# Latest

**URL:** https://discourse.julialang.org/latest.md?page=971

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

**Page:** 972

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## [What is harder about saving a Julia session via the REPL whenever?](https://discourse.julialang.org/t/what-is-harder-about-saving-a-julia-session-via-the-repl-whenever/82897)

<div class="topic-metadata">

**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 10\
**Last updated:** [July 26, 2022, 3:05am UTC](https://discourse.julialang.org/t/what-is-harder-about-saving-a-julia-session-via-the-repl-whenever/82897 "2022-07-26T03:05:13Z")

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I’m learning PackageCompiler.jl, and I’m wondering why creating a sysimage requires an input of packages, the project/environment, and precompile scripts. I do appreciate the paper trail, but couldn’t a sysimage be creat…

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## [Strange Memory Allocations with DifferentialEquations](https://discourse.julialang.org/t/strange-memory-allocations-with-differentialequations/83909)

<div class="topic-metadata">

**Author:** [@7vn](https://discourse.julialang.org/u/7vn)\
**Replies:** 3\
**Last updated:** [July 26, 2022, 2:33am UTC](https://discourse.julialang.org/t/strange-memory-allocations-with-differentialequations/83909 "2022-07-26T02:33:58Z")

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Hello, I’m observing very strange and large memory allocations while solving a standard ODE and evaluating it at given times. However, after the first benchmark, if (and only if!) I recompile the integrated function the…

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## [Call for contribution to a Julia version of HEP Software Foundation Tutorials](https://discourse.julialang.org/t/call-for-contribution-to-a-julia-version-of-hep-software-foundation-tutorials/84784)

<div class="topic-metadata">

**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 0\
**Last updated:** [July 26, 2022, 2:31am UTC](https://discourse.julialang.org/t/call-for-contribution-to-a-julia-version-of-hep-software-foundation-tutorials/84784 "2022-07-26T02:31:17Z")

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The goal is to provide similar tutorials as listed at: HSF Software Training Center Currently we have covered the uproot tutorial (lacking detail commentary atm) I have started a repo with setup CI + Pluto static build…

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## [How can I save surrogate model in Julia and use it in Python](https://discourse.julialang.org/t/how-can-i-save-surrogate-model-in-julia-and-use-it-in-python/84746)

<div class="topic-metadata">

**Author:** [@Jack\_Tang](https://discourse.julialang.org/u/Jack_Tang)\
**Replies:** 4\
**Last updated:** [July 26, 2022, 2:29am UTC](https://discourse.julialang.org/t/how-can-i-save-surrogate-model-in-julia-and-use-it-in-python/84746 "2022-07-26T02:29:09Z")

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Hello, In my project, I would like to save surrogate model in Julia and use it in Python. HDF5 is the best file format? If yes, How can I read the surrogate model and use it in Python? Thanks!

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## [Julia 1.6 other libcurl download issues](https://discourse.julialang.org/t/julia-1-6-other-libcurl-download-issues/59738)

<div class="topic-metadata">

**Author:** [@neophytedave](https://discourse.julialang.org/u/neophytedave)\
**Replies:** 23\
**Last updated:** [July 26, 2022, 2:20am UTC](https://discourse.julialang.org/t/julia-1-6-other-libcurl-download-issues/59738 "2022-07-26T02:20:28Z")

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I long ago abandoned working with Julia (Windows 10). I have not been able to add any packages at all for the last several versions. I get the following messages. (@v1.6) pkg\> add Plots Updating registry at \`C:\\Us…

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## [JuliaHub registration fails: Could not fetch associated GitHub/GitLab account](https://discourse.julialang.org/t/juliahub-registration-fails-could-not-fetch-associated-github-gitlab-account/65353)

<div class="topic-metadata">

**Author:** [@MartinOtter](https://discourse.julialang.org/u/MartinOtter)\
**Replies:** 5\
**Last updated:** [July 25, 2022, 8:35pm UTC](https://discourse.julialang.org/t/juliahub-registration-fails-could-not-fetch-associated-github-gitlab-account/65353 "2022-07-25T20:35:25Z")

