# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1516

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

**Page:** 1517

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## [Plotting a distribution of planes](https://discourse.julialang.org/t/plotting-a-distribution-of-planes/53689)

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**Author:** [@mlainz](https://discourse.julialang.org/u/mlainz)\
**Replies:** 2\
**Last updated:** [January 21, 2021, 3:33pm UTC](https://discourse.julialang.org/t/plotting-a-distribution-of-planes/53689 "2021-01-21T15:33:56Z")

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A distribution of planes is an map that assigns a plane to each point of space. For example: A distribution can be defined by giving a field of normal vectors to the planes (more precisely, a one-form). In the case ab…

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## [The probability of density function](https://discourse.julialang.org/t/the-probability-of-density-function/53725)

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**Author:** [@marouane1994](https://discourse.julialang.org/u/marouane1994)\
**Replies:** 5\
**Last updated:** [January 21, 2021, 3:30pm UTC](https://discourse.julialang.org/t/the-probability-of-density-function/53725 "2021-01-21T15:30:04Z")

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I want to test an MCMC code for a Gaussian distribution witha standard deviation of 0.1and for random values of the mean using Distributions using LinearAlgebra using Plots sigma=0.1 log\_target(mu)= log((1/sigma\*sqrt(p…

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## [Least Squares Minimization of operator norm](https://discourse.julialang.org/t/least-squares-minimization-of-operator-norm/53723)

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**Author:** [@cheng\_chen](https://discourse.julialang.org/u/cheng_chen)\
**Replies:** 3\
**Last updated:** [January 21, 2021, 3:24pm UTC](https://discourse.julialang.org/t/least-squares-minimization-of-operator-norm/53723 "2021-01-21T15:24:56Z")

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Here is a minimal example of my problem: I want to find a minimizer x that minimizes the objective function : opnorm(A\*x-b,2)^2 I tried Convex.jl, but it doesn’t work for the operator norm.

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## [How @code\_warntype , precompilation, execution and type interference works?](https://discourse.julialang.org/t/how-code-warntype-precompilation-execution-and-type-interference-works/53674)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 11\
**Last updated:** [January 21, 2021, 2:54pm UTC](https://discourse.julialang.org/t/how-code-warntype-precompilation-execution-and-type-interference-works/53674 "2021-01-21T14:54:38Z")

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Hey Julianners, I found a really strange behavior! But shit is pretty serious thing all in all. using InteractiveUtils struct me{I,O} a::Vector{Array{Float32,I}} b::Vector{Array{Float32,O}} end double(x::Vector{Arra…

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## [Why does my program's performance vary so much from run to run? Can it be fixed?](https://discourse.julialang.org/t/why-does-my-programs-performance-vary-so-much-from-run-to-run-can-it-be-fixed/53678)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 11\
**Last updated:** [January 20, 2021, 11:02pm UTC](https://discourse.julialang.org/t/why-does-my-programs-performance-vary-so-much-from-run-to-run-can-it-be-fixed/53678 "2021-01-20T23:02:01Z")

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While I was looking into optimizing my pure Julia program, I noticed something very unpleasant: its run time varies a great deal between some runs even though its input and code stay the same, and even though the system …

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## [Can anyone tell me what is this distribution?](https://discourse.julialang.org/t/can-anyone-tell-me-what-is-this-distribution/53726)

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**Author:** [@abulak](https://discourse.julialang.org/u/abulak)\
**Replies:** 0\
**Last updated:** [January 21, 2021, 2:14pm UTC](https://discourse.julialang.org/t/can-anyone-tell-me-what-is-this-distribution/53726 "2021-01-21T14:14:15Z")

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In my hobby project I arrived at the following problem: I’m given a family of random variables: Wₖ for which I need to estimate cdf: (the above is histogram approximation of pdf from 10^7 samples) From theoretical con…

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## [Github actions StackOverflowError](https://discourse.julialang.org/t/github-actions-stackoverflowerror/53720)

