# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1344

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

**Page:** 1345

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## [\[ANN\] BenchmarkHistograms.jl](https://discourse.julialang.org/t/ann-benchmarkhistograms-jl/61653)

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**Author:** [@ericphanson](https://discourse.julialang.org/u/ericphanson)\
**Replies:** 7\
**Last updated:** [June 28, 2021, 12:57pm UTC](https://discourse.julialang.org/t/ann-benchmarkhistograms-jl/61653 "2021-06-28T12:57:11Z")

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BenchmarkHistograms.jl is a simple package to provide a UnicodePlots.jl-powered show method for BenchmarkTools’ @benchmark. This idea was originally discussed in BenchmarkTools.jl#180. BenchmarkHistograms works by expor…

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## [Using Arrow.DictEncode()](https://discourse.julialang.org/t/using-arrow-dictencode/63788)

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**Author:** [@jbshannon](https://discourse.julialang.org/u/jbshannon)\
**Replies:** 1\
**Last updated:** [June 30, 2021, 10:45pm UTC](https://discourse.julialang.org/t/using-arrow-dictencode/63788 "2021-06-30T22:45:47Z")

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How exactly does the Arrow.DictEncode() method work? I’ve tried using it to signal that a DataFrame column be dictionary encoding when writing to a .arrow file, but I can’t see any indication that this works. I’ve looked…

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## [Unsatisfiable requirements detected for package DifferentialEquations \[0c46a032\]](https://discourse.julialang.org/t/unsatisfiable-requirements-detected-for-package-differentialequations-0c46a032/63860)

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**Author:** [@minhnguyen](https://discourse.julialang.org/u/minhnguyen)\
**Replies:** 7\
**Last updated:** [June 30, 2021, 10:43pm UTC](https://discourse.julialang.org/t/unsatisfiable-requirements-detected-for-package-differentialequations-0c46a032/63860 "2021-06-30T22:43:23Z")

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Hi guys, I have problems running the Differential Equation package although I have used the lines “import Pkg” or “using Pkg” and "Pkg.add(“DIfferentialEquations”). My julia’s current version is 1.6.1. Please help me re…

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## [Substring replacement](https://discourse.julialang.org/t/substring-replacement/63794)

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**Author:** [@dpkwhan](https://discourse.julialang.org/u/dpkwhan)\
**Replies:** 6\
**Last updated:** [June 30, 2021, 10:35pm UTC](https://discourse.julialang.org/t/substring-replacement/63794 "2021-06-30T22:35:31Z")

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Why does the following not work? replace("2021-06-29T23:14:20", "-" =\> "", ":" =\> "")

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## [\[ANN\] PostgresORM.jl: Object Relational Mapping for PostgreSQL](https://discourse.julialang.org/t/ann-postgresorm-jl-object-relational-mapping-for-postgresql/63847)

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**Author:** [@tencnivel](https://discourse.julialang.org/u/tencnivel)\
**Replies:** 0\
**Last updated:** [June 30, 2021, 5:34pm UTC](https://discourse.julialang.org/t/ann-postgresorm-jl-object-relational-mapping-for-postgresql/63847 "2021-06-30T17:34:32Z")

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I’m happy to announce PostgresORM.jl, a Julia ORM for PostgreSQL. This package was developed to help us create Julia based web applications. Before this public release, it has been used in production for over a year in…

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## [Julia 1.6.1 upgrade and interference with RStudio Git?](https://discourse.julialang.org/t/julia-1-6-1-upgrade-and-interference-with-rstudio-git/63855)

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**Author:** [@fkrauer](https://discourse.julialang.org/u/fkrauer)\
**Replies:** 2\
**Last updated:** [June 30, 2021, 8:25pm UTC](https://discourse.julialang.org/t/julia-1-6-1-upgrade-and-interference-with-rstudio-git/63855 "2021-06-30T20:25:51Z")