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I tried to register new versions of my packages in Juliahub, such as https://github.com/ModiaSim/ModiaPlot\_GLMakie.jl. When clicking the Submit button, I get the error message: Could not fetch associated GitHub/GitLab a…

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## [Any packages for Point Cloud Registration](https://discourse.julialang.org/t/any-packages-for-point-cloud-registration/54679)

<div class="topic-metadata">

**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 8:23pm UTC](https://discourse.julialang.org/t/any-packages-for-point-cloud-registration/54679 "2022-07-25T20:23:02Z")

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I’m currently looking for a library that can solve or assist solving the following problem. I have a bunch of 3D point clouds from different angles and would like to combine them to have a single 3d point cloud. Seems l…

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## [How to gain access variables as soons as they are assigned a value?](https://discourse.julialang.org/t/how-to-gain-access-variables-as-soons-as-they-are-assigned-a-value/84747)

<div class="topic-metadata">

**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 5\
**Last updated:** [July 25, 2022, 7:55pm UTC](https://discourse.julialang.org/t/how-to-gain-access-variables-as-soons-as-they-are-assigned-a-value/84747 "2022-07-25T19:55:47Z")

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I was wondering whether in JuMP is possible to be aware of the value of variables while the model is still running?? I mean, suppose we have a set of binary variables x(i,j) i,j in \[1,2,3,...,n\]. Is there any possiblit…

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## [Run the half-life of code analysis on Julia?](https://discourse.julialang.org/t/run-the-half-life-of-code-analysis-on-julia/763)

<div class="topic-metadata">

**Author:** [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Replies:** 11\
**Last updated:** [July 25, 2022, 7:22pm UTC](https://discourse.julialang.org/t/run-the-half-life-of-code-analysis-on-julia/763 "2022-07-25T19:22:28Z")

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Not quite a language development post (so maybe it will get recategorized), but it would be interesting to see the results of this “half-life of code” analysis on Julia’s git repo: I thought the results would be inter…

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## [Potentially Getting Started With DifferentialEquations.jl](https://discourse.julialang.org/t/potentially-getting-started-with-differentialequations-jl/84772)

<div class="topic-metadata">

**Author:** [@yoshi](https://discourse.julialang.org/u/yoshi)\
**Replies:** 1\
**Last updated:** [July 25, 2022, 7:05pm UTC](https://discourse.julialang.org/t/potentially-getting-started-with-differentialequations-jl/84772 "2022-07-25T19:05:49Z")

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I’m trying to assess whether Julia can be used for my use case. I have a ~25 dimensional differential equation whose solutions I’d to analyze for a variety of initial conditions and choices of parameters. As such, I have…

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## [Time for JET.jl first run?](https://discourse.julialang.org/t/time-for-jet-jl-first-run/75827)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 7:03pm UTC](https://discourse.julialang.org/t/time-for-jet-jl-first-run/75827 "2022-07-25T19:03:12Z")

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I just updated to Julia v1.7.1 and added Jet.jl to my project environment. I put together a file like this # contents of jet\_test.jl using MyPackage const problem\_size = 2^7 function main(problem\_size) tmp = MyFun…

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## [Understanding Pkg - add a temporary development module](https://discourse.julialang.org/t/understanding-pkg-add-a-temporary-development-module/84762)

<div class="topic-metadata">

**Author:** [@hros](https://discourse.julialang.org/u/hros)\
**Replies:** 2\
**Last updated:** [July 25, 2022, 6:43pm UTC](https://discourse.julialang.org/t/understanding-pkg-add-a-temporary-development-module/84762 "2022-07-25T18:43:59Z")

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A recent workshop (on MLJ) began with the following instructions for adding a module for the workshop: ENV\["JULIA\_PKG\_PRECOMPILE\_AUTO"\]=0 using Pkg Pkg.activate(temp=true) Pkg.develop(url="https://github.com/ablaom/Hell…

