# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1817

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

**Page:** 1818

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## [Output matrix in last (t-1) generation: normal; Indexing the same matrix in this generation: NaNs in the (t-1) column](https://discourse.julialang.org/t/output-matrix-in-last-t-1-generation-normal-indexing-the-same-matrix-in-this-generation-nans-in-the-t-1-column/35059)

<div class="topic-metadata">

**Author:** [@1634](https://discourse.julialang.org/u/1634)\
**Replies:** 2\
**Last updated:** [February 24, 2020, 2:58pm UTC](https://discourse.julialang.org/t/output-matrix-in-last-t-1-generation-normal-indexing-the-same-matrix-in-this-generation-nans-in-the-t-1-column/35059 "2020-02-24T14:58:29Z")

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The only part of this function differring from my previous functional one is adding a variable to be calculated in each generation. NDeme=0.5(Nmax+Nmin)+0.5(Nmax+Nmin)\*sin(2pi\*t/period) #period=12 genetation in setting …

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## [Syntax invalid for "::"](https://discourse.julialang.org/t/syntax-invalid-for/35068)

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**Author:** [@gonced8](https://discourse.julialang.org/u/gonced8)\
**Replies:** 3\
**Last updated:** [February 24, 2020, 2:42pm UTC](https://discourse.julialang.org/t/syntax-invalid-for/35068 "2020-02-24T14:42:44Z")

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I’m new to Julia and I’m trying to use this package: However, after adding it with pkg add GitHub - interplanetary-robot/SigmoidNumbers: Sigmoid Numbers for Julia when I type using SigmoidNumbers I get the foll…

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## [PackageCompiler for having a simple .exe?](https://discourse.julialang.org/t/packagecompiler-for-having-a-simple-exe/35071)

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**Author:** [@Darione](https://discourse.julialang.org/u/Darione)\
**Replies:** 4\
**Last updated:** [February 24, 2020, 2:39pm UTC](https://discourse.julialang.org/t/packagecompiler-for-having-a-simple-exe/35071 "2020-02-24T14:39:22Z")

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Hello, i am looking for a PackageCompiler instruction for humans, because it seems to me that there are a lot of links in internet but it is difficult to find the most simple case : own simple script that print something…

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## [\[ANN\] LightGraphs 1.3.1, and the upcoming roadmap](https://discourse.julialang.org/t/ann-lightgraphs-1-3-1-and-the-upcoming-roadmap/35063)

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**Author:** [@anon94023334](https://discourse.julialang.org/u/anon94023334)\
**Replies:** 0\
**Last updated:** [February 24, 2020, 6:10am UTC](https://discourse.julialang.org/t/ann-lightgraphs-1-3-1-and-the-upcoming-roadmap/35063 "2020-02-24T06:10:06Z")

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Hi all, Minor announcement: we’ve released LightGraphs v1.3.1 with some bug and documentation fixes, a bit of new functionality, and a couple of fairly significant performance improvements. The bigger part of this relea…

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## [Dates: picosecond, femtosecond, attosecond period](https://discourse.julialang.org/t/dates-picosecond-femtosecond-attosecond-period/35066)

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**Author:** [@larschrj](https://discourse.julialang.org/u/larschrj)\
**Replies:** 2\
**Last updated:** [February 24, 2020, 10:39am UTC](https://discourse.julialang.org/t/dates-picosecond-femtosecond-attosecond-period/35066 "2020-02-24T10:39:08Z")

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Is there any argument against adding picosecond, femtosecond, attosecond periods to Dates? (e.g. performance or bloating stdlib code) Otherwise I’d like to do so.

