# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1454

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

**Page:** 1455

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## [JuliaCon 2021 CFP closes Mar 31st, 2021](https://discourse.julialang.org/t/juliacon-2021-cfp-closes-mar-31st-2021/54355)

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**Author:** [@nassarhuda](https://discourse.julialang.org/u/nassarhuda)\
**Replies:** 9\
**Last updated:** [March 18, 2021, 3:59pm UTC](https://discourse.julialang.org/t/juliacon-2021-cfp-closes-mar-31st-2021/54355 "2021-03-18T15:59:44Z")

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The JuliaCon 2021 Call for Proposals (CfP) is now open! The JuliaCon 2021 organizing committee invites the Julia community to submit proposals for the upcoming JuliaCon conference, which will take place from Wednesday …

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## [Getfield from package / module](https://discourse.julialang.org/t/getfield-from-package-module/57432)

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**Author:** [@stephenll](https://discourse.julialang.org/u/stephenll)\
**Replies:** 5\
**Last updated:** [March 18, 2021, 3:41pm UTC](https://discourse.julialang.org/t/getfield-from-package-module/57432 "2021-03-18T15:41:54Z")

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In a package I created, I am trying to call a function with a string, and using getfield, return a function from another package. The other package has been properly added to my package, and I could use the functions if…

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## [REPL and monitor width](https://discourse.julialang.org/t/repl-and-monitor-width/57256)

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**Author:** [@tbeason](https://discourse.julialang.org/u/tbeason)\
**Replies:** 6\
**Last updated:** [March 18, 2021, 3:29pm UTC](https://discourse.julialang.org/t/repl-and-monitor-width/57256 "2021-03-18T15:29:21Z")

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Considering buying one of those ultra-wide monitors. To those that have one already (because I’m sure someone here does), does the REPL scale the full width? Could I just immerse myself in Julia? Bonus points for screen…

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## [Preprocessing function arguments](https://discourse.julialang.org/t/preprocessing-function-arguments/57474)

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**Author:** [@huchiayu0517](https://discourse.julialang.org/u/huchiayu0517)\
**Replies:** 6\
**Last updated:** [March 18, 2021, 3:14pm UTC](https://discourse.julialang.org/t/preprocessing-function-arguments/57474 "2021-03-18T15:14:09Z")

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I have a working code like the following: function test(a,b) c = a + b d = a - b e = c + 2 \* d end but I now want to sometimes make b a constant s.t. const b = 1.5 function test(a) c…

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## [How to provide two versions of some quantities to the user. Can they unload a module?](https://discourse.julialang.org/t/how-to-provide-two-versions-of-some-quantities-to-the-user-can-they-unload-a-module/57325)

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**Author:** [@aramirezreyes](https://discourse.julialang.org/u/aramirezreyes)\
**Replies:** 3\
**Last updated:** [March 18, 2021, 3:15pm UTC](https://discourse.julialang.org/t/how-to-provide-two-versions-of-some-quantities-to-the-user-can-they-unload-a-module/57325 "2021-03-18T15:15:37Z")

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Hi! I wrote this on the Slack but I think here may be a good fit. I have a package that contains some physical constants (for example g, the acceleration of gravity). I provide units with the constants through Unitful.j…

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## [Can you solve a NeuralODEMM on GPU?](https://discourse.julialang.org/t/can-you-solve-a-neuralodemm-on-gpu/57480)

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**Author:** [@bad\_at\_math](https://discourse.julialang.org/u/bad_at_math)\
**Replies:** 0\
**Last updated:** [March 18, 2021, 3:03pm UTC](https://discourse.julialang.org/t/can-you-solve-a-neuralodemm-on-gpu/57480 "2021-03-18T15:03:01Z")

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I’m trying to solve a neural ODE with a mass matrix using CUDA. Is this possible, or are the required solvers not GPU-compatible? I can define a NeuralODEMM with a CuArray Chain, but I get the error ERROR: LoadError: sca…

