# Latest

**URL:** https://discourse.julialang.org/latest.md?page=542

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

**Page:** 543

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## [Transitioning 3D surface plot to Makie v0.20](https://discourse.julialang.org/t/transitioning-3d-surface-plot-to-makie-v0-20/106928)

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**Author:** [@yhchang96](https://discourse.julialang.org/u/yhchang96)\
**Replies:** 1\
**Last updated:** [November 30, 2023, 10:46am UTC](https://discourse.julialang.org/t/transitioning-3d-surface-plot-to-makie-v0-20/106928 "2023-11-30T10:46:56Z")

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I had a figure which consists of multiple 3D surface plots. The script looks something like using CairoMakie; CairoMakie.activate!() update\_theme!(Surface = (diffuse = Vec3f(1,0), specular = Vec3f(0.2), shading = true)…

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## [Continuously tracking callback with boolean condition](https://discourse.julialang.org/t/continuously-tracking-callback-with-boolean-condition/106937)

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**Author:** [@flmuk](https://discourse.julialang.org/u/flmuk)\
**Replies:** 1\
**Last updated:** [November 30, 2023, 9:50am UTC](https://discourse.julialang.org/t/continuously-tracking-callback-with-boolean-condition/106937 "2023-11-30T09:50:07Z")

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Hello, I have the following system of equations: using DifferentialEquations using Plots u\_rest = -50. t\_ref = 2. u\_reset = -75. u\_thr = -55. J = 1. last\_spikes = \[1., 1.\] .\* (- t\_ref + eps()) function decay(du, u, p…

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## [Zero-allocating Instance of Struct](https://discourse.julialang.org/t/zero-allocating-instance-of-struct/106893)

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**Author:** [@PatrickHaecker](https://discourse.julialang.org/u/PatrickHaecker)\
**Replies:** 11\
**Last updated:** [November 30, 2023, 9:58am UTC](https://discourse.julialang.org/t/zero-allocating-instance-of-struct/106893 "2023-11-30T09:58:52Z")

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I have large structs with a lot of fields (think of multiple 100s) which I need to communicate with a C library. Julia creates the instances of a struct (memory allocation) but C fills in the values. Keeping its memory u…

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## [Julia Users Helsinki: kickstart meeting 21 September 2022](https://discourse.julialang.org/t/julia-users-helsinki-kickstart-meeting-21-september-2022/86800)

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**Author:** [@lferrant](https://discourse.julialang.org/u/lferrant)\
**Replies:** 6\
**Last updated:** [November 30, 2023, 8:53am UTC](https://discourse.julialang.org/t/julia-users-helsinki-kickstart-meeting-21-september-2022/86800 "2023-11-30T08:53:12Z")

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I’m glad to announce the first Julia Users meetup in Helsinki area on 21st September 2022 in Otaniemi. Doesn’t metter if you are new to julia or experienced user, if you are enthusiast you are welcome to join! The first…

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## [Efficient Broadcasting in Julia: CartesianIndex vs. Reshape](https://discourse.julialang.org/t/efficient-broadcasting-in-julia-cartesianindex-vs-reshape/106929)

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**Author:** [@swanchristmas](https://discourse.julialang.org/u/swanchristmas)\
**Replies:** 1\
**Last updated:** [November 30, 2023, 8:12am UTC](https://discourse.julialang.org/t/efficient-broadcasting-in-julia-cartesianindex-vs-reshape/106929 "2023-11-30T08:12:22Z")

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I came across a discussion post on using \[CartesianIndex()\] for singleton insertion in Julia arrays. Intrigued by potential performance differences, I conducted a benchmark comparing it with the reshape method. Benchmar…

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## [Makie: PDF paper size (or MadiaBox)?](https://discourse.julialang.org/t/makie-pdf-paper-size-or-madiabox/106900)

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**Author:** [@ryofurue](https://discourse.julialang.org/u/ryofurue)\
**Replies:** 13\
**Last updated:** [November 30, 2023, 7:11am UTC](https://discourse.julialang.org/t/makie-pdf-paper-size-or-madiabox/106900 "2023-11-30T07:11:40Z")

