# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=72

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**Page:** 73

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## [Universal Differential Equations with Ensemble Problem](https://discourse.julialang.org/t/universal-differential-equations-with-ensemble-problem/121663)

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**Author:** [@Piyush](https://discourse.julialang.org/u/Piyush)\
**Replies:** 6\
**Last updated:** [November 20, 2024, 11:03am UTC](https://discourse.julialang.org/t/universal-differential-equations-with-ensemble-problem/121663 "2024-11-20T11:03:43Z")

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I am facing issues trying to develop UDE model using the Ensemble interface Kindly help me out. Here is the sample code and error I get using CSV, DataFrames, XLSX using Optimization, OptimizationPolyalgorithms,Optimiz…

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## [Reinitializing the InitializationProb of an ODEProblem](https://discourse.julialang.org/t/reinitializing-the-initializationprob-of-an-odeproblem/122778)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 6\
**Last updated:** [November 20, 2024, 7:27am UTC](https://discourse.julialang.org/t/reinitializing-the-initializationprob-of-an-odeproblem/122778 "2024-11-20T07:27:57Z")

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I am trying to re-initialize an ODEProblem with a new x-position on the last point pos\[1, end\]. A bit like in the example here: Initialization of ODESystems · ModelingToolkit.jl dt = 0.05 tol = 1e-6 tspan = …

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## [Adding slider that will show a vertical line across my plot?](https://discourse.julialang.org/t/adding-slider-that-will-show-a-vertical-line-across-my-plot/122605)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 2\
**Last updated:** [November 20, 2024, 4:39am UTC](https://discourse.julialang.org/t/adding-slider-that-will-show-a-vertical-line-across-my-plot/122605 "2024-11-20T04:39:11Z")

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Hi all, I have a stacked plot with shared x- and y- axes, and the main goal of this is to quickly see where general trends compare over each plot – and I think having a line over each plot that I can scan over would mak…

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## [Kernel methods inside of Flux](https://discourse.julialang.org/t/kernel-methods-inside-of-flux/122820)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [November 20, 2024, 4:01am UTC](https://discourse.julialang.org/t/kernel-methods-inside-of-flux/122820 "2024-11-20T04:01:51Z")

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I’m experimenting with setting up a classical RBF kernel method wtihin Flux, i.e., I want to train the model: \\sum\_{i=1}^n a\_i k(x, X\_i), where, for simplicity, take the kernel k to be a Gaussian. n is fixed, and the…

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## [Most efficient way of retrieving dual solutions iteratively](https://discourse.julialang.org/t/most-efficient-way-of-retrieving-dual-solutions-iteratively/122790)

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**Author:** [@BMI\_OR](https://discourse.julialang.org/u/BMI_OR)\
**Replies:** 1\
**Last updated:** [November 18, 2024, 9:38pm UTC](https://discourse.julialang.org/t/most-efficient-way-of-retrieving-dual-solutions-iteratively/122790 "2024-11-18T21:38:03Z")

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I have implemented an algorithm where at each iteration I need to solve an optimization model and retrieve its dual solution. Currently, I am using dual.() to get the solution, and I am seeing that this function is also …

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## [How to accelerate GPU operation？](https://discourse.julialang.org/t/how-to-accelerate-gpu-operation/122506)

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**Author:** [@zhenweilin](https://discourse.julialang.org/u/zhenweilin)\
**Replies:** 12\
**Last updated:** [November 18, 2024, 8:29pm UTC](https://discourse.julialang.org/t/how-to-accelerate-gpu-operation/122506 "2024-11-18T20:29:15Z")

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Hello, everyone in the Julia community. I’m currently writing a project about GPU. I hope to perform certain operations on some parts of a vector. These operations can be parallelized, but when I did it on the CPU, I fou…

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## [\`@assert\` handling for symbolically registered functions in MTK](https://discourse.julialang.org/t/assert-handling-for-symbolically-registered-functions-in-mtk/122783)

