\
**Last updated:** [February 14, 2024, 10:03pm UTC](https://discourse.julialang.org/t/julia-v1-10-1-has-been-released/110227 "2024-02-14T22:03:30Z")

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Julia version 1.10.1, the first patch release in the 1.10 series of releases, is now available. Binaries are available via Juliaup and at https://julialang.org/downloads/ for macOS (Intel and M-series processors), Window…

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## [Conversion and promotion](https://discourse.julialang.org/t/conversion-and-promotion/110217)

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**Author:** [@hros](https://discourse.julialang.org/u/hros)\
**Replies:** 2\
**Last updated:** [February 14, 2024, 9:54pm UTC](https://discourse.julialang.org/t/conversion-and-promotion/110217 "2024-02-14T21:54:06Z")

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While working on an exercise on exercism, I found myself struggling with the issue of conversion and promotion. The exercise called for implementing a user-defined type for complex numbers. Defining the type and the mat…

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## [Algorithm for product of vectors](https://discourse.julialang.org/t/algorithm-for-product-of-vectors/110049)

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**Author:** [@blociss](https://discourse.julialang.org/u/blociss)\
**Replies:** 32\
**Last updated:** [February 14, 2024, 8:39pm UTC](https://discourse.julialang.org/t/algorithm-for-product-of-vectors/110049 "2024-02-14T20:39:26Z")

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Consider uu=\[ \[ ((1, 2), (3, -2)), ((1, 3), (3, -3))\], \[ ((1, -1), (2, 1))\], \[((1, 1), (2, -1)), ((1, -1), (2, 1))\], \[ ((2, -2), (4, 2)), ((2, -3), (4, 3))\], \[((3, 1), (4, -1)), ((3, 4), (4, -4))\], \[((3, 1), (4, …

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## [Change "current working module" from REPL](https://discourse.julialang.org/t/change-current-working-module-from-repl/53166)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 6\
**Last updated:** [February 14, 2024, 8:26pm UTC](https://discourse.julialang.org/t/change-current-working-module-from-repl/53166 "2024-02-14T20:26:42Z")

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In package development, I often find myself needing to bring lots of things into scope, so I can run bits and pieces as if my package were running them. Something like julia\> using Foo # or some package I'm developing j…

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## [How to pass a matrix free preconditioner to IterativeSolver of KrylovKit?](https://discourse.julialang.org/t/how-to-pass-a-matrix-free-preconditioner-to-iterativesolver-of-krylovkit/63315)

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**Author:** [@FredericN](https://discourse.julialang.org/u/FredericN)\
**Replies:** 6\
**Last updated:** [February 14, 2024, 8:04pm UTC](https://discourse.julialang.org/t/how-to-pass-a-matrix-free-preconditioner-to-iterativesolver-of-krylovkit/63315 "2024-02-14T20:04:54Z")

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Say I have a matrix A and a linear function P that takes as argument a vector and returns a vector of the same size. How can I use a preconditioned conjugate gradient from IterativeSolver.jl of KrylovKit.jl for solving A…

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## [Better way to name or inherit parameters with NonlinearSolve.jl?](https://discourse.julialang.org/t/better-way-to-name-or-inherit-parameters-with-nonlinearsolve-jl/110213)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 3\
**Last updated:** [February 14, 2024, 7:08pm UTC](https://discourse.julialang.org/t/better-way-to-name-or-inherit-parameters-with-nonlinearsolve-jl/110213 "2024-02-14T19:08:05Z")

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I am using NonlinearSolve.jl for simple interval root finding. It is working well, but the way I am handling parameters is sticking out to me like a code smell. Is there a better way to pack and unpack the parameter ve…

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## [Bind values from multiple HTML fields in Pluto](https://discourse.julialang.org/t/bind-values-from-multiple-html-fields-in-pluto/110022)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 4\
**Last updated:** [February 14, 2024, 7:05pm UTC](https://discourse.julialang.org/t/bind-values-from-multiple-html-fields-in-pluto/110022 "2024-02-14T19:05:54Z")