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## [Variables when passed to functions](https://discourse.julialang.org/t/variables-when-passed-to-functions/57476)

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**Author:** [@anon60034542](https://discourse.julialang.org/u/anon60034542)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 1:43pm UTC](https://discourse.julialang.org/t/variables-when-passed-to-functions/57476 "2021-03-18T13:43:27Z")

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function add!(character\_storage ::Dict{String,Int32}, acquired :: Pair{String,Int32}) push!(character\_storage,acquired) end items = Dict{String,Int32}() orb\_of\_health :: Pair = ("Orb" =\> 10) According to the documenta…

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## [Is "import" required for user-defined modules?](https://discourse.julialang.org/t/is-import-required-for-user-defined-modules/57352)

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**Author:** [@PeterB](https://discourse.julialang.org/u/PeterB)\
**Replies:** 3\
**Last updated:** [March 18, 2021, 2:51pm UTC](https://discourse.julialang.org/t/is-import-required-for-user-defined-modules/57352 "2021-03-18T14:51:38Z")

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When using modules, is “import” or “using” needed? The reason I ask is that in the following toy example, according to my reading of the documentation, an “import” (or “using”) statement is required. But the program runs…

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## [Examples of a database to manage simulation result files](https://discourse.julialang.org/t/examples-of-a-database-to-manage-simulation-result-files/55063)

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**Author:** [@Olivier\_Merchiers](https://discourse.julialang.org/u/Olivier_Merchiers)\
**Replies:** 4\
**Last updated:** [March 18, 2021, 2:43pm UTC](https://discourse.julialang.org/t/examples-of-a-database-to-manage-simulation-result-files/55063 "2021-03-18T14:43:33Z")

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Hello everyone, I use DrWatson.jl to manage my scientific projects. The default way to manage files containing simulation results, is to put the list of parameters in the filename. This works well for small projects, b…

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## [Why does DiffEqFlux.NeuralODEMM require a constraint equation and a mass matrix?](https://discourse.julialang.org/t/why-does-diffeqflux-neuralodemm-require-a-constraint-equation-and-a-mass-matrix/57428)

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**Author:** [@bad\_at\_math](https://discourse.julialang.org/u/bad_at_math)\
**Replies:** 3\
**Last updated:** [March 18, 2021, 2:24pm UTC](https://discourse.julialang.org/t/why-does-diffeqflux-neuralodemm-require-a-constraint-equation-and-a-mass-matrix/57428 "2021-03-18T14:24:40Z")

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Hello everyone! I’m looking at the “Enforcing physical constraints via universal differential-algebraic equations” example (https://diffeqflux.sciml.ai/dev/examples/physical\_constraints/), which trains a neural ordinary…

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## [Help speeding up FFT processing code](https://discourse.julialang.org/t/help-speeding-up-fft-processing-code/57219)

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**Author:** [@mihalybaci](https://discourse.julialang.org/u/mihalybaci)\
**Replies:** 9\
**Last updated:** [March 18, 2021, 2:24pm UTC](https://discourse.julialang.org/t/help-speeding-up-fft-processing-code/57219 "2021-03-18T14:24:01Z")

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Hi all, I have a three functions that I have translated from Python and would like some assistance in improving their performance. The full working code is: using FFTW """ Implementation of numpy.roll """ roll(vec, num…

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## [Make function accept an array of strings and return an array of strings](https://discourse.julialang.org/t/make-function-accept-an-array-of-strings-and-return-an-array-of-strings/57473)

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**Author:** [@sonicrules1234](https://discourse.julialang.org/u/sonicrules1234)\
**Replies:** 5\
**Last updated:** [March 18, 2021, 1:56pm UTC](https://discourse.julialang.org/t/make-function-accept-an-array-of-strings-and-return-an-array-of-strings/57473 "2021-03-18T13:56:47Z")

