# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1833

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

**Page:** 1834

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## [Problem using Optim.optimize](https://discourse.julialang.org/t/problem-using-optim-optimize/33728)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 36\
**Last updated:** [February 3, 2020, 5:00am UTC](https://discourse.julialang.org/t/problem-using-optim-optimize/33728 "2020-02-03T05:00:41Z")

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Hi guys, I am trying to translate a piece of code from Matlab to Julia, please see following first the original Matlab code: options = optimset('Largescale', 'off', 'MaxFunEvals', 500, 'GradObj','on', 'Display','notify'…

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## [Help to reduce very long compilation time](https://discourse.julialang.org/t/help-to-reduce-very-long-compilation-time/34052)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 10\
**Last updated:** [February 2, 2020, 10:56pm UTC](https://discourse.julialang.org/t/help-to-reduce-very-long-compilation-time/34052 "2020-02-02T22:56:11Z")

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Hi! I am building a package to create text user interfaces in Julia using ncurses: TextUserInterfaces.jl Now, I am facing a very, very slow compilation time. For example, the following code just initialize NCurses, cre…

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## [Interrupting while loops in VSCode](https://discourse.julialang.org/t/interrupting-while-loops-in-vscode/34083)

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**Author:** [@drhouse82](https://discourse.julialang.org/u/drhouse82)\
**Replies:** 2\
**Last updated:** [February 2, 2020, 10:14pm UTC](https://discourse.julialang.org/t/interrupting-while-loops-in-vscode/34083 "2020-02-02T22:14:17Z")

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I’m confused by the behaviour of breaking while loops in VSCode when either using REPL only or running a script from a file. Code: while true println("foo") sleep(1) end If I type this into the VSCode REPL the…

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## [Jump code errors](https://discourse.julialang.org/t/jump-code-errors/34090)

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**Author:** [@bandaya](https://discourse.julialang.org/u/bandaya)\
**Replies:** 2\
**Last updated:** [February 2, 2020, 9:23pm UTC](https://discourse.julialang.org/t/jump-code-errors/34090 "2020-02-02T21:23:52Z")

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Hi, I am new to Julia and I am having problems in running simple examples of Jump. I have given links to two examples below: Manual · MathOptInterface https://nbviewer.jupyter.org/github/JuliaOpt/juliaopt-notebooks/bl…

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## [Access variable values](https://discourse.julialang.org/t/access-variable-values/34070)

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**Author:** [@compleat](https://discourse.julialang.org/u/compleat)\
**Replies:** 6\
**Last updated:** [February 2, 2020, 9:14pm UTC](https://discourse.julialang.org/t/access-variable-values/34070 "2020-02-02T21:14:46Z")

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Pardon my ignorance, but I have a very basic question. Suppose I have a variable and I want to assign the value of that variable to the value of another variable without structurally linking the two variables (i.e., t…

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## [Type hierarchy graphic in docs build](https://discourse.julialang.org/t/type-hierarchy-graphic-in-docs-build/34066)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 7\
**Last updated:** [February 2, 2020, 7:42pm UTC](https://discourse.julialang.org/t/type-hierarchy-graphic-in-docs-build/34066 "2020-02-02T19:42:23Z")

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Is there any pre-existing method for generating a type hierarchy as a graphic image for a Documenter build? My goal is to have the graphic generated automatically.

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## [Spy function for large sparse matrices](https://discourse.julialang.org/t/spy-function-for-large-sparse-matrices/11247)

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**Author:** [@briochemc](https://discourse.julialang.org/u/briochemc)\
**Replies:** 9\
**Last updated:** [February 2, 2020, 7:09pm UTC](https://discourse.julialang.org/t/spy-function-for-large-sparse-matrices/11247 "2020-02-02T19:09:29Z")

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I tried julia\> using Plots julia\> spy(A) for a rather large sparse matrix, and spy just hangs there for too long for it to be useful to me… MATLAB’s spy is quite fast in comparison. I’m guessing Julia’s spy plot is not…

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## [Rolling maxima](https://discourse.julialang.org/t/rolling-maxima/33845)

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**Author:** [@Kruxigt](https://discourse.julialang.org/u/Kruxigt)\
**Replies:** 24\
**Last updated:** [February 2, 2020, 6:08pm UTC](https://discourse.julialang.org/t/rolling-maxima/33845 "2020-02-02T18:08:18Z")

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Hi all fine people here! I am just interested in knowing if anyone here sees any performance improvements in my code. Either algorithmically or Julia specific. The code in question is a function which calculates local …

