# Latest

**URL:** https://discourse.julialang.org/latest.md?page=417

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

**Page:** 418

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## [Is this the right way of distributing the system of differential equations over multiple nodes on a cluster?](https://discourse.julialang.org/t/is-this-the-right-way-of-distributing-the-system-of-differential-equations-over-multiple-nodes-on-a-cluster/113612)

<div class="topic-metadata">

**Author:** [@Shashank](https://discourse.julialang.org/u/Shashank)\
**Replies:** 2\
**Last updated:** [May 6, 2024, 11:51am UTC](https://discourse.julialang.org/t/is-this-the-right-way-of-distributing-the-system-of-differential-equations-over-multiple-nodes-on-a-cluster/113612 "2024-05-06T11:51:40Z")

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I have a large system of ordinary differential equations, and the right-hand side of the equation is coupled and time-consuming. I have written code that parallelizes the evaluation of the right-hand side over multiple t…

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## [Could Someone Guide me on Issue with Array Indexing in Julia?](https://discourse.julialang.org/t/could-someone-guide-me-on-issue-with-array-indexing-in-julia/113897)

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**Author:** [@rich20509](https://discourse.julialang.org/u/rich20509)\
**Replies:** 1\
**Last updated:** [May 6, 2024, 11:13am UTC](https://discourse.julialang.org/t/could-someone-guide-me-on-issue-with-array-indexing-in-julia/113897 "2024-05-06T11:13:41Z")

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Hello there, This is my code: Julia code demonstrating the issue x = \[1, 2, 3, 4, 5\] y = x\[1:3\] Now let’s try to modify y y\[1\] = 10 println("x: ", x) println("y: ", y) I am encountering an unexpected behavior wh…

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## [Problems with distributed package](https://discourse.julialang.org/t/problems-with-distributed-package/113893)

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**Author:** [@greivin](https://discourse.julialang.org/u/greivin)\
**Replies:** 0\
**Last updated:** [May 6, 2024, 10:18am UTC](https://discourse.julialang.org/t/problems-with-distributed-package/113893 "2024-05-06T10:18:37Z")

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I have been having troubles using the Distributed package. I have one function that returns a 100 x 4 array. This array is produced by averaging over some dimensions of a SharedArray that is constructed with a distribute…

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## [Using LoggingExtras to filter LogMessages that were generated from a specific function](https://discourse.julialang.org/t/using-loggingextras-to-filter-logmessages-that-were-generated-from-a-specific-function/113883)

<div class="topic-metadata">

**Author:** [@reumle](https://discourse.julialang.org/u/reumle)\
**Replies:** 1\
**Last updated:** [May 6, 2024, 10:00am UTC](https://discourse.julialang.org/t/using-loggingextras-to-filter-logmessages-that-were-generated-from-a-specific-function/113883 "2024-05-06T10:00:37Z")

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Hello , LoggingExtras lets the coder filter messages that satisfy a condition. Is it possible to keep only the messages that were issued from within a given function Is it possible to combine the above condition with a…

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## [ModelingToolkit.jl -- intermediate symbolic variables calculated from solutions output in the state vector](https://discourse.julialang.org/t/modelingtoolkit-jl-intermediate-symbolic-variables-calculated-from-solutions-output-in-the-state-vector/54024)

<div class="topic-metadata">

**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 5\
**Last updated:** [May 6, 2024, 9:53am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-intermediate-symbolic-variables-calculated-from-solutions-output-in-the-state-vector/54024 "2024-05-06T09:53:23Z")

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When getting a solution from ODEProblem which was created with ModelingToolkit.jl. Is there a way of evaluating symbolic variables/equations that are not in the state vector in plots, etc. Is there an easy way to maybe…

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## [Troubleshooting Inverse Problem with PINNs for Wind Turbine Aerodynamics using NeuralPDE.jl](https://discourse.julialang.org/t/troubleshooting-inverse-problem-with-pinns-for-wind-turbine-aerodynamics-using-neuralpde-jl/113232)