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I’m working on a google translate package, and I’ve got the translating part, but I want a function that will do a batch translate. function batchtranslate(inputstrings::Array{String,1}, lang\_tgt="auto"::String, lang\_sr…

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## [@edit does not work on my system](https://discourse.julialang.org/t/edit-does-not-work-on-my-system/57431)

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**Author:** [@linwaytin](https://discourse.julialang.org/u/linwaytin)\
**Replies:** 4\
**Last updated:** [March 18, 2021, 1:49pm UTC](https://discourse.julialang.org/t/edit-does-not-work-on-my-system/57431 "2021-03-18T13:49:00Z")

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I want to try the macro @edit but I got julia\> @edit 3+5 ERROR: could not find source file for function Stacktrace: \[1\] edit(::Nothing, ::Int32) at /build/julia/src/julia-1.5.3/usr/share/julia/stdlib/v1.5/InteractiveUt…

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## [Is it possible to do a \`mapreduce\` with multiple arrays while broadcasting over so](https://discourse.julialang.org/t/is-it-possible-to-do-a-mapreduce-with-multiple-arrays-while-broadcasting-over-so/57433)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 4\
**Last updated:** [March 18, 2021, 1:44pm UTC](https://discourse.julialang.org/t/is-it-possible-to-do-a-mapreduce-with-multiple-arrays-while-broadcasting-over-so/57433 "2021-03-18T13:44:57Z")

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Is it possible to do a mapreduce with multiple arrays while broadcasting over some dimensions? Something like this U = rand(5, 5, 5) Δ = rand(1, 1, 5) mapreduce((u, Δx) -\> u / Δx, max, U, Δ) where I really want to find…

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## [The Julia Language has been accepted for GSoC 2021](https://discourse.julialang.org/t/the-julia-language-has-been-accepted-for-gsoc-2021/57477)

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**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 0\
**Last updated:** [March 18, 2021, 1:37pm UTC](https://discourse.julialang.org/t/the-julia-language-has-been-accepted-for-gsoc-2021/57477 "2021-03-18T13:37:29Z")

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Hey all! We are delighted to announce that the Julia Language has been accepted as a mentoring organization for Google Summer of Code 2021. This year’s programs features a revamped project timeline (half as long as us…

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## [Contour plot for non-rectangular domain](https://discourse.julialang.org/t/contour-plot-for-non-rectangular-domain/57381)

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**Author:** [@Gus\_Hart](https://discourse.julialang.org/u/Gus_Hart)\
**Replies:** 6\
**Last updated:** [March 18, 2021, 1:25pm UTC](https://discourse.julialang.org/t/contour-plot-for-non-rectangular-domain/57381 "2021-03-18T13:25:24Z")

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There was a previous thread on this, but the use case was too different from mine to be informative. I have a function defined over a triangle and would like to plot it as a contour plot but only in the triangular domai…

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## [Is there a simple way to get the logging macros to print timestamps?i.e.\`\`\`julia](https://discourse.julialang.org/t/is-there-a-simple-way-to-get-the-logging-macros-to-print-timestamps-i-e-julia/57472)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 1:12pm UTC](https://discourse.julialang.org/t/is-there-a-simple-way-to-get-the-logging-macros-to-print-timestamps-i-e-julia/57472 "2021-03-18T13:12:37Z")

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Is there a simple way to get the logging macros to print timestamps? i.e. julia&gt; @info "hello" 2021-03-18T09:08:24.462 \[ Info: hello Note that the original poster on Slack cannot see your response here on Discourse…

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## [Yet Another Component Example](https://discourse.julialang.org/t/yet-another-component-example/57318)

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**Author:** [@lungd](https://discourse.julialang.org/u/lungd)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 12:13pm UTC](https://discourse.julialang.org/t/yet-another-component-example/57318 "2021-03-18T12:13:47Z")

