# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=351

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**Page:** 352

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## [Non-linear expressions in optimization](https://discourse.julialang.org/t/non-linear-expressions-in-optimization/64969)

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**Author:** [@Daniel\_Villamar](https://discourse.julialang.org/u/Daniel_Villamar)\
**Replies:** 5\
**Last updated:** [July 20, 2021, 4:33pm UTC](https://discourse.julialang.org/t/non-linear-expressions-in-optimization/64969 "2021-07-20T16:33:51Z")

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Hi! I use the version JuMP v0.21.4 and Julia v1.4.2 and I optimizing with Ipopt I ve been working in a non-linear optimization model. Sorry for not presenting a MWE but my code is full of things. I have a problems wit…

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## [PDE heat equation](https://discourse.julialang.org/t/pde-heat-equation/64428)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 24\
**Last updated:** [July 20, 2021, 3:15pm UTC](https://discourse.julialang.org/t/pde-heat-equation/64428 "2021-07-20T15:15:00Z")

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i want to solve the matrix ,but i can’t do it. i am new to Julia. please help me in finding error .i have to plot the last equation given in picture below. what is MethodError i am making?

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## [Empty container reduce error: diff eq](https://discourse.julialang.org/t/empty-container-reduce-error-diff-eq/64956)

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**Author:** [@graham](https://discourse.julialang.org/u/graham)\
**Replies:** 10\
**Last updated:** [July 20, 2021, 2:52pm UTC](https://discourse.julialang.org/t/empty-container-reduce-error-diff-eq/64956 "2021-07-20T14:52:17Z")

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Hi all, I’m trying to use the DifferentialEquations.jl package to perform explicit integration of a mass-spring-damper system. Here are the function I’m solving, and how I passed it into the SecondOrderODEProblem() fun…

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## [Performance issues JuMP, GLPK](https://discourse.julialang.org/t/performance-issues-jump-glpk/64971)

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**Author:** [@Annette\_F](https://discourse.julialang.org/u/Annette_F)\
**Replies:** 4\
**Last updated:** [July 20, 2021, 1:20pm UTC](https://discourse.julialang.org/t/performance-issues-jump-glpk/64971 "2021-07-20T13:20:12Z")

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Goodmorning, I have created the following MIP which I assumed is small and would only take seconds to built and solve. I’ve been working with CPLEX/Gurobi quite a lot, just not in combination with Julia, so I expected …

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## [Fixing parameter values when solving inverse problem using DiffEqFlux](https://discourse.julialang.org/t/fixing-parameter-values-when-solving-inverse-problem-using-diffeqflux/64963)

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**Author:** [@juliascrub](https://discourse.julialang.org/u/juliascrub)\
**Replies:** 1\
**Last updated:** [July 20, 2021, 4:27am UTC](https://discourse.julialang.org/t/fixing-parameter-values-when-solving-inverse-problem-using-diffeqflux/64963 "2021-07-20T04:27:12Z")

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Is there a way to fix certain parameters when using sciml\_train? I could manually override them in the loss function like below but am curious if theres a better way function loss(p) overridden\_p = p but with some p…

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## [Unpredictable learning of neural network based controller for dc motor](https://discourse.julialang.org/t/unpredictable-learning-of-neural-network-based-controller-for-dc-motor/64960)

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**Author:** [@shafeeq\_Elanattil](https://discourse.julialang.org/u/shafeeq_Elanattil)\
**Replies:** 2\
**Last updated:** [July 20, 2021, 4:22am UTC](https://discourse.julialang.org/t/unpredictable-learning-of-neural-network-based-controller-for-dc-motor/64960 "2021-07-20T04:22:14Z")

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Hello, I am new to the Julia language. I am trying to make neural network based position controller using Julia libraries. My code is given below. J = 0.1999 Ke = 2.1918 Kt = 38.185 L = 0.020453 R = 3.9694 Tq = 0.20142…

