# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1724

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

**Page:** 1725

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## [Simple 2nd Order Differential Equation syntax?](https://discourse.julialang.org/t/simple-2nd-order-differential-equation-syntax/41024)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 16\
**Last updated:** [June 9, 2020, 1:24am UTC](https://discourse.julialang.org/t/simple-2nd-order-differential-equation-syntax/41024 "2020-06-09T01:24:31Z")

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Hi, new to Julia; the instructions on how to use “SecondOrderODE” on the julia Diff Eq package website are very incomplete. What is wrong with the very simple program below? Thanks. BTW, I’m just trying to model the Sim…

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## ["Go to definition" partial coverage](https://discourse.julialang.org/t/go-to-definition-partial-coverage/41018)

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**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 0\
**Last updated:** [June 8, 2020, 9:10pm UTC](https://discourse.julialang.org/t/go-to-definition-partial-coverage/41018 "2020-06-08T21:10:09Z")

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I noticed that for the code snippets I’m playing with, Go to definition often gives me No definition found message. For example, in this snippet: using Meshing A = rand(50,50,50) # 3D Matrix points,faces = isosurface(A…

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## [Pass variables at command line](https://discourse.julialang.org/t/pass-variables-at-command-line/41025)

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**Author:** [@dataSurfer](https://discourse.julialang.org/u/dataSurfer)\
**Replies:** 2\
**Last updated:** [June 9, 2020, 12:48am UTC](https://discourse.julialang.org/t/pass-variables-at-command-line/41025 "2020-06-09T00:48:10Z")

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Is it possible to pass variables to a julia script at command line?

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## [Base.run() generates "failed process" error in Juno REPL on some platforms](https://discourse.julialang.org/t/base-run-generates-failed-process-error-in-juno-repl-on-some-platforms/40973)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 2\
**Last updated:** [June 9, 2020, 12:28am UTC](https://discourse.julialang.org/t/base-run-generates-failed-process-error-in-juno-repl-on-some-platforms/40973 "2020-06-09T00:28:20Z")

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MWE (Ubuntu 20.04, Julia 1.4): julia\> Base.run(ls) Desktop Documents … MWE (OSX 10.14, Julia 1.4): julia\> Base.run(ls) ERROR: failed process: Process(ls, ProcessSignaled(9)) \[0\]

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## [Import Board Package on Julia and use Infinity](https://discourse.julialang.org/t/import-board-package-on-julia-and-use-infinity/40929)

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**Author:** [@Moreno](https://discourse.julialang.org/u/Moreno)\
**Replies:** 6\
**Last updated:** [June 8, 2020, 11:16pm UTC](https://discourse.julialang.org/t/import-board-package-on-julia-and-use-infinity/40929 "2020-06-08T23:16:56Z")

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Hi Guys, am new to Julia and am developing a Tic Tac Toe AI board game and i happen to have issues with importing board.I know in python it’s import board how do i do this in Julia?

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## [Pcolormesh equivalence in Plots?](https://discourse.julialang.org/t/pcolormesh-equivalence-in-plots/40941)

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**Author:** [@axidio](https://discourse.julialang.org/u/axidio)\
**Replies:** 4\
**Last updated:** [June 8, 2020, 10:37pm UTC](https://discourse.julialang.org/t/pcolormesh-equivalence-in-plots/40941 "2020-06-08T22:37:19Z")

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Is there a pcolormesh equivalence in Plots? I need to plot data in the format x1 y1 z1 x2 y2 z2 … where the (x, y) grid is not a rectangle. So heatmap is not an option. Thank you!

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## [Moore's Law is deader than corduroy bell bottoms. But with a bit of smart coding it's not the end of the road](https://discourse.julialang.org/t/moores-law-is-deader-than-corduroy-bell-bottoms-but-with-a-bit-of-smart-coding-its-not-the-end-of-the-road/40983)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 7\
**Last updated:** [June 8, 2020, 9:53pm UTC](https://discourse.julialang.org/t/moores-law-is-deader-than-corduroy-bell-bottoms-but-with-a-bit-of-smart-coding-its-not-the-end-of-the-road/40983 "2020-06-08T21:53:52Z")

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I rather like my corduroy bellbottom trousers… I can’t read the paper. It says 7 hours to run that Python code - and curiously longer in Python3.

