# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1892

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

**Page:** 1893

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## [Output of functions](https://discourse.julialang.org/t/output-of-functions/30492)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 5\
**Last updated:** [October 30, 2019, 2:06pm UTC](https://discourse.julialang.org/t/output-of-functions/30492 "2019-10-30T14:06:22Z")

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Dear users, I have the following function: function Test(u,v,w) x = sum(v) y = prod(v) z = u .+ v return (x,y,z) end But,if I want only the first, or only the second or only third output, how can I do…

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## [For syntax in @constraints](https://discourse.julialang.org/t/for-syntax-in-constraints/30483)

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**Author:** [@leclere](https://discourse.julialang.org/u/leclere)\
**Replies:** 1\
**Last updated:** [October 30, 2019, 1:28pm UTC](https://discourse.julialang.org/t/for-syntax-in-constraints/30483 "2019-10-30T13:28:48Z")

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Hi! I am looking for the most elegant way of adding multiple constraints (e.g. with a for loop) in a JuMP model. For example I would like to be able to write : using JuMP m = Model() @variable(m,x\[1:5\]) @constraints(…

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## [How do we know if a registeration attempt succeeded?](https://discourse.julialang.org/t/how-do-we-know-if-a-registeration-attempt-succeeded/30488)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 6\
**Last updated:** [October 30, 2019, 12:20pm UTC](https://discourse.julialang.org/t/how-do-we-know-if-a-registeration-attempt-succeeded/30488 "2019-10-30T12:20:10Z")

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If I $ git commit -am "@JuliaRegistrator register()" for one of my packages (namely COBS.jl), how do I know if my registration attempt succeeded? I understand that I’ll get an issue if things didn’t work, but is there su…

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## [Attempting to make my module code Threadsafe](https://discourse.julialang.org/t/attempting-to-make-my-module-code-threadsafe/30434)

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**Author:** [@StevenSiew](https://discourse.julialang.org/u/StevenSiew)\
**Replies:** 10\
**Last updated:** [October 30, 2019, 10:16am UTC](https://discourse.julialang.org/t/attempting-to-make-my-module-code-threadsafe/30434 "2019-10-30T10:16:27Z")

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I wrote my module PDFPs.jl to implement Precision Decimal Floating Point object. I was very very careful to make my code purely functional with pure functions. So I thought that my code is thread safe by default. But al…

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## [We can write an optimized BLAS library in pure Julia (please skip OP and jump to post 4)](https://discourse.julialang.org/t/we-can-write-an-optimized-blas-library-in-pure-julia-please-skip-op-and-jump-to-post-4/11634)

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**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 17\
**Last updated:** [October 30, 2019, 9:46am UTC](https://discourse.julialang.org/t/we-can-write-an-optimized-blas-library-in-pure-julia-please-skip-op-and-jump-to-post-4/11634 "2019-10-30T09:46:31Z")

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There’s a readme with a lot of output dumped on it here: https://github.com/chriselrod/TriangularMatrices.jl But the highlights are that, I found an fairly optimal “compute kernel” (at least for my architecture on Jul…

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## [Threading pool](https://discourse.julialang.org/t/threading-pool/30481)

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**Author:** [@fracasss](https://discourse.julialang.org/u/fracasss)\
**Replies:** 1\
**Last updated:** [October 30, 2019, 9:16am UTC](https://discourse.julialang.org/t/threading-pool/30481 "2019-10-30T09:16:37Z")

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How can I change the number of threads in my jl script, like the threading pool in Python? If there is no way to do this, can I set the number of threads Julia will use when Julia starts in VSCode? I really don’t want …

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## [The packages in different paths can't work together](https://discourse.julialang.org/t/the-packages-in-different-paths-cant-work-together/30472)

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**Author:** [@Yan](https://discourse.julialang.org/u/Yan)\
**Replies:** 4\
**Last updated:** [October 30, 2019, 8:38am UTC](https://discourse.julialang.org/t/the-packages-in-different-paths-cant-work-together/30472 "2019-10-30T08:38:21Z")

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The package “StringEncodings” installed in Repl, which only could be loaded in Repl but not in script by “using StringEncodings”

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## [What's a good way to get some value (doesn't matter what the value is) of a type \`T\` \`where T\`](https://discourse.julialang.org/t/whats-a-good-way-to-get-some-value-doesnt-matter-what-the-value-is-of-a-type-t-where-t/30474)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 11\
**Last updated:** [October 30, 2019, 7:55am UTC](https://discourse.julialang.org/t/whats-a-good-way-to-get-some-value-doesnt-matter-what-the-value-is-of-a-type-t-where-t/30474 "2019-10-30T07:55:56Z")

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I am writing some program that requires a value from a type T but it doesn’t matter what this type is. Is there a generic way to get some value of type T for whatever T? Happy to accept T for isbits.

