# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=469

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**Page:** 470

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## [Solves the linear system using CuArrays.jl](https://discourse.julialang.org/t/solves-the-linear-system-using-cuarrays-jl/32692)

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**Author:** [@FujiwaraTakumiEH](https://discourse.julialang.org/u/FujiwaraTakumiEH)\
**Replies:** 3\
**Last updated:** [December 27, 2019, 1:18pm UTC](https://discourse.julialang.org/t/solves-the-linear-system-using-cuarrays-jl/32692 "2019-12-27T13:18:58Z")

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I am new to GPU parallel computing. With my knowledge of CUSOLVER and CUSPARSE, I am sure that I can complete my task through them: Solving large linear sparse equations in parallel. I have read the documentation of CUD…

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## [Advice for simple (mildly large) Turing model](https://discourse.julialang.org/t/advice-for-simple-mildly-large-turing-model/32719)

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**Author:** [@opera\_malenky](https://discourse.julialang.org/u/opera_malenky)\
**Replies:** 9\
**Last updated:** [December 26, 2019, 10:00pm UTC](https://discourse.julialang.org/t/advice-for-simple-mildly-large-turing-model/32719 "2019-12-26T22:00:13Z")

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I have a simple Turing model I’ve been trying to implement, but I’ve been running into problems actually running it. I say simple, but my actual problem is not “small”, parameter-wise. I have about 18 groups, with about …

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## [Simplify MINLP problem to speed up results](https://discourse.julialang.org/t/simplify-minlp-problem-to-speed-up-results/32522)

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**Author:** [@Hector\_Esteban](https://discourse.julialang.org/u/Hector_Esteban)\
**Replies:** 5\
**Last updated:** [December 26, 2019, 6:41pm UTC](https://discourse.julialang.org/t/simplify-minlp-problem-to-speed-up-results/32522 "2019-12-26T18:41:31Z")

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Hey people, I want to optimize the path of a vehicle consisting on an array/vector of states of the form \[x\_i,y\_i,theta\_i\] and my control inputs are \[kappa\_i,dS\_i\]. As I am dealing with a MINLP problem (MI because I per…

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## [Libopenspecfun.dll could not be found error](https://discourse.julialang.org/t/libopenspecfun-dll-could-not-be-found-error/32649)

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**Author:** [@Xentios](https://discourse.julialang.org/u/Xentios)\
**Replies:** 3\
**Last updated:** [December 26, 2019, 6:38pm UTC](https://discourse.julialang.org/t/libopenspecfun-dll-could-not-be-found-error/32649 "2019-12-26T18:38:03Z")

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ERROR: LoadError: InitError: could not load library “C:\\Users\\Xentios.julia\\artifacts\\e062344a002c2afdfcf57091b975e56fd80de418\\bin\\libopenspecfun.dll” The specified module could not be found. I am using Gurobi with JuM…

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## [VegaLite.jl; what needs doing?](https://discourse.julialang.org/t/vegalite-jl-what-needs-doing/31940)

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**Author:** [@Usor](https://discourse.julialang.org/u/Usor)\
**Replies:** 12\
**Last updated:** [December 26, 2019, 1:24pm UTC](https://discourse.julialang.org/t/vegalite-jl-what-needs-doing/31940 "2019-12-26T13:24:50Z")

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I do not consider myself great at VegaLite.jl and I don’t know all its elements. I am still getting used to it more and more and don’t always have much time. Still I am interested in possibly helping with this project. I…

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## [Plotting differential equation solutions](https://discourse.julialang.org/t/plotting-differential-equation-solutions/32705)

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**Author:** [@yuxi.liu](https://discourse.julialang.org/u/yuxi.liu)\
**Replies:** 1\
**Last updated:** [December 26, 2019, 12:29pm UTC](https://discourse.julialang.org/t/plotting-differential-equation-solutions/32705 "2019-12-26T12:29:21Z")

