# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=207

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**Page:** 208

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## [Is it possible to see a solution related to upper bound?](https://discourse.julialang.org/t/is-it-possible-to-see-a-solution-related-to-upper-bound/95735)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 5\
**Last updated:** [March 16, 2023, 9:12am UTC](https://discourse.julialang.org/t/is-it-possible-to-see-a-solution-related-to-upper-bound/95735 "2023-03-16T09:12:53Z")

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Hi guys, I use CPLEX as an optimizer and JuMP apackage. I have a big IP that needs at least 2hours to generate a soultion. I wonder is there a way to stop it early? when running a model that takes a long time to give y…

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## [\[Makie\] Parallel Record](https://discourse.julialang.org/t/makie-parallel-record/96162)

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**Author:** [@AstroBarker](https://discourse.julialang.org/u/AstroBarker)\
**Replies:** 1\
**Last updated:** [March 16, 2023, 3:30am UTC](https://discourse.julialang.org/t/makie-parallel-record/96162 "2023-03-16T03:30:27Z")

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Hey folks. I am using Makie to create animations of 2D or 3D data. I am wondering if there is a convenient way to use threads to parallelize the record feature, similar to using a threaded map/call in python?

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## [Sort array based on another array?](https://discourse.julialang.org/t/sort-array-based-on-another-array/26854)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 14\
**Last updated:** [March 16, 2023, 2:42am UTC](https://discourse.julialang.org/t/sort-array-based-on-another-array/26854 "2023-03-16T02:42:43Z")

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Hello I am post-processing some particle simulation data and for an example I would get the following two arrays: Rhop\_vec\[50\] 125749-element Array{Float32,1}: 1007.7992 1014.8219 1011.84064 1019.48114 1011.2265 …

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## [Estimating parameters of ODEs leads to instability](https://discourse.julialang.org/t/estimating-parameters-of-odes-leads-to-instability/96149)

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**Author:** [@stepanoslejsek](https://discourse.julialang.org/u/stepanoslejsek)\
**Replies:** 1\
**Last updated:** [March 15, 2023, 11:34pm UTC](https://discourse.julialang.org/t/estimating-parameters-of-odes-leads-to-instability/96149 "2023-03-15T23:34:31Z")

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I have a system of ODEs in a form of: Dt(θ) ~ θ̇ Dt(θ̇) ~ a₁ \* θ̇ + a₂ \* sin(ψ) + a₃ \* ψ̇ + a₄ \* u(t) Dt(ψ) ~ ψ̇ Dt(ψ̇) ~ a₅ \* θ̇ + a₆ \* sin(ψ) + a₇ \* ψ̇ + a₈ \* u(t) where a₁,…,a₈ are parameters to be estimated…

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## [Trying to use FileFormats with JuMP](https://discourse.julialang.org/t/trying-to-use-fileformats-with-jump/96144)

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**Author:** [@shakedregev](https://discourse.julialang.org/u/shakedregev)\
**Replies:** 1\
**Last updated:** [March 15, 2023, 7:35pm UTC](https://discourse.julialang.org/t/trying-to-use-fileformats-with-jump/96144 "2023-03-15T19:35:17Z")

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Following the example here, I’m trying to use JuMP to write a model to a file. src = JuMP.Model(Clarabel.Optimizer) filename = "my\_model.lp" dest = FileFormats.Model(filename = filename) MOI.copy\_to(dest, src) MOI.write…

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## [Installing Mosek Error for JuMP](https://discourse.julialang.org/t/installing-mosek-error-for-jump/96083)

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**Author:** [@A\_M](https://discourse.julialang.org/u/A_M)\
**Replies:** 15\
**Last updated:** [March 15, 2023, 6:35pm UTC](https://discourse.julialang.org/t/installing-mosek-error-for-jump/96083 "2023-03-15T18:35:51Z")

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I used to use something like this to build a docker, but suddenly I started getting this error FROM ubuntu:18.04 as base RUN apt-get -y update; apt-get -y install curl ENV JULIA\_PATH /julia ENV PATH "$JULIA\_PATH/bin:$PA…

