# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1478

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

**Page:** 1479

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## [Most efficient way of calculating a multidimensional complex function many times](https://discourse.julialang.org/t/most-efficient-way-of-calculating-a-multidimensional-complex-function-many-times/55943)

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**Author:** [@O\_Julia](https://discourse.julialang.org/u/O_Julia)\
**Replies:** 7\
**Last updated:** [February 25, 2021, 8:56pm UTC](https://discourse.julialang.org/t/most-efficient-way-of-calculating-a-multidimensional-complex-function-many-times/55943 "2021-02-25T20:56:26Z")

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I have a very long function depends on X,Y,T. X and Y are vectors with length between 400-10000. I have to calculate the function in a for loop many times. Are my approachs efficient? If not, how can I improve them? Than…

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## [Recovering MATLAB addict needs help to understand Julia indexing](https://discourse.julialang.org/t/recovering-matlab-addict-needs-help-to-understand-julia-indexing/56046)

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**Author:** [@neuralian](https://discourse.julialang.org/u/neuralian)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 8:37pm UTC](https://discourse.julialang.org/t/recovering-matlab-addict-needs-help-to-understand-julia-indexing/56046 "2021-02-25T20:37:31Z")

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(In the REPL) Create a 1D array of 1D arrays of Points: julia\>using GLMakie julia\> A = fill(fill(Point2f0(0,0), 2), 2) 2-element Array{Array{Point{2,Float32},1},1}: \[\[0.0, 0.0\], \[0.0, 0.0\]\] \[\[0.0, 0.0\], \[0.0, 0.0\]\] C…

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## [Flag colors](https://discourse.julialang.org/t/flag-colors/55853)

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**Author:** [@gustaphe](https://discourse.julialang.org/u/gustaphe)\
**Replies:** 7\
**Last updated:** [February 25, 2021, 7:06pm UTC](https://discourse.julialang.org/t/flag-colors/55853 "2021-02-25T19:06:35Z")

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I made another dumb thing. Here’s a collection of flag colors. Do you think something like this would be useful to you? Is this a reasonable way to use it, or should it hook in to some other Colors functionality?

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## [Open EEG binary file](https://discourse.julialang.org/t/open-eeg-binary-file/55972)

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**Author:** [@VMHidalgo](https://discourse.julialang.org/u/VMHidalgo)\
**Replies:** 12\
**Last updated:** [February 25, 2021, 6:58pm UTC](https://discourse.julialang.org/t/open-eeg-binary-file/55972 "2021-02-25T18:58:00Z")

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Hi, I am trying to open an EEG BrainVision binary file, but I have a problem… Please help :frowning: To open the binary, I am using the solution provided in this discussion by @stevengj (thank you). The data is said t…

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## [Discourse display option for Latest](https://discourse.julialang.org/t/discourse-display-option-for-latest/56036)

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**Author:** [@devel-chm](https://discourse.julialang.org/u/devel-chm)\
**Replies:** 0\
**Last updated:** [February 25, 2021, 6:28pm UTC](https://discourse.julialang.org/t/discourse-display-option-for-latest/56036 "2021-02-25T18:28:54Z")

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I monitor the “New” page on Julia Discourse often. If I have time to “graze” more Julia I then go to the “Latest” page and take a look at topics that meet the following criteria: Are there unread messages in the topi…

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## [Turing fails to precompile](https://discourse.julialang.org/t/turing-fails-to-precompile/56011)

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**Author:** [@marouane1994](https://discourse.julialang.org/u/marouane1994)\
**Replies:** 4\
**Last updated:** [February 25, 2021, 6:24pm UTC](https://discourse.julialang.org/t/turing-fails-to-precompile/56011 "2021-02-25T18:24:07Z")

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I just installed Julia 1.5 and i started to add the packages and i added Turing.jl but when i type: julia\> using Turing i get this message: \[ Info: Precompiling Turing \[fce5fe82-541a-59a6-adf8-730c64b5f9a0\] ERROR: Loa…

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## [\[video\] A beginners guide to Bayesian Cognitive Modelling](https://discourse.julialang.org/t/video-a-beginners-guide-to-bayesian-cognitive-modelling/56025)

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**Author:** [@drbenvincent](https://discourse.julialang.org/u/drbenvincent)\
**Replies:** 4\
**Last updated:** [February 25, 2021, 5:52pm UTC](https://discourse.julialang.org/t/video-a-beginners-guide-to-bayesian-cognitive-modelling/56025 "2021-02-25T17:52:49Z")

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Just in case people here are interested, here is a video of a seminar talk I was invited to give to the Psychology department at the University of Leicester, UK. I go through some examples using Julia and Turing. As well…

