# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=198

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**Page:** 199

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## [Simulating a dynamic satellite constellation network using SatelliteToolbox.jl](https://discourse.julialang.org/t/simulating-a-dynamic-satellite-constellation-network-using-satellitetoolbox-jl/97979)

<div class="topic-metadata">

**Author:** [@rafiulnakib](https://discourse.julialang.org/u/rafiulnakib)\
**Replies:** 1\
**Last updated:** [April 27, 2023, 6:20am UTC](https://discourse.julialang.org/t/simulating-a-dynamic-satellite-constellation-network-using-satellitetoolbox-jl/97979 "2023-04-27T06:20:43Z")

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Hi everyone, I am trying to simulate a dynamic satellite constellation network using SatelliteToolbox. The goal is to use this network and integrate it with the QuNet package for benchmarking and performance analysis as…

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## [Tagging values unique to a group in a dataframe](https://discourse.julialang.org/t/tagging-values-unique-to-a-group-in-a-dataframe/97967)

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**Author:** [@George9000](https://discourse.julialang.org/u/George9000)\
**Replies:** 2\
**Last updated:** [April 27, 2023, 1:59am UTC](https://discourse.julialang.org/t/tagging-values-unique-to-a-group-in-a-dataframe/97967 "2023-04-27T01:59:12Z")

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Say that I have a dataframe: function exampl() grp = Int8\[\] for i in 1:5 grp = append!(grp, fill(i, 7)) end values = Int8\[\] for i in 1:7 values = append!(values, rand(1:15, 5)) e…

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## [Naming constraints error](https://discourse.julialang.org/t/naming-constraints-error/97959)

<div class="topic-metadata">

**Author:** [@irene\_ub](https://discourse.julialang.org/u/irene_ub)\
**Replies:** 1\
**Last updated:** [April 26, 2023, 10:57pm UTC](https://discourse.julialang.org/t/naming-constraints-error/97959 "2023-04-26T22:57:36Z")

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Hello, I have an optimization model, for which I’m trying to give names to its constraints so that I can write them to an lp file and find them easily. However, I’m having some trouble. The constraint specifically that…

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## [COUENNE with Julia](https://discourse.julialang.org/t/couenne-with-julia/43216)

<div class="topic-metadata">

**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 47\
**Last updated:** [April 26, 2023, 10:43pm UTC](https://discourse.julialang.org/t/couenne-with-julia/43216 "2023-04-26T22:43:40Z")

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hello there, I am trying to install and use Couenne on Windows 10 so I can use it in my Julia program, Does anyone has experience with installing solvers. It is my first time to do something like that. What I understand…

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## [Optimizing performance with FASTX I/O stream and Codon Counting](https://discourse.julialang.org/t/optimizing-performance-with-fastx-i-o-stream-and-codon-counting/97918)

<div class="topic-metadata">

**Author:** [@gus-pendleton](https://discourse.julialang.org/u/gus-pendleton)\
**Replies:** 5\
**Last updated:** [April 26, 2023, 8:05pm UTC](https://discourse.julialang.org/t/optimizing-performance-with-fastx-i-o-stream-and-codon-counting/97918 "2023-04-26T20:05:38Z")

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Hello, I am working to write code for codon usage bias, and my slowest step by far is calculating counts of individual codons for each gene in a fasta sequence of a genome. The general idea is that I’m using FASTX to s…

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## [Pre-allocating arrays for parallel multiple shooting Neural ODE training in Flux](https://discourse.julialang.org/t/pre-allocating-arrays-for-parallel-multiple-shooting-neural-ode-training-in-flux/97867)

<div class="topic-metadata">

**Author:** [@linkz](https://discourse.julialang.org/u/linkz)\
**Replies:** 1\
**Last updated:** [April 24, 2023, 5:30pm UTC](https://discourse.julialang.org/t/pre-allocating-arrays-for-parallel-multiple-shooting-neural-ode-training-in-flux/97867 "2023-04-24T17:30:39Z")

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Hi, I would like to pre-allocate an array of matrices which I would then in-place mutate in my multiple shooting training in Flux, optimized via Optimization (see skeleton code below). However, I don’t know what type sho…

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## [Sum rows of DataFrame](https://discourse.julialang.org/t/sum-rows-of-dataframe/97920)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 6\
**Last updated:** [April 26, 2023, 3:44pm UTC](https://discourse.julialang.org/t/sum-rows-of-dataframe/97920 "2023-04-26T15:44:41Z")

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What is the most idiomatic way to sum up all rows of a DataFrame into a row of totals? Can you give an example where the DataFrame contains numeric and non-numeric columns?

