# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1435

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

**Page:** 1436

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## [Economist's doing dynamic programming and structural estimation](https://discourse.julialang.org/t/economists-doing-dynamic-programming-and-structural-estimation/58171)

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**Author:** [@jovansam](https://discourse.julialang.org/u/jovansam)\
**Replies:** 12\
**Last updated:** [April 6, 2021, 1:42am UTC](https://discourse.julialang.org/t/economists-doing-dynamic-programming-and-structural-estimation/58171 "2021-04-06T01:42:33Z")

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I love discourse because you get to learn from experts across fields. This is really nice!. At the same time, I would like to learn from people with closely aligned work as mine. Thus, I was wondering whether some econo…

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## [Fast 4D argmax](https://discourse.julialang.org/t/fast-4d-argmax/58566)

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**Author:** [@jroon](https://discourse.julialang.org/u/jroon)\
**Replies:** 26\
**Last updated:** [April 6, 2021, 1:06am UTC](https://discourse.julialang.org/t/fast-4d-argmax/58566 "2021-04-06T01:06:04Z")

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Hi Julia-folks! I’m new to Julia (very new), but work mainly in R. I’m trying to replace a slow bit of R code with a Julia function that I will call from within R. Essentially what I’m trying to achieve is argmax of a 4…

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## [Julia slows down after computer upgrade](https://discourse.julialang.org/t/julia-slows-down-after-computer-upgrade/58503)

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**Author:** [@mengxiaoliu](https://discourse.julialang.org/u/mengxiaoliu)\
**Replies:** 15\
**Last updated:** [April 6, 2021, 12:46am UTC](https://discourse.julialang.org/t/julia-slows-down-after-computer-upgrade/58503 "2021-04-06T00:46:19Z")

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Hi. I am very new to Julia and am not a computer geek so this question may not be very clear. I am happy to add any information as necessary. I am running Julia on VSCode in Windows. I recently added some memory sticks …

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## [Ternary diagrams and surfaces on non-rectangular grids](https://discourse.julialang.org/t/ternary-diagrams-and-surfaces-on-non-rectangular-grids/43423)

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**Author:** [@SEA](https://discourse.julialang.org/u/SEA)\
**Replies:** 12\
**Last updated:** [April 6, 2021, 12:46am UTC](https://discourse.julialang.org/t/ternary-diagrams-and-surfaces-on-non-rectangular-grids/43423 "2021-04-06T00:46:05Z")

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I would like to plot a surface on a triangular domain. Is there a Julia project which can plot ternary diagrams, akin to this code?

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## [Lazy constraint callback issue with GLPK](https://discourse.julialang.org/t/lazy-constraint-callback-issue-with-glpk/58345)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 5\
**Last updated:** [April 5, 2021, 11:28pm UTC](https://discourse.julialang.org/t/lazy-constraint-callback-issue-with-glpk/58345 "2021-04-05T23:28:07Z")

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Hi , The callback is not working in GLPK. The below code is working in fine Gurobi. using JuMP, Gurobi,MathOptInterface,GLPK model = Model(Gurobi.Optimizer) set\_optimizer\_attribute(model, "OutputFlag", 0) …

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## [Finite Element Assembly using map over elements](https://discourse.julialang.org/t/finite-element-assembly-using-map-over-elements/58576)

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**Author:** [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Replies:** 6\
**Last updated:** [April 5, 2021, 9:24am UTC](https://discourse.julialang.org/t/finite-element-assembly-using-map-over-elements/58576 "2021-04-05T09:24:19Z")

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Hi, I am wondering whether the loop over the elements in a finite element assembly can be replace by a flavor of map over the list of elements. I am happy to consider the linear elements on a one-dimensional mesh to st…

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## [Creating Animation from multiple Images](https://discourse.julialang.org/t/creating-animation-from-multiple-images/58559)

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**Author:** [@tgautam03](https://discourse.julialang.org/u/tgautam03)\
**Replies:** 9\
**Last updated:** [April 5, 2021, 9:15pm UTC](https://discourse.julialang.org/t/creating-animation-from-multiple-images/58559 "2021-04-05T21:15:12Z")

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Hi, I’m working on a project where I’ve to work with reflecting rays. I’ve written the code to trace the rays and reflection, but want to visualize the ray paths (just to quickly make sure that everything works well). I …

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## [Design preconditioner for unconstrained optimization problem](https://discourse.julialang.org/t/design-preconditioner-for-unconstrained-optimization-problem/58650)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 10:35pm UTC](https://discourse.julialang.org/t/design-preconditioner-for-unconstrained-optimization-problem/58650 "2021-04-05T22:35:33Z")