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As far as I know, there are some WIP tutorials describing how to create components and how they can be merged. I was not sure where to put the following, maybe it would fit better into an existing github issue (e.g. Conn…

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## [Non-diagonal noise correlation matrix](https://discourse.julialang.org/t/non-diagonal-noise-correlation-matrix/57393)

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**Author:** [@Amir\_Abbasi](https://discourse.julialang.org/u/Amir_Abbasi)\
**Replies:** 0\
**Last updated:** [March 17, 2021, 3:55pm UTC](https://discourse.julialang.org/t/non-diagonal-noise-correlation-matrix/57393 "2021-03-17T15:55:05Z")

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Hi all! I am newbie to julia and I am playing with it to solve SDE systems, numerically. I had a look at Non-diagonal noise Tutorial (Example No. 4) https://diffeq.sciml.ai/stable/tutorials/sde\_example/, but still some…

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## [Neuroscientists using DifferentialEquations.jl ecosystem?](https://discourse.julialang.org/t/neuroscientists-using-differentialequations-jl-ecosystem/31871)

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**Author:** [@wsphillips](https://discourse.julialang.org/u/wsphillips)\
**Replies:** 25\
**Last updated:** [March 18, 2021, 11:32am UTC](https://discourse.julialang.org/t/neuroscientists-using-differentialequations-jl-ecosystem/31871 "2021-03-18T11:32:44Z")

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I am curious who might be working with the DiffEq packages to do single neuron cell modeling up to small network simulations using Hodgkin Huxley or similar models, either single or multi-compartment, etc. If you’re out…

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## [Plot group size after running groupby](https://discourse.julialang.org/t/plot-group-size-after-running-groupby/57457)

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**Author:** [@alessio](https://discourse.julialang.org/u/alessio)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 11:14am UTC](https://discourse.julialang.org/t/plot-group-size-after-running-groupby/57457 "2021-03-18T11:14:30Z")

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I have a DataFrame with a :group column and did a gb = groupby(df, :group) I would like to plot the group sizes vs. group id. For example, for group gb\[1\] on the x-axis I would like to plot nrow(gb\[1\]) on the y-axis H…

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## [Browser problems displaying maths Unicode characters](https://discourse.julialang.org/t/browser-problems-displaying-maths-unicode-characters/56948)

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**Author:** [@cormullion](https://discourse.julialang.org/u/cormullion)\
**Replies:** 23\
**Last updated:** [March 18, 2021, 10:39am UTC](https://discourse.julialang.org/t/browser-problems-displaying-maths-unicode-characters/56948 "2021-03-18T10:39:58Z")

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After keno uploaded a short code snippet to a github gist I noticed that my browser (Safari on macOS) wasn’t rendering some of his code correctly there, particularly the glyph compositions (eg where two characters such a…

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## [Making a custom distribution with value as parametric type](https://discourse.julialang.org/t/making-a-custom-distribution-with-value-as-parametric-type/57454)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [March 18, 2021, 10:38am UTC](https://discourse.julialang.org/t/making-a-custom-distribution-with-value-as-parametric-type/57454 "2021-03-18T10:38:26Z")

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Hello, I’m trying to get my head around types with a value parameter. Here I’m trying to implement a wrapper to the Normal distribution type where two distributions must have the same Coefficient of Variability (CV) to b…

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## [Best implementation for semiclassical dynamics in Julia](https://discourse.julialang.org/t/best-implementation-for-semiclassical-dynamics-in-julia/57423)

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**Author:** [@ErikPillon](https://discourse.julialang.org/u/ErikPillon)\
**Replies:** 5\
**Last updated:** [March 18, 2021, 10:20am UTC](https://discourse.julialang.org/t/best-implementation-for-semiclassical-dynamics-in-julia/57423 "2021-03-18T10:20:53Z")

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Dear all, I’m a Julia user since 2017 and after getting familiar with multiple dispatch and mutable structures, I finally found the courage to interact for the first time with the Julia community. Here’s my question. D…

