# Latest

**URL:** https://discourse.julialang.org/latest.md?page=267

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

**Page:** 268

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## [Package to compute Hessian matrix numerically](https://discourse.julialang.org/t/package-to-compute-hessian-matrix-numerically/123151)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 2\
**Last updated:** [November 27, 2024, 1:23pm UTC](https://discourse.julialang.org/t/package-to-compute-hessian-matrix-numerically/123151 "2024-11-27T13:23:55Z")

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Given numerical zᵢⱼ values defined over a regular 2D grid (xᵢⱼ, yᵢⱼ), is there a package to compute the Hessian matrix at each grid point?

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## [Advantages of Julia vs Mojo](https://discourse.julialang.org/t/advantages-of-julia-vs-mojo/111614)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 26\
**Last updated:** [April 20, 2024, 1:33am UTC](https://discourse.julialang.org/t/advantages-of-julia-vs-mojo/111614 "2024-04-20T01:33:38Z")

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Tomorrow I have a presentation concerning my package, but questions about Julia will surely arrive and likely about Mojo. I haven’t tried it, to those who did it (recently), what do you think are the user cases where Ju…

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## [Please help me to understand the \`OhMyThreads.jl\` parallel mutation example](https://discourse.julialang.org/t/please-help-me-to-understand-the-ohmythreads-jl-parallel-mutation-example/123114)

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**Author:** [@scheidan1](https://discourse.julialang.org/u/scheidan1)\
**Replies:** 8\
**Last updated:** [November 27, 2024, 11:17am UTC](https://discourse.julialang.org/t/please-help-me-to-understand-the-ohmythreads-jl-parallel-mutation-example/123114 "2024-11-27T11:17:55Z")

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Hi all, The documentation of OhMyThreads.jl contains an example of an apparently very simple parallelization: # Base.Threads using Base.Threads: @threads data = rand(10) @threads for i in eachindex(data) data\[i\] =…

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## [Building Docker image on a machine and deploying on another invalidates precompile cache](https://discourse.julialang.org/t/building-docker-image-on-a-machine-and-deploying-on-another-invalidates-precompile-cache/123086)

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**Author:** [@Pere](https://discourse.julialang.org/u/Pere)\
**Replies:** 3\
**Last updated:** [November 27, 2024, 11:07am UTC](https://discourse.julialang.org/t/building-docker-image-on-a-machine-and-deploying-on-another-invalidates-precompile-cache/123086 "2024-11-27T11:07:11Z")

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I’m building a Docker image with a precompile statement in its Dockerfile to make startup faster. If I deploy the image on the same machine where it was built, it starts up very quick. However, If I deploy to a differen…

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## [Unexpected behavior of package loading in workers using Distributed](https://discourse.julialang.org/t/unexpected-behavior-of-package-loading-in-workers-using-distributed/122814)

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**Author:** [@HanD](https://discourse.julialang.org/u/HanD)\
**Replies:** 7\
**Last updated:** [November 27, 2024, 10:32am UTC](https://discourse.julialang.org/t/unexpected-behavior-of-package-loading-in-workers-using-distributed/122814 "2024-11-27T10:32:55Z")

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The following phenomenon gave me quite a headache and took me a while to track down. Take the following example (using Julia 1.11.1 or 1.10.6, probably older ones as well): julia\> using Distributed, Statistics julia\> a…

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## [Why \`Mojo\` can be so fast?](https://discourse.julialang.org/t/why-mojo-can-be-so-fast/98458)

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**Author:** [@Brian1](https://discourse.julialang.org/u/Brian1)\
**Replies:** 14\
**Last updated:** [May 15, 2023, 1:45pm UTC](https://discourse.julialang.org/t/why-mojo-can-be-so-fast/98458 "2023-05-15T13:45:33Z")

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Mojo is a new language, this is the introduction of it. I am curious about its performance, so I made a test for it. In the Jupyter supplied by the Mojo: %%python import time def fib(n): if n == 0 or n == 1: …