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## [Loading Dataframes into Big Query](https://discourse.julialang.org/t/loading-dataframes-into-big-query/95457)

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**Author:** [@AntonoK](https://discourse.julialang.org/u/AntonoK)\
**Replies:** 17\
**Last updated:** [April 26, 2023, 1:36pm UTC](https://discourse.julialang.org/t/loading-dataframes-into-big-query/95457 "2023-04-26T13:36:08Z")

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I’m currently exploring the best way to directly load a dataframe object into Google’s BigQuery, similar to Pandas to\_gbq function. As a hotfix, I’ve been looking at a command line wrapper. This would line up with the p…

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## [Missing functions in namespace from BioSequences](https://discourse.julialang.org/t/missing-functions-in-namespace-from-biosequences/97871)

<div class="topic-metadata">

**Author:** [@gus-pendleton](https://discourse.julialang.org/u/gus-pendleton)\
**Replies:** 4\
**Last updated:** [April 26, 2023, 4:40am UTC](https://discourse.julialang.org/t/missing-functions-in-namespace-from-biosequences/97871 "2023-04-26T04:40:37Z")

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I feel like I’m missing something fundamental, but I’m unable to follow many of the examples in the BioSequences documentation, because many of the functions they use remain undefined in my namespace. A few key ones that…

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## [KernelAbstractions.get\_backend keyword arguments](https://discourse.julialang.org/t/kernelabstractions-get-backend-keyword-arguments/97895)

<div class="topic-metadata">

**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 1\
**Last updated:** [April 26, 2023, 2:36am UTC](https://discourse.julialang.org/t/kernelabstractions-get-backend-keyword-arguments/97895 "2023-04-26T02:36:23Z")

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CUDABackend accepts two keyword arguments. the default for prefer\_blocks is false. i have a custom kernel for which i need that to be true. KernelAbstractions.get\_backend has no way to pass that in. so how do i write …

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## [Compressed svd algorithm implementation](https://discourse.julialang.org/t/compressed-svd-algorithm-implementation/97837)

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**Author:** [@Desmond](https://discourse.julialang.org/u/Desmond)\
**Replies:** 4\
**Last updated:** [April 25, 2023, 11:34pm UTC](https://discourse.julialang.org/t/compressed-svd-algorithm-implementation/97837 "2023-04-25T23:34:32Z")

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I am trying to implement the compressed SVD in this \[https://openaccess.thecvf.com/content\_ICCV\_2017\_workshops/papers/w25/Erichson\_Compressed\_Singular\_Value\_ICCV\_2017\_paper.pdf\]. Attached is the algorithm. I have proble…

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## [How to change all desion variables from binary to non-negative and vice versa?](https://discourse.julialang.org/t/how-to-change-all-desion-variables-from-binary-to-non-negative-and-vice-versa/97893)

<div class="topic-metadata">

**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 1\
**Last updated:** [April 25, 2023, 3:43pm UTC](https://discourse.julialang.org/t/how-to-change-all-desion-variables-from-binary-to-non-negative-and-vice-versa/97893 "2023-04-25T15:43:26Z")

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Is it possible to define a model via cplex where all the variables are binary like @variable(model, a, Bin), and run this model, then without any manual modification change all varaibles to nonnegative and run it again? …

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## [Cannot read file written by Arrow.jl in Python](https://discourse.julialang.org/t/cannot-read-file-written-by-arrow-jl-in-python/97889)

