# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1825

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

**Page:** 1826

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## [Why Atom try to reinstall Matplotlib using Conda so frequently?](https://discourse.julialang.org/t/why-atom-try-to-reinstall-matplotlib-using-conda-so-frequently/34576)

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**Author:** [@josimar](https://discourse.julialang.org/u/josimar)\
**Replies:** 0\
**Last updated:** [February 13, 2020, 2:33pm UTC](https://discourse.julialang.org/t/why-atom-try-to-reinstall-matplotlib-using-conda-so-frequently/34576 "2020-02-13T14:33:17Z")

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It often happens that Atom tries to reinstall matplotlib using Conda. However, this is already installed and I don’t understand why it gets stuck on this. Below I copy the exact code and message that I get. Note: this …

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## [Making a surface from scattered data](https://discourse.julialang.org/t/making-a-surface-from-scattered-data/27622)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 4\
**Last updated:** [February 13, 2020, 2:29pm UTC](https://discourse.julialang.org/t/making-a-surface-from-scattered-data/27622 "2020-02-13T14:29:12Z")

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I would to transform scattered data into a surface. Google told me that is I could do it in Matlab\[1,2\] or Python \[3\] using Delaunay triangulation. But I cannot find a similar example in Julia with VoronoiDelaunay.jl an…

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## [I can load a package in REPL but not in a .jl script on Juno](https://discourse.julialang.org/t/i-can-load-a-package-in-repl-but-not-in-a-jl-script-on-juno/34571)

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**Author:** [@samantp](https://discourse.julialang.org/u/samantp)\
**Replies:** 1\
**Last updated:** [February 13, 2020, 1:25pm UTC](https://discourse.julialang.org/t/i-can-load-a-package-in-repl-but-not-in-a-jl-script-on-juno/34571 "2020-02-13T13:25:01Z")

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I’m having a bit of a bizarre error. I am trying to write a script in which I use the PyPlot package. if I type using PyPlot into the REPL, it runs without a problem as far as I can tell. However, when I have the exact …

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## [Gradient of jacobian in Flux v0.10 (zygote)](https://discourse.julialang.org/t/gradient-of-jacobian-in-flux-v0-10-zygote/34572)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 0\
**Last updated:** [February 13, 2020, 1:22pm UTC](https://discourse.julialang.org/t/gradient-of-jacobian-in-flux-v0-10-zygote/34572 "2020-02-13T13:22:31Z")

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Hi all, in our project on modelling probability distributions we need to calculate a gradient of a function, which involves jacobian of the model. Zygote (Flux) crashes with the output that mutating arrays are not suppo…

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## [\[ANN\] PeaceFounder's project - PeaceVote.jl](https://discourse.julialang.org/t/ann-peacefounders-project-peacevote-jl/34389)

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**Author:** [@Janis\_Erdmanis](https://discourse.julialang.org/u/Janis_Erdmanis)\
**Replies:** 4\
**Last updated:** [February 13, 2020, 11:40am UTC](https://discourse.julialang.org/t/ann-peacefounders-project-peacevote-jl/34389 "2020-02-13T11:40:05Z")

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Hello, everyone :slight\_smile: I am announcing three packages PeaceVote, SynchronicBallot, PeaceFounder as well as a prototype community https://github.com/PeaceFounder/Community.jl for transparent, secure and anonymous…

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## [ERROR: The following package names could not be resolved - JWAS to perform GWAS](https://discourse.julialang.org/t/error-the-following-package-names-could-not-be-resolved-jwas-to-perform-gwas/34519)

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**Author:** [@ayelna](https://discourse.julialang.org/u/ayelna)\
**Replies:** 7\
**Last updated:** [February 13, 2020, 9:31am UTC](https://discourse.julialang.org/t/error-the-following-package-names-could-not-be-resolved-jwas-to-perform-gwas/34519 "2020-02-13T09:31:31Z")