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## [Create ForwardDiff.Dual is slow](https://discourse.julialang.org/t/create-forwarddiff-dual-is-slow/123093)

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**Author:** [@shady287](https://discourse.julialang.org/u/shady287)\
**Replies:** 5\
**Last updated:** [November 26, 2024, 6:13pm UTC](https://discourse.julialang.org/t/create-forwarddiff-dual-is-slow/123093 "2024-11-26T18:13:17Z")

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Hi all, I am using ForwardDiff to calculate a jacobian in a physical problem. Everything works and I am happy with the results. Now I would like to optimaze it but I am failing in doing so. As a start, I have a very la…

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## [Type instability clarification](https://discourse.julialang.org/t/type-instability-clarification/123118)

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**Author:** [@s\_amap](https://discourse.julialang.org/u/s_amap)\
**Replies:** 6\
**Last updated:** [November 27, 2024, 8:47am UTC](https://discourse.julialang.org/t/type-instability-clarification/123118 "2024-11-27T08:47:57Z")

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Hi. I’m currently investigating performance and type stability matters relating to a package (and learning along the way). Here’s one type stability issue I don’t understand regarding a parametric type used in a variab…

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## [What function is called to convert a type to a string as part of string interpolation?](https://discourse.julialang.org/t/what-function-is-called-to-convert-a-type-to-a-string-as-part-of-string-interpolation/123119)

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**Author:** [@world-peace](https://discourse.julialang.org/u/world-peace)\
**Replies:** 7\
**Last updated:** [November 27, 2024, 7:59am UTC](https://discourse.julialang.org/t/what-function-is-called-to-convert-a-type-to-a-string-as-part-of-string-interpolation/123119 "2024-11-27T07:59:13Z")

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I’m currently using the following code example\_string = "$(logdata.level)" to convert from a Base.CoreLogging.LogLevel to a String. However I would guess that there is a function call which can be used instead to do t…

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## [Pkg.add(“DiffEqOperators”) throws error](https://discourse.julialang.org/t/pkg-add-diffeqoperators-throws-error/123081)

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**Author:** [@Y1123929](https://discourse.julialang.org/u/Y1123929)\
**Replies:** 2\
**Last updated:** [November 27, 2024, 3:42am UTC](https://discourse.julialang.org/t/pkg-add-diffeqoperators-throws-error/123081 "2024-11-27T03:42:23Z")

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I’m getting an error using Pkg.add(“DiffEqOperators”) How this situation should be resolved. I would be grateful. Pkg.add("DiffEqOperators") Resolving package versions... ERROR: Unsatisfiable requirements detected f…

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## [Julia v1.10.7 has been released](https://discourse.julialang.org/t/julia-v1-10-7-has-been-released/123141)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 0\
**Last updated:** [November 27, 2024, 3:26am UTC](https://discourse.julialang.org/t/julia-v1-10-7-has-been-released/123141 "2024-11-27T03:26:18Z")

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Julia version 1.10.7, the seventh patch release in the 1.10 long-term support (LTS) series of releases, is now available. Binaries are available via JuliaUp and at https://julialang.org/downloads/ for macOS (Intel and M-…

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## [Is it possible to enforce scheduler to instantly yield to specific task?](https://discourse.julialang.org/t/is-it-possible-to-enforce-scheduler-to-instantly-yield-to-specific-task/123133)

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**Author:** [@Pedro](https://discourse.julialang.org/u/Pedro)\
**Replies:** 0\
**Last updated:** [November 27, 2024, 12:13am UTC](https://discourse.julialang.org/t/is-it-possible-to-enforce-scheduler-to-instantly-yield-to-specific-task/123133 "2024-11-27T00:13:27Z")

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I writing a program with the aim of real-time and low-latency data processing that have multiple tasks running on a single thread. For two of those tasks, let’s call them A and B, I need a very tight synchronization on s…

