# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1506

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

**Page:** 1507

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## [Computing Flux.gradient change the model](https://discourse.julialang.org/t/computing-flux-gradient-change-the-model/54284)

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**Author:** [@anon74562486](https://discourse.julialang.org/u/anon74562486)\
**Replies:** 10\
**Last updated:** [January 31, 2021, 7:54pm UTC](https://discourse.julialang.org/t/computing-flux-gradient-change-the-model/54284 "2021-01-31T19:54:09Z")

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I don’t speak English well, so sorry for the mistakes. I have an exercise of differential programming. I have an image taken from MNIST and a fully connected NN that classifies correctly that image. Then I want to mod…

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## [Unsatisfiable requirements detected for package](https://discourse.julialang.org/t/unsatisfiable-requirements-detected-for-package/54336)

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**Author:** [@iamsuddhasattwa](https://discourse.julialang.org/u/iamsuddhasattwa)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 7:04pm UTC](https://discourse.julialang.org/t/unsatisfiable-requirements-detected-for-package/54336 "2021-01-31T19:04:38Z")

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I am getting the above error when trying to install the basic DataStructures package. I tries \] gc but that did not work. julia\> VERSION v"1.2.0" julia\> Pkg.add("DataStructures") Resolving package versions... ERROR: Un…

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## [4D plotting](https://discourse.julialang.org/t/4d-plotting/54138)

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**Author:** [@Ruchitha\_Kumar](https://discourse.julialang.org/u/Ruchitha_Kumar)\
**Replies:** 8\
**Last updated:** [January 31, 2021, 7:03pm UTC](https://discourse.julialang.org/t/4d-plotting/54138 "2021-01-31T19:03:12Z")

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How to plot a 4D graph in julia? Can someone please help with this? Thanks in advance

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## [Julia VS Code extension version v0.17 released](https://discourse.julialang.org/t/julia-vs-code-extension-version-v0-17-released/42865)

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**Author:** [@davidanthoff](https://discourse.julialang.org/u/davidanthoff)\
**Replies:** 7\
**Last updated:** [January 31, 2021, 5:27pm UTC](https://discourse.julialang.org/t/julia-vs-code-extension-version-v0-17-released/42865 "2021-01-31T17:27:18Z")

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We just released v0.17 of the Julia VS Code extension to the marketplace. Global variable support in the debugger variable explorer The Variables pane in the integrated debugger now supports global variables: Global…

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## [Native Qp solver?](https://discourse.julialang.org/t/native-qp-solver/54304)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 1\
**Last updated:** [January 31, 2021, 4:48pm UTC](https://discourse.julialang.org/t/native-qp-solver/54304 "2021-01-31T16:48:10Z")

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Hey, I’m used to OSQP for QP solving in Float64, which had a lot of wrappers for all languages. However, Julia has a deep understanding of what Is a real number, and I’d like to solve QP for any real number, including …

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## [When working on a project (not a package, not intention of re-use), I started usin](https://discourse.julialang.org/t/when-working-on-a-project-not-a-package-not-intention-of-re-use-i-started-usin/54331)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [January 31, 2021, 4:28pm UTC](https://discourse.julialang.org/t/when-working-on-a-project-not-a-package-not-intention-of-re-use-i-started-usin/54331 "2021-01-31T16:28:21Z")

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When working on a project (not a package, not intention of re-use), I started using Revise and includet. Once my project got larger, I figured it was best to put it into a module. Everything is in functions already. I do…

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## [I’m trying to create a docker container that has some of the packages already inst](https://discourse.julialang.org/t/i-m-trying-to-create-a-docker-container-that-has-some-of-the-packages-already-inst/54324)

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**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [January 31, 2021, 3:26pm UTC](https://discourse.julialang.org/t/i-m-trying-to-create-a-docker-container-that-has-some-of-the-packages-already-inst/54324 "2021-01-31T15:26:29Z")

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I’m trying to create a docker container that has some of the packages already installed for later Julia execution. The idea is that the current directory is something you want to run in docker, and it has a Project.toml…

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## [Stack Overflow Error in Julia itself (type-inference)?](https://discourse.julialang.org/t/stack-overflow-error-in-julia-itself-type-inference/54228)

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**Author:** [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 2:56pm UTC](https://discourse.julialang.org/t/stack-overflow-error-in-julia-itself-type-inference/54228 "2021-01-31T14:56:31Z")

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I have done the following test in Julia 1.5.3 and Julia 1.6.0-beta1. $ git clone https://github.com/henriquebecker91/GuillotineModels.jl $ cd GuillotineModels.jl/examples $ git checkout 2c979b7f $ wget https://pastebin.…

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## [L-BFGS returns a NaN gradient when providing analytical gradient. BFGS shows no issues](https://discourse.julialang.org/t/l-bfgs-returns-a-nan-gradient-when-providing-analytical-gradient-bfgs-shows-no-issues/54196)