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I am using Julia ( Version 1.0.3) for the first time under linux and I tried to install JWAS package to perform GWAS analysis but unfortantly I got the following error: ERROR: The following package names could not be re…

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## [MethodError: no method matching Gurobi.Env(::Ptr{Nothing})](https://discourse.julialang.org/t/methoderror-no-method-matching-gurobi-env-ptr-nothing/34555)

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**Author:** [@Ken\_Lin](https://discourse.julialang.org/u/Ken_Lin)\
**Replies:** 1\
**Last updated:** [February 13, 2020, 8:37am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-gurobi-env-ptr-nothing/34555 "2020-02-13T08:37:08Z")

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Hello, I tried setting the Gurobi parameter “NonConvex” to 2 and I got the following error: “MethodError: no method matching Gurobi.Env(::Ptr{Nothing})”. My Julia Gurobi version is v0.7.5 and I am using Julia 1.3.1. I g…

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## [Check within struct building](https://discourse.julialang.org/t/check-within-struct-building/34522)

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**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 2\
**Last updated:** [February 13, 2020, 8:36am UTC](https://discourse.julialang.org/t/check-within-struct-building/34522 "2020-02-13T08:36:30Z")

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How to add a check between elements of a structure? For instance, how this example couold work? struct paramChecked a::Real b::Real if(a\>b) error("a \> b") end end Thanks

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## [Using Julia in my Anaconda environment](https://discourse.julialang.org/t/using-julia-in-my-anaconda-environment/34562)

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**Author:** [@Nalt](https://discourse.julialang.org/u/Nalt)\
**Replies:** 1\
**Last updated:** [February 13, 2020, 7:47am UTC](https://discourse.julialang.org/t/using-julia-in-my-anaconda-environment/34562 "2020-02-13T07:47:59Z")

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I want to better understand how my Anconda environment and Julia is interacting. In my conda environment I launch julia via: jupyter notebook. I installed the jupyterthemes Package to my conda environment via: pip insta…

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## [Organizing modules. Is it OK to organize a project using several modules in Julia?](https://discourse.julialang.org/t/organizing-modules-is-it-ok-to-organize-a-project-using-several-modules-in-julia/34535)

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**Author:** [@DevJac](https://discourse.julialang.org/u/DevJac)\
**Replies:** 18\
**Last updated:** [February 13, 2020, 7:34am UTC](https://discourse.julialang.org/t/organizing-modules-is-it-ok-to-organize-a-project-using-several-modules-in-julia/34535 "2020-02-13T07:34:08Z")

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I’ve been trying to organize a small project using several modules. I am doing some experiments with a board game AI in this project. I have something like this: BoardModule.jl: module BoardModule export Board, valid\_m…

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## [@. weird behavior](https://discourse.julialang.org/t/weird-behavior/34490)

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**Author:** [@ric.cioffi](https://discourse.julialang.org/u/ric.cioffi)\
**Replies:** 10\
**Last updated:** [February 13, 2020, 7:05am UTC](https://discourse.julialang.org/t/weird-behavior/34490 "2020-02-13T07:05:48Z")

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From @.'s documentation: “Convert every function call or operator in expr into a “dot call” (e.g. convert f(x) to f.(x) \[…\] If you want to avoid adding dots for selected function calls in expr, splice those function ca…

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## [Solving large(?) problem with Convex.jl and SCS](https://discourse.julialang.org/t/solving-large-problem-with-convex-jl-and-scs/30159)

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**Author:** [@riccardomurri](https://discourse.julialang.org/u/riccardomurri)\
**Replies:** 13\
**Last updated:** [February 13, 2020, 6:37am UTC](https://discourse.julialang.org/t/solving-large-problem-with-convex-jl-and-scs/30159 "2020-02-13T06:37:33Z")