<div class="topic-metadata">

**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 3\
**Last updated:** [April 25, 2023, 12:36pm UTC](https://discourse.julialang.org/t/cannot-read-file-written-by-arrow-jl-in-python/97889 "2023-04-25T12:36:55Z")

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I’m using a Julia environment with Arrow v2.5.2 and DataFrames v1.5.1, and Python 3.10.2 with pandas 1.5.0 and pyarrow 11.0.0. From the User manual I think I could do: using Arrow, DataFrames m = rand(20,10) open("exa…

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## [Estimating some parameters of DDEs with callbacks](https://discourse.julialang.org/t/estimating-some-parameters-of-ddes-with-callbacks/97614)

<div class="topic-metadata">

**Author:** [@pascal](https://discourse.julialang.org/u/pascal)\
**Replies:** 13\
**Last updated:** [April 25, 2023, 12:00pm UTC](https://discourse.julialang.org/t/estimating-some-parameters-of-ddes-with-callbacks/97614 "2023-04-25T12:00:28Z")

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Hi, I have a delay differential equation model with 3 model parameters and a drug perturbation with one parameter (alpha). I’ve set up the simulation as: using DifferentialEquations using DataFrames, DataFramesMeta usi…

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## [Create legend for dodge boxplot in Makie](https://discourse.julialang.org/t/create-legend-for-dodge-boxplot-in-makie/97824)

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**Author:** [@vembha](https://discourse.julialang.org/u/vembha)\
**Replies:** 2\
**Last updated:** [April 25, 2023, 11:05am UTC](https://discourse.julialang.org/t/create-legend-for-dodge-boxplot-in-makie/97824 "2023-04-25T11:05:21Z")

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Hello, I am trying to get a legend for a box plot created in Makie. For the example provided in the website Page Redirection (attached is the box plot), how to get a legend inside the figure panel? Like in a scatter plo…

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## [Split a large image into many small images to get training data for a CNN](https://discourse.julialang.org/t/split-a-large-image-into-many-small-images-to-get-training-data-for-a-cnn/97853)

<div class="topic-metadata">

**Author:** [@Kemper](https://discourse.julialang.org/u/Kemper)\
**Replies:** 2\
**Last updated:** [April 25, 2023, 9:12am UTC](https://discourse.julialang.org/t/split-a-large-image-into-many-small-images-to-get-training-data-for-a-cnn/97853 "2023-04-25T09:12:15Z")

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Hey, I Googled, but I think I miss the right terms to find what I am looking for: I want to train a CNN to dedect landforms. I have a .shp file with the landforms for training and want to: a: rasterize it b: split u…

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## [Using DiffEqBase.NLSolveTerminationCondition in NonlinearSolve.jl](https://discourse.julialang.org/t/using-diffeqbase-nlsolveterminationcondition-in-nonlinearsolve-jl/97873)

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**Author:** [@psterzinger](https://discourse.julialang.org/u/psterzinger)\
**Replies:** 4\
**Last updated:** [April 25, 2023, 7:10am UTC](https://discourse.julialang.org/t/using-diffeqbase-nlsolveterminationcondition-in-nonlinearsolve-jl/97873 "2023-04-25T07:10:16Z")

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I am trying to solve a system of three nonlinear equations and would like to use the termination conditions provided by DiffEqBase.NLSolveTerminationCondition (see the documentation of NonlinearSolve.jl. The function de…

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## [Help with setting up a JuMP model to give an even 'spread' of samples](https://discourse.julialang.org/t/help-with-setting-up-a-jump-model-to-give-an-even-spread-of-samples/97718)

<div class="topic-metadata">

**Author:** [@sdwfrost](https://discourse.julialang.org/u/sdwfrost)\
**Replies:** 3\
**Last updated:** [April 25, 2023, 1:05am UTC](https://discourse.julialang.org/t/help-with-setting-up-a-jump-model-to-give-an-even-spread-of-samples/97718 "2023-04-25T01:05:42Z")

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Hi everyone, I’m trying to learn optimization alongside JuMP syntax, and as a toy problem, I’m trying an integer based problem, in which I have a variable y, with decision variables x (in \[0,1\]), and I want to be able t…

