# Latest

**URL:** https://discourse.julialang.org/latest.md?page=151

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

**Page:** 152

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## [Evaluate a local variable by name](https://discourse.julialang.org/t/evaluate-a-local-variable-by-name/129846)

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**Author:** [@goerz](https://discourse.julialang.org/u/goerz)\
**Replies:** 4\
**Last updated:** [June 13, 2025, 8:34am UTC](https://discourse.julialang.org/t/evaluate-a-local-variable-by-name/129846 "2025-06-13T08:34:40Z")

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Is there a particularly elegant way to eval a local variable? My use case would be this function: function A\_dipole(which, x, y, z; A₀=19.8517061694#=ų MHz=#) i, j = (Symbol(\_) for \_ in String(which)) r = √(x^2 + y^2…

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## [Performance discrepancy for different ways of piping/composing functions for handling runtime dispatch](https://discourse.julialang.org/t/performance-discrepancy-for-different-ways-of-piping-composing-functions-for-handling-runtime-dispatch/129773)

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**Author:** [@frankwswang](https://discourse.julialang.org/u/frankwswang)\
**Replies:** 9\
**Last updated:** [June 13, 2025, 4:30am UTC](https://discourse.julialang.org/t/performance-discrepancy-for-different-ways-of-piping-composing-functions-for-handling-runtime-dispatch/129773 "2025-06-13T04:30:29Z")

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MWE (tested on Julia 1.11.5): julia\> foo1(::Val{N}) where {N} = N foo1 (generic function with 1 method) julia\> foo2(n::Int) = Val(n) foo2 (generic function with 1 method) julia\> a = Val.(rand(Int, 1000)); julia\> usin…

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## [Speed of \`hasmethod\` with and without kwargs](https://discourse.julialang.org/t/speed-of-hasmethod-with-and-without-kwargs/129847)

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**Author:** [@mmkrusniak](https://discourse.julialang.org/u/mmkrusniak)\
**Replies:** 3\
**Last updated:** [June 12, 2025, 11:53pm UTC](https://discourse.julialang.org/t/speed-of-hasmethod-with-and-without-kwargs/129847 "2025-06-12T23:53:28Z")

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I’m a novice at writing high-performance code with Julia (1.11). I have an unknown function from a user, and I want to check if it accepts any of several possible sets of keyword names. But for reasons unknown to me, ha…

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## [Timeout / early kill an external process](https://discourse.julialang.org/t/timeout-early-kill-an-external-process/53876)

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**Author:** [@s-baumann](https://discourse.julialang.org/u/s-baumann)\
**Replies:** 3\
**Last updated:** [June 12, 2025, 10:27pm UTC](https://discourse.julialang.org/t/timeout-early-kill-an-external-process/53876 "2025-06-12T22:27:19Z")

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I want to do a terminal command (on linux) with a timeout. I know there is not a timeout built into the run command so I was trying to do something to make one. So basically I tried: function run\_with\_timeout(command::S…

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## [Mug.jl performance drop-off](https://discourse.julialang.org/t/mug-jl-performance-drop-off/129841)

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**Author:** [@Roger\_Powell](https://discourse.julialang.org/u/Roger_Powell)\
**Replies:** 2\
**Last updated:** [June 12, 2025, 8:58pm UTC](https://discourse.julialang.org/t/mug-jl-performance-drop-off/129841 "2025-06-12T20:58:30Z")

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I love Julia but I am struggling with the Mug.jl interface. When I first downloaded it, the code coverage (aka white glaze) was pretty complete, but now I notice that it’s dropped back to about 70% and soon “Julia” will …

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## [PReLU with long compilation time](https://discourse.julialang.org/t/prelu-with-long-compilation-time/129783)

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**Author:** [@cirobr](https://discourse.julialang.org/u/cirobr)\
**Replies:** 1\
**Last updated:** [June 12, 2025, 6:24pm UTC](https://discourse.julialang.org/t/prelu-with-long-compilation-time/129783 "2025-06-12T18:24:35Z")

