# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=322

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**Page:** 323

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## [Making the result of \`nullspace\` sparse](https://discourse.julialang.org/t/making-the-result-of-nullspace-sparse/71310)

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**Author:** [@jchen975](https://discourse.julialang.org/u/jchen975)\
**Replies:** 1\
**Last updated:** [November 12, 2021, 12:22pm UTC](https://discourse.julialang.org/t/making-the-result-of-nullspace-sparse/71310 "2021-11-12T12:22:07Z")

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Is it possible to make the result of LinearAlgebra.nullspace as sparse as possible? How about when using the package Nemo for sparse matrices over \\mathbb{R}? Regardless of whether or not this is possible, what would be…

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## [How to find crossing point using Spline1D in julia?](https://discourse.julialang.org/t/how-to-find-crossing-point-using-spline1d-in-julia/71364)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 2\
**Last updated:** [November 12, 2021, 9:38am UTC](https://discourse.julialang.org/t/how-to-find-crossing-point-using-spline1d-in-julia/71364 "2021-11-12T09:38:08Z")

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I have fitted a spline function using Spline1D from the package Dierckx to the data: x = \[0.0, 0.25167322597331027, 1.6518531853618088, 4.032506892599284, 6.871304792339401, 10.090447889235595, 13.686254426579751, 17.61…

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## [Multicollinearity and GLM](https://discourse.julialang.org/t/multicollinearity-and-glm/71340)

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**Author:** [@rikh](https://discourse.julialang.org/u/rikh)\
**Replies:** 5\
**Last updated:** [November 11, 2021, 9:29pm UTC](https://discourse.julialang.org/t/multicollinearity-and-glm/71340 "2021-11-11T21:29:44Z")

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Below, I show some generated data for a linear regression. With these features (also known as variables, covariates or predictors) A, B, C, D and E, I aim to predict an outcome Y. Would the data shown below be considered…

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## [CuArray only supports element types that are stored inline?](https://discourse.julialang.org/t/cuarray-only-supports-element-types-that-are-stored-inline/71339)

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**Author:** [@Ludovic\_Dumoulin](https://discourse.julialang.org/u/Ludovic_Dumoulin)\
**Replies:** 1\
**Last updated:** [November 11, 2021, 5:23pm UTC](https://discourse.julialang.org/t/cuarray-only-supports-element-types-that-are-stored-inline/71339 "2021-11-11T17:23:19Z")

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Hello, I would like to define, a mutable structure with a field of type ::CuArray{an\_other\_mutable\_structure} but I get this error: CuArray only supports element types that are stored inline I don’t understand what i…

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## [Find all Hamiltonian cycles using Graphs.jl](https://discourse.julialang.org/t/find-all-hamiltonian-cycles-using-graphs-jl/71304)

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**Author:** [@mdtisdall](https://discourse.julialang.org/u/mdtisdall)\
**Replies:** 3\
**Last updated:** [November 11, 2021, 3:42pm UTC](https://discourse.julialang.org/t/find-all-hamiltonian-cycles-using-graphs-jl/71304 "2021-11-11T15:42:20Z")

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I’m wondering if there’s an existing implementation of an algorithm to find all Hamiltonian cycles within an unweighted, undirected graph. The graphs I’m interested in are small, on the order of 20 vertices. Basically I’…

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## [Plotting in phase space with Makie.jl](https://discourse.julialang.org/t/plotting-in-phase-space-with-makie-jl/70652)

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**Author:** [@baumer](https://discourse.julialang.org/u/baumer)\
**Replies:** 3\
**Last updated:** [November 11, 2021, 2:05pm UTC](https://discourse.julialang.org/t/plotting-in-phase-space-with-makie-jl/70652 "2021-11-11T14:05:46Z")

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I have an 10-element Vector{Array{Float64, 6}}: that gives the solution to a 6D + time PDE at every point in phase space on a certain interval as it progress through 10 time steps (hence the 10-element vector). I want t…

