# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=405

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**Page:** 406

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## [Workflow for hosting "data" packages with artifacts](https://discourse.julialang.org/t/workflow-for-hosting-data-packages-with-artifacts/50868)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 3\
**Last updated:** [November 27, 2020, 4:47pm UTC](https://discourse.julialang.org/t/workflow-for-hosting-data-packages-with-artifacts/50868 "2020-11-27T16:47:55Z")

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There seems to be broad consensus that using artifacts is the preferred way of hosting data for a package. Say, hypothetically, I were to make a package which makes it easier for users to download datasets from Hayashi’s…

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## [Package/algorithm for barycentric grid interpolation](https://discourse.julialang.org/t/package-algorithm-for-barycentric-grid-interpolation/50803)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 6\
**Last updated:** [November 27, 2020, 3:16pm UTC](https://discourse.julialang.org/t/package-algorithm-for-barycentric-grid-interpolation/50803 "2020-11-27T15:16:35Z")

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I am looking for a package or an algorithm (which I am happy to code into a package and make it available) that expresses a coordinate inside a simplex as a convex combination “near” of points with integer coordinates. F…

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## [Printing Diagnostic Info in Parallel](https://discourse.julialang.org/t/printing-diagnostic-info-in-parallel/47787)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [November 27, 2020, 12:03pm UTC](https://discourse.julialang.org/t/printing-diagnostic-info-in-parallel/47787 "2020-11-27T12:03:20Z")

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If I am using Distributed, is there a way to print diagnostic information from the different workers? I’m thinking of something like this: @everywhere x = rand(); and I would like to be able to print what value of x e…

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## [Reading Parquet file into Apache Arrow?](https://discourse.julialang.org/t/reading-parquet-file-into-apache-arrow/50851)

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**Author:** [@s-kap](https://discourse.julialang.org/u/s-kap)\
**Replies:** 5\
**Last updated:** [November 27, 2020, 11:17am UTC](https://discourse.julialang.org/t/reading-parquet-file-into-apache-arrow/50851 "2020-11-27T11:17:18Z")

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Hey hey, what’s the easiest way to read a parquet file into an apache arrow dataset? In python one can simply do pyarrow.parquet.read\_table(..). I know Parquet.jl and Arrow.jl exist, but I haven’t found a way to make the…

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## [IterativeSolvers and Positive Definite Matrices](https://discourse.julialang.org/t/iterativesolvers-and-positive-definite-matrices/50292)

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**Author:** [@Jonas](https://discourse.julialang.org/u/Jonas)\
**Replies:** 18\
**Last updated:** [November 27, 2020, 9:36am UTC](https://discourse.julialang.org/t/iterativesolvers-and-positive-definite-matrices/50292 "2020-11-27T09:36:24Z")

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Hello dear Julia Users, In order to calculate eigenvalues and vectors I am currently using the package IterativeSolvers, but I often get the error that my input matrices are not positive definite. My code is like this: …

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## [Convert Array{UInt32, 2} to ARGB image with Images.jl](https://discourse.julialang.org/t/convert-array-uint32-2-to-argb-image-with-images-jl/50822)

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**Author:** [@wrgr](https://discourse.julialang.org/u/wrgr)\
**Replies:** 2\
**Last updated:** [November 27, 2020, 7:53am UTC](https://discourse.julialang.org/t/convert-array-uint32-2-to-argb-image-with-images-jl/50822 "2020-11-27T07:53:05Z")

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How to convert Array{UInt32, 2} to ARGB image with Images.jl?

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## [Fft() function does not return the correct analytic result](https://discourse.julialang.org/t/fft-function-does-not-return-the-correct-analytic-result/50644)

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**Author:** [@tiago](https://discourse.julialang.org/u/tiago)\
**Replies:** 5\
**Last updated:** [November 26, 2020, 7:21pm UTC](https://discourse.julialang.org/t/fft-function-does-not-return-the-correct-analytic-result/50644 "2020-11-26T19:21:58Z")

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Hello, currently I’m having issues understanding how to perform with success a Fourier Transformation using the fft() function of the fftw.jl package. Let’s pick the step function: using FFTW, Plots x = range(-5,stop=5…

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## [Using gradients from struct with Zygote](https://discourse.julialang.org/t/using-gradients-from-struct-with-zygote/50766)

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**Author:** [@theogf](https://discourse.julialang.org/u/theogf)\
**Replies:** 2\
**Last updated:** [November 26, 2020, 12:35pm UTC](https://discourse.julialang.org/t/using-gradients-from-struct-with-zygote/50766 "2020-11-26T12:35:15Z")