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**Author:** [@arzwa](https://discourse.julialang.org/u/arzwa)\
**Replies:** 2\
**Last updated:** [January 21, 2021, 2:07pm UTC](https://discourse.julialang.org/t/github-actions-stackoverflowerror/53720 "2021-01-21T14:07:04Z")

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I’m trying to set up a GitHub actions workflow for testing a package. While my documentation builds fine, my tests error in a way I don’t understand. I get a StackOverflowError I cannot reproduce, and which does not make…

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## [PSA: CUDA.jl replacing CuArrays.jl/CUDAnative.jl/CUDAdrv.jl/CUDAapi.jl -- call for testing!](https://discourse.julialang.org/t/psa-cuda-jl-replacing-cuarrays-jl-cudanative-jl-cudadrv-jl-cudaapi-jl-call-for-testing/40205)

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**Author:** [@maleadt](https://discourse.julialang.org/u/maleadt)\
**Replies:** 21\
**Last updated:** [January 21, 2021, 1:28pm UTC](https://discourse.julialang.org/t/psa-cuda-jl-replacing-cuarrays-jl-cudanative-jl-cudadrv-jl-cudaapi-jl-call-for-testing/40205 "2021-01-21T13:28:45Z")

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Hi all, I just registered and tagged v0.1 of CUDA.jl, a package that now contains the documentation and functionality from the several packages that make up the Julia/CUDA stack. I merged them because there was too much…

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## [Solving ode takes too long compared to python](https://discourse.julialang.org/t/solving-ode-takes-too-long-compared-to-python/53719)

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**Author:** [@arif](https://discourse.julialang.org/u/arif)\
**Replies:** 7\
**Last updated:** [January 21, 2021, 1:08pm UTC](https://discourse.julialang.org/t/solving-ode-takes-too-long-compared-to-python/53719 "2021-01-21T13:08:04Z")

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Hi, I have tried Julia on and off for the last 5 years. Recently I thought of using Julia exclusively for a course on Astrophysics and my first task was to solve a set of four ordinary differential equations. I am using …

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## [Unable to compile](https://discourse.julialang.org/t/unable-to-compile/53617)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 3\
**Last updated:** [January 21, 2021, 9:58am UTC](https://discourse.julialang.org/t/unable-to-compile/53617 "2021-01-21T09:58:26Z")

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Hello, Total noob here. I’m writing some Julia code and I wanted to make sure I can compile it (I’ll need to ship it in the future and can’t guarantee a local install). I can’t get the compiler to work. The latest erro…

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## [Run file and print line results as in REPL](https://discourse.julialang.org/t/run-file-and-print-line-results-as-in-repl/53651)

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**Author:** [@RaulDurand](https://discourse.julialang.org/u/RaulDurand)\
**Replies:** 4\
**Last updated:** [January 21, 2021, 8:29am UTC](https://discourse.julialang.org/t/run-file-and-print-line-results-as-in-repl/53651 "2021-01-21T08:29:00Z")

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How can I run a file and obtain the results in the screen as if the file were executed line by line in the REPL? For example, if I have the file “file.jl”: a = 1 b = 1 c = a+b and run it from the shell ~$ julia file.j…

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## [\`@btime\` appears to force specialization, does this give misleading timings?](https://discourse.julialang.org/t/btime-appears-to-force-specialization-does-this-give-misleading-timings/53611)

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**Author:** [@Benny](https://discourse.julialang.org/u/Benny)\
**Replies:** 5\
**Last updated:** [January 21, 2021, 8:41am UTC](https://discourse.julialang.org/t/btime-appears-to-force-specialization-does-this-give-misleading-timings/53611 "2021-01-21T08:41:02Z")

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Julia normally avoids specializing on Type, but it can be triggered by @code\_warntype and similar macros (has a mention in Performance Tips; currently open issue 32834; illustrated well in issue 23749). It also appears t…

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## [Puzzling on a product likelihood using Distributions and Turing](https://discourse.julialang.org/t/puzzling-on-a-product-likelihood-using-distributions-and-turing/52183)