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**Author:** [@Sushrut\_Deshpande](https://discourse.julialang.org/u/Sushrut_Deshpande)\
**Replies:** 2\
**Last updated:** [November 18, 2024, 6:45pm UTC](https://discourse.julialang.org/t/assert-handling-for-symbolically-registered-functions-in-mtk/122783 "2024-11-18T18:45:57Z")

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Hello, I would like to know if it is possible to have assert statements on parameters of an MTK component. For general @assert a \>1 cases it hit the error where symbolic expression appears in Boolean context. Toy Exam…

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## [Zoom in/out only works for first drawing on a figure](https://discourse.julialang.org/t/zoom-in-out-only-works-for-first-drawing-on-a-figure/122752)

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**Author:** [@AMB](https://discourse.julialang.org/u/AMB)\
**Replies:** 1\
**Last updated:** [November 18, 2024, 2:57pm UTC](https://discourse.julialang.org/t/zoom-in-out-only-works-for-first-drawing-on-a-figure/122752 "2024-11-18T14:57:49Z")

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Hi All. I’m wondering if somebody can explain the following behavior. I draw something, empty! the axis scene, and then draw something similar. All the drawing works as expected but I’ve noticed that while I can zoom in…

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## [Linearization & ModelingToolkit -- what is wrong?](https://discourse.julialang.org/t/linearization-modelingtoolkit-what-is-wrong/122766)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 2\
**Last updated:** [November 18, 2024, 1:15pm UTC](https://discourse.julialang.org/t/linearization-modelingtoolkit-what-is-wrong/122766 "2024-11-18T13:15:18Z")

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I’m simulating two nonlinear RC circuits in series (nonlinear resistances, ipp(u) instead of ipp=u/R). ModelingToolkit code + simulation# Importing packages using ModelingToolkit using ModelingToolkit: t\_nounits as t, D…

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## [Turing's negative binomial regression with horseshoe prior failing sometimes](https://discourse.julialang.org/t/turings-negative-binomial-regression-with-horseshoe-prior-failing-sometimes/121574)

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**Author:** [@ayushpatnaikgit](https://discourse.julialang.org/u/ayushpatnaikgit)\
**Replies:** 1\
**Last updated:** [November 18, 2024, 6:46am UTC](https://discourse.julialang.org/t/turings-negative-binomial-regression-with-horseshoe-prior-failing-sometimes/121574 "2024-11-18T06:46:32Z")

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Hi, I am trying to do a negative binomial regression using Turing. I am using the horseshoe prior. Here is my code: using Turing, StatsModels, RDatasets, Random sanction = dataset("Zelig", "sanction") function Negati…

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## [ModellingToolkit/ optimal control training](https://discourse.julialang.org/t/modellingtoolkit-optimal-control-training/122751)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 2\
**Last updated:** [November 18, 2024, 5:34am UTC](https://discourse.julialang.org/t/modellingtoolkit-optimal-control-training/122751 "2024-11-18T05:34:58Z")

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A colleague of me is going to attend a three-day CASADI training. I told him: Only advantage of CASADI over ModingToolkit is: “CASADI supports special functionality for quadratic programming problems”, in all other asp…

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## [Help me think through an efficient workflow for GPS data:](https://discourse.julialang.org/t/help-me-think-through-an-efficient-workflow-for-gps-data/122563)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 4\
**Last updated:** [November 18, 2024, 1:00am UTC](https://discourse.julialang.org/t/help-me-think-through-an-efficient-workflow-for-gps-data/122563 "2024-11-18T01:00:31Z")

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I have 371-files of detrended GPS data formatted like such: \[decimalyear, longitude, latitude, value, sigma, station\] My end goal is plot smoothed data by region to highlight an anomaly I’m looking at for my masters th…

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## [Generating C code from JuMP.jl model](https://discourse.julialang.org/t/generating-c-code-from-jump-jl-model/122736)

