# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1989

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

**Page:** 1990

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## [Animation with timeline and play/pause](https://discourse.julialang.org/t/animation-with-timeline-and-play-pause/24575)

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**Author:** [@Seanny123](https://discourse.julialang.org/u/Seanny123)\
**Replies:** 2\
**Last updated:** [May 25, 2019, 6:30am UTC](https://discourse.julialang.org/t/animation-with-timeline-and-play-pause/24575 "2019-05-25T06:30:21Z")

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Often, I want to watch a visual system over time with the same basic controls as a video. Specifically: Play/Pause Drag around on a timeline Encoding a basic SVG animation is often overkill, so in Python, I awkwardly …

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## [Randomly generate a GPS location in WGS 84 format from China?](https://discourse.julialang.org/t/randomly-generate-a-gps-location-in-wgs-84-format-from-china/24579)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 3\
**Last updated:** [May 24, 2019, 10:02pm UTC](https://discourse.julialang.org/t/randomly-generate-a-gps-location-in-wgs-84-format-from-china/24579 "2019-05-24T22:02:50Z")

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Hi, this is not exactly a Julia question I guess. But I really like this forum. So I post it here. I was wondering, how to randomly generate a GPS location from China in WGS 84 format? I guess we will need to find the ra…

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## [Unexpected behavior with multiple processors and @everywhere in for loop](https://discourse.julialang.org/t/unexpected-behavior-with-multiple-processors-and-everywhere-in-for-loop/24589)

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**Author:** [@omalled](https://discourse.julialang.org/u/omalled)\
**Replies:** 0\
**Last updated:** [May 24, 2019, 9:50pm UTC](https://discourse.julialang.org/t/unexpected-behavior-with-multiple-processors-and-everywhere-in-for-loop/24589 "2019-05-24T21:50:04Z")

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I’m running into an issue that I can’t wrap my head around. Here’s a MWE reduced from a more complex code: i = 0 for j = 1:2 global i i = j @show :before, myid(), i @everywhere i = remotecall\_fetch(()-\>i, 1) @show …

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## [1.1.1 - sporadic "\<varname\>" not defined](https://discourse.julialang.org/t/1-1-1-sporadic-varname-not-defined/24580)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 3\
**Last updated:** [May 24, 2019, 6:41pm UTC](https://discourse.julialang.org/t/1-1-1-sporadic-varname-not-defined/24580 "2019-05-24T18:41:01Z")

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I’m getting a sporadic \<varname\> not defined error on 1.1.1 for one of my workspace variables. The next time I run the command it typically executes as expected. I recall there being an earlier sporadic issue where ther…

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## [Nested QuadGK: Long compilation time gets short when plotting the argument beforehand, but not when calling it](https://discourse.julialang.org/t/nested-quadgk-long-compilation-time-gets-short-when-plotting-the-argument-beforehand-but-not-when-calling-it/24519)

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**Author:** [@alpharho](https://discourse.julialang.org/u/alpharho)\
**Replies:** 2\
**Last updated:** [May 24, 2019, 3:34pm UTC](https://discourse.julialang.org/t/nested-quadgk-long-compilation-time-gets-short-when-plotting-the-argument-beforehand-but-not-when-calling-it/24519 "2019-05-24T15:34:57Z")

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Hey everyone, I stumbled upon a weird behaviour of compilation time. I have the following function definitions: using QuadGK …

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## [Random numbers, why is it necessary to multiply by rand()](https://discourse.julialang.org/t/random-numbers-why-is-it-necessary-to-multiply-by-rand/24539)

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**Author:** [@isamuelsson](https://discourse.julialang.org/u/isamuelsson)\
**Replies:** 6\
**Last updated:** [May 24, 2019, 3:01pm UTC](https://discourse.julialang.org/t/random-numbers-why-is-it-necessary-to-multiply-by-rand/24539 "2019-05-24T15:01:31Z")

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Hi I am working on the pi example in JuliaBox. When I am generating random numbers the only way I do not get 0 as the value of pi is if I multiply by rand() (as it did in the solution to the exercise). It looks like mult…

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## [Avoiding Memory leaks using CuArrays](https://discourse.julialang.org/t/avoiding-memory-leaks-using-cuarrays/24325)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 3\
**Last updated:** [May 24, 2019, 2:51pm UTC](https://discourse.julialang.org/t/avoiding-memory-leaks-using-cuarrays/24325 "2019-05-24T14:51:53Z")

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Hello, I have read that there is no garbage collection in GPUs. I have an algorithm where I use an Array{Array{CuArrays{Float32,1},1}} as a buffer. From that I sample a batch that I transform in a NTuple{CuArrays, N} to…