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**Author:** [@riegel\_gestr](https://discourse.julialang.org/u/riegel_gestr)\
**Replies:** 2\
**Last updated:** [January 21, 2021, 7:18am UTC](https://discourse.julialang.org/t/puzzling-on-a-product-likelihood-using-distributions-and-turing/52183 "2021-01-21T07:18:47Z")

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I am currently working on a simple bayesian problem in which my likelihood is the product of N poisson distributions, so I got the following: likelihood(x) ~ product\_i(Poisson(mean\_i)) where x is a vector, representing t…

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## [Problems with Julia 1.5.3 installation](https://discourse.julialang.org/t/problems-with-julia-1-5-3-installation/53606)

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**Author:** [@Slawomir\_Kwiecien](https://discourse.julialang.org/u/Slawomir_Kwiecien)\
**Replies:** 10\
**Last updated:** [January 21, 2021, 6:15am UTC](https://discourse.julialang.org/t/problems-with-julia-1-5-3-installation/53606 "2021-01-21T06:15:47Z")

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I watched movie about installation Julia and nteract (julia academy). After typing a command “add IJulia” Julia gives information about problems (see attached pictures). Connection with nteract does not work too (last a…

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## [Auckland Julia meetup #2, Thursday January 21](https://discourse.julialang.org/t/auckland-julia-meetup-2-thursday-january-21/53422)

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**Author:** [@mortenpi](https://discourse.julialang.org/u/mortenpi)\
**Replies:** 3\
**Last updated:** [January 21, 2021, 4:45am UTC](https://discourse.julialang.org/t/auckland-julia-meetup-2-thursday-january-21/53422 "2021-01-21T04:45:41Z")

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Tēnā koutou, We’re happy to announce the second Auckland Julia meetup which will take place on Thursday, 21 January at 6:30pm, at Massey University (Albany campus). The meetup will feature a talk by Dr. Ashton Bradley …

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## [Access JuMP canonical matricial LP problem](https://discourse.julialang.org/t/access-jump-canonical-matricial-lp-problem/53688)

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**Author:** [@josePereiro](https://discourse.julialang.org/u/josePereiro)\
**Replies:** 2\
**Last updated:** [January 21, 2021, 2:28am UTC](https://discourse.julialang.org/t/access-jump-canonical-matricial-lp-problem/53688 "2021-01-21T02:28:05Z")

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Hi, just wondering if there is a way to ‘extract’ the canonical matricial(\*) LP form from a JuMP model. (\*) With canonical form I meant something like: \\text{maximize } c^Tv \\text{, subject to:} \\\\ Sv = b \\\\ lb \\le v …

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## [Evolutionary.jl - positive integers](https://discourse.julialang.org/t/evolutionary-jl-positive-integers/53652)

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**Author:** [@TheMEGuy](https://discourse.julialang.org/u/TheMEGuy)\
**Replies:** 3\
**Last updated:** [January 21, 2021, 2:01am UTC](https://discourse.julialang.org/t/evolutionary-jl-positive-integers/53652 "2021-01-21T02:01:42Z")

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Hi, is there a way to tell the optimizer, that the variables should be natural numbers? I am currently trying to implement this using PenaltyConstraints(). Is there another way? Thanks

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## [How to make a function accept children of an abstract type?](https://discourse.julialang.org/t/how-to-make-a-function-accept-children-of-an-abstract-type/53698)

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**Author:** [@Visipi](https://discourse.julialang.org/u/Visipi)\
**Replies:** 4\
**Last updated:** [January 21, 2021, 1:53am UTC](https://discourse.julialang.org/t/how-to-make-a-function-accept-children-of-an-abstract-type/53698 "2021-01-21T01:53:35Z")

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I have an abstract type “Foo” that has a number of children: “Bar”, “Car”, “Dar”. I also have a function “f” that takes an array of “Foo” objects as arguments. function f(a::Array{Foo, 1}) But when I try to run the fu…

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## [Multiple dispatch with module and external functions](https://discourse.julialang.org/t/multiple-dispatch-with-module-and-external-functions/53694)

