# Latest

**URL:** https://discourse.julialang.org/latest.md?page=632

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

**Page:** 633

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## [Dash app precompilation](https://discourse.julialang.org/t/dash-app-precompilation/99529)

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**Author:** [@Maucejo](https://discourse.julialang.org/u/Maucejo)\
**Replies:** 2\
**Last updated:** [July 30, 2023, 3:26pm UTC](https://discourse.julialang.org/t/dash-app-precompilation/99529 "2023-07-30T15:26:27Z")

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Dear all, I have created a Dash application as a Julia module (say myApp.jl). This module has its own environment that I update from time to time. However, when I update the environment, the precompilation step of myApp…

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## [Symbolic (symmetric-toepltiz)matrix-vector multiplication doesn't work for higher dimensions of matrix](https://discourse.julialang.org/t/symbolic-symmetric-toepltiz-matrix-vector-multiplication-doesnt-work-for-higher-dimensions-of-matrix/102270)

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**Author:** [@yewalenikhil65](https://discourse.julialang.org/u/yewalenikhil65)\
**Replies:** 0\
**Last updated:** [July 30, 2023, 2:50pm UTC](https://discourse.julialang.org/t/symbolic-symmetric-toepltiz-matrix-vector-multiplication-doesnt-work-for-higher-dimensions-of-matrix/102270 "2023-07-30T14:50:07Z")

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I am trying following , and this works okay! using Symbolics, ToeplitzMatrices N =250 a = Symbolics.variables(:a, 0:N); b= \[1; (1:N).\*a\[2:end\]\] A = SymmetricToeplitz(a) F\_expr = A\*b; However, the code fails if i i…

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## [What could the Julia compiler learn from the LPython compiler?](https://discourse.julialang.org/t/what-could-the-julia-compiler-learn-from-the-lpython-compiler/102226)

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**Author:** [@xiaoxi](https://discourse.julialang.org/u/xiaoxi)\
**Replies:** 6\
**Last updated:** [July 30, 2023, 12:20pm UTC](https://discourse.julialang.org/t/what-could-the-julia-compiler-learn-from-the-lpython-compiler/102226 "2023-07-30T12:20:36Z")

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LPython is a Python compiler that can compile Python code with type annotations into optimized machine code, and offers Just-In-Time (JIT) compilation and seamless interoperability with CPython.

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## [Why do Julia functions handle keyword arguments as \`Base.Pairs\` instead of \`NamedTuple\` or \`Dict\`?](https://discourse.julialang.org/t/why-do-julia-functions-handle-keyword-arguments-as-base-pairs-instead-of-namedtuple-or-dict/102263)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 2\
**Last updated:** [July 30, 2023, 5:25am UTC](https://discourse.julialang.org/t/why-do-julia-functions-handle-keyword-arguments-as-base-pairs-instead-of-namedtuple-or-dict/102263 "2023-07-30T05:25:36Z")

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In Python, where we use \*args and \*\*kwargs to handle an arbitrary number of positional and keyword arguments in a function. In Python, these positional arguments are gathered into a tuple, and keyword arguments are gathe…

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## [How do I install dependencies from the \`\[extras\]\` block of Project.toml to the project-wide manifest?](https://discourse.julialang.org/t/how-do-i-install-dependencies-from-the-extras-block-of-project-toml-to-the-project-wide-manifest/102238)

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**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 3\
**Last updated:** [July 30, 2023, 4:05am UTC](https://discourse.julialang.org/t/how-do-i-install-dependencies-from-the-extras-block-of-project-toml-to-the-project-wide-manifest/102238 "2023-07-30T04:05:36Z")

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Many projects have a Project.toml that lists test dependencies in the \[extras\] block, following by a \[targets\] test = \[...\] block. This way, you can run julia --project in the base project directory and then \]test will…

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## [Write documentation PRs not blog posts](https://discourse.julialang.org/t/write-documentation-prs-not-blog-posts/100942)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 36\
**Last updated:** [July 30, 2023, 3:03am UTC](https://discourse.julialang.org/t/write-documentation-prs-not-blog-posts/100942 "2023-07-30T03:03:52Z")

