# Latest

**URL:** https://discourse.julialang.org/latest.md?page=223

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

**Page:** 224

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## [How to copy the fields of a structure as new local variables?](https://discourse.julialang.org/t/how-to-copy-the-fields-of-a-structure-as-new-local-variables/125683)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 5\
**Last updated:** [February 8, 2025, 11:07am UTC](https://discourse.julialang.org/t/how-to-copy-the-fields-of-a-structure-as-new-local-variables/125683 "2025-02-08T11:07:37Z")

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Let’s say I have a loooong Parameters structure and a function where I want to refer simply with the parameter names rather than something like p.parameterx, how can I “automatically” copy the struct fields as local para…

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## [\`task\_local\_storage\`, why and where?](https://discourse.julialang.org/t/task-local-storage-why-and-where/125670)

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**Author:** [@Pedro](https://discourse.julialang.org/u/Pedro)\
**Replies:** 3\
**Last updated:** [February 8, 2025, 9:58am UTC](https://discourse.julialang.org/t/task-local-storage-why-and-where/125670 "2025-02-08T09:58:51Z")

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I recently discovered that there exists such function as task\_local\_storage for task. It’s exported. Can anyone give me an example of practical application of such functionality?

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## [Pluto and Bandits](https://discourse.julialang.org/t/pluto-and-bandits/125648)

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**Author:** [@Jose\_Ghislain\_Quenum](https://discourse.julialang.org/u/Jose_Ghislain_Quenum)\
**Replies:** 2\
**Last updated:** [February 8, 2025, 9:25am UTC](https://discourse.julialang.org/t/pluto-and-bandits/125648 "2025-02-08T09:25:33Z")

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Good day all, I have two quick questions. 1 - Is GitHub - rawls238/Bandits.jl: Implementation of multi-armed bandits in Julia the only implementation for the multi-armed bandits problem in Julia? 2- I am getting an error…

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## [Using BoundaryValueDiffEqFIRK: what is the format for solution derivative in bc! function?](https://discourse.julialang.org/t/using-boundaryvaluediffeqfirk-what-is-the-format-for-solution-derivative-in-bc-function/125600)

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**Author:** [@P0p5](https://discourse.julialang.org/u/P0p5)\
**Replies:** 5\
**Last updated:** [February 8, 2025, 8:09am UTC](https://discourse.julialang.org/t/using-boundaryvaluediffeqfirk-what-is-the-format-for-solution-derivative-in-bc-function/125600 "2025-02-08T08:09:33Z")

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I’m trying to use BVProblem with solver RadauIIa5. In the boundary condition function called by the solver, I need to refer to the first derivative of the solution. I can’t find an acceptable form for this derivative …

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## [Nonlinear System of Equations with Bounds/Constraints on Unknowns](https://discourse.julialang.org/t/nonlinear-system-of-equations-with-bounds-constraints-on-unknowns/37257)

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**Author:** [@bielim](https://discourse.julialang.org/u/bielim)\
**Replies:** 30\
**Last updated:** [February 8, 2025, 6:12am UTC](https://discourse.julialang.org/t/nonlinear-system-of-equations-with-bounds-constraints-on-unknowns/37257 "2025-02-08T06:12:25Z")

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I am trying to find a numerical solution to the following nonlinear system of equations: M\_1 - w\_1 θ\_1 α\_1 - w\_2 θ\_2 α\_2 = 0 M\_2 - w\_1 θ\_1^2 (α\_1+1) α\_1 - w\_2 θ\_2^2 (α\_2+1) α\_2 = 0 M\_3 - w\_1 θ\_1^3 (α\_1+2) (α\_1+1) α\_1 …

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## [Flux lines plot](https://discourse.julialang.org/t/flux-lines-plot/125619)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 13\
**Last updated:** [February 8, 2025, 1:17am UTC](https://discourse.julialang.org/t/flux-lines-plot/125619 "2025-02-08T01:17:36Z")

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We would like to produce an image similar to this one: except that what we have has nothing to do with climate. We have the density of a property on the surface of a sphere as a function of time. What are the tools …