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How do you specify the paper size of the PDF image? Alternatively, how do you control the physical size of the axes? I must be fundamentally misunderstanding how the sizing of the plot works. In the example at the end…

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## [Return (1,), what is the meaning?](https://discourse.julialang.org/t/return-1-what-is-the-meaning/106924)

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**Author:** [@jiang\_ming\_zhang](https://discourse.julialang.org/u/jiang_ming_zhang)\
**Replies:** 2\
**Last updated:** [November 30, 2023, 3:25am UTC](https://discourse.julialang.org/t/return-1-what-is-the-meaning/106924 "2023-11-30T03:25:16Z")

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I am new to Julia. The following code is from some people’s package: function apply\_column!(::IsDeterministic, w, op::AbstractMatrix, add, val, boost=1) w .+= op\[:, add\] .\* val return (1,) end What does return (…

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## [I'm making a Julia wargame! What kind of special effects do you want?](https://discourse.julialang.org/t/im-making-a-julia-wargame-what-kind-of-special-effects-do-you-want/106521)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 10\
**Last updated:** [November 30, 2023, 2:55am UTC](https://discourse.julialang.org/t/im-making-a-julia-wargame-what-kind-of-special-effects-do-you-want/106521 "2023-11-30T02:55:49Z")

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I am making a turn-based hex strategy wargame. I have the following code. struct StatusEffect #??? #Working in progress. end struct TileFeature #??? #Working in progress. end struct WeaponFeature …

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## [Implementing derivative in ChainRules for function with internal fields](https://discourse.julialang.org/t/implementing-derivative-in-chainrules-for-function-with-internal-fields/66844)

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**Author:** [@jcallaham](https://discourse.julialang.org/u/jcallaham)\
**Replies:** 5\
**Last updated:** [November 30, 2023, 2:06am UTC](https://discourse.julialang.org/t/implementing-derivative-in-chainrules-for-function-with-internal-fields/66844 "2023-11-30T02:06:25Z")

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I’m trying to define an rrule for a functional, e.g. numerical integration of a given function, and the gradient would be with respect to the parameters of the function. This works no problem with a simple implementatio…

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## [Subtour elimination constraints](https://discourse.julialang.org/t/subtour-elimination-constraints/106902)

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**Author:** [@Victor\_Neto](https://discourse.julialang.org/u/Victor_Neto)\
**Replies:** 15\
**Last updated:** [November 30, 2023, 1:58am UTC](https://discourse.julialang.org/t/subtour-elimination-constraints/106902 "2023-11-30T01:58:34Z")

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Dear colleagues, I am studying the school bus routing problem: Redirecting. I am reproducing this mixed-integer linear programming formulation. However, I was replacing the sub-tour constraints (3) with a flow constrai…

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## [Vscode language server crashing](https://discourse.julialang.org/t/vscode-language-server-crashing/90185)

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**Author:** [@sransome](https://discourse.julialang.org/u/sransome)\
**Replies:** 17\
**Last updated:** [November 30, 2023, 1:32am UTC](https://discourse.julialang.org/t/vscode-language-server-crashing/90185 "2023-11-30T01:32:00Z")

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Hi, for the last month or so, every time my Windows 10 computer gets rebooted the language server will not start when I try to open my Julia project. I have tried reinstalling the Julia extension, Julia itself and V…

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## [Running NUTS with a categorical prior?](https://discourse.julialang.org/t/running-nuts-with-a-categorical-prior/106871)

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**Author:** [@Alejandro\_Quiaro\_San](https://discourse.julialang.org/u/Alejandro_Quiaro_San)\
**Replies:** 8\
**Last updated:** [November 29, 2023, 11:16pm UTC](https://discourse.julialang.org/t/running-nuts-with-a-categorical-prior/106871 "2023-11-29T23:16:28Z")

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Hello guys. I’m new to Turing.jl and I’m having some trouble building my model. It is supposed to be a relatively simple model. I have a forward operator called “MT” that takes 3 vectors as input (d,rho,f) and outputs “…

