# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1234

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

**Page:** 1235

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## [Unexpected behaviour from Continuous Callback in DifferentialEquations.jl simulating Lotka-Volterra Dynamics](https://discourse.julialang.org/t/unexpected-behaviour-from-continuous-callback-in-differentialequations-jl-simulating-lotka-volterra-dynamics/69404)

<div class="topic-metadata">

**Author:** [@colebrookson](https://discourse.julialang.org/u/colebrookson)\
**Replies:** 6\
**Last updated:** [October 19, 2021, 3:32am UTC](https://discourse.julialang.org/t/unexpected-behaviour-from-continuous-callback-in-differentialequations-jl-simulating-lotka-volterra-dynamics/69404 "2021-10-19T03:32:04Z")

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Hi there, So I’m using a ContinuousCallback method to simulate a simple Lotka-Volterra consumer-resource system of equations: \\frac{dC}{dt} = (\\alpha - \\beta R)C \\frac{dR}{dt} = (-\\gamma + \\delta C)R My goal is to …

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## [Unexpected error in runtime](https://discourse.julialang.org/t/unexpected-error-in-runtime/69473)

<div class="topic-metadata">

**Author:** [@goerch](https://discourse.julialang.org/u/goerch)\
**Replies:** 3\
**Last updated:** [October 19, 2021, 1:40am UTC](https://discourse.julialang.org/t/unexpected-error-in-runtime/69473 "2021-10-19T01:40:55Z")

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I see this on 1.6.3: Internal error: encountered unexpected error in runtime: BoundsError(a=svec(), i=0) getindex at .\\essentials.jl:589 \[inlined\] unswitchtupleunion at .\\compiler\\typeutils.jl:219 getfield\_elim\_pass! at…

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## [Using recently updated packages with earlier versions of julia](https://discourse.julialang.org/t/using-recently-updated-packages-with-earlier-versions-of-julia/70009)

<div class="topic-metadata">

**Author:** [@Shane\_Kelly](https://discourse.julialang.org/u/Shane_Kelly)\
**Replies:** 1\
**Last updated:** [October 19, 2021, 1:00am UTC](https://discourse.julialang.org/t/using-recently-updated-packages-with-earlier-versions-of-julia/70009 "2021-10-19T01:00:01Z")

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Hello fellow julia users, I’m wondering if someone could help me with the following frustrating problem I have had while installing packages when having slightly outdated versions of Julia. One when trying to install P…

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## [Are packages loaded in an outer module available in inner modules?](https://discourse.julialang.org/t/are-packages-loaded-in-an-outer-module-available-in-inner-modules/70004)

<div class="topic-metadata">

**Author:** [@whatsthecraic](https://discourse.julialang.org/u/whatsthecraic)\
**Replies:** 1\
**Last updated:** [October 18, 2021, 10:39pm UTC](https://discourse.julialang.org/t/are-packages-loaded-in-an-outer-module-available-in-inner-modules/70004 "2021-10-18T22:39:35Z")

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Do packages already loaded need to be reloaded when defining an inner module? For instance, module Outer using Foo using Bar module Inner # can I use Foo and Bar here? end end

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## [How to make division for SparceMatrices?](https://discourse.julialang.org/t/how-to-make-division-for-sparcematrices/70006)

<div class="topic-metadata">

**Author:** [@Amro](https://discourse.julialang.org/u/Amro)\
**Replies:** 2\
**Last updated:** [October 18, 2021, 9:43pm UTC](https://discourse.julialang.org/t/how-to-make-division-for-sparcematrices/70006 "2021-10-18T21:43:03Z")

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In my below MWE, I am trying to use \\ for two Sparce matrices, but I am having an error. Any way to solve it? using SparseArrays; using LinearAlgebra; using .Threads using BenchmarkTools using StaticArrays A = \[1 3 3; 6…