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## [How do I use Plots with MPIClusterManagers in "only workers" mode?](https://discourse.julialang.org/t/how-do-i-use-plots-with-mpiclustermanagers-in-only-workers-mode/64286)

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**Author:** [@giancarloantonucci](https://discourse.julialang.org/u/giancarloantonucci)\
**Replies:** 2\
**Last updated:** [July 19, 2021, 10:30pm UTC](https://discourse.julialang.org/t/how-do-i-use-plots-with-mpiclustermanagers-in-only-workers-mode/64286 "2021-07-19T22:30:12Z")

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I find that @mpi\_do from MPIClusterManagers.jl is great with Jupiter notebooks. However, I’m not able to plot anything from within @mpi\_do: using MPIClusterManagers using Distributed manager = MPIManager(np = 4) addproc…

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## [ZygoteRules dispatch on traits?](https://discourse.julialang.org/t/zygoterules-dispatch-on-traits/64869)

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**Author:** [@lamorton](https://discourse.julialang.org/u/lamorton)\
**Replies:** 2\
**Last updated:** [July 19, 2021, 5:52pm UTC](https://discourse.julialang.org/t/zygoterules-dispatch-on-traits/64869 "2021-07-19T17:52:05Z")

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Is it possible to specialize a ZygoteRule using a Holy trait? I’m not sure how I would go about doing this.

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## [Cond() error: LinearAlgebra and BigFloats incompatible?](https://discourse.julialang.org/t/cond-error-linearalgebra-and-bigfloats-incompatible/64924)

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**Author:** [@damonturney](https://discourse.julialang.org/u/damonturney)\
**Replies:** 3\
**Last updated:** [July 19, 2021, 5:46pm UTC](https://discourse.julialang.org/t/cond-error-linearalgebra-and-bigfloats-incompatible/64924 "2021-07-19T17:46:57Z")

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In the course of building my simulation of chemicals in an operating battery, I need to invert matrices that are ill-conditioned (condition number near 1E15). My strategy was to use a matrix of BigFloats because they ca…

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## [Running For loops on GPU](https://discourse.julialang.org/t/running-for-loops-on-gpu/1553)

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**Author:** [@deepakagrawal](https://discourse.julialang.org/u/deepakagrawal)\
**Replies:** 11\
**Last updated:** [July 19, 2021, 5:39pm UTC](https://discourse.julialang.org/t/running-for-loops-on-gpu/1553 "2021-07-19T17:39:41Z")

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I am trying to do simulation in which I am repeating same function multiple times Changing several parameters Is there a way I can do any of them via a for loop or some other way on GPU? I am new to Julia. Any help o…

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## [Treemap subplot in PlotlyJS](https://discourse.julialang.org/t/treemap-subplot-in-plotlyjs/64759)

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**Author:** [@stej](https://discourse.julialang.org/u/stej)\
**Replies:** 3\
**Last updated:** [July 19, 2021, 5:18pm UTC](https://discourse.julialang.org/t/treemap-subplot-in-plotlyjs/64759 "2021-07-19T17:18:06Z")

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I wanted to use a treemap in PlotlyJS. There is no method like this, so I create that by hand. fieldsa = Dict{Symbol,Any}(:type =\> "treemap", :labels =\> \["a", "A"\], :parents =\> \["", ""\], :values =\> \[1, 10\], …

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## [Turing.jl - Error running tutorial code](https://discourse.julialang.org/t/turing-jl-error-running-tutorial-code/64867)

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**Author:** [@v-i-s-h](https://discourse.julialang.org/u/v-i-s-h)\
**Replies:** 2\
**Last updated:** [July 19, 2021, 1:23pm UTC](https://discourse.julialang.org/t/turing-jl-error-running-tutorial-code/64867 "2021-07-19T13:23:54Z")

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I was try Turing.jl tutorial code for Bayesian Neural networks (Bayesian Neural Networks) When I try to run the Variational inference code (code below) using Bijectors using Turing: Variational using AdvancedVI m = ba…