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I will start by saying I have read many useful blog posts and course notes that have been linked on this forum, and I greatly appreciate the effort that goes into making them. The problem is they are not discoverable. It…

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## [Hard reset of Julia environment](https://discourse.julialang.org/t/hard-reset-of-julia-environment/102260)

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**Author:** [@mesonepigreco](https://discourse.julialang.org/u/mesonepigreco)\
**Replies:** 1\
**Last updated:** [July 29, 2023, 11:50pm UTC](https://discourse.julialang.org/t/hard-reset-of-julia-environment/102260 "2023-07-29T23:50:00Z")

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Hello, I need to reset a julia environment from all temporary files, like in a fresh installation after a mess I made that is causing many packages to fail precompiliation and loading. In particular, after I activate t…

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## [VS Code's built-in REPL does not seem to work with new contextual module repl under Julia 1.9](https://discourse.julialang.org/t/vs-codes-built-in-repl-does-not-seem-to-work-with-new-contextual-module-repl-under-julia-1-9/102256)

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**Author:** [@jinfreedom](https://discourse.julialang.org/u/jinfreedom)\
**Replies:** 1\
**Last updated:** [July 29, 2023, 10:44pm UTC](https://discourse.julialang.org/t/vs-codes-built-in-repl-does-not-seem-to-work-with-new-contextual-module-repl-under-julia-1-9/102256 "2023-07-29T22:44:05Z")

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VS Code’s built-in REPL, launched by alt-J alt-O, allows to execute code blocks from editor with shortcuts, thus quite useful in code development. Recent Julia 1.9 includes the very welcoming new feature of switching to …

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## [What does a function argument preceded by a colon do](https://discourse.julialang.org/t/what-does-a-function-argument-preceded-by-a-colon-do/102250)

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**Author:** [@2ton21](https://discourse.julialang.org/u/2ton21)\
**Replies:** 9\
**Last updated:** [July 29, 2023, 9:19pm UTC](https://discourse.julialang.org/t/what-does-a-function-argument-preceded-by-a-colon-do/102250 "2023-07-29T21:19:07Z")

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I have started to notice that some packages (like Makie and Plots) require passing arguments to functions that are preceded by a colon. For example, the Makie.jl basic tutorial https://docs.makie.org/stable/tutorials/ba…

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## [How to check if region made by one IntervalBox() contains a region made by another IntervalBox()?](https://discourse.julialang.org/t/how-to-check-if-region-made-by-one-intervalbox-contains-a-region-made-by-another-intervalbox/102246)

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**Author:** [@Ashu](https://discourse.julialang.org/u/Ashu)\
**Replies:** 1\
**Last updated:** [July 29, 2023, 8:48pm UTC](https://discourse.julialang.org/t/how-to-check-if-region-made-by-one-intervalbox-contains-a-region-made-by-another-intervalbox/102246 "2023-07-29T20:48:20Z")

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Hello, I want to check if Z = IntervalBox(-1..1, 4) lies in F = f(X...) where f(a, b, c, d) = \[a, b, c, d\] is a vector function, and X=IntervalBox(-10..10, 4) . Using IntervalArithmetic.jl package, I tried Z \\in F and Z…

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## [Jlrs v0.19: many performance optimizations](https://discourse.julialang.org/t/jlrs-v0-19-many-performance-optimizations/102253)

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**Author:** [@Taaitaaiger](https://discourse.julialang.org/u/Taaitaaiger)\
**Replies:** 0\
**Last updated:** [July 29, 2023, 8:43pm UTC](https://discourse.julialang.org/t/jlrs-v0-19-many-performance-optimizations/102253 "2023-07-29T20:43:33Z")

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jlrs is a crate for the Rust programming language that lets you embed Julia in Rust applications and export Rust functions and types to Julia. Version 0.19 puts a major focus on performance, which has led to the introduc…

