# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1220

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

**Page:** 1221

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## [Implementing Dry friction in modeling toolkit](https://discourse.julialang.org/t/implementing-dry-friction-in-modeling-toolkit/70743)

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**Author:** [@yjr](https://discourse.julialang.org/u/yjr)\
**Replies:** 1\
**Last updated:** [November 1, 2021, 4:38pm UTC](https://discourse.julialang.org/t/implementing-dry-friction-in-modeling-toolkit/70743 "2021-11-01T16:38:30Z")

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Hello, I would like to implement some function to have components simulating dry friction with modeling toolkit. As a starting point, I think the implementation from modelica is quite good. Most of it can be implemented…

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## [Randomized Hypothesis Test (row-level analysis): DimensionMismatch ERROR](https://discourse.julialang.org/t/randomized-hypothesis-test-row-level-analysis-dimensionmismatch-error/70663)

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**Author:** [@YummyPampers2](https://discourse.julialang.org/u/YummyPampers2)\
**Replies:** 16\
**Last updated:** [November 1, 2021, 3:47pm UTC](https://discourse.julialang.org/t/randomized-hypothesis-test-row-level-analysis-dimensionmismatch-error/70663 "2021-11-01T15:47:49Z")

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Hello Everyone, Using = Pluto 0.17.\* using Combinatorics, StatsBase Am working with the following DF P1 = DataFrame(Col1 = rand(1:5:100,10), Col2 = rand(1:3:150,10), Col3=rand(1:4:250,10) and another dataframe where…

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## [Color a polygon](https://discourse.julialang.org/t/color-a-polygon/6248)

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**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 2\
**Last updated:** [November 1, 2021, 3:47pm UTC](https://discourse.julialang.org/t/color-a-polygon/6248 "2021-11-01T15:47:44Z")

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Hi, I have a flat polygon in 3d and I would like to color it. So far, I could not do it. Please note that I do not want to decompose it with triangles. Thank you for your help, Best regards using Plots t=linspace(0,2…

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## [Plotting Continuous Error Bars](https://discourse.julialang.org/t/plotting-continuous-error-bars/70587)

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**Author:** [@YummyPampers2](https://discourse.julialang.org/u/YummyPampers2)\
**Replies:** 11\
**Last updated:** [November 1, 2021, 3:42pm UTC](https://discourse.julialang.org/t/plotting-continuous-error-bars/70587 "2021-11-01T15:42:23Z")

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Hello Everyone, Are there any libraries out there that help continuous error plots with a small series of values. For example, x = \[1,4,7,3,5,6,10,7\] y = \[1,2,3,4,5,6,7,8\] Using the coefficient of variance, or some…

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## [Improving the start banner with BetterBanner.jl](https://discourse.julialang.org/t/improving-the-start-banner-with-betterbanner-jl/70711)

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**Author:** [@longemen3000](https://discourse.julialang.org/u/longemen3000)\
**Replies:** 8\
**Last updated:** [November 1, 2021, 1:19pm UTC](https://discourse.julialang.org/t/improving-the-start-banner-with-betterbanner-jl/70711 "2021-11-01T13:19:14Z")

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All started in the Humans of Julia discord server, when one user was showcasing julia on a mobile device, and one thing that standed out was that the start banner text overflows, ruining the julia logo. A similar thing …

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## [A \* B \* A' is not hermitian, even when B is](https://discourse.julialang.org/t/a-b-a-is-not-hermitian-even-when-b-is/70611)

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**Author:** [@jlbosse](https://discourse.julialang.org/u/jlbosse)\
**Replies:** 8\
**Last updated:** [November 1, 2021, 1:17pm UTC](https://discourse.julialang.org/t/a-b-a-is-not-hermitian-even-when-b-is/70611 "2021-11-01T13:17:11Z")

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The title essentially says it all: If I create a hermitian matrix A with julia\> R = randn(10,10) julia\> A = R \* R' # definitely hermitian and positive semidefinite and another arbitrary matrix B julia\> B = rand(7, 10…

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## [Question about UMAP](https://discourse.julialang.org/t/question-about-umap/70733)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 1\
**Last updated:** [November 1, 2021, 1:10pm UTC](https://discourse.julialang.org/t/question-about-umap/70733 "2021-11-01T13:10:05Z")

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I performed the following operations, but Julia reported an error \]add UMAP ERROR: Unsatisfiable requirements detected for package Reexport \[189a3867\]: Reexport \[189a3867\] log: ├─possible versions are: 0.2.0-1.2.2 or…

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## [Get true maximum value of a raster](https://discourse.julialang.org/t/get-true-maximum-value-of-a-raster/70622)