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## [Why does \`Flux.stack\` use splatting?](https://discourse.julialang.org/t/why-does-flux-stack-use-splatting/64923)

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**Author:** [@bad\_at\_math](https://discourse.julialang.org/u/bad_at_math)\
**Replies:** 1\
**Last updated:** [July 19, 2021, 1:12pm UTC](https://discourse.julialang.org/t/why-does-flux-stack-use-splatting/64923 "2021-07-19T13:12:49Z")

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The Flux.stack function is defined here: https://github.com/FluxML/Flux.jl/blob/b78a27b01c9629099adb059a98657b995760b617/src/utils.jl#L476, and it is very simple: stack(xs, dim) = cat(unsqueeze.(xs, dim)..., dims=dim). …

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## [Streamplot statemap using JSServe](https://discourse.julialang.org/t/streamplot-statemap-using-jsserve/64337)

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**Author:** [@EvoArt](https://discourse.julialang.org/u/EvoArt)\
**Replies:** 13\
**Last updated:** [July 19, 2021, 10:52am UTC](https://discourse.julialang.org/t/streamplot-statemap-using-jsserve/64337 "2021-07-19T10:52:33Z")

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I’m trying to record a statemap to include an interactive streamplot in a web page. Is there a way to pull out the actual Float64 value from the observable? Thanks in advance. using WGLMakie, JSServe WGLMakie.activate!…

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## [Use the non-missing elements of DataFrame A to update DataFrame B](https://discourse.julialang.org/t/use-the-non-missing-elements-of-dataframe-a-to-update-dataframe-b/64658)

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**Author:** [@fipelle](https://discourse.julialang.org/u/fipelle)\
**Replies:** 9\
**Last updated:** [July 18, 2021, 8:53am UTC](https://discourse.julialang.org/t/use-the-non-missing-elements-of-dataframe-a-to-update-dataframe-b/64658 "2021-07-18T08:53:57Z")

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Hi, I am trying to find an elegant solution to update a DataFrame (B), using the non-missing elements in another DataFrame (A) with the same columns. For instance, with using Dates, DataFrames; # Dates date\_1 = Date("…

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## [How to center a text with Luxor](https://discourse.julialang.org/t/how-to-center-a-text-with-luxor/55125)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 4\
**Last updated:** [July 18, 2021, 8:22am UTC](https://discourse.julialang.org/t/how-to-center-a-text-with-luxor/55125 "2021-07-18T08:22:14Z")

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I am trying to create simple images with a text made of a few digits on the center. The problem is that I need to manually offset the position, is there a way to make it “centered” in a visual sense, i.e. where the spa…

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## [How to make GLFW window non blocking](https://discourse.julialang.org/t/how-to-make-glfw-window-non-blocking/64804)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 1\
**Last updated:** [July 18, 2021, 4:15am UTC](https://discourse.julialang.org/t/how-to-make-glfw-window-non-blocking/64804 "2021-07-18T04:15:57Z")

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Hello I am creating some openGL GUI and I have probably simple to solve problem - I want to have the rendering loop non blocking i.e so for example I will be able to run the openGL app and make it possible to 1) respond…

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## [Need help with loading plots in dash](https://discourse.julialang.org/t/need-help-with-loading-plots-in-dash/64841)

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**Author:** [@Goku](https://discourse.julialang.org/u/Goku)\
**Replies:** 0\
**Last updated:** [July 18, 2021, 1:00am UTC](https://discourse.julialang.org/t/need-help-with-loading-plots-in-dash/64841 "2021-07-18T01:00:25Z")

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I am trying to host this plot in dash, but I am getting the following error: Error loading layout Full Code: using CSV, DataFrames, Dates, Plots using Dash, DashHtmlComponents, DashCoreComponents plotly() df = CSV…