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## [How to find min/max or Q1/median/Q3 in Julia](https://discourse.julialang.org/t/how-to-find-min-max-or-q1-median-q3-in-julia/24573)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 2\
**Last updated:** [May 24, 2019, 2:41pm UTC](https://discourse.julialang.org/t/how-to-find-min-max-or-q1-median-q3-in-julia/24573 "2019-05-24T14:41:08Z")

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Dear all, I have a dataframe and I can use describe to have an initial hint of the data. But to have more control, I would like to find these values one column at the time. So I can find the average of one column with m…

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## [PackageCompiler error](https://discourse.julialang.org/t/packagecompiler-error/24570)

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**Author:** [@Maxim\_Chase](https://discourse.julialang.org/u/Maxim_Chase)\
**Replies:** 2\
**Last updated:** [May 24, 2019, 2:35pm UTC](https://discourse.julialang.org/t/packagecompiler-error/24570 "2019-05-24T14:35:02Z")

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Hi guys! I’m a newbie in Julia, and I have a question. While building PackageCompiler I received this error Error building PackageCompiler LoadError: Package candidate for gcc not found. Any suggestions? What I actually …

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## [1.1.1 upgrade, JLD2, and a cascade of errors](https://discourse.julialang.org/t/1-1-1-upgrade-jld2-and-a-cascade-of-errors/24540)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 3\
**Last updated:** [May 24, 2019, 2:23pm UTC](https://discourse.julialang.org/t/1-1-1-upgrade-jld2-and-a-cascade-of-errors/24540 "2019-05-24T14:23:32Z")

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I installed 1.1.1 for use in Juno and updated the Atom packages, then tried to bring my packages in. When I added JLD2.jl, after it updated WeakRefStrings to 0.6.1, I got an ArgumentError: Package Reexport not found in c…

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## [Is it possible to create a new constructor in JLCXX\_MODULE?](https://discourse.julialang.org/t/is-it-possible-to-create-a-new-constructor-in-jlcxx-module/24455)

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**Author:** [@alligatorme](https://discourse.julialang.org/u/alligatorme)\
**Replies:** 1\
**Last updated:** [May 24, 2019, 2:16pm UTC](https://discourse.julialang.org/t/is-it-possible-to-create-a-new-constructor-in-jlcxx-module/24455 "2019-05-24T14:16:47Z")

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JLCXX\_MODULE define\_julia\_module(jlcxx::Module& types) { types.add\_type\<World\>("World") .constructor\<const std::string&\>() .constructor\<int\_t\>(false) // no finalizer .method("set", &World::set) .method…

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## [Function getindex does not accept keyword arguments](https://discourse.julialang.org/t/function-getindex-does-not-accept-keyword-arguments/24564)

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**Author:** [@Octarosu](https://discourse.julialang.org/u/Octarosu)\
**Replies:** 1\
**Last updated:** [May 24, 2019, 1:21pm UTC](https://discourse.julialang.org/t/function-getindex-does-not-accept-keyword-arguments/24564 "2019-05-24T13:21:05Z")

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Hello, I implemented this function for economic dispatch function solve\_ed(g\_max, g\_min, c\_g, c\_w, d, w\_f) #Define the economic dispatch (ED) model ed=Model() # Define decision variables @defVar(ed, 0 \<= g\[i=1:2…

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## [Save variable to variable name](https://discourse.julialang.org/t/save-variable-to-variable-name/24565)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 1\
**Last updated:** [May 24, 2019, 1:15pm UTC](https://discourse.julialang.org/t/save-variable-to-variable-name/24565 "2019-05-24T13:15:28Z")

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Giving up… I have a bunch of JulaiDB tables and I want to save them. To avoid zipping through a list of their variables and an irritatingly similar list of the variables’ names, I’d like to solve this with metaprogrammi…

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## [How to enable the scroll down slides in Jupyter Ijulia](https://discourse.julialang.org/t/how-to-enable-the-scroll-down-slides-in-jupyter-ijulia/24567)

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**Author:** [@Santiago\_Cuervo](https://discourse.julialang.org/u/Santiago_Cuervo)\
**Replies:** 0\
**Last updated:** [May 24, 2019, 1:12pm UTC](https://discourse.julialang.org/t/how-to-enable-the-scroll-down-slides-in-jupyter-ijulia/24567 "2019-05-24T13:12:27Z")

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How to enable the scroll down slides in Jupyter Ijulia 1.1 ? When the notebook is downloaded as reveal or slides is not enable the scroll down feature, consequently when presenting large code blocks are not fully displa…

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## [DynamicHMC: multivariate normal loglikelihood?](https://discourse.julialang.org/t/dynamichmc-multivariate-normal-loglikelihood/24505)