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## [ApproxFun.jl Convolution/Fourier Multiplier](https://discourse.julialang.org/t/approxfun-jl-convolution-fourier-multiplier/30280)

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**Author:** [@cpross90](https://discourse.julialang.org/u/cpross90)\
**Replies:** 11\
**Last updated:** [October 30, 2019, 7:20am UTC](https://discourse.julialang.org/t/approxfun-jl-convolution-fourier-multiplier/30280 "2019-10-30T07:20:16Z")

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I’m trying to implement a solver for the Benjamin-Ono equation using DifferentialEquations.jl. I have periodic boundary conditions, so I’m using ApproxFun.jl to take the Fourier transform and use the method of lines to s…

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## [Best way to dispatch on whether a value is \`isbits\`?](https://discourse.julialang.org/t/best-way-to-dispatch-on-whether-a-value-is-isbits/30477)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [October 30, 2019, 7:10am UTC](https://discourse.julialang.org/t/best-way-to-dispatch-on-whether-a-value-is-isbits/30477 "2019-10-30T07:10:12Z")

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There are infinitely many types for which isbits is true. But I want to make my function dispatch on whether the eltype is isbits. What’s the best way to do that? I think of 4 approaches to do that 1.Use if Don’t use d…

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## [Numerical Jacobian](https://discourse.julialang.org/t/numerical-jacobian/30455)

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**Author:** [@jmcastro2109](https://discourse.julialang.org/u/jmcastro2109)\
**Replies:** 6\
**Last updated:** [October 30, 2019, 6:39am UTC](https://discourse.julialang.org/t/numerical-jacobian/30455 "2019-10-30T06:39:44Z")

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Hello! I am looking for the best package to compute a numerical Jacobian. Best, Juan

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## [How to read blocks or sections one by one from a txt file?](https://discourse.julialang.org/t/how-to-read-blocks-or-sections-one-by-one-from-a-txt-file/30469)

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**Author:** [@Yan](https://discourse.julialang.org/u/Yan)\
**Replies:** 3\
**Last updated:** [October 30, 2019, 3:57am UTC](https://discourse.julialang.org/t/how-to-read-blocks-or-sections-one-by-one-from-a-txt-file/30469 "2019-10-30T03:57:20Z")

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Is there a read block function besides readline and readlines, or more powerful function of them according a separate symbol. Such as: readline(“\*.txt”, separate=“\>”) # Change the default=“\\n” into “\>”

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## [Leading Zeros](https://discourse.julialang.org/t/leading-zeros/30450)

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**Author:** [@AlexanderChen](https://discourse.julialang.org/u/AlexanderChen)\
**Replies:** 10\
**Last updated:** [October 30, 2019, 3:20am UTC](https://discourse.julialang.org/t/leading-zeros/30450 "2019-10-30T03:20:03Z")

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Hi, I have a simple question but i cannot find the answer. I have an array of integers between 1 to 999. I need the left pading of 3 so that every element is composed of 3 digits.E.g. \[ 001, 002,…090…, 900\]. But I woul…

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## [Google Code-In](https://discourse.julialang.org/t/google-code-in/30460)

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**Author:** [@Naba7](https://discourse.julialang.org/u/Naba7)\
**Replies:** 2\
**Last updated:** [October 30, 2019, 1:51am UTC](https://discourse.julialang.org/t/google-code-in/30460 "2019-10-30T01:51:28Z")

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Hi all. This is Nabanita Dash, 3rd year B.Tech in IIIT, Bhubaneswar. I have been using Julia since last 6 months. I want to be a mentor for Google Code-in for Julia. How can I apply and prepare to deliver the best? I am …

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## [Newbie Question: Julia optimization multiprocessing](https://discourse.julialang.org/t/newbie-question-julia-optimization-multiprocessing/1686)

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**Author:** [@Jason](https://discourse.julialang.org/u/Jason)\
**Replies:** 10\
**Last updated:** [October 30, 2019, 1:12am UTC](https://discourse.julialang.org/t/newbie-question-julia-optimization-multiprocessing/1686 "2019-10-30T01:12:17Z")

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Hi, I’m trying to figure out whether Julia is a good language for a project I’m undertaking. One thing I’ll need to do is optimize a complex statistical function (Hidden Markov / CRF related) involving potentially 12K p…

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## [Packages on JupyterNotebook Supercloud](https://discourse.julialang.org/t/packages-on-jupyternotebook-supercloud/30459)

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**Author:** [@yejinyou](https://discourse.julialang.org/u/yejinyou)\
**Replies:** 1\
**Last updated:** [October 30, 2019, 1:11am UTC](https://discourse.julialang.org/t/packages-on-jupyternotebook-supercloud/30459 "2019-10-30T01:11:53Z")