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The following code runs really slowly, because it redraws the graph every update, instead of incrementally. There must be some method for incremental diagramming, but I can’t find any. There should be a way to plot this…

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## [Error Symbolic calculations could not initiate. Likely there's a function which is not differentiable by SymEngine](https://discourse.julialang.org/t/error-symbolic-calculations-could-not-initiate-likely-theres-a-function-which-is-not-differentiable-by-symengine/32707)

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**Author:** [@yuxi.liu](https://discourse.julialang.org/u/yuxi.liu)\
**Replies:** 1\
**Last updated:** [December 26, 2019, 12:28pm UTC](https://discourse.julialang.org/t/error-symbolic-calculations-could-not-initiate-likely-theres-a-function-which-is-not-differentiable-by-symengine/32707 "2019-12-26T12:28:37Z")

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I’m simulating a satellite around the earth, and got error: Symbolic calculations could not initiate. Likely there's a function which is not differentiable by SymEngine. I think it’s because it cannot differentiate the…

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## [Plotting vector fields](https://discourse.julialang.org/t/plotting-vector-fields/32704)

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**Author:** [@yuxi.liu](https://discourse.julialang.org/u/yuxi.liu)\
**Replies:** 5\
**Last updated:** [December 26, 2019, 8:27am UTC](https://discourse.julialang.org/t/plotting-vector-fields/32704 "2019-12-26T08:27:03Z")

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I wrote this down because it is weirdly hard to find anything on this topic. To plot vector fields, use the undocumented (as of 2019 Dec 26) quiver function. Quiver is a strange name, coming from the military: a “quiver…

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## [Failed to load \`CUDAdrv\`](https://discourse.julialang.org/t/failed-to-load-cudadrv/32524)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 3\
**Last updated:** [December 26, 2019, 1:02am UTC](https://discourse.julialang.org/t/failed-to-load-cudadrv/32524 "2019-12-26T01:02:22Z")

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I am, for the first time, trying to learn how GPU programming works. I have two Tesla K80s on a HPC. To begin I request the proper node through slurm, and launch an interactive job. \[affans@hpc ~\]$ srun -p gpuq --gres=g…

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## [VegaLite.jl; sorting problematic](https://discourse.julialang.org/t/vegalite-jl-sorting-problematic/31939)

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**Author:** [@Usor](https://discourse.julialang.org/u/Usor)\
**Replies:** 4\
**Last updated:** [December 25, 2019, 8:47pm UTC](https://discourse.julialang.org/t/vegalite-jl-sorting-problematic/31939 "2019-12-25T20:47:51Z")

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I looked on the site to translate some things to see hoe and if it worked: Sorting | Vega-Lite If I want to use for some channel (y) the x channel, then taking their example doesn’t work and gives no result, unless I us…

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## [SplitApplyCombine.jl \`group\` enhancements, reaches version 1.0.0](https://discourse.julialang.org/t/splitapplycombine-jl-group-enhancements-reaches-version-1-0-0/32675)

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**Author:** [@andyferris](https://discourse.julialang.org/u/andyferris)\
**Replies:** 1\
**Last updated:** [December 25, 2019, 3:13am UTC](https://discourse.julialang.org/t/splitapplycombine-jl-group-enhancements-reaches-version-1-0-0/32675 "2019-12-25T03:13:07Z")

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Merry Chirstmas everybody, Today I have released version 1.0.0 of SplitApplyCombine.jl, with the headline feature being that grouping functions have moved to returning a dictionary from Dictionaries.jl. On a personal n…

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## [Issue with BNN example from Turing Tutorial](https://discourse.julialang.org/t/issue-with-bnn-example-from-turing-tutorial/32665)

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**Author:** [@nucklass](https://discourse.julialang.org/u/nucklass)\
**Replies:** 3\
**Last updated:** [December 24, 2019, 7:53pm UTC](https://discourse.julialang.org/t/issue-with-bnn-example-from-turing-tutorial/32665 "2019-12-24T19:53:32Z")