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## [Saving a model built with Transformers.jl](https://discourse.julialang.org/t/saving-a-model-built-with-transformers-jl/96132)

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**Author:** [@gemuesi](https://discourse.julialang.org/u/gemuesi)\
**Replies:** 6\
**Last updated:** [March 15, 2023, 1:48pm UTC](https://discourse.julialang.org/t/saving-a-model-built-with-transformers-jl/96132 "2023-03-15T13:48:28Z")

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Hi there, I am pretty new to anything related to this topic in general, but I found Flux to be quite accessible and wanted to have a look at the Transformers.jl package as well. I’ve been playing around with the copy ta…

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## [Slow model construction in JuMP](https://discourse.julialang.org/t/slow-model-construction-in-jump/95455)

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**Author:** [@jacob-roth](https://discourse.julialang.org/u/jacob-roth)\
**Replies:** 14\
**Last updated:** [March 14, 2023, 10:28pm UTC](https://discourse.julialang.org/t/slow-model-construction-in-jump/95455 "2023-03-14T22:28:03Z")

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I find that when I am modeling a problem in JuMP, the model construction takes a long time. My first thought was that maybe I am writing inefficient code, and I was wondering: if there might be any quick fixes to my Ju…

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## [Error with HiGHS independent parallel solves](https://discourse.julialang.org/t/error-with-highs-independent-parallel-solves/96048)

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**Author:** [@Naunet](https://discourse.julialang.org/u/Naunet)\
**Replies:** 1\
**Last updated:** [March 14, 2023, 9:33pm UTC](https://discourse.julialang.org/t/error-with-highs-independent-parallel-solves/96048 "2023-03-14T21:33:04Z")

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A parallel example using HiGHS was recently published here : Parallelism · JuMP However, when I change the model used to something that requires several iterations instead of just presolve it prints a bunch of Iteration…

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## [Matrix-Free/Function-Only Linear Solves](https://discourse.julialang.org/t/matrix-free-function-only-linear-solves/95411)

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**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 5\
**Last updated:** [March 14, 2023, 7:26pm UTC](https://discourse.julialang.org/t/matrix-free-function-only-linear-solves/95411 "2023-03-14T19:26:08Z")

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Suppose I want to solve a system of equations A\*x = b, and I have a function A\_func such that A\_func(x) = A\*x. How could I go about solving the system of equations without constructing the matrix A? I could construct th…

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## [Use of update!() in RXInfer to handle multiple iterations](https://discourse.julialang.org/t/use-of-update-in-rxinfer-to-handle-multiple-iterations/95709)

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**Author:** [@John\_Boik](https://discourse.julialang.org/u/John_Boik)\
**Replies:** 12\
**Last updated:** [March 14, 2023, 4:35pm UTC](https://discourse.julialang.org/t/use-of-update-in-rxinfer-to-handle-multiple-iterations/95709 "2023-03-14T16:35:05Z")

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I am trying to implement the van de Laar chance constraint model in RXInfer, and as a warm-up I have implemented the reference model from the same paper. Code is included at the end of this post that produces an output g…

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## [Run stochastic models in parallel in for loop](https://discourse.julialang.org/t/run-stochastic-models-in-parallel-in-for-loop/96052)

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**Author:** [@Pablo\_Flores](https://discourse.julialang.org/u/Pablo_Flores)\
**Replies:** 2\
**Last updated:** [March 14, 2023, 2:33pm UTC](https://discourse.julialang.org/t/run-stochastic-models-in-parallel-in-for-loop/96052 "2023-03-14T14:33:34Z")

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Hi everyone, I’m working in my master’s thesis and trying to lower the running time that my code has, by parallelizing the optimization of different models created by scenarios, to then calculate some other values after…

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## [Lux initialization](https://discourse.julialang.org/t/lux-initialization/96049)