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Hi. I have some troubles installing packages on Jupyter Notebook supercloud. Packages like Flux, Plots work with : import Pkg; Pkg.add("Flux") However, packages from git clones fail to clone. Examples are DiffEqFlux…

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## [Check package version](https://discourse.julialang.org/t/check-package-version/30155)

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**Author:** [@jheinen](https://discourse.julialang.org/u/jheinen)\
**Replies:** 1\
**Last updated:** [October 30, 2019, 12:09am UTC](https://discourse.julialang.org/t/check-package-version/30155 "2019-10-30T00:09:40Z")

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How can I test, whether a package is on #master? Pkg.API.installed()\[name\] no longer contains a ‘+’ to indicate this. Pkg.API.status(name) only displays (prints) the version information, but doesn’t return anything.

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## [3D variable in JuMP](https://discourse.julialang.org/t/3d-variable-in-jump/30416)

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**Author:** [@g001234](https://discourse.julialang.org/u/g001234)\
**Replies:** 4\
**Last updated:** [October 29, 2019, 11:45pm UTC](https://discourse.julialang.org/t/3d-variable-in-jump/30416 "2019-10-29T23:45:04Z")

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I am working on a convex optimization problem that needs to define several (e.g. 5) symmetric matrices as variables. I was wondering if it is possible to define those variables with a single line like @variable(m, x(N,N,…

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## [Save the date: 4th annual JuMP-dev](https://discourse.julialang.org/t/save-the-date-4th-annual-jump-dev/30465)

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**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 0\
**Last updated:** [October 29, 2019, 10:20pm UTC](https://discourse.julialang.org/t/save-the-date-4th-annual-jump-dev/30465 "2019-10-29T22:20:37Z")

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Dear all, We are pleased to announce that the 4th annual JuMP-dev workshop will be held June 15-17 2020 in Louvain-la-Neuve, Belgium, in conjunction with UCLouvain. Further details, including a call for speakers, will …

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## [CuArrays error: Unknown package Compat found in the compatibility requirements of MacroTools](https://discourse.julialang.org/t/cuarrays-error-unknown-package-compat-found-in-the-compatibility-requirements-of-macrotools/30464)

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**Author:** [@jchen975](https://discourse.julialang.org/u/jchen975)\
**Replies:** 0\
**Last updated:** [October 29, 2019, 10:13pm UTC](https://discourse.julialang.org/t/cuarrays-error-unknown-package-compat-found-in-the-compatibility-requirements-of-macrotools/30464 "2019-10-29T22:13:34Z")

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Hi, I’m trying to train a CNN on a compute cluster with a Nvidia V100 GPU. I ran a test .jl file (with Julia 1.1.1) that just does Pkg.test("CuArrays") and this is the error message I got ERROR: LoadError: Unknown packa…

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## [Julia 1.4 feature freeze: Dec 15th](https://discourse.julialang.org/t/julia-1-4-feature-freeze-dec-15th/30453)

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**Author:** [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Replies:** 1\
**Last updated:** [October 29, 2019, 7:23pm UTC](https://discourse.julialang.org/t/julia-1-4-feature-freeze-dec-15th/30453 "2019-10-29T19:23:07Z")

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Heads up: this is to let people know that if they have any PRs that they really want to get into Julia 1.4, the feature freeze for the 1.4 release will be on Sunday, December 15th. If you want something to be in this rel…

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## [Synchronous requests needs to be performed one at a time on remote worker](https://discourse.julialang.org/t/synchronous-requests-needs-to-be-performed-one-at-a-time-on-remote-worker/30140)

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**Author:** [@cwiese](https://discourse.julialang.org/u/cwiese)\
**Replies:** 3\
**Last updated:** [October 29, 2019, 7:21pm UTC](https://discourse.julialang.org/t/synchronous-requests-needs-to-be-performed-one-at-a-time-on-remote-worker/30140 "2019-10-29T19:21:57Z")

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We want to prevent race conditions on remote workers serving requests from HTTP.jl on porocess 1. We are trying to stack the “requests” in a channel… trying to figure out how to do this with remotecall\_fetch and Channe…

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## [Getting error while using CurricularAnalytics](https://discourse.julialang.org/t/getting-error-while-using-curricularanalytics/30389)

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**Author:** [@Gaurav\_Sharma](https://discourse.julialang.org/u/Gaurav_Sharma)\
**Replies:** 2\
**Last updated:** [October 29, 2019, 6:55pm UTC](https://discourse.julialang.org/t/getting-error-while-using-curricularanalytics/30389 "2019-10-29T18:55:43Z")

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Version of Julia: “1.3.0-rc4.1” CurricularAnalytics v0.6.0 “”" import Pkg Pkg.add(“CurricularAnalytics”) using CurricularAnalytics Info: Precompiling CurricularAnalytics \[593ffa3d-269e-5d81-88bc-c3b6809c35a6\] └ @ …