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## [Yggdrasil: LoadError: Dependency HDF5\_jll specifies a version, use build\_version and/or compat instead](https://discourse.julialang.org/t/yggdrasil-loaderror-dependency-hdf5-jll-specifies-a-version-use-build-version-and-or-compat-instead/68134)

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**Author:** [@Alexander-Barth](https://discourse.julialang.org/u/Alexander-Barth)\
**Replies:** 1\
**Last updated:** [November 29, 2023, 10:19pm UTC](https://discourse.julialang.org/t/yggdrasil-loaderror-dependency-hdf5-jll-specifies-a-version-use-build-version-and-or-compat-instead/68134 "2023-11-29T22:19:30Z")

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I am trying to update the NetCDF library in Yggdrasil. First I would like to build the tar files locally, however I get the following error (before making any changes to build\_tarballs.jl): cd Yggdrasil/N/NetCDF/NetCDF@…

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## [Julia Language Server keep crashing, even after reinstall](https://discourse.julialang.org/t/julia-language-server-keep-crashing-even-after-reinstall/67002)

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**Author:** [@jeffreyesun](https://discourse.julialang.org/u/jeffreyesun)\
**Replies:** 8\
**Last updated:** [November 29, 2023, 7:41pm UTC](https://discourse.julialang.org/t/julia-language-server-keep-crashing-even-after-reinstall/67002 "2023-11-29T19:41:50Z")

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I hope this is the right place to post this, but recently vscode has become almost unusable because of how often the language server crashes and has to restart. I’ve already uninstalled julia and vscode, and deleted ~/.j…

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## [SBRP problem with capacity os bus](https://discourse.julialang.org/t/sbrp-problem-with-capacity-os-bus/106719)

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**Author:** [@Victor\_Neto](https://discourse.julialang.org/u/Victor_Neto)\
**Replies:** 5\
**Last updated:** [November 29, 2023, 7:23pm UTC](https://discourse.julialang.org/t/sbrp-problem-with-capacity-os-bus/106719 "2023-11-29T19:23:11Z")

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I’m trying to model a problem with school transport routes, however, according to the code below, whenever the bus capacity is exceeded by the number of students, the code presents an error. I don’t know which constraint…

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## [Getting precompilation error for SymPy](https://discourse.julialang.org/t/getting-precompilation-error-for-sympy/106899)

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**Author:** [@Sahil\_Khan](https://discourse.julialang.org/u/Sahil_Khan)\
**Replies:** 1\
**Last updated:** [November 29, 2023, 7:10pm UTC](https://discourse.julialang.org/t/getting-precompilation-error-for-sympy/106899 "2023-11-29T19:10:51Z")

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I’m getting this error while trying to precompile SymPy \[ Info: Precompiling SymPy \[24249f21-da20-56a4-8eb1-6a02cf4ae2e6\] Python path configuration: PYTHONHOME = '/Users/sahil.khan/.julia/conda/3:/Users/sahil.khan/.ju…

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## ["What's in your Julia and Quarto?"](https://discourse.julialang.org/t/whats-in-your-julia-and-quarto/91254)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 10\
**Last updated:** [November 29, 2023, 7:07pm UTC](https://discourse.julialang.org/t/whats-in-your-julia-and-quarto/91254 "2023-11-29T19:07:20Z")

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Some of us are using Quarto with Julia, so I thought it would be nice to have a permanent thread on this topic taking inspiration from What is in your startup.jl? by @oxinabox. It would be great to hear about everyone’s …

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## [Installation or guidance](https://discourse.julialang.org/t/installation-or-guidance/106911)

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**Author:** [@Stayal](https://discourse.julialang.org/u/Stayal)\
**Replies:** 1\
**Last updated:** [November 29, 2023, 6:49pm UTC](https://discourse.julialang.org/t/installation-or-guidance/106911 "2023-11-29T18:49:55Z")

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Hello everyone I am Shivangi Tayal, beginner on Julia and Gridap. I want to use Gridap for writting codes for Finite Element Method. Please guide me on installation process (or tell me where I have to install it Linux o…

