# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1607

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

**Page:** 1608

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## [Adding a 3d curve to a 3d surface plot breaks the surface colourmap](https://discourse.julialang.org/t/adding-a-3d-curve-to-a-3d-surface-plot-breaks-the-surface-colourmap/48059)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 1\
**Last updated:** [October 9, 2020, 6:55pm UTC](https://discourse.julialang.org/t/adding-a-3d-curve-to-a-3d-surface-plot-breaks-the-surface-colourmap/48059 "2020-10-09T18:55:58Z")

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I am trying to add a 3d curve to a 3d surface plot. Without the curve, the surface plot functions as expected: it has different colours for different values along the z axis. However, if I try to add a 3d curve, the co…

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## [New user Welcome Post](https://discourse.julialang.org/t/new-user-welcome-post/48057)

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**Author:** [@vaeli](https://discourse.julialang.org/u/vaeli)\
**Replies:** 0\
**Last updated:** [October 9, 2020, 5:49pm UTC](https://discourse.julialang.org/t/new-user-welcome-post/48057 "2020-10-09T17:49:13Z")

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Hello! First I suggest that Infobot should, in first greeting, tell, where the new user introductions go. Whether they have a question, introduce themselves or ask a typical “what should I use”. I was looking around to …

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## [No method matching \`oneunit(::Type{Any})\` when solving matrix equation](https://discourse.julialang.org/t/no-method-matching-oneunit-type-any-when-solving-matrix-equation/48020)

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**Author:** [@kapple](https://discourse.julialang.org/u/kapple)\
**Replies:** 19\
**Last updated:** [October 9, 2020, 2:32pm UTC](https://discourse.julialang.org/t/no-method-matching-oneunit-type-any-when-solving-matrix-equation/48020 "2020-10-09T14:32:57Z")

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I have some functions trying to solve a matrix equation u = A\\b inside a function. Upon running the function, I receive the error ERROR: MethodError: no method matching oneunit(::Type{Any}) What’s strange is, I copy …

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## [Pair of non-intersecting shortest paths on undirected graph](https://discourse.julialang.org/t/pair-of-non-intersecting-shortest-paths-on-undirected-graph/47988)

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**Author:** [@mastrof](https://discourse.julialang.org/u/mastrof)\
**Replies:** 6\
**Last updated:** [October 9, 2020, 5:30pm UTC](https://discourse.julialang.org/t/pair-of-non-intersecting-shortest-paths-on-undirected-graph/47988 "2020-10-09T17:30:24Z")

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Hello, I only have a very basic background in graph theory and don’t really know the ideas behind most of the algorithms that are used for path/cycle detection, yet I have somehow found myself in a position where I’m wo…

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## [Julia Meetup in Rio de Janeiro - Oct 10, 2019](https://discourse.julialang.org/t/julia-meetup-in-rio-de-janeiro-oct-10-2019/28748)

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**Author:** [@felipenoris](https://discourse.julialang.org/u/felipenoris)\
**Replies:** 3\
**Last updated:** [October 9, 2020, 5:05pm UTC](https://discourse.julialang.org/t/julia-meetup-in-rio-de-janeiro-oct-10-2019/28748 "2020-10-09T17:05:46Z")

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https://jugrio.github.io/

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## [Initialization of array of arrays with \`fill(ones(1),2,2)\`: only one vector is created](https://discourse.julialang.org/t/initialization-of-array-of-arrays-with-fill-ones-1-2-2-only-one-vector-is-created/48048)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 3\
**Last updated:** [October 9, 2020, 4:24pm UTC](https://discourse.julialang.org/t/initialization-of-array-of-arrays-with-fill-ones-1-2-2-only-one-vector-is-created/48048 "2020-10-09T16:24:58Z")

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Disclaimer: this is explicit in the help entry of fill, so I am not complaining of anything… julia\> m = fill(ones(1),2,2) 2×2 Array{Array{Float64,1},2}: \[1.0\] \[1.0\] \[1.0\] \[1.0\] julia\> m\[1,1\]\[1\] = 2 2 julia\> m 2×2 …

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## [Getting strange MV Normal samples based on sparse precision matrix](https://discourse.julialang.org/t/getting-strange-mv-normal-samples-based-on-sparse-precision-matrix/48001)

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**Author:** [@ElOceanografo](https://discourse.julialang.org/u/ElOceanografo)\
**Replies:** 5\
**Last updated:** [October 9, 2020, 4:02pm UTC](https://discourse.julialang.org/t/getting-strange-mv-normal-samples-based-on-sparse-precision-matrix/48001 "2020-10-09T16:02:37Z")

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I’ve noticed something odd while trying to generate Gaussian Markov random fields on an irregular mesh. In this model, a spatial field is a multivariate normal variable defined on the mesh nodes. The distribution is de…