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## [Plot, pyplot() - marker size inside the legend](https://discourse.julialang.org/t/plot-pyplot-marker-size-inside-the-legend/30454)

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**Author:** [@juliauser](https://discourse.julialang.org/u/juliauser)\
**Replies:** 0\
**Last updated:** [October 29, 2019, 5:52pm UTC](https://discourse.julialang.org/t/plot-pyplot-marker-size-inside-the-legend/30454 "2019-10-29T17:52:16Z")

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Hi, I can change the legendfont but the market size inside the legend doesn’t change accordingly. How can I change it? Thanks

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## [DifferentialEquations: Change parameter in ODE after some time](https://discourse.julialang.org/t/differentialequations-change-parameter-in-ode-after-some-time/30438)

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**Author:** [@rad1um](https://discourse.julialang.org/u/rad1um)\
**Replies:** 3\
**Last updated:** [October 29, 2019, 5:24pm UTC](https://discourse.julialang.org/t/differentialequations-change-parameter-in-ode-after-some-time/30438 "2019-10-29T17:24:38Z")

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Hello everyone, I hope that this question belongs here, since my problem is mostly about the DifferentialEquations package. I have the following dynamical system: using DifferentialEquations function some\_dynamics(u,p…

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## [DifferentialEquations: Enforce that variables are inside a domain (isoutofdomain, PositiveDomain)](https://discourse.julialang.org/t/differentialequations-enforce-that-variables-are-inside-a-domain-isoutofdomain-positivedomain/30452)

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**Author:** [@LolianSh](https://discourse.julialang.org/u/LolianSh)\
**Replies:** 1\
**Last updated:** [October 29, 2019, 4:20pm UTC](https://discourse.julialang.org/t/differentialequations-enforce-that-variables-are-inside-a-domain-isoutofdomain-positivedomain/30452 "2019-10-29T16:20:43Z")

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Hi, I am using DifferentialEquations.jl to solve a system of SDEs. This is a model of an electrochemical system, where I have reaction-diffusion equations. My variables are the following (\\theta, CO, OH, S\_t). All of t…

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## [Is there a /dev/null for AbstractArrays?](https://discourse.julialang.org/t/is-there-a-dev-null-for-abstractarrays/30447)

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**Author:** [@HenrikM](https://discourse.julialang.org/u/HenrikM)\
**Replies:** 9\
**Last updated:** [October 29, 2019, 4:18pm UTC](https://discourse.julialang.org/t/is-there-a-dev-null-for-abstractarrays/30447 "2019-10-29T16:18:01Z")

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Is there some type that I can pass into functions that would indicate that I don’t care about the result? The background is that I always try to write in place functions. When I have a, b, c = f(x, y, z) I always implem…

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## [The Atom in juliapro is crashed while opening package manager](https://discourse.julialang.org/t/the-atom-in-juliapro-is-crashed-while-opening-package-manager/30387)

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**Author:** [@Yan](https://discourse.julialang.org/u/Yan)\
**Replies:** 5\
**Last updated:** [October 29, 2019, 3:20pm UTC](https://discourse.julialang.org/t/the-atom-in-juliapro-is-crashed-while-opening-package-manager/30387 "2019-10-29T15:20:22Z")

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## [Problem with the positivedefinitivenesse of a kernel matrix](https://discourse.julialang.org/t/problem-with-the-positivedefinitivenesse-of-a-kernel-matrix/28976)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 8\
**Last updated:** [October 29, 2019, 2:37pm UTC](https://discourse.julialang.org/t/problem-with-the-positivedefinitivenesse-of-a-kernel-matrix/28976 "2019-10-29T14:37:51Z")

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Hi guys, I am trying to generate a positive definite kernel matrix. Below is the minimalistic code: julia\> using MultivariateStats, ForwardDiff, StatsBase, MLKernels, LinearAlgebra, Optim, Plots, Distributions, Forwar…

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## [PhD scholarship in dynamical systems/nonlinear dynamics](https://discourse.julialang.org/t/phd-scholarship-in-dynamical-systems-nonlinear-dynamics/28462)

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**Author:** [@dawbarton](https://discourse.julialang.org/u/dawbarton)\
**Replies:** 0\
**Last updated:** [September 6, 2019, 11:36am UTC](https://discourse.julialang.org/t/phd-scholarship-in-dynamical-systems-nonlinear-dynamics/28462 "2019-09-06T11:36:03Z")

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A bit of a long shot, but if there is anyone who is looking to do a PhD in dynamical systems/nonlinear dynamics, would like to develop Julia-based dynamics software, and is based in the UK, I’d love to hear from you. I’m…

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