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## [Symbolics.jl rewrite rule](https://discourse.julialang.org/t/symbolics-jl-rewrite-rule/105041)

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**Author:** [@Ian\_L](https://discourse.julialang.org/u/Ian_L)\
**Replies:** 2\
**Last updated:** [November 26, 2024, 10:55pm UTC](https://discourse.julialang.org/t/symbolics-jl-rewrite-rule/105041 "2024-11-26T22:55:38Z")

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I defined the following rule: rlogexp = @rule log(exp(~x)) =\> ~x This seems to work for simple expressions: \> simplify(log(exp(x+3)), rewriter=rlogexp) 3+x However, this doesn’t seem to simplify \> simplify(log(exp(…

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## [Symbolics.jl and predicates for pattern matching](https://discourse.julialang.org/t/symbolics-jl-and-predicates-for-pattern-matching/85202)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 10:42pm UTC](https://discourse.julialang.org/t/symbolics-jl-and-predicates-for-pattern-matching/85202 "2024-11-26T22:42:57Z")

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I’m trying to translate some patterns written in Mathematica to Symbolics.jl to explore the latter package. I’m interested in conditions (e.g. type constraints) imposed on patterns. This is handled by “predicates” in Sym…

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## [Function findall and overlapping](https://discourse.julialang.org/t/function-findall-and-overlapping/123126)

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**Author:** [@Colin\_Beckingham](https://discourse.julialang.org/u/Colin_Beckingham)\
**Replies:** 3\
**Last updated:** [November 26, 2024, 9:42pm UTC](https://discourse.julialang.org/t/function-findall-and-overlapping/123126 "2024-11-26T21:42:00Z")

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When I use the code findall("DD","DDDAADDD") I get the response 2-element Vector{UnitRange{Int64}}: 1:2 6:7 But perhaps the answer might include the others, such as 2:3 and 7:8? What am I missing here? The function…

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## [Help Needed: S3 Connection Error with MinIO in Development Environment](https://discourse.julialang.org/t/help-needed-s3-connection-error-with-minio-in-development-environment/122957)

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**Author:** [@OgmaJ](https://discourse.julialang.org/u/OgmaJ)\
**Replies:** 9\
**Last updated:** [November 26, 2024, 9:16pm UTC](https://discourse.julialang.org/t/help-needed-s3-connection-error-with-minio-in-development-environment/122957 "2024-11-26T21:16:02Z")

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Hello community, I’m trying to connect to a MinIO instance (an S3-compatible provider) in my development environment using Julia and the AWS and AWSS3 packages. I’ve written a script to list buckets, but I’m encounterin…

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## [Global sensitivity analysis in a large parameter space - computational cost](https://discourse.julialang.org/t/global-sensitivity-analysis-in-a-large-parameter-space-computational-cost/93598)

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**Author:** [@Nick1](https://discourse.julialang.org/u/Nick1)\
**Replies:** 15\
**Last updated:** [November 26, 2024, 9:05pm UTC](https://discourse.julialang.org/t/global-sensitivity-analysis-in-a-large-parameter-space-computational-cost/93598 "2024-11-26T21:05:06Z")

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Hi everyone, I have been working in a large biochemical reaction network and I try to perform Global sensitivity analysis (GSA) (see my last post). I was wondering if there are any advice, or suggestions regarding the e…

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## [TU Delft Off-Campus Student Teaching Position Available](https://discourse.julialang.org/t/tu-delft-off-campus-student-teaching-position-available/119291)

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**Author:** [@Domenico\_Lahaye](https://discourse.julialang.org/u/Domenico_Lahaye)\
**Replies:** 3\
**Last updated:** [November 26, 2024, 8:35pm UTC](https://discourse.julialang.org/t/tu-delft-off-campus-student-teaching-position-available/119291 "2024-11-26T20:35:35Z")

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I am looking to hire a master student (100 hundred hours) with interest to expand the project described at Project description. Please apply by replying here. Thanks!