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Hi, student and first time poster here. I’ve been trying to work through the tutorials from the Turing documentation, and can’t seem to get the Bayesian Neural Network to run. More specifically, it seems to stem from th…

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## [Empty sums in expressions](https://discourse.julialang.org/t/empty-sums-in-expressions/32454)

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**Author:** [@waumpel](https://discourse.julialang.org/u/waumpel)\
**Replies:** 2\
**Last updated:** [December 20, 2019, 8:00pm UTC](https://discourse.julialang.org/t/empty-sums-in-expressions/32454 "2019-12-20T20:00:36Z")

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When you create an expression that is an empty sum, it evaluates to Val{false}() instead of 0: model = Model() @expression(model, sum(1 for i in 1:0)) julia\> Val{false}() A similar problem was posted in the GitHub issu…

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## [Different loss with Zygote when taking gradients vs. without](https://discourse.julialang.org/t/different-loss-with-zygote-when-taking-gradients-vs-without/32523)

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**Author:** [@holylorenzo](https://discourse.julialang.org/u/holylorenzo)\
**Replies:** 0\
**Last updated:** [December 20, 2019, 6:13pm UTC](https://discourse.julialang.org/t/different-loss-with-zygote-when-taking-gradients-vs-without/32523 "2019-12-20T18:13:06Z")

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I am working on the newest Flux branch and noticed some weird behavior. When I calculate the loss of my model’s outputs I get the following number: \> y\_pred = model(x) \> loss(y\_pred, y) 0.003791215f0 However, doing th…

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## [Quick question on colors in a contour plot](https://discourse.julialang.org/t/quick-question-on-colors-in-a-contour-plot/32493)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 4\
**Last updated:** [December 20, 2019, 2:09pm UTC](https://discourse.julialang.org/t/quick-question-on-colors-in-a-contour-plot/32493 "2019-12-20T14:09:13Z")

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Hi, I’m making a contour plot using something like using Plots p1 = plot(xoffsets, zerrs, out, st=:contour, levels=0.0:0.05:1.00) The plot works but I want to change the color series (the default colors for values nea…

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## [Composite types array, and composite type with array fields](https://discourse.julialang.org/t/composite-types-array-and-composite-type-with-array-fields/32466)

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**Author:** [@garychow](https://discourse.julialang.org/u/garychow)\
**Replies:** 5\
**Last updated:** [December 20, 2019, 3:43am UTC](https://discourse.julialang.org/t/composite-types-array-and-composite-type-with-array-fields/32466 "2019-12-20T03:43:18Z")

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Hi, I am using CUDAnative now and wonder if anyone could point me to a correct direction such that these operations is possible. Is there anyone else found that it will be easier if these 2 functions are supported? I un…

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## [Distributions.jl is there a deterministic distribution?](https://discourse.julialang.org/t/distributions-jl-is-there-a-deterministic-distribution/32475)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 4\
**Last updated:** [December 19, 2019, 1:18pm UTC](https://discourse.julialang.org/t/distributions-jl-is-there-a-deterministic-distribution/32475 "2019-12-19T13:18:37Z")

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I’m working with a structure that has a Distribution field. However I would like it to be able to also take a fixed value without the need to make a Union{Distribution,Real} field type. I think the Dirac distribution doe…

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## [Which package do you find the best for Object detection?](https://discourse.julialang.org/t/which-package-do-you-find-the-best-for-object-detection/32438)

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**Author:** [@alirezamecheng](https://discourse.julialang.org/u/alirezamecheng)\
**Replies:** 1\
**Last updated:** [December 19, 2019, 1:06pm UTC](https://discourse.julialang.org/t/which-package-do-you-find-the-best-for-object-detection/32438 "2019-12-19T13:06:29Z")