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**Author:** [@Stefano\_Giampiccolo](https://discourse.julialang.org/u/Stefano_Giampiccolo)\
**Replies:** 2\
**Last updated:** [March 14, 2023, 12:22pm UTC](https://discourse.julialang.org/t/lux-initialization/96049 "2023-03-14T12:22:59Z")

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Hello everyone, I apologize for the probably naive question, but if I wanted to initialize the layer parameters with glorot\_uniform in Lux with a gain smaller than the default, how do I then obtain the parameters and sta…

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## [BioJulia Fastx import long{4}](https://discourse.julialang.org/t/biojulia-fastx-import-long-4/78098)

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**Author:** [@Jdbeck66](https://discourse.julialang.org/u/Jdbeck66)\
**Replies:** 1\
**Last updated:** [March 14, 2023, 4:19am UTC](https://discourse.julialang.org/t/biojulia-fastx-import-long-4/78098 "2023-03-14T04:19:35Z")

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I have a fast file that I loaded with FASTX and it seems that the data is stored as a LongDNA{4}. There are no ambiguities in the reads and I’d like to work with them as 2 bit sequences but I get an error when I try to …

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## [Issue with memoization with JuMP for NLP when adding @NLObjective](https://discourse.julialang.org/t/issue-with-memoization-with-jump-for-nlp-when-adding-nlobjective/96033)

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**Author:** [@YuriS](https://discourse.julialang.org/u/YuriS)\
**Replies:** 3\
**Last updated:** [March 14, 2023, 2:36am UTC](https://discourse.julialang.org/t/issue-with-memoization-with-jump-for-nlp-when-adding-nlobjective/96033 "2023-03-14T02:36:59Z")

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Hello, I’ve been following this tutorial from JuMP on memorization for NLP via JuMP with user-defined, vector-output functions One issue I am having currently is that once I have a memorized function registered to the m…

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## [How to obtain dual variables (shadow price) for a set of constraints](https://discourse.julialang.org/t/how-to-obtain-dual-variables-shadow-price-for-a-set-of-constraints/95986)

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**Author:** [@kevinqiao](https://discourse.julialang.org/u/kevinqiao)\
**Replies:** 4\
**Last updated:** [March 14, 2023, 1:48am UTC](https://discourse.julialang.org/t/how-to-obtain-dual-variables-shadow-price-for-a-set-of-constraints/95986 "2023-03-14T01:48:46Z")

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Hello, I have time-related constraints and I modeled it as for time in 1:nTime @constraint(model, a\[time\] + b\[time\] == c\[time\], base\_name = "cons" end The model is solved and I want to obtain the dual variables, …

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## [Recommend a parsing library for LibPQ.jl?](https://discourse.julialang.org/t/recommend-a-parsing-library-for-libpq-jl/96023)

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**Author:** [@iamed2](https://discourse.julialang.org/u/iamed2)\
**Replies:** 1\
**Last updated:** [March 13, 2023, 10:14pm UTC](https://discourse.julialang.org/t/recommend-a-parsing-library-for-libpq-jl/96023 "2023-03-13T22:14:47Z")

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I’m looking to improve the parsing code in LibPQ and expand support for more data types. PCRE2 is expensive and heavyweight, but it’s a challenge to write each parser from scratch and I don’t want to reinvent the wheel. …

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## [Multiple normal distributions in one 3D plot](https://discourse.julialang.org/t/multiple-normal-distributions-in-one-3d-plot/95969)

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**Author:** [@Mouad](https://discourse.julialang.org/u/Mouad)\
**Replies:** 3\
**Last updated:** [March 13, 2023, 10:02pm UTC](https://discourse.julialang.org/t/multiple-normal-distributions-in-one-3d-plot/95969 "2023-03-13T22:02:13Z")

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Hello, I am trying to plot multiple normal distributions centered around the same mean with different variations in GLmakie. Pretty much this picture (generated in wolfram alpha): Hopefully, also animate it by making…

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## [Nonlinear optimization using JuMP, The solver does not support nonlinear problems (i.e., NLobjective and NLconstraint)](https://discourse.julialang.org/t/nonlinear-optimization-using-jump-the-solver-does-not-support-nonlinear-problems-i-e-nlobjective-and-nlconstraint/95978)