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Hello! I am trying to port some MATLAB code (which uses YALMIP to call into SCS) over to Julia (using Convex.jl and SCS.jl for the purpose). The code builds sparse matrices A, C, D, sparse vector b and tries to solve…

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## [Failed to run program parallely](https://discourse.julialang.org/t/failed-to-run-program-parallely/34560)

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**Author:** [@tool](https://discourse.julialang.org/u/tool)\
**Replies:** 0\
**Last updated:** [February 13, 2020, 6:13am UTC](https://discourse.julialang.org/t/failed-to-run-program-parallely/34560 "2020-02-13T06:13:05Z")

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I’m trying to run command “GB.f4” in GB.jl(GitHub - ederc/GroebnerBasis.jl: Julia wrapper for gb). The command run without problems when it runs sigle thread. julia\> using GB Welcome to Nemo version 0.16.2 Nemo comes…

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## [How to design with immutable and also mutable type?](https://discourse.julialang.org/t/how-to-design-with-immutable-and-also-mutable-type/34465)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 21\
**Last updated:** [February 13, 2020, 6:11am UTC](https://discourse.julialang.org/t/how-to-design-with-immutable-and-also-mutable-type/34465 "2020-02-13T06:11:48Z")

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suppose I have a parametric type as follows: struct A{T \<: AbstractVector{Float32} } data::T end setdata!(a::A, x) = (a.data .= x) here T could be Vector{Float32} or a view etc. however, I would like to use SVect…

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## [How to solve error while running parallel sampling in Julia with Turing and Distributed package?](https://discourse.julialang.org/t/how-to-solve-error-while-running-parallel-sampling-in-julia-with-turing-and-distributed-package/34551)

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**Author:** [@Manu\_Francis](https://discourse.julialang.org/u/Manu_Francis)\
**Replies:** 5\
**Last updated:** [February 13, 2020, 4:42am UTC](https://discourse.julialang.org/t/how-to-solve-error-while-running-parallel-sampling-in-julia-with-turing-and-distributed-package/34551 "2020-02-13T04:42:08Z")

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Hi, I am trying to run samplers in parallel by using example code in Turing documentation (Parallel Sampling). When I run the following example, I am getting an error. The example is as follows: using Distributed addpr…

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## [Debugging AoT compile errors](https://discourse.julialang.org/t/debugging-aot-compile-errors/20829)

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**Author:** [@dhazeghi](https://discourse.julialang.org/u/dhazeghi)\
**Replies:** 2\
**Last updated:** [February 13, 2020, 12:06am UTC](https://discourse.julialang.org/t/debugging-aot-compile-errors/20829 "2020-02-13T00:06:26Z")

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Hi folks, I’m running into some odd errors compiling code to binary (via PackageCompiler) with Julia 1.1. Same code worked fine on 0.6 and works when running normally (not compiling to binary) on 1.1. The errors are r…

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## [JuliaGeo talk at FOSS4G 2019](https://discourse.julialang.org/t/juliageo-talk-at-foss4g-2019/28425)

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**Author:** [@evetion](https://discourse.julialang.org/u/evetion)\
**Replies:** 9\
**Last updated:** [February 12, 2020, 11:49pm UTC](https://discourse.julialang.org/t/juliageo-talk-at-foss4g-2019/28425 "2020-02-12T23:49:47Z")

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Hi all, @visr and me have presented the JuliaGeo ecosystem at the FOSS4G 2019 conference in Bucharest. You can find the video here and the slides (on NextJournal) here. This was the first talk about Julia at FOSS4G as f…

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## [JuMP vs SAS](https://discourse.julialang.org/t/jump-vs-sas/34520)

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**Author:** [@Dominic\_Pazzula](https://discourse.julialang.org/u/Dominic_Pazzula)\
**Replies:** 10\
**Last updated:** [February 12, 2020, 9:58pm UTC](https://discourse.julialang.org/t/jump-vs-sas/34520 "2020-02-12T21:58:15Z")