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**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 7\
**Last updated:** [November 17, 2024, 10:20pm UTC](https://discourse.julialang.org/t/generating-c-code-from-jump-jl-model/122736 "2024-11-17T22:20:53Z")

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I have defined an MILP model in JuMP.jl. This model works great. Now I would like to implement it on a real time controller in C. Is there a way to generate C code for my model so that I can just copy paste it into my p…

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## [Adding PID controller to a MIMO state space system](https://discourse.julialang.org/t/adding-pid-controller-to-a-mimo-state-space-system/122681)

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**Author:** [@victor](https://discourse.julialang.org/u/victor)\
**Replies:** 7\
**Last updated:** [November 17, 2024, 6:55pm UTC](https://discourse.julialang.org/t/adding-pid-controller-to-a-mimo-state-space-system/122681 "2024-11-17T18:55:12Z")

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I have a state space process with two inputs and one output. The inputs are highly coupled. I would like to add a PID controller to one of the inputs with the output as measurement value. But I’m having a hard time with …

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## [Julia ❤️ ABM tutorial series](https://discourse.julialang.org/t/julia-abm-tutorial-series/99300)

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**Author:** [@fbanning](https://discourse.julialang.org/u/fbanning)\
**Replies:** 1\
**Last updated:** [November 17, 2024, 5:23pm UTC](https://discourse.julialang.org/t/julia-abm-tutorial-series/99300 "2024-11-17T17:23:37Z")

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Julia :heart: ABM is a tutorial series on coding agent-based models in Julia. I write on it in irregular intervals - basically whenever I find some time to extend on it. List of issues so far: Julia :heart: ABM #0: Ag…

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## [MATLAB is faster for my large system of ODEs?](https://discourse.julialang.org/t/matlab-is-faster-for-my-large-system-of-odes/122610)

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**Author:** [@martru](https://discourse.julialang.org/u/martru)\
**Replies:** 21\
**Last updated:** [November 15, 2024, 6:12pm UTC](https://discourse.julialang.org/t/matlab-is-faster-for-my-large-system-of-odes/122610 "2024-11-15T18:12:50Z")

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Excuse the deliberately provocative title :slight\_smile: I have a very large system of ODEs of the form: dot{x} = Ax + Bu A is a sparse matrix 5505x5505. B\*u is a 5505 element vector. Using ode45 in matlab, it solves …

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## [Error when running \`using Plots; pythonplot();\` in old environment](https://discourse.julialang.org/t/error-when-running-using-plots-pythonplot-in-old-environment/122670)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 6\
**Last updated:** [November 15, 2024, 4:09pm UTC](https://discourse.julialang.org/t/error-when-running-using-plots-pythonplot-in-old-environment/122670 "2024-11-15T16:09:41Z")

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I was loading an old Julia environment (maybe half a year old? It is 1.10.4). I then run julia\> using Plots julia\> pythonplot() And get a ERROR: InitError: PythonCall.PyException(PythonCall.Py(Ptr{PythonCall.C.PyObjec…

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## [Initial condition underdefined in NonlinearProblem](https://discourse.julialang.org/t/initial-condition-underdefined-in-nonlinearproblem/122619)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 7\
**Last updated:** [November 15, 2024, 9:36am UTC](https://discourse.julialang.org/t/initial-condition-underdefined-in-nonlinearproblem/122619 "2024-11-15T09:36:24Z")

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The following works: using ModelingToolkit, NonlinearSolve # Define a nonlinear system @variables x y z @parameters σ ρ β eqs = \[0 ~ σ \* (y - x) 0 ~ x \* (ρ - z) - y 0 ~ x \* y - β \* z\] @mtkbuild ns = Nonli…

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## [Get list of parameters from Turing model](https://discourse.julialang.org/t/get-list-of-parameters-from-turing-model/66278)