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Hello, I’m new to machine learning especially to the subject of Object Detection. If you don’t mind can you please share your experience with me and name a good package to start with? I’m really confused about the diffe…

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## [\[Example\] Use automatic differentiation to find Lagrange multiplier](https://discourse.julialang.org/t/example-use-automatic-differentiation-to-find-lagrange-multiplier/32476)

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**Author:** [@timueh](https://discourse.julialang.org/u/timueh)\
**Replies:** 2\
**Last updated:** [December 19, 2019, 12:11pm UTC](https://discourse.julialang.org/t/example-use-automatic-differentiation-to-find-lagrange-multiplier/32476 "2019-12-19T12:11:25Z")

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Hi there, this post is about a toy example that explores whether and how automatic differentiation (AD) can be used to determine Lagrange multipliers. Setup Take the following toy problem f(\\varepsilon) = \\underset{x\_…

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## [A Julia-compatible alternative to zarr](https://discourse.julialang.org/t/a-julia-compatible-alternative-to-zarr/11842)

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**Author:** [@fabiangans](https://discourse.julialang.org/u/fabiangans)\
**Replies:** 19\
**Last updated:** [December 18, 2019, 8:17pm UTC](https://discourse.julialang.org/t/a-julia-compatible-alternative-to-zarr/11842 "2019-12-18T20:17:12Z")

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Dear Julia community, we are looking for a object-storage compatible file format for quite large dense N-dimensional arrays. Our project partners suggested this Zarr — zarr 2.13.6 documentation format, but there seems t…

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## [User-defined functions with large vector inputs](https://discourse.julialang.org/t/user-defined-functions-with-large-vector-inputs/32434)

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**Author:** [@edljk](https://discourse.julialang.org/u/edljk)\
**Replies:** 4\
**Last updated:** [December 18, 2019, 3:40pm UTC](https://discourse.julialang.org/t/user-defined-functions-with-large-vector-inputs/32434 "2019-12-18T15:40:39Z")

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JuMP documentation suggest to use splatting for user-defined functions with vector inputs. For medium size data this works pretty well but for large scale vectors I encounter a memory issue: julia\> f(x...) = sum(x\[i\] fo…

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## [Some help with ArrayFire + DifferentialEquations](https://discourse.julialang.org/t/some-help-with-arrayfire-differentialequations/32342)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 20\
**Last updated:** [December 18, 2019, 1:50pm UTC](https://discourse.julialang.org/t/some-help-with-arrayfire-differentialequations/32342 "2019-12-18T13:50:47Z")

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Hellos, I noticed that with one line definition for ArrayFire.jl I can make it run together with DifferentialEquations.jl, but it is not working as expected. DifferentialEquations is calling a generic multiplication fu…

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## [KNITRO 'option\_file' is not working](https://discourse.julialang.org/t/knitro-option-file-is-not-working/32410)

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**Author:** [@SingingKim](https://discourse.julialang.org/u/SingingKim)\
**Replies:** 3\
**Last updated:** [December 18, 2019, 8:32am UTC](https://discourse.julialang.org/t/knitro-option-file-is-not-working/32410 "2019-12-18T08:32:24Z")

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Hi all, I’m trying to pass an option file to KNITRO solver and it gives me the following error: using JuMP, KNITRO m = Model(with\_optimizer(KNITRO.Optimizer, option\_file="knitro.opt")) ERROR: MathOptInterface.Unsuppor…

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## [The same network performs differently in Flux.jl and tensorflow](https://discourse.julialang.org/t/the-same-network-performs-differently-in-flux-jl-and-tensorflow/28378)

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**Author:** [@zhangqian](https://discourse.julialang.org/u/zhangqian)\
**Replies:** 13\
**Last updated:** [December 18, 2019, 8:12am UTC](https://discourse.julialang.org/t/the-same-network-performs-differently-in-flux-jl-and-tensorflow/28378 "2019-12-18T08:12:46Z")