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Hello, I would like to organize a grid of number fields in a cell and assign each input to a different julia variable (or perhaps a dictionary). What is the best way to do that? I attached example code below. Thank you…

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## [X' allowed in JuMP model but not transpose(X)](https://discourse.julialang.org/t/x-allowed-in-jump-model-but-not-transpose-x/110147)

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**Author:** [@dhendryc](https://discourse.julialang.org/u/dhendryc)\
**Replies:** 3\
**Last updated:** [February 14, 2024, 6:39pm UTC](https://discourse.julialang.org/t/x-allowed-in-jump-model-but-not-transpose-x/110147 "2024-02-14T18:39:37Z")

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Hi, I have encountered a weird behaviour in JuMP. This works JuMP.@constraint(model, sum(A\[i, :\] \* Y\_mat\[i,:\]’ for i in 1:m) .- sum(μ)\*I .== zeros(n,n)) while this does not JuMP.@constraint(model, sum(A\[i, :\] \* tran…

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## [Using NVIDIA Nsight Systems](https://discourse.julialang.org/t/using-nvidia-nsight-systems/110220)

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**Author:** [@Rabab53](https://discourse.julialang.org/u/Rabab53)\
**Replies:** 1\
**Last updated:** [February 14, 2024, 6:27pm UTC](https://discourse.julialang.org/t/using-nvidia-nsight-systems/110220 "2024-02-14T18:27:33Z")

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Hello, I am trying to use CUDA profile using Nsight Systems, but I facing some issues with some warning. I am using (2024.1.1.59) version of Nsight Systems. omairyrm@vulture:~/Julia\_rabab$ nsys launch julia …

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## [Time Dependent Linear Map](https://discourse.julialang.org/t/time-dependent-linear-map/110192)

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**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 5\
**Last updated:** [February 14, 2024, 5:43pm UTC](https://discourse.julialang.org/t/time-dependent-linear-map/110192 "2024-02-14T17:43:04Z")

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I am trying to implement an initial problem. Let the system of ODEs be \\frac{d\\vec{y}}{dt} = A(t;\\vec{\\theta})\\vec{y}, \\quad \\vec{y}(0) = \\vec{y}\_0, \\quad 0 \\leq t \\leq T. The matrix A depends on the time t, as well a…

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## [Possible compiler issue with enzyme and custom data type](https://discourse.julialang.org/t/possible-compiler-issue-with-enzyme-and-custom-data-type/110125)

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**Author:** [@jwalker](https://discourse.julialang.org/u/jwalker)\
**Replies:** 6\
**Last updated:** [February 14, 2024, 5:30pm UTC](https://discourse.julialang.org/t/possible-compiler-issue-with-enzyme-and-custom-data-type/110125 "2024-02-14T17:30:52Z")

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I had some tests for a custom data type that were working last Friday. Now, one test doesn’t work, and I’m very confused about what changed. I suspect that there might be an issue with Enzyme and the compiler. I don’t h…

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## [Solve linear systems inside CUDA kernel function](https://discourse.julialang.org/t/solve-linear-systems-inside-cuda-kernel-function/110202)

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**Author:** [@FR13ndSDP](https://discourse.julialang.org/u/FR13ndSDP)\
**Replies:** 8\
**Last updated:** [February 14, 2024, 4:54pm UTC](https://discourse.julialang.org/t/solve-linear-systems-inside-cuda-kernel-function/110202 "2024-02-14T16:54:12Z")

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Hello everyone, I was wondering how to solve a small linear system Ax = b inside a CUDA kernel function, where A, x and b are MMatrix and MVector. I want to do this with x = A\\b, but it does not work inside a kernel, is …

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## [VSCode gives Node.js "open EISDIR" error when opening file from REPL](https://discourse.julialang.org/t/vscode-gives-node-js-open-eisdir-error-when-opening-file-from-repl/108540)