<div class="topic-metadata">

**Author:** [@Alvaro98](https://discourse.julialang.org/u/Alvaro98)\
**Replies:** 12\
**Last updated:** [May 6, 2024, 9:46am UTC](https://discourse.julialang.org/t/troubleshooting-inverse-problem-with-pinns-for-wind-turbine-aerodynamics-using-neuralpde-jl/113232 "2024-05-06T09:46:41Z")

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Hello all, I’m trying to estimate 10 parameters (c1 to c10) of an ODE representing the aerodynamic model of a wind turbine, and I’ve decided to do it via Bayesian inference using physics-informed neural networks (PINN) …

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## [Segmentation fault while trying to call a Julia function compiled to .so file from Python](https://discourse.julialang.org/t/segmentation-fault-while-trying-to-call-a-julia-function-compiled-to-so-file-from-python/113141)

<div class="topic-metadata">

**Author:** [@thecodingbugs](https://discourse.julialang.org/u/thecodingbugs)\
**Replies:** 19\
**Last updated:** [May 6, 2024, 9:36am UTC](https://discourse.julialang.org/t/segmentation-fault-while-trying-to-call-a-julia-function-compiled-to-so-file-from-python/113141 "2024-05-06T09:36:27Z")

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Hello, I am using the examples from PackageCompiler.jl, specifically the MyLib one, and have issues with it. I have compiled MyLib using build.jl file given with it and have created .so files. Now I am trying to use the…

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## [Embed metadata in PDF](https://discourse.julialang.org/t/embed-metadata-in-pdf/62593)

<div class="topic-metadata">

**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 3\
**Last updated:** [May 6, 2024, 8:01am UTC](https://discourse.julialang.org/t/embed-metadata-in-pdf/62593 "2024-05-06T08:01:49Z")

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I am saving a plot as a PDF and I want to embed some metadata about the plot into the pdf file. Is that possible?

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## [SCS not properly installed](https://discourse.julialang.org/t/scs-not-properly-installed/113881)

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**Author:** [@devanshu](https://discourse.julialang.org/u/devanshu)\
**Replies:** 8\
**Last updated:** [May 6, 2024, 6:36am UTC](https://discourse.julialang.org/t/scs-not-properly-installed/113881 "2024-05-06T06:36:56Z")

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I am trying to add QuantumInformation.jl package in julia. But I am getting the following error: ERROR: The following 1 direct dependency failed to precompile: SCS \[c946c3f1-0d1f-5ce8-9dea-7daa1f7e2d13\] Failed to prec…

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## [Static matrix with size 400](https://discourse.julialang.org/t/static-matrix-with-size-400/113843)

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**Author:** [@jiyashxi](https://discourse.julialang.org/u/jiyashxi)\
**Replies:** 7\
**Last updated:** [May 6, 2024, 6:07am UTC](https://discourse.julialang.org/t/static-matrix-with-size-400/113843 "2024-05-06T06:07:33Z")

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Hi, I want to write a function to generate random matrices with size 20x20. I need to use this function frequently but I don’t need to change the matrices generated by it. So the StaticArrays seem to be a good choice. B…

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## [Avoid array duplication](https://discourse.julialang.org/t/avoid-array-duplication/113879)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 5\
**Last updated:** [May 6, 2024, 4:17am UTC](https://discourse.julialang.org/t/avoid-array-duplication/113879 "2024-05-06T04:17:36Z")

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I have a data structure in Julia (CSR matrix, essentially). The same data structure is used in a C++ library that I use from Julia. The question is “how do I avoid the penalty for copying data”? Pass a Julia array to …

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## [Liouvillian superoperator way cannot run by \`timeevolution.master\_dynamic\` of QuantumOptics.jl](https://discourse.julialang.org/t/liouvillian-superoperator-way-cannot-run-by-timeevolution-master-dynamic-of-quantumoptics-jl/113650)

