# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1542

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

**Page:** 1543

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## ['Introduction to Euclidean vector spaces with Julia' a video tutorial using Pluto](https://discourse.julialang.org/t/introduction-to-euclidean-vector-spaces-with-julia-a-video-tutorial-using-pluto/52086)

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**Author:** [@forestacorn](https://discourse.julialang.org/u/forestacorn)\
**Replies:** 0\
**Last updated:** [December 19, 2020, 12:28pm UTC](https://discourse.julialang.org/t/introduction-to-euclidean-vector-spaces-with-julia-a-video-tutorial-using-pluto/52086 "2020-12-19T12:28:22Z")

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A pleasant back to basics video tutorial entitled Introduction to Euclidean vector spaces with Julia using a Pluto notebook by Juan Klopper. A few sections are also a good reminder on how to write Latex expressions. The…

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## [\[ANN\] ChannelBuffers](https://discourse.julialang.org/t/ann-channelbuffers/51323)

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**Author:** [@klacru](https://discourse.julialang.org/u/klacru)\
**Replies:** 1\
**Last updated:** [December 19, 2020, 10:50am UTC](https://discourse.julialang.org/t/ann-channelbuffers/51323 "2020-12-19T10:50:51Z")

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This parallel Tasks/Threads package ChannelBuffers implements piped streams in Julia. Typical usage: curl("...file.tgz") | gunzip() | tarx("target-dir") |\> run |\> wait Each job is performed in a separate task; tasks …

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## [Impossible to sort Sym elements](https://discourse.julialang.org/t/impossible-to-sort-sym-elements/51810)

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**Author:** [@fms-1988](https://discourse.julialang.org/u/fms-1988)\
**Replies:** 9\
**Last updated:** [December 19, 2020, 10:55am UTC](https://discourse.julialang.org/t/impossible-to-sort-sym-elements/51810 "2020-12-19T10:55:06Z")

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I’m trying to order elements (Sym) from a Tuple. I’ve tried several codes but nothing works. I will be grateful if anyone can help. using SymPy using LinearAlgebra a1 = \[Sym("a\_$i^$j") for i=1 for j=1:2\] a2 = \[Sym("a\_…

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## [Resolve mismatch between running Julia and the compatibility section](https://discourse.julialang.org/t/resolve-mismatch-between-running-julia-and-the-compatibility-section/52064)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [December 19, 2020, 6:16am UTC](https://discourse.julialang.org/t/resolve-mismatch-between-running-julia-and-the-compatibility-section/52064 "2020-12-19T06:16:03Z")

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Consider a project: Let us say I have specified compatibility as Julia 1.5. Now I run 1.6, which violates the compatibility requirement. When this happens with packages, activating the environment fails. However with the…

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## [How was this discourse forum setup?](https://discourse.julialang.org/t/how-was-this-discourse-forum-setup/52076)

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**Author:** [@systems](https://discourse.julialang.org/u/systems)\
**Replies:** 3\
**Last updated:** [December 19, 2020, 4:06am UTC](https://discourse.julialang.org/t/how-was-this-discourse-forum-setup/52076 "2020-12-19T04:06:05Z")

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May I ask please how was this forum setup Does it use one of the available plan Discourse pricing | Discourse - Civilized Discussion Or was it installed from the source and is managed by one of the site admins (I am a…

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## [How to run julia in google colab](https://discourse.julialang.org/t/how-to-run-julia-in-google-colab/43169)

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**Author:** [@waladraidi](https://discourse.julialang.org/u/waladraidi)\
**Replies:** 2\
**Last updated:** [December 19, 2020, 3:30am UTC](https://discourse.julialang.org/t/how-to-run-julia-in-google-colab/43169 "2020-12-19T03:30:19Z")

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Hi everyone could you please help me how to run Julia in google colab at the beginning, and then how to run a file which is .jI in google colab

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## [Weave No Longer Works in v1.5](https://discourse.julialang.org/t/weave-no-longer-works-in-v1-5/49485)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 6\
**Last updated:** [December 19, 2020, 12:09am UTC](https://discourse.julialang.org/t/weave-no-longer-works-in-v1-5/49485 "2020-12-19T00:09:54Z")

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I recently upgraded to v1.5, and tried to weave a document. When I reloaded Weave, and tried using I got this warning, and it won’t start a document. I tried updating my packages, do I need fix something in Weave, is w…

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## [Is there a Python Celery equivalent in Julia?](https://discourse.julialang.org/t/is-there-a-python-celery-equivalent-in-julia/52071)

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**Author:** [@guilhermebodin](https://discourse.julialang.org/u/guilhermebodin)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 11:14pm UTC](https://discourse.julialang.org/t/is-there-a-python-celery-equivalent-in-julia/52071 "2020-12-18T23:14:15Z")

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Hello, I am very new to this task queue and message broker thing but is there a package or a way to have task queues just like on celery Celery - Distributed Task Queue — Celery 5.2.7 documentation?