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## [DP5() algorithm failing to solve simple SIR problem?](https://discourse.julialang.org/t/dp5-algorithm-failing-to-solve-simple-sir-problem/64835)

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**Author:** [@Michael\_Barmann](https://discourse.julialang.org/u/Michael_Barmann)\
**Replies:** 1\
**Last updated:** [July 17, 2021, 11:34pm UTC](https://discourse.julialang.org/t/dp5-algorithm-failing-to-solve-simple-sir-problem/64835 "2021-07-17T23:34:05Z")

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While testing out different ODE solvers, I found that DP5() completely fails when given a simple SIR model (while other solvers handle it perfectly fine): function SIR!(du,u,pars,t) β, γ = pars S, I, R = u …

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## [Range constraint](https://discourse.julialang.org/t/range-constraint/64819)

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**Author:** [@mjanun](https://discourse.julialang.org/u/mjanun)\
**Replies:** 10\
**Last updated:** [July 17, 2021, 9:35pm UTC](https://discourse.julialang.org/t/range-constraint/64819 "2021-07-17T21:35:16Z")

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I have a constraint that can be either a range or an equality depending upon whether a user passes a range (i.e. two arguments) or a single value as a constraint. I convert the range constraint to an equality using the s…

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## [Join vs innerjoin and pkg updating](https://discourse.julialang.org/t/join-vs-innerjoin-and-pkg-updating/64778)

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**Author:** [@davidoff](https://discourse.julialang.org/u/davidoff)\
**Replies:** 10\
**Last updated:** [July 17, 2021, 1:30am UTC](https://discourse.julialang.org/t/join-vs-innerjoin-and-pkg-updating/64778 "2021-07-17T01:30:55Z")

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I have the same version of Julia and same Pkg.update() vintage on 2 different computers. On one, when I merge data frames, I use join() and the other innerjoin() – on each of the two computers, the alternative join comma…

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## [Help with Turing.jl model using Categorical, Normal and ordered constraint](https://discourse.julialang.org/t/help-with-turing-jl-model-using-categorical-normal-and-ordered-constraint/64765)

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**Author:** [@Hakan\_Kjellerstrand](https://discourse.julialang.org/u/Hakan_Kjellerstrand)\
**Replies:** 2\
**Last updated:** [July 16, 2021, 9:05pm UTC](https://discourse.julialang.org/t/help-with-turing-jl-model-using-categorical-normal-and-ordered-constraint/64765 "2021-07-16T21:05:06Z")

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I’m trying to model AllenDowney’s three problems “How tall is A?” (How tall is A? – Probably Overthinking It ): 1) Suppose you meet an adult resident of the U.S. who is 170 cm tall. What is the probability that th…

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## [Order of groupedbar](https://discourse.julialang.org/t/order-of-groupedbar/64749)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 1\
**Last updated:** [July 16, 2021, 7:32pm UTC](https://discourse.julialang.org/t/order-of-groupedbar/64749 "2021-07-16T19:32:10Z")

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I have the following plot of a Likert scale: StatsPlots.groupedbar( repeat(questions, outer = 5), weights, group=repeat(\["1", "2", "3", "4", "5"\], inner=length(questions)), bar\_position=:stack, o…

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## [Chi-Square test of a sample](https://discourse.julialang.org/t/chi-square-test-of-a-sample/63617)

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**Author:** [@Mariana](https://discourse.julialang.org/u/Mariana)\
**Replies:** 19\
**Last updated:** [July 16, 2021, 8:50am UTC](https://discourse.julialang.org/t/chi-square-test-of-a-sample/63617 "2021-07-16T08:50:22Z")

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Hello! I am working on a project in which I was given a random sample, and now I want to identify, among 3 distributions, which one created this sample. By plotting a histogram, it seems that the gamma distribution is …

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## [BERT models from huggingface - Transformers.jl](https://discourse.julialang.org/t/bert-models-from-huggingface-transformers-jl/64453)

