# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1270

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

**Page:** 1271

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## [Gtk.jl clear canvas on key event](https://discourse.julialang.org/t/gtk-jl-clear-canvas-on-key-event/67757)

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**Author:** [@htmj](https://discourse.julialang.org/u/htmj)\
**Replies:** 2\
**Last updated:** [September 10, 2021, 2:18pm UTC](https://discourse.julialang.org/t/gtk-jl-clear-canvas-on-key-event/67757 "2021-09-10T14:18:48Z")

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Hi! I’m trying to make a simple drawing app, and i want to clear the canvas when space is pressed. I understood from this discussion Resetting the canvas within Cairo.jl and Gtk.jl for an image selection viewing gui that…

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## [Save Random Forest Model for Use in Android Application](https://discourse.julialang.org/t/save-random-forest-model-for-use-in-android-application/32400)

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**Author:** [@casstrong](https://discourse.julialang.org/u/casstrong)\
**Replies:** 0\
**Last updated:** [December 17, 2019, 7:31pm UTC](https://discourse.julialang.org/t/save-random-forest-model-for-use-in-android-application/32400 "2019-12-17T19:31:19Z")

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I would like to train a random forest classifier (using DecisionTree.jl) and then export it for use in an Android application that I’m developing. I’ve seen ways to save the model as a .jld or a .jld2 file; however, I ha…

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## [Plot Issues: SystemError](https://discourse.julialang.org/t/plot-issues-systemerror/67966)

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**Author:** [@Xiao\_Ran](https://discourse.julialang.org/u/Xiao_Ran)\
**Replies:** 2\
**Last updated:** [September 10, 2021, 1:34pm UTC](https://discourse.julialang.org/t/plot-issues-systemerror/67966 "2021-09-10T13:34:06Z")

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Does anybody know how to solve this? It bothers me for a long time.

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## [Understanding plot recipes with identical arguments](https://discourse.julialang.org/t/understanding-plot-recipes-with-identical-arguments/67921)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 1\
**Last updated:** [September 10, 2021, 1:23pm UTC](https://discourse.julialang.org/t/understanding-plot-recipes-with-identical-arguments/67921 "2021-09-10T13:23:44Z")

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I just discovered the recipes mechanism in order to avoid having Plots as a package dependency. I currently have a plot1(x::TypeX,y::TypeY) and plot2(x::TypeX,y::TypeY) functions which help present the same data in a di…

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## [HTTP.request](https://discourse.julialang.org/t/http-request/67981)

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**Author:** [@Laco\_Kovac](https://discourse.julialang.org/u/Laco_Kovac)\
**Replies:** 1\
**Last updated:** [September 10, 2021, 1:13pm UTC](https://discourse.julialang.org/t/http-request/67981 "2021-09-10T13:13:11Z")

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I found very strange behaviour of HTTP.request call. My code looks like this: try result = HTTP.request(method, url, headers, body) catch e something end Server returns error, status 501 in my case, but it cou…

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## [Finding the coefficient in an expression in Symbolics.jl](https://discourse.julialang.org/t/finding-the-coefficient-in-an-expression-in-symbolics-jl/67424)

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**Author:** [@fgerick](https://discourse.julialang.org/u/fgerick)\
**Replies:** 2\
**Last updated:** [September 10, 2021, 12:44pm UTC](https://discourse.julialang.org/t/finding-the-coefficient-in-an-expression-in-symbolics-jl/67424 "2021-09-10T12:44:59Z")

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Is there already something like the coeff function of SymPy for Symbolics.jl? E.g. in SymPy I do using SymPy @syms x y f() ex = x^2\*diff(f(x,y),y) + y^2 ex.coeff(diff(f(x,y),y)) # x^2 Can I do the same using Symbolics/…

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## [Efficient recursive tuple construction](https://discourse.julialang.org/t/efficient-recursive-tuple-construction/67874)

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**Author:** [@markmbaum](https://discourse.julialang.org/u/markmbaum)\
**Replies:** 19\
**Last updated:** [September 10, 2021, 12:03pm UTC](https://discourse.julialang.org/t/efficient-recursive-tuple-construction/67874 "2021-09-10T12:03:28Z")

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I’m wondering if there is an efficient way to build a tuple recursively. I’m working with a three-term recurrence relationship (specifically, this one). The first and second terms are known. From them, all the other ter…

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## [Lyapunov spectrum for a user-defined dynamical system](https://discourse.julialang.org/t/lyapunov-spectrum-for-a-user-defined-dynamical-system/34208)

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**Author:** [@AhmedAlreweny](https://discourse.julialang.org/u/AhmedAlreweny)\
**Replies:** 2\
**Last updated:** [September 10, 2021, 9:54am UTC](https://discourse.julialang.org/t/lyapunov-spectrum-for-a-user-defined-dynamical-system/34208 "2021-09-10T09:54:25Z")

