# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=251

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**Page:** 252

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## [TrajectoryOptimization.jl minimal time problem](https://discourse.julialang.org/t/trajectoryoptimization-jl-minimal-time-problem/82795)

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**Author:** [@a6a3uh](https://discourse.julialang.org/u/a6a3uh)\
**Replies:** 17\
**Last updated:** [September 13, 2022, 6:13pm UTC](https://discourse.julialang.org/t/trajectoryoptimization-jl-minimal-time-problem/82795 "2022-09-13T18:13:12Z")

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Maybe some of authors of the package are around here to answer the question. Is it possible to formulate minimal time trajectory optimization problem with TrajectoryOptimization.jl? How can I go about if I don’t know in …

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## [Automatic bifurcation diagram for a simple model](https://discourse.julialang.org/t/automatic-bifurcation-diagram-for-a-simple-model/87227)

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**Author:** [@zmoitier](https://discourse.julialang.org/u/zmoitier)\
**Replies:** 0\
**Last updated:** [September 13, 2022, 5:43pm UTC](https://discourse.julialang.org/t/automatic-bifurcation-diagram-for-a-simple-model/87227 "2022-09-13T17:43:11Z")

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I am trying to compute the bifurcation diagram using BifucationKit.jl associated to the equation: find a vector u and a scalar λ such that Au - λu - u.^3 = 0 where A is a real symmetric matrix. For this problem, the theo…

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## [Migrating old html posts to Franklin](https://discourse.julialang.org/t/migrating-old-html-posts-to-franklin/87214)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [September 13, 2022, 3:52pm UTC](https://discourse.julialang.org/t/migrating-old-html-posts-to-franklin/87214 "2022-09-13T15:52:36Z")

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I would like to migrate my old Hugo-based setup to Franklin. I am not going to re-edit the Markdown files, so I just want to copy over everything (generated HTML) in post/ so that the old links indexed in search engines…

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## [Using fixed points from dynamicalsystems.jl in BifurcationKit.jl](https://discourse.julialang.org/t/using-fixed-points-from-dynamicalsystems-jl-in-bifurcationkit-jl/87213)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 4\
**Last updated:** [September 13, 2022, 2:08pm UTC](https://discourse.julialang.org/t/using-fixed-points-from-dynamicalsystems-jl-in-bifurcationkit-jl/87213 "2022-09-13T14:08:19Z")

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I find fixed points by changing two parameters of a continuous system using the fixed point() function. How correctly use finded fixed points for plotting bifurcation diagram by BifurcationKit.jl? Are there any examp…

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## [Robust date conversion from string to DateTime](https://discourse.julialang.org/t/robust-date-conversion-from-string-to-datetime/87215)

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**Author:** [@scotts](https://discourse.julialang.org/u/scotts)\
**Replies:** 1\
**Last updated:** [September 13, 2022, 2:01pm UTC](https://discourse.julialang.org/t/robust-date-conversion-from-string-to-datetime/87215 "2022-09-13T14:01:47Z")

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I am having to convert dates in the following string format “24/9/2020” to DateTime format. DateTime does not deal with this basic format. I have come up with the following solution that does this for the data I’m deal…

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## [Video Frame Stacking for Nightsky videos](https://discourse.julialang.org/t/video-frame-stacking-for-nightsky-videos/87211)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 0\
**Last updated:** [September 13, 2022, 12:15pm UTC](https://discourse.julialang.org/t/video-frame-stacking-for-nightsky-videos/87211 "2022-09-13T12:15:12Z")

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Anyone using Julia to do frame stacking to enhance night images of the sky from Webcams or Iphones, etc.

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## [Mapslices very slow](https://discourse.julialang.org/t/mapslices-very-slow/86826)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 3\
**Last updated:** [September 13, 2022, 11:56am UTC](https://discourse.julialang.org/t/mapslices-very-slow/86826 "2022-09-13T11:56:53Z")

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new to CUDA mapsilces seems to run very slow. reduce is very fast but requires an accumulator (e.g. +) instead of a function (e.g. sum). I’d like to apply the linear\_interpolation function to slices of a matrix (or t…

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## [ReinforcementLearning Gym spaces](https://discourse.julialang.org/t/reinforcementlearning-gym-spaces/87061)

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**Author:** [@chunky](https://discourse.julialang.org/u/chunky)\
**Replies:** 2\
**Last updated:** [September 13, 2022, 6:46am UTC](https://discourse.julialang.org/t/reinforcementlearning-gym-spaces/87061 "2022-09-13T06:46:51Z")

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I have a C++ Gym exposed as a C .dll/.so whose API was originally designed to be used for a Python OpenAI Gym using ctypes. Specifically, this only relies on “Box” for both action and observation; the continuous, multidi…

