# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=147

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**Page:** 148

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## ["Warning: Instability detected. Aborting" while using lyapunovspectrum](https://discourse.julialang.org/t/warning-instability-detected-aborting-while-using-lyapunovspectrum/107536)

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**Author:** [@Daniel\_Montesinos\_Ca](https://discourse.julialang.org/u/Daniel_Montesinos_Ca)\
**Replies:** 7\
**Last updated:** [December 13, 2023, 7:15pm UTC](https://discourse.julialang.org/t/warning-instability-detected-aborting-while-using-lyapunovspectrum/107536 "2023-12-13T19:15:30Z")

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Hey, I’m trying to study the lyapunov spectrum for a 4D dynamical system using the lyapunovspectrum function from DynamicalSystem.jl but depending on the parameters I get “Warning: Instability detected. Aborting” and I …

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## [How does ModelingToolkit use bounds metadata?](https://discourse.julialang.org/t/how-does-modelingtoolkit-use-bounds-metadata/81487)

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**Author:** [@jedforrest](https://discourse.julialang.org/u/jedforrest)\
**Replies:** 17\
**Last updated:** [December 13, 2023, 5:18pm UTC](https://discourse.julialang.org/t/how-does-modelingtoolkit-use-bounds-metadata/81487 "2023-12-13T17:18:24Z")

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Hi all, What is the purpose of the bounds symbolic metadata in ModelingToolkit? When I add bounds to x in the following code, I would at first expect the solution for x to be limited between 0 and 2, but this doesn’t s…

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## [RE: Weighted Statistics with Missings](https://discourse.julialang.org/t/re-weighted-statistics-with-missings/107502)

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**Author:** [@gaspardelanuit](https://discourse.julialang.org/u/gaspardelanuit)\
**Replies:** 19\
**Last updated:** [December 13, 2023, 4:51pm UTC](https://discourse.julialang.org/t/re-weighted-statistics-with-missings/107502 "2023-12-13T16:51:34Z")

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There was a post on this topic a few years ago. I ran into this recently and thought this would be occasion to mention it again. I have not found an idiomatic way to solve the problem and from discussions of how to imp…

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## [JuliaSimModelOptimiser, UDEs, network and model connection](https://discourse.julialang.org/t/juliasimmodeloptimiser-udes-network-and-model-connection/107569)

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**Author:** [@rpex](https://discourse.julialang.org/u/rpex)\
**Replies:** 1\
**Last updated:** [December 13, 2023, 3:24pm UTC](https://discourse.julialang.org/t/juliasimmodeloptimiser-udes-network-and-model-connection/107569 "2023-12-13T15:24:32Z")

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When I use Neural Automated Model Discovery for Autocompleting Models with Prior Structural Information from JuliaSimModelOptimiser. How is the neural network connected with the incomplete model? Is it: \\frac{d states}…

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## [Accurate derivative for tanh](https://discourse.julialang.org/t/accurate-derivative-for-tanh/107568)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 13\
**Last updated:** [December 13, 2023, 2:43pm UTC](https://discourse.julialang.org/t/accurate-derivative-for-tanh/107568 "2023-12-13T14:43:45Z")

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When debugging a computation, I found that the derivative of tanh as defined in DiffRules.jl suffers from catastrophic cancellation for pretty mild values (eg outside 20 in absolute value, examples below). I propose a s…

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## [How to put labels for arrows?](https://discourse.julialang.org/t/how-to-put-labels-for-arrows/107524)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 1\
**Last updated:** [December 12, 2023, 10:48pm UTC](https://discourse.julialang.org/t/how-to-put-labels-for-arrows/107524 "2023-12-12T22:48:13Z")

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I simply want to recreate smth like here: Arrows with labels: on the sides or on the tops.