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## [AxisKeys diplay issue in Pluto](https://discourse.julialang.org/t/axiskeys-diplay-issue-in-pluto/123121)

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**Author:** [@cdawg](https://discourse.julialang.org/u/cdawg)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 7:56pm UTC](https://discourse.julialang.org/t/axiskeys-diplay-issue-in-pluto/123121 "2024-11-26T19:56:48Z")

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For some reason, the beautiful display of KeyedArray in Pluto uses the fallback method and simply shows the keyedArray as a collected iterator or something. In the terminal: In Pluto Can someone help me fix or re…

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## [How to copy variables from one optimized JuMP model into another model?](https://discourse.julialang.org/t/how-to-copy-variables-from-one-optimized-jump-model-into-another-model/123103)

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**Author:** [@Realife\_Brahmin](https://discourse.julialang.org/u/Realife_Brahmin)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 6:44pm UTC](https://discourse.julialang.org/t/how-to-copy-variables-from-one-optimized-jump-model-into-another-model/123103 "2024-11-26T18:44:20Z")

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Hello everyone, I’m working on a multi-period optimization problem using Julia, JuMP, and Ipopt. My approach involves solving individual time-step optimization subproblems as separate JuMP models (sub\_model\_t0), then in…

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## [Help with nested ForwardDiff.jl calculation](https://discourse.julialang.org/t/help-with-nested-forwarddiff-jl-calculation/123077)

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**Author:** [@longemen3000](https://discourse.julialang.org/u/longemen3000)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 5:51pm UTC](https://discourse.julialang.org/t/help-with-nested-forwarddiff-jl-calculation/123077 "2024-11-26T17:51:00Z")

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i’m trying to solve a non linear system of equations via newton’s method. the problem is along the lines of: f(model::Nothing,a,x) = sum(x)\*a + log(a/sum(x)) function g(model::Nothing,a,x) = ForwardDiff.gradient(z-\> f(m…

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## [State Dependent Mass Matrix](https://discourse.julialang.org/t/state-dependent-mass-matrix/40238)

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**Author:** [@321bwa](https://discourse.julialang.org/u/321bwa)\
**Replies:** 9\
**Last updated:** [November 26, 2024, 5:52pm UTC](https://discourse.julialang.org/t/state-dependent-mass-matrix/40238 "2024-11-26T17:52:29Z")

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Hello, I’ve looked at the documentation for Handling Mass Matrices for DifferentialEquations.jl. In the example was a singular matrix. I would like to know how to implement a state dependent mass matrix, where the matri…

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## [Gaussian Curvature calculation](https://discourse.julialang.org/t/gaussian-curvature-calculation/30037)

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**Author:** [@Ameba\_Brain](https://discourse.julialang.org/u/Ameba_Brain)\
**Replies:** 8\
**Last updated:** [November 26, 2024, 5:06pm UTC](https://discourse.julialang.org/t/gaussian-curvature-calculation/30037 "2024-11-26T17:06:18Z")

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Dear all, Please advise in which module can I find implementation of Gaussian Curvature of a surface? Something similar to the MATLAB function: Surface Curvature - File Exchange - MATLAB Central Thank you in advance

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## [Define empty array with sizehint in single step](https://discourse.julialang.org/t/define-empty-array-with-sizehint-in-single-step/123082)

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**Author:** [@hexaeder](https://discourse.julialang.org/u/hexaeder)\
**Replies:** 6\
**Last updated:** [November 26, 2024, 3:12pm UTC](https://discourse.julialang.org/t/define-empty-array-with-sizehint-in-single-step/123082 "2024-11-26T15:12:34Z")

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Is there a stdlib function to generate an empty array of a given type with a specific sizehint at construction time? Sometimes, push! based filling of arrays is just easier to write and read, even if you know exactly ho…