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## [ANN: mybinder.org support for Julia 1.x and Project.toml](https://discourse.julialang.org/t/ann-mybinder-org-support-for-julia-1-x-and-project-toml/22522)

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**Author:** [@davidanthoff](https://discourse.julialang.org/u/davidanthoff)\
**Replies:** 40\
**Last updated:** [June 8, 2020, 9:35pm UTC](https://discourse.julialang.org/t/ann-mybinder-org-support-for-julia-1-x-and-project-toml/22522 "2020-06-08T21:35:48Z")

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mybinder.org now supports julia 1.x, including Project.toml and Manifest.toml files, out of the box. How do you use it? You create a github repo, put a Project.toml and Manifest.toml in the root and add some Jupyter Not…

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## [Workflow Suggestions: Post-processing ANSYS mechanical engineering data with Julia](https://discourse.julialang.org/t/workflow-suggestions-post-processing-ansys-mechanical-engineering-data-with-julia/41014)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 0\
**Last updated:** [June 8, 2020, 7:29pm UTC](https://discourse.julialang.org/t/workflow-suggestions-post-processing-ansys-mechanical-engineering-data-with-julia/41014 "2020-06-08T19:29:57Z")

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I am new to both ANSYS and Julia. I would like to use Julia to process static structural and heat transfer data from the commercial ANSYS finite element software. I have computed several quantities of interest within ANS…

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## [How to change the type from MOIU.CachingOptimizer{MOI.AbstractOptimizer,...} to MOI.AbstractoOptimizer](https://discourse.julialang.org/t/how-to-change-the-type-from-moiu-cachingoptimizer-moi-abstractoptimizer-to-moi-abstractooptimizer/37179)

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**Author:** [@sugyeong-jo](https://discourse.julialang.org/u/sugyeong-jo)\
**Replies:** 1\
**Last updated:** [June 8, 2020, 7:22pm UTC](https://discourse.julialang.org/t/how-to-change-the-type-from-moiu-cachingoptimizer-moi-abstractoptimizer-to-moi-abstractooptimizer/37179 "2020-06-08T19:22:03Z")

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I want to make a solver looking for a feasibility solution. Therefore, I want to bring up the problem of mps format and treat constraints, variables, coefficients, etc. as follows. The structure I want is the same struc…

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## [Calling pmap from thread hangs](https://discourse.julialang.org/t/calling-pmap-from-thread-hangs/41012)

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**Author:** [@samuel\_okon](https://discourse.julialang.org/u/samuel_okon)\
**Replies:** 0\
**Last updated:** [June 8, 2020, 6:54pm UTC](https://discourse.julialang.org/t/calling-pmap-from-thread-hangs/41012 "2020-06-08T18:54:15Z")

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Hi, for some reason the code snippet below hangs. Does any one have an explanation as to why this hangs using distributed addprocs(2) tasks = Vector{Task}(undef,4) @sync for i in 1:4 tasks\[i\] = Threads.@spawn beg…

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## [ITensors.jl: Custom SiteTypes](https://discourse.julialang.org/t/itensors-jl-custom-sitetypes/39717)

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**Author:** [@amitjamadagni](https://discourse.julialang.org/u/amitjamadagni)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 6:14pm UTC](https://discourse.julialang.org/t/itensors-jl-custom-sitetypes/39717 "2020-06-08T18:14:14Z")

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Hello, I have been tweaking around with ITensors.jl package (GitHub - ITensor/ITensors.jl: A Julia library for efficient tensor computations and tensor network calculations) to create custom SitesTypes. I have tried the…

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## [Best way to import the dogscats dataset](https://discourse.julialang.org/t/best-way-to-import-the-dogscats-dataset/41006)

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**Author:** [@natema](https://discourse.julialang.org/u/natema)\
**Replies:** 0\
**Last updated:** [June 8, 2020, 5:33pm UTC](https://discourse.julialang.org/t/best-way-to-import-the-dogscats-dataset/41006 "2020-06-08T17:33:19Z")

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I would like to reproduce in julia some pytorch transfer-learning experiments which use Resnet18 on the Kaggle’s Dogs vs. Cats dataset (direct download from fast.ai). I would like some feedback on how I’m importing the …

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## [Interested in Constraints Programming & Optimization, have some basic questions](https://discourse.julialang.org/t/interested-in-constraints-programming-optimization-have-some-basic-questions/36274)

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**Author:** [@GavinRay](https://discourse.julialang.org/u/GavinRay)\
**Replies:** 6\
**Last updated:** [June 8, 2020, 4:56pm UTC](https://discourse.julialang.org/t/interested-in-constraints-programming-optimization-have-some-basic-questions/36274 "2020-06-08T16:56:08Z")

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I apologize in advance for how likely stupid this is going to come off, but I have a few questions and was hoping someone might be kind enough to offer some insight. I became interested in Logic/Constraints programming …

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## [Getting a strange error when trying to join list of DataFrames, what could this be?](https://discourse.julialang.org/t/getting-a-strange-error-when-trying-to-join-list-of-dataframes-what-could-this-be/40997)