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**Author:** [@juandarias](https://discourse.julialang.org/u/juandarias)\
**Replies:** 1\
**Last updated:** [January 31, 2021, 1:16pm UTC](https://discourse.julialang.org/t/l-bfgs-returns-a-nan-gradient-when-providing-analytical-gradient-bfgs-shows-no-issues/54196 "2021-01-31T13:16:23Z")

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Observations When providing an analytical gradient for optimization using LBFGS with boxed constraints, the optimizer fails occasionally due to gradient becoming NaN, i.e. g(x) = \[Nan, ..., Nan\]. The analytical gradien…

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## [Changing color/colorbar limits in a heat map in Plots.jl](https://discourse.julialang.org/t/changing-color-colorbar-limits-in-a-heat-map-in-plots-jl/54277)

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**Author:** [@Peter\_Staab](https://discourse.julialang.org/u/Peter_Staab)\
**Replies:** 3\
**Last updated:** [January 31, 2021, 12:54pm UTC](https://discourse.julialang.org/t/changing-color-colorbar-limits-in-a-heat-map-in-plots-jl/54277 "2021-01-31T12:54:37Z")

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I’m looking to change the range of colors on a heat map. For example: hm1 = heatmap(rand(20,20),aspect\_ratio=:equal) hm2 = heatmap(0.9\*rand(20,20),aspect\_ratio=:equal) plot(hm1,hm2) resulting in: defaults to 0-\>1 …

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## [Program design: Types with only fixed Parameters?](https://discourse.julialang.org/t/program-design-types-with-only-fixed-parameters/54316)

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**Author:** [@florian](https://discourse.julialang.org/u/florian)\
**Replies:** 1\
**Last updated:** [January 31, 2021, 12:42pm UTC](https://discourse.julialang.org/t/program-design-types-with-only-fixed-parameters/54316 "2021-01-31T12:42:45Z")

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Hi everyone, I’m trying to get used to programming with custom types and am in the following situation: Suppose I want to write a Program that calls an API, and there are different types of calls. First, I made a struc…

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## [Eltype vs typeof what is the difference?](https://discourse.julialang.org/t/eltype-vs-typeof-what-is-the-difference/54319)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 3\
**Last updated:** [January 31, 2021, 12:27pm UTC](https://discourse.julialang.org/t/eltype-vs-typeof-what-is-the-difference/54319 "2021-01-31T12:27:48Z")

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Hey Julianners, I want to understand what is the use of eltype. Is it always equal with: x not iterable: eltype(x) == typeof(x) x is iterable: eltype(x) == typeof(x\[1\]) and some size checking? Or eltype if specifica…

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## [Changing the background color of a 3D Scene in Makie](https://discourse.julialang.org/t/changing-the-background-color-of-a-3d-scene-in-makie/53490)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 8\
**Last updated:** [January 31, 2021, 10:34am UTC](https://discourse.julialang.org/t/changing-the-background-color-of-a-3d-scene-in-makie/53490 "2021-01-31T10:34:13Z")

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How can I make the background color of a (3D) scene contained within an LScene ? Including backgroundcolor=:black in the scenekw arg doesn’t seem to do it, nor does setting the attribute directly on lscene.scene . Howeve…

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## [Bukdu, how to display favicon.ico](https://discourse.julialang.org/t/bukdu-how-to-display-favicon-ico/54123)

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**Author:** [@rbontekoe](https://discourse.julialang.org/u/rbontekoe)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 10:33am UTC](https://discourse.julialang.org/t/bukdu-how-to-display-favicon-ico/54123 "2021-01-31T10:33:03Z")

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I have built a simple website with Bukdu. It works fine, except that it gives a 404 error message because it does not find favicon.ico. favicon.ico is stored in the base directory. Bukdu Listening on 0.0.0.0:8004 INFO: …

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## [Obtaining the last element of a ProductIterator](https://discourse.julialang.org/t/obtaining-the-last-element-of-a-productiterator/54259)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 3\
**Last updated:** [January 31, 2021, 10:16am UTC](https://discourse.julialang.org/t/obtaining-the-last-element-of-a-productiterator/54259 "2021-01-31T10:16:09Z")

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Currently there is no way to obtain the last element of an iterator product, for example: julia\> it = Iterators.product(1:3, 2:3) Base.Iterators.ProductIterator{Tuple{UnitRange{Int64}, UnitRange{Int64}}}((1:3, 2:3)) ju…

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## [Makie recipe usage](https://discourse.julialang.org/t/makie-recipe-usage/54292)

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**Author:** [@henry2004y](https://discourse.julialang.org/u/henry2004y)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 9:06am UTC](https://discourse.julialang.org/t/makie-recipe-usage/54292 "2021-01-31T09:06:17Z")