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## [About examples in format validation from inmemorydatasets documents](https://discourse.julialang.org/t/about-examples-in-format-validation-from-inmemorydatasets-documents/86640)

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**Author:** [@akshdfyehd](https://discourse.julialang.org/u/akshdfyehd)\
**Replies:** 1\
**Last updated:** [September 13, 2022, 4:17am UTC](https://discourse.julialang.org/t/about-examples-in-format-validation-from-inmemorydatasets-documents/86640 "2022-09-13T04:17:16Z")

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Hi, I am relatively new to Julia, I can’t find the example for content inside red lines, can someone please make an example? How to show in Julia that changing the definition of the formats destroys the sorting order of …

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## [Using local module with @everywhere](https://discourse.julialang.org/t/using-local-module-with-everywhere/87163)

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**Author:** [@bojeryd91](https://discourse.julialang.org/u/bojeryd91)\
**Replies:** 2\
**Last updated:** [September 12, 2022, 9:38pm UTC](https://discourse.julialang.org/t/using-local-module-with-everywhere/87163 "2022-09-12T21:38:31Z")

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Hi, my goal is to within one script define a module only once in my local scope, and then read it to all my workers. However, I cannot figure out what to do. This is my MWE: using Distributed module myModule export f f…

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## [Easy way to send custom function to distributed workers?](https://discourse.julialang.org/t/easy-way-to-send-custom-function-to-distributed-workers/22118)

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**Author:** [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Replies:** 3\
**Last updated:** [September 12, 2022, 8:35pm UTC](https://discourse.julialang.org/t/easy-way-to-send-custom-function-to-distributed-workers/22118 "2022-09-12T20:35:07Z")

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Is there a way to pass a function to workers? e.g. using Distributed addprocs(4) function my\_func(x) return x ^ 2 end \[send my function to everyone\] pmap(my\_func, 1:100) I recognize I can do something like: @ev…

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## [How to extract intermediate results from GMRES of Krylov.jl](https://discourse.julialang.org/t/how-to-extract-intermediate-results-from-gmres-of-krylov-jl/87019)

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**Author:** [@jinml](https://discourse.julialang.org/u/jinml)\
**Replies:** 7\
**Last updated:** [September 12, 2022, 7:10pm UTC](https://discourse.julialang.org/t/how-to-extract-intermediate-results-from-gmres-of-krylov-jl/87019 "2022-09-12T19:10:05Z")

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Hi, I am using gmres from Krylov.jl as follows x,stat=gmres(A,b,itmax=3000,memory=500,history=true) which will return some information about the iteration, e.g., stat.residuals. Is there a way to also return the interm…

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## [Drawing a circle](https://discourse.julialang.org/t/drawing-a-circle/87154)

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**Author:** [@Niall](https://discourse.julialang.org/u/Niall)\
**Replies:** 2\
**Last updated:** [September 12, 2022, 6:34pm UTC](https://discourse.julialang.org/t/drawing-a-circle/87154 "2022-09-12T18:34:08Z")

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Hello. Can anyone please tell me what I’m doing wrong here? I just want to draw a circle at the point (1,2), but I can’t find any circle, ellipse or rectangle drawing commands in Makie. julia\> using GLMakie julia\> funct…

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## [LightOSM : reading GeoJSON files](https://discourse.julialang.org/t/lightosm-reading-geojson-files/87131)

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**Author:** [@imantha](https://discourse.julialang.org/u/imantha)\
**Replies:** 1\
**Last updated:** [September 12, 2022, 1:22pm UTC](https://discourse.julialang.org/t/lightosm-reading-geojson-files/87131 "2022-09-12T13:22:42Z")

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Hi I am attempting to use the Agents.jl library to design ABM with OpenStreetMapSpace, which uses the features from LightOSM.jl. Unfortunately the road network require (for the country guadeloupe) is unavailable to be do…

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## [DataFrame with mix types](https://discourse.julialang.org/t/dataframe-with-mix-types/87134)

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**Author:** [@lgmendes](https://discourse.julialang.org/u/lgmendes)\
**Replies:** 1\
**Last updated:** [September 12, 2022, 1:36pm UTC](https://discourse.julialang.org/t/dataframe-with-mix-types/87134 "2022-09-12T13:36:23Z")

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How can I create a dataframe with only one row composed by a Vector and a Int . When I do DataFrame(a=\[1,2,3\],b=1) the result dataFrame is a 3x2 DataFrame of Ints.