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**Author:** [@mosby](https://discourse.julialang.org/u/mosby)\
**Replies:** 10\
**Last updated:** [March 13, 2023, 7:30pm UTC](https://discourse.julialang.org/t/nonlinear-optimization-using-jump-the-solver-does-not-support-nonlinear-problems-i-e-nlobjective-and-nlconstraint/95978 "2023-03-13T19:30:14Z")

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I am solving a nonlinear optimization problem using Mosek, I am running the following script model = Model(Mosek.Optimizer) @variable(model, y\[1:n\]) @NLconstraint(model, sum((Ay-b)\[i\]^4 for i=1:m) \<= 1.0) # The constr…

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## [LibPQ copy error when field of the data frame contains comma](https://discourse.julialang.org/t/libpq-copy-error-when-field-of-the-data-frame-contains-comma/94058)

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**Author:** [@ultratrader](https://discourse.julialang.org/u/ultratrader)\
**Replies:** 2\
**Last updated:** [March 13, 2023, 6:11pm UTC](https://discourse.julialang.org/t/libpq-copy-error-when-field-of-the-data-frame-contains-comma/94058 "2023-03-13T18:11:56Z")

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I am trying to load data from data frame to postgresql using LibPQ.jl. it work quite fast until it reachs field that contains “,” such as “Oil, Gas & Coal” and throw an error: \[error | LibPQ\]: BadCopyFileFormat: ERROR: …

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## [How to specify colors from a colormap to use in a theme in makie?](https://discourse.julialang.org/t/how-to-specify-colors-from-a-colormap-to-use-in-a-theme-in-makie/95981)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 8\
**Last updated:** [March 13, 2023, 5:49pm UTC](https://discourse.julialang.org/t/how-to-specify-colors-from-a-colormap-to-use-in-a-theme-in-makie/95981 "2023-03-13T17:49:44Z")

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Hello, I’d like to be able to specify a colormap, say Dark2, to be used as the automatic colors in the lines plot type. Reading around it seems like I should be using the theming system to do it. Unfortunately I’ve not …

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## [How do you use \`Plots.jl\`'s \`mesh3d\` in place of matplotlib's \`plot\_trisurf\`?](https://discourse.julialang.org/t/how-do-you-use-plots-jl-s-mesh3d-in-place-of-matplotlibs-plot-trisurf/96016)

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**Author:** [@tgross35](https://discourse.julialang.org/u/tgross35)\
**Replies:** 0\
**Last updated:** [March 13, 2023, 5:39pm UTC](https://discourse.julialang.org/t/how-do-you-use-plots-jl-s-mesh3d-in-place-of-matplotlibs-plot-trisurf/96016 "2023-03-13T17:39:41Z")

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Hello everyone, I’m trying to use a mesh3d as a drop in for plot\_trisurf, but am struggling to get the same functionality. The difference looks like this: plot\_trisurf(X, Y, Z) mesh3d(X, Y, Z, connections=(i, j, k)) A…

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## [On-the-flight kernel density estimation?](https://discourse.julialang.org/t/on-the-flight-kernel-density-estimation/95817)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 15\
**Last updated:** [March 13, 2023, 5:12pm UTC](https://discourse.julialang.org/t/on-the-flight-kernel-density-estimation/95817 "2023-03-13T17:12:03Z")

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I have the following type of problem: imagine a Monte-Carlo simulation generating some data, and I want to estimate the density function for that simulation. I cannot store the data for each Monte-Carlos step, which woul…

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## [Flux Transformer Out of Memory](https://discourse.julialang.org/t/flux-transformer-out-of-memory/95922)

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**Author:** [@Gadersd](https://discourse.julialang.org/u/Gadersd)\
**Replies:** 25\
**Last updated:** [March 13, 2023, 2:36pm UTC](https://discourse.julialang.org/t/flux-transformer-out-of-memory/95922 "2023-03-13T14:36:13Z")