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## [\[ANN\] Websocket - High level API for Server and Client with documentation](https://discourse.julialang.org/t/ann-websocket-high-level-api-for-server-and-client-with-documentation/47957)

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**Author:** [@citkane](https://discourse.julialang.org/u/citkane)\
**Replies:** 4\
**Last updated:** [October 9, 2020, 2:56pm UTC](https://discourse.julialang.org/t/ann-websocket-high-level-api-for-server-and-client-with-documentation/47957 "2020-10-09T14:56:54Z")

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Websocket.jl Github Code Why another Websocket package? The existing Julia websocket solutions are in various states of development and lack comprehensive high level API’s comparable to offerings in other languages s…

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## [Error when opening notebook files](https://discourse.julialang.org/t/error-when-opening-notebook-files/48038)

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**Author:** [@Carfo](https://discourse.julialang.org/u/Carfo)\
**Replies:** 2\
**Last updated:** [October 9, 2020, 2:10pm UTC](https://discourse.julialang.org/t/error-when-opening-notebook-files/48038 "2020-10-09T14:10:24Z")

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I followed the instructions, tried it on two different computers but each time I open a notebook file I receive the below error (any ideas as to how I can fix this?): Fetch content failed syntaxerror: unexpected token \<…

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## [JuMP Container Benchmark](https://discourse.julialang.org/t/jump-container-benchmark/47844)

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**Author:** [@SonntagK](https://discourse.julialang.org/u/SonntagK)\
**Replies:** 3\
**Last updated:** [October 9, 2020, 1:41pm UTC](https://discourse.julialang.org/t/jump-container-benchmark/47844 "2020-10-09T13:41:29Z")

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Hello, we are Julia beginners. We want to use Julia for solving linear programs using JuMP and some external solver. For very large LP problems the model generation time can be significant. Since JuMP covers many differ…

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## [How to wait on a condition for tasks](https://discourse.julialang.org/t/how-to-wait-on-a-condition-for-tasks/48023)

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**Author:** [@prototact](https://discourse.julialang.org/u/prototact)\
**Replies:** 10\
**Last updated:** [October 9, 2020, 12:33pm UTC](https://discourse.julialang.org/t/how-to-wait-on-a-condition-for-tasks/48023 "2020-10-09T12:33:02Z")

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I am having some practice with tasks, channels and conditions. I would like to wait on a specific condition with a timeout. If the timeout ends, just put! a default value and continue, otherwise put! a specific value in…

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## [Defining binary operators inner product angle brackets](https://discourse.julialang.org/t/defining-binary-operators-inner-product-angle-brackets/48025)

<div class="topic-metadata">

**Author:** [@kapple](https://discourse.julialang.org/u/kapple)\
**Replies:** 1\
**Last updated:** [October 9, 2020, 11:37am UTC](https://discourse.julialang.org/t/defining-binary-operators-inner-product-angle-brackets/48025 "2020-10-09T11:37:31Z")

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I’d like to define an inner product, and I’m wondering if it’s possible to call it using the angle brackets. using QuadGK # "Definition" (quote-unquote) ⟨u, v⟩ = quadgk(x -\> u(x)\*v(x), 0, 1, rtol = 1e-3) # Usage u(x) …

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## [Using: include("file.jl") | Variables](https://discourse.julialang.org/t/using-include-file-jl-variables/48017)

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**Author:** [@Jea](https://discourse.julialang.org/u/Jea)\
**Replies:** 2\
**Last updated:** [October 9, 2020, 7:31am UTC](https://discourse.julialang.org/t/using-include-file-jl-variables/48017 "2020-10-09T07:31:18Z")

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How could the hi variable of second.jl be used in first.jl knowing that an include is made in second.jl over first.jl Example first.jl any = "$(hi)" # hi is undefined println() second.jl hi = "hola" # variable for u…

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## [Remote plotting using ssh and visual studio code](https://discourse.julialang.org/t/remote-plotting-using-ssh-and-visual-studio-code/48015)

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**Author:** [@Dale\_James\_Black](https://discourse.julialang.org/u/Dale_James_Black)\
**Replies:** 2\
**Last updated:** [October 9, 2020, 6:28am UTC](https://discourse.julialang.org/t/remote-plotting-using-ssh-and-visual-studio-code/48015 "2020-10-09T06:28:20Z")

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I am on a MacBook Pro and I am using visual studio code to ssh into my university cluster. I have XQuartz downloaded onto my MacBook and when I open up a basic terminal and remote into my cluster I can run commands like x…

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## [Why is it slower when you declare an array like this?](https://discourse.julialang.org/t/why-is-it-slower-when-you-declare-an-array-like-this/47962)

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**Author:** [@anon60034542](https://discourse.julialang.org/u/anon60034542)\
**Replies:** 15\
**Last updated:** [October 9, 2020, 2:51am UTC](https://discourse.julialang.org/t/why-is-it-slower-when-you-declare-an-array-like-this/47962 "2020-10-09T02:51:07Z")