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Cheers, I have implemented a PReLU nonlinearity that seems to be working quite well in my models, except for the fact the model’s compilation time (\*) is way longer than the equivalent model with ReLU instead. Given my…

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## [Somewhere somehow Julia caches the path to Python, and I do not understand why](https://discourse.julialang.org/t/somewhere-somehow-julia-caches-the-path-to-python-and-i-do-not-understand-why/129814)

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**Author:** [@dmitry-kabanov](https://discourse.julialang.org/u/dmitry-kabanov)\
**Replies:** 13\
**Last updated:** [June 12, 2025, 4:42pm UTC](https://discourse.julialang.org/t/somewhere-somehow-julia-caches-the-path-to-python-and-i-do-not-understand-why/129814 "2025-06-12T16:42:45Z")

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How, I ran into some strange behavior with Julia. I have a software package that works like this Julia user code starts (via dlopen) a C library that instantiates an embedded Python Python user code does the same Eve…

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## [\[ANN\] Announcing PSSFSS: Polarization and Frequency Selective Surfaces](https://discourse.julialang.org/t/ann-announcing-pssfss-polarization-and-frequency-selective-surfaces/61331)

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**Author:** [@PeterSimon](https://discourse.julialang.org/u/PeterSimon)\
**Replies:** 4\
**Last updated:** [June 12, 2025, 3:45pm UTC](https://discourse.julialang.org/t/ann-announcing-pssfss-polarization-and-frequency-selective-surfaces/61331 "2025-06-12T15:45:36Z")

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I’m excited to announce a new package PSSFSS.jl for analyzing polarization selective surfaces (PSSs), frequency selective surfaces (FSSs), reflectarray elements, radomes, and similar structures. It is intended to be u…

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## [LowLevelParticleFilters compatibility with ComponentArrays](https://discourse.julialang.org/t/lowlevelparticlefilters-compatibility-with-componentarrays/129830)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 4\
**Last updated:** [June 12, 2025, 2:51pm UTC](https://discourse.julialang.org/t/lowlevelparticlefilters-compatibility-with-componentarrays/129830 "2025-06-12T14:51:37Z")

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I’m developing a Kalman Filter for a system that is made up of many components. Since the model is somewhat big I was hoping to use a ComponentArray to extract individual system (and subsystem) states from the state vec…

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## [Python & Julia Environment Setup](https://discourse.julialang.org/t/python-julia-environment-setup/129837)

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**Author:** [@GA-Brady](https://discourse.julialang.org/u/GA-Brady)\
**Replies:** 0\
**Last updated:** [June 12, 2025, 2:26pm UTC](https://discourse.julialang.org/t/python-julia-environment-setup/129837 "2025-06-12T14:26:11Z")

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I’m building a data analysis pipeline using Julia. However, there are some Python3 specific packages that I need. The python packages automatically output files, which I intend to access via Julia. I am aware that tool…

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## [Eigen produces non-normalized eigenvectors](https://discourse.julialang.org/t/eigen-produces-non-normalized-eigenvectors/129829)

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**Author:** [@nvenkov1](https://discourse.julialang.org/u/nvenkov1)\
**Replies:** 5\
**Last updated:** [June 12, 2025, 11:58am UTC](https://discourse.julialang.org/t/eigen-produces-non-normalized-eigenvectors/129829 "2025-06-12T11:58:48Z")

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I realized that, when using LinearAlgebra.jl’s eigen function to solve a general eigenvalue problem for a matrix pencil (A, B), the eigenvectors returned do not seem to be normalized in any way. The standard in the numer…

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## [DifferentialEquations.jl: Malloc errors in ODEProblems](https://discourse.julialang.org/t/differentialequations-jl-malloc-errors-in-odeproblems/129684)

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**Author:** [@k-ray-liu](https://discourse.julialang.org/u/k-ray-liu)\
**Replies:** 6\
**Last updated:** [June 12, 2025, 10:59am UTC](https://discourse.julialang.org/t/differentialequations-jl-malloc-errors-in-odeproblems/129684 "2025-06-12T10:59:30Z")