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**Author:** [@Abhishek\_Goudar](https://discourse.julialang.org/u/Abhishek_Goudar)\
**Replies:** 4\
**Last updated:** [January 21, 2021, 12:59am UTC](https://discourse.julialang.org/t/multiple-dispatch-with-module-and-external-functions/53694 "2021-01-21T00:59:40Z")

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Hello everyone, Julia newbie here. My problem revolves around multiple dispatch. The following is a pseudo-code and might not adhere to the proper syntax. custom\_module.jl module custom\_module export Residual export …

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## [Plots.jl: How can I get discrete colors in the colorbar of a heatmap?](https://discourse.julialang.org/t/plots-jl-how-can-i-get-discrete-colors-in-the-colorbar-of-a-heatmap/29660)

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**Author:** [@NiclasMattsson](https://discourse.julialang.org/u/NiclasMattsson)\
**Replies:** 15\
**Last updated:** [January 21, 2021, 12:33am UTC](https://discourse.julialang.org/t/plots-jl-how-can-i-get-discrete-colors-in-the-colorbar-of-a-heatmap/29660 "2021-01-21T00:33:41Z")

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Simple example: julia\> r = rand(0:10,10,10) 10×10 Array{Int64,2}: 0 4 10 1 10 1 6 3 6 3 9 7 9 3 8 4 3 1 6 8 8 7 6 2 8 7 8 8 2 9 3 7 2 0 0 7 8 0 9 5 …

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## [Signal (7): Bus error](https://discourse.julialang.org/t/signal-7-bus-error/53695)

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**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 0\
**Last updated:** [January 21, 2021, 12:33am UTC](https://discourse.julialang.org/t/signal-7-bus-error/53695 "2021-01-21T00:33:18Z")

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hi guys, I hope you are all are still alive and healthy after this terrible ordeal with covid-19 thingy. I have a question regarding data save using JLD2 package. Please see following the error that I get sometime durin…

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## [Replace missing values with zeros and nonmissing values with one in Dataframe](https://discourse.julialang.org/t/replace-missing-values-with-zeros-and-nonmissing-values-with-one-in-dataframe/53686)

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**Author:** [@max\_schwarzer](https://discourse.julialang.org/u/max_schwarzer)\
**Replies:** 1\
**Last updated:** [January 20, 2021, 9:05pm UTC](https://discourse.julialang.org/t/replace-missing-values-with-zeros-and-nonmissing-values-with-one-in-dataframe/53686 "2021-01-20T21:05:43Z")

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Hello, I would like to recode a dataframe containing positive numbers and missings such that every positive number is replaced with one and every missing is replaced with zero. I found some similar solutions but was un…

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## [String column dataframe: replace for another string built from a substring from each row](https://discourse.julialang.org/t/string-column-dataframe-replace-for-another-string-built-from-a-substring-from-each-row/53684)

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**Author:** [@mocalvao](https://discourse.julialang.org/u/mocalvao)\
**Replies:** 1\
**Last updated:** [January 20, 2021, 8:18pm UTC](https://discourse.julialang.org/t/string-column-dataframe-replace-for-another-string-built-from-a-substring-from-each-row/53684 "2021-01-20T20:18:06Z")

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I have a dataframe of String columns, such as (in fact, it has many more rows and columns): julia\> using DataFrames julia\> df = DataFrame(DRE=\["119018524", "120034962"\], Q1=\["0.50", "0.00"\]) 2×2 DataFrame │ Row │ DRE …

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## [Question about method dispatch with composite types](https://discourse.julialang.org/t/question-about-method-dispatch-with-composite-types/53680)

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**Author:** [@askvorts](https://discourse.julialang.org/u/askvorts)\
**Replies:** 2\
**Last updated:** [January 20, 2021, 7:01pm UTC](https://discourse.julialang.org/t/question-about-method-dispatch-with-composite-types/53680 "2021-01-20T19:01:43Z")