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**Author:** [@sijo](https://discourse.julialang.org/u/sijo)\
**Replies:** 16\
**Last updated:** [November 14, 2024, 10:50pm UTC](https://discourse.julialang.org/t/get-list-of-parameters-from-turing-model/66278 "2024-11-14T22:50:09Z")

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How can I get the list of parameters in a Turing model? I’m trying to generate programmatically a list of initial values to pass with init\_params, so I need to know the symbols, in the correct order. For example, given…

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## [Combine rows but keep all columns](https://discourse.julialang.org/t/combine-rows-but-keep-all-columns/122593)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 9\
**Last updated:** [November 14, 2024, 9:42pm UTC](https://discourse.julialang.org/t/combine-rows-but-keep-all-columns/122593 "2024-11-14T21:42:54Z")

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Hi all, due to the lack of copycalls kwarg in combine, I am not sure if there is a more efficient way to achieve what I want to do. The following code groups the example data frame by ID and then sums the values in Data…

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## [Unexpected behavior: containerized expression automatically redefined when included in interval constraint](https://discourse.julialang.org/t/unexpected-behavior-containerized-expression-automatically-redefined-when-included-in-interval-constraint/122648)

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**Author:** [@Eli\_Brock](https://discourse.julialang.org/u/Eli_Brock)\
**Replies:** 2\
**Last updated:** [November 14, 2024, 8:32pm UTC](https://discourse.julialang.org/t/unexpected-behavior-containerized-expression-automatically-redefined-when-included-in-interval-constraint/122648 "2024-11-14T20:32:14Z")

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When a containerized affine expression is included in an interval constraint, the expression seems to be automatically modified in-place to remove constants. MWE: using JuMP model = Model() @variable(model, x) @express…

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## [NonlinearSolve uses AD Jacobian even when I specify it analytically](https://discourse.julialang.org/t/nonlinearsolve-uses-ad-jacobian-even-when-i-specify-it-analytically/122608)

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**Author:** [@DanDoe](https://discourse.julialang.org/u/DanDoe)\
**Replies:** 3\
**Last updated:** [November 14, 2024, 3:32pm UTC](https://discourse.julialang.org/t/nonlinearsolve-uses-ad-jacobian-even-when-i-specify-it-analytically/122608 "2024-11-14T15:32:20Z")

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Hm, I recently tried specification of the Jacobian in this way - however, NonlinearSolve still tries to attempt to construct the Jacobian using AD. Has anything changed here?

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## [CairoMakie plots disappear once linked to an Illustrator file](https://discourse.julialang.org/t/cairomakie-plots-disappear-once-linked-to-an-illustrator-file/122492)

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**Author:** [@LorenzoFioroni](https://discourse.julialang.org/u/LorenzoFioroni)\
**Replies:** 6\
**Last updated:** [November 14, 2024, 1:29pm UTC](https://discourse.julialang.org/t/cairomakie-plots-disappear-once-linked-to-an-illustrator-file/122492 "2024-11-14T13:29:06Z")

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Hello everyone, I’m facing an issue with using CairoMakie and Adobe Illustrator 2025 that I hope someone here can help me with. The workflow involves generating some plots with CairoMakie, linking these plots into Illus…

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## [Newton + LineSearch in Hot Loop: Reduce allocations](https://discourse.julialang.org/t/newton-linesearch-in-hot-loop-reduce-allocations/122585)

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**Author:** [@DanDoe](https://discourse.julialang.org/u/DanDoe)\
**Replies:** 6\
**Last updated:** [November 14, 2024, 8:08am UTC](https://discourse.julialang.org/t/newton-linesearch-in-hot-loop-reduce-allocations/122585 "2024-11-14T08:08:18Z")

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I really like the NLsolve.jl package in conjunction with LineSearches.jl - great stuff! I have a scalar, relatively simple nonlinear equation that I can solve using res = nlsolve(gamma -\> f(gamma\[1\], bla, bla, bla), …