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Hi there, I’m having memory related problem when running the solver for ODEProblems, with the DifferentialEquations.jl package. It’s very inconsistent when the problem will arise (I’m scanning across a large number of …

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## [Speeding up combination of Funs](https://discourse.julialang.org/t/speeding-up-combination-of-funs/129400)

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**Author:** [@nilsbecker](https://discourse.julialang.org/u/nilsbecker)\
**Replies:** 15\
**Last updated:** [June 11, 2025, 1:28pm UTC](https://discourse.julialang.org/t/speeding-up-combination-of-funs/129400 "2025-06-11T13:28:48Z")

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I’m building up an ApproxFun.Fun by successively multiplying a lot of individual factors along a graph. The individual factors are themselves also Funs. The situation is similar to this fake code factors = \[\] for n in …

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## [UndefVarError for closure defined in a function](https://discourse.julialang.org/t/undefvarerror-for-closure-defined-in-a-function/129809)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 6\
**Last updated:** [June 12, 2025, 10:48am UTC](https://discourse.julialang.org/t/undefvarerror-for-closure-defined-in-a-function/129809 "2025-06-12T10:48:31Z")

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Hi all. I’m working on an EM algorithm which will necessarily call many optimization solves (using Optim.jl). That means that I’ll need to optimize various functions while holding other values constant. The obvious way t…

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## [How to replace backslash](https://discourse.julialang.org/t/how-to-replace-backslash/129816)

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**Author:** [@gvanuxem](https://discourse.julialang.org/u/gvanuxem)\
**Replies:** 2\
**Last updated:** [June 12, 2025, 10:01am UTC](https://discourse.julialang.org/t/how-to-replace-backslash/129816 "2025-06-12T10:01:51Z")

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Hello, For example, this one does not work: julia\> replace("foo \\spadbar{jjjd}","\\\\spad"=\>"") ERROR: ParseError: # Error @ REPL\[6\]:1:21 ulia\> replace("foo \\spadbar{jjjd}","\\\\spad"=\>"") # └┘ ── inval…

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## [Engineering formatting with SI prefixes using Formatting.jl](https://discourse.julialang.org/t/engineering-formatting-with-si-prefixes-using-formatting-jl/103107)

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**Author:** [@owiecc](https://discourse.julialang.org/u/owiecc)\
**Replies:** 3\
**Last updated:** [June 12, 2025, 7:55am UTC](https://discourse.julialang.org/t/engineering-formatting-with-si-prefixes-using-formatting-jl/103107 "2025-06-12T07:55:15Z")

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I am trying to use pretty formatting engineering with Formatting.jl but I fail. Is it possible to automatically format numbers with SI prefixes and, ideally, be able to select precision? E.g.: 0.01 → 10m 0.022 → 22m …

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## [I want help about combination problem](https://discourse.julialang.org/t/i-want-help-about-combination-problem/129821)

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**Author:** [@nunf](https://discourse.julialang.org/u/nunf)\
**Replies:** 5\
**Last updated:** [June 12, 2025, 7:48am UTC](https://discourse.julialang.org/t/i-want-help-about-combination-problem/129821 "2025-06-12T07:48:27Z")

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I have array of 1-38 I want to choose 11 of them, so it will have 1203322288 possibility. and I want to do some calculation on all combination. If I loop one by one through all combination It will take very long time. …

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## [Any recommended resources for using Julia in Computer Vision?](https://discourse.julialang.org/t/any-recommended-resources-for-using-julia-in-computer-vision/129812)

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**Author:** [@AI\_hayasaka](https://discourse.julialang.org/u/AI_hayasaka)\
**Replies:** 1\
**Last updated:** [June 12, 2025, 6:14am UTC](https://discourse.julialang.org/t/any-recommended-resources-for-using-julia-in-computer-vision/129812 "2025-06-12T06:14:23Z")

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I am looking for some good resources (books, videos, courses, etc…) for using Julia in computer vision domain. Especially with respect to, Object Detection, Image Classification, etc..