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**Author:** [@Julia1](https://discourse.julialang.org/u/Julia1)\
**Replies:** 6\
**Last updated:** [June 8, 2020, 4:49pm UTC](https://discourse.julialang.org/t/getting-a-strange-error-when-trying-to-join-list-of-dataframes-what-could-this-be/40997 "2020-06-08T16:49:38Z")

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Hi how’s it going? I’m trying to join a list of DataFrames on a unique column, but it won’t even let me set a single one of those DataFrames to a variable and instead gives me this error. “AbstractDataFrame is not iter…

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## [Invalid named tuple error](https://discourse.julialang.org/t/invalid-named-tuple-error/41000)

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**Author:** [@Savvy21](https://discourse.julialang.org/u/Savvy21)\
**Replies:** 3\
**Last updated:** [June 8, 2020, 4:33pm UTC](https://discourse.julialang.org/t/invalid-named-tuple-error/41000 "2020-06-08T16:33:40Z")

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Can anyone help me with this error, I am trying to get a plot here .

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## [Stubborn 1-based LinearIndices for the custom type with non-zero based indexing](https://discourse.julialang.org/t/stubborn-1-based-linearindices-for-the-custom-type-with-non-zero-based-indexing/40593)

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**Author:** [@goubochlepp](https://discourse.julialang.org/u/goubochlepp)\
**Replies:** 7\
**Last updated:** [June 8, 2020, 4:03pm UTC](https://discourse.julialang.org/t/stubborn-1-based-linearindices-for-the-custom-type-with-non-zero-based-indexing/40593 "2020-06-08T16:03:46Z")

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Greetings and apologies if this is very basic. I am trying to create a custom type subtyped from AbstractArray to dispatch on it in place of a dense array at times. I’ve been following instructions in the manual for spe…

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## [Statistics on random matrices](https://discourse.julialang.org/t/statistics-on-random-matrices/40776)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 6\
**Last updated:** [June 8, 2020, 3:46pm UTC](https://discourse.julialang.org/t/statistics-on-random-matrices/40776 "2020-06-08T15:46:25Z")

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Hi, I am generating a lot of random matrices and want to study their statistical properties. Right now I am storing them in a 3-dimensional array, where the first two dimensions are the matrix sizes, let’s say square ma…

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## [Write to MPS](https://discourse.julialang.org/t/write-to-mps/40995)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 1\
**Last updated:** [June 8, 2020, 3:37pm UTC](https://discourse.julialang.org/t/write-to-mps/40995 "2020-06-08T15:37:02Z")

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How does the MPS writer of Gurobi work? using JuMP, Gurobi model = Model(Gurobi.Optimizer) @variables(model, begin 0 \<= x \<= 5 0 \<= y \<= 10, Int z, Bin end) @objective(model, Max, x + 2y + 5z) @constraint…

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## [Type stable difference of tuples](https://discourse.julialang.org/t/type-stable-difference-of-tuples/3933)

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**Author:** [@jebej](https://discourse.julialang.org/u/jebej)\
**Replies:** 9\
**Last updated:** [June 8, 2020, 3:19pm UTC](https://discourse.julialang.org/t/type-stable-difference-of-tuples/3933 "2020-06-08T15:19:05Z")

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Hello everyone, I am trying to figure out how to take the difference between two tuples of integers in a type-stable way, assuming that, if tuple a has length n, and tuple b has length m, then tuple c = setdiff(a,b) will…

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## [Julia on edx.org platform](https://discourse.julialang.org/t/julia-on-edx-org-platform/22980)

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**Author:** [@jamm](https://discourse.julialang.org/u/jamm)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 3:11pm UTC](https://discourse.julialang.org/t/julia-on-edx-org-platform/22980 "2020-06-08T15:11:30Z")

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Just for a note. It will be great if Julia would available as part of data science programs on edx.org. For example, the great program Statistics and Data Science (MITx) includes only Python. It will be really good if J…

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## [ModelingToolkit: using it with parallel ensemble simulations](https://discourse.julialang.org/t/modelingtoolkit-using-it-with-parallel-ensemble-simulations/40963)

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**Author:** [@MFairley](https://discourse.julialang.org/u/MFairley)\
**Replies:** 4\
**Last updated:** [June 8, 2020, 3:07pm UTC](https://discourse.julialang.org/t/modelingtoolkit-using-it-with-parallel-ensemble-simulations/40963 "2020-06-08T15:07:04Z")

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I’m testing out ModelingToolkit to see if I can get a performance improvement. I’ve converted my prob using modelingtoolkitize(prob). I’m wondering if the ModelingToolkit prob is compatible with EnsembleProblem, and what…