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## [Cdf of multivariate normal in distributions.jl](https://discourse.julialang.org/t/cdf-of-multivariate-normal-in-distributions-jl/4773)

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**Author:** [@newb\_gk](https://discourse.julialang.org/u/newb_gk)\
**Replies:** 24\
**Last updated:** [April 24, 2023, 8:27am UTC](https://discourse.julialang.org/t/cdf-of-multivariate-normal-in-distributions-jl/4773 "2023-04-24T08:27:22Z")

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I’m trying to use the cdf of a multivariate normal distribution using Distributions.jl. While d = Normal(0,1) d2 = MvNormal(\[0.;0.\], \[1. 0.;0. 1.\]) x = \[1. ; 2.\] e1 = cdf(d,x\[1\]) e2 = cdf(d,x\[2\]) works (as long as the…

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## [Saving/loading Flux models with Julia 1.8.x?](https://discourse.julialang.org/t/saving-loading-flux-models-with-julia-1-8-x/89275)

<div class="topic-metadata">

**Author:** [@mcreel](https://discourse.julialang.org/u/mcreel)\
**Replies:** 6\
**Last updated:** [April 24, 2023, 8:20pm UTC](https://discourse.julialang.org/t/saving-loading-flux-models-with-julia-1-8-x/89275 "2023-04-24T20:20:16Z")

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I have been using BSON.jl for saving and loading Flux models, but with Julia 1.8, there is an issue with BSON that appears to be a sticking point (\`setfield!: const field .names of type TypeName cannot be changed\` on Jul…

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## [FLUX.JL -- MethodError: no method matching loss()](https://discourse.julialang.org/t/flux-jl-methoderror-no-method-matching-loss/63478)

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**Author:** [@BroccoliFever](https://discourse.julialang.org/u/BroccoliFever)\
**Replies:** 4\
**Last updated:** [April 24, 2023, 6:32pm UTC](https://discourse.julialang.org/t/flux-jl-methoderror-no-method-matching-loss/63478 "2023-04-24T18:32:20Z")

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I have trained CNNs using PyTorch, and I am trying to run a train loop on a simple CNN in Flux for binary (cat/dog) classification, but I cannot for the life of me figure out how to get the loss functions to work in Flux…

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## [What is the status of pretrained standard models (for machine learning) in the Julia ecosystem?](https://discourse.julialang.org/t/what-is-the-status-of-pretrained-standard-models-for-machine-learning-in-the-julia-ecosystem/97702)

<div class="topic-metadata">

**Author:** [@Euhan](https://discourse.julialang.org/u/Euhan)\
**Replies:** 5\
**Last updated:** [April 24, 2023, 6:23pm UTC](https://discourse.julialang.org/t/what-is-the-status-of-pretrained-standard-models-for-machine-learning-in-the-julia-ecosystem/97702 "2023-04-24T18:23:20Z")

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I have previously tried using Metalhead to take advantage of standard nets, but I haven’t been able to use anything with pretrained weights. Or rather, at the time none of the models I looked at, had weights. What is th…

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## [Status of Dash.jl](https://discourse.julialang.org/t/status-of-dash-jl/97806)

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**Author:** [@JesperMartinsson](https://discourse.julialang.org/u/JesperMartinsson)\
**Replies:** 3\
**Last updated:** [April 24, 2023, 2:54pm UTC](https://discourse.julialang.org/t/status-of-dash-jl/97806 "2023-04-24T14:54:25Z")

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Anyone knows the status of Dash.jl compared to the python version of it? The docs on the website often refer to python. Does Dash.jl only contain a subset of the python implementation or are the docs for the julia versio…

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## [Invert a row selection in DataFramesMeta](https://discourse.julialang.org/t/invert-a-row-selection-in-dataframesmeta/97792)

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**Author:** [@ForestRaven](https://discourse.julialang.org/u/ForestRaven)\
**Replies:** 3\
**Last updated:** [April 24, 2023, 2:22pm UTC](https://discourse.julialang.org/t/invert-a-row-selection-in-dataframesmeta/97792 "2023-04-24T14:22:50Z")

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Hi, Is there a better way to write this operation: @rsubset d !occursin("julia", :language) I would like to use @subset but do not know how to compose it with the negation. Thanks !