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## [A toy example triggering Gurobi's Warning: Model contains variables with very large bounds participating in product terms](https://discourse.julialang.org/t/a-toy-example-triggering-gurobis-warning-model-contains-variables-with-very-large-bounds-participating-in-product-terms/127295)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 13\
**Last updated:** [June 11, 2025, 7:32pm UTC](https://discourse.julialang.org/t/a-toy-example-triggering-gurobis-warning-model-contains-variables-with-very-large-bounds-participating-in-product-terms/127295 "2025-06-11T19:32:30Z")

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It’s common to find Gurobi logging the following Warning in QCP Warning: Model contains variables with very large bounds participating in product terms. Presolve was not able to compute smaller bounds for these variabl…

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## [Flux error](https://discourse.julialang.org/t/flux-error/129818)

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**Author:** [@Smara\_Kazenango](https://discourse.julialang.org/u/Smara_Kazenango)\
**Replies:** 1\
**Last updated:** [June 11, 2025, 8:43pm UTC](https://discourse.julialang.org/t/flux-error/129818 "2025-06-11T20:43:19Z")

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using Flux.Data: DataLoader I am getting error that Data is not defined?

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## [Pkg.add("PyPlot" or Pkg.build("PyCall") not working](https://discourse.julialang.org/t/pkg-add-pyplot-or-pkg-build-pycall-not-working/129800)

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**Author:** [@Smara\_Kazenango](https://discourse.julialang.org/u/Smara_Kazenango)\
**Replies:** 14\
**Last updated:** [June 11, 2025, 7:22pm UTC](https://discourse.julialang.org/t/pkg-add-pyplot-or-pkg-build-pycall-not-working/129800 "2025-06-11T19:22:04Z")

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I have tried Pkg.add(“PyPlot”) or Pkg.build(“PyCall”) and both are not working and producing errors. Does anyone know how I can fix this to run my script?

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## [\`DifferentialEquations.jl\` and \`KrylovKit.jl\` not playing nice together](https://discourse.julialang.org/t/differentialequations-jl-and-krylovkit-jl-not-playing-nice-together/129811)

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**Author:** [@NitinGupta](https://discourse.julialang.org/u/NitinGupta)\
**Replies:** 4\
**Last updated:** [June 11, 2025, 4:13pm UTC](https://discourse.julialang.org/t/differentialequations-jl-and-krylovkit-jl-not-playing-nice-together/129811 "2025-06-11T16:13:55Z")

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I cannot get the above-mentioned two packages to work together. If I have one of them installed, the other one does not install (apparently an issue with LinearSolve and DiffEqArrayOperator. I tested this to be the case…

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## [Cannot solve sylvester equation with sparse matrix](https://discourse.julialang.org/t/cannot-solve-sylvester-equation-with-sparse-matrix/129787)

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**Author:** [@Giorgos\_Vretinaris](https://discourse.julialang.org/u/Giorgos_Vretinaris)\
**Replies:** 3\
**Last updated:** [June 11, 2025, 4:02pm UTC](https://discourse.julialang.org/t/cannot-solve-sylvester-equation-with-sparse-matrix/129787 "2025-06-11T16:02:47Z")

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Hello, I have a peculiar situation where I am trying to solve AX + XB = C but A is sparse, for example think of A as a differential operator. But, this isn’t allowed, I have a small working example here: begin A = …

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## [ParametricOptInterface + Clarabel](https://discourse.julialang.org/t/parametricoptinterface-clarabel/129745)

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**Author:** [@klamike](https://discourse.julialang.org/u/klamike)\
**Replies:** 5\
**Last updated:** [June 11, 2025, 2:25pm UTC](https://discourse.julialang.org/t/parametricoptinterface-clarabel/129745 "2025-06-11T14:25:46Z")

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I am trying to use POI with Clarabel. Based on the ParametricOptInterface.jl readme, the recommended usage is with direct\_model. Here, I’ve just swapped HiGHS.jl for Clarabel.jl: using JuMP, Clarabel import ParametricOp…