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Hi everyone I just upgraded Julia from 1.5.2 to 1.6.1, and something odd happened. Immediately afterwards, my Git tab disappeared from RStudio, and I cannot use Git version control anymore in RStudio. git init returns f…

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## [Benchmark parts of a function?](https://discourse.julialang.org/t/benchmark-parts-of-a-function/63844)

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**Author:** [@eduardovrs](https://discourse.julialang.org/u/eduardovrs)\
**Replies:** 3\
**Last updated:** [June 30, 2021, 7:37pm UTC](https://discourse.julialang.org/t/benchmark-parts-of-a-function/63844 "2021-06-30T19:37:21Z")

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Hello everyone, I am trying to benchmark the operations inside a function to have an idea where would be best to focus to try to optimize, and at the moment I do something similar to: function foo() a = @btime rand…

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## [Parse, don't validate](https://discourse.julialang.org/t/parse-dont-validate/63618)

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**Author:** [@rikh](https://discourse.julialang.org/u/rikh)\
**Replies:** 10\
**Last updated:** [June 30, 2021, 7:36pm UTC](https://discourse.julialang.org/t/parse-dont-validate/63618 "2021-06-30T19:36:28Z")

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The Parse, don’t validate blog post came by on Hacker News again. As far as I understand, this is advertising to use type checking instead of checking the object each time. Are there valuable lessons to be learned in thi…

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## [How to estimate Jaccard similarity/distances with MinHash.jl](https://discourse.julialang.org/t/how-to-estimate-jaccard-similarity-distances-with-minhash-jl/63843)

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**Author:** [@rohan.m](https://discourse.julialang.org/u/rohan.m)\
**Replies:** 3\
**Last updated:** [June 30, 2021, 7:24pm UTC](https://discourse.julialang.org/t/how-to-estimate-jaccard-similarity-distances-with-minhash-jl/63843 "2021-06-30T19:24:55Z")

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Hello, I want to rapidly estimate a distance matrix using Jaccard distance (1 - Jaccard similarity) for a large binary matrix (rows are genomes, columns are genes found in common across genomes). MinHash seems like the …

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## [How to run (activate?) a Jupyter Notebook in a specific environment](https://discourse.julialang.org/t/how-to-run-activate-a-jupyter-notebook-in-a-specific-environment/63841)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 12\
**Last updated:** [June 30, 2021, 5:38pm UTC](https://discourse.julialang.org/t/how-to-run-activate-a-jupyter-notebook-in-a-specific-environment/63841 "2021-06-30T17:38:35Z")

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I am trying to run a Jupyter notebook (and a project in general) in a specific environment with only a limited number of packages. I have created a folder. In my terminal, I navigated to this folder, started julia, and …

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## [One line updating of rows of a matrix](https://discourse.julialang.org/t/one-line-updating-of-rows-of-a-matrix/63845)

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**Author:** [@Mark\_Williams](https://discourse.julialang.org/u/Mark_Williams)\
**Replies:** 6\
**Last updated:** [June 30, 2021, 5:29pm UTC](https://discourse.julialang.org/t/one-line-updating-of-rows-of-a-matrix/63845 "2021-06-30T17:29:05Z")

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I have a simple recursive procedure to populate a matrix which can be made easier by populating row by row. i.e. calculating the row and copying it to the matrix. I can’t find a way of making it work and returning the ma…

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## [Julia Programming Book Recommendations](https://discourse.julialang.org/t/julia-programming-book-recommendations/63739)

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**Author:** [@wildman](https://discourse.julialang.org/u/wildman)\
**Replies:** 7\
**Last updated:** [June 30, 2021, 4:29pm UTC](https://discourse.julialang.org/t/julia-programming-book-recommendations/63739 "2021-06-30T16:29:02Z")

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Hello, I’m very new to the Julia programming language but I do have considerable experience using R and Python. Are there any book recommendations for using Julia, please? Much appreciated.

