# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=53

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**Page:** 54

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## [See progress in partialschur in ArnoldiMethod.jl](https://discourse.julialang.org/t/see-progress-in-partialschur-in-arnoldimethod-jl/130542)

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**Author:** [@eveningsilverfox](https://discourse.julialang.org/u/eveningsilverfox)\
**Replies:** 0\
**Last updated:** [July 7, 2025, 6:54pm UTC](https://discourse.julialang.org/t/see-progress-in-partialschur-in-arnoldimethod-jl/130542 "2025-07-07T18:54:40Z")

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Is there any way to see the progress in partialschur? decomp, history = partialschur(LinearMap(x-\>Mapfunc(x,args), N), nev=1, which=:SR); Eval, Evec = partialeigen(decomp);

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## [Gridap.jl: Add tags to faces of 3D models](https://discourse.julialang.org/t/gridap-jl-add-tags-to-faces-of-3d-models/130526)

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**Author:** [@Van\_Sy\_Tnut](https://discourse.julialang.org/u/Van_Sy_Tnut)\
**Replies:** 6\
**Last updated:** [July 7, 2025, 6:48pm UTC](https://discourse.julialang.org/t/gridap-jl-add-tags-to-faces-of-3d-models/130526 "2025-07-07T18:48:38Z")

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Hello everyone, I am new to Gridap.jl. I am creating a 3D model of a cantilever beam to apply a distributed load on the right face, and the left face is fixed. Do you know how to add tags to LEFT and RIGHT faces ? Her…

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## [Help Me Drive an E-Ink Display on a Raspberry Pi Using Julia!](https://discourse.julialang.org/t/help-me-drive-an-e-ink-display-on-a-raspberry-pi-using-julia/123972)

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**Author:** [@TheCedarPrince](https://discourse.julialang.org/u/TheCedarPrince)\
**Replies:** 19\
**Last updated:** [July 7, 2025, 3:30pm UTC](https://discourse.julialang.org/t/help-me-drive-an-e-ink-display-on-a-raspberry-pi-using-julia/123972 "2025-07-07T15:30:18Z")

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Hi folks! :wave: I am on a quest to use Julia to drive an E-Ink Display that I am running from a Raspberry Pi 4 (Raspbian OS 64-bit). Here is an image of what I would like to be seeing happen: This is using a Python l…

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## [How to move .julia directory to another partition in GNU/Linux?](https://discourse.julialang.org/t/how-to-move-julia-directory-to-another-partition-in-gnu-linux/103258)

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**Author:** [@archisman](https://discourse.julialang.org/u/archisman)\
**Replies:** 4\
**Last updated:** [July 7, 2025, 2:19pm UTC](https://discourse.julialang.org/t/how-to-move-julia-directory-to-another-partition-in-gnu-linux/103258 "2025-07-07T14:19:34Z")

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I am using Julia on a Chromebook running Ubuntu. The computer has very limited internal storage (only 32 GB), and I want to move the .julia directory to a microSD card, because it consumes several gigabytes of space. Th…

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## [EnsembleSummary of SDEProblem with output\_func gives incorrect dimensions](https://discourse.julialang.org/t/ensemblesummary-of-sdeproblem-with-output-func-gives-incorrect-dimensions/130516)

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**Author:** [@Rodrigo\_Zepeda](https://discourse.julialang.org/u/Rodrigo_Zepeda)\
**Replies:** 2\
**Last updated:** [July 7, 2025, 12:06am UTC](https://discourse.julialang.org/t/ensemblesummary-of-sdeproblem-with-output-func-gives-incorrect-dimensions/130516 "2025-07-07T00:06:14Z")

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I’m using DifferentialEquations.jl to solve an SDEProblem with a custom output\_func. I am then trying to summarize multiple trajectories with EnsembleSummary. However, the resulting summary has the wrong dimensions for t…

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## [UniversalKriging, gauged precipiation interpolation with dem as a covariate](https://discourse.julialang.org/t/universalkriging-gauged-precipiation-interpolation-with-dem-as-a-covariate/130519)