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I read about a post makie-recipe-specialisation-for-specific-types for plotting customized types from Makie. The official document also has a Plot-Recipes section, but I still do not understand how to use it. Additionall…

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## [If almost all ODE solvers fail, how can we trust the results from the other solvers?](https://discourse.julialang.org/t/if-almost-all-ode-solvers-fail-how-can-we-trust-the-results-from-the-other-solvers/54299)

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**Author:** [@Xiaodong\_Liang](https://discourse.julialang.org/u/Xiaodong_Liang)\
**Replies:** 6\
**Last updated:** [January 31, 2021, 8:13am UTC](https://discourse.julialang.org/t/if-almost-all-ode-solvers-fail-how-can-we-trust-the-results-from-the-other-solvers/54299 "2021-01-31T08:13:32Z")

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I want to introduce Julia to one course. We have been using MATLAB in this course for many years, which are very robust. For these special problems, I tried Python and it seems not as robust as MATLAB (I am also a beginn…

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## [ODBC.DSN(dsn, user, password) error: DSN not defined](https://discourse.julialang.org/t/odbc-dsn-dsn-user-password-error-dsn-not-defined/48087)

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**Author:** [@indycdrom](https://discourse.julialang.org/u/indycdrom)\
**Replies:** 9\
**Last updated:** [January 31, 2021, 8:04am UTC](https://discourse.julialang.org/t/odbc-dsn-dsn-user-password-error-dsn-not-defined/48087 "2021-01-31T08:04:53Z")

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hi, I have been using ODBC.DSN(dsn, user, password) to connect to oracle database using ODBC.jl (v0.8.1) and Julia 1.2.0 with no issue. But when I upgraded to Julia 1.5.2 and ODBC (1.0.4), I got an error saying that DSN…

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## [Comparing 2 equilibrium values (competitive and centralized) at general equilibrium: can I compare only the first order conditions?](https://discourse.julialang.org/t/comparing-2-equilibrium-values-competitive-and-centralized-at-general-equilibrium-can-i-compare-only-the-first-order-conditions/54124)

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**Author:** [@axelle](https://discourse.julialang.org/u/axelle)\
**Replies:** 6\
**Last updated:** [January 31, 2021, 7:15am UTC](https://discourse.julialang.org/t/comparing-2-equilibrium-values-competitive-and-centralized-at-general-equilibrium-can-i-compare-only-the-first-order-conditions/54124 "2021-01-31T07:15:50Z")

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I have a rather complex model where analytical solutions do not seem achievable (I also tried symbolic solving and Matlab and Python and could not find any) so that I cannot get an explicit expression for my equilibrim v…

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## [Serialize a Instance of mutable type into Json using JSON3?](https://discourse.julialang.org/t/serialize-a-instance-of-mutable-type-into-json-using-json3/54300)

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**Author:** [@DataPsycho](https://discourse.julialang.org/u/DataPsycho)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 5:02am UTC](https://discourse.julialang.org/t/serialize-a-instance-of-mutable-type-into-json-using-json3/54300 "2021-01-31T05:02:34Z")

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Hi, Lets say i have defined a struct and StructType method for unmarshaling from json string as follows: mutable struct Request from::String message::String requesttime::String end # Outer Constructor func…

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## [Splitting Int8s?](https://discourse.julialang.org/t/splitting-int8s/54290)

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**Author:** [@Ian\_Slagle](https://discourse.julialang.org/u/Ian_Slagle)\
**Replies:** 12\
**Last updated:** [January 31, 2021, 4:31am UTC](https://discourse.julialang.org/t/splitting-int8s/54290 "2021-01-31T04:31:00Z")

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I have a struct that is copied a lot in my program, so reducing the size of this struct has very noticeable impacts on performance. Of the variables I have, some are an integer (currently represented as Int8) that are bo…

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## [Error running distributed code inside of a module](https://discourse.julialang.org/t/error-running-distributed-code-inside-of-a-module/54283)

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**Author:** [@patrick-kidger](https://discourse.julialang.org/u/patrick-kidger)\
**Replies:** 6\
**Last updated:** [January 31, 2021, 4:20am UTC](https://discourse.julialang.org/t/error-running-distributed-code-inside-of-a-module/54283 "2021-01-31T04:20:27Z")

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The following works just fine: using Distributed procs = addprocs(10) futures = \[\] for proc in procs push!(futures, @spawnat proc sleep(2)) end for fut in futures fetch(fut) end The following: module A using D…

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## [How to send a simple "GET" or "POST" with parameters](https://discourse.julialang.org/t/how-to-send-a-simple-get-or-post-with-parameters/54125)

