# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1189

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

**Page:** 1190

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## [Understanding \`@eval\` help string and expressions](https://discourse.julialang.org/t/understanding-eval-help-string-and-expressions/72510)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 0\
**Last updated:** [December 3, 2021, 9:38am UTC](https://discourse.julialang.org/t/understanding-eval-help-string-and-expressions/72510 "2021-12-03T09:38:01Z")

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I came across this implementing the rotational cipher in exercism with the very nice help of @tomerarnon. The help for @eval states: @eval \[mod,\] ex Evaluate an expression with values interpolated into it using eval. …

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## [Project nested environments](https://discourse.julialang.org/t/project-nested-environments/72499)

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**Author:** [@jekyllstein](https://discourse.julialang.org/u/jekyllstein)\
**Replies:** 2\
**Last updated:** [December 3, 2021, 7:43am UTC](https://discourse.julialang.org/t/project-nested-environments/72499 "2021-12-03T07:43:52Z")

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I have a package with an examples folder inside of it. I want the examples folder to have its own Project.toml with things like Plots that I don’t want as dependencies in the package itself. I created an environment in t…

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## [ConcurrentCollections.jl: "lock-free" dictionary, queue, etc. for Julia 1.7](https://discourse.julialang.org/t/concurrentcollections-jl-lock-free-dictionary-queue-etc-for-julia-1-7/72501)

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**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 2\
**Last updated:** [December 3, 2021, 5:58am UTC](https://discourse.julialang.org/t/concurrentcollections-jl-lock-free-dictionary-queue-etc-for-julia-1-7/72501 "2021-12-03T05:58:07Z")

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I’m happy to announce a new package ConcurrentCollections.jl that implements a couple of thread-safe collections for Julia 1.7: DualLinkedConcurrentRingQueue DualLinkedQueue LinkedConcurrentRingQueue ConcurrentQueue Co…

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## [FluxML Joins NumFOCUS](https://discourse.julialang.org/t/fluxml-joins-numfocus/72393)

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**Author:** [@dhairyagandhi96](https://discourse.julialang.org/u/dhairyagandhi96)\
**Replies:** 1\
**Last updated:** [December 1, 2021, 6:37pm UTC](https://discourse.julialang.org/t/fluxml-joins-numfocus/72393 "2021-12-01T18:37:45Z")

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We are excited to announce that Flux is partnering with NumFOCUS as an affiliated project. This partnership will help us grow the community and bring in new contributors to realise the goal of a completely differentiable…

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## [Erratic test failure: difference between \]test and include(./test/runtests.jl)](https://discourse.julialang.org/t/erratic-test-failure-difference-between-test-and-include-test-runtests-jl/72342)

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**Author:** [@fipelle](https://discourse.julialang.org/u/fipelle)\
**Replies:** 8\
**Last updated:** [December 3, 2021, 3:28am UTC](https://discourse.julialang.org/t/erratic-test-failure-difference-between-test-and-include-test-runtests-jl/72342 "2021-12-03T03:28:50Z")

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Hi, I am having a strange problem with the tests of one of my packages, MessyTimeSeriesOptim.jl, which is currently under registration. I have cloned the dev branch on my laptop and added the package via Pkg.add(path="…

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## [JULIA matrix norm is different MATLAB](https://discourse.julialang.org/t/julia-matrix-norm-is-different-matlab/72500)

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**Author:** [@Sbeltranj](https://discourse.julialang.org/u/Sbeltranj)\
**Replies:** 6\
**Last updated:** [December 3, 2021, 3:24am UTC](https://discourse.julialang.org/t/julia-matrix-norm-is-different-matlab/72500 "2021-12-03T03:24:42Z")

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Hi, when I calculate the norm of vector a3, I get different values ​​in julia vs MatLab

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## [Leading principal submatrix of Cholesky factor](https://discourse.julialang.org/t/leading-principal-submatrix-of-cholesky-factor/72456)

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**Author:** [@DanielVandH](https://discourse.julialang.org/u/DanielVandH)\
**Replies:** 3\
**Last updated:** [December 3, 2021, 1:03am UTC](https://discourse.julialang.org/t/leading-principal-submatrix-of-cholesky-factor/72456 "2021-12-03T01:03:09Z")

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I have an algorithm that uses only the first k rows and k columns of a Cholesky factor L (i.e., the kth leading principal submatrix L = L\[1:k, 1:k\]). Currently I just extract it after the computation of the whole Cholesk…

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## [\`filter\` with \`eachrow\`](https://discourse.julialang.org/t/filter-with-eachrow/72466)