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Hello, I have seen the nice documentation here about calculating the Lyapunov spectrum for a dynamical system defined in DynamicalSystems.jl . I have a dynamical system (which is a discretized PDE) which I time-integr…

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## [SciML / DiffEqFlux.jl example not working for me](https://discourse.julialang.org/t/sciml-diffeqflux-jl-example-not-working-for-me/67512)

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**Author:** [@mgp](https://discourse.julialang.org/u/mgp)\
**Replies:** 3\
**Last updated:** [September 10, 2021, 9:52am UTC](https://discourse.julialang.org/t/sciml-diffeqflux-jl-example-not-working-for-me/67512 "2021-09-10T09:52:45Z")

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Sorry if this isn’t the right place to ask … I’ve copied and pasted the example code from https://github.com/SciML/DiffEqFlux.jl/blob/master/docs/src/examples/multiple\_shooting.md and I get an error on the line res\_ms =…

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## [Upgrade all environments](https://discourse.julialang.org/t/upgrade-all-environments/67903)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 7\
**Last updated:** [September 10, 2021, 9:08am UTC](https://discourse.julialang.org/t/upgrade-all-environments/67903 "2021-09-10T09:08:42Z")

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Is it possible upgrade all environments present in a machine at once? That is, instead of going project by project to upgrade packages, can I do that with a (few) commands?

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## [Avoiding memory allocation for solves with multiple right-hand sides](https://discourse.julialang.org/t/avoiding-memory-allocation-for-solves-with-multiple-right-hand-sides/67879)

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**Author:** [@Gravlax](https://discourse.julialang.org/u/Gravlax)\
**Replies:** 7\
**Last updated:** [September 10, 2021, 8:57am UTC](https://discourse.julialang.org/t/avoiding-memory-allocation-for-solves-with-multiple-right-hand-sides/67879 "2021-09-10T08:57:39Z")

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Hi everyone, I am new to Julia and I try to understand why a solve using the backslash operator allocates memory although the RHS vector is allocated, the solution vector is allocated and the factorisation is precompute…

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## [Sysimages - 2 questions - re-use, pitfalls, validity against current environment](https://discourse.julialang.org/t/sysimages-2-questions-re-use-pitfalls-validity-against-current-environment/67365)

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**Author:** [@ylvain](https://discourse.julialang.org/u/ylvain)\
**Replies:** 4\
**Last updated:** [September 3, 2021, 4:44pm UTC](https://discourse.julialang.org/t/sysimages-2-questions-re-use-pitfalls-validity-against-current-environment/67365 "2021-09-03T16:44:38Z")

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A custom sysimage seems to be the current (best?, only?) solution to the latency issue. Below I only talk about Sysimages, not about Apps or libraries. Contrary to the Apps case, I’m only concerned about weaker form of “…

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## ["error: ran out of registers during register allocation" Have you ever seen this message?](https://discourse.julialang.org/t/error-ran-out-of-registers-during-register-allocation-have-you-ever-seen-this-message/60153)

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**Author:** [@kimikage](https://discourse.julialang.org/u/kimikage)\
**Replies:** 10\
**Last updated:** [September 10, 2021, 7:52am UTC](https://discourse.julialang.org/t/error-ran-out-of-registers-during-register-allocation-have-you-ever-seen-this-message/60153 "2021-09-10T07:52:28Z")

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I encountered the following error message in the x86 (32-bit) Linux environment of GitHub Actions. error: ran out of registers during register allocation cf. https://github.com/kimikage/ColorBlendModes.jl/runs/24455061…

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## [\[ANN\] LightBSON.jl](https://discourse.julialang.org/t/ann-lightbson-jl/67437)

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**Author:** [@Christian\_Rorvik](https://discourse.julialang.org/u/Christian_Rorvik)\
**Replies:** 10\
**Last updated:** [September 10, 2021, 6:28am UTC](https://discourse.julialang.org/t/ann-lightbson-jl/67437 "2021-09-10T06:28:59Z")

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Borne out of a need for high performance and allocation free BSON processing, announcing LightBSON.jl. What It Is Allocation free API for reading and writing BSON data. Natural mapping of Julia types to corresponding B…

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## [Plotting errors when building documentation using Plots.jl and Documenter.jl](https://discourse.julialang.org/t/plotting-errors-when-building-documentation-using-plots-jl-and-documenter-jl/67849)

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**Author:** [@zengfung](https://discourse.julialang.org/u/zengfung)\
**Replies:** 7\
**Last updated:** [September 10, 2021, 5:57am UTC](https://discourse.julialang.org/t/plotting-errors-when-building-documentation-using-plots-jl-and-documenter-jl/67849 "2021-09-10T05:57:11Z")