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## [GUI package for a "real-time" control application](https://discourse.julialang.org/t/gui-package-for-a-real-time-control-application/84673)

<div class="topic-metadata">

**Author:** [@Hawkes](https://discourse.julialang.org/u/Hawkes)\
**Replies:** 30\
**Last updated:** [July 25, 2022, 6:01pm UTC](https://discourse.julialang.org/t/gui-package-for-a-real-time-control-application/84673 "2022-07-25T18:01:23Z")

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Hi, since some time I’m wondering how to (i.e. using which GUI library) to build a GUI-based control/measurement application using Julia. In the past I have used Python + PyQt + PyQtGraph to create quite performant GUIs…

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## [Strange regex error (bug?)](https://discourse.julialang.org/t/strange-regex-error-bug/84759)

<div class="topic-metadata">

**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 6:00pm UTC](https://discourse.julialang.org/t/strange-regex-error-bug/84759 "2022-07-25T18:00:03Z")

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julia\> r"^\\s\*text" r"^\\s\*text" julia\> Regex("^\\s\*text") ERROR: syntax: invalid escape sequence Julia 1.7.3 on Win10 And BTW what does the following error message mean? julia\> r"^\[:space:\]\*text" ERROR: LoadError: PCRE…

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## [Convert Array{UInt8, 3} to Matrix{RGB{N0f8}}](https://discourse.julialang.org/t/convert-array-uint8-3-to-matrix-rgb-n0f8/84767)

<div class="topic-metadata">

**Author:** [@Alon\_Ben-Arieh](https://discourse.julialang.org/u/Alon_Ben-Arieh)\
**Replies:** 1\
**Last updated:** [July 25, 2022, 5:26pm UTC](https://discourse.julialang.org/t/convert-array-uint8-3-to-matrix-rgb-n0f8/84767 "2022-07-25T17:26:49Z")

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Hi all I have a NumPy array, representing an image, I send from a python module to a Julia function. The NumPy array is received in the Julia function as Array{UInt8, 3}. I need to convert it to Matrix{RGB{N0f8}}. How…

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## [Using CellListMap.jl within Agents.jl framework](https://discourse.julialang.org/t/using-celllistmap-jl-within-agents-jl-framework/84709)

<div class="topic-metadata">

**Author:** [@ehsani63](https://discourse.julialang.org/u/ehsani63)\
**Replies:** 15\
**Last updated:** [July 25, 2022, 5:26pm UTC](https://discourse.julialang.org/t/using-celllistmap-jl-within-agents-jl-framework/84709 "2022-07-25T17:26:02Z")

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Hi, I am using CellListMap in one of my ABM simulations (using Agents.jl). It suits very well what I want to do: There some active agents and some static obstacles. CellListMap finds collisions between agents and obstacl…

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## [Converting a PyCall numpy ×3 Array{UInt8, 3} to RGB](https://discourse.julialang.org/t/converting-a-pycall-numpy-x3-array-uint8-3-to-rgb/70537)

<div class="topic-metadata">

**Author:** [@Pytrator](https://discourse.julialang.org/u/Pytrator)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 5:26pm UTC](https://discourse.julialang.org/t/converting-a-pycall-numpy-x3-array-uint8-3-to-rgb/70537 "2022-07-25T17:26:01Z")

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Hey guys, I use the NumPy per PyCall to get screenshots of my desktop. I get these images back as 1440×3440×3 Array{UInt8, 3} Discord user borodi#9175 already shared a function of him that converts this array to a BGR. …

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## [How to launch Julia from a customized script in Vscode](https://discourse.julialang.org/t/how-to-launch-julia-from-a-customized-script-in-vscode/84742)

<div class="topic-metadata">

**Author:** [@Weijie](https://discourse.julialang.org/u/Weijie)\
**Replies:** 5\
**Last updated:** [July 25, 2022, 2:57pm UTC](https://discourse.julialang.org/t/how-to-launch-julia-from-a-customized-script-in-vscode/84742 "2022-07-25T14:57:51Z")