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## [Launching the graphs community calls](https://discourse.julialang.org/t/launching-the-graphs-community-calls/103880)

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**Author:** [@gdalle](https://discourse.julialang.org/u/gdalle)\
**Replies:** 23\
**Last updated:** [February 7, 2025, 9:38pm UTC](https://discourse.julialang.org/t/launching-the-graphs-community-calls/103880 "2025-02-07T21:38:23Z")

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In an effort to strengthen the graphs ecosystem, and following the lead of other organizations, we are launching the graphs community calls :tada: Our first goal is that contributors get to know each other and agree on …

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## [Selection of Mosek Optimizer in JuMP not respected](https://discourse.julialang.org/t/selection-of-mosek-optimizer-in-jump-not-respected/125623)

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**Author:** [@saikrishna-nadella](https://discourse.julialang.org/u/saikrishna-nadella)\
**Replies:** 6\
**Last updated:** [February 7, 2025, 8:35pm UTC](https://discourse.julialang.org/t/selection-of-mosek-optimizer-in-jump-not-respected/125623 "2025-02-07T20:35:38Z")

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Hi, I am using MosekTools with JuMP. I have been facing problem in forcing solver attributes to Mosek. for example, following seems to work set\_attribute(myModel, “MSK\_IPAR\_PRESOLVE\_USE”, 0) but, following does not w…

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## [How to make a locally defined function type-stable?](https://discourse.julialang.org/t/how-to-make-a-locally-defined-function-type-stable/125639)

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**Author:** [@rkube](https://discourse.julialang.org/u/rkube)\
**Replies:** 7\
**Last updated:** [February 7, 2025, 7:26pm UTC](https://discourse.julialang.org/t/how-to-make-a-locally-defined-function-type-stable/125639 "2025-02-07T19:26:53Z")

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Hi, I’m wondering how and where I can add type annotations to make some code type-stable. I’m working with a structure: struct sensor{T} location normal α parameters id end The fields and locati…

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## [How to make splat, map and tuples be efficient](https://discourse.julialang.org/t/how-to-make-splat-map-and-tuples-be-efficient/125653)

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**Author:** [@garazha-ilya](https://discourse.julialang.org/u/garazha-ilya)\
**Replies:** 3\
**Last updated:** [February 7, 2025, 7:08pm UTC](https://discourse.julialang.org/t/how-to-make-splat-map-and-tuples-be-efficient/125653 "2025-02-07T19:08:29Z")

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Generally I want to make f(g("a"), g("c"), g("k")) with f(map(g, \["a","c","k"\])...) be efficient and don’t generate allocations. And I started experimenting, by creating 3 functions: function foo\_tuple(a,b,c) …

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## [Forward all function calls on ::MyType to another wrapped field](https://discourse.julialang.org/t/forward-all-function-calls-on-mytype-to-another-wrapped-field/105750)

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**Author:** [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)\
**Replies:** 20\
**Last updated:** [February 7, 2025, 6:51pm UTC](https://discourse.julialang.org/t/forward-all-function-calls-on-mytype-to-another-wrapped-field/105750 "2025-02-07T18:51:50Z")

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In Julia we cannot inherit from a concrete type. The advice often given to overcome this limitation is to use type composition, i.e. instead of making a type B a subtype of a concrete type A, wrap an instance of A in B,…

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## [What is the recommended way to use Mooncake.jl?](https://discourse.julialang.org/t/what-is-the-recommended-way-to-use-mooncake-jl/125663)

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**Author:** [@afleming](https://discourse.julialang.org/u/afleming)\
**Replies:** 1\
**Last updated:** [February 7, 2025, 5:18pm UTC](https://discourse.julialang.org/t/what-is-the-recommended-way-to-use-mooncake-jl/125663 "2025-02-07T17:18:54Z")

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See title. Should I use DifferentiationInterface? The existing (very excellent) documentation for Mooncake doesn’t offer much in the way of usage examples…

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## [Default linecolor name in Plots.jl?](https://discourse.julialang.org/t/default-linecolor-name-in-plots-jl/125634)

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**Author:** [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Replies:** 8\
**Last updated:** [February 7, 2025, 5:10pm UTC](https://discourse.julialang.org/t/default-linecolor-name-in-plots-jl/125634 "2025-02-07T17:10:39Z")

