# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=391

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**Page:** 392

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## [Solving ODE system with PINN](https://discourse.julialang.org/t/solving-ode-system-with-pinn/54750)

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**Author:** [@Honza9723](https://discourse.julialang.org/u/Honza9723)\
**Replies:** 7\
**Last updated:** [February 7, 2021, 2:27am UTC](https://discourse.julialang.org/t/solving-ode-system-with-pinn/54750 "2021-02-07T02:27:04Z")

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Dear All, I am trying to solve system of two ordinary differential equations. 𝝫’(x) = (λ-1/v(x))f(x) v’(x) = x^3(λf(x)/(λf(x)x-2𝝫(x)))^2 With boundary conditions 𝝫(x\_low) = 0 𝝫(x\_high) = 0 v(x) and 𝝫(x) are unknow…

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## [Sparse vectors and BigFloat Heisenbug](https://discourse.julialang.org/t/sparse-vectors-and-bigfloat-heisenbug/54707)

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**Author:** [@mbesancon](https://discourse.julialang.org/u/mbesancon)\
**Replies:** 4\
**Last updated:** [February 6, 2021, 10:14am UTC](https://discourse.julialang.org/t/sparse-vectors-and-bigfloat-heisenbug/54707 "2021-02-06T10:14:28Z")

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I have in some weird side effect with structs of sparse vectors of BigFloats, where operating on a copy of the sum seems to change the struct itself. In spirit, the structure of the code looks like below. After a copyin…

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## [Getindex in Model Constraints assign](https://discourse.julialang.org/t/getindex-in-model-constraints-assign/54678)

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**Author:** [@user1200](https://discourse.julialang.org/u/user1200)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 9:20pm UTC](https://discourse.julialang.org/t/getindex-in-model-constraints-assign/54678 "2021-02-05T21:20:16Z")

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Hello Is there a way to use getIndex or findfirst function in Constraints in Model? Usage: Get maximum value from “1 vector(column)”-but remember just its index, for example 8th. Then get value from “another vector(co…

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## [Vectorising Turing models](https://discourse.julialang.org/t/vectorising-turing-models/54700)

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**Author:** [@drbenvincent](https://discourse.julialang.org/u/drbenvincent)\
**Replies:** 1\
**Last updated:** [February 5, 2021, 7:49pm UTC](https://discourse.julialang.org/t/vectorising-turing-models/54700 "2021-02-05T19:49:44Z")

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I’m testing out vectorization in Turing models. I’ve managed to get a model that too 195 seconds, down to 60 seconds. But I wonder if there is anything obvious I’m missing in order to get even further benefits? using Tu…

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## [JLBoost key error](https://discourse.julialang.org/t/jlboost-key-error/54702)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 0\
**Last updated:** [February 5, 2021, 7:25pm UTC](https://discourse.julialang.org/t/jlboost-key-error/54702 "2021-02-05T19:25:33Z")

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Hi All, I am trying to blindly use JLBoost on a big dataset with 2381 features and 600 000 samples. I have automatically converted the feature matrix to the DataFrame using df = DataFrame(x, :auto), add labels as df.y =…

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## [How to add multiple same rows in a array](https://discourse.julialang.org/t/how-to-add-multiple-same-rows-in-a-array/54695)

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**Author:** [@Shazman](https://discourse.julialang.org/u/Shazman)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 4:58pm UTC](https://discourse.julialang.org/t/how-to-add-multiple-same-rows-in-a-array/54695 "2021-02-05T16:58:27Z")

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Hi I have a array P (1x41227) and I want to add 27856 rows with same elements like P. how can I do it ? thanks 1×41227 Array{Float64,2}: 0.0361328 -0.00634766 0.774414 0.620117 … 0.255859 0.491211 0.666992

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## [Composing probabilistic models](https://discourse.julialang.org/t/composing-probabilistic-models/54604)

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**Author:** [@plafl](https://discourse.julialang.org/u/plafl)\
**Replies:** 6\
**Last updated:** [February 5, 2021, 4:20pm UTC](https://discourse.julialang.org/t/composing-probabilistic-models/54604 "2021-02-05T16:20:35Z")

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Hi, I’m quite new to Julia and I have stumbled upon Turing. It looks great and the documentation is nice but either I have missed something or simply it’s not possible. I want to define models in a modular way and combi…

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## [Solve function for non full rank systems of equations](https://discourse.julialang.org/t/solve-function-for-non-full-rank-systems-of-equations/54611)