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## [Diffractor release](https://discourse.julialang.org/t/diffractor-release/102123)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 30\
**Last updated:** [July 29, 2023, 8:37pm UTC](https://discourse.julialang.org/t/diffractor-release/102123 "2023-07-29T20:37:26Z")

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After many moons of waiting, we are finally ready to cut the first public release of Diffractor.jl (v0.2), our Next-generation Automatic Differentiation package. Due to its close coupling with the Julia compiler, it has …

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## [Broadcast implementation](https://discourse.julialang.org/t/broadcast-implementation/102249)

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**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 5\
**Last updated:** [July 29, 2023, 8:24pm UTC](https://discourse.julialang.org/t/broadcast-implementation/102249 "2023-07-29T20:24:23Z")

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Hello, good afternoon I have two data variables as below: data is a matrix 150x2 centroids is a matrix 3x2 Im trying to execute broadcast like in python, and get a vector x, y to get subtracted from all 150x2 observa…

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## [How does one create a GPU array from an Array](https://discourse.julialang.org/t/how-does-one-create-a-gpu-array-from-an-array/102247)

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**Author:** [@berk.geveci](https://discourse.julialang.org/u/berk.geveci)\
**Replies:** 1\
**Last updated:** [July 29, 2023, 6:42pm UTC](https://discourse.julialang.org/t/how-does-one-create-a-gpu-array-from-an-array/102247 "2023-07-29T18:42:07Z")

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Hi folks, I apologize for this basic question but I have not been able to resolve this by going through the documentation. How does one create a GPU array from an Array using KernelAbstractions? Similar to CuArray(array…

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## [Auto cxxwrap generator like autopybind11](https://discourse.julialang.org/t/auto-cxxwrap-generator-like-autopybind11/102225)

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**Author:** [@xgdgsc](https://discourse.julialang.org/u/xgdgsc)\
**Replies:** 3\
**Last updated:** [July 29, 2023, 6:21pm UTC](https://discourse.julialang.org/t/auto-cxxwrap-generator-like-autopybind11/102225 "2023-07-29T18:21:51Z")

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Is there something like autopybind11 / autopybind11 · GitLab where you define a simple config file and it generates all the code needed for wrapping for you?

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## [Type stable code with autodiff](https://discourse.julialang.org/t/type-stable-code-with-autodiff/102242)

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**Author:** [@mesonepigreco](https://discourse.julialang.org/u/mesonepigreco)\
**Replies:** 2\
**Last updated:** [July 29, 2023, 5:39pm UTC](https://discourse.julialang.org/t/type-stable-code-with-autodiff/102242 "2023-07-29T17:39:31Z")

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Dear Julia users I am writing a quite important julia project where performances are very important, and, to enforce type stability, almost all my functions look like this: function get\_kinetic\_energy(scha::SCHA{T}, en…

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## [What is regex for the end of string in Julia?](https://discourse.julialang.org/t/what-is-regex-for-the-end-of-string-in-julia/102228)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 7\
**Last updated:** [July 29, 2023, 4:29pm UTC](https://discourse.julialang.org/t/what-is-regex-for-the-end-of-string-in-julia/102228 "2023-07-29T16:29:33Z")

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What is regular expression for the final end of string in Julia?

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## [Is it possible to interpolate a value in a doctest output?](https://discourse.julialang.org/t/is-it-possible-to-interpolate-a-value-in-a-doctest-output/102244)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [July 29, 2023, 3:58pm UTC](https://discourse.julialang.org/t/is-it-possible-to-interpolate-a-value-in-a-doctest-output/102244 "2023-07-29T15:58:09Z")

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Suppose I have a doctest for a package where I define Chebyshev: \`\`\`jldoctest julia\> Chebyshev(0..1) Chebyshev(0..1) \`\`\` Say, my package depends on another package that defines the interval 0..1. Now, if the dependency…

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## [Solving a system of PDEs with MOL memory allocation problems](https://discourse.julialang.org/t/solving-a-system-of-pdes-with-mol-memory-allocation-problems/102199)