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**Author:** [@kongdd](https://discourse.julialang.org/u/kongdd)\
**Replies:** 1\
**Last updated:** [July 6, 2025, 6:54pm UTC](https://discourse.julialang.org/t/universalkriging-gauged-precipiation-interpolation-with-dem-as-a-covariate/130519 "2025-07-06T18:54:16Z")

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The following script is the UniversalKriging script gived by grok 3.5, which is trying to interpolate gauged precipiation with dem as a covariate. Any idea how to achieve this in Julia? import numpy as np from pykrige.…

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## [Why does padding around plots get increasingly large when there are more subplots?](https://discourse.julialang.org/t/why-does-padding-around-plots-get-increasingly-large-when-there-are-more-subplots/130503)

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**Author:** [@miles-1](https://discourse.julialang.org/u/miles-1)\
**Replies:** 1\
**Last updated:** [July 5, 2025, 11:40pm UTC](https://discourse.julialang.org/t/why-does-padding-around-plots-get-increasingly-large-when-there-are-more-subplots/130503 "2025-07-05T23:40:53Z")

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I’m trying to make a single figure that is very long with many subplots. However, plotting behavior seems to change the larger the image gets. Specifically, the padding between the plots and the axes’ number labels seem …

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## [How to stop array slice being flattened](https://discourse.julialang.org/t/how-to-stop-array-slice-being-flattened/130494)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 2\
**Last updated:** [July 5, 2025, 4:03pm UTC](https://discourse.julialang.org/t/how-to-stop-array-slice-being-flattened/130494 "2025-07-05T16:03:51Z")

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Julia is removing singular dimensions when I slice an array: A = reshape(\[2 2 2 2\], 2, 1, 2) A\[1,1,:\] 2-element Vector{Int64}: 2 2 If I want A to remain a 1x1x2 array, is there anything I can do other than reshape it…

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## [Performance discrepancy in solving sparse SPD\\dense rhs between X86 and Apple M](https://discourse.julialang.org/t/performance-discrepancy-in-solving-sparse-spd-dense-rhs-between-x86-and-apple-m/130476)

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**Author:** [@pitsianis](https://discourse.julialang.org/u/pitsianis)\
**Replies:** 2\
**Last updated:** [July 4, 2025, 8:06pm UTC](https://discourse.julialang.org/t/performance-discrepancy-in-solving-sparse-spd-dense-rhs-between-x86-and-apple-m/130476 "2025-07-04T20:06:43Z")

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Why do I observe a 9x difference in elapsed times when I run the following on my macbook laptop using Random, SparseArrays, LinearAlgebra Random.seed!(0); A = sprand(10000,10000,5/10000) + I; A = max.(A,A'); b = rand(…

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## [DocumenterVitepress light and dark mode images/figures](https://discourse.julialang.org/t/documentervitepress-light-and-dark-mode-images-figures/130477)

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**Author:** [@cneverett](https://discourse.julialang.org/u/cneverett)\
**Replies:** 0\
**Last updated:** [July 4, 2025, 7:03pm UTC](https://discourse.julialang.org/t/documentervitepress-light-and-dark-mode-images-figures/130477 "2025-07-04T19:03:16Z")

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Hello, I am using DocumenterVitepress.jl to generate some documentation for a package I am developing. I have generated both light and dark mode versions of figures (saved as png) that I would like to include in the doc…

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## [Repeated allocations for fft in pseudospectral code](https://discourse.julialang.org/t/repeated-allocations-for-fft-in-pseudospectral-code/130472)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [July 4, 2025, 4:37pm UTC](https://discourse.julialang.org/t/repeated-allocations-for-fft-in-pseudospectral-code/130472 "2025-07-04T16:37:44Z")

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I’m trying to tune a pseudospectral PDE code which has calls to fft and ifft at every iteration. I was wondering if there was some way to reduce the repeated memory allocations (assuming this improves performance). By …

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## [How far does type instability propagate?](https://discourse.julialang.org/t/how-far-does-type-instability-propagate/130350)

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**Author:** [@Leo\_I](https://discourse.julialang.org/u/Leo_I)\
**Replies:** 10\
**Last updated:** [July 4, 2025, 8:37am UTC](https://discourse.julialang.org/t/how-far-does-type-instability-propagate/130350 "2025-07-04T08:37:38Z")