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## [Comparing Mutable Structs](https://discourse.julialang.org/t/comparing-mutable-structs/10944)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 11\
**Last updated:** [February 2, 2020, 5:59pm UTC](https://discourse.julialang.org/t/comparing-mutable-structs/10944 "2020-02-02T17:59:26Z")

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dear wizards—is this intended behavior? julia\> mutable struct S; x::Int; end#struct## julia\> v= \[ S(1), S(2) \] 2-element Array{S,1}: S(1) S(2) julia\> v==deepcopy(v) ## only when v is mutable false julia\> v==copy(…

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## [Instancing a custom number type and using in arrays](https://discourse.julialang.org/t/instancing-a-custom-number-type-and-using-in-arrays/34071)

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**Author:** [@GregVernon](https://discourse.julialang.org/u/GregVernon)\
**Replies:** 5\
**Last updated:** [February 2, 2020, 5:54pm UTC](https://discourse.julialang.org/t/instancing-a-custom-number-type-and-using-in-arrays/34071 "2020-02-02T17:54:06Z")

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I’m trying to write FEM code for school and I’d like to use custom number types as a means of error-proofing. Essentially, I’d like to have a type difference between element ids, global node ids, local node ids, global …

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## [Custom stateful transducer performance](https://discourse.julialang.org/t/custom-stateful-transducer-performance/34065)

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**Author:** [@Jakub\_Wronowski](https://discourse.julialang.org/u/Jakub_Wronowski)\
**Replies:** 5\
**Last updated:** [February 2, 2020, 3:21pm UTC](https://discourse.julialang.org/t/custom-stateful-transducer-performance/34065 "2020-02-02T15:21:10Z")

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Hi, I am trying to implement a custom stateful transducer, but I am not happy with performance I got. using Transducers using Transducers: Transducer, R\_, next, inner, xform using Transducers: start, complete, wrap, unw…

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## [Export from a submodule](https://discourse.julialang.org/t/export-from-a-submodule/34081)

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**Author:** [@Isaia\_Nisoli](https://discourse.julialang.org/u/Isaia_Nisoli)\
**Replies:** 2\
**Last updated:** [February 2, 2020, 2:39pm UTC](https://discourse.julialang.org/t/export-from-a-submodule/34081 "2020-02-02T14:39:39Z")

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Dear all, I trying to solve this issue, but to no avail. I have the following module structure Module Foo Module Bar export f f(x, y) =x+y end using .Bar end I would like the function f to be visible in the REP…

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## [Exporting (all) names from a module (Clang related)](https://discourse.julialang.org/t/exporting-all-names-from-a-module-clang-related/33828)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 10\
**Last updated:** [February 2, 2020, 2:08pm UTC](https://discourse.julialang.org/t/exporting-all-names-from-a-module-clang-related/33828 "2020-02-02T14:08:29Z")

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I have the following: module CLib using CEnum include("common.jl") include("api.jl") end And naturally I want to automagically export everything that comes in from common and api. Currently if i do using CLib An…

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## [Creating Artifacts.toml for existing tarball](https://discourse.julialang.org/t/creating-artifacts-toml-for-existing-tarball/33365)

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**Author:** [@ssfrr](https://discourse.julialang.org/u/ssfrr)\
**Replies:** 9\
**Last updated:** [February 2, 2020, 1:33pm UTC](https://discourse.julialang.org/t/creating-artifacts-toml-for-existing-tarball/33365 "2020-02-02T13:33:59Z")

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I’m trying to figure out how to create an Artifacts.toml to download some data that my package depends on. I’m creating a setup\_artifacts.jl script to create it. Here’s what I have so far: using Pkg.Artifacts using Pkg…

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## [MKL installation fails on Julia 1.3.1](https://discourse.julialang.org/t/mkl-installation-fails-on-julia-1-3-1/34075)

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**Author:** [@kumarbalachandran](https://discourse.julialang.org/u/kumarbalachandran)\
**Replies:** 1\
**Last updated:** [February 2, 2020, 12:58pm UTC](https://discourse.julialang.org/t/mkl-installation-fails-on-julia-1-3-1/34075 "2020-02-02T12:58:49Z")

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I am trying to install MKL on Windoes 10 and the error log is attached. The installation has succeeded on another machine. add https://github.com/JuliaComputing/MKL.jl #master Cloning git-repo \`https://github.com/Jul…