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**Author:** [@CompulsoryCoffee](https://discourse.julialang.org/u/CompulsoryCoffee)\
**Replies:** 4\
**Last updated:** [November 1, 2021, 11:25am UTC](https://discourse.julialang.org/t/get-true-maximum-value-of-a-raster/70622 "2021-11-01T11:25:41Z")

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Hi, I have raster which I would like to get the maximum value from using ArchGDAL but I get only the (I believe 98th percentile (as it is done in QGIS) using ArchGDAL const AG = ArchGDAL dataset = AG.readraster("rast…

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## [3D Heatmap](https://discourse.julialang.org/t/3d-heatmap/70658)

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**Author:** [@skolari93](https://discourse.julialang.org/u/skolari93)\
**Replies:** 8\
**Last updated:** [November 1, 2021, 10:48am UTC](https://discourse.julialang.org/t/3d-heatmap/70658 "2021-11-01T10:48:05Z")

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Hello! Is there a way creatinge a 3D heatplot using Plots.jl? I try to visualize a 4D plot by plotting a 3D sphere and coloring the surface according to a function f. This is the closest I was able to do: plot(x,y,z,…

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## [Qt platform plugin required for PyPlot](https://discourse.julialang.org/t/qt-platform-plugin-required-for-pyplot/70725)

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**Author:** [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)\
**Replies:** 0\
**Last updated:** [November 1, 2021, 9:48am UTC](https://discourse.julialang.org/t/qt-platform-plugin-required-for-pyplot/70725 "2021-11-01T09:48:19Z")

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I have removed the .julia directory and used Pkg package manager to install PyPlot only in Julia 1.6.3 on a Windows machine. qt.qpa.plugin returns an error. julia\> versioninfo() Julia Version 1.6.3 Commit ae8452a9e0 (20…

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## [Trouble understanding how plot recipes dispatches customized types containing other customized types](https://discourse.julialang.org/t/trouble-understanding-how-plot-recipes-dispatches-customized-types-containing-other-customized-types/60357)

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**Author:** [@kapple](https://discourse.julialang.org/u/kapple)\
**Replies:** 9\
**Last updated:** [November 1, 2021, 9:33am UTC](https://discourse.julialang.org/t/trouble-understanding-how-plot-recipes-dispatches-customized-types-containing-other-customized-types/60357 "2021-11-01T09:33:33Z")

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Can someone explain why the following doesn’t work? julia\> using RecipesBase julia\> struct Pair x::Vector{Float64} y::Vector{Float64} end julia\> struct Pairs pairs::Vector{Pair}…

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## [Any collaborative filtering by rank-constrained matrix factoristion in Julia?](https://discourse.julialang.org/t/any-collaborative-filtering-by-rank-constrained-matrix-factoristion-in-julia/70723)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 0\
**Last updated:** [November 1, 2021, 8:45am UTC](https://discourse.julialang.org/t/any-collaborative-filtering-by-rank-constrained-matrix-factoristion-in-julia/70723 "2021-11-01T08:45:22Z")

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Hello, which is the state of the art package for collaborative filtering/missing imputation in julia using rank-constrained matrix factorisation and regularisation ? For example for constrained rank 1, the missing point…

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## [Apple M1, M1 pro M1 Max and Julia developpers](https://discourse.julialang.org/t/apple-m1-m1-pro-m1-max-and-julia-developpers/70627)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 17\
**Last updated:** [November 1, 2021, 8:37am UTC](https://discourse.julialang.org/t/apple-m1-m1-pro-m1-max-and-julia-developpers/70627 "2021-11-01T08:37:39Z")

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I would like to know what Julia developers may have to share about Julia development on apple silicon (M1) machines. What is nice, what is wrong, is it possible to use GLMakie, multi-threading perfs and so on…

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## [Reversing Axis of the plot](https://discourse.julialang.org/t/reversing-axis-of-the-plot/58604)

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**Author:** [@tgautam03](https://discourse.julialang.org/u/tgautam03)\
**Replies:** 1\
**Last updated:** [November 1, 2021, 5:51am UTC](https://discourse.julialang.org/t/reversing-axis-of-the-plot/58604 "2021-11-01T05:51:06Z")

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Hi, I’m plotting using Plots and noticed that by default 0,0 is at bottom left. Is there any way by which I can move this to top left (i.e. reverse y-axis). Thanks

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## [Incorporating forcing functions in the ODE model](https://discourse.julialang.org/t/incorporating-forcing-functions-in-the-ode-model/70133)

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**Author:** [@vembha](https://discourse.julialang.org/u/vembha)\
**Replies:** 28\
**Last updated:** [November 1, 2021, 2:15am UTC](https://discourse.julialang.org/t/incorporating-forcing-functions-in-the-ode-model/70133 "2021-11-01T02:15:01Z")

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Hello, I am new to Turing and Julia, and need some help! I have been trying to estimate the parameters of a model with a discrete forcing function q(t), where the values of q(t) are discrete and are read from a file. C…