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Hi! Let’s say I have some nested struct (in my case the nesting is arbitrarily complicated) struct Foo a::Vector end struct Bar b::Foo c::Float64 end c = Bar(Foo(\[2.0\]), 1.0) When using g = Zygote.gradient(c) do x …

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## [Biostructures.jl and md trajectory files](https://discourse.julialang.org/t/biostructures-jl-and-md-trajectory-files/50789)

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**Author:** [@bharland](https://discourse.julialang.org/u/bharland)\
**Replies:** 3\
**Last updated:** [November 26, 2020, 11:59am UTC](https://discourse.julialang.org/t/biostructures-jl-and-md-trajectory-files/50789 "2020-11-26T11:59:01Z")

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I’m wondering how horrendous it would be to include parsing of popular trajectory files, so I had a look at how MDTraj did it with (e.g.) the xtc format. A layer of python, then cython and then a set of c files adapted …

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## [CUDA.jl : Is the Surface Object available?](https://discourse.julialang.org/t/cuda-jl-is-the-surface-object-available/50796)

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**Author:** [@kemu](https://discourse.julialang.org/u/kemu)\
**Replies:** 3\
**Last updated:** [November 26, 2020, 9:26am UTC](https://discourse.julialang.org/t/cuda-jl-is-the-surface-object-available/50796 "2020-11-26T09:26:53Z")

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I’m investigating porting from python/pycuda to julia/CUDA.jl. Pycuda supports Texture / Surface Reference API, so we can read the data with interpolation through a texture reference, and write data through a surface re…

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## [Question about JuMP](https://discourse.julialang.org/t/question-about-jump/50675)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 3\
**Last updated:** [November 26, 2020, 6:52am UTC](https://discourse.julialang.org/t/question-about-jump/50675 "2020-11-26T06:52:42Z")

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there is something wrong with my JuMP! It used to work!why? :persevere: thank you!

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## [How to set x-axis positions in StatPlots' violin plot?](https://discourse.julialang.org/t/how-to-set-x-axis-positions-in-statplots-violin-plot/15421)

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**Author:** [@rickhg12hs](https://discourse.julialang.org/u/rickhg12hs)\
**Replies:** 4\
**Last updated:** [September 24, 2018, 1:00pm UTC](https://discourse.julialang.org/t/how-to-set-x-axis-positions-in-statplots-violin-plot/15421 "2018-09-24T13:00:53Z")

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I’d like to create a violin plot of a DataFrame and set each “violin” at its linear respective position. For example, this plot: # some data to play with n = 10000 f(k) = randn(k) df2 = DataFrame(hcat(f(n).+1, f(n).-1, …

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## [Eigenvalues for lots of small matrices, GPU batched vs CPU eigen](https://discourse.julialang.org/t/eigenvalues-for-lots-of-small-matrices-gpu-batched-vs-cpu-eigen/50792)

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**Author:** [@arxiv](https://discourse.julialang.org/u/arxiv)\
**Replies:** 0\
**Last updated:** [November 26, 2020, 2:48am UTC](https://discourse.julialang.org/t/eigenvalues-for-lots-of-small-matrices-gpu-batched-vs-cpu-eigen/50792 "2020-11-26T02:48:31Z")

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I need to diagonalize lots of small matrices of the same size, like 50000 matrices of size 50x50, and wonder if using GPU to diagonalize them in parallel will help. So I set up a small test: using LinearAlgebra using C…

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## [Sort and collapse a vector with GPU](https://discourse.julialang.org/t/sort-and-collapse-a-vector-with-gpu/50685)

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**Author:** [@Ward9250](https://discourse.julialang.org/u/Ward9250)\
**Replies:** 3\
**Last updated:** [November 26, 2020, 2:36am UTC](https://discourse.julialang.org/t/sort-and-collapse-a-vector-with-gpu/50685 "2020-11-26T02:36:08Z")

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As my first attempt at something serious and practical I want to achieve with a GPU, I have a problem where I have an array of elements, each element is a tuple of (value, count\_of\_value). count\_of\_value is initially uni…

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## [How to implement a \`nop()\` loop for sub-µs delays? (Raspberry Pi, GPIO)](https://discourse.julialang.org/t/how-to-implement-a-nop-loop-for-sub-s-delays-raspberry-pi-gpio/50790)

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**Author:** [@notinaboat](https://discourse.julialang.org/u/notinaboat)\
**Replies:** 0\
**Last updated:** [November 26, 2020, 1:46am UTC](https://discourse.julialang.org/t/how-to-implement-a-nop-loop-for-sub-s-delays-raspberry-pi-gpio/50790 "2020-11-26T01:46:30Z")

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Hello Julia people, I’ve enjoyed using Julia for signal processing and numeric work and I’ve also tried it for some scripting and automation tasks (with mixed results, sometimes the start-up delay is a killer). I am cu…