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## [Not able to load a module from custom system image](https://discourse.julialang.org/t/not-able-to-load-a-module-from-custom-system-image/37571)

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**Author:** [@Vangelis](https://discourse.julialang.org/u/Vangelis)\
**Replies:** 5\
**Last updated:** [February 25, 2021, 5:07pm UTC](https://discourse.julialang.org/t/not-able-to-load-a-module-from-custom-system-image/37571 "2021-02-25T17:07:22Z")

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Dear experts, I have recently started using Julia because of its nice ability to create a binary out of the code. Apologies for the long post, but I am trying to give you the full picture. While I followed this documen…

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## [Can the compiler sometimes optimize small unions to avoid boxing?](https://discourse.julialang.org/t/can-the-compiler-sometimes-optimize-small-unions-to-avoid-boxing/56028)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 4:46pm UTC](https://discourse.julialang.org/t/can-the-compiler-sometimes-optimize-small-unions-to-avoid-boxing/56028 "2021-02-25T16:46:03Z")

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Hi, random question about performance: can the compiler sometimes optimize Union type variables so that there is no boxing or unboxing? For example, if I declare an “optional” integer type like Union{Nothing, Int}would t…

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## [How to record a video with WGLMakie/Atom without live plotting?](https://discourse.julialang.org/t/how-to-record-a-video-with-wglmakie-atom-without-live-plotting/54032)

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**Author:** [@sfmiller940](https://discourse.julialang.org/u/sfmiller940)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 4:05pm UTC](https://discourse.julialang.org/t/how-to-record-a-video-with-wglmakie-atom-without-live-plotting/54032 "2021-02-25T16:05:02Z")

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I’m using WGLMakie with Atom/Juno to record videos. Is it possible to record videos without live plotting in Atom? Sometimes I just want the video and live plotting seems like a drain on resources. Thanks!

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## [How do most people get around (not) compiling?](https://discourse.julialang.org/t/how-do-most-people-get-around-not-compiling/56016)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 14\
**Last updated:** [February 25, 2021, 3:45pm UTC](https://discourse.julialang.org/t/how-do-most-people-get-around-not-compiling/56016 "2021-02-25T15:45:07Z")

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This is more of a curiosity. Are most people using Julia to create scripts, in-house codes, and open source projects? Is there a significant group of people working with Julia for commercial software development? If so,…

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## [Sorting a Matrix by column1 then column2](https://discourse.julialang.org/t/sorting-a-matrix-by-column1-then-column2/55980)

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**Author:** [@eduardosalaz](https://discourse.julialang.org/u/eduardosalaz)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 3:24pm UTC](https://discourse.julialang.org/t/sorting-a-matrix-by-column1-then-column2/55980 "2021-02-25T15:24:34Z")

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So I am currently working on a greedy heuristic for knapsack, representing the values and weights of items in a 2D array. Basically I have to reverse sort the matrix first by col1, which puts the most profitable items on…

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## [Makie record without live plotting / sleep = false not implemented](https://discourse.julialang.org/t/makie-record-without-live-plotting-sleep-false-not-implemented/55991)

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**Author:** [@lazarusA](https://discourse.julialang.org/u/lazarusA)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 3:17pm UTC](https://discourse.julialang.org/t/makie-record-without-live-plotting-sleep-false-not-implemented/55991 "2021-02-25T15:17:23Z")

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Related to this question I did look into the source code and it seems like the option sleep = true or false is not implemented in order to avoid the live plotting. Is there another way to obtain the same effect ?

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## [Displaying a chess board with Julia](https://discourse.julialang.org/t/displaying-a-chess-board-with-julia/56015)

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**Author:** [@hpw](https://discourse.julialang.org/u/hpw)\
**Replies:** 0\
**Last updated:** [February 25, 2021, 1:56pm UTC](https://discourse.julialang.org/t/displaying-a-chess-board-with-julia/56015 "2021-02-25T13:56:39Z")

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I plan to use julia’s chess.jl and Gtk.jl + ImageView.pl to write a custom chess app for our kids to study puzzles. \[ We want to record what the kids did with elapsed time etc for e.g. Polgar’s ~5000 problems:) \] \[ The …

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## [A few questions on Julia's missing values, and how they compare to Python and R](https://discourse.julialang.org/t/a-few-questions-on-julias-missing-values-and-how-they-compare-to-python-and-r/56007)

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**Author:** [@yet\_another\_pythonis](https://discourse.julialang.org/u/yet_another_pythonis)\
**Replies:** 3\
**Last updated:** [February 25, 2021, 1:46pm UTC](https://discourse.julialang.org/t/a-few-questions-on-julias-missing-values-and-how-they-compare-to-python-and-r/56007 "2021-02-25T13:46:28Z")