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## [About training strategy](https://discourse.julialang.org/t/about-training-strategy/70528)

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**Author:** [@iiisoo](https://discourse.julialang.org/u/iiisoo)\
**Replies:** 2\
**Last updated:** [November 1, 2021, 1:43am UTC](https://discourse.julialang.org/t/about-training-strategy/70528 "2021-11-01T01:43:55Z")

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I am trying to run the example of PINN soling PDE( https://github.com/SciML/NeuralPDE.jl ) But when I use the: discretization = PhysicsInformedNN(chain, QuadratureTraining(),init\_params =initθ) in later part of: i…

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## [Best linting support at the moment](https://discourse.julialang.org/t/best-linting-support-at-the-moment/70706)

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**Author:** [@martinmestre](https://discourse.julialang.org/u/martinmestre)\
**Replies:** 0\
**Last updated:** [November 1, 2021, 12:24am UTC](https://discourse.julialang.org/t/best-linting-support-at-the-moment/70706 "2021-11-01T00:24:36Z")

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Hello, I would like to know which editor gives best linting support at the moment. I tried with VS Code+Julia (+LanguageServer although I read later that this is not needed explicitly) but it didn’t lint basic errors lik…

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## [Cannot start Julia 1.7 rc2](https://discourse.julialang.org/t/cannot-start-julia-1-7-rc2/70629)

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**Author:** [@matthieu](https://discourse.julialang.org/u/matthieu)\
**Replies:** 1\
**Last updated:** [October 29, 2021, 9:24pm UTC](https://discourse.julialang.org/t/cannot-start-julia-1-7-rc2/70629 "2021-10-29T21:24:23Z")

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I cannot launch Julia 1.7 rc2 after updating to Monterey (macOS 12.0). When I try to launch it in the Terminal, I get the error: fatal: error thrown and no exception handler available. InitError(mod=:Sys, error=ErrorExc…

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## [Turing models: Errors when generating random numbers using parameters (Tracked reals)](https://discourse.julialang.org/t/turing-models-errors-when-generating-random-numbers-using-parameters-tracked-reals/70702)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 0\
**Last updated:** [October 31, 2021, 8:28pm UTC](https://discourse.julialang.org/t/turing-models-errors-when-generating-random-numbers-using-parameters-tracked-reals/70702 "2021-10-31T20:28:34Z")

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Inside a Turing model, for some generated quantities, I’m doing rand(Normal(0.0,scale)) where “scale” is a parameter. I’m getting an error: ERROR: LoadError: MethodError: no method matching randn(::Random.\_GLOBAL\_RNG, …

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## [For loop optimization](https://discourse.julialang.org/t/for-loop-optimization/70700)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 3\
**Last updated:** [October 31, 2021, 7:39pm UTC](https://discourse.julialang.org/t/for-loop-optimization/70700 "2021-10-31T19:39:39Z")

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Hello, I’m not sure how to optimize the following for loop. array\_1 and array\_2 are two Vector{Vector{Int64}}s, and I’m interested in evaluating which combinations (of 2 elements) of their vector components has an elem…

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## [Local infeasibility, Ipopt](https://discourse.julialang.org/t/local-infeasibility-ipopt/70026)

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**Author:** [@FH96](https://discourse.julialang.org/u/FH96)\
**Replies:** 13\
**Last updated:** [October 31, 2021, 9:30pm UTC](https://discourse.julialang.org/t/local-infeasibility-ipopt/70026 "2021-10-31T21:30:35Z")

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what can I do if the optimization results in “Converged to a point of local infeasibility. Problem may be infeasible.” despite of changing the start point? I am using JuMP+Ipopt

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## [How to remove the box around the legend in PyPlot.jl](https://discourse.julialang.org/t/how-to-remove-the-box-around-the-legend-in-pyplot-jl/25528)

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**Author:** [@mirtah](https://discourse.julialang.org/u/mirtah)\
**Replies:** 7\
**Last updated:** [October 31, 2021, 8:54pm UTC](https://discourse.julialang.org/t/how-to-remove-the-box-around-the-legend-in-pyplot-jl/25528 "2021-10-31T20:54:38Z")

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hi. I would like to remove the box around the legend in my plot. May I ask you to how to do this. Sorry , I am new to Julia. this is the code I use. version of Julia :1.1.1 using PyPlot x=\[1,2,3,4\] y=x figure() …

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## [Parallelization of for loop](https://discourse.julialang.org/t/parallelization-of-for-loop/70557)

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**Author:** [@Germinator](https://discourse.julialang.org/u/Germinator)\
**Replies:** 3\
**Last updated:** [October 31, 2021, 7:52pm UTC](https://discourse.julialang.org/t/parallelization-of-for-loop/70557 "2021-10-31T19:52:45Z")