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## [MLJ needs your testimony](https://discourse.julialang.org/t/mlj-needs-your-testimony/50784)

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**Author:** [@TheRoniOne](https://discourse.julialang.org/u/TheRoniOne)\
**Replies:** 0\
**Last updated:** [November 25, 2020, 11:54pm UTC](https://discourse.julialang.org/t/mlj-needs-your-testimony/50784 "2020-11-25T23:54:25Z")

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In The Alan Turing Institute they are reviewing the funding of MLJ and they are asking for evidence that MLJ is being used, filling a need and having an impact. In order for the project to continue seeing support, they n…

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## [Blank GLMakie.jl window make system unusable while open](https://discourse.julialang.org/t/blank-glmakie-jl-window-make-system-unusable-while-open/50763)

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**Author:** [@ndinsmore](https://discourse.julialang.org/u/ndinsmore)\
**Replies:** 3\
**Last updated:** [November 25, 2020, 8:51pm UTC](https://discourse.julialang.org/t/blank-glmakie-jl-window-make-system-unusable-while-open/50763 "2020-11-25T20:51:38Z")

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Whenever I make something simple as even a large blank Makie window my system becomes unusable. For example, if I switch back to vs code it takes a good 3-4 seconds for the text to show up in the editor window, and the…

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## [Using Query.jl with an array of Dict](https://discourse.julialang.org/t/using-query-jl-with-an-array-of-dict/50770)

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**Author:** [@Peter\_Staab](https://discourse.julialang.org/u/Peter_Staab)\
**Replies:** 1\
**Last updated:** [November 25, 2020, 7:56pm UTC](https://discourse.julialang.org/t/using-query-jl-with-an-array-of-dict/50770 "2020-11-25T19:56:29Z")

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I have an array of Dicts (from JSON.jl), which I am trying to perform query commands. Here’s a shorter example though: test = \[Dict("a"=\>1,"b"=\>1),Dict("a"=\>1,"b"=\>2),Dict("a"=\>2,"b"=\>3)\] test |\> @map({\_\["a"\],\_\["b"\]}) …

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## [Sample from Kernel Density Estimator](https://discourse.julialang.org/t/sample-from-kernel-density-estimator/50639)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 3\
**Last updated:** [November 25, 2020, 3:59pm UTC](https://discourse.julialang.org/t/sample-from-kernel-density-estimator/50639 "2020-11-25T15:59:04Z")

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From a sample of data I can create a KDE to estimate the probability density with KernelDensity.jl, e.g.: density\_estimator = kde(data) Now, is there any package or custom code that I could use to retrieve a sample fro…

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## [Pkg test CUDA on Windows 10, Julia 1.5.2](https://discourse.julialang.org/t/pkg-test-cuda-on-windows-10-julia-1-5-2/49209)

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**Author:** [@arxiv](https://discourse.julialang.org/u/arxiv)\
**Replies:** 2\
**Last updated:** [November 25, 2020, 12:32pm UTC](https://discourse.julialang.org/t/pkg-test-cuda-on-windows-10-julia-1-5-2/49209 "2020-11-25T12:32:12Z")

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I just added CUDA.jl and ran Pkg test, did not pass. Wonder what the issue is. Machine info: Windows 10, GeForce MX150 Julia version info: Julia Version 1.5.2 Commit 539f3ce943 (2020-09-23 23:17 UTC) Platform Info: …

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## [DataFrame conversion of column names to type](https://discourse.julialang.org/t/dataframe-conversion-of-column-names-to-type/50694)

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**Author:** [@optimist](https://discourse.julialang.org/u/optimist)\
**Replies:** 5\
**Last updated:** [November 25, 2020, 11:05am UTC](https://discourse.julialang.org/t/dataframe-conversion-of-column-names-to-type/50694 "2020-11-25T11:05:46Z")

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I use DataFrames to read a CSV file. I need to determine the number of columns with the header dates (e.g. 01/10/2020) and extract those column names and convert their type to Date. In my MWE, I have shown two methods t…

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## [Pass optional parameters to model in DifferentialEquations.jl](https://discourse.julialang.org/t/pass-optional-parameters-to-model-in-differentialequations-jl/50718)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 2\
**Last updated:** [November 25, 2020, 8:59am UTC](https://discourse.julialang.org/t/pass-optional-parameters-to-model-in-differentialequations-jl/50718 "2020-11-25T08:59:51Z")

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Hello, I would like to pass optional arguments to a DifferentialEquations.jl ODE model at ODEProblem time. Those optional arguments are meant to alter the model without using the p argument which I would like to save fo…