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## [Implementing the hydrogen atom?](https://discourse.julialang.org/t/implementing-the-hydrogen-atom/57455)

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**Author:** [@volkerkarle](https://discourse.julialang.org/u/volkerkarle)\
**Replies:** 0\
**Last updated:** [March 18, 2021, 10:15am UTC](https://discourse.julialang.org/t/implementing-the-hydrogen-atom/57455 "2021-03-18T10:15:27Z")

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Hi folks, Is there a package dealing with problems from atomic physics i.e. an implementation of the hydrogen wave function, relativistic corrections etc. ? I know there is UnitfulAtomic.jl, but that is only for the cor…

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## [Distributed, AllReduce, and Distributed Training](https://discourse.julialang.org/t/distributed-allreduce-and-distributed-training/56110)

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**Author:** [@asaxton](https://discourse.julialang.org/u/asaxton)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 9:56am UTC](https://discourse.julialang.org/t/distributed-allreduce-and-distributed-training/56110 "2021-03-18T09:56:51Z")

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Continuing the discussion from Julia Distributed, AllReduce, and Distributed Training: I’m working with Distributed Julia on multiple hosts and want to write some code that does distributed training with a machine learn…

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## [How to sum the chunks of a distributed array using a binary reduction tree?](https://discourse.julialang.org/t/how-to-sum-the-chunks-of-a-distributed-array-using-a-binary-reduction-tree/57288)

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**Author:** [@matthiasbe](https://discourse.julialang.org/u/matthiasbe)\
**Replies:** 1\
**Last updated:** [March 18, 2021, 9:56am UTC](https://discourse.julialang.org/t/how-to-sum-the-chunks-of-a-distributed-array-using-a-binary-reduction-tree/57288 "2021-03-18T09:56:06Z")

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Hi, I use the reduce() function to sum all the parts of a distributed array. function reduce(A::DArray{Float64,2})::Int # Sum reduction : sums all partitions of A # The result is on aggregator\_worker aggregator\_w…

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## [Is it time for a native Julia LP(Simplex) solver?](https://discourse.julialang.org/t/is-it-time-for-a-native-julia-lp-simplex-solver/21639)

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**Author:** [@ndinsmore](https://discourse.julialang.org/u/ndinsmore)\
**Replies:** 44\
**Last updated:** [March 18, 2021, 8:58am UTC](https://discourse.julialang.org/t/is-it-time-for-a-native-julia-lp-simplex-solver/21639 "2021-03-18T08:58:57Z")

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For the last few months, I have been coming up to speed on both Linear Programming with Jump.jl using Clp.jl, Cbc.jl, and GLPK.jl. I have made some minor PRs to a few of the projects in order to improve the capability t…

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## [Error installing GR in Julia 1.6 RC2 (Windows x64)](https://discourse.julialang.org/t/error-installing-gr-in-julia-1-6-rc2-windows-x64/57443)

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**Author:** [@mobius-eng](https://discourse.julialang.org/u/mobius-eng)\
**Replies:** 6\
**Last updated:** [March 18, 2021, 8:54am UTC](https://discourse.julialang.org/t/error-installing-gr-in-julia-1-6-rc2-windows-x64/57443 "2021-03-18T08:54:40Z")

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I realize things will probably break in the transition from 1.5 to 1.6, but I didn’t see anyone reporting an issue like this on GitHub. So, I am just checking whether it is something specific to my case and if there is s…

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## [Conditional evaluation of lines](https://discourse.julialang.org/t/conditional-evaluation-of-lines/57426)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 8\
**Last updated:** [March 18, 2021, 7:57am UTC](https://discourse.julialang.org/t/conditional-evaluation-of-lines/57426 "2021-03-18T07:57:50Z")

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I have a function f that creates and filsl a vector of n components with the result of expensive functions gi. I am interested in having f depend on n. I have tried the following, but I’m wondering if there is a better, …

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