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## [How to use LBFGS to minimise the cost function for regularised logistic regression](https://discourse.julialang.org/t/how-to-use-lbfgs-to-minimise-the-cost-function-for-regularised-logistic-regression/34058)

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**Author:** [@PyDataBlog](https://discourse.julialang.org/u/PyDataBlog)\
**Replies:** 7\
**Last updated:** [February 2, 2020, 11:12am UTC](https://discourse.julialang.org/t/how-to-use-lbfgs-to-minimise-the-cost-function-for-regularised-logistic-regression/34058 "2020-02-02T11:12:33Z")

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I am currently stuck trying to utilize the Optim package in Julia in an attempt to minimize a cost function. The cost function is the cost function for an L2 regularised logistic regression. It is constructed as follows; …

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## [Julia Roadmap](https://discourse.julialang.org/t/julia-roadmap/33998)

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**Author:** [@digeratus](https://discourse.julialang.org/u/digeratus)\
**Replies:** 20\
**Last updated:** [February 2, 2020, 7:21am UTC](https://discourse.julialang.org/t/julia-roadmap/33998 "2020-02-02T07:21:03Z")

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Other lang communities have public roadmaps e.g. rust, go, ruby, etc I’m wondering if there’s a version for Julia I can take a look. It would help immensely, particularly in terms of transparency, community, etc. Thanks. …

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## [Interact slider, clear cell output question; WebIO problem?](https://discourse.julialang.org/t/interact-slider-clear-cell-output-question-webio-problem/33826)

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**Author:** [@ea42gh](https://discourse.julialang.org/u/ea42gh)\
**Replies:** 5\
**Last updated:** [February 2, 2020, 12:46am UTC](https://discourse.julialang.org/t/interact-slider-clear-cell-output-question-webio-problem/33826 "2020-02-02T00:46:09Z")

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I want to update the output in a jupyter cell based on a slider, but need to clear the cell as I go. Something like: l = collect(1:10) # simplistic: actual code has a list of PrettyTables N\_steps = length(l) step\_ct…

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## [Input parsing for macros without "parantheses"](https://discourse.julialang.org/t/input-parsing-for-macros-without-parantheses/34068)

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**Author:** [@uwechsler](https://discourse.julialang.org/u/uwechsler)\
**Replies:** 2\
**Last updated:** [February 1, 2020, 11:37pm UTC](https://discourse.julialang.org/t/input-parsing-for-macros-without-parantheses/34068 "2020-02-01T23:37:53Z")

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Let’s consider the macro @mymacro which parses some input arguments which are separated by commas as shown below. macro mymacro(expr...) # ... does something with expr return expr end @mymacro(x' = x, x∈X, …

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## [Mathematical Programming Computation: open access publications in optimization](https://discourse.julialang.org/t/mathematical-programming-computation-open-access-publications-in-optimization/34069)

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**Author:** [@dpo](https://discourse.julialang.org/u/dpo)\
**Replies:** 0\
**Last updated:** [February 1, 2020, 11:27pm UTC](https://discourse.julialang.org/t/mathematical-programming-computation-open-access-publications-in-optimization/34069 "2020-02-01T23:27:40Z")

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I hope it’s ok to post this announcement here and that I chose the right category. There was a discussion on Slack/math-optimization recently about publishing optimization research in an open access journal (I can’t fin…

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## [Implement berHu loss in Flux](https://discourse.julialang.org/t/implement-berhu-loss-in-flux/31707)

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**Author:** [@jchen975](https://discourse.julialang.org/u/jchen975)\
**Replies:** 9\
**Last updated:** [February 1, 2020, 9:06pm UTC](https://discourse.julialang.org/t/implement-berhu-loss-in-flux/31707 "2020-02-01T21:06:06Z")

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Hi, I was trying to build this loss function from this paper: I wanted to see if it outperforms squared L2 norm in another regression problem I’m working on. Here is my attempt: function berhu(x, y) x = model…

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## [Broadcasting for a block diagonal matrix](https://discourse.julialang.org/t/broadcasting-for-a-block-diagonal-matrix/34024)

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**Author:** [@teored90](https://discourse.julialang.org/u/teored90)\
**Replies:** 5\
**Last updated:** [February 1, 2020, 7:39pm UTC](https://discourse.julialang.org/t/broadcasting-for-a-block-diagonal-matrix/34024 "2020-02-01T19:39:55Z")

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I would like to implement a more efficient broadcast for basic arithmetic operators for the BlockDiagonal type of BlockDiagonals.jl. At the moment the broadcasting causes many allocations, I suppose because it falls back…