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## [Saving functions with JLD2](https://discourse.julialang.org/t/saving-functions-with-jld2/50717)

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**Author:** [@SamBrand](https://discourse.julialang.org/u/SamBrand)\
**Replies:** 2\
**Last updated:** [November 25, 2020, 8:01am UTC](https://discourse.julialang.org/t/saving-functions-with-jld2/50717 "2020-11-25T08:01:43Z")

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Hi all, I am currently engaged in modelling/forecasting SARS-CoV-2 transmission (like everyone else it feels like…). My current work flow involves parameter inference, and I contain all the relevant information about w…

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## [Unable to retrieve solution after solving JuMP model](https://discourse.julialang.org/t/unable-to-retrieve-solution-after-solving-jump-model/50720)

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**Author:** [@trathi](https://discourse.julialang.org/u/trathi)\
**Replies:** 2\
**Last updated:** [November 25, 2020, 1:41am UTC](https://discourse.julialang.org/t/unable-to-retrieve-solution-after-solving-jump-model/50720 "2020-11-25T01:41:58Z")

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I have a large code that solves an optimization model. To keep the code clean I am trying to move the part that calls the optimizer and retrieve solution to a separate function. Even though I am able to solve the model t…

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## [JuMP: Register arbitary number of functions and use as constraints](https://discourse.julialang.org/t/jump-register-arbitary-number-of-functions-and-use-as-constraints/19692)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 7\
**Last updated:** [November 24, 2020, 10:01pm UTC](https://discourse.julialang.org/t/jump-register-arbitary-number-of-functions-and-use-as-constraints/19692 "2020-11-24T22:01:29Z")

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I am doing some optimisation, the problems all look the same but the number of variables differ. I am trying to create a function which will do the optimisation problem in one line (optimise\_this(some\_problem)). The prob…

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## [Approximating A+B\*log with NeuralNetwork](https://discourse.julialang.org/t/approximating-a-b-log-with-neuralnetwork/50709)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 0\
**Last updated:** [November 24, 2020, 7:57pm UTC](https://discourse.julialang.org/t/approximating-a-b-log-with-neuralnetwork/50709 "2020-11-24T19:57:22Z")

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Dear All, I am working on an economics project which utilizes neural networks as a method for approximation of model solutions (those models are systems of differential/difference equations). For some versions of these …

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## [oneAPI.jl @sync bug?](https://discourse.julialang.org/t/oneapi-jl-sync-bug/50696)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 3\
**Last updated:** [November 24, 2020, 4:38pm UTC](https://discourse.julialang.org/t/oneapi-jl-sync-bug/50696 "2020-11-24T16:38:48Z")

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Hi, I am trying the oneAPI.jl package and I have an issue with timing: The following MWE gives me incredible speed-ups and I guess that oneAPI.@sync may not work properly… using oneAPI using BenchmarkTools n=2^25 on…

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## [Abc\_inference with parallel = true gives error in DifferentialEquations.jl](https://discourse.julialang.org/t/abc-inference-with-parallel-true-gives-error-in-differentialequations-jl/50681)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 2\
**Last updated:** [November 24, 2020, 3:56pm UTC](https://discourse.julialang.org/t/abc-inference-with-parallel-true-gives-error-in-differentialequations-jl/50681 "2020-11-24T15:56:59Z")

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Hello, I get a strange error when setting parallel = true in abc\_inference. So I start by opening a julia REPL, enable julia to use multiple cores and launch jupyterlab: |julia\> ENV\["JULIA\_NUM\_THREADS"\] = 5 5 |julia\> …

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## [Fun Animations](https://discourse.julialang.org/t/fun-animations/45542)

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**Author:** [@anon92994695](https://discourse.julialang.org/u/anon92994695)\
**Replies:** 8\
**Last updated:** [November 24, 2020, 2:34pm UTC](https://discourse.julialang.org/t/fun-animations/45542 "2020-11-24T14:34:20Z")

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Figured I’d try out another weird thread idea. The idea is: if you have a fun animation share it below. Discussions about animations welcome, but being a jerk is not. Doesn’t need to be cream of the crop highly polished,…

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## [Error: JuMP model variable not defined](https://discourse.julialang.org/t/error-jump-model-variable-not-defined/50670)

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**Author:** [@trathi](https://discourse.julialang.org/u/trathi)\
**Replies:** 5\
**Last updated:** [November 24, 2020, 12:22pm UTC](https://discourse.julialang.org/t/error-jump-model-variable-not-defined/50670 "2020-11-24T12:22:24Z")

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I am trying to use the package Dualization.jl, to reformulate a primal problem and solving the dual model separately. However, after solving I am not able to access the solution (the variable values) as they don’t seem t…

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