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## [Is there a DataFrame that can be memory mapped to a file?](https://discourse.julialang.org/t/is-there-a-dataframe-that-can-be-memory-mapped-to-a-file/96926)

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**Author:** [@ktdq](https://discourse.julialang.org/u/ktdq)\
**Replies:** 7\
**Last updated:** [December 13, 2023, 10:35am UTC](https://discourse.julialang.org/t/is-there-a-dataframe-that-can-be-memory-mapped-to-a-file/96926 "2023-12-13T10:35:23Z")

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Just saw Make loading weights 10-100x faster on Hacker News Is there something equivalent in Julia? Is there a way to store DataFrame in a file so it loads instantly via mmap?

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## [How can I extend a GridPosition?](https://discourse.julialang.org/t/how-can-i-extend-a-gridposition/107527)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 2\
**Last updated:** [December 13, 2023, 9:13am UTC](https://discourse.julialang.org/t/how-can-i-extend-a-gridposition/107527 "2023-12-13T09:13:12Z")

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I have plot with multiple subplots, each of it is a GridPosition. f = Figure(resolution = (1200, 1400)) ga = f\[1, 1\] gc = f\[2, 1\] ge = f\[3, 1\] gg = f\[4, 1\] gb = f\[1, 2\] gd = f\[2, 2\] gf = f\[3,…

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## [How to compute the bipartite entanglement entropy with the first site as the subsystem us orthogonalize？？](https://discourse.julialang.org/t/how-to-compute-the-bipartite-entanglement-entropy-with-the-first-site-as-the-subsystem-us-orthogonalize/107509)

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**Author:** [@zipeilee](https://discourse.julialang.org/u/zipeilee)\
**Replies:** 3\
**Last updated:** [December 13, 2023, 3:17am UTC](https://discourse.julialang.org/t/how-to-compute-the-bipartite-entanglement-entropy-with-the-first-site-as-the-subsystem-us-orthogonalize/107509 "2023-12-13T03:17:54Z")

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I’m new to tensor networks. I understand that for an MPS state in the form of orthogonalization, the bipartite entanglement entropy of a subsystem is center site’s singular spectrum. I’ve found useful code on ITensors.jl…

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## [How to link axes in a Makie figure?](https://discourse.julialang.org/t/how-to-link-axes-in-a-makie-figure/62622)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 7\
**Last updated:** [December 13, 2023, 1:26am UTC](https://discourse.julialang.org/t/how-to-link-axes-in-a-makie-figure/62622 "2023-12-13T01:26:15Z")

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Suppose I have a figure with multiple subfigures: using GLMakie fig = Figure() scatter(fig\[1,1\], rand(10)) scatter(fig\[1,2\], rand(10)) How to link all axes in the figure? I am aware of linkaxes! but it expects axes ob…

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## [Flux.update! not working with custom AbstractArray](https://discourse.julialang.org/t/flux-update-not-working-with-custom-abstractarray/107530)

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**Author:** [@nelslind](https://discourse.julialang.org/u/nelslind)\
**Replies:** 1\
**Last updated:** [December 12, 2023, 11:13pm UTC](https://discourse.julialang.org/t/flux-update-not-working-with-custom-abstractarray/107530 "2023-12-12T23:13:37Z")

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When building a model using custom structs that are subtypes of AbstractArray, Flux.update! cannot update the model. For my use case, it is particularly convenient to do computations using these custom structs. Is there…

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## [Direct Forward Sensitivity Analysis of ODEs in ModelingToolkit.jl for a Subset of Parameters](https://discourse.julialang.org/t/direct-forward-sensitivity-analysis-of-odes-in-modelingtoolkit-jl-for-a-subset-of-parameters/104903)

<div class="topic-metadata">

**Author:** [@Can\_Bozdogan](https://discourse.julialang.org/u/Can_Bozdogan)\
**Replies:** 4\
**Last updated:** [December 12, 2023, 10:00pm UTC](https://discourse.julialang.org/t/direct-forward-sensitivity-analysis-of-odes-in-modelingtoolkit-jl-for-a-subset-of-parameters/104903 "2023-12-12T22:00:49Z")

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Hello, I am working on a project that involves setting up and solving an ODE system. I’ve defined my ODE system using ModelingToolkit.jl and not as a function. My ODE system has many parameters, and I’m interested in pe…