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Hi all, I’m attempting to add plots into my package documentation using Plots.jl and Documenter.jl. However, creating a simple plot such as the following produces an error as below. Code in markdown file: using Plots …

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## [Creating a custom log message categorie](https://discourse.julialang.org/t/creating-a-custom-log-message-categorie/29295)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 20\
**Last updated:** [September 10, 2021, 4:54am UTC](https://discourse.julialang.org/t/creating-a-custom-log-message-categorie/29295 "2021-09-10T04:54:27Z")

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Hello, I am using the default Logger of Julia, and in the documentation it is mentioned that you can create custom log messages. I could not find out how, though. This works: using Logging logger = ConsoleLogger(stdo…

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## [Problems defining rrule for Flux layer](https://discourse.julialang.org/t/problems-defining-rrule-for-flux-layer/67952)

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**Author:** [@aross](https://discourse.julialang.org/u/aross)\
**Replies:** 1\
**Last updated:** [September 10, 2021, 4:06am UTC](https://discourse.julialang.org/t/problems-defining-rrule-for-flux-layer/67952 "2021-09-10T04:06:13Z")

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Hello, I am having trouble implementing the rrule for a Flux layer. I want to call Chain() with other Flux defined layers and then @train to update the parameters. The layer I’m defining is different, but I post a simpl…

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## [Unicode multiplication × and minus − signs could be recognized by Julia as the are by Google](https://discourse.julialang.org/t/unicode-multiplication-x-and-minus-signs-could-be-recognized-by-julia-as-the-are-by-google/67955)

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**Author:** [@oviedorodolfo](https://discourse.julialang.org/u/oviedorodolfo)\
**Replies:** 6\
**Last updated:** [September 9, 2021, 9:20pm UTC](https://discourse.julialang.org/t/unicode-multiplication-x-and-minus-signs-could-be-recognized-by-julia-as-the-are-by-google/67955 "2021-09-09T21:20:11Z")

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If there is no speed penalty or any other kind of penalty, it would be nice that Unicode characters × (00D7) and − (2212) be recognized by Julia as multiplication and minus operators as they are by Google. Sometimes I c…

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## [Julia alternatives to Matplotlib?](https://discourse.julialang.org/t/julia-alternatives-to-matplotlib/45445)

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**Author:** [@derekmahar](https://discourse.julialang.org/u/derekmahar)\
**Replies:** 83\
**Last updated:** [September 10, 2021, 2:36am UTC](https://discourse.julialang.org/t/julia-alternatives-to-matplotlib/45445 "2021-09-10T02:36:14Z")

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What are some alternatives to Python library Matplotlib but implemented in Julia?

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## [Makie | interactive update of colorrange in image! / heatmap!](https://discourse.julialang.org/t/makie-interactive-update-of-colorrange-in-image-heatmap/67887)

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**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 2\
**Last updated:** [September 10, 2021, 1:57am UTC](https://discourse.julialang.org/t/makie-interactive-update-of-colorrange-in-image-heatmap/67887 "2021-09-10T01:57:06Z")

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Hello, I am attempting to do an interactive update of colorrange in image! of the form image!( . . . colorrange = (window\_level\_min, window\_level\_max), . . . ) using input from two Sliders. window\_level\_min a…

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## [Is there a package that abstracts the storage location so that it's cloud and local path agnostic?](https://discourse.julialang.org/t/is-there-a-package-that-abstracts-the-storage-location-so-that-its-cloud-and-local-path-agnostic/67923)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 8\
**Last updated:** [September 9, 2021, 11:45pm UTC](https://discourse.julialang.org/t/is-there-a-package-that-abstracts-the-storage-location-so-that-its-cloud-and-local-path-agnostic/67923 "2021-09-09T23:45:15Z")

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Say I want to save a file somewhere on the hard drive, it’s actually not that different to saving it to a S3 bucket. E.g. save(location, object) should work regardless if the location is S3 or local path. Wonder if such…

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## [Return type not matching input type](https://discourse.julialang.org/t/return-type-not-matching-input-type/67904)

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**Author:** [@devin](https://discourse.julialang.org/u/devin)\
**Replies:** 13\
**Last updated:** [September 9, 2021, 7:51pm UTC](https://discourse.julialang.org/t/return-type-not-matching-input-type/67904 "2021-09-09T19:51:10Z")

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Today I tried something like this: data = rand(UInt8, 100, 100) data\_mod = mod.(data, 5) I noticed that my input type is UInt8 and the return type is Int64. Then I noticed this: function a()::UInt8 8 end function…

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## [Julia 1.6.2 now in conda-forge](https://discourse.julialang.org/t/julia-1-6-2-now-in-conda-forge/67949)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 2\
**Last updated:** [September 9, 2021, 8:11pm UTC](https://discourse.julialang.org/t/julia-1-6-2-now-in-conda-forge/67949 "2021-09-09T20:11:50Z")