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## [Potential solution to the overflow problem; 64-bit considered harmful, 32- or 21-bit better](https://discourse.julialang.org/t/potential-solution-to-the-overflow-problem-64-bit-considered-harmful-32-or-21-bit-better/69918)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 6\
**Last updated:** [October 18, 2021, 8:28pm UTC](https://discourse.julialang.org/t/potential-solution-to-the-overflow-problem-64-bit-considered-harmful-32-or-21-bit-better/69918 "2021-10-18T20:28:05Z")

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We can implement FastIntegers.jl, faster than the current default Int64 and eliminate overflows from the language by leveraging Julia’s type system, and no hardware support is needed. As a package it of course doesn’t ch…

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## [Turn vector of matrices into 3D array](https://discourse.julialang.org/t/turn-vector-of-matrices-into-3d-array/69777)

<div class="topic-metadata">

**Author:** [@hannesbecher](https://discourse.julialang.org/u/hannesbecher)\
**Replies:** 6\
**Last updated:** [October 18, 2021, 8:14pm UTC](https://discourse.julialang.org/t/turn-vector-of-matrices-into-3d-array/69777 "2021-10-18T20:14:20Z")

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Background: My simulation program returns a 4x4 matrix. Running many replicates using map() or a vector comprehension, I get a long vector of small matrices. Similar to \[rand(4, 4) for \_ in 1:10000\]. Question: Is there …

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## [Unicode support for other fonts in Plots](https://discourse.julialang.org/t/unicode-support-for-other-fonts-in-plots/69971)

<div class="topic-metadata">

**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 6\
**Last updated:** [October 18, 2021, 7:18pm UTC](https://discourse.julialang.org/t/unicode-support-for-other-fonts-in-plots/69971 "2021-10-18T19:18:20Z")

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We can use unicode symbols in plots, like: julia\> plot(rand(10),label="π → 10⁻¹ ×") However, if we change the fonts, most commonly that not this errors: julia\> plot(rand(10),label="π → 10⁻¹ ×",fontfamily="Computer …

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## [Reinforcement Learning Engineers: Please contact me](https://discourse.julialang.org/t/reinforcement-learning-engineers-please-contact-me/69998)

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**Author:** [@SatvikDuddukuru](https://discourse.julialang.org/u/SatvikDuddukuru)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 7:12pm UTC](https://discourse.julialang.org/t/reinforcement-learning-engineers-please-contact-me/69998 "2021-10-18T19:12:36Z")

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I am currently a junior at Liberty High School taking an honors independent study course where I have the opportunity to conduct research on a topic. I have chosen the field of reinforcement learning, and since I have so…

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## [How to open a dll on multiple workers with Distributed.jl](https://discourse.julialang.org/t/how-to-open-a-dll-on-multiple-workers-with-distributed-jl/69997)

<div class="topic-metadata">

**Author:** [@guilhermebodin](https://discourse.julialang.org/u/guilhermebodin)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 6:36pm UTC](https://discourse.julialang.org/t/how-to-open-a-dll-on-multiple-workers-with-distributed-jl/69997 "2021-10-18T18:36:03Z")

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Hi, I am trying to open a dll on multiple workers with the following code using Distributed addprocs(1) nprocs() # 2 @everywhere using Libdl @everywhere p = Libdl.dlopen("libscsdir") @fetchfrom 1 p # Correct @fetchf…

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## [R equivalent Turing model from Statistical Rethkinking (model 8.3)](https://discourse.julialang.org/t/r-equivalent-turing-model-from-statistical-rethkinking-model-8-3/69988)

<div class="topic-metadata">

**Author:** [@amit1](https://discourse.julialang.org/u/amit1)\
**Replies:** 3\
**Last updated:** [October 18, 2021, 6:23pm UTC](https://discourse.julialang.org/t/r-equivalent-turing-model-from-statistical-rethkinking-model-8-3/69988 "2021-10-18T18:23:22Z")

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I am trying to convert the following example from the book Statistical Rethinking book to a Turing model: m8.3 \<- quap( alist( log\_gdp\_std ~ dnorm( mu , sigma ) , mu \<- a\[cid\] + b\[cid\]\*( rugged\_std -…

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## [Missing reference warning for unit Test module in VS code?](https://discourse.julialang.org/t/missing-reference-warning-for-unit-test-module-in-vs-code/69996)

<div class="topic-metadata">

**Author:** [@joseph\_s](https://discourse.julialang.org/u/joseph_s)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 6:19pm UTC](https://discourse.julialang.org/t/missing-reference-warning-for-unit-test-module-in-vs-code/69996 "2021-10-18T18:19:44Z")

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VS Code Julia extension gives Missing reference warning for following using Test @test true I’m using Julia extension v1.4.3. How to get rid of this?