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## [Learning statistics: seeking advice on how to model a 2d-size distribution of clothing items](https://discourse.julialang.org/t/learning-statistics-seeking-advice-on-how-to-model-a-2d-size-distribution-of-clothing-items/71152)

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**Author:** [@tim\_pi](https://discourse.julialang.org/u/tim_pi)\
**Replies:** 25\
**Last updated:** [November 11, 2021, 1:47pm UTC](https://discourse.julialang.org/t/learning-statistics-seeking-advice-on-how-to-model-a-2d-size-distribution-of-clothing-items/71152 "2021-11-11T13:47:13Z")

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Hi everyone, I’m new to Julia and have been trying it out for the past few weeks. As I’m still only beginning to (re)learn statistics as well, I’ve set out to get some insight into the following problem (I didn’t want t…

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## [Turing: help speed up state space model](https://discourse.julialang.org/t/turing-help-speed-up-state-space-model/64234)

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**Author:** [@Stephen\_Wild](https://discourse.julialang.org/u/Stephen_Wild)\
**Replies:** 3\
**Last updated:** [November 11, 2021, 1:03pm UTC](https://discourse.julialang.org/t/turing-help-speed-up-state-space-model/64234 "2021-11-11T13:03:27Z")

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Hello all. I am trying to use Turing to run a state space model based on Simon Jackman’s Bayesian Analysis for the Social Sciences. In chapter 9, he sets out a few different latent variable models, including a state spa…

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## [How to custom noise](https://discourse.julialang.org/t/how-to-custom-noise/71280)

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**Author:** [@Frazze](https://discourse.julialang.org/u/Frazze)\
**Replies:** 6\
**Last updated:** [November 11, 2021, 12:20pm UTC](https://discourse.julialang.org/t/how-to-custom-noise/71280 "2021-11-11T12:20:32Z")

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Hi everyone, I would like to study a SDE Problem with just additive white gaussian noise, but I would like also to control the value of the variance just to see what happen varying this value. How can I do? How can bui…

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## [Error from MLJ Iris example, no method matching?](https://discourse.julialang.org/t/error-from-mlj-iris-example-no-method-matching/71313)

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**Author:** [@jamaas](https://discourse.julialang.org/u/jamaas)\
**Replies:** 4\
**Last updated:** [November 11, 2021, 10:02am UTC](https://discourse.julialang.org/t/error-from-mlj-iris-example-no-method-matching/71313 "2021-11-11T10:02:14Z")

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I’m at the install/testing phase of Julia and attempting to run the Iris example of training a model using the Julia MLJ. I think I have it installed properly but am getting this error. What have I done incorrectly? Thx.…

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## [Plotting with Observables in Makie](https://discourse.julialang.org/t/plotting-with-observables-in-makie/70939)

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**Author:** [@jm4h](https://discourse.julialang.org/u/jm4h)\
**Replies:** 6\
**Last updated:** [November 11, 2021, 6:49am UTC](https://discourse.julialang.org/t/plotting-with-observables-in-makie/70939 "2021-11-11T06:49:10Z")

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I want to make an interactive plot with sliders, where the displayed data changes when my sliders get moved. That seems to work when the observable plotted is an array of positions. But is it possible if the observable …

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## [CTESN Code / Packages?](https://discourse.julialang.org/t/ctesn-code-packages/71279)

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**Author:** [@wkharold](https://discourse.julialang.org/u/wkharold)\
**Replies:** 0\
**Last updated:** [November 10, 2021, 6:48pm UTC](https://discourse.julialang.org/t/ctesn-code-packages/71279 "2021-11-10T18:48:32Z")

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I’m looking for the code used in the Continuous-Time Echo State Network paper. Surrogages.jl is referenced in the paper, and I found the ReservoirComputing.jl package but on first glance neither illustrates how to get th…