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## [Of general interest: SciPy's solution to the two-language problem is](https://discourse.julialang.org/t/of-general-interest-scipys-solution-to-the-two-language-problem-is/35051)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 5\
**Last updated:** [February 24, 2020, 9:34am UTC](https://discourse.julialang.org/t/of-general-interest-scipys-solution-to-the-two-language-problem-is/35051 "2020-02-24T09:34:10Z")

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… 5 languages. :wink: Link to article Lest someone feels the need to correct me: this is tongue in cheek. I do recognize the need to wrap established libraries. The article does not actually say how much of “fast langu…

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## [\[ANN\] SatelliteToolbox.jl v0.7.0 =\> IGRFv13 and RV to TLE conversion](https://discourse.julialang.org/t/ann-satellitetoolbox-jl-v0-7-0-igrfv13-and-rv-to-tle-conversion/35060)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 0\
**Last updated:** [February 24, 2020, 1:42am UTC](https://discourse.julialang.org/t/ann-satellitetoolbox-jl-v0-7-0-igrfv13-and-rv-to-tle-conversion/35060 "2020-02-24T01:42:51Z")

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Hi! I have just registered a new version of SatelliteToolbox.jl (v0.7.0). It was supposed to be a somewhat small release. However, I decided to make a huge change in some parts because I was using a very old way of pro…

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## [\[ANN\] New version of package PseudoArcLengthContinuation.jl](https://discourse.julialang.org/t/ann-new-version-of-package-pseudoarclengthcontinuation-jl/34604)

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**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 1\
**Last updated:** [February 23, 2020, 10:43pm UTC](https://discourse.julialang.org/t/ann-new-version-of-package-pseudoarclengthcontinuation-jl/34604 "2020-02-23T22:43:11Z")

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Dear All, After roughly one year, I am writing this post to report a new version of my package PseudoArcLengthContinuation.jl. The focus of this new version is twofold, namely the computation of bifurcations (localizati…

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## [NEP-PACK 1.0: A julia package for nonlinear eigenvalue problems](https://discourse.julialang.org/t/nep-pack-1-0-a-julia-package-for-nonlinear-eigenvalue-problems/31342)

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**Author:** [@jarl](https://discourse.julialang.org/u/jarl)\
**Replies:** 19\
**Last updated:** [February 23, 2020, 10:03pm UTC](https://discourse.julialang.org/t/nep-pack-1-0-a-julia-package-for-nonlinear-eigenvalue-problems/31342 "2020-02-23T22:03:30Z")

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We are proud to announce version 1.0 of NEP-PACK - a Julia package for nonlinear eigenvalue problems with eigenvalue nonlinearities. The package is released with an open-source license. The package makes full use of the …

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## [Taking panel and temporal data seriously](https://discourse.julialang.org/t/taking-panel-and-temporal-data-seriously/35050)

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**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 11\
**Last updated:** [February 23, 2020, 8:24pm UTC](https://discourse.julialang.org/t/taking-panel-and-temporal-data-seriously/35050 "2020-02-23T20:24:13Z")

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This discussion is about how to best implement a context for tabular data that generalizes to cross-sectional and temporal dimensions. For example, subject period value 1 1 0 1 2 3 1 3 …

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## [Condition number for a sparse matrix](https://discourse.julialang.org/t/condition-number-for-a-sparse-matrix/35049)

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**Author:** [@AhmedAlreweny](https://discourse.julialang.org/u/AhmedAlreweny)\
**Replies:** 0\
**Last updated:** [February 23, 2020, 3:27pm UTC](https://discourse.julialang.org/t/condition-number-for-a-sparse-matrix/35049 "2020-02-23T15:27:24Z")

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Hello, I am trying to solve a big sparse linear system using the direct solver. I get accurate results most of the times. However, sometimes the matrix is ill-conditioned and I get unreasonable solution. In this contex…

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## [How can I reduce memory allocation and execution time while ray tracing using VoxelRayTracers package?](https://discourse.julialang.org/t/how-can-i-reduce-memory-allocation-and-execution-time-while-ray-tracing-using-voxelraytracers-package/34971)