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## [Resolve using local package and local\_julia\_registry](https://discourse.julialang.org/t/resolve-using-local-package-and-local-julia-registry/123062)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 3\
**Last updated:** [November 26, 2024, 2:56pm UTC](https://discourse.julialang.org/t/resolve-using-local-package-and-local-julia-registry/123062 "2024-11-26T14:56:19Z")

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I have a Windows computer which is working fine and a Raspberry PI 4 with 8 Gig memory on Raspberry PI OS, a Debian derivative. On the Raspberry PI git always asks for a user name and password, where the password is the…

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## [Enzyme Autodiff readonly error and working with batches of data](https://discourse.julialang.org/t/enzyme-autodiff-readonly-error-and-working-with-batches-of-data/123012)

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**Author:** [@turiya](https://discourse.julialang.org/u/turiya)\
**Replies:** 14\
**Last updated:** [November 26, 2024, 2:28pm UTC](https://discourse.julialang.org/t/enzyme-autodiff-readonly-error-and-working-with-batches-of-data/123012 "2024-11-26T14:28:35Z")

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I have the following MWE using Enzyme, Lux, Random n = 10 x\_batch = randn(2,n) y\_batch = randn(2,n) model = Chain(Parallel(vcat, Dense(2, 1, tanh), Dense(2,1,tanh)), Dense(2,1,tanh)) rng = Random.default\_rng() Random.se…

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## [Julia Programming Language on Bluesky](https://discourse.julialang.org/t/julia-programming-language-on-bluesky/123054)

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**Author:** [@rayegun](https://discourse.julialang.org/u/rayegun)\
**Replies:** 30\
**Last updated:** [November 26, 2024, 2:23pm UTC](https://discourse.julialang.org/t/julia-programming-language-on-bluesky/123054 "2024-11-26T14:23:12Z")

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We have a new social media account for the Julia Programming Language! Follow us for release news, JuliaCon updates, package announcements, community events, and other social media fun! We look forward to building a …

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## [Using ForwardDiff for Symbolic.derivative() definition](https://discourse.julialang.org/t/using-forwarddiff-for-symbolic-derivative-definition/123035)

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**Author:** [@anodos](https://discourse.julialang.org/u/anodos)\
**Replies:** 7\
**Last updated:** [November 26, 2024, 12:49pm UTC](https://discourse.julialang.org/t/using-forwarddiff-for-symbolic-derivative-definition/123035 "2024-11-26T12:49:20Z")

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I’ve only been playing with MTK.jl for a day or two, but I’m really impressed - the workflow here is so much nicer than using a dedicated acausal modelling language! I’m running into situations where judicious function r…

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## [Function specialization based on values, not just types](https://discourse.julialang.org/t/function-specialization-based-on-values-not-just-types/123043)

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**Author:** [@benc](https://discourse.julialang.org/u/benc)\
**Replies:** 18\
**Last updated:** [November 26, 2024, 12:42pm UTC](https://discourse.julialang.org/t/function-specialization-based-on-values-not-just-types/123043 "2024-11-26T12:42:38Z")

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I’m working on Markov Chains where a lot of recursive functions have a mathematical parametric equation with a base case, simplified to function f(xs, 1) @info "Base case" end function f(xs, val) @info "Gene…

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## [How to interpret this function with no name, and two sets of parenthesis](https://discourse.julialang.org/t/how-to-interpret-this-function-with-no-name-and-two-sets-of-parenthesis/123092)

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**Author:** [@world-peace](https://discourse.julialang.org/u/world-peace)\
**Replies:** 3\
**Last updated:** [November 26, 2024, 12:40pm UTC](https://discourse.julialang.org/t/how-to-interpret-this-function-with-no-name-and-two-sets-of-parenthesis/123092 "2024-11-26T12:40:43Z")

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Can anyone help me understand how to interpret the below function? It appears to be an anonymous function, but has two sets of parenthesis. function (j::JSON)(io, args) (io, args) are arguments to this function. But w…

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