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**Author:** [@mikmoore](https://discourse.julialang.org/u/mikmoore)\
**Replies:** 5\
**Last updated:** [February 14, 2024, 4:34pm UTC](https://discourse.julialang.org/t/vscode-gives-node-js-open-eisdir-error-when-opening-file-from-repl/108540 "2024-02-14T16:34:23Z")

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Several months ago, I started getting an error when I use control+q to open a location in a stack trace or method list after entering an index into that list on the REPL any time I attempt to open a file from the REPL wh…

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## [Constrained partitions of 1:K](https://discourse.julialang.org/t/constrained-partitions-of-1-k/109952)

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**Author:** [@clempe](https://discourse.julialang.org/u/clempe)\
**Replies:** 2\
**Last updated:** [February 14, 2024, 3:37pm UTC](https://discourse.julialang.org/t/constrained-partitions-of-1-k/109952 "2024-02-14T15:37:46Z")

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i’m trying to find all partitions of 1:K that satisfy some criteria: take all partitions so that there are n subsets of size 2, h subsets of size 3, and all other subsets singletons. I can probably come up with somethi…

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## [Heatmap wrong colorbar number resolution limits](https://discourse.julialang.org/t/heatmap-wrong-colorbar-number-resolution-limits/110209)

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**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 4\
**Last updated:** [February 14, 2024, 3:33pm UTC](https://discourse.julialang.org/t/heatmap-wrong-colorbar-number-resolution-limits/110209 "2024-02-14T15:33:14Z")

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Hello, good morning I’m having some diffucults plotting a covariance matrix with low values. The colorbar always shows zero, and cant acquire the correct values. There are configurations thats solves this issue? let…

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## [Please someone explain me the array indexing example from manual?](https://discourse.julialang.org/t/please-someone-explain-me-the-array-indexing-example-from-manual/110174)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 5\
**Last updated:** [February 14, 2024, 1:48pm UTC](https://discourse.julialang.org/t/please-someone-explain-me-the-array-indexing-example-from-manual/110174 "2024-02-14T13:48:31Z")

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I am truly lost at following example. I appreciate any directions, I seem to understand all previous examples, but this one just made me dazzle. Julia 1.10 manual array indexing section If I\_1 is changed to a two-dime…

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## [This function seems to allocate memory only if the argument types are not annotated in the definition](https://discourse.julialang.org/t/this-function-seems-to-allocate-memory-only-if-the-argument-types-are-not-annotated-in-the-definition/110193)

<div class="topic-metadata">

**Author:** [@Joaquin\_Rodriguez](https://discourse.julialang.org/u/Joaquin_Rodriguez)\
**Replies:** 5\
**Last updated:** [February 14, 2024, 1:41pm UTC](https://discourse.julialang.org/t/this-function-seems-to-allocate-memory-only-if-the-argument-types-are-not-annotated-in-the-definition/110193 "2024-02-14T13:41:17Z")

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I am defining a custom data type that behaves like a vector (in the linear algebra sense). I defined it as a structure with a 6-element StaticVector that holds the underlying data: using StaticArrays struct MyVectorTyp…

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## [PlutoPlotly: save a plot with LaTeX strings](https://discourse.julialang.org/t/plutoplotly-save-a-plot-with-latex-strings/110163)

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**Author:** [@VivMendes](https://discourse.julialang.org/u/VivMendes)\
**Replies:** 3\
**Last updated:** [February 14, 2024, 1:03pm UTC](https://discourse.julialang.org/t/plutoplotly-save-a-plot-with-latex-strings/110163 "2024-02-14T13:03:29Z")

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Hi, I can produce a plot in Pluto with some LaTeX ingredients using PlutoPlotly and LaTexStrings (which is not possible to achieve to the best of my knowledge using PlotlyJS). The plot is perfectly rendered in the noteb…

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## [Multi-threaded code requiring scratch space](https://discourse.julialang.org/t/multi-threaded-code-requiring-scratch-space/109997)

