# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1099

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

**Page:** 1100

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## [How to solve ERROR: IOError: could not spawn Electron?](https://discourse.julialang.org/t/how-to-solve-error-ioerror-could-not-spawn-electron/77649)

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**Author:** [@realkrantz](https://discourse.julialang.org/u/realkrantz)\
**Replies:** 10\
**Last updated:** [March 11, 2022, 11:18am UTC](https://discourse.julialang.org/t/how-to-solve-error-ioerror-could-not-spawn-electron/77649 "2022-03-11T11:18:24Z")

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\#This works: using VegaLite, VegaDatasets, ElectronDisplay dataset("cars") |\> @vlplot(:point, x=:Acceleration, y=:Miles\_per\_Gallon, color=:Origin) #But this does not work: using DataFrames, ElectronDisplay df = DataFr…

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## [Dynamicly change the Base.show methods with using macro?](https://discourse.julialang.org/t/dynamicly-change-the-base-show-methods-with-using-macro/77665)

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**Author:** [@Brian1](https://discourse.julialang.org/u/Brian1)\
**Replies:** 6\
**Last updated:** [March 11, 2022, 10:49am UTC](https://discourse.julialang.org/t/dynamicly-change-the-base-show-methods-with-using-macro/77665 "2022-03-11T10:49:47Z")

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There is two methods showing Float64: t1show(io,x::Float64)=begin if x\<1e-3 xshow=x/1e-4 |\> x-\>round(2,digits=2) print(io,string(xshow)\*" bp") else print(io,string(x)) end end t2show…

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## [Rss description from page body in Franklin](https://discourse.julialang.org/t/rss-description-from-page-body-in-franklin/75936)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 1\
**Last updated:** [March 11, 2022, 8:33am UTC](https://discourse.julialang.org/t/rss-description-from-page-body-in-franklin/75936 "2022-03-11T08:33:29Z")

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I understand that Franklin.jl only adds a page to the RSS feed if the relevant page variable is set (rss for short), which then provides the description. Would it be possible to auto-generate this from the first N words…

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## [Obtaining parameter types for a function](https://discourse.julialang.org/t/obtaining-parameter-types-for-a-function/62169)

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**Author:** [@harris-chris](https://discourse.julialang.org/u/harris-chris)\
**Replies:** 13\
**Last updated:** [March 11, 2022, 7:31am UTC](https://discourse.julialang.org/t/obtaining-parameter-types-for-a-function/62169 "2022-03-11T07:31:22Z")

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Hello all, Is there any way to obtain the parameter types for a given method? For example, if I have function f(x::Int64) x end, is there a way to recover the type of parameter x? I realize that generic methods may make…

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## [What's the problem with this simple multi-thread code?](https://discourse.julialang.org/t/whats-the-problem-with-this-simple-multi-thread-code/77626)

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**Author:** [@photor](https://discourse.julialang.org/u/photor)\
**Replies:** 17\
**Last updated:** [March 11, 2022, 4:50am UTC](https://discourse.julialang.org/t/whats-the-problem-with-this-simple-multi-thread-code/77626 "2022-03-11T04:50:18Z")

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I defined a very simple function to compute the dot product, which is supposed to be equivalent to dot(x,A,y) in the package LinearAlgebra. For performance, I use Threads.@threads to make it multi-thread: using Benchmar…

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## [Tullio - multiline syntax - Soft or hard local scope?](https://discourse.julialang.org/t/tullio-multiline-syntax-soft-or-hard-local-scope/77616)

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**Author:** [@Emmanuel-R8](https://discourse.julialang.org/u/Emmanuel-R8)\
**Replies:** 6\
**Last updated:** [March 11, 2022, 2:51am UTC](https://discourse.julialang.org/t/tullio-multiline-syntax-soft-or-hard-local-scope/77616 "2022-03-11T02:51:04Z")

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I have a block of code using Tullio with a begin ... end syntax. I discovered that, within the block, only = can be used. No := will be acctepted. My problem now is that on execution that patch\_mean is an unknown symbo…

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## [Vectorizing negation?](https://discourse.julialang.org/t/vectorizing-negation/77721)

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**Author:** [@jecs](https://discourse.julialang.org/u/jecs)\
**Replies:** 7\
**Last updated:** [March 11, 2022, 1:05am UTC](https://discourse.julialang.org/t/vectorizing-negation/77721 "2022-03-11T01:05:31Z")

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Hi, I was wondering if it’s possible at all to negate elements in a collection using vectorization. So something like -.(1,2,3). I tried this in Julia, but it doesn’t seem to be accepted syntax. I could use -1 .\* (1,2,3…

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## [How to promote a factorization?](https://discourse.julialang.org/t/how-to-promote-a-factorization/77715)