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I have a function type\_uint(val::Integer) ::Type{\<:Unsigned} which returns the smallest UInt type that can still represent val without overflowing. I use this everywhere in my code, but only at top level. For example, g…

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## [Huge performance variance with \`if\` options in loops](https://discourse.julialang.org/t/huge-performance-variance-with-if-options-in-loops/130462)

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**Author:** [@hz-xiaxz](https://discourse.julialang.org/u/hz-xiaxz)\
**Replies:** 4\
**Last updated:** [July 4, 2025, 6:51am UTC](https://discourse.julialang.org/t/huge-performance-variance-with-if-options-in-loops/130462 "2025-07-04T06:51:35Z")

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I’m trying to optimize a non-allocating matrix update. Here is the simple code. function update\_W\_original!( W::AbstractMatrix, l::Int, K::Int, col\_cache::AbstractVector, row\_cache::AbstractVector, )…

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## [Order of Base.convert calls with \`@kwdef\` constructors](https://discourse.julialang.org/t/order-of-base-convert-calls-with-kwdef-constructors/130460)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 4\
**Last updated:** [July 4, 2025, 5:22am UTC](https://discourse.julialang.org/t/order-of-base-convert-calls-with-kwdef-constructors/130460 "2025-07-04T05:22:38Z")

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Base.convert( ::Type{Int64}, x::AbstractString ) = parse(Int64,x) @kwdef struct X a::Int64 b::Int64=a+1 end X(a="1") ERROR: MethodError: no method matching +(::String, ::Int64) Can I make the conversion pars…

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## [Package for dealing with symmetric matrices efficiently](https://discourse.julialang.org/t/package-for-dealing-with-symmetric-matrices-efficiently/130413)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 9\
**Last updated:** [July 4, 2025, 2:07am UTC](https://discourse.julialang.org/t/package-for-dealing-with-symmetric-matrices-efficiently/130413 "2025-07-04T02:07:16Z")

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The Julia Symmetric Matrix type stores the full matrix. I’m looking for a package that offers a way to store and to index into a symmetric matrix directly but only stores one triangle, but that is performant, operates a…

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## [NumPy is faster than Julia 1.11 for maximum function](https://discourse.julialang.org/t/numpy-is-faster-than-julia-1-11-for-maximum-function/130451)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 25\
**Last updated:** [July 4, 2025, 2:02am UTC](https://discourse.julialang.org/t/numpy-is-faster-than-julia-1-11-for-maximum-function/130451 "2025-07-04T02:02:57Z")

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import numpy as np A = np.rand(2026,51,251) # %timeit np.max(A) # 4.49 ms ± 89.2 μs per loop (mean ± std. dev. of 7 runs, 100 loops each) Julia code: using BenchmarkTools const A=rand(2026,51,251) @btime maximum(A) # …

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## [Dictionaries and such](https://discourse.julialang.org/t/dictionaries-and-such/130443)

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**Author:** [@skypuppy](https://discourse.julialang.org/u/skypuppy)\
**Replies:** 9\
**Last updated:** [July 3, 2025, 9:12pm UTC](https://discourse.julialang.org/t/dictionaries-and-such/130443 "2025-07-03T21:12:45Z")

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I hated using dictionaries in Python, mostly because they in-memory only. I guess I am so accustomed to relational DBMS’s that I just can’t think any other way. So, truly, are dictionaries that useful in Julia? Are th…

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## [In-place SciMLOperators](https://discourse.julialang.org/t/in-place-scimloperators/130457)

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**Author:** [@fdekerme](https://discourse.julialang.org/u/fdekerme)\
**Replies:** 0\
**Last updated:** [July 3, 2025, 5:19pm UTC](https://discourse.julialang.org/t/in-place-scimloperators/130457 "2025-07-03T17:19:02Z")

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Hello :grinning:, Can anyone tell me more about SciMLOperators.jl’s in-place operations? using SciMLOperators using BenchmarkTools function Afunc!(w,v,u,p,t) w\[1\] = -2v\[1\] + v\[2\] for i in 2:4 w\[i\] = v\[…

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## [Missing dylib , MacOS Sequoia, can't install 1.11](https://discourse.julialang.org/t/missing-dylib-macos-sequoia-cant-install-1-11/130416)