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In the bellow script, being dc.x and dc.y equal to 1 the default, how may I (if possible) create the following methods: divide(a,Clock()) and divide(a,Pendulum()) returning the same as divide(a,CLock(1)), divide(a,Pen…

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## [Increase thickness of axises](https://discourse.julialang.org/t/increase-thickness-of-axises/53683)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 0\
**Last updated:** [January 20, 2021, 7:50pm UTC](https://discourse.julialang.org/t/increase-thickness-of-axises/53683 "2021-01-20T19:50:35Z")

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How do I increase the thickness of the axis using plots? I have found all kinds of options under attributes, e.g. I can change color with foreground\_color\_border=:red, but the thickness I haven’t found anything for.

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## [Plotting the solution of a differential equation](https://discourse.julialang.org/t/plotting-the-solution-of-a-differential-equation/53627)

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**Author:** [@martinmestre](https://discourse.julialang.org/u/martinmestre)\
**Replies:** 13\
**Last updated:** [January 20, 2021, 7:19pm UTC](https://discourse.julialang.org/t/plotting-the-solution-of-a-differential-equation/53627 "2021-01-20T19:19:48Z")

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I have written the Julia example for solving the Lorenz equation as in the page: https://diffeq.sciml.ai/stable/tutorials/ode\_example/#Example-2:-Solving-Systems-of-Equations : function lorenz!(du,u,p,t) du\[1\] = 10.0\*(…

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## [Error: Unsatisfiable requirements detected for package MathOptInterface](https://discourse.julialang.org/t/error-unsatisfiable-requirements-detected-for-package-mathoptinterface/46469)

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**Author:** [@Raj95](https://discourse.julialang.org/u/Raj95)\
**Replies:** 11\
**Last updated:** [January 20, 2021, 7:18pm UTC](https://discourse.julialang.org/t/error-unsatisfiable-requirements-detected-for-package-mathoptinterface/46469 "2021-01-20T19:18:49Z")

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Hello…I’m getting the following error while trying to add MathOptInterface: Pkg.add("MathOptInterface") ERROR: Unsatisfiable requirements detected for package MathOptInterface \[b8f27783\]: MathOptInterface \[b8f27783\] l…

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## [Different loss function for training ODE or DDE?](https://discourse.julialang.org/t/different-loss-function-for-training-ode-or-dde/53347)

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**Author:** [@Qualium](https://discourse.julialang.org/u/Qualium)\
**Replies:** 5\
**Last updated:** [January 20, 2021, 7:05pm UTC](https://discourse.julialang.org/t/different-loss-function-for-training-ode-or-dde/53347 "2021-01-20T19:05:14Z")

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I am learning to use the DiffEqFlux pkg with the tutorial and playing around and I have a weird problem, I cannot figure it out. In the tutorial they train the model adjusting parameters of the lotka-volterra system so b…

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## [Quiver arrows changes style when ploting plot as subplot](https://discourse.julialang.org/t/quiver-arrows-changes-style-when-ploting-plot-as-subplot/53681)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 0\
**Last updated:** [January 20, 2021, 6:01pm UTC](https://discourse.julialang.org/t/quiver-arrows-changes-style-when-ploting-plot-as-subplot/53681 "2021-01-20T18:01:33Z")

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I want to create a couple of plots, and then compile them into a single figure. One of the subplots containing quiver arrows, and they behave weirdly when I do so. The code and figures should demonstrate quite well in th…

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## [ANN: VideoCaptureWrap.jl](https://discourse.julialang.org/t/ann-videocapturewrap-jl/45491)

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**Author:** [@terasakisatoshi](https://discourse.julialang.org/u/terasakisatoshi)\
**Replies:** 10\
**Last updated:** [January 20, 2021, 5:55pm UTC](https://discourse.julialang.org/t/ann-videocapturewrap-jl/45491 "2021-01-20T17:55:21Z")

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Hi there, I’m happy to announce the release of VideoCaptureWrap.jl. :tada: This application gives us an example of how to wrap OpenCV API via CxxWrap.jl. It also demonstrates a demo that capture image from your Web/US…

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