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Hello. I thought that the default linecolor for plotting lines in Plots.jl was :steelblue. But upon close examination, it seems to be different. It’s actually closer to :dodgerblue. Is there any julia function that retur…

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## [Documenter to github pages: build successful and pushed but page does not exist](https://discourse.julialang.org/t/documenter-to-github-pages-build-successful-and-pushed-but-page-does-not-exist/125183)

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**Author:** [@amaresh-sahu](https://discourse.julialang.org/u/amaresh-sahu)\
**Replies:** 1\
**Last updated:** [February 7, 2025, 4:13pm UTC](https://discourse.julialang.org/t/documenter-to-github-pages-build-successful-and-pushed-but-page-does-not-exist/125183 "2025-02-07T16:13:24Z")

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I am trying to push documentation for a package I wrote (currently not registered) to github pages. So far I: have the source code in a repo: GitHub - sahu-lab/MembraneAleFem.jl: source code for arbitrary Lagrangian--E…

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## [Add point coordinates to a GeoTable](https://discourse.julialang.org/t/add-point-coordinates-to-a-geotable/125126)

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**Author:** [@phchavesmaia](https://discourse.julialang.org/u/phchavesmaia)\
**Replies:** 12\
**Last updated:** [February 7, 2025, 3:05pm UTC](https://discourse.julialang.org/t/add-point-coordinates-to-a-geotable/125126 "2025-02-07T15:05:51Z")

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Hello everyone, I am trying to learn Julia and move some of my geostats projects to this language. I found that the GeoStats package is well regarded, hence I am using it. I have a grid and I want to separate the east f…

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## [Precompilation: Why does order matter when "using" packages for the first time?](https://discourse.julialang.org/t/precompilation-why-does-order-matter-when-using-packages-for-the-first-time/107056)

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**Author:** [@Tetrakai](https://discourse.julialang.org/u/Tetrakai)\
**Replies:** 26\
**Last updated:** [February 7, 2025, 2:03pm UTC](https://discourse.julialang.org/t/precompilation-why-does-order-matter-when-using-packages-for-the-first-time/107056 "2025-02-07T14:03:53Z")

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Last night, I was trying to get a Lux tutorial running. This was the order in the tutorial: using Lux, ComponentArrays, SciMLSensitivity, LuxAMDGPU, LuxCUDA, Optimisers, OrdinaryDiffEq, Random, Statistics, Zygote, OneHo…

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## [Difference between Tuple and NTuple](https://discourse.julialang.org/t/difference-between-tuple-and-ntuple/107357)

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**Author:** [@jiang\_ming\_zhang](https://discourse.julialang.org/u/jiang_ming_zhang)\
**Replies:** 2\
**Last updated:** [February 7, 2025, 2:14pm UTC](https://discourse.julialang.org/t/difference-between-tuple-and-ntuple/107357 "2025-02-07T14:14:21Z")

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Is ‘NTuple’ a more specific ‘Tuple’? It seems that in a Tuple, the elements can have different types, but in an NTuple, the elements must have the same type?

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## [Trying to build Julia documentation for v11.1.3 but Manifest says v11.1.1](https://discourse.julialang.org/t/trying-to-build-julia-documentation-for-v11-1-3-but-manifest-says-v11-1-1/125649)

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**Author:** [@Alexey\_Bogdanov](https://discourse.julialang.org/u/Alexey_Bogdanov)\
**Replies:** 3\
**Last updated:** [February 7, 2025, 12:34pm UTC](https://discourse.julialang.org/t/trying-to-build-julia-documentation-for-v11-1-3-but-manifest-says-v11-1-1/125649 "2025-02-07T12:34:12Z")

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Hi guys! I’m trying to build base html documentation for Julia v11.1.3 but in doc/Manifest.toml there is another version: v11.1.1 here and I think that is the reason of failing with such error: ERROR: LoadError: Unabl…

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## [Error "cannot enable executable stack" when starting Julia (solved)](https://discourse.julialang.org/t/error-cannot-enable-executable-stack-when-starting-julia-solved/125655)