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**Author:** [@cellocgw](https://discourse.julialang.org/u/cellocgw)\
**Replies:** 9\
**Last updated:** [July 3, 2025, 12:19pm UTC](https://discourse.julialang.org/t/missing-dylib-macos-sequoia-cant-install-1-11/130416 "2025-07-03T12:19:12Z")

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Trying the “curl” command string, I get dyld\[33001\]: Library not loaded: /opt/local/lib/libssl.1.0.0.dylib Referenced from: \<2377B937-C59E-C708-1A33-0F668A90829B\> /opt/local/bin/curl Reason: tried: ‘/opt/local/lib/li…

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## [Negative false no longer acts as a strong zero](https://discourse.julialang.org/t/negative-false-no-longer-acts-as-a-strong-zero/128506)

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**Author:** [@lance\_xwq](https://discourse.julialang.org/u/lance_xwq)\
**Replies:** 23\
**Last updated:** [July 3, 2025, 11:06am UTC](https://discourse.julialang.org/t/negative-false-no-longer-acts-as-a-strong-zero/128506 "2025-07-03T11:06:19Z")

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Julia documentation states that false acts like a strong zero in multiplication, such that NaN \* false produces 0.0. However, Julia also defines -(x::Bool) = -Int(x), which seems to indicate -false is no longer a strong …

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## [Makie: manual colorbar tick values and tick labels](https://discourse.julialang.org/t/makie-manual-colorbar-tick-values-and-tick-labels/130437)

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**Author:** [@tduretz](https://discourse.julialang.org/u/tduretz)\
**Replies:** 1\
**Last updated:** [July 3, 2025, 8:25am UTC](https://discourse.julialang.org/t/makie-manual-colorbar-tick-values-and-tick-labels/130437 "2025-07-03T08:25:51Z")

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Hello, I was wondering how to set manual colorbar tick values and tick labels when using categorical colormap in Makie. I have prepared an MWE below. The data I want plot contain numeric values (1, 2, 3, 4) and NaN valu…

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## [Best-fit parameter error bar using Optimization.jl?](https://discourse.julialang.org/t/best-fit-parameter-error-bar-using-optimization-jl/103186)

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**Author:** [@abehersan](https://discourse.julialang.org/u/abehersan)\
**Replies:** 18\
**Last updated:** [July 2, 2025, 10:18pm UTC](https://discourse.julialang.org/t/best-fit-parameter-error-bar-using-optimization-jl/103186 "2025-07-02T22:18:01Z")

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Specifically in the context of local solvers with and without constraints. What is the standard way people report error bars on fitting parameters while using Optimization.jl? In principle this can be calculated if the…

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## [Ldiv for Cholesky is slower than two substitutions](https://discourse.julialang.org/t/ldiv-for-cholesky-is-slower-than-two-substitutions/130092)

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**Author:** [@stepanzh](https://discourse.julialang.org/u/stepanzh)\
**Replies:** 13\
**Last updated:** [July 2, 2025, 9:09pm UTC](https://discourse.julialang.org/t/ldiv-for-cholesky-is-slower-than-two-substitutions/130092 "2025-07-02T21:09:15Z")

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I’ve faced that ldiv for Cholesky is unexpectedly slower than two substitutions. Here is a test problem with a random 1000-by-1000 Matrix{Float64}. julia\> using BenchmarkTools, LinearAlgebra julia\> n = 1000; A = rand(…

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## [Mapping Linear Indices to Cartesian Indices](https://discourse.julialang.org/t/mapping-linear-indices-to-cartesian-indices/130424)

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**Author:** [@prconlin](https://discourse.julialang.org/u/prconlin)\
**Replies:** 5\
**Last updated:** [July 2, 2025, 8:40pm UTC](https://discourse.julialang.org/t/mapping-linear-indices-to-cartesian-indices/130424 "2025-07-02T20:40:32Z")

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Hello, I’m working with matrices in such a way that I want to be able to access values by both the Cartesian and linear Indices. I want to be able to map any given linear index to its Cartesian counterpart and vice ver…

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## [Julia version 1.10.9](https://discourse.julialang.org/t/julia-version-1-10-9/130428)

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**Author:** [@Smara\_Kazenango](https://discourse.julialang.org/u/Smara_Kazenango)\
**Replies:** 1\
**Last updated:** [July 2, 2025, 6:19pm UTC](https://discourse.julialang.org/t/julia-version-1-10-9/130428 "2025-07-02T18:19:49Z")

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I upgraded Julia from version 1.11.4 to version .9. I am receiving a kernel error when running Julia in Jupyter notebook. How can I fix this?