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## [Makie: categorical x variables](https://discourse.julialang.org/t/makie-categorical-x-variables/71263)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [November 10, 2021, 4:43pm UTC](https://discourse.julialang.org/t/makie-categorical-x-variables/71263 "2021-11-10T16:43:28Z")

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Hi, I recently moved from Plots to Makie and I am trying to make a box plot where each box aggregates data w.r.t. a real variable x. However the three categories are not evenly spaced. You can see a MWE here which prod…

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## [\[Article\] Using Julia to compare evolutionary game theory to agent based modelling](https://discourse.julialang.org/t/article-using-julia-to-compare-evolutionary-game-theory-to-agent-based-modelling/59809)

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**Author:** [@jacobusmmsmit](https://discourse.julialang.org/u/jacobusmmsmit)\
**Replies:** 5\
**Last updated:** [November 10, 2021, 2:14pm UTC](https://discourse.julialang.org/t/article-using-julia-to-compare-evolutionary-game-theory-to-agent-based-modelling/59809 "2021-11-10T14:14:41Z")

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Hello all, I recently completed an undergraduate research project with Warwick’s Data Science Society. I had an idea to compare simulation to analytic methods while writing an essay for one of my economics modules and I …

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## [JuMP 0.22 is released](https://discourse.julialang.org/t/jump-0-22-is-released/71241)

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**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 0\
**Last updated:** [November 10, 2021, 4:09am UTC](https://discourse.julialang.org/t/jump-0-22-is-released/71241 "2021-11-10T04:09:00Z")

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Dear all, We’re happy to announce the release of JuMP v0.22 and MathOptInterface v0.10, which completes a major milestone on our path to JuMP v1.0. Indeed, similar to how Julia v1.0 was Julia v0.7 with deprecations rem…

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## [\[ANN\] I started a package for writing CAD design in Julia](https://discourse.julialang.org/t/ann-i-started-a-package-for-writing-cad-design-in-julia/53299)

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**Author:** [@circonflexe](https://discourse.julialang.org/u/circonflexe)\
**Replies:** 12\
**Last updated:** [November 9, 2021, 6:52am UTC](https://discourse.julialang.org/t/ann-i-started-a-package-for-writing-cad-design-in-julia/53299 "2021-11-09T06:52:22Z")

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As the title says, I started writing a package for defining CAD objects in Julia. Why would this be useful? I believe it is useful to have an alternative to OpenSCAD which offers all the advantages of a full-fledged pr…

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## [Gadfly can't do Time values?](https://discourse.julialang.org/t/gadfly-cant-do-time-values/71187)

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**Author:** [@luc-j-bourhis](https://discourse.julialang.org/u/luc-j-bourhis)\
**Replies:** 0\
**Last updated:** [November 9, 2021, 8:20am UTC](https://discourse.julialang.org/t/gadfly-cant-do-time-values/71187 "2021-11-09T08:20:13Z")

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It seems that Gadly cannot handle Time on the x-axis (from Dates) as shown below. Would there be a package that could plug that hole? Or do I have to use Period instead as suggested by the error message? Or am I missing …

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## [GalacticOptim with AmplNLWriter optimizer](https://discourse.julialang.org/t/galacticoptim-with-amplnlwriter-optimizer/71137)

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**Author:** [@ver\_kh](https://discourse.julialang.org/u/ver_kh)\
**Replies:** 10\
**Last updated:** [November 9, 2021, 1:33am UTC](https://discourse.julialang.org/t/galacticoptim-with-amplnlwriter-optimizer/71137 "2021-11-09T01:33:43Z")

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Hello! I’m trying to use GalacticOptim.jl with AmplNLWriter.jl optimizer but it’s not working. using GalacticOptim, AmplNLWriter, Ipopt\_jll rosenbrock(x,p) = (p\[1\] - x\[1\])^2 + p\[2\] \* (x\[2\] - x\[1\]^2)^2 x0 = zeros(2) …