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Julia 1.6.2 can now be installed via conda-forge: https://anaconda.org/conda-forge/julia Note that this is a custom build for conda-forge and is not the official Julia binaries. The main difference is that it uses cond…

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## [Julia on mobile: Ways to call Swift and/or Kotlin/Java on Android?](https://discourse.julialang.org/t/julia-on-mobile-ways-to-call-swift-and-or-kotlin-java-on-android/47534)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [September 30, 2020, 11:52am UTC](https://discourse.julialang.org/t/julia-on-mobile-ways-to-call-swift-and-or-kotlin-java-on-android/47534 "2020-09-30T11:52:39Z")

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First, I do view any non-JVM/Kotlin/Java apps to be non-native to Android, but might be mistaken about how inferior it is. People do a lot of JavaScript apps, I’m told. There’s also Kivy for Python Android apps, so Julia…

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## [Is it necessary to install all the packages listed in REQUIRE or Project.toml of a package?](https://discourse.julialang.org/t/is-it-necessary-to-install-all-the-packages-listed-in-require-or-project-toml-of-a-package/44165)

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**Author:** [@Ken\_Lin](https://discourse.julialang.org/u/Ken_Lin)\
**Replies:** 8\
**Last updated:** [September 9, 2021, 6:44pm UTC](https://discourse.julialang.org/t/is-it-necessary-to-install-all-the-packages-listed-in-require-or-project-toml-of-a-package/44165 "2021-09-09T18:44:54Z")

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Hello, In general, in Julia, if I add a package A through a URL from github, do I have to also install all the packages listed in the REQUIRE (or maybe Project.toml) of A, in order to use A normally? It seems that for…

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## [Performance of garbage collection](https://discourse.julialang.org/t/performance-of-garbage-collection/37698)

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**Author:** [@karelh](https://discourse.julialang.org/u/karelh)\
**Replies:** 5\
**Last updated:** [September 9, 2021, 6:41pm UTC](https://discourse.julialang.org/t/performance-of-garbage-collection/37698 "2021-09-09T18:41:34Z")

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I am trying to optimize the performance of training a neural network model (using Flux.jl and Mill.jl packages). I figured out that significant time is being spent on garbage collection (when @timing individual parts of …

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## [Cuprint makes CUDA kernell Work well](https://discourse.julialang.org/t/cuprint-makes-cuda-kernell-work-well/67821)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 1\
**Last updated:** [September 9, 2021, 5:31pm UTC](https://discourse.julialang.org/t/cuprint-makes-cuda-kernell-work-well/67821 "2021-09-09T17:31:09Z")

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I am developing kernel that is comparing two boolean 1 dimensional arrays looking for true positives, false positives and false negatives (details in function incr\_shmem below). And I have one bizarre error when I inc…

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## [Flux is lagging far beyond tensorflow with a pretty basic use case](https://discourse.julialang.org/t/flux-is-lagging-far-beyond-tensorflow-with-a-pretty-basic-use-case/67942)

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**Author:** [@egolep](https://discourse.julialang.org/u/egolep)\
**Replies:** 5\
**Last updated:** [September 9, 2021, 4:43pm UTC](https://discourse.julialang.org/t/flux-is-lagging-far-beyond-tensorflow-with-a-pretty-basic-use-case/67942 "2021-09-09T16:43:36Z")

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I was trying to move from a Python ML/DL stack to Julia (so from something like sklearn+pytorch/tensorflow to MLJ+Flux). So I decided to rewrite the Kaggle courses in Julia, switching from the Python libraries to the J…

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## [Makie.jl: travelling through an attractor (or Axis3)](https://discourse.julialang.org/t/makie-jl-travelling-through-an-attractor-or-axis3/67936)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 4\
**Last updated:** [September 9, 2021, 4:18pm UTC](https://discourse.julialang.org/t/makie-jl-travelling-through-an-attractor-or-axis3/67936 "2021-09-09T16:18:34Z")

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Hi, I have a 3d line plot that looks as follows: I know the ax.azimuth and ax.elevation I need to set to end up in this orientation. What I want to do now is somehow (no idea how!) animate the camera going through …

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## [PG fails to sample properly with acclogp!](https://discourse.julialang.org/t/pg-fails-to-sample-properly-with-acclogp/67924)

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**Author:** [@sami1](https://discourse.julialang.org/u/sami1)\
**Replies:** 2\
**Last updated:** [September 9, 2021, 3:33pm UTC](https://discourse.julialang.org/t/pg-fails-to-sample-properly-with-acclogp/67924 "2021-09-09T15:33:49Z")

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Hello, I’m currently trying to sample from a posterior with a mixture of differentiable and discrete parameters, some of them I can’t marginalize. I tried to marginalize the one I could using acclogp!, and sample the re…

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