# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1436

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

**Page:** 1437

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## [How to fix Error: Method error: objects of type GenericAffExpr{Float64, VariableRef} are not callable](https://discourse.julialang.org/t/how-to-fix-error-method-error-objects-of-type-genericaffexpr-float64-variableref-are-not-callable/58495)

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**Author:** [@GraceMabele](https://discourse.julialang.org/u/GraceMabele)\
**Replies:** 3\
**Last updated:** [April 5, 2021, 12:40pm UTC](https://discourse.julialang.org/t/how-to-fix-error-method-error-objects-of-type-genericaffexpr-float64-variableref-are-not-callable/58495 "2021-04-05T12:40:13Z")

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I would like to create a Taylor expansion of an objective function but I am having trouble as the objective function is a Generic affline expression. Is there a way to use the convert () to convert the form? This is the…

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## [Combining ContinuousCallback and DiscreteCallback in solving ODEProblem (DifferentialEquations)](https://discourse.julialang.org/t/combining-continuouscallback-and-discretecallback-in-solving-odeproblem-differentialequations/58608)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 1\
**Last updated:** [April 5, 2021, 12:15pm UTC](https://discourse.julialang.org/t/combining-continuouscallback-and-discretecallback-in-solving-odeproblem-differentialequations/58608 "2021-04-05T12:15:56Z")

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Is it possible to combine ContinuousCallback and DiscreteCallback while solving ODEProblem? While the former checks if some real quantity attains a zero value, checking a simultaneous satisfaction of some additional logi…

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## [Stray Julia Processes](https://discourse.julialang.org/t/stray-julia-processes/58270)

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**Author:** [@Nicholaswogan](https://discourse.julialang.org/u/Nicholaswogan)\
**Replies:** 9\
**Last updated:** [April 5, 2021, 12:03am UTC](https://discourse.julialang.org/t/stray-julia-processes/58270 "2021-04-05T00:03:55Z")

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I use Julia through Jupyter notebooks on MacOS Catalina (10.15.7). My “activity monitor app” (See screenshot here ) claims I have a TON of Julia stray processes eating up many GB of RAM. Why is this? What am I doing wron…

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## [\[ANN\] GeoStats.jl v0.24](https://discourse.julialang.org/t/ann-geostats-jl-v0-24/58585)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 0\
**Last updated:** [April 5, 2021, 12:52am UTC](https://discourse.julialang.org/t/ann-geostats-jl-v0-24/58585 "2021-04-05T00:52:03Z")

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TL;DR :tada: GeoStats.jl v0.24 comes with full support to general unstructured meshes via the new Meshes.jl project, and provides powerful geospatial queries built with the Query.jl language. Geostatistics on general…

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## [What is the "interface" necessary for DifferentialEquations.jl if your data type does not subclass AbstractArray?](https://discourse.julialang.org/t/what-is-the-interface-necessary-for-differentialequations-jl-if-your-data-type-does-not-subclass-abstractarray/58480)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 5\
**Last updated:** [April 5, 2021, 10:26am UTC](https://discourse.julialang.org/t/what-is-the-interface-necessary-for-differentialequations-jl-if-your-data-type-does-not-subclass-abstractarray/58480 "2021-04-05T10:26:38Z")

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There are a few similar conversation from previous years in this forum (e.g. JuliaDiffEq with custom types - #24 by mzilhao), but I was not able to find official documentation on the topic, and I am uncertain how much of…

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## [Non allocating tuple transformations which include index](https://discourse.julialang.org/t/non-allocating-tuple-transformations-which-include-index/58599)

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**Author:** [@Skoffer](https://discourse.julialang.org/u/Skoffer)\
**Replies:** 4\
**Last updated:** [April 5, 2021, 10:11am UTC](https://discourse.julialang.org/t/non-allocating-tuple-transformations-which-include-index/58599 "2021-04-05T10:11:08Z")

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When one is working with tuples, what is the idiomatic way to do operations, when it is necessary to use element indices? For example, consider that there is a tuple t = (0.1, 0.2, 0.3, 0.4) and it should be transform…

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## [Convert to integer type of minimum required size](https://discourse.julialang.org/t/convert-to-integer-type-of-minimum-required-size/58567)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 6\
**Last updated:** [April 5, 2021, 7:30am UTC](https://discourse.julialang.org/t/convert-to-integer-type-of-minimum-required-size/58567 "2021-04-05T07:30:52Z")

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I thought that this should be a trivial question, but I’m failing to find the answer. How can I convert an arbitrary value for which isinteger(x) is true, into the subtype of Signed or Unsigned with the minimum required …