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## [Unable to add package Oceananigans.jl](https://discourse.julialang.org/t/unable-to-add-package-oceananigans-jl/63827)

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**Author:** [@SUMAN\_SHEKHAR](https://discourse.julialang.org/u/SUMAN_SHEKHAR)\
**Replies:** 4\
**Last updated:** [June 30, 2021, 4:19pm UTC](https://discourse.julialang.org/t/unable-to-add-package-oceananigans-jl/63827 "2021-06-30T16:19:01Z")

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I have Julia v1.6.1 and I have tried to add Oceananigans package inside it but I am getting git errors that I am unable to crack. Here is the full error message- julia\> using Pkg julia\> Pkg.add("Oceananigans"); Pkg.sta…

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## [Can Fortran subroutines be passed as argument to the function called in ccall](https://discourse.julialang.org/t/can-fortran-subroutines-be-passed-as-argument-to-the-function-called-in-ccall/56426)

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**Author:** [@amarcotte59](https://discourse.julialang.org/u/amarcotte59)\
**Replies:** 5\
**Last updated:** [June 30, 2021, 3:45pm UTC](https://discourse.julialang.org/t/can-fortran-subroutines-be-passed-as-argument-to-the-function-called-in-ccall/56426 "2021-06-30T15:45:10Z")

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I searched and saw documentation and discussions on passing different types of variables but nothing on passing subroutines or functions as argument in ccall. We are in the process of converting our fortran programs. Mos…

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## [\[Convex.jl\] Objective function of matrix factorization with missing data](https://discourse.julialang.org/t/convex-jl-objective-function-of-matrix-factorization-with-missing-data/34253)

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**Author:** [@4aHxKzD](https://discourse.julialang.org/u/4aHxKzD)\
**Replies:** 21\
**Last updated:** [June 30, 2021, 3:05pm UTC](https://discourse.julialang.org/t/convex-jl-objective-function-of-matrix-factorization-with-missing-data/34253 "2021-06-30T15:05:27Z")

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I’m trying to solve a matrix factorization problem with alternating minimization. My data matrix has missing entries and because of that I can not simply write my objective function as: # A is a n x m data matrix n, m…

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## [Module/file/line for log message generated by a macro](https://discourse.julialang.org/t/module-file-line-for-log-message-generated-by-a-macro/63835)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [June 30, 2021, 1:40pm UTC](https://discourse.julialang.org/t/module-file-line-for-log-message-generated-by-a-macro/63835 "2021-06-30T13:40:11Z")

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I have a module which exports a macro that checks something, implemented in a function, and warns if an invariant is not maintained, via @warn. I want to provide correct location information, but can’t figure it out: eg…

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## [Julia + Notebook memory leak](https://discourse.julialang.org/t/julia-notebook-memory-leak/63830)

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**Author:** [@Xeos](https://discourse.julialang.org/u/Xeos)\
**Replies:** 2\
**Last updated:** [June 30, 2021, 2:41pm UTC](https://discourse.julialang.org/t/julia-notebook-memory-leak/63830 "2021-06-30T14:41:20Z")

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Hi, I’ve started trying out jupyterlab with IJulia to see if I could free myself from some large data loading processes that take a lot of time at every run. The CSV I’m working on is decently large (2GB) which then ta…

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## [Why do bigfloats allocate that much ? Could a native rewrite solve the problem?](https://discourse.julialang.org/t/why-do-bigfloats-allocate-that-much-could-a-native-rewrite-solve-the-problem/63809)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 4\
**Last updated:** [June 30, 2021, 1:40pm UTC](https://discourse.julialang.org/t/why-do-bigfloats-allocate-that-much-could-a-native-rewrite-solve-the-problem/63809 "2021-06-30T13:40:29Z")

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Hi. Everything is in the title: I dont think I understood why BigFloats allocate that much, and why nothing could be done about it. Is there some source, article or doc that explains this ? As @JeffreySarnoff showed in…

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## [Converting BitVector arbitrary length components into UInt64, Float64, etc](https://discourse.julialang.org/t/converting-bitvector-arbitrary-length-components-into-uint64-float64-etc/63829)