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**Author:** [@Alex\_Tantos](https://discourse.julialang.org/u/Alex_Tantos)\
**Replies:** 1\
**Last updated:** [July 15, 2021, 10:50pm UTC](https://discourse.julialang.org/t/bert-models-from-huggingface-transformers-jl/64453 "2021-07-15T22:50:32Z")

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Hi! @chengchingwen Am planning to use an already pre-trained BERT model for Greek published in huggingface. As we know for using this type of pre-trained models, one depends on python’s hugginface and pytorch. I know t…

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## [Histogram counts in bin under mouse hover](https://discourse.julialang.org/t/histogram-counts-in-bin-under-mouse-hover/53743)

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**Author:** [@mocalvao](https://discourse.julialang.org/u/mocalvao)\
**Replies:** 0\
**Last updated:** [January 21, 2021, 8:01pm UTC](https://discourse.julialang.org/t/histogram-counts-in-bin-under-mouse-hover/53743 "2021-01-21T20:01:01Z")

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I would like to make a histogram, under IJulia jupyter notebook, such that, when I hover the mouse over the bars, I get the number of ocurrences within the corresponding bins, as a tooltip. My MWE is: using PlotlyJS plo…

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## [Should the repl show images?](https://discourse.julialang.org/t/should-the-repl-show-images/64672)

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**Author:** [@cybervigilante](https://discourse.julialang.org/u/cybervigilante)\
**Replies:** 16\
**Last updated:** [July 15, 2021, 7:14pm UTC](https://discourse.julialang.org/t/should-the-repl-show-images/64672 "2021-07-15T19:14:54Z")

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When I create an image in the repl I get a huge RGB array, but in Jupyterlab I do get the image. I thought the repl also showed images. That is: using Images, TestImages img = testimage(“mandrill”) shows a mandrill in…

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## [Makie - Incorrect isosurface rendering](https://discourse.julialang.org/t/makie-incorrect-isosurface-rendering/64688)

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**Author:** [@tehl](https://discourse.julialang.org/u/tehl)\
**Replies:** 3\
**Last updated:** [July 15, 2021, 4:55pm UTC](https://discourse.julialang.org/t/makie-incorrect-isosurface-rendering/64688 "2021-07-15T16:55:43Z")

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The isosurface example from the Makie docs doesn’t render correctly (see image below). Has anyone come across this problem? Potentially relevant glxinfo: Vendor: AMD (0x1002) Device: AMD Radeon (TM) RX 480 Graphics (PO…

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## [Turing.jl: Warnings when running generated\_quantities](https://discourse.julialang.org/t/turing-jl-warnings-when-running-generated-quantities/64698)

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**Author:** [@Hakan\_Kjellerstrand](https://discourse.julialang.org/u/Hakan_Kjellerstrand)\
**Replies:** 2\
**Last updated:** [July 15, 2021, 3:57pm UTC](https://discourse.julialang.org/t/turing-jl-warnings-when-running-generated-quantities/64698 "2021-07-15T15:57:52Z")

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When calling generated\_quantities there is always a huge number of warnings with the following message Warning: the following keys were not found in \`vi\`, and thus \`kernel!\` was not applied to these: \["lp"\] └ @ DynamicP…

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## [Unable to save and load model (or parameters) with BSON either on GPU or CPU](https://discourse.julialang.org/t/unable-to-save-and-load-model-or-parameters-with-bson-either-on-gpu-or-cpu/64582)

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**Author:** [@sguns](https://discourse.julialang.org/u/sguns)\
**Replies:** 2\
**Last updated:** [July 15, 2021, 2:17am UTC](https://discourse.julialang.org/t/unable-to-save-and-load-model-or-parameters-with-bson-either-on-gpu-or-cpu/64582 "2021-07-15T02:17:50Z")

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Hi, I’m training a model on GPU and trying to save intermediate states to disk as described in the Flux docs. Unfortunately it seems like the information about saving GPU models (in the blue box) is wrong - although I c…

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