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**Author:** [@mcreel](https://discourse.julialang.org/u/mcreel)\
**Replies:** 10\
**Last updated:** [May 24, 2019, 11:30am UTC](https://discourse.julialang.org/t/dynamichmc-multivariate-normal-loglikelihood/24505 "2019-05-24T11:30:34Z")

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I have a simple example working with a univariate normal loglikelihood, but I am having trouble extending it to multivariate normal. I am implementing simulated moments, with the asymptotic Gaussian distribution used to …

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## [Deepcopy command during debugging leads to error message](https://discourse.julialang.org/t/deepcopy-command-during-debugging-leads-to-error-message/24561)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 1\
**Last updated:** [May 24, 2019, 11:28am UTC](https://discourse.julialang.org/t/deepcopy-command-during-debugging-leads-to-error-message/24561 "2019-05-24T11:28:39Z")

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Hello, I got an error message during debugging when I step over a command, which makes a copy of an object of a mutable struct with the function deepcopy. ERROR: MethodError: no method matching ccall\_jl\_set\_nth\_field\_6…

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## [Equality Constraint format in NLopt](https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491)

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**Author:** [@CPPhysics](https://discourse.julialang.org/u/CPPhysics)\
**Replies:** 5\
**Last updated:** [May 24, 2019, 11:21am UTC](https://discourse.julialang.org/t/equality-constraint-format-in-nlopt/24491 "2019-05-24T11:21:58Z")

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I have a Nonlinear optimization problem with equality constraints which I have been implementing as lagrange multiplier constraints, but I’d like to see if NLopt can handle them better. One of my constraints is that the…

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## [Type inference from list of functions](https://discourse.julialang.org/t/type-inference-from-list-of-functions/24538)

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**Author:** [@misha\_mikhasenko](https://discourse.julialang.org/u/misha_mikhasenko)\
**Replies:** 11\
**Last updated:** [May 24, 2019, 10:59am UTC](https://discourse.julialang.org/t/type-inference-from-list-of-functions/24538 "2019-05-24T10:59:03Z")

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I was surprised that type inference does not work in this case for i=1:3 @eval $(Symbol("f"\*string(i)))(x) = x^$(i)+$(i) end # @code\_warntype f1(1.1) # it is Float64, fine! # function test(i) list\_of\_functions …

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## [Interesting micro-benchmark](https://discourse.julialang.org/t/interesting-micro-benchmark/24529)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 8\
**Last updated:** [May 24, 2019, 10:52am UTC](https://discourse.julialang.org/t/interesting-micro-benchmark/24529 "2019-05-24T10:52:59Z")

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The data set i’m processing is organized in chunks, and each chunk is variable length, and i have to filter over all the chunks and create a set of data for several categories. i noticed that my program was starting to …

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## [Problem Installing ZMQ as part of IJulia](https://discourse.julialang.org/t/problem-installing-zmq-as-part-of-ijulia/24560)

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**Author:** [@JP\_91](https://discourse.julialang.org/u/JP_91)\
**Replies:** 0\
**Last updated:** [May 24, 2019, 10:38am UTC](https://discourse.julialang.org/t/problem-installing-zmq-as-part-of-ijulia/24560 "2019-05-24T10:38:05Z")

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Hi. I am having problems installing ZMQ when I try to install IJulia. I am working on windows 7 with julia 1.1.0. I get the following error: Dropbox - Error\_IJulia.png - Simplify your life. In advance, thank you for your…

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## [Comunication with instrument](https://discourse.julialang.org/t/comunication-with-instrument/24544)

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**Author:** [@rjsharp](https://discourse.julialang.org/u/rjsharp)\
**Replies:** 4\
**Last updated:** [May 24, 2019, 10:37am UTC](https://discourse.julialang.org/t/comunication-with-instrument/24544 "2019-05-24T10:37:57Z")

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Hi everyone, I started to using Julia a couple of weeks ago for a small project. My goal is to build a HPLC system, and not only being able to work the data acquired but also to control some of the equipment. I am faci…

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## [Macro: escaping, interpolation, scope etc](https://discourse.julialang.org/t/macro-escaping-interpolation-scope-etc/24408)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 7\
**Last updated:** [May 24, 2019, 10:02am UTC](https://discourse.julialang.org/t/macro-escaping-interpolation-scope-etc/24408 "2019-05-24T10:02:26Z")

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I would like to achieve something along the following lines: when I write @all(A), it should replace it with A\[ix,iy,iz\] in the caller’s scope (ix, iy and iz are defined in the caller’s scope). So, I wrote the followin…