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I have read a lot about how Julia handles missing values: https://docs.julialang.org/en/v1/manual/missing/ but what’s still not clear to me is the differences (and pros and cons) vs how Python and R treat them. Could …

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## [Benchmarking Parallel Computing Tools](https://discourse.julialang.org/t/benchmarking-parallel-computing-tools/56002)

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**Author:** [@zekeriya.sari](https://discourse.julialang.org/u/zekeriya.sari)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 12:48pm UTC](https://discourse.julialang.org/t/benchmarking-parallel-computing-tools/56002 "2021-02-25T12:48:38Z")

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I am trying to compare the performances of a couple of functions that solve a couple of differential equations. According to the benchmark results, the performance of the function that uses threads and distributed for ar…

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## [Countour/Contourf](https://discourse.julialang.org/t/countour-contourf/55933)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 16\
**Last updated:** [February 25, 2021, 12:36pm UTC](https://discourse.julialang.org/t/countour-contourf/55933 "2021-02-25T12:36:37Z")

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Plots.Controur() allows x,y,z to be Vector{Float64}. AbstractPlotting.Contour() chokes when I swap out the Plots version for the Makie version. ERROR: There was no \`AbstractPlotting.convert\_arguments\` overload found fo…

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## [Force calling the generic for benchmarking](https://discourse.julialang.org/t/force-calling-the-generic-for-benchmarking/56009)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 12:08pm UTC](https://discourse.julialang.org/t/force-calling-the-generic-for-benchmarking/56009 "2021-02-25T12:08:36Z")

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Consider the following dummy example: function f(x) println("We called the generic") prod(x) end function f(x::Real) println("We called the method") x end # Some checks: f(1) f(\[1 2\]) How can I force f…

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## [Question) How should I solve this equation from a finite-state Markov chain?](https://discourse.julialang.org/t/question-how-should-i-solve-this-equation-from-a-finite-state-markov-chain/55947)

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**Author:** [@Zerosum](https://discourse.julialang.org/u/Zerosum)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 11:25am UTC](https://discourse.julialang.org/t/question-how-should-i-solve-this-equation-from-a-finite-state-markov-chain/55947 "2021-02-25T11:25:37Z")

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I have 2,001 states, and say the transition matrix of Markov chain is given. Then there is a variable x(s) attached to each state s \\in \\{1,...,2001\\}, and I have to solve the following equation for any x(s): \\frac{a}{f…

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## [What does "DataFrame(columns::AbstractMatrix)\` is deprecated, use \`DataFrame(columns, :auto)\`" mean?](https://discourse.julialang.org/t/what-does-dataframe-columns-abstractmatrix-is-deprecated-use-dataframe-columns-auto-mean/55997)

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**Author:** [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 10:38am UTC](https://discourse.julialang.org/t/what-does-dataframe-columns-abstractmatrix-is-deprecated-use-dataframe-columns-auto-mean/55997 "2021-02-25T10:38:06Z")

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Hi, I re-ran some older code and see changes have been made. I tried following the discussion for this depreciation here but am not understanding the difference or what I need to do to update my code. The warning shows…

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## [Syntax validation of a julia file](https://discourse.julialang.org/t/syntax-validation-of-a-julia-file/55946)

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**Author:** [@artemsolod](https://discourse.julialang.org/u/artemsolod)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 10:26am UTC](https://discourse.julialang.org/t/syntax-validation-of-a-julia-file/55946 "2021-02-25T10:26:04Z")

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I am trying to come up with a script to check program’s syntax without running it. Ideally this should not rely on external packages as the goal in mind is to use this within online judge system at competitive programmin…

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## [How to create a MLJModelInterface.Model interface of a complex model?](https://discourse.julialang.org/t/how-to-create-a-mljmodelinterface-model-interface-of-a-complex-model/55860)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 10:26am UTC](https://discourse.julialang.org/t/how-to-create-a-mljmodelinterface-model-interface-of-a-complex-model/55860 "2021-02-25T10:26:19Z")

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Hi there, I am trying to build a MLJ interface for some ML algorithms in the BetaML package. I am starting from the Decision Trees, but I have a few questions. The function creating (and fitting) the tree is: buildTr…

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## [V0.7 Pkg: Passing arguments to test](https://discourse.julialang.org/t/v0-7-pkg-passing-arguments-to-test/12555)

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**Author:** [@v-i-s-h](https://discourse.julialang.org/u/v-i-s-h)\
**Replies:** 4\
**Last updated:** [February 25, 2021, 9:33am UTC](https://discourse.julialang.org/t/v0-7-pkg-passing-arguments-to-test/12555 "2021-02-25T09:33:54Z")