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**Author:** [@Manu\_Francis](https://discourse.julialang.org/u/Manu_Francis)\
**Replies:** 4\
**Last updated:** [February 23, 2020, 9:55am UTC](https://discourse.julialang.org/t/how-can-i-reduce-memory-allocation-and-execution-time-while-ray-tracing-using-voxelraytracers-package/34971 "2020-02-23T09:55:16Z")

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Hi, I am trying to use VoxelRayTracers.jl package to trace a ray through cubic voxels. I want to improve the performance of ray tracing by reducing execution time because in my application I have to use many rays in th…

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## [Associating information to a type](https://discourse.julialang.org/t/associating-information-to-a-type/34937)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 4\
**Last updated:** [February 23, 2020, 6:05am UTC](https://discourse.julialang.org/t/associating-information-to-a-type/34937 "2020-02-23T06:05:21Z")

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Consider struct Foo end @is\_friend(Foo, "Bob") @is\_friend(Foo, "Tim") println(friends\_of(Foo)) Is there a clean way of implementing @is\_friend and friends\_of to return \["Bob", "Tim"\]? One solution is with a global D…

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## [Error while installing NEOS.jl](https://discourse.julialang.org/t/error-while-installing-neos-jl/35041)

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**Author:** [@Deb\_Midya](https://discourse.julialang.org/u/Deb_Midya)\
**Replies:** 3\
**Last updated:** [February 23, 2020, 5:09am UTC](https://discourse.julialang.org/t/error-while-installing-neos-jl/35041 "2020-02-23T05:09:03Z")

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I’m using Julia-1.3.1 on Windows 64. To install NEOS.jl, I’ve used the followings: Julia\>import Pkg Julia\>Pkg.add(“NEOS.jl”) ERROR: The following package names could not be resolved: NOES.jl (not found in project, m…

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## [\[ANN\] PlusMinus.jl](https://discourse.julialang.org/t/ann-plusminus-jl/35033)

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**Author:** [@tbeason](https://discourse.julialang.org/u/tbeason)\
**Replies:** 6\
**Last updated:** [February 23, 2020, 1:28am UTC](https://discourse.julialang.org/t/ann-plusminus-jl/35033 "2020-02-23T01:28:11Z")

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Got irked the other day that 2 ± 1 was not already a thing, so I made it a thing. PlusMinus.jl gives you that. ±(x,y) = (x-y, x+y) That is all.

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## [How to properly unwrap nested structs to access internals?](https://discourse.julialang.org/t/how-to-properly-unwrap-nested-structs-to-access-internals/35003)

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**Author:** [@tlnagy](https://discourse.julialang.org/u/tlnagy)\
**Replies:** 4\
**Last updated:** [February 22, 2020, 8:39pm UTC](https://discourse.julialang.org/t/how-to-properly-unwrap-nested-structs-to-access-internals/35003 "2020-02-22T20:39:33Z")

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Say I have the following architecture: struct AArray \<: AbstractArray arr end struct BArray \<: AbstractArray data::AbstractArray end struct CArray \<: AbstractArray cool\_mapping::Dict end Where I can have…

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## [How to run tasks in parallel?](https://discourse.julialang.org/t/how-to-run-tasks-in-parallel/35018)

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**Author:** [@Skoffer](https://discourse.julialang.org/u/Skoffer)\
**Replies:** 6\
**Last updated:** [February 22, 2020, 8:25pm UTC](https://discourse.julialang.org/t/how-to-run-tasks-in-parallel/35018 "2020-02-22T20:25:40Z")

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I am trying to understand how to work properly with multithreading. Currently, I am on julia 1.3.1, which is started with JULIA\_NUM\_THREADS=4 julia and trying to simulate simple embarrassingly parallel task. f(x) = sum(…

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## [Error building \`PackageCompiler\`:](https://discourse.julialang.org/t/error-building-packagecompiler/35019)

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**Author:** [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Replies:** 2\
**Last updated:** [February 22, 2020, 7:15pm UTC](https://discourse.julialang.org/t/error-building-packagecompiler/35019 "2020-02-22T19:15:31Z")