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Hello, I am working on the greedy algorithm developed in Baptista et al. (https://arxiv.org/pdf/2009.10303.pdf) to approximate the components of a transport map S (aka normalizing flow) that pushes forward a target den…

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## [Obtaining Irreducible Inconsistent Subsystem (IIS) with JumP - Gurobi](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491)

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**Author:** [@priantop](https://discourse.julialang.org/u/priantop)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 9:27pm UTC](https://discourse.julialang.org/t/obtaining-irreducible-inconsistent-subsystem-iis-with-jump-gurobi/58491 "2021-04-05T21:27:11Z")

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Hi, I am kind of new to Julia (+/- 3 months of usage) I am trying to find which constraints are members of IIS of an Infeasible or Unbounded optimisation problem. For example, I have the following script using JuMP, G…

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## [How to avoid boxed function names in closures?](https://discourse.julialang.org/t/how-to-avoid-boxed-function-names-in-closures/58579)

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**Author:** [@matthias314](https://discourse.julialang.org/u/matthias314)\
**Replies:** 6\
**Last updated:** [April 5, 2021, 8:29pm UTC](https://discourse.julialang.org/t/how-to-avoid-boxed-function-names-in-closures/58579 "2021-04-05T20:29:18Z")

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Hello! In order to avoid performance problems, I would like to know whether boxes can be avoided in two kinds of closures. Without closures, all problems mentioned below disappear. I’m using Julia 1.6.0. Keyword argumen…

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## [Symbolics: ERROR: TypeError: non-boolean (Num) used in boolean context](https://discourse.julialang.org/t/symbolics-error-typeerror-non-boolean-num-used-in-boolean-context/58640)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 8:43pm UTC](https://discourse.julialang.org/t/symbolics-error-typeerror-non-boolean-num-used-in-boolean-context/58640 "2021-04-05T20:43:01Z")

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So what should one do if you want to evaluate a function symbolically and there may be things like boolean switches in it? Is there such a thing as switchable symbolic equations? I had some functions like that may inc…

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## [Interpolation problems](https://discourse.julialang.org/t/interpolation-problems/58631)

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**Author:** [@leopdsf](https://discourse.julialang.org/u/leopdsf)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 8:36pm UTC](https://discourse.julialang.org/t/interpolation-problems/58631 "2021-04-05T20:36:41Z")

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Hello there! I have a matrix S(N,2) with data and I want to interpolate S\[:,2\] as a function of S\[:,1\]. I wrote the following using DataInterpolations vm = S\[:,2\] vh = S\[:,1\] im = LinearInterpolation(vm,vh) It pres…

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## [We're looking for a private tutor proficient in Julia, AWS, and GCP](https://discourse.julialang.org/t/were-looking-for-a-private-tutor-proficient-in-julia-aws-and-gcp/58642)

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**Author:** [@andretaibei](https://discourse.julialang.org/u/andretaibei)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 8:11pm UTC](https://discourse.julialang.org/t/were-looking-for-a-private-tutor-proficient-in-julia-aws-and-gcp/58642 "2021-04-05T20:11:42Z")

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We’re looking for a private tutor proficient in Julia, AWS, and GCP (if interested, apply here) : Online Tutor Certified in Google Cloud+AWS Machine Learning - Remote - Indeed.com

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## [CAS benchmarks (Symbolics.jl and Maxima)](https://discourse.julialang.org/t/cas-benchmarks-symbolics-jl-and-maxima/58359)

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**Author:** [@rfateman](https://discourse.julialang.org/u/rfateman)\
**Replies:** 36\
**Last updated:** [April 5, 2021, 8:06pm UTC](https://discourse.julialang.org/t/cas-benchmarks-symbolics-jl-and-maxima/58359 "2021-04-05T20:06:29Z")

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I still don’t understand why you are touting the speed of Julia symbolic code (compiled) compared to the speed of SymPy (interpreted). I looked for a benchmark that could be run in (say) Maxima, but finally came up a r…

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## [@time and @btime show different allocations](https://discourse.julialang.org/t/time-and-btime-show-different-allocations/58632)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 7:15pm UTC](https://discourse.julialang.org/t/time-and-btime-show-different-allocations/58632 "2021-04-05T19:15:26Z")

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Hey Julianners, What can be the difference, that makes @time and @btime time different time in these scenarios? a, b = 6, 7 foo(a, b) = begin for i = 1:2 a, b=a + 6, b + 7+i end end @time foo(a,b) @time foo(a,b…