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## [Creating a simple price-guessing website](https://discourse.julialang.org/t/creating-a-simple-price-guessing-website/58565)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 3\
**Last updated:** [April 5, 2021, 5:40am UTC](https://discourse.julialang.org/t/creating-a-simple-price-guessing-website/58565 "2021-04-05T05:40:54Z")

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I would like to create a (relatively) simple website where users can: Register using Google. Look at random historic 30-day stock charts for tickers on NYSE and Nasdaq. Enter if the stock looked at will RISE or FALL ov…

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## [MCMC Sampler from Mvnorm object](https://discourse.julialang.org/t/mcmc-sampler-from-mvnorm-object/58588)

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**Author:** [@Daniel\_Valdenegro](https://discourse.julialang.org/u/Daniel_Valdenegro)\
**Replies:** 3\
**Last updated:** [April 5, 2021, 1:52am UTC](https://discourse.julialang.org/t/mcmc-sampler-from-mvnorm-object/58588 "2021-04-05T01:52:42Z")

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Hello everyone! I’m running a simple example of MH-MCMC in Julia, and I wonder is there is any function out there that can sample from a defined distribution using MvNorm(). basically, instead of doing: x rand(Mvnorm(…

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## [For loop untill condition == True - Brute Force](https://discourse.julialang.org/t/for-loop-untill-condition-true-brute-force/58583)

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**Author:** [@statspy](https://discourse.julialang.org/u/statspy)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 1:27am UTC](https://discourse.julialang.org/t/for-loop-untill-condition-true-brute-force/58583 "2021-04-05T01:27:31Z")

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I am trying to solve a diophantine equation using a simple for loop to solve this equation: f(x,y) = x^2 + y^3 == 31 So i have defined: X = collect(1:1:10) e Y= collect(1:1:10) and tried: for i in Y for j in X …

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## [Abstract Cell Complex points, edges, faces, etc. for grids](https://discourse.julialang.org/t/abstract-cell-complex-points-edges-faces-etc-for-grids/58460)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 2\
**Last updated:** [April 5, 2021, 1:08am UTC](https://discourse.julialang.org/t/abstract-cell-complex-points-edges-faces-etc-for-grids/58460 "2021-04-05T01:08:33Z")

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Are there any packages that define a representation for n-dimensional grids as 0-cells, 1-cells, … , n-cells, with incidence relations among them? I came across \[1710.07819\] Geometric Computing with Chain Complexes: Des…

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## [POSIX month](https://discourse.julialang.org/t/posix-month/58572)

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**Author:** [@mberlinger3](https://discourse.julialang.org/u/mberlinger3)\
**Replies:** 1\
**Last updated:** [April 4, 2021, 8:44pm UTC](https://discourse.julialang.org/t/posix-month/58572 "2021-04-04T20:44:43Z")

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I’m curious as to why U/u was implement in the dates packages for month and month abbr. respectively. I believe the POSIX standard is B/b according to the Linux manual below: https://pubs.opengroup.org/onlinepubs/007908…

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## [LIKWID profiler](https://discourse.julialang.org/t/likwid-profiler/58543)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 1\
**Last updated:** [April 4, 2021, 8:15pm UTC](https://discourse.julialang.org/t/likwid-profiler/58543 "2021-04-04T20:15:29Z")

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Definitely worth reading if you are interested in finding detail on the CPU or GPU system you are working with. If this belongs in Off Topic I will happily move it.

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## [Error in plotting the graph](https://discourse.julialang.org/t/error-in-plotting-the-graph/58548)

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**Author:** [@Manisha\_07](https://discourse.julialang.org/u/Manisha_07)\
**Replies:** 3\
**Last updated:** [April 4, 2021, 8:11pm UTC](https://discourse.julialang.org/t/error-in-plotting-the-graph/58548 "2021-04-04T20:11:45Z")

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Hello I am trying to excecute the program but facing the issue only when i am trying to plot the fucntion, //my program n\_samples = 15 lower\_bound = 0 upper\_bound = 14/15 x = sample(n\_samples, lower\_bound, upper\_bo…

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## [Slider or drop menus in Makie](https://discourse.julialang.org/t/slider-or-drop-menus-in-makie/58560)

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**Author:** [@lazarusA](https://discourse.julialang.org/u/lazarusA)\
**Replies:** 6\
**Last updated:** [April 4, 2021, 8:03pm UTC](https://discourse.julialang.org/t/slider-or-drop-menus-in-makie/58560 "2021-04-04T20:03:03Z")

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Hello, probably the following is too much to ask, but could someone please take a look at this and see if it is possible to add two drop menus for l and m, or two sliders, either will be fine. I tried to follow the docu…

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## [SymPy function with 2 variables](https://discourse.julialang.org/t/sympy-function-with-2-variables/58538)