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## [GLMakie & Observables with GeometryBasis or user defined types](https://discourse.julialang.org/t/glmakie-observables-with-geometrybasis-or-user-defined-types/97851)

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**Author:** [@mpirke](https://discourse.julialang.org/u/mpirke)\
**Replies:** 2\
**Last updated:** [April 24, 2023, 11:55am UTC](https://discourse.julialang.org/t/glmakie-observables-with-geometrybasis-or-user-defined-types/97851 "2023-04-24T11:55:43Z")

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Hey out there! I have a question concerning Makie and the use of Observables. Here’s what I liked to do: using GLMakie, GeometryBasics mutable struct foo{T} x::Vector{T} r::T end function makefig(foo::foo) …

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## [CSV.jl fails when reading multiple inputs at once if variable name "name" occurs](https://discourse.julialang.org/t/csv-jl-fails-when-reading-multiple-inputs-at-once-if-variable-name-name-occurs/97610)

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**Author:** [@klwlevy](https://discourse.julialang.org/u/klwlevy)\
**Replies:** 7\
**Last updated:** [April 24, 2023, 9:17am UTC](https://discourse.julialang.org/t/csv-jl-fails-when-reading-multiple-inputs-at-once-if-variable-name-name-occurs/97610 "2023-04-24T09:17:42Z")

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Hi there, I am importing multiple csv files using the excellent CSV.jl package. However, I fail to import all files in one go when one of the imported variables has the variable name “name”. Is this a bug, and can some…

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## [DataFrames.jl: metadata](https://discourse.julialang.org/t/dataframes-jl-metadata/84544)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 148\
**Last updated:** [April 24, 2023, 9:01am UTC](https://discourse.julialang.org/t/dataframes-jl-metadata/84544 "2023-04-24T09:01:37Z")

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The discussion on metadata in DataFrames.jl has started 10 years ago, see this issue. In DataFrames.jl we decided to finally settle the issue. The relevant PR is here. The fact that metadata issue has been open for 10 …

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## [Is there a allocation free graph package?](https://discourse.julialang.org/t/is-there-a-allocation-free-graph-package/97327)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 8\
**Last updated:** [April 24, 2023, 7:07am UTC](https://discourse.julialang.org/t/is-there-a-allocation-free-graph-package/97327 "2023-04-24T07:07:28Z")

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I’m dealing with graphs that have a maximal adjacency count. In that setting, it is possible to add, iterate and remove edges without allocations (see implementation below). That is important since I need to do these ope…

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## [Dead links in Flux.jl's CONTRIBUTING.md](https://discourse.julialang.org/t/dead-links-in-flux-jls-contributing-md/97819)

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**Author:** [@trung](https://discourse.julialang.org/u/trung)\
**Replies:** 5\
**Last updated:** [April 23, 2023, 9:33pm UTC](https://discourse.julialang.org/t/dead-links-in-flux-jls-contributing-md/97819 "2023-04-23T21:33:00Z")

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I’ve been reading through Flux.jl’s CONTRIBUTING.md and there are two dead links under the Learn Flux section: Flux’s official Getting Started tutorial Deep Learning with Flux - A 60 Minute Blitz: a quick intro to Flu…

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## [Nonlinear objective with both splatted variable and vector parameters](https://discourse.julialang.org/t/nonlinear-objective-with-both-splatted-variable-and-vector-parameters/97791)

<div class="topic-metadata">

**Author:** [@franckgaga](https://discourse.julialang.org/u/franckgaga)\
**Replies:** 7\
**Last updated:** [April 23, 2023, 7:43pm UTC](https://discourse.julialang.org/t/nonlinear-objective-with-both-splatted-variable-and-vector-parameters/97791 "2023-04-23T19:43:57Z")

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Hi, I’m currently writing a model predictive control package. The JuMP package is really helpful, thanks for everything. For nonlinear programming, my decision variable is a vector so I need to rely on the splatting sy…

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