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## [Still do not understand difference between diagonal and scalar noise](https://discourse.julialang.org/t/still-do-not-understand-difference-between-diagonal-and-scalar-noise/106860)

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**Author:** [@acubed](https://discourse.julialang.org/u/acubed)\
**Replies:** 2\
**Last updated:** [November 29, 2023, 6:14pm UTC](https://discourse.julialang.org/t/still-do-not-understand-difference-between-diagonal-and-scalar-noise/106860 "2023-11-29T18:14:16Z")

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I have system of N coupled stochastic differential equations, that looks like \\displaystyle\\frac{du\_i}{dt}=F(u\_i)+\\eta\_i here F is the function that mixes u\_i with u\_j. The quantity \\eta\_i is so-called white noise with…

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## [Issues solving a bilevel optimization with binary variables](https://discourse.julialang.org/t/issues-solving-a-bilevel-optimization-with-binary-variables/105460)

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**Author:** [@kiki](https://discourse.julialang.org/u/kiki)\
**Replies:** 3\
**Last updated:** [November 29, 2023, 5:44pm UTC](https://discourse.julialang.org/t/issues-solving-a-bilevel-optimization-with-binary-variables/105460 "2023-11-29T17:44:23Z")

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I’m new using Julia to solve my nonlinear mixed integer bilevel model, so I have a model in JuMP using BilevelJuMP with binary and continuous variables at the lower and upper level and with non-linear \[non quadratic\] co…

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## [Xpress with bilinear models (the model is MIQCP)](https://discourse.julialang.org/t/xpress-with-bilinear-models-the-model-is-miqcp/106680)

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**Author:** [@martina.gherardi](https://discourse.julialang.org/u/martina.gherardi)\
**Replies:** 7\
**Last updated:** [November 29, 2023, 5:37pm UTC](https://discourse.julialang.org/t/xpress-with-bilinear-models-the-model-is-miqcp/106680 "2023-11-29T17:37:01Z")

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Hi, I am trying to use Xpress on a model with bilinear terms. With linear models it works while with my bilinear model I obtain: ?900 Warning: The quadratic part of row 'R21577' defines a nonconvex region. Please chec…

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## [Adjoint of 2d diffusion using SciMLSensitivity](https://discourse.julialang.org/t/adjoint-of-2d-diffusion-using-scimlsensitivity/106863)

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**Author:** [@Alberto\_Roman](https://discourse.julialang.org/u/Alberto_Roman)\
**Replies:** 3\
**Last updated:** [November 29, 2023, 5:23pm UTC](https://discourse.julialang.org/t/adjoint-of-2d-diffusion-using-scimlsensitivity/106863 "2023-11-29T17:23:39Z")

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I am trying to try to solve the adjoint problem of 2d diffusion using SciMLSensitivity. My test case follow the 1d case given at Partial Differential Equation (PDE) Constrained Optimization · SciMLSensitivity.jl Howeve…

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## [Julia 1.10.0-rc1 hangs on Pkg.status() with high thread count](https://discourse.julialang.org/t/julia-1-10-0-rc1-hangs-on-pkg-status-with-high-thread-count/106905)

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**Author:** [@sebastien-lemieux](https://discourse.julialang.org/u/sebastien-lemieux)\
**Replies:** 4\
**Last updated:** [November 29, 2023, 5:20pm UTC](https://discourse.julialang.org/t/julia-1-10-0-rc1-hangs-on-pkg-status-with-high-thread-count/106905 "2023-11-29T17:20:46Z")

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Hello, I’m currently experimenting with 1.10.0-rc1 and I encountered a strange issue. I’m launching julia with JULIA\_NUM\_THREADS=auto on 3 AMD computers in the lab. On two threadripper (32 and 24 cores) everything works…

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## [ModelingToolkit, vars to varmap?](https://discourse.julialang.org/t/modelingtoolkit-vars-to-varmap/106904)