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**Author:** [@ctkelley](https://discourse.julialang.org/u/ctkelley)\
**Replies:** 5\
**Last updated:** [March 10, 2022, 10:12pm UTC](https://discourse.julialang.org/t/how-to-promote-a-factorization/77715 "2022-03-10T22:12:29Z")

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I’m trying to promote an LU factorization in one precision to a higher precision. The permutation vector does not map correctly and I can’t figure out why. Any ideas? MWE: julia\> A=rand(Float32,3,3); julia\> AF=lu!(…

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## [Infeasible or unbounded model](https://discourse.julialang.org/t/infeasible-or-unbounded-model/77653)

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**Author:** [@dires](https://discourse.julialang.org/u/dires)\
**Replies:** 6\
**Last updated:** [March 10, 2022, 10:04pm UTC](https://discourse.julialang.org/t/infeasible-or-unbounded-model/77653 "2022-03-10T22:04:26Z")

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I got this message for my optimization problem can anybody help me how to resolve this? "Result index of attribute MathOptInterface.ObjectiveValue(1) out of bounds. There are currently 0 solution(s) in the model. check…

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## [Generate a random number exclusive on both sides: smaller# \< x \< larger#?](https://discourse.julialang.org/t/generate-a-random-number-exclusive-on-both-sides-smaller-x-larger/77719)

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**Author:** [@Bob\_Bass](https://discourse.julialang.org/u/Bob_Bass)\
**Replies:** 6\
**Last updated:** [March 10, 2022, 10:02pm UTC](https://discourse.julialang.org/t/generate-a-random-number-exclusive-on-both-sides-smaller-x-larger/77719 "2022-03-10T22:02:53Z")

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Hi. How can I generate a random real number between -3 and 3 that is exclusive on both sides? Thank you.

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## [Data Container like in Matlab Structure Arrays](https://discourse.julialang.org/t/data-container-like-in-matlab-structure-arrays/77691)

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**Author:** [@Bozaga\_Murat](https://discourse.julialang.org/u/Bozaga_Murat)\
**Replies:** 5\
**Last updated:** [March 10, 2022, 7:27pm UTC](https://discourse.julialang.org/t/data-container-like-in-matlab-structure-arrays/77691 "2022-03-10T19:27:01Z")

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Hello everybody, I am master student in simulations in germany. I am newcomer from Matlab because the performance of Matlab is too low for my discretization in the additive manufactaring. Julia is really nice, but I ha…

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## [PNGFiles load from stream doesn't work with TCPSocket](https://discourse.julialang.org/t/pngfiles-load-from-stream-doesnt-work-with-tcpsocket/77713)

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**Author:** [@joeynelson](https://discourse.julialang.org/u/joeynelson)\
**Replies:** 0\
**Last updated:** [March 10, 2022, 7:08pm UTC](https://discourse.julialang.org/t/pngfiles-load-from-stream-doesnt-work-with-tcpsocket/77713 "2022-03-10T19:08:44Z")

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I have a simple server that just serves up a raw PNG file any client that connects. In Julia I wrote the following function to attempt to load that image. function ReadTeensyImage(server) sock = Sockets.connect(ser…

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## [Need Help with accented characters](https://discourse.julialang.org/t/need-help-with-accented-characters/77699)

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**Author:** [@folleyz](https://discourse.julialang.org/u/folleyz)\
**Replies:** 5\
**Last updated:** [March 10, 2022, 6:58pm UTC](https://discourse.julialang.org/t/need-help-with-accented-characters/77699 "2022-03-10T18:58:56Z")

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Hello, i’m new in Julia and i’m facing a problem with accented characters like ã or á. I loaded a dataframe from my SQLServer Database using ODBC and i’m having trouble to Uppercase the column “unidade”, i think this oc…

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## [OpenCV VideoWriter\_fourcc error](https://discourse.julialang.org/t/opencv-videowriter-fourcc-error/77710)

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**Author:** [@cirobr](https://discourse.julialang.org/u/cirobr)\
**Replies:** 0\
**Last updated:** [March 10, 2022, 6:22pm UTC](https://discourse.julialang.org/t/opencv-videowriter-fourcc-error/77710 "2022-03-10T18:22:43Z")

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Hello, Running the below instructions as preparation for writing a sequence of images to a video file with OpenCV as framework: using OpenCV; const cv = OpenCV fourcc = cv.VideoWriter\_fourcc(\*'XVID') The instruction …

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## [Checking if a vector of structs is contiguous in memory](https://discourse.julialang.org/t/checking-if-a-vector-of-structs-is-contiguous-in-memory/2759)

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**Author:** [@vipstar](https://discourse.julialang.org/u/vipstar)\
**Replies:** 10\
**Last updated:** [March 10, 2022, 5:45pm UTC](https://discourse.julialang.org/t/checking-if-a-vector-of-structs-is-contiguous-in-memory/2759 "2022-03-10T17:45:34Z")