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## [Julia (AcceleratedKernels) vs JAX time comparison](https://discourse.julialang.org/t/julia-acceleratedkernels-vs-jax-time-comparison/129781)

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**Author:** [@mcp](https://discourse.julialang.org/u/mcp)\
**Replies:** 21\
**Last updated:** [June 11, 2025, 1:54pm UTC](https://discourse.julialang.org/t/julia-acceleratedkernels-vs-jax-time-comparison/129781 "2025-06-11T13:54:33Z")

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Hi everyone! Following this topic, I’d like to understand how to write an efficient CPU/GPU agnostic code using AcceleratedKernels.jl. My problem is writing the joint PDF of two random variables, one of which is condit…

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## [How to check if a dataframe column exists](https://discourse.julialang.org/t/how-to-check-if-a-dataframe-column-exists/129802)

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**Author:** [@Ju\_ska](https://discourse.julialang.org/u/Ju_ska)\
**Replies:** 5\
**Last updated:** [June 11, 2025, 1:54pm UTC](https://discourse.julialang.org/t/how-to-check-if-a-dataframe-column-exists/129802 "2025-06-11T13:54:07Z")

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Hi, how to properly check if a column is present in a dataframe ? E.g. verify col1, col3. using DataFrames df = DataFrame(col1 = \[1, 2\], col2 = \[2, 1\])

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## [OpenSSL\_jll error after PyCall-importing a module which uses libcrypto](https://discourse.julialang.org/t/openssl-jll-error-after-pycall-importing-a-module-which-uses-libcrypto/129806)

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**Author:** [@polhager](https://discourse.julialang.org/u/polhager)\
**Replies:** 0\
**Last updated:** [June 11, 2025, 1:53pm UTC](https://discourse.julialang.org/t/openssl-jll-error-after-pycall-importing-a-module-which-uses-libcrypto/129806 "2025-06-11T13:53:15Z")

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So OpenSSL\_jll uses libcrypto and libssl, both of which are downloaded as artifacts. libssl has a dependency on libcrypto, so when loading libssl the system also looks for libcrypto. During normal usage, everything works…

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## [Array and clocked signal](https://discourse.julialang.org/t/array-and-clocked-signal/129778)

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**Author:** [@yjr](https://discourse.julialang.org/u/yjr)\
**Replies:** 2\
**Last updated:** [June 11, 2025, 1:26pm UTC](https://discourse.julialang.org/t/array-and-clocked-signal/129778 "2025-06-11T13:26:54Z")

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Hello, I m basically trying to implement a PRBS or similar signal generator using vector and discrete clock signal. But it does not seem that both can be handled simultaenously. Am I right or is there a way to use both …

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## [Histogram equalization with OpenCV](https://discourse.julialang.org/t/histogram-equalization-with-opencv/126421)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 2\
**Last updated:** [June 11, 2025, 11:42am UTC](https://discourse.julialang.org/t/histogram-equalization-with-opencv/126421 "2025-06-11T11:42:13Z")

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I am using OpenCV.jl for image processing and I want to increase the contrast of an image using adaptive histogram equalization. I can create the CLAHE object with OpenCV.createCLAHE, but that is an “C++ smart pointer of…

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## [Native Julia FID (Fréchet Inception Distance) Computation](https://discourse.julialang.org/t/native-julia-fid-frechet-inception-distance-computation/129798)

<div class="topic-metadata">

**Author:** [@josemanuel22](https://discourse.julialang.org/u/josemanuel22)\
**Replies:** 0\
**Last updated:** [June 11, 2025, 10:00am UTC](https://discourse.julialang.org/t/native-julia-fid-frechet-inception-distance-computation/129798 "2025-06-11T10:00:18Z")

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Is there a relatively simple way to calculate the FID (Fréchet Inception Distance) metric in Julia? Metalhead doesn’t include a pre-trained Inception-v3 model. I know you can try ONNX or PythonCall (though all of those h…

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