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I’ve read that when I declare an array like this: a = \[1,2,3,4,5\] it can be slower, but why? Is it because Julia has to determine the type? Can it be slower when you don’t provide the dimensions of an array? For examp…

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## [Base.div vs Html.div - specialize or not?](https://discourse.julialang.org/t/base-div-vs-html-div-specialize-or-not/47776)

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**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 29\
**Last updated:** [October 9, 2020, 12:25am UTC](https://discourse.julialang.org/t/base-div-vs-html-div-specialize-or-not/47776 "2020-10-09T00:25:10Z")

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Dear Julians, I have a major dilemma. I’ve been going back and forth between how to handle this and I was wondering if there’s any best practice? There is a Html.div function which creates a HTML \<div\>...\</div\> element.…

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## [Developing annotation standards for sciml to support reproduceability of published work](https://discourse.julialang.org/t/developing-annotation-standards-for-sciml-to-support-reproduceability-of-published-work/47992)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 2\
**Last updated:** [October 8, 2020, 11:12pm UTC](https://discourse.julialang.org/t/developing-annotation-standards-for-sciml-to-support-reproduceability-of-published-work/47992 "2020-10-08T23:12:02Z")

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Does a project like this already exist outside of julia? It seems that the current level of integration among julia packages for machine-learning, mechanistic modeling, and data provides a unique opportunity to develop …

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## [Documentation of Clp.jl](https://discourse.julialang.org/t/documentation-of-clp-jl/48005)

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**Author:** [@JohnZ](https://discourse.julialang.org/u/JohnZ)\
**Replies:** 1\
**Last updated:** [October 8, 2020, 11:06pm UTC](https://discourse.julialang.org/t/documentation-of-clp-jl/48005 "2020-10-08T23:06:28Z")

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The documentation of the Julia wapper to the Clp solver is a bit out of date. Under options, “SolveType” is still listed but it looks like it has been replaced by “Algorithm”: https://github.com/jump-dev/Clp.jl Options …

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## [Domain representation](https://discourse.julialang.org/t/domain-representation/47965)

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**Author:** [@Azzaare](https://discourse.julialang.org/u/Azzaare)\
**Replies:** 2\
**Last updated:** [October 8, 2020, 10:53pm UTC](https://discourse.julialang.org/t/domain-representation/47965 "2020-10-08T22:53:26Z")

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Hi there! EDIT: I am trying to provide a type/structure overview, so please be patient if you want/need more details about my question I am writing a solver where I have to represent the domain of each variable. I was …

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## [Using Z3.jl](https://discourse.julialang.org/t/using-z3-jl/48006)

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**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 1\
**Last updated:** [October 8, 2020, 10:25pm UTC](https://discourse.julialang.org/t/using-z3-jl/48006 "2020-10-08T22:25:13Z")

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I am trying to use atleast and atmost to set up constraints but not sure how these work (type of the first argument). The method signature is # 1 method for generic function "atleast": \[1\] atleast(arg1::Union{CxxWrap.…

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## [Generic code for elementwise minimum](https://discourse.julialang.org/t/generic-code-for-elementwise-minimum/22921)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 8\
**Last updated:** [October 8, 2020, 10:14pm UTC](https://discourse.julialang.org/t/generic-code-for-elementwise-minimum/22921 "2020-10-08T22:14:31Z")

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I am wondering how to program a generic elementwise minimum of, say, vectors, with the following in mind: the result from an AbstractVector{T} is a T, eg SVector and Vector would be preserved. Data-generating MWE: usin…

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## [Problem with optional argument with default value of missing](https://discourse.julialang.org/t/problem-with-optional-argument-with-default-value-of-missing/48002)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 2\
**Last updated:** [October 8, 2020, 9:25pm UTC](https://discourse.julialang.org/t/problem-with-optional-argument-with-default-value-of-missing/48002 "2020-10-08T21:25:29Z")

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I have a small package CurrentPopulationSurvey.jl that I’m working on and in it I have the following function defined: function cpsdata(year::Int, month::Int, vars::Vector{String}=missing) data = readdlm(project\_pat…

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## [Build.jl from command line vs. from Pkg.build()](https://discourse.julialang.org/t/build-jl-from-command-line-vs-from-pkg-build/48003)

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**Author:** [@Graham\_Gill](https://discourse.julialang.org/u/Graham_Gill)\
**Replies:** 0\
**Last updated:** [October 8, 2020, 8:59pm UTC](https://discourse.julialang.org/t/build-jl-from-command-line-vs-from-pkg-build/48003 "2020-10-08T20:59:19Z")

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In test/runtests.jl I have using Test using Logging using MyPackage #... but in test/Project.toml, MyPackage is not a dependency. I understand that when I’m in the main project folder and Pkg.activate("."), then Pkg.te…