<div class="topic-metadata">

**Author:** [@fqguo](https://discourse.julialang.org/u/fqguo)\
**Replies:** 12\
**Last updated:** [May 6, 2024, 3:02am UTC](https://discourse.julialang.org/t/liouvillian-superoperator-way-cannot-run-by-timeevolution-master-dynamic-of-quantumoptics-jl/113650 "2024-05-06T03:02:22Z")

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When i use the package QuantumOptics.jl to simulate the evolution of Liouvillian superoperator, i find it cannot run by the command timeevolution.master\_dynamic. Because after obtaining the superoperator, i ready to solv…

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## [How to not overdraw gridlines in GeoAxis?](https://discourse.julialang.org/t/how-to-not-overdraw-gridlines-in-geoaxis/113789)

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**Author:** [@yum-yab](https://discourse.julialang.org/u/yum-yab)\
**Replies:** 1\
**Last updated:** [May 6, 2024, 1:06am UTC](https://discourse.julialang.org/t/how-to-not-overdraw-gridlines-in-geoaxis/113789 "2024-05-06T01:06:28Z")

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I want to draw a surface on GeoAxis and keep the gridlines in the axis. Unfortunately after passing a certain value (100 i think) the surface overdraws the gridlines, which looks quite bad and not very intended. Is there…

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## [Using Julia on CoCalc With a Compute Server - William A. Stein](https://discourse.julialang.org/t/using-julia-on-cocalc-with-a-compute-server-william-a-stein/113874)

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**Author:** [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Replies:** 0\
**Last updated:** [May 5, 2024, 8:44pm UTC](https://discourse.julialang.org/t/using-julia-on-cocalc-with-a-compute-server-william-a-stein/113874 "2024-05-05T20:44:08Z")

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William A. Stein demonstrates Julia on a CoCalc Compute Server: If you’re interested in this, please like the video. They’re thinking about sponsoring JuliaCon.

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## [The Einstein Riddle](https://discourse.julialang.org/t/the-einstein-riddle/113750)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 11\
**Last updated:** [May 5, 2024, 8:14pm UTC](https://discourse.julialang.org/t/the-einstein-riddle/113750 "2024-05-05T20:14:56Z")

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From the web: \<\<It’s famously known as the Einstein Riddle because it was supposedly created by Einstein as a young man for fun. But there are some claims online that it actually was invented by the author of Alice’s A…

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## [Equivalent of \`nbconvert\` when using IJulia](https://discourse.julialang.org/t/equivalent-of-nbconvert-when-using-ijulia/113873)

<div class="topic-metadata">

**Author:** [@keynescoefen](https://discourse.julialang.org/u/keynescoefen)\
**Replies:** 3\
**Last updated:** [May 5, 2024, 7:37pm UTC](https://discourse.julialang.org/t/equivalent-of-nbconvert-when-using-ijulia/113873 "2024-05-05T19:37:42Z")

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Hello! I was trying to run the command nbconvert --to pdf --TemplateExporter.exclude\_input=True my\_notebook.ipynb to avoid printing the code output of a cell as per the discussion here. Is there an equivalent in IJu…

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## [Lookup table interpolation of an array](https://discourse.julialang.org/t/lookup-table-interpolation-of-an-array/113787)

<div class="topic-metadata">

**Author:** [@ahrensma](https://discourse.julialang.org/u/ahrensma)\
**Replies:** 7\
**Last updated:** [May 5, 2024, 6:50pm UTC](https://discourse.julialang.org/t/lookup-table-interpolation-of-an-array/113787 "2024-05-05T18:50:10Z")

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Hello, I am not yet fully familiar with Julia and am currently trying to rewrite a Matlab code. I am stumbling with the (Matlab) function interp1. Summarized the code looks like this: A → Type: double(2048x1) B → Type…

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## [Can I use a closure, and if yes how?](https://discourse.julialang.org/t/can-i-use-a-closure-and-if-yes-how/113857)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [May 5, 2024, 6:15pm UTC](https://discourse.julialang.org/t/can-i-use-a-closure-and-if-yes-how/113857 "2024-05-05T18:15:05Z")