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Hi, Is there any way to pass arguments to test scripts when called via the Pkg REPL? From command line, I’m able to do $ julia ./test/runtests.jl \<args\> But is it possible to do similar from REPL, like (v0.7) pkg\> t…

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## [General questions about Pull requests and reviews](https://discourse.julialang.org/t/general-questions-about-pull-requests-and-reviews/55992)

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**Author:** [@dev\_prithvitewatia](https://discourse.julialang.org/u/dev_prithvitewatia)\
**Replies:** 2\
**Last updated:** [February 25, 2021, 8:06am UTC](https://discourse.julialang.org/t/general-questions-about-pull-requests-and-reviews/55992 "2021-02-25T08:06:12Z")

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Hello everyone, I am new to the Julia developer (Github) community though I have been using Julia for quite some time. I have few questions about the review of pull requests. How much time can it take to review a pull …

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## [Directly applying CuFFT on StructArrays](https://discourse.julialang.org/t/directly-applying-cufft-on-structarrays/55977)

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**Author:** [@weylspinor](https://discourse.julialang.org/u/weylspinor)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 7:43am UTC](https://discourse.julialang.org/t/directly-applying-cufft-on-structarrays/55977 "2021-02-25T07:43:43Z")

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I wonder if there is a way to use CuFFT directly on StructArrays{\<:Complex}. Currently, if I write e.g. using CUDA, StructArrays x\_re = rand(Float32, 10); x\_im = rand(Float32, 10); x = StructArray{ComplexF32}((x\_re,x\_im…

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## [In place updating of arrays](https://discourse.julialang.org/t/in-place-updating-of-arrays/55983)

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**Author:** [@praveenc](https://discourse.julialang.org/u/praveenc)\
**Replies:** 8\
**Last updated:** [February 25, 2021, 7:37am UTC](https://discourse.julialang.org/t/in-place-updating-of-arrays/55983 "2021-02-25T07:37:50Z")

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If we have array equation like x = x + y this creates extra memory allocation. Does the following do in place update x .= x + y How to find out if the update is happening in place ?

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## [Makie record a video with audio](https://discourse.julialang.org/t/makie-record-a-video-with-audio/55990)

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**Author:** [@lazarusA](https://discourse.julialang.org/u/lazarusA)\
**Replies:** 0\
**Last updated:** [February 25, 2021, 7:31am UTC](https://discourse.julialang.org/t/makie-record-a-video-with-audio/55990 "2021-02-25T07:31:20Z")

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Hello, I know that the the record function one cannot include also some audio. Any suggestions for a work around ?

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## [Makie.jl: Limiting height of Colorbar to that of a nearby equal-aspect axis](https://discourse.julialang.org/t/makie-jl-limiting-height-of-colorbar-to-that-of-a-nearby-equal-aspect-axis/55876)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 6\
**Last updated:** [February 25, 2021, 6:57am UTC](https://discourse.julialang.org/t/makie-jl-limiting-height-of-colorbar-to-that-of-a-nearby-equal-aspect-axis/55876 "2021-02-25T06:57:52Z")

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Hi there, I have the following code: fig, abmstepper = abm\_plot(model) ax, hm = heatmap(fig\[1,2\], model.sugar\_capacities; colormap=cgrad(:thermal)) ax.aspect = AxisAspect(1) # equal aspect ratio for heatmap Colorbar(fi…

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## [Threaded map and reduce problem](https://discourse.julialang.org/t/threaded-map-and-reduce-problem/55903)

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**Author:** [@Adriel](https://discourse.julialang.org/u/Adriel)\
**Replies:** 5\
**Last updated:** [February 25, 2021, 4:39am UTC](https://discourse.julialang.org/t/threaded-map-and-reduce-problem/55903 "2021-02-25T04:39:05Z")

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I have a bottleneck matrix-vector product and reduction that I’m trying to speed up. Any multithreading gurus that could point me to a suitable parallel mapreduce implementation? The current code is function nonthreaded…

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## [Is it worth introducing \`copy()\` into learnxiny?](https://discourse.julialang.org/t/is-it-worth-introducing-copy-into-learnxiny/55965)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 4\
**Last updated:** [February 25, 2021, 4:11am UTC](https://discourse.julialang.org/t/is-it-worth-introducing-copy-into-learnxiny/55965 "2021-02-25T04:11:39Z")

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Many new users use: Learn Julia in Y Minutes New users coming from Matlab/Octave (like myself) may not realize that using = w/ arrays does not create a new copy. a1 = \[1:5;\] a2 = a1 a2\[5\] = a2\[5\] +40 a2 a1 # a1 = \[1:5…

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