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**Author:** [@Andres\_Legarra](https://discourse.julialang.org/u/Andres_Legarra)\
**Replies:** 4\
**Last updated:** [February 5, 2021, 1:27pm UTC](https://discourse.julialang.org/t/solve-function-for-non-full-rank-systems-of-equations/54611 "2021-02-05T13:27:05Z")

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Typical OLS ( X'X a = X'y ) with 2 or more dummy (or cross-classified) effects are not full rank and they have infinite solutions. (Minimal example below.) They are conceptually solved using generalized inverses, to obta…

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## [Elegant kernel for vectors in matrix](https://discourse.julialang.org/t/elegant-kernel-for-vectors-in-matrix/54648)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 3\
**Last updated:** [February 5, 2021, 12:57pm UTC](https://discourse.julialang.org/t/elegant-kernel-for-vectors-in-matrix/54648 "2021-02-05T12:57:32Z")

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Hello, I’m trying to write a kernel that does some operations on vectors using CUDA.jl and @cuda. My code is essentially this: points = Nx3 matrix with x,y,z coordinates of points elements = Nx4 matrix with integers th…

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## [Plots.jl - Combined Histogram and Distribution](https://discourse.julialang.org/t/plots-jl-combined-histogram-and-distribution/54656)

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**Author:** [@phillc](https://discourse.julialang.org/u/phillc)\
**Replies:** 4\
**Last updated:** [February 5, 2021, 9:03am UTC](https://discourse.julialang.org/t/plots-jl-combined-histogram-and-distribution/54656 "2021-02-05T09:03:50Z")

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I’m trying to convert some plots from R based examples to Julia. The R examples are found here: Essentially the single plot is a histogram of a probability distribution, with the corresponding Beta distribution plotte…

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## [Sum of Flux.params](https://discourse.julialang.org/t/sum-of-flux-params/54608)

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**Author:** [@anon74562486](https://discourse.julialang.org/u/anon74562486)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 8:32pm UTC](https://discourse.julialang.org/t/sum-of-flux-params/54608 "2021-02-04T20:32:58Z")

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I tried these two functions to get the l2 regularization term for a NN model: function ℓ₂(a) s = zero(Float32) for i in a s += sum(i.^2) end s end function l₂(a) s = zero(Float32) Lₐ = l…

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## [Bounded parameters w/ Optim](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552)

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**Author:** [@pyrex41](https://discourse.julialang.org/u/pyrex41)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 6:51pm UTC](https://discourse.julialang.org/t/bounded-parameters-w-optim/54552 "2021-02-04T18:51:13Z")

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I have been working on fitting some non-linear models, and have been using Optim. For models where the parameters space is bounded, one can obviously use Box Constraints. Before I read how to this, however, I had been tr…

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## [Which Optimization package for large-scale structured nonlinear problems](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449)

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**Author:** [@egvila](https://discourse.julialang.org/u/egvila)\
**Replies:** 6\
**Last updated:** [February 4, 2021, 6:43pm UTC](https://discourse.julialang.org/t/which-optimization-package-for-large-scale-structured-nonlinear-problems/54449 "2021-02-04T18:43:52Z")

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Hello everyone, As the title says, I would like some insight on what Julia Optimization package would be most appropriate to efficiently solve nonlinear problems with potentially exploitable sparsity structures (e.g. bl…

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## [How to export data from an array](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 3\
**Last updated:** [February 4, 2021, 6:29pm UTC](https://discourse.julialang.org/t/how-to-export-data-from-an-array/54555 "2021-02-04T18:29:49Z")

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Maybe my question is a little repetitive compared to the last one I posted here. In this model, I would like to export the data that is in i to a .CSV file. When compiling the model the answer I have in .CSV is this: …

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## [For Loops in Luxor](https://discourse.julialang.org/t/for-loops-in-luxor/54197)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 20\
**Last updated:** [February 4, 2021, 5:51pm UTC](https://discourse.julialang.org/t/for-loops-in-luxor/54197 "2021-02-04T17:51:09Z")

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When I create a checker pattern using the rect function, it works perfectly: @svg begin Drawing(2000,2000) background("white") sethue("black") rect(500,0,500,500,:fill) rect(1500,0,500,500,:fill) rect(0,500,500,50…

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## [Linear system problems](https://discourse.julialang.org/t/linear-system-problems/54519)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 35\
**Last updated:** [February 4, 2021, 10:57am UTC](https://discourse.julialang.org/t/linear-system-problems/54519 "2021-02-04T10:57:31Z")