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I have the following code: using ControlPlots using KiteModels, KitePodModels, KiteUtils set = deepcopy(se()) kcu::KCU = KCU(set) kps4::KPS4 = KPS4(kcu) include("../examples/plot2d.jl") reltime = 0.0 integrator = Kit…

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## [Opening symbol from a C++ dynamic library](https://discourse.julialang.org/t/opening-symbol-from-a-c-dynamic-library/113866)

<div class="topic-metadata">

**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 3\
**Last updated:** [May 5, 2024, 3:56pm UTC](https://discourse.julialang.org/t/opening-symbol-from-a-c-dynamic-library/113866 "2024-05-05T15:56:44Z")

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I do not have much experience with building C++ libraries. This may be a silly question. The library is built as follows: shell\> g++ -O3 -march=native -fPIC -shared -fopenmp ECL-GC\_12-lib.cpp -o ecl-gc.so I can see th…

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## [Directing Jupyter from IJulia to Homebrew installation of Julia](https://discourse.julialang.org/t/directing-jupyter-from-ijulia-to-homebrew-installation-of-julia/113872)

<div class="topic-metadata">

**Author:** [@keynescoefen](https://discourse.julialang.org/u/keynescoefen)\
**Replies:** 2\
**Last updated:** [May 5, 2024, 5:01pm UTC](https://discourse.julialang.org/t/directing-jupyter-from-ijulia-to-homebrew-installation-of-julia/113872 "2024-05-05T17:01:40Z")

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Hello! I am trying to run a Jupyter notebook like so: using IJulia; notebook(detached=true) and find that my kernel for Julia 10 is not being recognized or located. On my system running which Julia gives me /usr/loc…

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## [There was a problem with ForwardDiff-based Optimization when re-executing the code](https://discourse.julialang.org/t/there-was-a-problem-with-forwarddiff-based-optimization-when-re-executing-the-code/113682)

<div class="topic-metadata">

**Author:** [@chooron](https://discourse.julialang.org/u/chooron)\
**Replies:** 13\
**Last updated:** [May 5, 2024, 3:10pm UTC](https://discourse.julialang.org/t/there-was-a-problem-with-forwarddiff-based-optimization-when-re-executing-the-code/113682 "2024-05-05T15:10:49Z")

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I’m using Optimization.jl to optimize some parameters of ODEProblem, where AutoForwardDiff is used for adtype, when the code is executed for the first time, the program does not show any errors, but when I execute the pr…

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## [Is it possible to make a video with transparency?](https://discourse.julialang.org/t/is-it-possible-to-make-a-video-with-transparency/113860)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 4\
**Last updated:** [May 5, 2024, 2:39pm UTC](https://discourse.julialang.org/t/is-it-possible-to-make-a-video-with-transparency/113860 "2024-05-05T14:39:45Z")

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Is it possible to make a video with transparency? I am remaking the DynamicalSystems.jl logo and I would be happy to make a video itself transparent so that it can obtain whatever background color the website has. The q…

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## [Why is \`getindex\` slower the second time in a vector of vectors?](https://discourse.julialang.org/t/why-is-getindex-slower-the-second-time-in-a-vector-of-vectors/113819)

<div class="topic-metadata">

**Author:** [@alex180500](https://discourse.julialang.org/u/alex180500)\
**Replies:** 7\
**Last updated:** [May 5, 2024, 1:56pm UTC](https://discourse.julialang.org/t/why-is-getindex-slower-the-second-time-in-a-vector-of-vectors/113819 "2024-05-05T13:56:15Z")

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Why is in this function calling the getindex method the second time slower? This function (the smallest working example I could make) is a snippet of a bigger project I’m making on agent based models where I choose a ra…

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## [Elimination of (unnecessary) runtime dispatch allocations](https://discourse.julialang.org/t/elimination-of-unnecessary-runtime-dispatch-allocations/113475)