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## [Determine the scope of symbols in an Expr](https://discourse.julialang.org/t/determine-the-scope-of-symbols-in-an-expr/47993)

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**Author:** [@Mason](https://discourse.julialang.org/u/Mason)\
**Replies:** 1\
**Last updated:** [October 8, 2020, 5:17pm UTC](https://discourse.julialang.org/t/determine-the-scope-of-symbols-in-an-expr/47993 "2020-10-08T17:17:48Z")

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I asked about this on Zulip and cleaned it up and posted to Stack Overflow but I figure it might be helpful to cross pollinate here as well. I know I’ve wondered how to do this a few times, so probably other people have …

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## [OpenBLAS + Flux bottleknecks?](https://discourse.julialang.org/t/openblas-flux-bottleknecks/47995)

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**Author:** [@kc104](https://discourse.julialang.org/u/kc104)\
**Replies:** 4\
**Last updated:** [October 8, 2020, 8:10pm UTC](https://discourse.julialang.org/t/openblas-flux-bottleknecks/47995 "2020-10-08T20:10:53Z")

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I’ve been reimplementing some of my PyTorch code in julia as a way to learn the language and I came across some behaviour I don’t understand when using Flux for doing gradient based optimization on a CPU. In this practic…

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## [Pkg: 60s lag](https://discourse.julialang.org/t/pkg-60s-lag/47998)

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**Author:** [@Peter\_Adelman](https://discourse.julialang.org/u/Peter_Adelman)\
**Replies:** 5\
**Last updated:** [October 8, 2020, 7:54pm UTC](https://discourse.julialang.org/t/pkg-60s-lag/47998 "2020-10-08T19:54:06Z")

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I will preface this post by saying that I doubt this could have anything to do with Pkg.jl or julialang.org. However, this is what I observe (numbers are seconds since start of build stage): So it pulls 8 items and …

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## [Workfow for data analysis project: avoid re-running with many inputs, intermediate steps, and models](https://discourse.julialang.org/t/workfow-for-data-analysis-project-avoid-re-running-with-many-inputs-intermediate-steps-and-models/47997)

<div class="topic-metadata">

**Author:** [@jdossgollin](https://discourse.julialang.org/u/jdossgollin)\
**Replies:** 8\
**Last updated:** [October 8, 2020, 7:21pm UTC](https://discourse.julialang.org/t/workfow-for-data-analysis-project-avoid-re-running-with-many-inputs-intermediate-steps-and-models/47997 "2020-10-08T19:21:56Z")

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A typical data analysis project, for me, has many steps. For example, I might read in some datasets, fit some probabilistic models, create a database of simulations from this posterior model, and optimize something over …

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## [ANN: Data parallelism tutorial](https://discourse.julialang.org/t/ann-data-parallelism-tutorial/47824)

<div class="topic-metadata">

**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 8\
**Last updated:** [October 8, 2020, 6:33pm UTC](https://discourse.julialang.org/t/ann-data-parallelism-tutorial/47824 "2020-10-08T18:33:44Z")

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Hi, I just wrote A quick introduction to data parallelism in Julia! For a quick flavor of the tutorial, here is the table of contents: Getting julia and libraries Starting julia Starting julia with multiple worker p…

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## [Parallelism - Understanding pmap and the batch\_size parameter](https://discourse.julialang.org/t/parallelism-understanding-pmap-and-the-batch-size-parameter/15604)

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**Author:** [@mdsalerno](https://discourse.julialang.org/u/mdsalerno)\
**Replies:** 1\
**Last updated:** [October 8, 2020, 3:22pm UTC](https://discourse.julialang.org/t/parallelism-understanding-pmap-and-the-batch-size-parameter/15604 "2020-10-08T15:22:12Z")

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I am running something that looks like the following: addprocs(Sys.CPU\_THREADS) pmap(x -\> f(x, A, B, C), args) I have 48 CPU cores and thus 48 workers after running addprocs. A, B, and C are DataFrames, the largest h…

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## [ERROR: type DataType has no field optimizer\_constructor](https://discourse.julialang.org/t/error-type-datatype-has-no-field-optimizer-constructor/47920)

<div class="topic-metadata">

**Author:** [@umbe](https://discourse.julialang.org/u/umbe)\
**Replies:** 3\
**Last updated:** [October 8, 2020, 2:54pm UTC](https://discourse.julialang.org/t/error-type-datatype-has-no-field-optimizer-constructor/47920 "2020-10-08T14:54:40Z")

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Hi everyone, I’m having a problem with JuMP/Juniper. For first I create an optimization model m = Model(Juniper.Optimizer) set\_optimizer\_attribute(m, "nl\_solver", Ipopt.Optimizer) set\_optimizer\_attribute(m…

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