# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=333

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**Page:** 334

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## [How to convert DataFrame into Array{T,2}?](https://discourse.julialang.org/t/how-to-convert-dataframe-into-array-t-2/22487)

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**Author:** [@Eric\_Chen](https://discourse.julialang.org/u/Eric_Chen)\
**Replies:** 7\
**Last updated:** [September 29, 2021, 6:02am UTC](https://discourse.julialang.org/t/how-to-convert-dataframe-into-array-t-2/22487 "2021-09-29T06:02:17Z")

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Let’s say I have a dataframe that only holds number or missings. How can I convert it to a Array{T, 2} ? Without the names / header Thank you using DataFrames df = DataFrame(a=\[ 1, 2, 3, 4, missing\], b= \[1, 2, 3, 4, 5…

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## [Broadcasting Imputed Values](https://discourse.julialang.org/t/broadcasting-imputed-values/68897)

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**Author:** [@WawerOS](https://discourse.julialang.org/u/WawerOS)\
**Replies:** 0\
**Last updated:** [September 29, 2021, 1:10am UTC](https://discourse.julialang.org/t/broadcasting-imputed-values/68897 "2021-09-29T01:10:32Z")

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Hello, I’m new to Turing so this might just be a beginners error but when I try following code using Turing @model function gdemo(x, y) s² ~ InverseGamma(2, 3) m ~ Normal(0, sqrt(s²)) x .~ Normal(m, sqrt(s…

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## [Calling Flux.params() inside gradient changes output?](https://discourse.julialang.org/t/calling-flux-params-inside-gradient-changes-output/68829)

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**Author:** [@AlexLewandowski](https://discourse.julialang.org/u/AlexLewandowski)\
**Replies:** 2\
**Last updated:** [September 28, 2021, 6:32pm UTC](https://discourse.julialang.org/t/calling-flux-params-inside-gradient-changes-output/68829 "2021-09-28T18:32:16Z")

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Could anyone help me understand why calling Flux.params() inside a gradient, changes the gradient? Below is a minimal example where, in get\_grad\_2, I instantiate a variable prowling\_variable = Flux.params(m). The gradie…

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## [Using Flux to construct a CES function](https://discourse.julialang.org/t/using-flux-to-construct-a-ces-function/68842)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 3\
**Last updated:** [September 28, 2021, 4:32pm UTC](https://discourse.julialang.org/t/using-flux-to-construct-a-ces-function/68842 "2021-09-28T16:32:13Z")

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I’m wondering if I Flux.jl can be used to construct a multi layer CES function. I won’t be training the function in Flux, just leverage its multi layer flexibility. For example, consider the function F(x; a, \\rho) = \\l…

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## [Randomness in initialization](https://discourse.julialang.org/t/randomness-in-initialization/68822)

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**Author:** [@joe\_sonic](https://discourse.julialang.org/u/joe_sonic)\
**Replies:** 10\
**Last updated:** [September 28, 2021, 1:20pm UTC](https://discourse.julialang.org/t/randomness-in-initialization/68822 "2021-09-28T13:20:25Z")

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Hi, I have a simple model, which I know there exists multiplicity in results. When I start Ipopt to optimize this model, I found out that every time the optimizer gives me different results. The question is: Is there a …

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## [Return vector when broadcasting over mean vector to generate random numbers](https://discourse.julialang.org/t/return-vector-when-broadcasting-over-mean-vector-to-generate-random-numbers/68851)

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**Author:** [@conorhassan](https://discourse.julialang.org/u/conorhassan)\
**Replies:** 2\
**Last updated:** [September 28, 2021, 7:16am UTC](https://discourse.julialang.org/t/return-vector-when-broadcasting-over-mean-vector-to-generate-random-numbers/68851 "2021-09-28T07:16:39Z")

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Hi there, I am wanting to use something like rand.(Normal.(\[5;10\],1),1) where we have two different mean values \\mu\_1=5, \\mu\_2=10 which we broadcast over to generate 2 random numbers total. I would like the output to …

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## [What does the architecture of Flux.RNN look like?](https://discourse.julialang.org/t/what-does-the-architecture-of-flux-rnn-look-like/44119)

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**Author:** [@XiaodongMa-MRI](https://discourse.julialang.org/u/XiaodongMa-MRI)\
**Replies:** 2\
**Last updated:** [September 27, 2021, 10:06pm UTC](https://discourse.julialang.org/t/what-does-the-architecture-of-flux-rnn-look-like/44119 "2021-09-27T22:06:17Z")

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Hi all, I am confused about the architecture of RNN in Flux.jl. If I define a RNN using the code RNN(3,3), will it be like the left one or the right one in the picture below? Based on the documentation, I think it is…

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## [Arithmetic using binary numbers](https://discourse.julialang.org/t/arithmetic-using-binary-numbers/68823)