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## [Does DecisionTreeClassifier support missing data in the predictors?](https://discourse.julialang.org/t/does-decisiontreeclassifier-support-missing-data-in-the-predictors/71013)

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**Author:** [@Rahul](https://discourse.julialang.org/u/Rahul)\
**Replies:** 3\
**Last updated:** [November 8, 2021, 8:26pm UTC](https://discourse.julialang.org/t/does-decisiontreeclassifier-support-missing-data-in-the-predictors/71013 "2021-11-08T20:26:43Z")

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I cannot pass missing data to train DecisionTreeClassifier in MLJ. Is this not supported? Although the machine function gave me a warning, I tried to run fit! and it threw and error that the scitype of X isn’t supported. …

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## [Problem in expressing the nonlinear objective](https://discourse.julialang.org/t/problem-in-expressing-the-nonlinear-objective/71127)

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**Author:** [@FH96](https://discourse.julialang.org/u/FH96)\
**Replies:** 3\
**Last updated:** [November 8, 2021, 5:50pm UTC](https://discourse.julialang.org/t/problem-in-expressing-the-nonlinear-objective/71127 "2021-11-08T17:50:48Z")

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Hi, I’m trying to express the NLobjective of a problem which is something like this : sum((A\*v\_j -v\_exp)^2) (A is a matrix) I tried different forms and I got error in each case #@NLobjective(model,Min,sum((dot(module\_f…

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## [Label vectors in Plots](https://discourse.julialang.org/t/label-vectors-in-plots/71156)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 2\
**Last updated:** [November 8, 2021, 5:21pm UTC](https://discourse.julialang.org/t/label-vectors-in-plots/71156 "2021-11-08T17:21:56Z")

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Hi all, Is it possible to label vectors in a plot rather than in the legend? Here is an example where I would like to label the vectors A and B. using Plots plot( sqrt.(\[0,.5\]), sqrt.(\[0,.5\]), xlims = (-1.…

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## [Limited parallel downloads](https://discourse.julialang.org/t/limited-parallel-downloads/71146)

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**Author:** [@robertdj](https://discourse.julialang.org/u/robertdj)\
**Replies:** 7\
**Last updated:** [November 8, 2021, 4:09pm UTC](https://discourse.julialang.org/t/limited-parallel-downloads/71146 "2021-11-08T16:09:09Z")

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I want to make a large number of REST calls to download files. Each call is slow and I can only make a certain number of concurrent downloads (say N). I would like to max out on the number of concurrent calls. I imagine…

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## [Problem with CUDAv3](https://discourse.julialang.org/t/problem-with-cudav3/71118)

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**Author:** [@shiroghost](https://discourse.julialang.org/u/shiroghost)\
**Replies:** 9\
**Last updated:** [November 8, 2021, 1:19pm UTC](https://discourse.julialang.org/t/problem-with-cudav3/71118 "2021-11-08T13:19:30Z")

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I have been using CUDAv2.4 and everything has worked perfect. But after upgrading, I have found that many kernels fail to compile. Even a simple kernel: function krnl\_foo!(ac,bc) b = threadIdx().x …

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## [\[Turing\] Using a random variable as an index](https://discourse.julialang.org/t/turing-using-a-random-variable-as-an-index/66756)

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**Author:** [@a\_garval](https://discourse.julialang.org/u/a_garval)\
**Replies:** 2\
**Last updated:** [November 8, 2021, 11:46am UTC](https://discourse.julialang.org/t/turing-using-a-random-variable-as-an-index/66756 "2021-11-08T11:46:21Z")

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Hey everyone, I’m trying to run some examples from Bayesian Methods for Hackers. The example I’m working on is a simple Poisson model. I want to go further and investigate if we could find different a specific day on whi…

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## [DomainError in TemporalGPs](https://discourse.julialang.org/t/domainerror-in-temporalgps/70708)