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Dear there, These days I was trying to launch Julia from a script (in my customized path) that defines the JULIA\_DEPOT\_PATH and Executable\_Path in Vscode. However, it seems that the julia\_extension is not able to find t…

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## [Possible bug with \\ operator](https://discourse.julialang.org/t/possible-bug-with-operator/84753)

<div class="topic-metadata">

**Author:** [@AnshPatel7](https://discourse.julialang.org/u/AnshPatel7)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 2:57pm UTC](https://discourse.julialang.org/t/possible-bug-with-operator/84753 "2022-07-25T14:57:28Z")

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I’m using the \\ operator to solve the linear system Ax=b in the general case, even when A is singular. This invariably throws up the SingularException(2). But in the documentation, it is clearly stated that it should giv…

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## [Why do I have to specify the name of the module when code is included in remote processes?](https://discourse.julialang.org/t/why-do-i-have-to-specify-the-name-of-the-module-when-code-is-included-in-remote-processes/84756)

<div class="topic-metadata">

**Author:** [@zekeriya.sari](https://discourse.julialang.org/u/zekeriya.sari)\
**Replies:** 0\
**Last updated:** [July 25, 2022, 1:57pm UTC](https://discourse.julialang.org/t/why-do-i-have-to-specify-the-name-of-the-module-when-code-is-included-in-remote-processes/84756 "2022-07-25T13:57:08Z")

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Hi Consider the following two files test.jl and temp.jl with the following content # test.jl file module Foo using Distributed function baz() addprocs(2) @everywhere include("temp.jl") for worker in work…

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## [Gaussian Elimination Function that is Fast](https://discourse.julialang.org/t/gaussian-elimination-function-that-is-fast/84714)

<div class="topic-metadata">

**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 6\
**Last updated:** [July 25, 2022, 12:14pm UTC](https://discourse.julialang.org/t/gaussian-elimination-function-that-is-fast/84714 "2022-07-25T12:14:28Z")

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I was testing this package from this repository, it is faster than A \\ b I do not know any other competitor for calculating Gaussian Elimination that can be measured with @time. If anyone knows, I would like to know an…

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## [How to generate a reusable static LLVM IR module?](https://discourse.julialang.org/t/how-to-generate-a-reusable-static-llvm-ir-module/83226)

<div class="topic-metadata">

**Author:** [@knlv.ok](https://discourse.julialang.org/u/knlv.ok)\
**Replies:** 4\
**Last updated:** [July 25, 2022, 11:44am UTC](https://discourse.julialang.org/t/how-to-generate-a-reusable-static-llvm-ir-module/83226 "2022-07-25T11:44:21Z")

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Hello, I am a beginner in Julia programming. I need a way to generate a static LLVM IR module for functions written in Julia and modify the LLVM IR that was generated. I saw on CUDAnative.jl , there are some features …

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## [Fast way of selecting rows in DataFrames / csv-file with primary keys](https://discourse.julialang.org/t/fast-way-of-selecting-rows-in-dataframes-csv-file-with-primary-keys/84535)

<div class="topic-metadata">

**Author:** [@pjuergens](https://discourse.julialang.org/u/pjuergens)\
**Replies:** 4\
**Last updated:** [July 25, 2022, 10:41am UTC](https://discourse.julialang.org/t/fast-way-of-selecting-rows-in-dataframes-csv-file-with-primary-keys/84535 "2022-07-25T10:41:04Z")

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Hello together, I’m trying to migrate old code from another language to Julia and doing my first steps in Julia by that. I have a csv-File (approx 100 columns, 6000 rows) that comes from a database with primary keys. Wh…

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## [Does MultiJuMP.jl have multithreading or multi-core support?](https://discourse.julialang.org/t/does-multijump-jl-have-multithreading-or-multi-core-support/84739)

<div class="topic-metadata">

**Author:** [@chenr86](https://discourse.julialang.org/u/chenr86)\
**Replies:** 1\
**Last updated:** [July 25, 2022, 8:40am UTC](https://discourse.julialang.org/t/does-multijump-jl-have-multithreading-or-multi-core-support/84739 "2022-07-25T08:40:43Z")