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## [Local/new package requires project to be activated](https://discourse.julialang.org/t/local-new-package-requires-project-to-be-activated/24467)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 4\
**Last updated:** [May 24, 2019, 9:05am UTC](https://discourse.julialang.org/t/local-new-package-requires-project-to-be-activated/24467 "2019-05-24T09:05:35Z")

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Hi, I think I’m doing something wrong when creating packages. When I try to load a package I have created its dependencies are not found unless I also activate the project. Example: (v1.1) pkg\> generate Test Generatin…

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## [Using PackageCompiler to create a custom system image](https://discourse.julialang.org/t/using-packagecompiler-to-create-a-custom-system-image/24528)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 11\
**Last updated:** [May 24, 2019, 2:20am UTC](https://discourse.julialang.org/t/using-packagecompiler-to-create-a-custom-system-image/24528 "2019-05-24T02:20:14Z")

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Hi guys, I need help to create a custom system image Using PackageCompiler. I need to build a system image with a package bundled. The idea is to send this system image to another person that will be able to use my pack…

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## [Access variable inside of a funciton from another function](https://discourse.julialang.org/t/access-variable-inside-of-a-funciton-from-another-function/24268)

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**Author:** [@orange\_si](https://discourse.julialang.org/u/orange_si)\
**Replies:** 10\
**Last updated:** [May 24, 2019, 1:15am UTC](https://discourse.julialang.org/t/access-variable-inside-of-a-funciton-from-another-function/24268 "2019-05-24T01:15:40Z")

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hello, everyone, I have a question about how to access local variable of a funciton in another funciton, my code is like this: function FA() name = "world" return "hello" end function FB(f::Function) printl…

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## [Shallow water equations with DifferentialEquations.jl](https://discourse.julialang.org/t/shallow-water-equations-with-differentialequations-jl/2691)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 22\
**Last updated:** [May 24, 2019, 12:31am UTC](https://discourse.julialang.org/t/shallow-water-equations-with-differentialequations-jl/2691 "2019-05-24T00:31:41Z")

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I am really interested in using the DifferentialEquations.jl framework to solve the shallow water equations over a 2D domain efficiently instead of coding my own solution. How would you formulate the problem in Differen…

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## [Macro to create a struct with variable number of fields?](https://discourse.julialang.org/t/macro-to-create-a-struct-with-variable-number-of-fields/24486)

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**Author:** [@FrankCimballi](https://discourse.julialang.org/u/FrankCimballi)\
**Replies:** 2\
**Last updated:** [May 23, 2019, 10:27pm UTC](https://discourse.julialang.org/t/macro-to-create-a-struct-with-variable-number-of-fields/24486 "2019-05-23T22:27:09Z")

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My first failed attempt at a macro! I want to be able to generate a struct definition by passing a classname and fields. May code should look something like this? macro create\_class(classname, fields) quote …

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## [Some project already done in Julia about image processing](https://discourse.julialang.org/t/some-project-already-done-in-julia-about-image-processing/24533)

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**Author:** [@GERSON\_EZEQUIEL\_HERN](https://discourse.julialang.org/u/GERSON_EZEQUIEL_HERN)\
**Replies:** 1\
**Last updated:** [May 23, 2019, 8:38pm UTC](https://discourse.julialang.org/t/some-project-already-done-in-julia-about-image-processing/24533 "2019-05-23T20:38:37Z")

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someone could help me or could you provide me with a project that has to do with recognition of patterns in images working in Julia. Help me…!!

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## [CUDAnative tests failing on Windows 10](https://discourse.julialang.org/t/cudanative-tests-failing-on-windows-10/24465)

<div class="topic-metadata">

**Author:** [@manderson](https://discourse.julialang.org/u/manderson)\
**Replies:** 5\
**Last updated:** [May 23, 2019, 7:57pm UTC](https://discourse.julialang.org/t/cudanative-tests-failing-on-windows-10/24465 "2019-05-23T19:57:07Z")

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Hello, I’m having some platform dependent problems getting CUDAnative working all the way. On my Ubuntu system I am having no problems, but on my windows machines the tests for the package are failing and I cannot make …

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## [Ternary operator ?: confused with quoting](https://discourse.julialang.org/t/ternary-operator-confused-with-quoting/24536)

<div class="topic-metadata">

**Author:** [@isamuelsson](https://discourse.julialang.org/u/isamuelsson)\
**Replies:** 2\
**Last updated:** [May 23, 2019, 7:30pm UTC](https://discourse.julialang.org/t/ternary-operator-confused-with-quoting/24536 "2019-05-23T19:30:08Z")

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Hi I am doing the pi exercise in JuliaBox and would like to know how I could use the ternary operator ( a ? b : c ) correctly. Any suggestions? function calculate\_pi(N,r) Acircle = 0 Asquare = 0 for x in 1:N …

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