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**Author:** [@rpex](https://discourse.julialang.org/u/rpex)\
**Replies:** 6\
**Last updated:** [November 29, 2023, 4:37pm UTC](https://discourse.julialang.org/t/modelingtoolkit-vars-to-varmap/106904 "2023-11-29T16:37:37Z")

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Hello, Is there a function to get the index from variable names in ModelingToolkit.jl? Or a function that returns me a varmap (Vector{Pair{Num, Float64}})? So the opposite of ModelingToolkit.varmap\_to\_vars() I’m curr…

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## [Jl\_call - function call latency](https://discourse.julialang.org/t/jl-call-function-call-latency/106791)

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**Author:** [@AntoineK](https://discourse.julialang.org/u/AntoineK)\
**Replies:** 5\
**Last updated:** [November 29, 2023, 3:59pm UTC](https://discourse.julialang.org/t/jl-call-function-call-latency/106791 "2023-11-29T15:59:06Z")

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Hello, My first benchmarks show that calling the jl\_call function comes with a latency of 100 nanoseconds (measured by calling an empty Julia function) on a Xeon Gold processor. Is it expected ? In Julia, BenchmarksTo…

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## [ModelingToolkit for (continuous) Model ID with (discrete) input and output data](https://discourse.julialang.org/t/modelingtoolkit-for-continuous-model-id-with-discrete-input-and-output-data/106889)

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**Author:** [@rpex](https://discourse.julialang.org/u/rpex)\
**Replies:** 3\
**Last updated:** [November 29, 2023, 3:19pm UTC](https://discourse.julialang.org/t/modelingtoolkit-for-continuous-model-id-with-discrete-input-and-output-data/106889 "2023-11-29T15:19:19Z")

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I want to model a quadrocpter with MTK. In the first step I want to identify the parameters of a simple model from real flight data. In the second step I want to learn not yet modeled effects from the data by different e…

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## [What constitutes a good post here?](https://discourse.julialang.org/t/what-constitutes-a-good-post-here/106777)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 5\
**Last updated:** [November 27, 2023, 7:15pm UTC](https://discourse.julialang.org/t/what-constitutes-a-good-post-here/106777 "2023-11-27T19:15:25Z")

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This forum has a bunch of guidelines and some rough descriptions of what each topic is. The community guideline says what constitutes a bad post, but it doesn’t tell you what a good post is. Sometimes, misaligned expecta…

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## [Plotting daily death using Makie](https://discourse.julialang.org/t/plotting-daily-death-using-makie/106895)

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**Author:** [@Chao](https://discourse.julialang.org/u/Chao)\
**Replies:** 5\
**Last updated:** [November 29, 2023, 1:09pm UTC](https://discourse.julialang.org/t/plotting-daily-death-using-makie/106895 "2023-11-29T13:09:48Z")

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Hello, I am plotting the daily new death per day. It should be a line, but it looks strange. Here are my codes: # read the data covid\_death = filter(row -\> row.location == "Germany" && row.date \>= Date(2020, 6, 1) &&…

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## [What materials should I read extending the compiler?](https://discourse.julialang.org/t/what-materials-should-i-read-extending-the-compiler/106841)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 14\
**Last updated:** [November 29, 2023, 1:09pm UTC](https://discourse.julialang.org/t/what-materials-should-i-read-extending-the-compiler/106841 "2023-11-29T13:09:21Z")

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I have some knowledge of metaprogramming from my last package. Now, I need to descend into madness, to figure out how the compiler works and how I can access and modify the working of each stage in the pipeline. Impleme…

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## [Row / column major with PythonCall , OpenCV](https://discourse.julialang.org/t/row-column-major-with-pythoncall-opencv/106620)

<div class="topic-metadata">

**Author:** [@kemu](https://discourse.julialang.org/u/kemu)\
**Replies:** 18\
**Last updated:** [November 29, 2023, 12:15pm UTC](https://discourse.julialang.org/t/row-column-major-with-pythoncall-opencv/106620 "2023-11-29T12:15:27Z")

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row / column major with PythonCall and numpy + OpenCV I am trying to create an image processing program using PythonCall.jl and the Python version of OpenCV. The specification I have in mind now is to create the pixel …

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