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## [NN Activation Functions with Plotly Dash](https://discourse.julialang.org/t/nn-activation-functions-with-plotly-dash/69992)

<div class="topic-metadata">

**Author:** [@cepel](https://discourse.julialang.org/u/cepel)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 5:44pm UTC](https://discourse.julialang.org/t/nn-activation-functions-with-plotly-dash/69992 "2021-10-18T17:44:35Z")

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Hey everyone! I developed a Dash Julia application for visualizing activation functions in neural networks. You can select multiple activation functions and compare on a line chart. Feel free to review the codes on GitH…

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## [Vigenère cipher](https://discourse.julialang.org/t/vigenere-cipher/69692)

<div class="topic-metadata">

**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 20\
**Last updated:** [October 18, 2021, 5:39pm UTC](https://discourse.julialang.org/t/vigenere-cipher/69692 "2021-10-18T17:39:01Z")

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My daughter is learning about the Vigenère cipher in school and I was helping out (after reading the wiki). They are doing it by hand in school, but it seemed like it might be a good example to start showing her code, si…

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## [Yaxis scale](https://discourse.julialang.org/t/yaxis-scale/69960)

<div class="topic-metadata">

**Author:** [@dbjulia](https://discourse.julialang.org/u/dbjulia)\
**Replies:** 4\
**Last updated:** [October 18, 2021, 5:36pm UTC](https://discourse.julialang.org/t/yaxis-scale/69960 "2021-10-18T17:36:26Z")

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I am trying to plot some data were the y axis of the plot would be in thousands instead of a log scale. I cannot figure out way to do this in Julia. I have tried a few different back ends but to no avail. Code and image …

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## [Rename MWE to S(N)WE](https://discourse.julialang.org/t/rename-mwe-to-s-n-we/69947)

<div class="topic-metadata">

**Author:** [@goerch](https://discourse.julialang.org/u/goerch)\
**Replies:** 6\
**Last updated:** [October 18, 2021, 4:01pm UTC](https://discourse.julialang.org/t/rename-mwe-to-s-n-we/69947 "2021-10-18T16:01:14Z")

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April, 1st I’d propose to rename MWE(minimal working example) to S(N)WE(some (maybe not working) example) to simplify communication with others.

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## [Using NLP and Machine Learning to Link Food and Nutrition Databases](https://discourse.julialang.org/t/using-nlp-and-machine-learning-to-link-food-and-nutrition-databases/69983)

<div class="topic-metadata">

**Author:** [@Nosferican](https://discourse.julialang.org/u/Nosferican)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 3:00pm UTC](https://discourse.julialang.org/t/using-nlp-and-machine-learning-to-link-food-and-nutrition-databases/69983 "2021-10-18T15:00:20Z")

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https://coleridgeinitiative.org/food-for-thought In case anyone is interested in this competition.

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## [Groupby and aggregate a dataframe with custom function that return a vector](https://discourse.julialang.org/t/groupby-and-aggregate-a-dataframe-with-custom-function-that-return-a-vector/69976)

<div class="topic-metadata">

**Author:** [@Pisistrato](https://discourse.julialang.org/u/Pisistrato)\
**Replies:** 8\
**Last updated:** [October 18, 2021, 2:38pm UTC](https://discourse.julialang.org/t/groupby-and-aggregate-a-dataframe-with-custom-function-that-return-a-vector/69976 "2021-10-18T14:38:50Z")

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Hi, It is my understanding that I can have a dataframe column with array/vector. Indeed I can do julia\> df = DataFrame(A = \["M", "F"\], B = \[\[1,4\], \[2,3\]\]) 2×2 DataFrame Row │ A B │ String Array… ───…