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## [How to identify oscillatory conditions in Julia ODEs?](https://discourse.julialang.org/t/how-to-identify-oscillatory-conditions-in-julia-odes/81824)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 24\
**Last updated:** [September 12, 2022, 11:59am UTC](https://discourse.julialang.org/t/how-to-identify-oscillatory-conditions-in-julia-odes/81824 "2022-09-12T11:59:46Z")

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Dear all, I am simulating bacterial infections and I would like to know if there is a way to spot cases when the population enters an oscillatory equilibrium, for instance, as in this case: To note that the two theo…

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## [Seasonal storage balance constraint](https://discourse.julialang.org/t/seasonal-storage-balance-constraint/87098)

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**Author:** [@mbah](https://discourse.julialang.org/u/mbah)\
**Replies:** 3\
**Last updated:** [September 12, 2022, 7:11am UTC](https://discourse.julialang.org/t/seasonal-storage-balance-constraint/87098 "2022-09-12T07:11:58Z")

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Hello all, I am trying to code up a seasonal storage balance constraint. The idea is to limit the total generation over a time range by a particular amount for each of the seasonal storage plants (see Table). I have tr…

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## [How Bayesian estimation of parameters of ODE system is done?](https://discourse.julialang.org/t/how-bayesian-estimation-of-parameters-of-ode-system-is-done/87092)

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**Author:** [@vembha](https://discourse.julialang.org/u/vembha)\
**Replies:** 4\
**Last updated:** [September 11, 2022, 10:19pm UTC](https://discourse.julialang.org/t/how-bayesian-estimation-of-parameters-of-ode-system-is-done/87092 "2022-09-11T22:19:46Z")

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Hello people, I tried to find texts, journal articles, blog posts, etc., to understand how Bayesian estimation (for example, NUTS) works for ODE parameter estimation, but I could not. None of the material I found on the…

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## [BitVector Adapt GPUs](https://discourse.julialang.org/t/bitvector-adapt-gpus/86500)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 25\
**Last updated:** [September 11, 2022, 9:52pm UTC](https://discourse.julialang.org/t/bitvector-adapt-gpus/86500 "2022-09-11T21:52:54Z")

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I have a custom type which contains a BitVector. struct customType{T\<:AbstractFloat} code::BitVector s\_chipLength::T … end I’m trying to use Adapt.@adapt\_structure customType{Float64} It still fails with isbitstyp…

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## [How can I pass the pointer of MPI communicator to c function?](https://discourse.julialang.org/t/how-can-i-pass-the-pointer-of-mpi-communicator-to-c-function/87070)

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**Author:** [@dora\_ho](https://discourse.julialang.org/u/dora_ho)\
**Replies:** 3\
**Last updated:** [September 11, 2022, 8:55pm UTC](https://discourse.julialang.org/t/how-can-i-pass-the-pointer-of-mpi-communicator-to-c-function/87070 "2022-09-11T20:55:51Z")

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I have a c function that requires me to pass a comm pointer to the function I converted the function using Clang.jl showed below function Comm(comm\_handle) ccall((:Comm, librarypath), Cint, (Ptr{Cvoid}), comm\_hand…

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## [Efficiently creating a data frame that is made up of smaller data frames](https://discourse.julialang.org/t/efficiently-creating-a-data-frame-that-is-made-up-of-smaller-data-frames/87055)

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**Author:** [@erickawaguchi](https://discourse.julialang.org/u/erickawaguchi)\
**Replies:** 5\
**Last updated:** [September 11, 2022, 10:25am UTC](https://discourse.julialang.org/t/efficiently-creating-a-data-frame-that-is-made-up-of-smaller-data-frames/87055 "2022-09-11T10:25:43Z")

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Hi all, I’m trying to create a “long” version data frame (e.g. several observations per individual as in a longitudinal study). However, the data frame for each individual will depend on certain parameters - not the sam…

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## [Displaying multiple plots at the same time](https://discourse.julialang.org/t/displaying-multiple-plots-at-the-same-time/87054)

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**Author:** [@neuro\_enthusiast](https://discourse.julialang.org/u/neuro_enthusiast)\
**Replies:** 4\
**Last updated:** [September 11, 2022, 9:38am UTC](https://discourse.julialang.org/t/displaying-multiple-plots-at-the-same-time/87054 "2022-09-11T09:38:24Z")

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Hi all, I was trying to plot multiple Gadfly plots and display them in two separate figures. However, only the second plot was displayed. function draw\_stuff() Gadfly.plot(x=\[1,1,2,2\],\[3,4,5,6\],Geom.violin) Gadfly.p…

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## [When are two expressions equal?](https://discourse.julialang.org/t/when-are-two-expressions-equal/87045)

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**Author:** [@qwerty](https://discourse.julialang.org/u/qwerty)\
**Replies:** 1\
**Last updated:** [September 10, 2022, 6:31pm UTC](https://discourse.julialang.org/t/when-are-two-expressions-equal/87045 "2022-09-10T18:31:37Z")

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We know that an expression can be written in various forms. For example: (x - 2)^2 and 4 + x^2 - 4x are the same function. Given a set of substitution rules (such as the default ones in SymbolicUtils.jl), what is the be…

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## [SymbolicUtils: LiteralReal](https://discourse.julialang.org/t/symbolicutils-literalreal/87044)

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**Author:** [@qwerty](https://discourse.julialang.org/u/qwerty)\
**Replies:** 0\
**Last updated:** [September 10, 2022, 5:14pm UTC](https://discourse.julialang.org/t/symbolicutils-literalreal/87044 "2022-09-10T17:14:22Z")

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When should the LiteralReal type be used? How can I convert an expression that contains LiteralReal types?