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## [\[ANN\] MPIMapReduce.jl: A simplified mapreduce using MPI](https://discourse.julialang.org/t/ann-mpimapreduce-jl-a-simplified-mapreduce-using-mpi/58635)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 6:35pm UTC](https://discourse.julialang.org/t/ann-mpimapreduce-jl-a-simplified-mapreduce-using-mpi/58635 "2021-04-05T18:35:39Z")

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MPI is the state-of-the-art in multiprocessing on HPC clusters, however the syntax of MPI may be a bit unfamiliar for beginners. MPI.jl provides Julia wrappers for MPI that make the process much simpler. This package pro…

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## [Solve for upper/lower bound of a numerical definite integral](https://discourse.julialang.org/t/solve-for-upper-lower-bound-of-a-numerical-definite-integral/58164)

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**Author:** [@carloslesmes](https://discourse.julialang.org/u/carloslesmes)\
**Replies:** 24\
**Last updated:** [April 5, 2021, 6:23pm UTC](https://discourse.julialang.org/t/solve-for-upper-lower-bound-of-a-numerical-definite-integral/58164 "2021-04-05T18:23:52Z")

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Hi, I’m trying to solve for b, given f, a and k, please help, Is there a way to do it in julia? quadgk(f,a,b)=k Thanks

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## [How to read a Jupyter notebook when kernel keeps dying](https://discourse.julialang.org/t/how-to-read-a-jupyter-notebook-when-kernel-keeps-dying/58626)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 5:41pm UTC](https://discourse.julialang.org/t/how-to-read-a-jupyter-notebook-when-kernel-keeps-dying/58626 "2021-04-05T17:41:58Z")

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I have changed to Julia 1.6.0. My Jupyter kernel is also 1.6.0. But when I try to open some (old) ipnyb file, my kernel dies. What shall I do? Shall I build an old (compatible) kernel? If yes, how can I do it?

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## [Pluto: hide md"" cell automatically?](https://discourse.julialang.org/t/pluto-hide-md-cell-automatically/58628)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 5:22pm UTC](https://discourse.julialang.org/t/pluto-hide-md-cell-automatically/58628 "2021-04-05T17:22:00Z")

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Is there a way to automatically hide the code when writing a markdown cell in Pluto? Either an alternative to Shift-Enter and/or Control-Enter that hides the code, or a global environment variable would fit. Usually mark…

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## [AST example in julia](https://discourse.julialang.org/t/ast-example-in-julia/58625)

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**Author:** [@csango](https://discourse.julialang.org/u/csango)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 4:05pm UTC](https://discourse.julialang.org/t/ast-example-in-julia/58625 "2021-04-05T16:05:54Z")

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Hi, I was trying to generate the AST for the following code snippet: function alma(c) f(x,y) = 3x + 4y A = Int8\[1, 2, 3\] \* c B = \[4.0, 5.0, 6.0\] .+ c return f(A,B)/c end str = open(f-\>read(f, String), …

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## [How to get ticks elapsed by CPLEX solver with JuMP?](https://discourse.julialang.org/t/how-to-get-ticks-elapsed-by-cplex-solver-with-jump/58619)

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**Author:** [@Antell](https://discourse.julialang.org/u/Antell)\
**Replies:** 1\
**Last updated:** [April 5, 2021, 4:04pm UTC](https://discourse.julialang.org/t/how-to-get-ticks-elapsed-by-cplex-solver-with-jump/58619 "2021-04-05T16:04:43Z")

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I would like to call the getDetTime function from IBM Documentation on a model, in order to get the amount of deterministic ticks that have elapsed during a call to optimize!. I cannot figure out how to use the new CPLEX…

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## [Interpreting error message / stacktrace for CSV.File](https://discourse.julialang.org/t/interpreting-error-message-stacktrace-for-csv-file/58539)

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**Author:** [@George9000](https://discourse.julialang.org/u/George9000)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 3:19pm UTC](https://discourse.julialang.org/t/interpreting-error-message-stacktrace-for-csv-file/58539 "2021-04-05T15:19:36Z")

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System: macOS 10.15.7 Julia version 1.6 I use R heavily for data analysis in the life sciences and am slowly learning Julia for similar tasks with DataFrames.jl and CSV.jl. Recently I was tripped up by a small error an…

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## [JuMP optimize! call will very rarely violate model's time limit parameters by huge factors?](https://discourse.julialang.org/t/jump-optimize-call-will-very-rarely-violate-models-time-limit-parameters-by-huge-factors/58061)