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**Author:** [@statspy](https://discourse.julialang.org/u/statspy)\
**Replies:** 4\
**Last updated:** [April 4, 2021, 7:02pm UTC](https://discourse.julialang.org/t/sympy-function-with-2-variables/58538 "2021-04-04T19:02:22Z")

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i am trying: julia\> a=Equality(x^2 + y^3, 31) i would like to get x=2 and y=3. How ca i do it? I tried solve(a,\[x,y\]) and solve(a) but i am getting: (-sqrt(31 - y^3), y) (sqrt(31 - y^3), y)

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## [Simplex transforms in Bijectors.jl (sorry)](https://discourse.julialang.org/t/simplex-transforms-in-bijectors-jl-sorry/56372)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 9\
**Last updated:** [April 4, 2021, 6:57pm UTC](https://discourse.julialang.org/t/simplex-transforms-in-bijectors-jl-sorry/56372 "2021-04-04T18:57:17Z")

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I’d like to understand the ideas behind the way Bijectors handles simplices. First, something I think I understand, for comparison: TransformVariables julia\> using TransformVariables julia\> t = UnitSimplex(4) UnitSimp…

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## [Best way to deregister cam2d selection zoom? GLMakie - solved](https://discourse.julialang.org/t/best-way-to-deregister-cam2d-selection-zoom-glmakie-solved/58549)

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**Author:** [@kool7d](https://discourse.julialang.org/u/kool7d)\
**Replies:** 0\
**Last updated:** [April 4, 2021, 7:06am UTC](https://discourse.julialang.org/t/best-way-to-deregister-cam2d-selection-zoom-glmakie-solved/58549 "2021-04-04T07:06:01Z")

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how do I deregister the rectangle selection zoom for cam2d? xzoomlock and yzoomlock don’t work. I can stop it from zooming if I do off(fm1.scene.events.mousedrag.listeners\[1\].mouseevent, fm1.scene.events.mousedrag.l…

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## [Executing Julia on iOS?](https://discourse.julialang.org/t/executing-julia-on-ios/58558)

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**Author:** [@drjoke](https://discourse.julialang.org/u/drjoke)\
**Replies:** 2\
**Last updated:** [April 4, 2021, 3:13pm UTC](https://discourse.julialang.org/t/executing-julia-on-ios/58558 "2021-04-04T15:13:26Z")

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I am not asking about programming Julia on iOS, but I am asking about executing Julia programs on iOS. I have written several Julia programs that retrieve online information, do calculations and produce reports. The pro…

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## [BrowseTables configure details of table](https://discourse.julialang.org/t/browsetables-configure-details-of-table/58486)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 9\
**Last updated:** [April 4, 2021, 2:10pm UTC](https://discourse.julialang.org/t/browsetables-configure-details-of-table/58486 "2021-04-04T14:10:05Z")

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I have a table in a Pluto notebook that I would prefer to have as an HTML object, so that I can smoothly integrate it with test in markdown. BrowseTables.jl does exacly that - defining an HTMLTable and using the $variabl…

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## [Julia 1.6 stacktrace displayed weirdly in iTerm2 with dark color scheme and transparent background](https://discourse.julialang.org/t/julia-1-6-stacktrace-displayed-weirdly-in-iterm2-with-dark-color-scheme-and-transparent-background/58554)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 3\
**Last updated:** [April 4, 2021, 12:12pm UTC](https://discourse.julialang.org/t/julia-1-6-stacktrace-displayed-weirdly-in-iterm2-with-dark-color-scheme-and-transparent-background/58554 "2021-04-04T12:12:08Z")

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Please see the screenshots. I can hardly see some parts of each stacktrace \[1\], \[2\], \[3\], etc. How can I fix it? Julia versions before 1.6 have no problem.

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## [Calling Julia from MATLAB](https://discourse.julialang.org/t/calling-julia-from-matlab/51542)

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**Author:** [@Vangelis](https://discourse.julialang.org/u/Vangelis)\
**Replies:** 19\
**Last updated:** [April 4, 2021, 1:30am UTC](https://discourse.julialang.org/t/calling-julia-from-matlab/51542 "2021-04-04T01:30:28Z")

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Hello everyone, I am trying to call a Julia algorithm from MATLAB. Looking at https://github.com/juliamatlab/ I found the: mexjulia jlcall I tried both and, after making some corrections (because are meant for Julia…

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## [How to use a numerical type parameters in declaration](https://discourse.julialang.org/t/how-to-use-a-numerical-type-parameters-in-declaration/58535)

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**Author:** [@jsjie](https://discourse.julialang.org/u/jsjie)\
**Replies:** 5\
**Last updated:** [April 4, 2021, 1:16am UTC](https://discourse.julialang.org/t/how-to-use-a-numerical-type-parameters-in-declaration/58535 "2021-04-04T01:16:43Z")