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**Author:** [@austinbean](https://discourse.julialang.org/u/austinbean)\
**Replies:** 5\
**Last updated:** [December 2, 2021, 11:28pm UTC](https://discourse.julialang.org/t/filter-with-eachrow/72466 "2021-12-02T23:28:02Z")

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Suppose I have an array with two columns. I want to filter the array based on the values of the first column, but would like what is returned by filter to include the second column. This method seems to be missing fro…

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## [Why is ccall syntax?](https://discourse.julialang.org/t/why-is-ccall-syntax/72427)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 8\
**Last updated:** [December 2, 2021, 11:12pm UTC](https://discourse.julialang.org/t/why-is-ccall-syntax/72427 "2021-12-02T23:12:13Z")

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ccall isn’t a function or macro but syntax. Why does it need to be syntax?

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## [BitVector to Bool](https://discourse.julialang.org/t/bitvector-to-bool/72359)

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**Author:** [@jnewbie](https://discourse.julialang.org/u/jnewbie)\
**Replies:** 7\
**Last updated:** [December 2, 2021, 10:30pm UTC](https://discourse.julialang.org/t/bitvector-to-bool/72359 "2021-12-02T22:30:55Z")

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Hi everyone, I have two arrays : x = \[2, 7\] a = \[1,2,5,8,4,9\] I would like to know if x is in a so I do that : x .∈ Ref(a) This returns : 2-element BitVector: 1 0 How can I get the same result but with true a…

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## [We are looking for reviewers for a book about plotting with Julia](https://discourse.julialang.org/t/we-are-looking-for-reviewers-for-a-book-about-plotting-with-julia/72479)

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**Author:** [@Diego\_Javier\_Zea](https://discourse.julialang.org/u/Diego_Javier_Zea)\
**Replies:** 0\
**Last updated:** [December 2, 2021, 5:18pm UTC](https://discourse.julialang.org/t/we-are-looking-for-reviewers-for-a-book-about-plotting-with-julia/72479 "2021-12-02T17:18:26Z")

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Hi! I am writing a book entitled “Interactive Visualization with Julia” for Packt. The book will mainly cover the Plots, Makie, and Gadfly packages, focusing on the first. We are looking for technical reviewers from the…

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## [Makie version of a simple bar graph howto](https://discourse.julialang.org/t/makie-version-of-a-simple-bar-graph-howto/72420)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 6\
**Last updated:** [December 2, 2021, 9:22pm UTC](https://discourse.julialang.org/t/makie-version-of-a-simple-bar-graph-howto/72420 "2021-12-02T21:22:00Z")

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Hello, I am trying to settle on plotting library. I looked into gadfly and very much like the syntax, but the documentation seems lacking, if I am not wrong, it lacks 3d, real time update features. I find makie docume…

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## [Sparse matrix handling (in Julia) and Sparse is Enough in Scaling Transformers paper](https://discourse.julialang.org/t/sparse-matrix-handling-in-julia-and-sparse-is-enough-in-scaling-transformers-paper/72455)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 0\
**Last updated:** [December 2, 2021, 2:53pm UTC](https://discourse.julialang.org/t/sparse-matrix-handling-in-julia-and-sparse-is-enough-in-scaling-transformers-paper/72455 "2021-12-02T14:53:41Z")

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Where does Julia stand regarding sparse matrices for neural networks or otherwise? They have generally relied on dense matrix multiply, until now: The improvement in complexity holds not just asymptotically but yield…

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## [Missing reference with multiple include files](https://discourse.julialang.org/t/missing-reference-with-multiple-include-files/72484)

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**Author:** [@Marco\_Lombardi](https://discourse.julialang.org/u/Marco_Lombardi)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 7:51pm UTC](https://discourse.julialang.org/t/missing-reference-with-multiple-include-files/72484 "2021-12-02T19:51:05Z")

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I am writing some code in VSCode, and I am not sure how what it the best way to split the code in multiple files. As indicated in the Julia documentation, a typical way is to have a single file that includes in the corre…

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## [General registry disappeared from 1.6 after updating to 1.7](https://discourse.julialang.org/t/general-registry-disappeared-from-1-6-after-updating-to-1-7/72485)

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**Author:** [@grahamas](https://discourse.julialang.org/u/grahamas)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 7:23pm UTC](https://discourse.julialang.org/t/general-registry-disappeared-from-1-6-after-updating-to-1-7/72485 "2021-12-02T19:23:52Z")

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I updated to v1.7 yesterday and have been using it without issues since, but I just went back to v1.6 to test something, and found that Pkg doesn’t see the General registry (I also have a personal registry that is unaffe…

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## [Multilayer perceptron with time dependent multidimensional data using Flux](https://discourse.julialang.org/t/multilayer-perceptron-with-time-dependent-multidimensional-data-using-flux/72011)