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I started off with PyTorch, but after hearing about Julia Flux I decided to try it out to reap the promised elegance and ease of use. I ported my transformer implementation to Julia and verified that the outputs match th…

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## [Training a neural ode with unknow time span](https://discourse.julialang.org/t/training-a-neural-ode-with-unknow-time-span/95992)

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**Author:** [@kaido975](https://discourse.julialang.org/u/kaido975)\
**Replies:** 4\
**Last updated:** [March 13, 2023, 2:48pm UTC](https://discourse.julialang.org/t/training-a-neural-ode-with-unknow-time-span/95992 "2023-03-13T14:48:03Z")

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I am trying to train a neural ode with a start time = 0 and an unknown end time. Here is the working code. using Lux, DiffEqFlux, DifferentialEquations, Optimization, OptimizationOptimJL, Random, Plots, ComponentArrays…

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## [Fixedpoints DynamicalSystems.jl](https://discourse.julialang.org/t/fixedpoints-dynamicalsystems-jl/96004)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [March 13, 2023, 2:05pm UTC](https://discourse.julialang.org/t/fixedpoints-dynamicalsystems-jl/96004 "2023-03-13T14:05:47Z")

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Hello, how can i automaticaly calculate Jacobian? I have next system and manual calculate Jacobian is hard Code: function TM(u, p, t) U(y) = p\[8\] + p\[9\] / ( 1.0 + exp( -50.0 \* (y - p\[7\]) ) ) σ(x) = 1.0 / ( 1…

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## [Is accumulate() with '+' producing the wrong results?](https://discourse.julialang.org/t/is-accumulate-with-producing-the-wrong-results/95952)

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**Author:** [@P570](https://discourse.julialang.org/u/P570)\
**Replies:** 1\
**Last updated:** [March 13, 2023, 11:06am UTC](https://discourse.julialang.org/t/is-accumulate-with-producing-the-wrong-results/95952 "2023-03-13T11:06:25Z")

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Hi, I lately started experimenting a bit with CUDA and was doing some exploratory work through the REPL. I was doing some addition tests with accumulate() and reduce() when I stumbled on what seems to be an issue with …

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## [Advice for optimising code for GPU](https://discourse.julialang.org/t/advice-for-optimising-code-for-gpu/95939)

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**Author:** [@maaaks](https://discourse.julialang.org/u/maaaks)\
**Replies:** 3\
**Last updated:** [March 13, 2023, 10:39am UTC](https://discourse.julialang.org/t/advice-for-optimising-code-for-gpu/95939 "2023-03-13T10:39:34Z")

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Hello! I have recently ported a matlab package to Julia (and found the process suprisingly straight forward), however I with to be able to execute it on the GPU as I with to use it as part of a loss function in an ML pr…

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## [Elongated scene](https://discourse.julialang.org/t/elongated-scene/95875)

<div class="topic-metadata">

**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [March 13, 2023, 6:01am UTC](https://discourse.julialang.org/t/elongated-scene/95875 "2023-03-13T06:01:00Z")

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Why i have elongated scene with code ts, tf = 1, 9000000 idx, idy, idz = 2, 1, 3 xl, yl, zl = labels3d(idx,idy, idz) GLMakie.activate!() f = Figure(resolution = (1200, 900)) ax = LScene(f\[1, 1\]) lines!(tr\[ts:tf, idx\], …

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## [Find homoclinic DifferentialEquations.jl, DynamicalSystems.jl](https://discourse.julialang.org/t/find-homoclinic-differentialequations-jl-dynamicalsystems-jl/95800)

<div class="topic-metadata">

**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 17\
**Last updated:** [March 13, 2023, 5:46am UTC](https://discourse.julialang.org/t/find-homoclinic-differentialequations-jl-dynamicalsystems-jl/95800 "2023-03-13T05:46:24Z")

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Hello, I’m trying to find a homoclinic orbit. To do this, I calculate a very long trajectory, and then calculate the minimum distance between all points of the trajectory and a fixed point. How can I optimize this? Frag…

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