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**Author:** [@nielsls](https://discourse.julialang.org/u/nielsls)\
**Replies:** 13\
**Last updated:** [May 5, 2024, 12:00pm UTC](https://discourse.julialang.org/t/elimination-of-unnecessary-runtime-dispatch-allocations/113475 "2024-05-05T12:00:26Z")

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Avoiding runtime dispatch is perhaps the #1 optimization advice in Julia forums. As I understand it, the reason is that when the Julia compiler does a runtime dispatch it does not at compile-time neccesarily know the re…

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## [Some notes on using IJulia (and nbextensions) as a Python noob](https://discourse.julialang.org/t/some-notes-on-using-ijulia-and-nbextensions-as-a-python-noob/42902)

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**Author:** [@anon67531922](https://discourse.julialang.org/u/anon67531922)\
**Replies:** 0\
**Last updated:** [July 11, 2020, 5:27pm UTC](https://discourse.julialang.org/t/some-notes-on-using-ijulia-and-nbextensions-as-a-python-noob/42902 "2020-07-11T17:27:55Z")

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Back in 2013, I was looking for an open-source alternative to Matlab (my weapon of choice for the 20+ years prior). The obvious candidates were: Python R Octave I quickly ruled out Octave and didn’t see myself using R…

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## [Filter in function docstrings?](https://discourse.julialang.org/t/filter-in-function-docstrings/113795)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 2\
**Last updated:** [May 5, 2024, 8:51am UTC](https://discourse.julialang.org/t/filter-in-function-docstrings/113795 "2024-05-05T08:51:57Z")

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I’m confused about filtering in docstrings. I know that I can use them in the markdown files of Documenter. But can they be used in regular function docstrings (those embedded in the code)? One thing that is confusing m…

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## [Graph Database in Julia](https://discourse.julialang.org/t/graph-database-in-julia/60159)

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**Author:** [@SergeantMike67](https://discourse.julialang.org/u/SergeantMike67)\
**Replies:** 16\
**Last updated:** [May 5, 2024, 7:17am UTC](https://discourse.julialang.org/t/graph-database-in-julia/60159 "2024-05-05T07:17:42Z")

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Does anyone know if there is a project being developed for a graph database similar to Neo4j? Neo4j is written in Java, and I was thinking that Julia has the characteristics that are most desirable for creating a graph …

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## [How to detect whether the build (compiler options) is a production build](https://discourse.julialang.org/t/how-to-detect-whether-the-build-compiler-options-is-a-production-build/113827)

<div class="topic-metadata">

**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 3\
**Last updated:** [May 5, 2024, 6:35am UTC](https://discourse.julialang.org/t/how-to-detect-whether-the-build-compiler-options-is-a-production-build/113827 "2024-05-05T06:35:36Z")

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Enabling code coverage changes how Julia code is compiled and executed. In particular, code coverage may cause allocations in code that would otherwise be constant-folded: On the other hand, it’s sometimes good to hav…

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## [How to execute additional code before runtests.jl?](https://discourse.julialang.org/t/how-to-execute-additional-code-before-runtests-jl/113854)

<div class="topic-metadata">

**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 2\
**Last updated:** [May 5, 2024, 6:11am UTC](https://discourse.julialang.org/t/how-to-execute-additional-code-before-runtests-jl/113854 "2024-05-05T06:11:42Z")

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I’m trying to solve How to detect whether the build (compiler options) is a production build. I think the right solution is to introduce a global boolean constant whose value would be determined by the user (most often C…

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## [Cannot install PyCall](https://discourse.julialang.org/t/cannot-install-pycall/109256)

<div class="topic-metadata">

**Author:** [@jiang\_ming\_zhang](https://discourse.julialang.org/u/jiang_ming_zhang)\
**Replies:** 7\
**Last updated:** [May 5, 2024, 1:23am UTC](https://discourse.julialang.org/t/cannot-install-pycall/109256 "2024-05-05T01:23:47Z")

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It is the first time I cannot install a package by the standard pkg way. I am using vscode and windows 10. I need this package because it is invoked in another package which I want to use. What is the problem? (@v1.10…

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