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New to Julia, so I apologize if this is simple… I am evaluating new technologies to potentially replace SAS for some decision support tools. One in particular is a non-linear optimization of decent (but not huge) size.…

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## [Stumped on eval of function with parameters](https://discourse.julialang.org/t/stumped-on-eval-of-function-with-parameters/34533)

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**Author:** [@a5vzener](https://discourse.julialang.org/u/a5vzener)\
**Replies:** 3\
**Last updated:** [February 12, 2020, 9:24pm UTC](https://discourse.julialang.org/t/stumped-on-eval-of-function-with-parameters/34533 "2020-02-12T21:24:25Z")

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I am trying to provide a feature to allow a user to supply a function expression and have that expression evaluated at runtime. The function needs two arguments, m and n. Both are assigned values before the evaluation. …

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## [Issue with data type in Arrays](https://discourse.julialang.org/t/issue-with-data-type-in-arrays/34537)

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**Author:** [@Nalt](https://discourse.julialang.org/u/Nalt)\
**Replies:** 4\
**Last updated:** [February 12, 2020, 9:17pm UTC](https://discourse.julialang.org/t/issue-with-data-type-in-arrays/34537 "2020-02-12T21:17:44Z")

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I am new to Julia and have been recommended to post here for questions about my Julia related work. Here is my code that attempts to create a stochastic SIR model: https://paste.ofcode.org/riNhvYWMcaxUwP9PU6wKm6 but I g…

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## [Any examples of "package directories"](https://discourse.julialang.org/t/any-examples-of-package-directories/34532)

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**Author:** [@DevJac](https://discourse.julialang.org/u/DevJac)\
**Replies:** 1\
**Last updated:** [February 12, 2020, 8:44pm UTC](https://discourse.julialang.org/t/any-examples-of-package-directories/34532 "2020-02-12T20:44:02Z")

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I was reading Code Loading · The Julia Language , and it looks like just what I needed. If I understand correctly, a “package directory” is a directory of packages, and those “packages” can be as simple as a single Juli…

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## [PackageCompiler v0.6.5 fails to compile local (non-registered) packages](https://discourse.julialang.org/t/packagecompiler-v0-6-5-fails-to-compile-local-non-registered-packages/34124)

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**Author:** [@alkoedl](https://discourse.julialang.org/u/alkoedl)\
**Replies:** 2\
**Last updated:** [February 12, 2020, 8:33pm UTC](https://discourse.julialang.org/t/packagecompiler-v0-6-5-fails-to-compile-local-non-registered-packages/34124 "2020-02-12T20:33:00Z")

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Hi, I have trouble compiling packages which are not registered, i.e. not in the central registry, with PackageCompiler v0.6.5. This is independent of whether the packages are added or dev’ed, whether they are added by p…

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## [On the Computational Efficiency of SparseArrays](https://discourse.julialang.org/t/on-the-computational-efficiency-of-sparsearrays/34531)

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**Author:** [@asavasci](https://discourse.julialang.org/u/asavasci)\
**Replies:** 4\
**Last updated:** [February 12, 2020, 7:27pm UTC](https://discourse.julialang.org/t/on-the-computational-efficiency-of-sparsearrays/34531 "2020-02-12T19:27:16Z")

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I am getting much more averaged computation time by using sparse matrices structure. Is there something wrong on my code? I used a quick test script to test multiplication of both data structure. using SparseArrays, Sta…

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## [Trouble with @eval with mixed variable scopes](https://discourse.julialang.org/t/trouble-with-eval-with-mixed-variable-scopes/34483)

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**Author:** [@arik](https://discourse.julialang.org/u/arik)\
**Replies:** 7\
**Last updated:** [February 12, 2020, 5:17pm UTC](https://discourse.julialang.org/t/trouble-with-eval-with-mixed-variable-scopes/34483 "2020-02-12T17:17:52Z")