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**Author:** [@FrootLoops](https://discourse.julialang.org/u/FrootLoops)\
**Replies:** 7\
**Last updated:** [December 2, 2021, 5:20pm UTC](https://discourse.julialang.org/t/multilayer-perceptron-with-time-dependent-multidimensional-data-using-flux/72011 "2021-12-02T17:20:58Z")

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Hi, I have some problems coding a ( multilayer perceptron using Flux. My data is given in the form D\_t = (x\_i, yi)\_{i=1}^n where x\_i is a scalar and y\_i a $3-$dim vector and t=1,\\ldots,T the timesteps. One shold notice …

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## ['inv' Causes Stack Overflow on Julia 1.7.0 and Mac OS](https://discourse.julialang.org/t/inv-causes-stack-overflow-on-julia-1-7-0-and-mac-os/72411)

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**Author:** [@SEA](https://discourse.julialang.org/u/SEA)\
**Replies:** 20\
**Last updated:** [December 2, 2021, 4:53pm UTC](https://discourse.julialang.org/t/inv-causes-stack-overflow-on-julia-1-7-0-and-mac-os/72411 "2021-12-02T16:53:03Z")

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I am running into an odd error when using Julia 1.7.0 on my 2017 Mac Book Pro (Intel i7) on Mac OS 12.01. In particular, executing n = 1000; A = randn(Float32, n, n); inv(A) ERROR: StackOverflowError: With no furthe…

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## [Indexing a fasta file with FASTX.jl](https://discourse.julialang.org/t/indexing-a-fasta-file-with-fastx-jl/72457)

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**Author:** [@Lamma](https://discourse.julialang.org/u/Lamma)\
**Replies:** 1\
**Last updated:** [December 2, 2021, 4:18pm UTC](https://discourse.julialang.org/t/indexing-a-fasta-file-with-fastx-jl/72457 "2021-12-02T16:18:02Z")

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I have been informed it is possible to use FASTX.jl to index a file. However I am struggling to do this. I think I am meant to use FASTA:Record() but am unsure how to pass the data to the function. reader = FASTA.Reader…

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## [NLsolve with StaticArrays](https://discourse.julialang.org/t/nlsolve-with-staticarrays/72465)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 3\
**Last updated:** [December 2, 2021, 4:10pm UTC](https://discourse.julialang.org/t/nlsolve-with-staticarrays/72465 "2021-12-02T16:10:44Z")

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I am wondering if there is a way to make NLsolve work with StaticArrays, because my function is written to take SVector. I thought if I use the keyword argument inplace=false as described in here, I would be able to use…

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## [Parameters in lower, upper and initial\_x in optim](https://discourse.julialang.org/t/parameters-in-lower-upper-and-initial-x-in-optim/72467)

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**Author:** [@Linnea](https://discourse.julialang.org/u/Linnea)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 4:04pm UTC](https://discourse.julialang.org/t/parameters-in-lower-upper-and-initial-x-in-optim/72467 "2021-12-02T16:04:51Z")

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Hi! I have some issues understaning the first two parameters of lower, upper and initial\_x (I understand that the other parameters are selected according to the data ) begin lower\_ = \[0., 0., 10., 1.\] upper\_ = \[1., 1…

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## [When, exactly, is a Julia version released, and how can I tell?](https://discourse.julialang.org/t/when-exactly-is-a-julia-version-released-and-how-can-i-tell/72338)

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**Author:** [@Lilith](https://discourse.julialang.org/u/Lilith)\
**Replies:** 15\
**Last updated:** [December 2, 2021, 3:02pm UTC](https://discourse.julialang.org/t/when-exactly-is-a-julia-version-released-and-how-can-i-tell/72338 "2021-12-02T15:02:27Z")

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I’m developing a package to automatically update Julia, and uses https://julialang-s3.julialang.org/bin/versions.json from Download Julia as an official source for what versions are available. The discourse release annou…

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## [Porting Fortran code, negative indices](https://discourse.julialang.org/t/porting-fortran-code-negative-indices/72386)

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**Author:** [@baptnz](https://discourse.julialang.org/u/baptnz)\
**Replies:** 10\
**Last updated:** [December 2, 2021, 2:32pm UTC](https://discourse.julialang.org/t/porting-fortran-code-negative-indices/72386 "2021-12-02T14:32:04Z")

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I’m porting a low-level program from Fortran, and ideally I would only make minimal changes in the conversion (do loop becoming for kind of thing) to help track down any changes between the two versions. (Later on, once …