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**Author:** [@Jaidy](https://discourse.julialang.org/u/Jaidy)\
**Replies:** 7\
**Last updated:** [September 27, 2021, 10:19pm UTC](https://discourse.julialang.org/t/arithmetic-using-binary-numbers/68823 "2021-09-27T22:19:15Z")

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I have huge matrices each entry of which is a 2-bit binary number. If I were to load them and convert to any of the Floats precisions, the memory required to load will be at least half a terabyte. Can Julia do arithmetic…

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## [Using AbstractEnv from CommonRLInterface with POMDPs](https://discourse.julialang.org/t/using-abstractenv-from-commonrlinterface-with-pomdps/68730)

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**Author:** [@Tyler\_Ingebrand](https://discourse.julialang.org/u/Tyler_Ingebrand)\
**Replies:** 22\
**Last updated:** [September 27, 2021, 9:47pm UTC](https://discourse.julialang.org/t/using-abstractenv-from-commonrlinterface-with-pomdps/68730 "2021-09-27T21:47:06Z")

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Hello. I am trying to use reinforcement learning to solve a simple problem as a proof of concept. I am using DeepQLearning and defining the AbstractEnv(an interface from CommonRLInterface). I am getting the following err…

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## [Problem using JuMP with user-defined function](https://discourse.julialang.org/t/problem-using-jump-with-user-defined-function/68835)

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**Author:** [@vinicius\_de\_lima](https://discourse.julialang.org/u/vinicius_de_lima)\
**Replies:** 1\
**Last updated:** [September 27, 2021, 9:40pm UTC](https://discourse.julialang.org/t/problem-using-jump-with-user-defined-function/68835 "2021-09-27T21:40:48Z")

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I am trying to use JuMP to solve a Non-linear optimization problem, but find a problem using the following code: function Q(H,h\_0,C,D,L) if H \<= h\_0 return 0.0 else Δh = H - h\_0 J = …

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## [Need a combinatorial optimizer for black box function](https://discourse.julialang.org/t/need-a-combinatorial-optimizer-for-black-box-function/68791)

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**Author:** [@PeterSimon](https://discourse.julialang.org/u/PeterSimon)\
**Replies:** 6\
**Last updated:** [September 27, 2021, 1:34pm UTC](https://discourse.julialang.org/t/need-a-combinatorial-optimizer-for-black-box-function/68791 "2021-09-27T13:34:03Z")

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I’m looking for a combinatorial optimizer (decision variables are a permutation of the integers 1, 2, \\ldots, N, where N is between, say, 50, and 500, for a black box function (i.e., only the value of the objective funct…

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## [Has anyone used julia to work with the Notion api?](https://discourse.julialang.org/t/has-anyone-used-julia-to-work-with-the-notion-api/68741)

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**Author:** [@development\_mentor](https://discourse.julialang.org/u/development_mentor)\
**Replies:** 1\
**Last updated:** [September 27, 2021, 10:59am UTC](https://discourse.julialang.org/t/has-anyone-used-julia-to-work-with-the-notion-api/68741 "2021-09-27T10:59:11Z")

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I want to use Julia to build a notion API in order to create some custom functions that aren’t originally in notion. I’m new to APIs and don’t know if it’s possible to use an API with any language.

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## [Get post attributes in Franklin](https://discourse.julialang.org/t/get-post-attributes-in-franklin/68430)

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**Author:** [@garrek](https://discourse.julialang.org/u/garrek)\
**Replies:** 12\
**Last updated:** [September 27, 2021, 1:49am UTC](https://discourse.julialang.org/t/get-post-attributes-in-franklin/68430 "2021-09-27T01:49:33Z")

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I’m in the process of migrating from Jekyll to Franklin for my static website (Garrek.org) hosted on GitHub. (In the near future, I will have LaTeX and plots and things, which Franklin seems to excel at). Jekyll has some…

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## [How to specify algorithm-specific parameters in NLopt.jl?](https://discourse.julialang.org/t/how-to-specify-algorithm-specific-parameters-in-nlopt-jl/68765)

<div class="topic-metadata">

**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 7\
**Last updated:** [September 27, 2021, 1:44am UTC](https://discourse.julialang.org/t/how-to-specify-algorithm-specific-parameters-in-nlopt-jl/68765 "2021-09-27T01:44:47Z")

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The General Reference of NLopt here describes how to specify algorithm-specific parameters, but the NLopt.jl documentation does not have that section. Is it possible to access those parameters from NLopt.jl?