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## [Julia add-in for Editplus](https://discourse.julialang.org/t/julia-add-in-for-editplus/69982)

<div class="topic-metadata">

**Author:** [@JaewooJoung](https://discourse.julialang.org/u/JaewooJoung)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 2:29pm UTC](https://discourse.julialang.org/t/julia-add-in-for-editplus/69982 "2021-10-18T14:29:42Z")

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20211018, I made Julia add-in for Editplus: EditPlus - User Files (other files) Those who are using Editplus like me, you can use this file to fire up your coding. Also, you can find it in https://github.com/JaewooJoun…

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## [TypeError: in typeassert in Julia 1.6.3](https://discourse.julialang.org/t/typeerror-in-typeassert-in-julia-1-6-3/69946)

<div class="topic-metadata">

**Author:** [@daneshvar.amrollahi](https://discourse.julialang.org/u/daneshvar.amrollahi)\
**Replies:** 5\
**Last updated:** [October 18, 2021, 2:21pm UTC](https://discourse.julialang.org/t/typeerror-in-typeassert-in-julia-1-6-3/69946 "2021-10-18T14:21:58Z")

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I am new to Julia. I am working on a Julia package which the writer is not available. This is the part of the code where I have a problem with: function find\_partition(model::Model, ms) ps = Dict{Z3Expr,Vector{Int}…

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## [Restructuring code from modules to package](https://discourse.julialang.org/t/restructuring-code-from-modules-to-package/69819)

<div class="topic-metadata">

**Author:** [@Philippe\_Maincon1](https://discourse.julialang.org/u/Philippe_Maincon1)\
**Replies:** 14\
**Last updated:** [October 18, 2021, 1:17pm UTC](https://discourse.julialang.org/t/restructuring-code-from-modules-to-package/69819 "2021-10-18T13:17:51Z")

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I have developed an application that makes use of 20-odd modules. Coming from Matlab, I have ensured that Julia finds my code by adding relevant folders to the LOAD\_PATH. The user uses my application by using relevant …

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## [How to call a Julia variable in memory from the shell?](https://discourse.julialang.org/t/how-to-call-a-julia-variable-in-memory-from-the-shell/69969)

<div class="topic-metadata">

**Author:** [@leon](https://discourse.julialang.org/u/leon)\
**Replies:** 5\
**Last updated:** [October 18, 2021, 1:00pm UTC](https://discourse.julialang.org/t/how-to-call-a-julia-variable-in-memory-from-the-shell/69969 "2021-10-18T13:00:56Z")

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For example, if I have a Julia program test.jl, and I run it in a shell as below: julia test.jl When done, I did not save the variables in the hard disk, but all the variables should be in the memory, am I right? How d…

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## [DiscreteCallbacks for ODEs generated from function closures behaving in a way I can't understand](https://discourse.julialang.org/t/discretecallbacks-for-odes-generated-from-function-closures-behaving-in-a-way-i-cant-understand/69962)

<div class="topic-metadata">

**Author:** [@Dhruva2](https://discourse.julialang.org/u/Dhruva2)\
**Replies:** 4\
**Last updated:** [October 18, 2021, 12:58pm UTC](https://discourse.julialang.org/t/discretecallbacks-for-odes-generated-from-function-closures-behaving-in-a-way-i-cant-understand/69962 "2021-10-18T12:58:15Z")

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Either I’m fundamentally misunderstanding function closures, or DiscreteCallbacks is doing something strange. Either way, input appreciated! I’m using OrdinaryDiffEq and DiffEqCallbacks to simulate an ODE with (multiple…

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## [Seeking Julia package contributor guides](https://discourse.julialang.org/t/seeking-julia-package-contributor-guides/69935)

<div class="topic-metadata">

**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 5\
**Last updated:** [October 18, 2021, 12:36pm UTC](https://discourse.julialang.org/t/seeking-julia-package-contributor-guides/69935 "2021-10-18T12:36:07Z")