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## [Best practices for use of structs with NonlinearSolve.jl](https://discourse.julialang.org/t/best-practices-for-use-of-structs-with-nonlinearsolve-jl/130286)

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**Author:** [@PatrickMcFarlane](https://discourse.julialang.org/u/PatrickMcFarlane)\
**Replies:** 15\
**Last updated:** [July 2, 2025, 2:36pm UTC](https://discourse.julialang.org/t/best-practices-for-use-of-structs-with-nonlinearsolve-jl/130286 "2025-07-02T14:36:25Z")

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I’m working on an economic model where I need to solve a system of equations. Most of those equations are defined implicitly from a sort of mean-field game. Basically I construct several multidimensional arrays, const…

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## [Makie: How to convert keyword arguments in addition to positional arguments?](https://discourse.julialang.org/t/makie-how-to-convert-keyword-arguments-in-addition-to-positional-arguments/130405)

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**Author:** [@fverdugo](https://discourse.julialang.org/u/fverdugo)\
**Replies:** 5\
**Last updated:** [July 2, 2025, 2:31pm UTC](https://discourse.julialang.org/t/makie-how-to-convert-keyword-arguments-in-addition-to-positional-arguments/130405 "2025-07-02T14:31:06Z")

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Hi, When calling say Makie.mesh(args...;kwargs...) for some arguments with user defined-type, one can define an argument conversion for the positional arguments args using function Makie.convert\_arguments. But how to c…

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## [Mysterious gap on my GeoMakie plot](https://discourse.julialang.org/t/mysterious-gap-on-my-geomakie-plot/130367)

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**Author:** [@Leon6](https://discourse.julialang.org/u/Leon6)\
**Replies:** 3\
**Last updated:** [July 2, 2025, 1:50pm UTC](https://discourse.julialang.org/t/mysterious-gap-on-my-geomakie-plot/130367 "2025-07-02T13:50:37Z")

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Here is my code: File\_fig = joinpath(output\_path, "map.png"); isfile(File\_fig) && rm(File\_fig); using CairoMakie using GeoMakie lonbounds = (-180, -30); latbounds = (10, 80); Han = Figure(); ga = GeoAxis(Han\[1, 1\]; …

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## [Optimizing an objective function which contains auto-diifferentiation](https://discourse.julialang.org/t/optimizing-an-objective-function-which-contains-auto-diifferentiation/130395)

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**Author:** [@sn248](https://discourse.julialang.org/u/sn248)\
**Replies:** 3\
**Last updated:** [July 2, 2025, 12:22pm UTC](https://discourse.julialang.org/t/optimizing-an-objective-function-which-contains-auto-diifferentiation/130395 "2025-07-02T12:22:33Z")

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Hi I am trying to optimize an objective function which itself contains auto-differentiation, but the optimization fails, so I tried with a trivial example and it still fails. If anyone can suggest any approaches, that w…

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## [ReactiveECS vs Overseer: Reactive ECS is 4.6x faster than Overseer for 100k entities](https://discourse.julialang.org/t/reactiveecs-vs-overseer-reactive-ecs-is-4-6x-faster-than-overseer-for-100k-entities/130282)

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**Author:** [@Gesee](https://discourse.julialang.org/u/Gesee)\
**Replies:** 3\
**Last updated:** [July 2, 2025, 9:16am UTC](https://discourse.julialang.org/t/reactiveecs-vs-overseer-reactive-ecs-is-4-6x-faster-than-overseer-for-100k-entities/130282 "2025-07-02T09:16:44Z")

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Hello guys. I recently ran a comparison between ReactiveECS.jl (RECS) and Overseer.jl, two powerful ECS (Entity-Component-System) frameworks. The results are eye-opening and show that both frameworks have unique strengt…

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