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Hi there. I have found some behavior of the “@eval”-macro that I cant quite explain. So, as far as I understand it, “@eval expr” takes a segment of code, and evaluates it as if it had been written at that point in the s…

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## [Range with extra end? Is posible?](https://discourse.julialang.org/t/range-with-extra-end-is-posible/34486)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 5\
**Last updated:** [February 12, 2020, 6:39pm UTC](https://discourse.julialang.org/t/range-with-extra-end-is-posible/34486 "2020-02-12T18:39:33Z")

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How to create silimilar this vector range() julia\> \[1:10:40;45\] 5-element Array{Int64,1}: 1 11 21 31 45 I expect something like : collect(range( x,y,z,;?) 1 11 21 31 45 Thx, Paul

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## [\[ANN\] New benchmarks for LightGraphs](https://discourse.julialang.org/t/ann-new-benchmarks-for-lightgraphs/34526)

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**Author:** [@anon94023334](https://discourse.julialang.org/u/anon94023334)\
**Replies:** 1\
**Last updated:** [February 12, 2020, 4:57pm UTC](https://discourse.julialang.org/t/ann-new-benchmarks-for-lightgraphs/34526 "2020-02-12T16:57:52Z")

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The LightGraphs team has new independent benchmarks to report. Tim Lin published a blog post last year comparing five popular graph packages. All were Python-based; all but one was a two-language (C/C++) package. The res…

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## [Symbolic algebra elaboration?](https://discourse.julialang.org/t/symbolic-algebra-elaboration/34414)

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**Author:** [@Darione](https://discourse.julialang.org/u/Darione)\
**Replies:** 10\
**Last updated:** [February 12, 2020, 4:17pm UTC](https://discourse.julialang.org/t/symbolic-algebra-elaboration/34414 "2020-02-12T16:17:05Z")

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Hi all … My daughter is in the first scientific high school, here in Italy. Yesterday, we were to see the expansion of (x+y)^7 with tartaglia triangle method … very nice … but I’d like to use Julia to do other symbolic …

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## [For Knet.jl connoisseurs : problem with WTYPE error](https://discourse.julialang.org/t/for-knet-jl-connoisseurs-problem-with-wtype-error/34523)

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**Author:** [@Johncowk](https://discourse.julialang.org/u/Johncowk)\
**Replies:** 0\
**Last updated:** [February 12, 2020, 3:46pm UTC](https://discourse.julialang.org/t/for-knet-jl-connoisseurs-problem-with-wtype-error/34523 "2020-02-12T15:46:19Z")

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I am trying to build a RNN with self-attention mechanism using knet (maybe I should have sticked to python …) and after fixing all sorts of puzzling error I am faced with the following one : AssertionError: r.c == nothi…

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## [Are fields with structtypes to be avoided as well?](https://discourse.julialang.org/t/are-fields-with-structtypes-to-be-avoided-as-well/34515)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 3\
**Last updated:** [February 12, 2020, 3:11pm UTC](https://discourse.julialang.org/t/are-fields-with-structtypes-to-be-avoided-as-well/34515 "2020-02-12T15:11:01Z")

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In the manual it is recommended to avoid abstract type fields: Performance Tips · The Julia Language. It is not precised if this is also the case for struct type. Example: julia\> struct Foo{T} x::T end julia\> isabstrac…

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## [StatsBase.jl sample size \> 31 throws error](https://discourse.julialang.org/t/statsbase-jl-sample-size-31-throws-error/34484)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 3\
**Last updated:** [February 12, 2020, 12:52pm UTC](https://discourse.julialang.org/t/statsbase-jl-sample-size-31-throws-error/34484 "2020-02-12T12:52:16Z")

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I’m running into an issue that I’m hoping someone can help me understand. I have a 1308 x 22 DataFrame that I’m trying to sample from with StatsBase. All is well and fine as long as n \<= 31. The code looks like this: j…

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