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## [Parametric constructor, promotion and splatting (...)](https://discourse.julialang.org/t/parametric-constructor-promotion-and-splatting/52066)

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**Author:** [@mocalvao](https://discourse.julialang.org/u/mocalvao)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 10:52pm UTC](https://discourse.julialang.org/t/parametric-constructor-promotion-and-splatting/52066 "2020-12-18T22:52:19Z")

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Hi there, I am reading the page ParametricConstructors of the manual, where a struct Point is defined as: struct Point{T\<:Real} x::T y::T Point{T}(x,y) where {T\<:Real} = new(x,y) …

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## [var::MyType the variable keeps MyType as type and can't change further on](https://discourse.julialang.org/t/var-mytype-the-variable-keeps-mytype-as-type-and-cant-change-further-on/51955)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 8\
**Last updated:** [December 18, 2020, 10:37pm UTC](https://discourse.julialang.org/t/var-mytype-the-variable-keeps-mytype-as-type-and-cant-change-further-on/51955 "2020-12-18T22:37:19Z")

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Hey community, I know that Julia is dynamic and variables can change type. But would it be nice to have a way of restricting that? My ideas is: var::Int64 = 10 var = 10.0 # throws an error var2 = 10 var2 = 10.0 # no…

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## [How to fix manifest issues (mistake when merging compathelper pr)](https://discourse.julialang.org/t/how-to-fix-manifest-issues-mistake-when-merging-compathelper-pr/52070)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 9:45pm UTC](https://discourse.julialang.org/t/how-to-fix-manifest-issues-mistake-when-merging-compathelper-pr/52070 "2020-12-18T21:45:04Z")

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can I delete a manifest.toml and regenerate it somehow? I was resolving merge conflicts from compathelper pr’s and I made some mistakes (coffee not on-line yet)…

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## [Distance matrix + clustering with custom distance function](https://discourse.julialang.org/t/distance-matrix-clustering-with-custom-distance-function/52026)

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**Author:** [@vshesh](https://discourse.julialang.org/u/vshesh)\
**Replies:** 6\
**Last updated:** [December 18, 2020, 8:43pm UTC](https://discourse.julialang.org/t/distance-matrix-clustering-with-custom-distance-function/52026 "2020-12-18T20:43:39Z")

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Hi I’m new to julia and trying to figure out the best way to compute some distance matrices and evaluate how good my clustering is… I have a custom distance function like this: dist(w::Array{\<:Real,1}, p::Int64 = 2) = …

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## [Can you beat our solutions for the raindrops exercise?](https://discourse.julialang.org/t/can-you-beat-our-solutions-for-the-raindrops-exercise/52006)

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**Author:** [@Luapulu](https://discourse.julialang.org/u/Luapulu)\
**Replies:** 16\
**Last updated:** [December 18, 2020, 8:29pm UTC](https://discourse.julialang.org/t/can-you-beat-our-solutions-for-the-raindrops-exercise/52006 "2020-12-18T20:29:48Z")

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So, @cmcaine, @SaschaMann, @tomerarnon and I have been discussing the raindrops exercise in Exercism and solutions to it. The ExerciseCreate a function raindrops, which will return a string given a number as follows: …

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## [Retour in installing sole packages](https://discourse.julialang.org/t/retour-in-installing-sole-packages/52068)

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**Author:** [@koalatif](https://discourse.julialang.org/u/koalatif)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 8:16pm UTC](https://discourse.julialang.org/t/retour-in-installing-sole-packages/52068 "2020-12-18T20:16:07Z")

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Error occures when I want to install some packages like Plots, Plutôt, etc. Here is a Snapshot :

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## [Erratic segmentation fault - from a package using \`ccall\`](https://discourse.julialang.org/t/erratic-segmentation-fault-from-a-package-using-ccall/52049)

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**Author:** [@stla](https://discourse.julialang.org/u/stla)\
**Replies:** 6\
**Last updated:** [December 18, 2020, 7:59pm UTC](https://discourse.julialang.org/t/erratic-segmentation-fault-from-a-package-using-ccall/52049 "2020-12-18T19:59:08Z")

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Hello, I started a new project: Junuran, a Julia wrapper of the UNU.RAN C library. So far the package only allows to sample from a continuous multivariate distribution when the user gives the density of the distributio…

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## [Passing views to function without allocation](https://discourse.julialang.org/t/passing-views-to-function-without-allocation/51992)