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I recently upgraded my setup and reinstalled Julia. Package compiler will not build because it’s looking for 7z.exe in the Julia bin folder instead of libexec (on Windows). (v1.3) pkg\> add PackageCompiler Resolving pac…

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## [\[ANN\] Jusdl.jl v0.1.0 - Julia Based System Description Language](https://discourse.julialang.org/t/ann-jusdl-jl-v0-1-0-julia-based-system-description-language/34727)

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**Author:** [@zekeriya.sari](https://discourse.julialang.org/u/zekeriya.sari)\
**Replies:** 9\
**Last updated:** [February 22, 2020, 6:14pm UTC](https://discourse.julialang.org/t/ann-jusdl-jl-v0-1-0-julia-based-system-description-language/34727 "2020-02-22T18:14:06Z")

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I would like to announce the first release of Jusdl (Julia-Based System Description Language) that focusses on effective system simulations together with online and offline data analysis. In Jusdl, it is possible to simu…

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## [Pkg new telemetry options](https://discourse.julialang.org/t/pkg-new-telemetry-options/35023)

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**Author:** [@longemen3000](https://discourse.julialang.org/u/longemen3000)\
**Replies:** 0\
**Last updated:** [February 22, 2020, 5:44pm UTC](https://discourse.julialang.org/t/pkg-new-telemetry-options/35023 "2020-02-22T17:44:57Z")

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This is mainly a placeholder to put information on the new pkg telemetry protocol

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## [\`eachrow\` over Array{Any, 2} does not return rows, why?](https://discourse.julialang.org/t/eachrow-over-array-any-2-does-not-return-rows-why/34601)

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**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 23\
**Last updated:** [February 22, 2020, 3:45pm UTC](https://discourse.julialang.org/t/eachrow-over-array-any-2-does-not-return-rows-why/34601 "2020-02-22T15:45:57Z")

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I use Julia often, but mostly JuMP. I have incentivized the use of Julia in my laboratory. Today, one of my laboratory colleagues has said to me he used Julia to make a small program, and while he overall liked the langu…

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## [Is there a more elegant solution than \`sortperm(sortperm(...))\`](https://discourse.julialang.org/t/is-there-a-more-elegant-solution-than-sortperm-sortperm/35015)

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**Author:** [@pfarndt](https://discourse.julialang.org/u/pfarndt)\
**Replies:** 6\
**Last updated:** [February 22, 2020, 3:38pm UTC](https://discourse.julialang.org/t/is-there-a-more-elegant-solution-than-sortperm-sortperm/35015 "2020-02-22T15:38:36Z")

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Say I have two vectors of identifiers - the second one being a shuffled version of the first one - like this: using Random, Test a = \[ randstring(5) for \_ in 1:20 \] b = shuffle(a) and now I want to loop through a such …

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## [Metaprogramming using Meta.parse + eval](https://discourse.julialang.org/t/metaprogramming-using-meta-parse-eval/35014)

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**Author:** [@terdmann](https://discourse.julialang.org/u/terdmann)\
**Replies:** 5\
**Last updated:** [February 22, 2020, 1:24pm UTC](https://discourse.julialang.org/t/metaprogramming-using-meta-parse-eval/35014 "2020-02-22T13:24:22Z")

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Here’s an example of what I am trying to do: src = \["function f(x) x^2 end", "function f(x) x^3 end", "function f(x) x^4 end"\] for s in src eval(Meta.parse(s)) @show f(2) end This does not wor…

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## [How to properly reference binary dependencies during builds with BinaryBuilder?](https://discourse.julialang.org/t/how-to-properly-reference-binary-dependencies-during-builds-with-binarybuilder/35008)

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**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 2\
**Last updated:** [February 22, 2020, 11:32am UTC](https://discourse.julialang.org/t/how-to-properly-reference-binary-dependencies-during-builds-with-binarybuilder/35008 "2020-02-22T11:32:30Z")