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**Author:** [@PGS62](https://discourse.julialang.org/u/PGS62)\
**Replies:** 17\
**Last updated:** [February 14, 2024, 12:40pm UTC](https://discourse.julialang.org/t/multi-threaded-code-requiring-scratch-space/109997 "2024-02-14T12:40:37Z")

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I think it’s true that to get decent performance from multi-threaded code, it’s a good idea to minimise the amount of allocation done by each task. One way to do this can be calling functions that accept a “scratch” argu…

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## [Comparison of derivative-free / black-box optimization algorithms in Julia](https://discourse.julialang.org/t/comparison-of-derivative-free-black-box-optimization-algorithms-in-julia/109614)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 12\
**Last updated:** [February 14, 2024, 12:02pm UTC](https://discourse.julialang.org/t/comparison-of-derivative-free-black-box-optimization-algorithms-in-julia/109614 "2024-02-14T12:02:11Z")

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Is anyone aware of a comparison between derivative-free / black box optimization libraries in Julia? If not, perhaps it is worth starting one here and finally putting it in the Julia Package Comparisons website? At the …

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## [How to show text only in static Pluto notebook?](https://discourse.julialang.org/t/how-to-show-text-only-in-static-pluto-notebook/110020)

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**Author:** [@pzabka](https://discourse.julialang.org/u/pzabka)\
**Replies:** 3\
**Last updated:** [February 14, 2024, 11:44am UTC](https://discourse.julialang.org/t/how-to-show-text-only-in-static-pluto-notebook/110020 "2024-02-14T11:44:16Z")

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I would like to have a text in a Pluto notebook that would show only if opened in the static version (something like: for interactive version visit website x). Any advice?

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## [Pointer-like field in a struct?](https://discourse.julialang.org/t/pointer-like-field-in-a-struct/109835)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 7\
**Last updated:** [February 14, 2024, 9:56am UTC](https://discourse.julialang.org/t/pointer-like-field-in-a-struct/109835 "2024-02-14T09:56:59Z")

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Hi, I hope somebody here can help me with this one. I’m building a Monte Carlo code for a system of particles. Position coordinates of these N particles are stored in a 3xN array of coordinates r\[:,:\], like for instanc…

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## [Closest cousin of mapview in julia](https://discourse.julialang.org/t/closest-cousin-of-mapview-in-julia/110197)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 1\
**Last updated:** [February 14, 2024, 8:37am UTC](https://discourse.julialang.org/t/closest-cousin-of-mapview-in-julia/110197 "2024-02-14T08:37:41Z")

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The package mapview in R allows one to generate interactive html (with JS) maps, i.e. ones that can be zoomed in and out, moved, shared with others, etcetera. Is there a good alternative in Julia? I’m aware of Leaflet.…

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## [Problem with LSTM and GRU Layers in Flux](https://discourse.julialang.org/t/problem-with-lstm-and-gru-layers-in-flux/110058)

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**Author:** [@LucaGeminiani00](https://discourse.julialang.org/u/LucaGeminiani00)\
**Replies:** 9\
**Last updated:** [February 14, 2024, 8:29am UTC](https://discourse.julialang.org/t/problem-with-lstm-and-gru-layers-in-flux/110058 "2024-02-14T08:29:57Z")

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I have built a Time series forecasting model in Flux.jl including an LSTM layer (the problem is the same also when I include a GRU layer). I am able to train the model without errors. However, when I try to run: model(va…

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## [State of Neuroblox?](https://discourse.julialang.org/t/state-of-neuroblox/110170)

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**Author:** [@benlivingstone](https://discourse.julialang.org/u/benlivingstone)\
**Replies:** 4\
**Last updated:** [February 14, 2024, 6:57am UTC](https://discourse.julialang.org/t/state-of-neuroblox/110170 "2024-02-14T06:57:14Z")

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Hello all, this is my first time posting on Julia Discourse, I hope I’m asking this in the right place. I was just wondering what the state of the Neuroblox package is. I have been looking for a package for modelling ne…

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