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Hi, So I have an vector of tuples of floats, i.e.: Array{Tuple{Float64,Float64},1}(). I know that tuples are immutables and so theoretically this array should be contiguous in memory and there should be no pointers in t…

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## [Struct of singleton Abstract types performance](https://discourse.julialang.org/t/struct-of-singleton-abstract-types-performance/77679)

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**Author:** [@filchristou](https://discourse.julialang.org/u/filchristou)\
**Replies:** 6\
**Last updated:** [March 10, 2022, 5:37pm UTC](https://discourse.julialang.org/t/struct-of-singleton-abstract-types-performance/77679 "2022-03-10T17:37:33Z")

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I understand Julia not being fast when using structs of abstract types and I know that there is no such thing as singleton abstract types. However I would hope that it would be different when using Abstract types of whic…

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## [Distributed Julia in the cloud](https://discourse.julialang.org/t/distributed-julia-in-the-cloud/77627)

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**Author:** [@niczky12](https://discourse.julialang.org/u/niczky12)\
**Replies:** 18\
**Last updated:** [March 10, 2022, 4:06pm UTC](https://discourse.julialang.org/t/distributed-julia-in-the-cloud/77627 "2022-03-10T16:06:13Z")

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I know that JuliaPro is doing a good job of running Julia across a cluster in Azure. However, I have not seen an easy to follow guide to spin up a cluster in AWS/GCP/Azure without the paid version. I am really fed up wi…

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## [What is Wijmo and why am I being asked to create a license?](https://discourse.julialang.org/t/what-is-wijmo-and-why-am-i-being-asked-to-create-a-license/77602)

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**Author:** [@Soldalma](https://discourse.julialang.org/u/Soldalma)\
**Replies:** 6\
**Last updated:** [March 10, 2022, 3:07pm UTC](https://discourse.julialang.org/t/what-is-wijmo-and-why-am-i-being-asked-to-create-a-license/77602 "2022-03-10T15:07:14Z")

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I use the Open Preview context menu item in the VSCode Explorer to look at the contents of DataFrames saved in CSV format. Everything was working fine until this morning. Now when I click on Open Preview the dataframe co…

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## [Using Julia on Git bash](https://discourse.julialang.org/t/using-julia-on-git-bash/24413)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 9\
**Last updated:** [March 10, 2022, 1:48pm UTC](https://discourse.julialang.org/t/using-julia-on-git-bash/24413 "2022-03-10T13:48:02Z")

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I find windows powershell pretty buggy, and sometimes it breaks when trying to open Vim and the key press - display loop gets messed up. Git bash has always worked for me when ssh-ing. Is there a step by step guide to m…

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## [How to shift the ticks of a heat map?](https://discourse.julialang.org/t/how-to-shift-the-ticks-of-a-heat-map/77682)

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**Author:** [@Dan\_Micsa](https://discourse.julialang.org/u/Dan_Micsa)\
**Replies:** 0\
**Last updated:** [March 10, 2022, 1:10pm UTC](https://discourse.julialang.org/t/how-to-shift-the-ticks-of-a-heat-map/77682 "2022-03-10T13:10:42Z")

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I try to see a correlation matrix in Julia.Plots and the axis are shifted half tick away from where I expect them. using Plots using PlotThemes rho = cor(Return1D) ticks\_ = (1:1:length(tickers)+1, tickers) size\_ = len…

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## [Removing precompilation leads to lower allocations!?](https://discourse.julialang.org/t/removing-precompilation-leads-to-lower-allocations/73621)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 5\
**Last updated:** [March 10, 2022, 12:52pm UTC](https://discourse.julialang.org/t/removing-precompilation-leads-to-lower-allocations/73621 "2022-03-10T12:52:27Z")

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In one of my packages I tried to lower import times, so I added a couple of typical usage examples in a “precompile” function. Something like function \_my\_precompile() # my "typical use case" code ... end functi…

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## [Is Interact package dead?](https://discourse.julialang.org/t/is-interact-package-dead/77572)

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**Author:** [@pao](https://discourse.julialang.org/u/pao)\
**Replies:** 8\
**Last updated:** [March 10, 2022, 12:10pm UTC](https://discourse.julialang.org/t/is-interact-package-dead/77572 "2022-03-10T12:10:31Z")

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I see that it is impossible lo “add Interact” to both “v16.5” (LTS) and to “v17.2” … Please let me know … Thanks !!