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**Author:** [@jzr](https://discourse.julialang.org/u/jzr)\
**Replies:** 7\
**Last updated:** [November 8, 2021, 11:32am UTC](https://discourse.julialang.org/t/domainerror-in-temporalgps/70708 "2021-11-08T11:32:54Z")

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I’m trying to fit a GP with TemporalGPs. Sometimes I get a DomainError when it attempts to sqrt a negative number. When that happens I usually just guess again at some initial parameters and re-run it. Sometimes that doe…

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## [Allocation of Memory while evaluate a model](https://discourse.julialang.org/t/allocation-of-memory-while-evaluate-a-model/71064)

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**Author:** [@HenrZu](https://discourse.julialang.org/u/HenrZu)\
**Replies:** 7\
**Last updated:** [November 8, 2021, 11:02am UTC](https://discourse.julialang.org/t/allocation-of-memory-while-evaluate-a-model/71064 "2021-11-08T11:02:05Z")

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While working on the performance of a model used in a numerical simulation, I noticed that memory is allocated every time a model is evaluated. Since I call the model several times within the simulation, there is a sign…

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## [Problem standardizing data with MLJ + NaN predictions in Flux](https://discourse.julialang.org/t/problem-standardizing-data-with-mlj-nan-predictions-in-flux/70923)

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**Author:** [@lfenzo](https://discourse.julialang.org/u/lfenzo)\
**Replies:** 3\
**Last updated:** [November 8, 2021, 2:58am UTC](https://discourse.julialang.org/t/problem-standardizing-data-with-mlj-nan-predictions-in-flux/70923 "2021-11-08T02:58:36Z")

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I’m new to Julia and Flux so I suspect this may be something dumb that I may be missing… I was trying to do some pre-processing in order to train a NN using Flux and ended up stuck with two problems: The predictions …

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## [Help with global optimizers in NLopt and GalacticOptim](https://discourse.julialang.org/t/help-with-global-optimizers-in-nlopt-and-galacticoptim/71084)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 11\
**Last updated:** [November 8, 2021, 1:29am UTC](https://discourse.julialang.org/t/help-with-global-optimizers-in-nlopt-and-galacticoptim/71084 "2021-11-08T01:29:00Z")

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This is a very simple optimization problem, but for some reason I cannot get NLopt to converge: using GalacticOptim using NLopt rosenbrock(x, p) = (p\[1\] - x\[1\])^2 + p\[2\] \* (x\[2\] - x\[1\]^2)^2 x0 = zeros(2) p = \[1.0, 10…

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## [Consistent use of FilterCoefficients in DSP.jl?](https://discourse.julialang.org/t/consistent-use-of-filtercoefficients-in-dsp-jl/71119)

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**Author:** [@mbaz](https://discourse.julialang.org/u/mbaz)\
**Replies:** 0\
**Last updated:** [November 8, 2021, 1:22am UTC](https://discourse.julialang.org/t/consistent-use-of-filtercoefficients-in-dsp-jl/71119 "2021-11-08T01:22:53Z")

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In DSP.jl, some filter design commands return a filter object, while others (like remez) return a plain Float64 vector. This is inconvenient because many of the package functions don’t take vectors as arguments. I have …

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## [Conditional sum in constraint](https://discourse.julialang.org/t/conditional-sum-in-constraint/71100)

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**Author:** [@Fabrizio](https://discourse.julialang.org/u/Fabrizio)\
**Replies:** 8\
**Last updated:** [November 7, 2021, 11:53pm UTC](https://discourse.julialang.org/t/conditional-sum-in-constraint/71100 "2021-11-07T23:53:02Z")

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Dear all, the piece of code below works well with Jump until Ver 0.20.6, newer version of JuMP give to to me the error LoadError: KeyError: key (1, 1, 2, 1) not found The BRANCH set is a sparse set indicating the netwo…

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