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**Author:** [@Hugo\_V](https://discourse.julialang.org/u/Hugo_V)\
**Replies:** 1\
**Last updated:** [July 29, 2023, 3:15pm UTC](https://discourse.julialang.org/t/solving-a-system-of-pdes-with-mol-memory-allocation-problems/102199 "2023-07-29T15:15:03Z")

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Hello, I´m new user of Julia and I´m trying to solve a system of PDES non lineal with method of lines. To check it I´m using a static solution not dependent on time. The idea is to recover to t\_i+1 the same solutions. I…

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## [ModelingToolkit.jl state-space representations -- what is the recommendation?](https://discourse.julialang.org/t/modelingtoolkit-jl-state-space-representations-what-is-the-recommendation/102212)

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**Author:** [@Andrew\_Liu](https://discourse.julialang.org/u/Andrew_Liu)\
**Replies:** 3\
**Last updated:** [July 29, 2023, 2:43pm UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-state-space-representations-what-is-the-recommendation/102212 "2023-07-29T14:43:52Z")

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What is the best way to represent a state space system in ModelingToolkit? For example @variables t x1(t) x2(t) u(t) y(t) @constants a11 = -1 a12 = 0.1a21 = 0 a22 = -1 b1 = 1 b2 = 0 c1 = 1 c2 = 1 D = Differential(t) eqs…

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## [What is regex for blank line in Julia?](https://discourse.julialang.org/t/what-is-regex-for-blank-line-in-julia/102230)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 3\
**Last updated:** [July 29, 2023, 2:15pm UTC](https://discourse.julialang.org/t/what-is-regex-for-blank-line-in-julia/102230 "2023-07-29T14:15:58Z")

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What is regular expression for Blank Line in Julia?

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## [JIT issues relevant to realtime applications](https://discourse.julialang.org/t/jit-issues-relevant-to-realtime-applications/67736)

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**Author:** [@solaris](https://discourse.julialang.org/u/solaris)\
**Replies:** 59\
**Last updated:** [July 29, 2023, 12:58pm UTC](https://discourse.julialang.org/t/jit-issues-relevant-to-realtime-applications/67736 "2023-07-29T12:58:06Z")

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First off, Julia’s performance (once JIT compiled) is insane! How?! (rhetorical). In my gaming development environment my naïve Julia code beats my naïve C++ code (clang O2 Release version). JIT is super useful for de…

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## [JuliaHub bug: package dependent not listed](https://discourse.julialang.org/t/juliahub-bug-package-dependent-not-listed/102229)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [July 29, 2023, 12:04pm UTC](https://discourse.julialang.org/t/juliahub-bug-package-dependent-not-listed/102229 "2023-07-29T12:04:50Z")

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The page for InfiniteLinearAlgebra lists InfiniteArrays as a dependency, but InfiniteArrays lists no dependents.

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## [Help me understand pipes - strange behavior](https://discourse.julialang.org/t/help-me-understand-pipes-strange-behavior/102224)

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**Author:** [@andromodon](https://discourse.julialang.org/u/andromodon)\
**Replies:** 6\
**Last updated:** [July 29, 2023, 9:44am UTC](https://discourse.julialang.org/t/help-me-understand-pipes-strange-behavior/102224 "2023-07-29T09:44:07Z")

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I’m running into something really strange for me in a pipeline. Can someone please explain why these two produce different results? julia\> "0X" |\> x -\> collect(UInt8, x) .|\> x -\> x == UInt8('X') ? UInt8(':') : x .|\> x -\>…

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## [Too much garbage collection for a simple vector addition operation](https://discourse.julialang.org/t/too-much-garbage-collection-for-a-simple-vector-addition-operation/102173)

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**Author:** [@ducanh-le](https://discourse.julialang.org/u/ducanh-le)\
**Replies:** 12\
**Last updated:** [July 29, 2023, 7:16am UTC](https://discourse.julialang.org/t/too-much-garbage-collection-for-a-simple-vector-addition-operation/102173 "2023-07-29T07:16:02Z")

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Hi everyone, I’m trying to optimize my code. When look at the profiler, the 2nd and the 3rd line below got GC flags: function resourceAvailable(v::Int32, a::Int32, usedResource::Vector{Int32}, md::ModelData) needed…