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Hey folks, as some of you may or may not know, we are currently in the process of writing and building a contributor home page for the Julia ecosystem (not specifically base Julia), in the hopes of making it really easy …

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## [VSCode does not find julia executable](https://discourse.julialang.org/t/vscode-does-not-find-julia-executable/69972)

<div class="topic-metadata">

**Author:** [@sparrowhawk](https://discourse.julialang.org/u/sparrowhawk)\
**Replies:** 0\
**Last updated:** [October 18, 2021, 12:33pm UTC](https://discourse.julialang.org/t/vscode-does-not-find-julia-executable/69972 "2021-10-18T12:33:26Z")

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I have VSCode very easy to work with, for the most part. However, I’m running into trouble with configuring for a shared CentOS environment where we are developing a package together. I do not have root privileges and w…

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## [Optional or named arguments](https://discourse.julialang.org/t/optional-or-named-arguments/69968)

<div class="topic-metadata">

**Author:** [@whatsthecraic](https://discourse.julialang.org/u/whatsthecraic)\
**Replies:** 1\
**Last updated:** [October 18, 2021, 12:29pm UTC](https://discourse.julialang.org/t/optional-or-named-arguments/69968 "2021-10-18T12:29:12Z")

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base/show.jl defines at line 2218 at least in v1.6 the function function show\_tuple\_as\_call(io::IO, name::Symbol, sig::Type, demangle=false, kwargs=nothing, argnames=nothing, qualified=false) I’m able to invoke it Base.…

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## [Plots.jl: labels overlap if using LaTeXStrings](https://discourse.julialang.org/t/plots-jl-labels-overlap-if-using-latexstrings/69936)

<div class="topic-metadata">

**Author:** [@VivMendes](https://discourse.julialang.org/u/VivMendes)\
**Replies:** 9\
**Last updated:** [October 18, 2021, 11:52am UTC](https://discourse.julialang.org/t/plots-jl-labels-overlap-if-using-latexstrings/69936 "2021-10-18T11:52:02Z")

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Hi, There seems to exist an od behavior of Plots when we use LaTeXStrings to format labels: they overlap. This problem is new because I am revisiting some teaching material, and it did not happen before. I am on a Wind…

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## [Starting point of a nonlinear optimization using Ipopt](https://discourse.julialang.org/t/starting-point-of-a-nonlinear-optimization-using-ipopt/69959)

<div class="topic-metadata">

**Author:** [@FH96](https://discourse.julialang.org/u/FH96)\
**Replies:** 3\
**Last updated:** [October 18, 2021, 11:45am UTC](https://discourse.julialang.org/t/starting-point-of-a-nonlinear-optimization-using-ipopt/69959 "2021-10-18T11:45:27Z")

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If I don’t specify the staring point in a nonlinear optimization using Ipopt ,what does the solver starts with?

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## [Educational document summarising concepts and algorithms in nonlinear programming](https://discourse.julialang.org/t/educational-document-summarising-concepts-and-algorithms-in-nonlinear-programming/69954)

<div class="topic-metadata">

**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 1\
**Last updated:** [October 18, 2021, 11:04am UTC](https://discourse.julialang.org/t/educational-document-summarising-concepts-and-algorithms-in-nonlinear-programming/69954 "2021-10-18T11:04:53Z")

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I adapted part of my PhD thesis intro into an educational writeup covering basic concepts and popular algorithms in nonlinear programming in a hopefully accessible way, targeted at people with some mathematical but not m…

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## [Recursion to iteration](https://discourse.julialang.org/t/recursion-to-iteration/69891)

<div class="topic-metadata">

**Author:** [@goerch](https://discourse.julialang.org/u/goerch)\
**Replies:** 12\
**Last updated:** [October 18, 2021, 10:36am UTC](https://discourse.julialang.org/t/recursion-to-iteration/69891 "2021-10-18T10:36:15Z")

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Hi all, I’m trying to convert some code from recursion to iteration keeping an internal stack. My benchmark is showing no improvement. MWE using BenchmarkTools mutable struct Node{T} value::T left::Union{Nothi…

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