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Hi, I am writing a toy model to test the performance of Flux.jl. I generated some dummy data with the following code import numpy as np traindata=np.random.random((10000,50)) target=np.random.random(10000) np.savetxt…

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## [Is it possible to format axis labels as a currency in Plots.jl](https://discourse.julialang.org/t/is-it-possible-to-format-axis-labels-as-a-currency-in-plots-jl/32408)

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**Author:** [@atteson](https://discourse.julialang.org/u/atteson)\
**Replies:** 1\
**Last updated:** [December 17, 2019, 9:42pm UTC](https://discourse.julialang.org/t/is-it-possible-to-format-axis-labels-as-a-currency-in-plots-jl/32408 "2019-12-17T21:42:26Z")

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I saw an online discussion of formatters from 2016 but didn’t see anything in the package.

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## [When are round brackets required for VegaLite?](https://discourse.julialang.org/t/when-are-round-brackets-required-for-vegalite/32401)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 3\
**Last updated:** [December 17, 2019, 8:07pm UTC](https://discourse.julialang.org/t/when-are-round-brackets-required-for-vegalite/32401 "2019-12-17T20:07:23Z")

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In this example, why are the brackets ( and ) needed to surround the extra @vlplot commands? using VegaDatasets dataset("weather.csv") |\> @vlplot(repeat={column=\[:temp\_max,:precipitation,:wind\]}) + ( @vlplot() + …

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## [Plotlyjs.jl - generate composite figure with violin and scatter](https://discourse.julialang.org/t/plotlyjs-jl-generate-composite-figure-with-violin-and-scatter/32402)

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**Author:** [@josephmarturano](https://discourse.julialang.org/u/josephmarturano)\
**Replies:** 0\
**Last updated:** [December 17, 2019, 7:41pm UTC](https://discourse.julialang.org/t/plotlyjs-jl-generate-composite-figure-with-violin-and-scatter/32402 "2019-12-17T19:41:22Z")

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I would like to use PlotlyJS.jl to generate a composite figure with a violin and scatterplot, where the scatterplot is overlayed on top of the violin and is actually the mean ± 95% confidence interval of the mean. My cur…

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## [VegaLite throws error on faceting plots](https://discourse.julialang.org/t/vegalite-throws-error-on-faceting-plots/32396)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 2\
**Last updated:** [December 17, 2019, 7:30pm UTC](https://discourse.julialang.org/t/vegalite-throws-error-on-faceting-plots/32396 "2019-12-17T19:30:02Z")

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The following code plots data on a single plot. The data is melted data with column names Symbol\[:variable, :value, :time\]. I particularly want lines and points for each dataset… I know I can used filled=true but I am a…

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## [ModelingToolkit: variables in an expression and expression simplification](https://discourse.julialang.org/t/modelingtoolkit-variables-in-an-expression-and-expression-simplification/31894)

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**Author:** [@cvanaret](https://discourse.julialang.org/u/cvanaret)\
**Replies:** 6\
**Last updated:** [December 17, 2019, 12:26pm UTC](https://discourse.julialang.org/t/modelingtoolkit-variables-in-an-expression-and-expression-simplification/31894 "2019-12-17T12:26:43Z")

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Hi, I have two questions about the ModelingToolkit package: is there a function that determines the list of variables that occur in an expression? Example: x^2 + y - exp(y) contains x and y is there a function th…

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## [Make an animation fade](https://discourse.julialang.org/t/make-an-animation-fade/32192)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 3\
**Last updated:** [December 16, 2019, 4:30pm UTC](https://discourse.julialang.org/t/make-an-animation-fade/32192 "2019-12-16T16:30:22Z")

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I have managed to create an animation object, either through: anim\_ode = animate(ode\_sol\_1,kwargs...) #using a solution of a differential equation. anim\_macro = @animate for t\_end in 0.:45 plot(0.:0.1:t\_end,t-\>(sin(…

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