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## [How to show a floating point number without truncating, when the number can be expressed with a finite number of digits?](https://discourse.julialang.org/t/how-to-show-a-floating-point-number-without-truncating-when-the-number-can-be-expressed-with-a-finite-number-of-digits/102178)

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**Author:** [@archisman](https://discourse.julialang.org/u/archisman)\
**Replies:** 5\
**Last updated:** [July 29, 2023, 5:44am UTC](https://discourse.julialang.org/t/how-to-show-a-floating-point-number-without-truncating-when-the-number-can-be-expressed-with-a-finite-number-of-digits/102178 "2023-07-29T05:44:43Z")

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Today I attended the keynote talk by Stephen Wolfram in JuliaCon 2023, and he showed how Julia functions can be called inside Mathematica. He also showed an example where Julia evaluates 4^45 = 0. I figured out that 4.…

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## [ERROR: LoadError: type DataType has no field size](https://discourse.julialang.org/t/error-loaderror-type-datatype-has-no-field-size/102209)

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**Author:** [@ameersain](https://discourse.julialang.org/u/ameersain)\
**Replies:** 3\
**Last updated:** [July 29, 2023, 3:24am UTC](https://discourse.julialang.org/t/error-loaderror-type-datatype-has-no-field-size/102209 "2023-07-29T03:24:34Z")

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Hi. I am new to Julia and i am working on a project using Agents.jl. I installed the Agents package and it was working fine for a while but now when I try and do using Agents I get an error saying type DataType has no…

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## [Can I set --optimize flag when calling script](https://discourse.julialang.org/t/can-i-set-optimize-flag-when-calling-script/102217)

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**Author:** [@tomerarnon](https://discourse.julialang.org/u/tomerarnon)\
**Replies:** 3\
**Last updated:** [July 29, 2023, 1:43am UTC](https://discourse.julialang.org/t/can-i-set-optimize-flag-when-calling-script/102217 "2023-07-29T01:43:38Z")

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If I call a script with ./script.jl (crucially, not julia script.jl) can I still set the -O flag somehow? Passing it in after the file name doesn’t seem to work.

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## [JuliaCon 2023 - MRI Compressed Sensing and Denoising in Julia (MRICompress.jl) request to solve your sparse big data problem](https://discourse.julialang.org/t/juliacon-2023-mri-compressed-sensing-and-denoising-in-julia-mricompress-jl-request-to-solve-your-sparse-big-data-problem/102221)

<div class="topic-metadata">

**Author:** [@alexander-leong](https://discourse.julialang.org/u/alexander-leong)\
**Replies:** 0\
**Last updated:** [July 29, 2023, 1:35am UTC](https://discourse.julialang.org/t/juliacon-2023-mri-compressed-sensing-and-denoising-in-julia-mricompress-jl-request-to-solve-your-sparse-big-data-problem/102221 "2023-07-29T01:35:41Z")

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Hi everyone, MRICompress v0.0.1 is available for use alexander-leong/MRICompress.jl (github.com). For those that want to know more about what the package does you can view my JuliaCon talk at Alexander Leong on LinkedIn…

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## [How to implement the LayerNorm in NeuralPDE by Lux.jl](https://discourse.julialang.org/t/how-to-implement-the-layernorm-in-neuralpde-by-lux-jl/102120)

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**Author:** [@Ethan\_Tran](https://discourse.julialang.org/u/Ethan_Tran)\
**Replies:** 2\
**Last updated:** [July 28, 2023, 11:42pm UTC](https://discourse.julialang.org/t/how-to-implement-the-layernorm-in-neuralpde-by-lux-jl/102120 "2023-07-28T23:42:13Z")

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I tried to implement LayerNorm from Lux.jl package into NeuralPDE following a code: chain =\[Lux.Chain(Lux.LayerNorm(1,Lux.relu),Dense(1,10,Lux.tanh),Dense(10,20,Lux.tanh),Dense(20,10,Lux.tanh),Dense(10,1)) for \_ in 1:12…

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