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## [Can ModelingToolkit be used for simulating fluid flow including fluid properties?](https://discourse.julialang.org/t/can-modelingtoolkit-be-used-for-simulating-fluid-flow-including-fluid-properties/107298)

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**Author:** [@NikoBiele](https://discourse.julialang.org/u/NikoBiele)\
**Replies:** 6\
**Last updated:** [December 12, 2023, 5:39pm UTC](https://discourse.julialang.org/t/can-modelingtoolkit-be-used-for-simulating-fluid-flow-including-fluid-properties/107298 "2023-12-12T17:39:56Z")

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Hi all, I am huge fan of Julia, and I used it for my Master’s thesis where I made a large dynamic model of a two-stage heat pump, including all of the fluid properties (via CoolProp.jl), such as: Temperature, pressure, …

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## [AMDGPU: Very aggressive allocation? And what tools to monitor vram usage?](https://discourse.julialang.org/t/amdgpu-very-aggressive-allocation-and-what-tools-to-monitor-vram-usage/107458)

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**Author:** [@Tetrakai](https://discourse.julialang.org/u/Tetrakai)\
**Replies:** 15\
**Last updated:** [December 12, 2023, 5:22pm UTC](https://discourse.julialang.org/t/amdgpu-very-aggressive-allocation-and-what-tools-to-monitor-vram-usage/107458 "2023-12-12T17:22:35Z")

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So I was able to train my first network outside of a tutorial. It was very satisfying to get the 100-1000x improvement over cpu. I tried using multiple linux tools to monitor vram (that apparently get their info from th…

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## [Support for arrow c interface](https://discourse.julialang.org/t/support-for-arrow-c-interface/107505)

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**Author:** [@rdavis120](https://discourse.julialang.org/u/rdavis120)\
**Replies:** 1\
**Last updated:** [December 12, 2023, 4:41pm UTC](https://discourse.julialang.org/t/support-for-arrow-c-interface/107505 "2023-12-12T16:41:25Z")

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In the 2023 Presentation Working with DataFrames (Part 2), the arrow C interface is mentioned by @quinnj. I think Julia is the only language that currently doesn’t support the c interface, but there has been a pull reque…

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## [Type unstable gradients in Zygote (@code\_warntype)](https://discourse.julialang.org/t/type-unstable-gradients-in-zygote-code-warntype/107279)

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**Author:** [@Iris\_Allevi](https://discourse.julialang.org/u/Iris_Allevi)\
**Replies:** 5\
**Last updated:** [December 12, 2023, 4:31pm UTC](https://discourse.julialang.org/t/type-unstable-gradients-in-zygote-code-warntype/107279 "2023-12-12T16:31:04Z")

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Hello there, I’m trying to write efficient code for custom automatic differentiation in Julia. I noticed that even for a simple case, Zygote gives type unstable gradients. Can you please help me understand why? Here’s…

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## [JuliaSimModelOptimiser get calibration results](https://discourse.julialang.org/t/juliasimmodeloptimiser-get-calibration-results/107503)

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**Author:** [@rpex](https://discourse.julialang.org/u/rpex)\
**Replies:** 1\
**Last updated:** [December 12, 2023, 3:33pm UTC](https://discourse.julialang.org/t/juliasimmodeloptimiser-get-calibration-results/107503 "2023-12-12T15:33:10Z")

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Can JuliaSimModelOptimiser.jl topics be asked here? I define a search space and create an JuliaSimModelOptimizer.InverseProblem. Then I calibrate my search space to data and get a JuliaSimModelOptimizer.CalibrateResult. …

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## [Setting up free final time in JuMP optimization](https://discourse.julialang.org/t/setting-up-free-final-time-in-jump-optimization/107302)

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**Author:** [@pluie](https://discourse.julialang.org/u/pluie)\
**Replies:** 8\
**Last updated:** [December 12, 2023, 2:11pm UTC](https://discourse.julialang.org/t/setting-up-free-final-time-in-jump-optimization/107302 "2023-12-12T14:11:07Z")