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Dear Julia users, I am trying to parallelize the following loop, what do you think is the best approach? for n = 1:N kron!(temp,A\[n,:\],B\[n,:\]) C.+= temp.\*temp' Cx .+= tem…

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## [When a function requires a Vector that contains a concrete type, is it necessary to generate optimized code?](https://discourse.julialang.org/t/when-a-function-requires-a-vector-that-contains-a-concrete-type-is-it-necessary-to-generate-optimized-code/70667)

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**Author:** [@Nadia.Sweet](https://discourse.julialang.org/u/Nadia.Sweet)\
**Replies:** 16\
**Last updated:** [October 31, 2021, 7:13pm UTC](https://discourse.julialang.org/t/when-a-function-requires-a-vector-that-contains-a-concrete-type-is-it-necessary-to-generate-optimized-code/70667 "2021-10-31T19:13:39Z")

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Suppose if you’re writing a function that will sort elements in a vector, perhaps insertion sort. function insertion\_sort!(unsorted\_list) # Don't worry about implementation. end Performance Tips: In many languag…

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## [Levels keyword but for scatter plot](https://discourse.julialang.org/t/levels-keyword-but-for-scatter-plot/70697)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 3\
**Last updated:** [October 31, 2021, 6:57pm UTC](https://discourse.julialang.org/t/levels-keyword-but-for-scatter-plot/70697 "2021-10-31T18:57:48Z")

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Hi! The levels keyword of surface is useful: fig = Figure() xs = LinRange(0, 20, 50) ys = LinRange(0, 15, 50) zs = \[cos(x) \* sin(y) for x in xs, y in ys\] ax, hm = contourf(fig\[1, 1\], xs, ys, zs, colormap = :Spectr…

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## [Understanding how an array of structures works](https://discourse.julialang.org/t/understanding-how-an-array-of-structures-works/46011)

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**Author:** [@rjmoses](https://discourse.julialang.org/u/rjmoses)\
**Replies:** 31\
**Last updated:** [October 31, 2021, 6:14pm UTC](https://discourse.julialang.org/t/understanding-how-an-array-of-structures-works/46011 "2021-10-31T18:14:17Z")

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I tripped across something that I just plain don’t understand when using an array to contain a structure. If I have a structure created outside a for loop and try to assign it to an element of the array, I do not get t…

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## [Dispatch on type aliases?](https://discourse.julialang.org/t/dispatch-on-type-aliases/70691)

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**Author:** [@NightMachinary](https://discourse.julialang.org/u/NightMachinary)\
**Replies:** 7\
**Last updated:** [October 31, 2021, 5:23pm UTC](https://discourse.julialang.org/t/dispatch-on-type-aliases/70691 "2021-10-31T17:23:12Z")

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Can Julia have dispatch based on type aliases? Something rather similar to Scala 3’s opaque type aliases. const MyTypeAlias = Float64 a::MyTypeAlias = 78.0 # The compiler should implicitly convert this from Float64 to M…

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## [Conditionally defining a macro](https://discourse.julialang.org/t/conditionally-defining-a-macro/70690)

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**Author:** [@Mark\_Nahabedian](https://discourse.julialang.org/u/Mark_Nahabedian)\
**Replies:** 1\
**Last updated:** [October 31, 2021, 4:37pm UTC](https://discourse.julialang.org/t/conditionally-defining-a-macro/70690 "2021-10-31T16:37:20Z")

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I want to be able to modify a bunch of definitions depending on whether another file is included. In the parlance of Aspect Oriented programming, that file would implement an aspect which I could optionally include. I …

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## [DAEs and Turing](https://discourse.julialang.org/t/daes-and-turing/70651)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 9\
**Last updated:** [October 31, 2021, 4:11pm UTC](https://discourse.julialang.org/t/daes-and-turing/70651 "2021-10-31T16:11:28Z")

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1. Model and DifferentialEquations I’m trying to estimate initial values and parameters in a DAE using Turing. The structure of the DAE is as follows: \\frac{dx}{dt} = f(x,z,u;\\theta) \\\\ 0 = g(x,z,u;\\theta) I have avai…

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## [PyPlot crashes REPL after re-install](https://discourse.julialang.org/t/pyplot-crashes-repl-after-re-install/70685)

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**Author:** [@Fred\_He](https://discourse.julialang.org/u/Fred_He)\
**Replies:** 3\
**Last updated:** [October 31, 2021, 4:03pm UTC](https://discourse.julialang.org/t/pyplot-crashes-repl-after-re-install/70685 "2021-10-31T16:03:08Z")

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Hello community, I deleted the miniconda by mistake, then installed back again. Unfortunately the pyplot doesn’t work anymore. I found the python version in miniconda is updated to 3.9, while the previous one was 3.7. I…

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