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**Author:** [@marllos](https://discourse.julialang.org/u/marllos)\
**Replies:** 1\
**Last updated:** [February 7, 2025, 12:32pm UTC](https://discourse.julialang.org/t/error-cannot-enable-executable-stack-when-starting-julia-solved/125655 "2025-02-07T12:32:17Z")

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Recently, I encountered an unexpected issue when trying to run Julia on my Arch Linux. Everything had been working fine until suddenly Julia started failing with the following error: ERROR: Unable to load dependent libr…

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## [Stuck differentiating through multidimensional, potentially large and stiff ODE solution](https://discourse.julialang.org/t/stuck-differentiating-through-multidimensional-potentially-large-and-stiff-ode-solution/125651)

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**Author:** [@Vitor\_Patricio\_Canta](https://discourse.julialang.org/u/Vitor_Patricio_Canta)\
**Replies:** 0\
**Last updated:** [February 7, 2025, 11:52am UTC](https://discourse.julialang.org/t/stuck-differentiating-through-multidimensional-potentially-large-and-stiff-ode-solution/125651 "2025-02-07T11:52:36Z")

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Hi, I am solving 1D advective dispersive and reactive transport models as Ordinary Differential Equations. To speed things up, I am using Symbolics to detect the sparsity pattern or modelingtoolkitize to reduce allocati…

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## [Arc length for a spline](https://discourse.julialang.org/t/arc-length-for-a-spline/36161)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 27\
**Last updated:** [February 7, 2025, 8:04am UTC](https://discourse.julialang.org/t/arc-length-for-a-spline/36161 "2025-02-07T08:04:11Z")

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Given some spline (e.g. Dierckx.jl, Interpolations.jl), is there a good way to get its arc length? Right now I’m using this: using LinearAlgebra, Dierckx t = range(0, stop = π, length = 100) x = cos.(t) y = sin.(t) spl…

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## [How to debug the compiler with Debugger.jl](https://discourse.julialang.org/t/how-to-debug-the-compiler-with-debugger-jl/124229)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 1\
**Last updated:** [December 28, 2024, 1:19pm UTC](https://discourse.julialang.org/t/how-to-debug-the-compiler-with-debugger-jl/124229 "2024-12-28T13:19:15Z")

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For Debugger.jl, I assume compiled mode is enabled by default for @run? How do I disable it? I want to disable it to be able to step through the type inference code in the compiler. Can’t use VS Code’s debugger because i…

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## [JuMP & Ipopt: failed to converge solution for standard Rosenbrock](https://discourse.julialang.org/t/jump-ipopt-failed-to-converge-solution-for-standard-rosenbrock/125533)

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**Author:** [@GY3090](https://discourse.julialang.org/u/GY3090)\
**Replies:** 3\
**Last updated:** [February 7, 2025, 7:58am UTC](https://discourse.julialang.org/t/jump-ipopt-failed-to-converge-solution-for-standard-rosenbrock/125533 "2025-02-07T07:58:54Z")

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Hi everyone, I am new to Julia (and programming in general). I encountered an error while using JuMP and Ipopt to solve unconstrained maximization for a standard Rosenbrock function. It reports that “EXIT: Optimal Soluti…

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## [Sparse matrix of vectors](https://discourse.julialang.org/t/sparse-matrix-of-vectors/125636)

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**Author:** [@pulk\_jain](https://discourse.julialang.org/u/pulk_jain)\
**Replies:** 5\
**Last updated:** [February 6, 2025, 11:59pm UTC](https://discourse.julialang.org/t/sparse-matrix-of-vectors/125636 "2025-02-06T23:59:56Z")

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Hi, I wanted to store some information as a sparse matrix of vectors (or a tuple) to save on memory requirements. I am simulating a system of N(~50) particles in a box. If two particles contact then there are interactio…

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## [Cannot add ImageView package](https://discourse.julialang.org/t/cannot-add-imageview-package/125512)

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**Author:** [@dgagnon](https://discourse.julialang.org/u/dgagnon)\
**Replies:** 27\
**Last updated:** [February 6, 2025, 11:21pm UTC](https://discourse.julialang.org/t/cannot-add-imageview-package/125512 "2025-02-06T23:21:27Z")