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**Author:** [@nuclear718](https://discourse.julialang.org/u/nuclear718)\
**Replies:** 2\
**Last updated:** [January 31, 2021, 2:41am UTC](https://discourse.julialang.org/t/how-to-send-a-simple-get-or-post-with-parameters/54125 "2021-01-31T02:41:14Z")

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The data provider has an example in python: url = "xxx" parameter = { "dataset": "TaiwanStockInfo", "token": "", # 參考登入，獲取金鑰 } resp = requests.get(url, params=parameter) How to translate these simple python cod…

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## [Newton method within factor 1.5 of inv(x)](https://discourse.julialang.org/t/newton-method-within-factor-1-5-of-inv-x/54260)

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**Author:** [@ettersi](https://discourse.julialang.org/u/ettersi)\
**Replies:** 6\
**Last updated:** [January 31, 2021, 1:57am UTC](https://discourse.julialang.org/t/newton-method-within-factor-1-5-of-inv-x/54260 "2021-01-31T01:57:07Z")

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I was playing around with Newton’s method the other day and was mind-blown when I realised that a fairly straightforward Julia implementation of Newton’s method applied to f(x) = 1/x - y comes within roughly a factor 1.5…

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## [Passing password from Base.getpass\\Base.winprompt to HTTP.request](https://discourse.julialang.org/t/passing-password-from-base-getpass-base-winprompt-to-http-request/53579)

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**Author:** [@dannofthursday](https://discourse.julialang.org/u/dannofthursday)\
**Replies:** 6\
**Last updated:** [January 31, 2021, 1:36am UTC](https://discourse.julialang.org/t/passing-password-from-base-getpass-base-winprompt-to-http-request/53579 "2021-01-31T01:36:38Z")

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I am trying to convert a few python scripts to julia. I wrote a simple script, in Python, wherein it asks for the username and password and uses them with Basic Authentication to request data from our company website. Th…

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## [Profiled JIT dump lacks machine code](https://discourse.julialang.org/t/profiled-jit-dump-lacks-machine-code/54307)

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**Author:** [@bicycle1885](https://discourse.julialang.org/u/bicycle1885)\
**Replies:** 0\
**Last updated:** [January 31, 2021, 12:52am UTC](https://discourse.julialang.org/t/profiled-jit-dump-lacks-machine-code/54307 "2021-01-31T00:52:24Z")

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Hi all, I would like to profile Julia functions at instruction level using Linux perf. However, I cannot see disassembled machine code in the result. As you can see below, the disassembled code just after julia\_partitio…

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## [Existing package for basic mesh manipulation?](https://discourse.julialang.org/t/existing-package-for-basic-mesh-manipulation/53941)

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**Author:** [@OliverEvans96](https://discourse.julialang.org/u/OliverEvans96)\
**Replies:** 16\
**Last updated:** [January 31, 2021, 12:13am UTC](https://discourse.julialang.org/t/existing-package-for-basic-mesh-manipulation/53941 "2021-01-31T00:13:18Z")

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Hi all, Just a quick question: is there a package out there that I can use to perform basic mesh manipulations such as subdivide, extrude, etc.? I see Meshes.jl, which has some triangulation functions, but I don’t see m…

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## [Start Julia directly in shell\> or pkg\> mode?](https://discourse.julialang.org/t/start-julia-directly-in-shell-or-pkg-mode/54296)

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**Author:** [@QuantumBits](https://discourse.julialang.org/u/QuantumBits)\
**Replies:** 5\
**Last updated:** [January 30, 2021, 11:24pm UTC](https://discourse.julialang.org/t/start-julia-directly-in-shell-or-pkg-mode/54296 "2021-01-30T23:24:29Z")

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Hi! Is it possible to start a Julia REPL from the command line directly in shell\> or pkg\> mode without having to type ; or \], respectively, after the REPL loads? For example, something like: $ julia julia\> $ julia --she…

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## [.xls Files on Julia](https://discourse.julialang.org/t/xls-files-on-julia/54245)

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**Author:** [@Rodrigo\_Roa](https://discourse.julialang.org/u/Rodrigo_Roa)\
**Replies:** 5\
**Last updated:** [January 30, 2021, 9:45pm UTC](https://discourse.julialang.org/t/xls-files-on-julia/54245 "2021-01-30T21:45:32Z")

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Hi, im looking for a package that allows you read a .xls file, if possible similar to the ones that works whit .xlsx.

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## [On moderation and edits](https://discourse.julialang.org/t/on-moderation-and-edits/54287)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 11\
**Last updated:** [January 30, 2021, 8:22pm UTC](https://discourse.julialang.org/t/on-moderation-and-edits/54287 "2021-01-30T20:22:30Z")

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:warning: Warning: about to get something off my chest, this isn’t a technical post! :blush: Ok, so first off all I totally agree that the community should strive to avoid some of the, shall we say, less sociable intera…

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