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**Author:** [@costrouc](https://discourse.julialang.org/u/costrouc)\
**Replies:** 1\
**Last updated:** [June 30, 2021, 1:38pm UTC](https://discourse.julialang.org/t/converting-bitvector-arbitrary-length-components-into-uint64-float64-etc/63829 "2021-06-30T13:38:34Z")

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Hey all! New to Julia and was looking apply a use case I have to better understand the language. I have binary packet data similar to a network packet ethernet/ip/tcp where I need to be able to convert packets and their …

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## [Multithreading in LoopVectorization.jl](https://discourse.julialang.org/t/multithreading-in-loopvectorization-jl/63815)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 8\
**Last updated:** [June 30, 2021, 1:19pm UTC](https://discourse.julialang.org/t/multithreading-in-loopvectorization-jl/63815 "2021-06-30T13:19:41Z")

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I would like to give LoopVectorization.jl a try. As far as I understand, to speed up a computation which involves Threads.@threads for loop, I need to replace the macro Threads.@threads with @tturbo. Now, I would like t…

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## [Why is Matrix multiplication with an UpperTriangular slower than with normal Matrix?](https://discourse.julialang.org/t/why-is-matrix-multiplication-with-an-uppertriangular-slower-than-with-normal-matrix/63824)

<div class="topic-metadata">

**Author:** [@zsoerenm](https://discourse.julialang.org/u/zsoerenm)\
**Replies:** 2\
**Last updated:** [June 30, 2021, 1:14pm UTC](https://discourse.julialang.org/t/why-is-matrix-multiplication-with-an-uppertriangular-slower-than-with-normal-matrix/63824 "2021-06-30T13:14:55Z")

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Why is Matrix multiplication with an UpperTriangular slower than with normal Matrix? I would expect it to be faster: using LinearAlgebra, BenchmarkTools A = randn(60,60); B = randn(60,60); @btime $A \* $B' # 19.693 μs (…

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## [Slow \`convert\` for arrays. Use multiple dispatch instead?](https://discourse.julialang.org/t/slow-convert-for-arrays-use-multiple-dispatch-instead/63822)

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**Author:** [@manuelbb-upb](https://discourse.julialang.org/u/manuelbb-upb)\
**Replies:** 3\
**Last updated:** [June 30, 2021, 1:09pm UTC](https://discourse.julialang.org/t/slow-convert-for-arrays-use-multiple-dispatch-instead/63822 "2021-06-30T13:09:27Z")

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I was wondering why something like x = rand(10) convert(Vector{Float64}, x) is relatively slow, when x does not even need to be converted. I noticed that in Julia base the convert method is defined as convert(::Type{…

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## [Read NULL as missing in dataframe](https://discourse.julialang.org/t/read-null-as-missing-in-dataframe/63823)

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**Author:** [@Ismam](https://discourse.julialang.org/u/Ismam)\
**Replies:** 1\
**Last updated:** [June 30, 2021, 12:14pm UTC](https://discourse.julialang.org/t/read-null-as-missing-in-dataframe/63823 "2021-06-30T12:14:28Z")

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Hi, I’m reading a csv file (originally obtained from SQL) that has the string “NULL” to signify no value. This is not an empty string (although I am curious how that gets tackled too). How do I read this string as a mi…

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## [ModelingToolkit: troubles using ode\_order\_lowering (A differentiated state's operation must be a \`Sym\`)](https://discourse.julialang.org/t/modelingtoolkit-troubles-using-ode-order-lowering-a-differentiated-states-operation-must-be-a-sym/63716)

<div class="topic-metadata">

**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 1\
**Last updated:** [June 30, 2021, 11:56am UTC](https://discourse.julialang.org/t/modelingtoolkit-troubles-using-ode-order-lowering-a-differentiated-states-operation-must-be-a-sym/63716 "2021-06-30T11:56:25Z")

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I am trying to model a simple mechanical chain composed of a few masses interconnected with springs and exposed to friction. Such model comes in the form of a few coupled second-order differential equations. These I mode…