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I’m trying to do something about physics, and I’ve written a struct like struct System charge\_density end now there is something called “spin” that may, but not must be considered in physics, and the data structure…

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## [Type Stability: Collections of Abstract Types](https://discourse.julialang.org/t/type-stability-collections-of-abstract-types/58525)

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**Author:** [@RobertGregg](https://discourse.julialang.org/u/RobertGregg)\
**Replies:** 5\
**Last updated:** [April 4, 2021, 1:07am UTC](https://discourse.julialang.org/t/type-stability-collections-of-abstract-types/58525 "2021-04-04T01:07:20Z")

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I’ve been struggling with vectors of abstract types and making them type stable. Here is an example: abstract type Home{T\<:String} end mutable struct Condo{T} \<: Home{T} color::T end struct Apartment{T} \<: Home{T}…

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## [Using RegionTrees adaptivesampling! with MappedArrays](https://discourse.julialang.org/t/using-regiontrees-adaptivesampling-with-mappedarrays/58477)

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**Author:** [@Crghilardi](https://discourse.julialang.org/u/Crghilardi)\
**Replies:** 0\
**Last updated:** [April 3, 2021, 1:32am UTC](https://discourse.julialang.org/t/using-regiontrees-adaptivesampling-with-mappedarrays/58477 "2021-04-03T01:32:40Z")

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I’m playing around with RegionTrees and am trying to write a refinery that makes an octree given a bunch of points. The twist being my points are in a MappedArray. I can populate an initial Cell with the MappedArray data…

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## [Displaying Plots and images from REPL](https://discourse.julialang.org/t/displaying-plots-and-images-from-repl/58500)

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**Author:** [@LarryJW](https://discourse.julialang.org/u/LarryJW)\
**Replies:** 3\
**Last updated:** [April 3, 2021, 10:26pm UTC](https://discourse.julialang.org/t/displaying-plots-and-images-from-repl/58500 "2021-04-03T22:26:12Z")

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New to Julia. I want to use Julia using only a simple text editor and the Julia 1.6.0 REPL. My initial programming goal is to replicate in Julia some code I’d written in Mathematica (Wolfram Language) to display a graph,…

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## [How to write type-stable dataflow graphs](https://discourse.julialang.org/t/how-to-write-type-stable-dataflow-graphs/57373)

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**Author:** [@marty0801](https://discourse.julialang.org/u/marty0801)\
**Replies:** 14\
**Last updated:** [April 3, 2021, 11:37pm UTC](https://discourse.julialang.org/t/how-to-write-type-stable-dataflow-graphs/57373 "2021-04-03T23:37:34Z")

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I’m trying to implement a dataflow graph for basic arithmetic and encountering type instability for all but trivially simple graphs. How to rewrite this in a type-stable way? module Inst # for "type-instability" import…

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## [Time to first plot clarification](https://discourse.julialang.org/t/time-to-first-plot-clarification/58534)

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**Author:** [@Lyngbakr](https://discourse.julialang.org/u/Lyngbakr)\
**Replies:** 1\
**Last updated:** [April 3, 2021, 11:36pm UTC](https://discourse.julialang.org/t/time-to-first-plot-clarification/58534 "2021-04-03T23:36:33Z")

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I’m embarrassed to ask given that the phrase is used so often, but I was hoping someone could clarify the phrase time to first plot for me. My understanding is that the first time that a script is run that it can take a …

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## [Trivial question about workers on a cluster](https://discourse.julialang.org/t/trivial-question-about-workers-on-a-cluster/58517)

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**Author:** [@Frisus95](https://discourse.julialang.org/u/Frisus95)\
**Replies:** 1\
**Last updated:** [April 3, 2021, 10:40pm UTC](https://discourse.julialang.org/t/trivial-question-about-workers-on-a-cluster/58517 "2021-04-03T22:40:21Z")

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Good day everyone! As the title suggests, I have a (probably trivial) question about how to run a parallel computation on multiple nodes in a cluster. My code calls an external library, written in C, and then paralleli…

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## [Plotting a R→C function](https://discourse.julialang.org/t/plotting-a-r-c-function/57916)

<div class="topic-metadata">

**Author:** [@owiecc](https://discourse.julialang.org/u/owiecc)\
**Replies:** 3\
**Last updated:** [April 3, 2021, 10:35pm UTC](https://discourse.julialang.org/t/plotting-a-r-c-function/57916 "2021-04-03T22:35:56Z")

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Is there a better way to plot a function that maps from real to complex numbers? f(x) = 2x+x^2\*1im plot(real∘f, imag∘f, 0, 2π, legend=false, xlabel="Re", ylabel="Im") When I plot an Array{Complex{Float64},1} I get the …

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