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## [How to cluster points with a maximum cluster size? Or find points with maximum diversity?](https://discourse.julialang.org/t/how-to-cluster-points-with-a-maximum-cluster-size-or-find-points-with-maximum-diversity/122348)

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**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 12\
**Last updated:** [November 14, 2024, 2:37am UTC](https://discourse.julialang.org/t/how-to-cluster-points-with-a-maximum-cluster-size-or-find-points-with-maximum-diversity/122348 "2024-11-14T02:37:05Z")

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Hi all, Used to do Data Science / Analytics in a previous role but haven’t done much (any) over the past 3 years. At work, I’d offload this problem to our Data Science team, but they don’t have the bandwidth and I have …

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## [Plots: use of \`twinx()\` and \`frame=:box\` looks ugly](https://discourse.julialang.org/t/plots-use-of-twinx-and-frame-box-looks-ugly/122581)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 1\
**Last updated:** [November 13, 2024, 7:32pm UTC](https://discourse.julialang.org/t/plots-use-of-twinx-and-frame-box-looks-ugly/122581 "2024-11-13T19:32:19Z")

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I like to use the frame keyword when plotting with Plots.jl – it makes the plot nicer, in my view. However, if I use twin ordinate axes, the default is ugly with frame=:box: Here is without frame specification: Next…

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## [Non-converging chains and slow runtime in Bayesian parameter estimation for wind turbine system](https://discourse.julialang.org/t/non-converging-chains-and-slow-runtime-in-bayesian-parameter-estimation-for-wind-turbine-system/122416)

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**Author:** [@Alvaro98](https://discourse.julialang.org/u/Alvaro98)\
**Replies:** 7\
**Last updated:** [November 13, 2024, 7:02pm UTC](https://discourse.julialang.org/t/non-converging-chains-and-slow-runtime-in-bayesian-parameter-estimation-for-wind-turbine-system/122416 "2024-11-13T19:02:44Z")

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Hello all, I’m quite new to Turing and Bayesian inference in general, and I’m trying to estimate parameters for the power coefficient Cp in a wind turbine aerodynamic model. The parametric expression for Cp has 6 parame…

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## [Small Vectors](https://discourse.julialang.org/t/small-vectors/97121)

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**Author:** [@olynch](https://discourse.julialang.org/u/olynch)\
**Replies:** 19\
**Last updated:** [November 13, 2024, 6:45pm UTC](https://discourse.julialang.org/t/small-vectors/97121 "2024-11-13T18:45:29Z")

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Rust has a smallvec package, which behaves like a vector except it stores the first n elements inline to the struct. Thus, there’s no allocation as long as you stay below n elements. Is there anything comparable to this …

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## [Specifying analytical jacobian in NonlinearProblem](https://discourse.julialang.org/t/specifying-analytical-jacobian-in-nonlinearproblem/112932)

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**Author:** [@askprash](https://discourse.julialang.org/u/askprash)\
**Replies:** 2\
**Last updated:** [April 14, 2024, 8:14pm UTC](https://discourse.julialang.org/t/specifying-analytical-jacobian-in-nonlinearproblem/112932 "2024-04-14T20:14:54Z")

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Hi! I’m new to using NonlinearSolve.jl and trying to understand how to provide an analytical jacobian to the problem. I realize that this is unnecessary if we have autodiff in the mix since that will be enough - but in c…

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## [Turing - "Automatic" Non-Centered Distribution Types](https://discourse.julialang.org/t/turing-automatic-non-centered-distribution-types/122598)

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**Author:** [@farr](https://discourse.julialang.org/u/farr)\
**Replies:** 0\
**Last updated:** [November 13, 2024, 3:52pm UTC](https://discourse.julialang.org/t/turing-automatic-non-centered-distribution-types/122598 "2024-11-13T15:52:28Z")

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Hi Folks, I experimented a bit today with some “automatic” non-centered Normal distributions this morning, and I think I have something that works quite well. Many experts know about the trick to replace mu ~ \<mu prio…

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