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Hello I get a ton of warning while trying to install ImageView on Ubuntu 24.10 with Julia 1.11.3. At the end ImageView is not installed. julia\> Pkg.add("ImageView") Resolving package versions... No Changes to \`~/.…

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## [Receiving the Error: "MethodError: no method matching eps(::Int64)" When Using NonlinearProblem Solver](https://discourse.julialang.org/t/receiving-the-error-methoderror-no-method-matching-eps-int64-when-using-nonlinearproblem-solver/125514)

<div class="topic-metadata">

**Author:** [@mcket747](https://discourse.julialang.org/u/mcket747)\
**Replies:** 8\
**Last updated:** [February 6, 2025, 9:43pm UTC](https://discourse.julialang.org/t/receiving-the-error-methoderror-no-method-matching-eps-int64-when-using-nonlinearproblem-solver/125514 "2025-02-06T21:43:24Z")

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Hello, I am attempting to solve a non-linear optimization problem using the NonlinearProblem solver with the TrustRegion method. I kept getting the error saying there was no method for Float64(::ForwardDiff Dual etc). I …

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## [Initialization of DAE system after PDE discretization](https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633)

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**Author:** [@oswaldo](https://discourse.julialang.org/u/oswaldo)\
**Replies:** 1\
**Last updated:** [February 6, 2025, 9:29pm UTC](https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633 "2025-02-06T21:29:27Z")

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Hi, I’m solving a PDE system using ModelingToolkit.jl, after defining variables, parameters and equations I do @named adsmodel = PDESystem(eq,bcs,domains,\[z,t\],\[cN₂(z,t),cH₂(z,t),cNH₃(z,t),qNH₃(z,t),Tg(z,t),Tw(z,t),P(t)…

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## [Symbolics.jl - failing to simplify N-over-1 rational literals within expression](https://discourse.julialang.org/t/symbolics-jl-failing-to-simplify-n-over-1-rational-literals-within-expression/125446)

<div class="topic-metadata">

**Author:** [@jl\_enthusiast](https://discourse.julialang.org/u/jl_enthusiast)\
**Replies:** 4\
**Last updated:** [February 6, 2025, 9:28pm UTC](https://discourse.julialang.org/t/symbolics-jl-failing-to-simplify-n-over-1-rational-literals-within-expression/125446 "2025-02-06T21:28:54Z")

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Hi, I am currently trying to write some custom simplification rules throughout different stages of a symbolic manipulation process. One thing I noticed is that no matter how I try, I can’t come up with a rule that canc…

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## [Pretty print matrix a la display](https://discourse.julialang.org/t/pretty-print-matrix-a-la-display/125590)

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**Author:** [@Markos\_Kapes](https://discourse.julialang.org/u/Markos_Kapes)\
**Replies:** 6\
**Last updated:** [February 6, 2025, 7:01pm UTC](https://discourse.julialang.org/t/pretty-print-matrix-a-la-display/125590 "2025-02-06T19:01:20Z")

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if I have a matrix a = \[1 2; 3 4\] is there a way to get the string that display() pretty prints like so? 2×2 Matrix{Int64}: 1 2 3 4 I’m wondering because I want to be able to embed a depiction of the matrix in Plut…

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## [Using BoundaryValueDiffEqFIRK: How many boundary condition residual elements allowed?](https://discourse.julialang.org/t/using-boundaryvaluediffeqfirk-how-many-boundary-condition-residual-elements-allowed/125602)

<div class="topic-metadata">

**Author:** [@P0p5](https://discourse.julialang.org/u/P0p5)\
**Replies:** 5\
**Last updated:** [February 6, 2025, 6:51pm UTC](https://discourse.julialang.org/t/using-boundaryvaluediffeqfirk-how-many-boundary-condition-residual-elements-allowed/125602 "2025-02-06T18:51:37Z")

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Again, I’m trying to use BVProblem with solver RadauIIa5. In the boundary condition function called by the solver, what is the maximum length of the residual vector, which is the first argument of this function? I am …

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