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## [How to modify a JSON object that's been read in?](https://discourse.julialang.org/t/how-to-modify-a-json-object-thats-been-read-in/68775)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 2\
**Last updated:** [September 27, 2021, 1:04am UTC](https://discourse.julialang.org/t/how-to-modify-a-json-object-thats-been-read-in/68775 "2021-09-27T01:04:45Z")

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I have read a JSON using JSON3.jl but after that I can’t seem to modify the json. E.g. a = JSON3.read("{\\"a\\":1}") a\[:b\] = 2 what I get is this. Is there an easy to mutate the object? LoadError: MethodError: no met…

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## [Reading string including Greek letters from SQL server](https://discourse.julialang.org/t/reading-string-including-greek-letters-from-sql-server/68682)

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**Author:** [@mobar](https://discourse.julialang.org/u/mobar)\
**Replies:** 2\
**Last updated:** [September 26, 2021, 7:40pm UTC](https://discourse.julialang.org/t/reading-string-including-greek-letters-from-sql-server/68682 "2021-09-26T19:40:57Z")

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I need to store serialized JSON strings of types that include Greek letters (such as λ) on an sql server table. Storing works just fine (field defined as nvarchar(max) data type) and sql prefixed with N) - but I’m havin…

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## [Linnea: automatic generation of efficient linear algebra programs](https://discourse.julialang.org/t/linnea-automatic-generation-of-efficient-linear-algebra-programs/66288)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 13\
**Last updated:** [September 26, 2021, 5:39pm UTC](https://discourse.julialang.org/t/linnea-automatic-generation-of-efficient-linear-algebra-programs/66288 "2021-09-26T17:39:21Z")

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Came across this interesting article about Linnea and would like to share it. The authors claim that the code Linnea generates almost always outperforms the recommended implementations in Matlab, Julia, Eigen and Armadi…

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## [How mature is GalacticOptim for use NLopt algorithms](https://discourse.julialang.org/t/how-mature-is-galacticoptim-for-use-nlopt-algorithms/68764)

<div class="topic-metadata">

**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [September 26, 2021, 12:11pm UTC](https://discourse.julialang.org/t/how-mature-is-galacticoptim-for-use-nlopt-algorithms/68764 "2021-09-26T12:11:30Z")

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GalacticOptim has very convenient features like automatically constructing gradients, etc. but I am worried about its maturity given the thin documentation. Am I better off just using the NLopt.jl API directly?

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## [Compressed Sensing using StructuredOptimization.jl](https://discourse.julialang.org/t/compressed-sensing-using-structuredoptimization-jl/35098)

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**Author:** [@lstagner](https://discourse.julialang.org/u/lstagner)\
**Replies:** 12\
**Last updated:** [September 26, 2021, 11:35am UTC](https://discourse.julialang.org/t/compressed-sensing-using-structuredoptimization-jl/35098 "2021-09-26T11:35:59Z")

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Here is something cool I did: gist using LinearAlgebra using Random using FFTW using PyPlot using StructuredOptimization N = 256 P = 5 K = 32 # Pick out P random frequencies freq = randperm(Int(N/2)).-1 freq = freq\[1:…

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## [Rs Dmnorm equivalent in Julia](https://discourse.julialang.org/t/rs-dmnorm-equivalent-in-julia/68773)

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**Author:** [@djholiver](https://discourse.julialang.org/u/djholiver)\
**Replies:** 2\
**Last updated:** [September 26, 2021, 11:08am UTC](https://discourse.julialang.org/t/rs-dmnorm-equivalent-in-julia/68773 "2021-09-26T11:08:08Z")

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Hi, I am very new to statistical computing but have a need to convert an R script to Julia to mitigate high memory usage and performance challenges. I have been able to clean up quite a bit so far but the below is a sti…

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## [Not able to load PostgreSQL into LibPQ.jl](https://discourse.julialang.org/t/not-able-to-load-postgresql-into-libpq-jl/68767)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 20\
**Last updated:** [September 26, 2021, 3:45am UTC](https://discourse.julialang.org/t/not-able-to-load-postgresql-into-libpq-jl/68767 "2021-09-26T03:45:21Z")

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I have installed postgressql, and am trying to use the LibPQ.jl . But, when I try to connect conn = LibPQ.Connection("dbname=postgres user=BrettKnoss) I’m told that. conn= could not connect to server: No such file or…

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## [Notebook on particle simulations](https://discourse.julialang.org/t/notebook-on-particle-simulations/68496)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 27\
**Last updated:** [September 25, 2021, 8:37pm UTC](https://discourse.julialang.org/t/notebook-on-particle-simulations/68496 "2021-09-25T20:37:37Z")

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I have written a notebook on particle simulations using Julia, to be presented at the FortranCon this week: https://m3g.github.io/2021\_FortranCon/ (https://github.com/m3g/2021\_FortranCon) It may be interesting for stu…

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## [How to align x axis in GR](https://discourse.julialang.org/t/how-to-align-x-axis-in-gr/68626)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 2\
**Last updated:** [September 25, 2021, 6:11pm UTC](https://discourse.julialang.org/t/how-to-align-x-axis-in-gr/68626 "2021-09-25T18:11:55Z")