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I am trying to set up a nonlinear optimization problem using JuMP. I have been referencing some examples included in its documentation. The problem I am trying to set up is similar to the Rocket Control example: Rocket C…

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## [Use ReverseDiff.jl in JuMP](https://discourse.julialang.org/t/use-reversediff-jl-in-jump/107469)

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**Author:** [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Replies:** 7\
**Last updated:** [December 12, 2023, 10:10am UTC](https://discourse.julialang.org/t/use-reversediff-jl-in-jump/107469 "2023-12-12T10:10:54Z")

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Is it possible to use ReverseDiff.jl in JuMP.jl instead of ForwardDiff.jl. I am not seeing the desired speedup in JuMP when I’m using ForwardDiff.jl

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## [Scalar indexing using broadcast notation?](https://discourse.julialang.org/t/scalar-indexing-using-broadcast-notation/107471)

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**Author:** [@nihil](https://discourse.julialang.org/u/nihil)\
**Replies:** 4\
**Last updated:** [December 12, 2023, 2:39am UTC](https://discourse.julialang.org/t/scalar-indexing-using-broadcast-notation/107471 "2023-12-12T02:39:52Z")

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I want to convert this to broadcast . notation indices = shuffle(\[(i, j) for i in 1:height for j in 1:width\]) for (i, j) in indices img\[i, j\] = sum(img .- (function.((img .- img\[i, j\])…

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## [Incorrect filling in polar plot using fillrange](https://discourse.julialang.org/t/incorrect-filling-in-polar-plot-using-fillrange/107390)

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**Author:** [@TheBigZet](https://discourse.julialang.org/u/TheBigZet)\
**Replies:** 0\
**Last updated:** [December 10, 2023, 11:00pm UTC](https://discourse.julialang.org/t/incorrect-filling-in-polar-plot-using-fillrange/107390 "2023-12-10T23:00:40Z")

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I am trying to create a polar plot, with hatched area between the series and a constant value. I’ve managed to do so with this code: x1 = collect(range(0, π, length = 100)) x2 = collect(range(π, 0, length = 100)) y1 =…

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## [Two arrows](https://discourse.julialang.org/t/two-arrows/107453)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 4\
**Last updated:** [December 11, 2023, 4:51pm UTC](https://discourse.julialang.org/t/two-arrows/107453 "2023-12-11T16:51:55Z")

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Can anyone please show how to create a simplest plot with two arrows using Makie.arrow? Documentation here arrows · Makie is written at really advance level.

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## [Problem with ForwardDiff not letting me update variable "d"](https://discourse.julialang.org/t/problem-with-forwarddiff-not-letting-me-update-variable-d/107417)

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**Author:** [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Replies:** 7\
**Last updated:** [December 11, 2023, 2:27pm UTC](https://discourse.julialang.org/t/problem-with-forwarddiff-not-letting-me-update-variable-d/107417 "2023-12-11T14:27:10Z")

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Here is a watered down version of code I am using a = zeros(2393) a = findall(x -\> x == 0, a) b = zeros(293) e = rand(2979) l = zeros(137,293) g = ones(137,293) h = rand(137,170) function dummy(e::T...) where {T}…

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## [Is it expected that a zero-one variable may have a non-integer value after an optimal solution is found?](https://discourse.julialang.org/t/is-it-expected-that-a-zero-one-variable-may-have-a-non-integer-value-after-an-optimal-solution-is-found/107430)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 5\
**Last updated:** [December 11, 2023, 12:37pm UTC](https://discourse.julialang.org/t/is-it-expected-that-a-zero-one-variable-may-have-a-non-integer-value-after-an-optimal-solution-is-found/107430 "2023-12-11T12:37:37Z")

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I formulate a mathematical optimization (MIQCP) problem with MathOptInterface.jl and solve it with Gurobi.jl. Certain variables in my problem are constrained (with MOI.add\_constrained\_variables(optimizer, \[MOI.ZeroOne() …