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Hello, I’m using MultiJuMP.jl and Juniper to solve an MINLP problem. It takes more than 2 hours to optimize the problem using one core. I wonder how can I accelerate the calculation process. Can I run my code with multi…

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## [FORTRAN history](https://discourse.julialang.org/t/fortran-history/84735)

<div class="topic-metadata">

**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 1\
**Last updated:** [July 25, 2022, 7:55am UTC](https://discourse.julialang.org/t/fortran-history/84735 "2022-07-25T07:55:40Z")

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This is well worth a read, regarding FORTRAN https://twitter.com/PulpLibrarian/status/1551296747699376131?t=jkcrt0gxiq31UxOX1hs0SA&s=09

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## [Bitwise or](https://discourse.julialang.org/t/bitwise-or/84732)

<div class="topic-metadata">

**Author:** [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Replies:** 3\
**Last updated:** [July 25, 2022, 7:44am UTC](https://discourse.julialang.org/t/bitwise-or/84732 "2022-07-25T07:44:45Z")

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I would like to figure out, if the value of a variable is either one or two. The strange thing is that the result of x == 1 is of type Bool, but bitwise or, "|" makes a difference between (x == 1) and x == 1, is this an…

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## [Plots issues using wayland on arch](https://discourse.julialang.org/t/plots-issues-using-wayland-on-arch/84556)

<div class="topic-metadata">

**Author:** [@charperflow](https://discourse.julialang.org/u/charperflow)\
**Replies:** 19\
**Last updated:** [July 25, 2022, 6:10am UTC](https://discourse.julialang.org/t/plots-issues-using-wayland-on-arch/84556 "2022-07-25T06:10:34Z")

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Hi everyone, I am running an arch-linux machine using wayland for my display manager, and sway for my windows manager. I DO have the QT5 support package installed as well (qt5-wayland). That being said whenever I run a s…

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## [JuliaCon 2022 Local Meetups](https://discourse.julialang.org/t/juliacon-2022-local-meetups/82694)

<div class="topic-metadata">

**Author:** [@rayegun](https://discourse.julialang.org/u/rayegun)\
**Replies:** 9\
**Last updated:** [July 25, 2022, 5:28am UTC](https://discourse.julialang.org/t/juliacon-2022-local-meetups/82694 "2022-07-25T05:28:34Z")

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Hi folks! During JuliaCon 2022 many of the user groups around the world will be hosting in-person meetups! Although JuliaCon will be an online conference again we’re hoping this provides the community with the opportuni…

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## [LU Decomposition: MethodError: no method matching round(::Float64, ::Int64)](https://discourse.julialang.org/t/lu-decomposition-methoderror-no-method-matching-round-float64-int64/84710)

<div class="topic-metadata">

**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 2\
**Last updated:** [July 25, 2022, 5:26am UTC](https://discourse.julialang.org/t/lu-decomposition-methoderror-no-method-matching-round-float64-int64/84710 "2022-07-25T05:26:53Z")

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Hi all, I have read texts on Gauss-Elimination and LU Decomposition. https://web.mit.edu/18.06/www/Spring17/Gaussian-elimination.pdf The problem is when I try the function visualize\_gauss it can’t work: visualize\_gau…

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## [JuliaCon 2022 Meetup in Duesseldorf/Cologne](https://discourse.julialang.org/t/juliacon-2022-meetup-in-duesseldorf-cologne/84038)

<div class="topic-metadata">

**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 4\
**Last updated:** [July 25, 2022, 5:23am UTC](https://discourse.julialang.org/t/juliacon-2022-meetup-in-duesseldorf-cologne/84038 "2022-07-25T05:23:31Z")

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Hi there, we’re working on organising a local Meetup in Duesseldorf/Cologne, most likely on Wednesday 27. Still very much open to suggestions as to where exactly we want to meet. Anyone interested feel free to comment i…

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