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## [How to find the nearest point on a grid?](https://discourse.julialang.org/t/how-to-find-the-nearest-point-on-a-grid/72402)

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**Author:** [@leon](https://discourse.julialang.org/u/leon)\
**Replies:** 10\
**Last updated:** [December 2, 2021, 2:07pm UTC](https://discourse.julialang.org/t/how-to-find-the-nearest-point-on-a-grid/72402 "2021-12-02T14:07:20Z")

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I have a grid defined as Lon = \[-180:0.25:180\]; Lat = \[-90:0.25:90\]; X, Y = meshgrid(Lon, Lat); I have many pairs of station data with corresponding longitude and latitude values and my goal is to find the nearest grid…

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## [(DataFrames.jl) Initially allowing a DataFrame to receive missing](https://discourse.julialang.org/t/dataframes-jl-initially-allowing-a-dataframe-to-receive-missing/72436)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 8\
**Last updated:** [December 2, 2021, 1:33pm UTC](https://discourse.julialang.org/t/dataframes-jl-initially-allowing-a-dataframe-to-receive-missing/72436 "2021-12-02T13:33:07Z")

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According to allowmissing! in DataFrames.jl, it is possible to make a DataFrame “able to receive missing”: julia\> using DataFrames d julia\> df = DataFrame() 0×0 DataFrame julia\> push!(df, (;a=1, b=1.0)) 1×2 DataFrame …

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## [Online Meetup: Distributed computing with Dagger.jl](https://discourse.julialang.org/t/online-meetup-distributed-computing-with-dagger-jl/70491)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 15\
**Last updated:** [December 2, 2021, 1:12pm UTC](https://discourse.julialang.org/t/online-meetup-distributed-computing-with-dagger-jl/70491 "2021-12-02T13:12:34Z")

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Join on Monday 08. November 2021 CET 18:30 organized via meetup Distributed Computing with Dagger.jl ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ A single machine can quickly become too weak to process all your data in time. Dagge…

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## [DimensionMismatch("arrays could not be broadcast to a common size; )](https://discourse.julialang.org/t/dimensionmismatch-arrays-could-not-be-broadcast-to-a-common-size/72448)

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**Author:** [@FH96](https://discourse.julialang.org/u/FH96)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 12:46pm UTC](https://discourse.julialang.org/t/dimensionmismatch-arrays-could-not-be-broadcast-to-a-common-size/72448 "2021-12-02T12:46:47Z")

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I’m trying to write a simple for loop!: for coef in reacions\_to\_test in which “reacions\_to\_test” is 2582-element Vector{Int64} but I face this error : DimensionMismatch("arrays could not be broadcast to a common size…

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## [Build impactful tooling for healthcare analytics at Pumas-AI](https://discourse.julialang.org/t/build-impactful-tooling-for-healthcare-analytics-at-pumas-ai/72442)

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**Author:** [@vjd](https://discourse.julialang.org/u/vjd)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 11:41am UTC](https://discourse.julialang.org/t/build-impactful-tooling-for-healthcare-analytics-at-pumas-ai/72442 "2021-12-02T11:41:02Z")

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Dear Julia Community, Pumas-AI started two years ago with a mission to modernize and improve the efficiency of predictive health analytics, and we are making rapid progress. Check out some of our success stories. Our …

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## [SciML's Stance on the new Julia LTS](https://discourse.julialang.org/t/scimls-stance-on-the-new-julia-lts/72446)

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**Author:** [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Replies:** 0\
**Last updated:** [December 2, 2021, 11:22am UTC](https://discourse.julialang.org/t/scimls-stance-on-the-new-julia-lts/72446 "2021-12-02T11:22:41Z")

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Long-term support is always a balance between spending time developing new exciting features and supporting older Julia versions to allow users to more easily keep up. In the v1.0 LTS era and the Julia v0.x times, SciM…

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## [Interrupting execution](https://discourse.julialang.org/t/interrupting-execution/72434)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 4\
**Last updated:** [December 2, 2021, 11:07am UTC](https://discourse.julialang.org/t/interrupting-execution/72434 "2021-12-02T11:07:14Z")

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I have read that julia only checks for IO and signals etc at certain points in the code. How was I able to interrupt this execution with ctrl-c? Where can I read the details? julia\> function f() while true …

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## [Calling fork](https://discourse.julialang.org/t/calling-fork/72410)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 2\
**Last updated:** [December 2, 2021, 10:18am UTC](https://discourse.julialang.org/t/calling-fork/72410 "2021-12-02T10:18:38Z")

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Julia has more sophisticated multi-processing tools but I want to experiment with some low level options. I expected this code to print the child pid from the parent and 0 from the child but it only prints from the paren…

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