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## [Gurobi AddGenConstrPoly() in JuMP](https://discourse.julialang.org/t/gurobi-addgenconstrpoly-in-jump/107123)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 7\
**Last updated:** [December 11, 2023, 5:17am UTC](https://discourse.julialang.org/t/gurobi-addgenconstrpoly-in-jump/107123 "2023-12-11T05:17:23Z")

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Hi All, Can we code GRBModel.AddGenConstrPoly() constraint available in gurobi directly in JuMP. The MINLP is solved using Juniper. we want to try Gurobi for this.

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## [All positive eigen values but false in isposdef?](https://discourse.julialang.org/t/all-positive-eigen-values-but-false-in-isposdef/107393)

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**Author:** [@Wooheon](https://discourse.julialang.org/u/Wooheon)\
**Replies:** 2\
**Last updated:** [December 11, 2023, 1:25am UTC](https://discourse.julialang.org/t/all-positive-eigen-values-but-false-in-isposdef/107393 "2023-12-11T01:25:28Z")

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Hello, I was curious about my Julia code spitting out negative variance for some variations in sandwich form vcov matrices (in Fixed Effects, clustering etc.). Let’s say my matrix of control variables, X. I found out t…

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## [Understanding the behaviour of Butterworth filter in DSP](https://discourse.julialang.org/t/understanding-the-behaviour-of-butterworth-filter-in-dsp/107396)

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**Author:** [@PeX](https://discourse.julialang.org/u/PeX)\
**Replies:** 3\
**Last updated:** [December 11, 2023, 12:57am UTC](https://discourse.julialang.org/t/understanding-the-behaviour-of-butterworth-filter-in-dsp/107396 "2023-12-11T00:57:52Z")

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Hi all, I’m using a highpass filter to isolate the oscillations from the trend in my signal. The filter I use for my time series signal is: response = Highpass((𝑓/1); fs) design = Butterworth(2) filtered = filt(digital…

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## [Minimisation with equality constraints](https://discourse.julialang.org/t/minimisation-with-equality-constraints/107358)

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**Author:** [@eveningsilverfox](https://discourse.julialang.org/u/eveningsilverfox)\
**Replies:** 5\
**Last updated:** [December 10, 2023, 9:13pm UTC](https://discourse.julialang.org/t/minimisation-with-equality-constraints/107358 "2023-12-10T21:13:06Z")

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I am trying a constrained minimisation with equality constraints. using LinearAlgebra using Optimization, OptimizationMOI, AmplNLWriter, Ipopt\_jll function objectivehelp(N) car = rand(N) .+ 1; sar = rand(N); r…

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## [How to convert an ODESystem to NonlinearSystem?](https://discourse.julialang.org/t/how-to-convert-an-odesystem-to-nonlinearsystem/91079)

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**Author:** [@wangyunyueyueniao](https://discourse.julialang.org/u/wangyunyueyueniao)\
**Replies:** 8\
**Last updated:** [December 10, 2023, 2:31pm UTC](https://discourse.julialang.org/t/how-to-convert-an-odesystem-to-nonlinearsystem/91079 "2023-12-10T14:31:46Z")

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I know there is a “convert\_system” function which can convert a “NonlinearSystem” to an “ODESystem”. Can we do it backwards? So that we can have both steady-state and dynamic simulation with a single code base.

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## [Can this type of integro-differential equation be solved somewhere?](https://discourse.julialang.org/t/can-this-type-of-integro-differential-equation-be-solved-somewhere/107286)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 2\
**Last updated:** [December 10, 2023, 1:01pm UTC](https://discourse.julialang.org/t/can-this-type-of-integro-differential-equation-be-solved-somewhere/107286 "2023-12-10T13:01:24Z")

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Hey, I admit that I am a novice in differential equations solving, this problem came out of completely somthing else… I want to solve an equation that has the following form : S(t) = \\exp(- H(t)) \\partial H(t) = F(t,…

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