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**Author:** [@Jae-Mo\_Lihm](https://discourse.julialang.org/u/Jae-Mo_Lihm)\
**Replies:** 14\
**Last updated:** [December 18, 2020, 7:12pm UTC](https://discourse.julialang.org/t/passing-views-to-function-without-allocation/51992 "2020-12-18T19:12:35Z")

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I want to perform matrix vector multiplication of size (N^2, M) \* (M), and then reshape the output vector of size (N^2) to a (N, N) matrix. To do this without allocation, I tried using 1d view of the matrix. Directly c…

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## [Zygote fails with gradients of destructured/restructured RNNs](https://discourse.julialang.org/t/zygote-fails-with-gradients-of-destructured-restructured-rnns/52065)

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**Author:** [@noumea](https://discourse.julialang.org/u/noumea)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 6:59pm UTC](https://discourse.julialang.org/t/zygote-fails-with-gradients-of-destructured-restructured-rnns/52065 "2020-12-18T18:59:24Z")

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I am trying to optimize a NN with an Optim.jl optimizer by using destructure/restructure on the model, and Zygote to obtain the gradient of the loss function. I noticed that Zygote does not seem to be able to calculate t…

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## [Do I have to implement Flux.testmode! for my own models?](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038)

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**Author:** [@maxfreu](https://discourse.julialang.org/u/maxfreu)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 6:00pm UTC](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038 "2020-12-18T18:00:58Z")

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Hi, I implemented a U-Net and would like to switch between train and test mode for the BN layers. struct Unet encoder # tuple of chains decoder # tuple of UpBlocks segmentation\_head # normal conv layer end …

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## [Amalie Emmy Noether Fellowship in applied mathematics and scientific computing at Brookhaven National Laboratory](https://discourse.julialang.org/t/amalie-emmy-noether-fellowship-in-applied-mathematics-and-scientific-computing-at-brookhaven-national-laboratory/52062)

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**Author:** [@nurban](https://discourse.julialang.org/u/nurban)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 5:22pm UTC](https://discourse.julialang.org/t/amalie-emmy-noether-fellowship-in-applied-mathematics-and-scientific-computing-at-brookhaven-national-laboratory/52062 "2020-12-18T17:22:57Z")

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I would like to advertise the following 2-year postdoctoral fellowship in applied mathematics and scientific computing at Brookhaven National Laboratory, a U.S. Department of Energy research institution on Long Island, N…

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## [Fast reading of multiple big-endian binary files](https://discourse.julialang.org/t/fast-reading-of-multiple-big-endian-binary-files/52060)

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**Author:** [@Thomas\_Lei](https://discourse.julialang.org/u/Thomas_Lei)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 5:13pm UTC](https://discourse.julialang.org/t/fast-reading-of-multiple-big-endian-binary-files/52060 "2020-12-18T17:13:47Z")

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Hi all, I have to read and preprocess a huge quantity of binary (big-endian) data from thousands of files. I managed to get everything to work properly, but my function is slow… However, as I’m a Julia beginner, I doubt…

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## [What makes Julia dynamic (easy) and as fast as C?](https://discourse.julialang.org/t/what-makes-julia-dynamic-easy-and-as-fast-as-c/52047)

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**Author:** [@vedasulo](https://discourse.julialang.org/u/vedasulo)\
**Replies:** 4\
**Last updated:** [December 18, 2020, 5:11pm UTC](https://discourse.julialang.org/t/what-makes-julia-dynamic-easy-and-as-fast-as-c/52047 "2020-12-18T17:11:44Z")

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What makes Julia (Dynamic(easy) and as fast as C? Why C or C++ didnt implemented dynamic (easy language) way? If we have came in end where Dynamic(high level language) can be as fast as C/C++… Would it replace all the…

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## [Julia BeNeLux Meetup group](https://discourse.julialang.org/t/julia-benelux-meetup-group/51926)

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**Author:** [@zgornel](https://discourse.julialang.org/u/zgornel)\
**Replies:** 4\
**Last updated:** [December 18, 2020, 5:03pm UTC](https://discourse.julialang.org/t/julia-benelux-meetup-group/51926 "2020-12-18T17:03:17Z")

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Small announcement: I have recently become the organizer of the Julia Benelux Meetup group. If anyone lives in the area and has any topics and suggestions for future events, they’re welcome to contact me here or drop me …

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## [Model Predictive Controller only works for certain values](https://discourse.julialang.org/t/model-predictive-controller-only-works-for-certain-values/51916)

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**Author:** [@LukasLundgren96](https://discourse.julialang.org/u/LukasLundgren96)\
**Replies:** 8\
**Last updated:** [December 18, 2020, 3:43pm UTC](https://discourse.julialang.org/t/model-predictive-controller-only-works-for-certain-values/51916 "2020-12-18T15:43:23Z")