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## [MKL building error on JuliaPro 1.5.4](https://discourse.julialang.org/t/mkl-building-error-on-juliapro-1-5-4/63758)

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**Author:** [@AndreyO](https://discourse.julialang.org/u/AndreyO)\
**Replies:** 6\
**Last updated:** [June 30, 2021, 11:39am UTC](https://discourse.julialang.org/t/mkl-building-error-on-juliapro-1-5-4/63758 "2021-06-30T11:39:51Z")

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Hello, guys! I’m using JuliaPro 1.5.4 and can’t get MKL.jl to build. The following error pops up: julia\> Pkg.build("MKL"; verbose=true) Building MKL → \`\<USER\_PATH\>\\.julia\\packages\\MKL\\R4HOk\\deps\\build.log\` \[ Info: S…

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## [Unable to use Plots](https://discourse.julialang.org/t/unable-to-use-plots/63812)

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**Author:** [@development\_mentor](https://discourse.julialang.org/u/development_mentor)\
**Replies:** 4\
**Last updated:** [June 30, 2021, 11:28am UTC](https://discourse.julialang.org/t/unable-to-use-plots/63812 "2021-06-30T11:28:42Z")

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I tried downloading Plots package. But during installation, it stopped so I exited. Then when I wanted to repeat the installation it succeeded. But when I want to use Plots it gives me errors like that: The following pa…

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## [\[ANN\] Fezzik.jl: build locally for better integration with VSCode](https://discourse.julialang.org/t/ann-fezzik-jl-build-locally-for-better-integration-with-vscode/63810)

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**Author:** [@TsurHerman](https://discourse.julialang.org/u/TsurHerman)\
**Replies:** 0\
**Last updated:** [June 30, 2021, 9:28am UTC](https://discourse.julialang.org/t/ann-fezzik-jl-build-locally-for-better-integration-with-vscode/63810 "2021-06-30T09:28:56Z")

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Fezzik.jl simplifies the process of building custom sys images, Without a custom sysimg , working with Julia and going through the same jitting over and over again is a pain. However up until now the default brute\_buil…

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## [How to not precompile an optional dependency?](https://discourse.julialang.org/t/how-to-not-precompile-an-optional-dependency/63807)

<div class="topic-metadata">

**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [June 30, 2021, 8:32am UTC](https://discourse.julialang.org/t/how-to-not-precompile-an-optional-dependency/63807 "2021-06-30T08:32:16Z")

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Hi, I’m working on a project that requires a proprietary solver (Gurobi and a license) for a particular feature. I would like other users to be able to use the package even though they do not have installed gurobi on th…

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## [Update parameters in ModelingToolkit using callbacks](https://discourse.julialang.org/t/update-parameters-in-modelingtoolkit-using-callbacks/63770)

<div class="topic-metadata">

**Author:** [@jairorua](https://discourse.julialang.org/u/jairorua)\
**Replies:** 12\
**Last updated:** [June 30, 2021, 8:19am UTC](https://discourse.julialang.org/t/update-parameters-in-modelingtoolkit-using-callbacks/63770 "2021-06-30T08:19:30Z")

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Hello, I was trying to create a simple control loop with modelingtoolkit. The idea was to have a generic controller whose setpoint can be changed using callbacks during a dynamic simulation. For example: using Modelin…

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## [Suggestion: use PEP-like process for changes](https://discourse.julialang.org/t/suggestion-use-pep-like-process-for-changes/63494)

<div class="topic-metadata">

**Author:** [@paulmelis](https://discourse.julialang.org/u/paulmelis)\
**Replies:** 37\
**Last updated:** [June 30, 2021, 8:06am UTC](https://discourse.julialang.org/t/suggestion-use-pep-like-process-for-changes/63494 "2021-06-30T08:06:00Z")

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Meta-point in response this remark by @skoffer (with which I agree): with other languages, say Python and Go, more structured processes to discuss possible language evolution and improvements have been put in place over…

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