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## [A question about Fuzzy C-means code](https://discourse.julialang.org/t/a-question-about-fuzzy-c-means-code/40988)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 2:47pm UTC](https://discourse.julialang.org/t/a-question-about-fuzzy-c-means-code/40988 "2020-06-08T14:47:48Z")

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using RDatasets, Clustering, Plots using DataFrames using CSV iris = dataset("datasets", "iris"); # load the data features = collect(Matrix(iris\[:, 1:4\])'); # features to use for clustering result = fuzzy\_cmeans(features…

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## [Statistics.var wasting time calculating the mean?](https://discourse.julialang.org/t/statistics-var-wasting-time-calculating-the-mean/40944)

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**Author:** [@sijo](https://discourse.julialang.org/u/sijo)\
**Replies:** 8\
**Last updated:** [June 8, 2020, 2:22pm UTC](https://discourse.julialang.org/t/statistics-var-wasting-time-calculating-the-mean/40944 "2020-06-08T14:22:23Z")

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I was trying to understand why Statistics.jl has both var and varm functions (since var already accepts a mean parameter). Doing @less var(\[1,2,3\]) I see: var(A::AbstractArray; corrected::Bool=true, mean=nothing, dims=:…

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## [Memory error out of gc handles](https://discourse.julialang.org/t/memory-error-out-of-gc-handles/40985)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 4\
**Last updated:** [June 8, 2020, 2:14pm UTC](https://discourse.julialang.org/t/memory-error-out-of-gc-handles/40985 "2020-06-08T14:14:10Z")

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I know I will be shown for a fool here… My laptop runs Windows 10 , Julia 1.5 32 gigabytesof RAM Using StaticArrays I cannot allocate a 100 by 100 array julia\> using StaticArrays julia\> @allocated A=@SMatrix zeros(…

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## [The delightful conciseness of Julia](https://discourse.julialang.org/t/the-delightful-conciseness-of-julia/40947)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 1:59pm UTC](https://discourse.julialang.org/t/the-delightful-conciseness-of-julia/40947 "2020-06-08T13:59:14Z")

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The code does the same thing: Integrate the conductivity matrix and the heat load. The deal.ii code on the right is in C++. The Julia is I think easier to read, and, at least in my test, it runs (slightly) faster. E…

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## [Method specificity is acyclic, isn't it?](https://discourse.julialang.org/t/method-specificity-is-acyclic-isnt-it/38518)

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**Author:** [@krstoff](https://discourse.julialang.org/u/krstoff)\
**Replies:** 1\
**Last updated:** [June 8, 2020, 4:04am UTC](https://discourse.julialang.org/t/method-specificity-is-acyclic-isnt-it/38518 "2020-06-08T04:04:13Z")

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New user here. (How new? Try… yesterday.) Someone recommended me this talk from JuliaCon 2019 by Bezanson and I was a little spooked by a point made at 22:58. Here is his hypothetical type tree (with an ex…

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## [Module loading \`import Module: foo\`](https://discourse.julialang.org/t/module-loading-import-module-foo/40957)

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**Author:** [@jamblejoe](https://discourse.julialang.org/u/jamblejoe)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 1:42pm UTC](https://discourse.julialang.org/t/module-loading-import-module-foo/40957 "2020-06-08T13:42:53Z")

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Hi, I have a function e.g. solve in one of my modules and will use that module together with DifferentailEquations. The function in my module does something similar, that’s why the same name. To not override solve, I fi…

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## [How to find the intercept of two functions?](https://discourse.julialang.org/t/how-to-find-the-intercept-of-two-functions/40718)

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**Author:** [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Replies:** 6\
**Last updated:** [June 8, 2020, 12:30pm UTC](https://discourse.julialang.org/t/how-to-find-the-intercept-of-two-functions/40718 "2020-06-08T12:30:16Z")

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How do I find the intercept of two functions? I thought it would be something simple like findall(in(a), b) but this gives me Vector{Int64} with 0 elements MWE attack\_max2 = 0.90 attack\_min2 = 0.52 β\_V2 = 2.0 b0V2 = 16…

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## [How to manually install artifacts](https://discourse.julialang.org/t/how-to-manually-install-artifacts/40984)

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**Author:** [@melonedo](https://discourse.julialang.org/u/melonedo)\
**Replies:** 2\
**Last updated:** [June 8, 2020, 12:18pm UTC](https://discourse.julialang.org/t/how-to-manually-install-artifacts/40984 "2020-06-08T12:18:05Z")

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I am installing Flux.jl and I have very slow access to github (~50kB/s). Now after installing the package (slow, but acceptable), it starts downloading artifact CUDA10.2. The problem is CUDA10.2 package is around 0.5GB, …

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