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Hello, I’m writing some code that solves A\*x=b, where A can be quite big (say 10000x10000, hopefully bigger in the future). A is not sparse (at least for now) and might be poorly conditioned. Might even have multiple so…

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## [Seeking advice on contributing to Julia: A faster Lasso solver](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023)

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**Author:** [@barankarakus](https://discourse.julialang.org/u/barankarakus)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 7:02am UTC](https://discourse.julialang.org/t/seeking-advice-on-contributing-to-julia-a-faster-lasso-solver/42023 "2021-02-04T07:02:31Z")

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Hi there, I’m a Master’s student in Statistics. I’ve recently been researching ‘safe screening rules’ for accelerating Lasso solvers. These can improve computation times by orders of magnitude when the number of feature…

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## [Gradient penalty problems with relu](https://discourse.julialang.org/t/gradient-penalty-problems-with-relu/54594)

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**Author:** [@ancorso](https://discourse.julialang.org/u/ancorso)\
**Replies:** 0\
**Last updated:** [February 4, 2021, 6:25am UTC](https://discourse.julialang.org/t/gradient-penalty-problems-with-relu/54594 "2021-02-04T06:25:32Z")

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I am trying to implement the gradient penalty of WGAN-GP in Flux and Zygote, but am getting an error when I have relus in my model. See the following MWE. If I switch the relu to a tanh then it works fine. Thoughts? usi…

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## [EnsembleSummary deprecated?](https://discourse.julialang.org/t/ensemblesummary-deprecated/54570)

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**Author:** [@zenkavi](https://discourse.julialang.org/u/zenkavi)\
**Replies:** 1\
**Last updated:** [February 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/ensemblesummary-deprecated/54570 "2021-02-04T00:22:48Z")

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I’m very new to Julia so I might be misinterpreting what’s happening here. The EnsembleSummary function stopped working for me which doesn’t seem to make sense since it is part of SciMLBase so maybe dependencies are mes…

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## [Optim with autodiff return error when optimize paralleled objective function](https://discourse.julialang.org/t/optim-with-autodiff-return-error-when-optimize-paralleled-objective-function/54496)

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**Author:** [@zxjroger](https://discourse.julialang.org/u/zxjroger)\
**Replies:** 9\
**Last updated:** [February 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/optim-with-autodiff-return-error-when-optimize-paralleled-objective-function/54496 "2021-02-04T00:22:45Z")

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I have a very complicated objective function which involves some distributed call. I would like to optimize the function using Optim with Forward Difference. However, it reports an error. This is the MWE: using Distribu…

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## [Network ODE Model; Type error with ForwardDiff Dual](https://discourse.julialang.org/t/network-ode-model-type-error-with-forwarddiff-dual/54379)

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**Author:** [@PavanChaggar](https://discourse.julialang.org/u/PavanChaggar)\
**Replies:** 9\
**Last updated:** [February 3, 2021, 10:37pm UTC](https://discourse.julialang.org/t/network-ode-model-type-error-with-forwarddiff-dual/54379 "2021-02-03T22:37:59Z")

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Hello, I am new to Turing and trying to use it for my research on network ODE models. I have started with a simple model (network diffusion) \\frac{du}{dt} = - \\rho \\mathbf{L} \\mathbf{u} and am trying to infer the va…

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## [Is there @code\_warntype output documentation anywhere?](https://discourse.julialang.org/t/is-there-code-warntype-output-documentation-anywhere/54506)

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**Author:** [@zenkavi](https://discourse.julialang.org/u/zenkavi)\
**Replies:** 3\
**Last updated:** [February 3, 2021, 7:41pm UTC](https://discourse.julialang.org/t/is-there-code-warntype-output-documentation-anywhere/54506 "2021-02-03T19:41:35Z")

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Where can I find more information on understanding the output of @code\_warntype mentioned in Turing Performance Tips? I’m trying to use it to debug some ForwardDiff Dual Type errors mentioned often (e.g. one recent exam…

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## [GLMakie: recording a movie without displaying intermediate frames?](https://discourse.julialang.org/t/glmakie-recording-a-movie-without-displaying-intermediate-frames/54537)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 1\
**Last updated:** [February 3, 2021, 7:30pm UTC](https://discourse.julialang.org/t/glmakie-recording-a-movie-without-displaying-intermediate-frames/54537 "2021-02-03T19:30:29Z")

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Hi, I would like to use GLMakie on a remote machine without exporting a display. Note that I was not able to use WGLMakie because of speed issue neither CairoMakie because these are 3D plots. Is it possible to record …