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I am trying to wrap a library with BinaryBuilder that depends on libz. If I use the wizard, specifying “Zlib” as a dependency, I actually do get all the library files from zlib in my workspace that I need. However, for m…

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## [Dispatching on function types?](https://discourse.julialang.org/t/dispatching-on-function-types/34983)

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**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 1\
**Last updated:** [February 22, 2020, 9:37am UTC](https://discourse.julialang.org/t/dispatching-on-function-types/34983 "2020-02-22T09:37:00Z")

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Motivating problem: julia\> struct MappedElement{F \<: Function,T \<: Real} \<: Real x::T fx::T MappedElement{F}(x::T, fx::T) where {F,T} = new{F,T}(x, fx) MappedElement{F}(x, fx…

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## [CUDA verbose mode off](https://discourse.julialang.org/t/cuda-verbose-mode-off/34930)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 1\
**Last updated:** [February 20, 2020, 6:42pm UTC](https://discourse.julialang.org/t/cuda-verbose-mode-off/34930 "2020-02-20T18:42:02Z")

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Hi folks, sometimes I find that my CUDA functions display this message ┌ Warning: Performing scalar operations on GPU arrays: This is very slow, consider disallowing these operations with \`allowscalar(false)\` └ @ GPUAr…

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## [Is it possible to have a field CholeskyPivoted and update it?](https://discourse.julialang.org/t/is-it-possible-to-have-a-field-choleskypivoted-and-update-it/34946)

<div class="topic-metadata">

**Author:** [@kai](https://discourse.julialang.org/u/kai)\
**Replies:** 4\
**Last updated:** [February 22, 2020, 6:07am UTC](https://discourse.julialang.org/t/is-it-possible-to-have-a-field-choleskypivoted-and-update-it/34946 "2020-02-22T06:07:46Z")

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My function performs cholesky decomposition on a matrix V many many times, so I want to create a field Vchol in my model struct m to avoid repeated allocation. So my type looks like struct m{T \<:Real} ... V::Mat…

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## [\[Bug?\] JuMP.read\_from\_file+Cbc gives infeasible, just Cbc gives feasible](https://discourse.julialang.org/t/bug-jump-read-from-file-cbc-gives-infeasible-just-cbc-gives-feasible/34990)

<div class="topic-metadata">

**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 3\
**Last updated:** [February 22, 2020, 4:50am UTC](https://discourse.julialang.org/t/bug-jump-read-from-file-cbc-gives-infeasible-just-cbc-gives-feasible/34990 "2020-02-22T04:50:46Z")

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I found the problem without using the read\_from\_file (i.e., it arose from a model built inside Julia, but the code to generate the model is long) in the corner case where the model is kinda empty but not really. The mode…

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## [Debugger.jl halted on the line of JSON.parse()](https://discourse.julialang.org/t/debugger-jl-halted-on-the-line-of-json-parse/34988)

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**Author:** [@zhangliye](https://discourse.julialang.org/u/zhangliye)\
**Replies:** 4\
**Last updated:** [February 22, 2020, 4:05am UTC](https://discourse.julialang.org/t/debugger-jl-halted-on-the-line-of-json-parse/34988 "2020-02-22T04:05:15Z")

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I tested Debugger using Julia1.3 and Julia 1.2. I use command n to debug line by line. When it encounter the line using JSON.jl package. VS running a long time and halted there, and can not go to the next line. The demo…

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## [The Julia Language selected to be a part of GSoC 2020](https://discourse.julialang.org/t/the-julia-language-selected-to-be-a-part-of-gsoc-2020/34944)

<div class="topic-metadata">

**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 2\
**Last updated:** [February 22, 2020, 1:52am UTC](https://discourse.julialang.org/t/the-julia-language-selected-to-be-a-part-of-gsoc-2020/34944 "2020-02-22T01:52:22Z")

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Hey all! We are delighted to announce that the Julia Langauge has been accepted into Google’s Summer of Code Program once again. In this program, University students will: Spend their summer break writing code and lear…

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