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## [Communication between two threads in Julia without blocking](https://discourse.julialang.org/t/communication-between-two-threads-in-julia-without-blocking/77637)

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**Author:** [@Tine](https://discourse.julialang.org/u/Tine)\
**Replies:** 4\
**Last updated:** [March 10, 2022, 11:23am UTC](https://discourse.julialang.org/t/communication-between-two-threads-in-julia-without-blocking/77637 "2022-03-10T11:23:16Z")

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Hi! I am building a system that consist of multiple threads doing different work. For the purpose of this post, I am simplifying the code. My system: using ThreadPools function work() (timer) -\> begin sto…

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## [Locking a specific value using ReentrantLock](https://discourse.julialang.org/t/locking-a-specific-value-using-reentrantlock/77673)

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**Author:** [@Tine](https://discourse.julialang.org/u/Tine)\
**Replies:** 5\
**Last updated:** [March 10, 2022, 10:57am UTC](https://discourse.julialang.org/t/locking-a-specific-value-using-reentrantlock/77673 "2022-03-10T10:57:36Z")

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Is it possible to lock a specific value using ReentrantLock() Example: struct Person name::String age::Int64 number::Int64 end nancy = Person("Nancy", 34, 12345678) # What I do now lk = ReentrantLock() lo…

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## [Access the xticks of a Plots.jl plot](https://discourse.julialang.org/t/access-the-xticks-of-a-plots-jl-plot/77676)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 1\
**Last updated:** [March 10, 2022, 9:31am UTC](https://discourse.julialang.org/t/access-the-xticks-of-a-plots-jl-plot/77676 "2022-03-10T09:31:36Z")

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How can I access the current xticks of a figure created by Plots.jl?

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## [How to represent a value as a syntactically correct string](https://discourse.julialang.org/t/how-to-represent-a-value-as-a-syntactically-correct-string/77667)

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**Author:** [@andrey2185](https://discourse.julialang.org/u/andrey2185)\
**Replies:** 1\
**Last updated:** [March 10, 2022, 8:39am UTC](https://discourse.julialang.org/t/how-to-represent-a-value-as-a-syntactically-correct-string/77667 "2022-03-10T08:39:56Z")

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Hello, how to represent a simple value as a syntactically correct string? for example, this is i do represent(s::Symbol)::String = "Symbol(\\"$s\\")" represent(:abc) # -\> "Symbol("abs")" # but have a bug Symbol("\\\\\\"a…

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## [Reactive plot in Pluto or Jupyter?](https://discourse.julialang.org/t/reactive-plot-in-pluto-or-jupyter/77654)

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**Author:** [@maajdl](https://discourse.julialang.org/u/maajdl)\
**Replies:** 2\
**Last updated:** [March 10, 2022, 7:58am UTC](https://discourse.julialang.org/t/reactive-plot-in-pluto-or-jupyter/77654 "2022-03-10T07:58:19Z")

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Hello, This is what I would like to do in Pluto or JupyterLab: Create a plot Click on this plot Get the coordinates into some variables (binding) Modify the plot To be run in Pluto or Jupyter Would that be possi…

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## [Lanczos tridiagonalization algorithm in Julia?](https://discourse.julialang.org/t/lanczos-tridiagonalization-algorithm-in-julia/77085)

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**Author:** [@falbarelli](https://discourse.julialang.org/u/falbarelli)\
**Replies:** 19\
**Last updated:** [March 10, 2022, 7:15am UTC](https://discourse.julialang.org/t/lanczos-tridiagonalization-algorithm-in-julia/77085 "2022-03-10T07:15:29Z")

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Hi everyone! I have been looking for an implementation of Lanczos algorithm in Julia, but to my surprise I haven’t found anything obvious! I need the actual tridiagonalization, i.e. the tridiagonal matrix T and the uni…

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## [VSCode extension not seeing my julia 1.7.1 install](https://discourse.julialang.org/t/vscode-extension-not-seeing-my-julia-1-7-1-install/74267)

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**Author:** [@quailman1031](https://discourse.julialang.org/u/quailman1031)\
**Replies:** 10\
**Last updated:** [March 10, 2022, 6:42am UTC](https://discourse.julialang.org/t/vscode-extension-not-seeing-my-julia-1-7-1-install/74267 "2022-03-10T06:42:43Z")

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I can not get the VS Code Julia extension (version 1.5.8) to find my installation of the most recent Julia version (1.7.1). Specifying the execution path does not help. It seems to work for other Julia versions (Julia 1.…

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## [LU decomposition in Julia](https://discourse.julialang.org/t/lu-decomposition-in-julia/77664)

<div class="topic-metadata">

**Author:** [@lbc546](https://discourse.julialang.org/u/lbc546)\
**Replies:** 7\
**Last updated:** [March 10, 2022, 3:32am UTC](https://discourse.julialang.org/t/lu-decomposition-in-julia/77664 "2022-03-10T03:32:46Z")

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Trying to rewrite the lu\_nopivot from this answer matrix - Perform LU decomposition without pivoting in MATLAB - Stack Overflow into JULIA and use only one loop. The julia code I wrote using LinearAlgebra function lu\_n…

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