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## [Using reserved words/syntax (try, ?) as macro names](https://discourse.julialang.org/t/using-reserved-words-syntax-try-as-macro-names/34063)

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**Author:** [@kevin.squire](https://discourse.julialang.org/u/kevin.squire)\
**Replies:** 2\
**Last updated:** [February 1, 2020, 4:15pm UTC](https://discourse.julialang.org/t/using-reserved-words-syntax-try-as-macro-names/34063 "2020-02-01T16:15:11Z")

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TL;DR: I’d like to be able to use @try or @? as macro names for try-catch-like syntax in code using Result types. Would this be reasonable to allow? ############ I’ve been exploring ResultTypes.jl as an alternative to…

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## [FOSDEM conference this weekend](https://discourse.julialang.org/t/fosdem-conference-this-weekend/33915)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 2\
**Last updated:** [February 1, 2020, 3:05pm UTC](https://discourse.julialang.org/t/fosdem-conference-this-weekend/33915 "2020-02-01T15:05:30Z")

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Are there any Julians attending FOSDEM in Brussels this weekend? Meet for a beer perhaps?

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## [API for specifying which version of a function to use in a package](https://discourse.julialang.org/t/api-for-specifying-which-version-of-a-function-to-use-in-a-package/34047)

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**Author:** [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Replies:** 5\
**Last updated:** [February 1, 2020, 1:39pm UTC](https://discourse.julialang.org/t/api-for-specifying-which-version-of-a-function-to-use-in-a-package/34047 "2020-02-01T13:39:04Z")

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In IntervalArithmetic.jl we need a way to choose between different versions of a function (e.g. the power function) that have different performance / accuracy tradeoffs. Is there a standard way to have an API for that? …

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## [Error installing ImageView Library](https://discourse.julialang.org/t/error-installing-imageview-library/33976)

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**Author:** [@samantp](https://discourse.julialang.org/u/samantp)\
**Replies:** 14\
**Last updated:** [February 1, 2020, 8:08am UTC](https://discourse.julialang.org/t/error-installing-imageview-library/33976 "2020-02-01T08:08:02Z")

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I work in medical imaging and am therefore trying to install the ImageView Library, but I am getting an error when I build it, as follows (sorry this is a bit lengthy but I have no idea what is important and what is not)…

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## [Resetting a variable to the unsigned state](https://discourse.julialang.org/t/resetting-a-variable-to-the-unsigned-state/34051)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 7\
**Last updated:** [February 1, 2020, 1:31am UTC](https://discourse.julialang.org/t/resetting-a-variable-to-the-unsigned-state/34051 "2020-02-01T01:31:58Z")

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Hi, I’m trying to convert all package global variables to const global, but some of them must be reset at the end (their state is checked at some code point). As an example julia\> a = Array{GMT.GMTcpt,1}(undef,1) 1-el…

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## [MCMC in Economics?](https://discourse.julialang.org/t/mcmc-in-economics/34050)

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**Author:** [@fratrik](https://discourse.julialang.org/u/fratrik)\
**Replies:** 1\
**Last updated:** [January 31, 2020, 11:35pm UTC](https://discourse.julialang.org/t/mcmc-in-economics/34050 "2020-01-31T23:35:04Z")

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Has anyone used one of the MCMC libraries for sampling in macroeconomics? I see that @Tamas\_Papp has developed a library that only depends on the likelihood. However, it looks like Mamba.jl more closely maps onto the so…

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## [Julia alternative for turtle graphics](https://discourse.julialang.org/t/julia-alternative-for-turtle-graphics/31683)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 8\
**Last updated:** [January 31, 2020, 10:56pm UTC](https://discourse.julialang.org/t/julia-alternative-for-turtle-graphics/31683 "2020-01-31T22:56:12Z")

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A while back I made a nice visualization of the Ramanujan tau function using python turtle graphics, which I made for the 100th anniversary of this function. The turtle interface was very nice for making the graphics, wh…

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## [Sample conditional multivariate random variable?](https://discourse.julialang.org/t/sample-conditional-multivariate-random-variable/34035)

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**Author:** [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Replies:** 4\
**Last updated:** [January 31, 2020, 10:40pm UTC](https://discourse.julialang.org/t/sample-conditional-multivariate-random-variable/34035 "2020-01-31T22:40:03Z")

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There’s multivariate random variable, future prices of assets, 5 years from now: X = \[Gold, Silver, SP500\] There’s historical prices for X available for last 50 years. It’s possible to fit historical prices to get mult…

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