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## [Issue with MvNormal and Turing](https://discourse.julialang.org/t/issue-with-mvnormal-and-turing/54541)

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**Author:** [@Carter](https://discourse.julialang.org/u/Carter)\
**Replies:** 8\
**Last updated:** [February 3, 2021, 7:29pm UTC](https://discourse.julialang.org/t/issue-with-mvnormal-and-turing/54541 "2021-02-03T19:29:07Z")

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I’m trying to recreate the model from chapter 5.1 to estimate correlation from the book Bayesian Cognitive Modeling: A Practical Course using Turing. However, I keep running into an issue with MvNormal where it does not …

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## [Calculating power transfer distribution factor (PTDF) matrix using PowerModels.jl](https://discourse.julialang.org/t/calculating-power-transfer-distribution-factor-ptdf-matrix-using-powermodels-jl/42668)

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**Author:** [@gobs](https://discourse.julialang.org/u/gobs)\
**Replies:** 7\
**Last updated:** [February 3, 2021, 5:46pm UTC](https://discourse.julialang.org/t/calculating-power-transfer-distribution-factor-ptdf-matrix-using-powermodels-jl/42668 "2021-02-03T17:46:10Z")

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I want to obtain a PTDF matrix to use in my power system optimisation model using data in PowerModels.jl format (I also raised an issue for this to be integrated into PowerModels.jl itself: https://github.com/lanl-ansi/P…

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## [Package for visualizing wireframe cube](https://discourse.julialang.org/t/package-for-visualizing-wireframe-cube/54400)

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**Author:** [@EL-Bakkali-Jaafar](https://discourse.julialang.org/u/EL-Bakkali-Jaafar)\
**Replies:** 6\
**Last updated:** [February 3, 2021, 3:41pm UTC](https://discourse.julialang.org/t/package-for-visualizing-wireframe-cube/54400 "2021-02-03T15:41:37Z")

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Hi all, What I am looking for is a package to draw a wireframe cube and to draw segment connecting two 3d points. Thanks.

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## [Turing model not optimising; unstable ODE solutions](https://discourse.julialang.org/t/turing-model-not-optimising-unstable-ode-solutions/54526)

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**Author:** [@PavanChaggar](https://discourse.julialang.org/u/PavanChaggar)\
**Replies:** 2\
**Last updated:** [February 3, 2021, 1:16pm UTC](https://discourse.julialang.org/t/turing-model-not-optimising-unstable-ode-solutions/54526 "2021-02-03T13:16:47Z")

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Hi, I am getting an integration error with my Turing model. I have searched around but haven’t seen anything similar on discourse. The ODE model is set up as follows: using DifferentialEquations, LightGraphs, Random, …

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## [Inconsistance between @NLobjective and @objective](https://discourse.julialang.org/t/inconsistance-between-nlobjective-and-objective/54520)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [February 3, 2021, 9:39am UTC](https://discourse.julialang.org/t/inconsistance-between-nlobjective-and-objective/54520 "2021-02-03T09:39:21Z")

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Let’s consider the following model: model = Model(with\_optimizer(Ipopt.Optimizer)) @variable(model, x \>= 0) @variable(model, y \>= 1) Then the macro @objective can be used both as: @objective(model, Min, x+2\*y) or @o…

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## [Plotting a decision tree and extracting the split criteria](https://discourse.julialang.org/t/plotting-a-decision-tree-and-extracting-the-split-criteria/54503)

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**Author:** [@dataopt](https://discourse.julialang.org/u/dataopt)\
**Replies:** 0\
**Last updated:** [February 3, 2021, 12:46am UTC](https://discourse.julialang.org/t/plotting-a-decision-tree-and-extracting-the-split-criteria/54503 "2021-02-03T00:46:35Z")

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I am new to MLJ coming from R for statistical learning. I have two newbie questions: Is there a way to plot a decision tree? Is there a way to extract the structure of the tree with the split criteria?

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## [Precompile errors Makie (AbstractPlotting)](https://discourse.julialang.org/t/precompile-errors-makie-abstractplotting/53810)

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**Author:** [@fyzycyst](https://discourse.julialang.org/u/fyzycyst)\
**Replies:** 2\
**Last updated:** [February 2, 2021, 5:48pm UTC](https://discourse.julialang.org/t/precompile-errors-makie-abstractplotting/53810 "2021-02-02T17:48:42Z")

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Attempted to try out Makie, but the precompile fails. I’m including a sample for the AbstractPlotting precompile, but it’s the same for CairoMakie, etc. I know similar problems are reported from time to time, but none of…

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