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**Author:** [@Antell](https://discourse.julialang.org/u/Antell)\
**Replies:** 18\
**Last updated:** [April 5, 2021, 2:50pm UTC](https://discourse.julialang.org/t/jump-optimize-call-will-very-rarely-violate-models-time-limit-parameters-by-huge-factors/58061 "2021-04-05T14:50:41Z")

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I am doing research that involves incrementally loosening the relative parameter setting of a MIPS optimizer, in order to enable faster termination. Normally, this strategy works quite well. However, very rarely a call t…

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## [Attempting to print a string with an array](https://discourse.julialang.org/t/attempting-to-print-a-string-with-an-array/58614)

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**Author:** [@EMCP](https://discourse.julialang.org/u/EMCP)\
**Replies:** 7\
**Last updated:** [April 5, 2021, 2:47pm UTC](https://discourse.julialang.org/t/attempting-to-print-a-string-with-an-array/58614 "2021-04-05T14:47:13Z")

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please forgive this very newb question. I am attempting to run through the book “Neural Networks from Scratch with Python” … but with JuliaLang instead I want to do the following but it’s perhaps my bias towards python…

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## [Crash Windows 10](https://discourse.julialang.org/t/crash-windows-10/58616)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 2:39pm UTC](https://discourse.julialang.org/t/crash-windows-10/58616 "2021-04-05T14:39:52Z")

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This is the second time that I crash the Julia client when using LinearAlgebra’ish code. I can not provide a minimal working example yet, but I am working on it. I want to ask here early, because maybe that kind of issue…

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## [\[ANN\] Julia Code Generation With GraphQL](https://discourse.julialang.org/t/ann-julia-code-generation-with-graphql/58618)

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**Author:** [@markhalonen](https://discourse.julialang.org/u/markhalonen)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 2:01pm UTC](https://discourse.julialang.org/t/ann-julia-code-generation-with-graphql/58618 "2021-04-05T14:01:22Z")

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I published tooling that helps Julia clients that are querying a GraphQL api. If you are writing a bunch of GraphQL queries in Julia, this workflow should make life more enjoyable! https://lauriumlabs.com/blog/julia-co…

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## [Literate.jl: how to skip code parsing/testing for quick generation and preview of the documentation?](https://discourse.julialang.org/t/literate-jl-how-to-skip-code-parsing-testing-for-quick-generation-and-preview-of-the-documentation/58603)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 6\
**Last updated:** [April 5, 2021, 2:09pm UTC](https://discourse.julialang.org/t/literate-jl-how-to-skip-code-parsing-testing-for-quick-generation-and-preview-of-the-documentation/58603 "2021-04-05T14:09:04Z")

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I am using Literate —\> Documenter for the documentation of my package, but the inclusion of some tutorials makes the generation of the documentation taking a while. Sometimes I would just like to try how the documentati…

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## [Data science and neuroscience positions at Beacon Biosignals](https://discourse.julialang.org/t/data-science-and-neuroscience-positions-at-beacon-biosignals/58253)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 1\
**Last updated:** [April 5, 2021, 1:48pm UTC](https://discourse.julialang.org/t/data-science-and-neuroscience-positions-at-beacon-biosignals/58253 "2021-04-05T13:48:06Z")

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Beacon Biosignals is looking for some talented folks to join our team of dedicated people trying to make EEG analysis ubiquitous in healthcare. We’re using Julia as an integral part of our platform. We have a number of o…

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## [\[ANN\] ParallelUtilities: fast and easy parallel mapreduce for HPC clusters](https://discourse.julialang.org/t/ann-parallelutilities-fast-and-easy-parallel-mapreduce-for-hpc-clusters/58613)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 1:31pm UTC](https://discourse.julialang.org/t/ann-parallelutilities-fast-and-easy-parallel-mapreduce-for-hpc-clusters/58613 "2021-04-05T13:31:48Z")

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Evaluating a parallel mapreduce on an HPC cluster can be as simple as changing mapreduce to pmapreduce. This is a package that I had developed for my own research, but this might be useful to the community so I’m announc…

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## [Trouble adding packages: "The connection with the server was terminated abnormally"](https://discourse.julialang.org/t/trouble-adding-packages-the-connection-with-the-server-was-terminated-abnormally/58612)

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**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 1:26pm UTC](https://discourse.julialang.org/t/trouble-adding-packages-the-connection-with-the-server-was-terminated-abnormally/58612 "2021-04-05T13:26:43Z")

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How to solve this problem: Some packages have a happy installation and others do not! (@v1.6) pkg\> add Plots Updating registry at \`C:\\Users\\hermesr\\.julia\\registries\\General\` ┌ Warning: could not download https://p…

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