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## [Can we require at least Julia 1.6 in DataFrames.jl](https://discourse.julialang.org/t/can-we-require-at-least-julia-1-6-in-dataframes-jl/86959)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 21\
**Last updated:** [September 10, 2022, 1:18pm UTC](https://discourse.julialang.org/t/can-we-require-at-least-julia-1-6-in-dataframes-jl/86959 "2022-09-10T13:18:18Z")

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DataFrames.jl currently supports Julia 1.0. We would like to drop this support and require at least Julia 1.6. If anyone objects to this please comment in this thread. Thank you!

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## [Error when supplying initial guess](https://discourse.julialang.org/t/error-when-supplying-initial-guess/86574)

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**Author:** [@ivzktch99](https://discourse.julialang.org/u/ivzktch99)\
**Replies:** 6\
**Last updated:** [September 10, 2022, 11:56am UTC](https://discourse.julialang.org/t/error-when-supplying-initial-guess/86574 "2022-09-10T11:56:02Z")

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If I set my variable to be lower trianglar, how can I supply an initial guess? The following gives me an error that has to do with the difference in the data type between the variable X and the initial guess X0 using Ju…

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## [Getting started with ReinforcementLearning.jl](https://discourse.julialang.org/t/getting-started-with-reinforcementlearning-jl/87011)

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**Author:** [@bwanab](https://discourse.julialang.org/u/bwanab)\
**Replies:** 1\
**Last updated:** [September 10, 2022, 7:54am UTC](https://discourse.julialang.org/t/getting-started-with-reinforcementlearning-jl/87011 "2022-09-10T07:54:09Z")

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In ReinforcementLearningAnIntroduction/notebooks/Chapter01\_Tic\_Tac\_Toe.jl in the Testing section there is the comment “I leave it as an exercise to change the select\_action to a greedy version and confirm that our traine…

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## [Mosek.jl not compiling in Julia 1.8 (Apple Silicon M1)](https://discourse.julialang.org/t/mosek-jl-not-compiling-in-julia-1-8-apple-silicon-m1/87024)

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**Author:** [@raktim](https://discourse.julialang.org/u/raktim)\
**Replies:** 1\
**Last updated:** [September 10, 2022, 1:23am UTC](https://discourse.julialang.org/t/mosek-jl-not-compiling-in-julia-1-8-apple-silicon-m1/87024 "2022-09-10T01:23:22Z")

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Mosek.jl is not compiling in Julia 1.8 macOS ARM (M-series Processor). It is unable to load libmosek (~/.julia/packages/Mosek/3NJdY/deps/src/mosek/9.3/tools/platform/osx64x86/bin/libmosek64.9.3.dylib). It is probably an…

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## [\[Makie\] Latex in tick labels](https://discourse.julialang.org/t/makie-latex-in-tick-labels/86980)

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**Author:** [@whatsthecraic](https://discourse.julialang.org/u/whatsthecraic)\
**Replies:** 3\
**Last updated:** [September 9, 2022, 4:15pm UTC](https://discourse.julialang.org/t/makie-latex-in-tick-labels/86980 "2022-09-09T16:15:06Z")

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How do you render a latex expression for the ticks in a Makie plot ? Example: ax = Axis(Figure()\[1,1\]) xlims!(ax, 1, nothing) ax.xscale = log2 ax.xticks = (\[1, 8, 32\], \[L"2^0", L"2^3", L"2^5"\]) values = \[1,2,3,4,5,6\] p…

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## [Inline animation using PyPlot](https://discourse.julialang.org/t/inline-animation-using-pyplot/86992)

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**Author:** [@KK\_JuliaNoob](https://discourse.julialang.org/u/KK_JuliaNoob)\
**Replies:** 0\
**Last updated:** [September 9, 2022, 2:23pm UTC](https://discourse.julialang.org/t/inline-animation-using-pyplot/86992 "2022-09-09T14:23:18Z")

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Is there a simple example of using PyPlot to create animated SVG plots inline in a Jupyter notebook? Ideally, I’d like to do this without writing to a file first.

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