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I am using JuMP and Ipopt to solve an online optimization for a Furuta pendulum. Quite quickly I got it running in simulation but for the real pendulum I had some trouble. The trouble was solved by substituting one of th…

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## [Warnings upon loading a custom sysimage](https://discourse.julialang.org/t/warnings-upon-loading-a-custom-sysimage/50141)

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**Author:** [@Peter\_Adelman](https://discourse.julialang.org/u/Peter_Adelman)\
**Replies:** 1\
**Last updated:** [December 18, 2020, 3:34pm UTC](https://discourse.julialang.org/t/warnings-upon-loading-a-custom-sysimage/50141 "2020-12-18T15:34:21Z")

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I have a script (simplified a bit here) that I use to make a custom sysimage with over 100 packages, including Weave. It has been amazingly useful for speeding up development / tests and works great. It parses the Manif…

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## [Loading a package from a fork](https://discourse.julialang.org/t/loading-a-package-from-a-fork/52017)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 10\
**Last updated:** [December 18, 2020, 3:03pm UTC](https://discourse.julialang.org/t/loading-a-package-from-a-fork/52017 "2020-12-18T15:03:16Z")

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Apologies but I can’t seem to find clear documentation on this. \[and the little I did find didn’t work\] I have created a fork from a package on github, and before tinkering with it, I want to see how to just load the p…

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## [Julia -e "subtypes(Real)" fails](https://discourse.julialang.org/t/julia-e-subtypes-real-fails/51991)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 6\
**Last updated:** [December 18, 2020, 1:57pm UTC](https://discourse.julialang.org/t/julia-e-subtypes-real-fails/51991 "2020-12-18T13:57:09Z")

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As simple as that. Any file calling subtypes fails to be run as a script, or loaded with julia -i: % julia -e "subtypes(Real)" ERROR: UndefVarError: subtypes not defined Stacktrace: \[1\] top-level scope at none:1 lean…

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## [Simple question: Time to move from 1.0 to 1.5?](https://discourse.julialang.org/t/simple-question-time-to-move-from-1-0-to-1-5/52009)

<div class="topic-metadata">

**Author:** [@HexSpin](https://discourse.julialang.org/u/HexSpin)\
**Replies:** 9\
**Last updated:** [December 18, 2020, 1:56pm UTC](https://discourse.julialang.org/t/simple-question-time-to-move-from-1-0-to-1-5/52009 "2020-12-18T13:56:53Z")

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I’m new to Julia, but having great success speeding up what I once did in python. ‘Threads’ might offer additional performance - but, as I understand it, it’s not available in release 1.0 and I must upgrade to 1.5. Wi…

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## [Unexpected error when installing any package](https://discourse.julialang.org/t/unexpected-error-when-installing-any-package/52045)

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**Author:** [@Abdou](https://discourse.julialang.org/u/Abdou)\
**Replies:** 0\
**Last updated:** [December 18, 2020, 1:48pm UTC](https://discourse.julialang.org/t/unexpected-error-when-installing-any-package/52045 "2020-12-18T13:48:25Z")

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I recently installed Net Framwork 4.8 on my Windows 7 pack 1. After that when installing any package I get this error : (@v1.5) pkg\> add GitHub #For example Updating registry at myhome\\.julia\\registries\\General ERRO…

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## [Synchronizing 2 loops in multi-threading](https://discourse.julialang.org/t/synchronizing-2-loops-in-multi-threading/52015)

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**Author:** [@dopamine](https://discourse.julialang.org/u/dopamine)\
**Replies:** 2\
**Last updated:** [December 18, 2020, 1:40pm UTC](https://discourse.julialang.org/t/synchronizing-2-loops-in-multi-threading/52015 "2020-12-18T13:40:13Z")

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What’s the best way to synchronize 2 while loops, each running on its own thread? In the example below, loop1 runs 80 times per second while loop2 (blocking/IO) runs 20 times per second. Currently, without any locks/syn…

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## [Unpack or extract elements from array into "list" or "collection" of vectors](https://discourse.julialang.org/t/unpack-or-extract-elements-from-array-into-list-or-collection-of-vectors/52029)

<div class="topic-metadata">

**Author:** [@b1d](https://discourse.julialang.org/u/b1d)\
**Replies:** 4\
**Last updated:** [December 18, 2020, 1:33pm UTC](https://discourse.julialang.org/t/unpack-or-extract-elements-from-array-into-list-or-collection-of-vectors/52029 "2020-12-18T13:33:53Z")

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Hi there, I am not very sure about the appropriate wording. But my problem is as follows: I would like to have intersect(\["a", "b", "c"\], \["b", "c", "d"\], \["c", "d", "e"\]) But I have my vectors as elements in one array…

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