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How to align the axis? p1 = Plots.plot(rand(10), label="A very loooooooooooooooong label") p2 = Plots.plot(rand(10), label="A short label") Plots.plot(p1, p2, layout=(2,1), legend=:outerright)

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## [Solving chemical systems of equations with both equilibrium and kinetic species](https://discourse.julialang.org/t/solving-chemical-systems-of-equations-with-both-equilibrium-and-kinetic-species/68755)

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**Author:** [@gagnonaa10](https://discourse.julialang.org/u/gagnonaa10)\
**Replies:** 1\
**Last updated:** [September 25, 2021, 5:52pm UTC](https://discourse.julialang.org/t/solving-chemical-systems-of-equations-with-both-equilibrium-and-kinetic-species/68755 "2021-09-25T17:52:41Z")

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This is building on a different discourse post I made previously: https://discourse.julialang.org/t/constraints-in-catalyst-jl-for-weak-acids-and-ph-equilibrium/68037/2 And on Github: https://github.com/SciML/Catalyst…

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## [How to use btn\_\_toggle in Stipple](https://discourse.julialang.org/t/how-to-use-btn-toggle-in-stipple/56501)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 6\
**Last updated:** [March 4, 2021, 11:46pm UTC](https://discourse.julialang.org/t/how-to-use-btn-toggle-in-stipple/56501 "2021-03-04T23:46:20Z")

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Hi and thank you @hhaensel :smiley: How can I use btn\_\_toggle in Stipple? I think my struggle is the options property. I can’t get it to work no matter what syntax I use (copy-paste the JS from the example, vector of na…

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## [How to pass optimizer options to GalacticOptim?](https://discourse.julialang.org/t/how-to-pass-optimizer-options-to-galacticoptim/68742)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 1\
**Last updated:** [September 25, 2021, 10:35am UTC](https://discourse.julialang.org/t/how-to-pass-optimizer-options-to-galacticoptim/68742 "2021-09-25T10:35:45Z")

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I’m trying to play with GalacticOptim. How can I pass options to the optimizer? In plain Optim, I can pass options like store\_trace with Optim.Options(store\_trace=true). How can I pass those options in the example below? …

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## [Anyone experimented with Jetson Nano's?](https://discourse.julialang.org/t/anyone-experimented-with-jetson-nanos/68738)

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**Author:** [@skypuppy](https://discourse.julialang.org/u/skypuppy)\
**Replies:** 2\
**Last updated:** [September 25, 2021, 10:10am UTC](https://discourse.julialang.org/t/anyone-experimented-with-jetson-nanos/68738 "2021-09-25T10:10:12Z")

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Before I buy half a dozen more Nano’s :slight\_smile: has anyone tested Julia with the GPU’s on the Nano’s? Or Xaviers?

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## [MultiJuMP.jl - linear models](https://discourse.julialang.org/t/multijump-jl-linear-models/68695)

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**Author:** [@s154428](https://discourse.julialang.org/u/s154428)\
**Replies:** 4\
**Last updated:** [September 25, 2021, 5:17am UTC](https://discourse.julialang.org/t/multijump-jl-linear-models/68695 "2021-09-25T05:17:36Z")

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Hi I’m solving a multi objective MILP with two objectives and I’m using the package MultiJuMP.jl. When solving linear models the are two methods in MultiJuMP a WeightedSum and EpsilonCons. Why should I not provide the…

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## [Hyperbolic Deep Learning](https://discourse.julialang.org/t/hyperbolic-deep-learning/45895)

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**Author:** [@tbreloff](https://discourse.julialang.org/u/tbreloff)\
**Replies:** 4\
**Last updated:** [September 25, 2021, 12:26am UTC](https://discourse.julialang.org/t/hyperbolic-deep-learning/45895 "2021-09-25T00:26:31Z")

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Are there any active communities working in the space of hyperbolic deep learning? I’m specifically interested in Flux-compatible libraries which define the basic DL operations for either the Poincare or Lorentz hyperbol…

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## [How to ignore 1 of the 2 GPUs on my machine](https://discourse.julialang.org/t/how-to-ignore-1-of-the-2-gpus-on-my-machine/68697)

<div class="topic-metadata">

**Author:** [@JosePereiraUA](https://discourse.julialang.org/u/JosePereiraUA)\
**Replies:** 7\
**Last updated:** [September 24, 2021, 4:05pm UTC](https://discourse.julialang.org/t/how-to-ignore-1-of-the-2-gpus-on-my-machine/68697 "2021-09-24T16:05:39Z")

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I’m trying to run a piece of code on a different machine than it was written on. On this new machine, there are two GPUs: a Teska K40c and an NVIDIA GeForce GTX 650. The problem seems to be with the second one. Running \]…

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