# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=26

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 27

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## [Cannot fix \`nothing\` in summation](https://discourse.julialang.org/t/cannot-fix-nothing-in-summation/132507)

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**Author:** [@rgouveiamendes](https://discourse.julialang.org/u/rgouveiamendes)\
**Replies:** 7\
**Last updated:** [September 19, 2025, 2:04pm UTC](https://discourse.julialang.org/t/cannot-fix-nothing-in-summation/132507 "2025-09-19T14:04:40Z")

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Hello, I am trying to perform the following transformation on a DataFrame: @transform! df\_20\_P\_raw\[:data\] begin # Calculate the sum of the relevant columns, replacing missing values with 0 :pensions\_balance\_pro…

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## [How to extract solution when using Trixi.jl](https://discourse.julialang.org/t/how-to-extract-solution-when-using-trixi-jl/132512)

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**Author:** [@mra](https://discourse.julialang.org/u/mra)\
**Replies:** 3\
**Last updated:** [September 19, 2025, 1:41pm UTC](https://discourse.julialang.org/t/how-to-extract-solution-when-using-trixi-jl/132512 "2025-09-19T13:41:37Z")

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I have trouble extracting the solution in a format of points where each point stores (x, u) where x is the coordinate (position) and u is the value at that position. Even though I can extract the coordinates x and value…

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## [Solving the Boltzmann transport equation using Trixi.jl](https://discourse.julialang.org/t/solving-the-boltzmann-transport-equation-using-trixi-jl/132509)

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**Author:** [@drandran12](https://discourse.julialang.org/u/drandran12)\
**Replies:** 4\
**Last updated:** [September 19, 2025, 12:35pm UTC](https://discourse.julialang.org/t/solving-the-boltzmann-transport-equation-using-trixi-jl/132509 "2025-09-19T12:35:58Z")

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I need to solve the two spatial dimensional Boltzmann transport equation of the form: \\left\[\\partial\_t+\\vec{k} \\cdot \\vec{\\nabla}\_x-\\vec{\\nabla}\_x V \\cdot \\vec{\\nabla}\_k\\right\] n(\\vec{x}, t, \\vec{k})=-4 \\Gamma\_a \\int \\…

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## [@mtkmodel ODE Confusion, DiffEqParamEstim](https://discourse.julialang.org/t/mtkmodel-ode-confusion-diffeqparamestim/132228)

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**Author:** [@jdm204](https://discourse.julialang.org/u/jdm204)\
**Replies:** 1\
**Last updated:** [September 18, 2025, 11:37pm UTC](https://discourse.julialang.org/t/mtkmodel-ode-confusion-diffeqparamestim/132228 "2025-09-18T23:37:19Z")

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Apologies, I think I have a basic misunderstanding somewhere, I’ve been stuck for a few days. I’m struggling to understand how I should use @mtkmodel defined ODEs, I ran into the problem trying to use DiffEqParamEstim. I…

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## [Dynamically updating plots (heatmap) in Gtk4.jl and Gtk4Makie.jl](https://discourse.julialang.org/t/dynamically-updating-plots-heatmap-in-gtk4-jl-and-gtk4makie-jl/131653)

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**Author:** [@dopamine](https://discourse.julialang.org/u/dopamine)\
**Replies:** 1\
**Last updated:** [September 18, 2025, 1:56pm UTC](https://discourse.julialang.org/t/dynamically-updating-plots-heatmap-in-gtk4-jl-and-gtk4makie-jl/131653 "2025-09-18T13:56:13Z")

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I’ve been trying to set up a Makie plot (using GLMakie) inside a GtkFrame (Gtk4.jl) and update it programmatically on demand. I can make it work with CairoMakie, but currently trying to use GLMakie instead to minimize la…

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## [SteadyStateProblem solved result problem](https://discourse.julialang.org/t/steadystateproblem-solved-result-problem/88511)

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**Author:** [@hzgzh](https://discourse.julialang.org/u/hzgzh)\
**Replies:** 26\
**Last updated:** [September 18, 2025, 11:39am UTC](https://discourse.julialang.org/t/steadystateproblem-solved-result-problem/88511 "2025-09-18T11:39:39Z")

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My problem as code using ModelingToolkit @variables t x(t) # independent and dependent variables @parameters τ # parameters D = Differential(t) # define an operator for the differentiation w.r.t. time # your f…

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## [CUDA.jl: Unexpected \`mapreduce\` error: threads per block exceed GPU limit (640 \> 512](https://discourse.julialang.org/t/cuda-jl-unexpected-mapreduce-error-threads-per-block-exceed-gpu-limit-640-512/131778)

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**Author:** [@ykkan](https://discourse.julialang.org/u/ykkan)\
**Replies:** 9\
**Last updated:** [September 18, 2025, 11:27am UTC](https://discourse.julialang.org/t/cuda-jl-unexpected-mapreduce-error-threads-per-block-exceed-gpu-limit-640-512/131778 "2025-09-18T11:27:07Z")

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Hello everyone, I am using mapreduce from CUDA.jl to compute the sum of function evaluations over an array of SVector{7,T} data. The code looks roughly like this: function func(x1, x2, x3, x4, x5, x6, x7, x8, x9) …

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## [Slow model construction and solving with parameters](https://discourse.julialang.org/t/slow-model-construction-and-solving-with-parameters/132470)

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**Author:** [@chensunn](https://discourse.julialang.org/u/chensunn)\
**Replies:** 1\
**Last updated:** [September 17, 2025, 9:54pm UTC](https://discourse.julialang.org/t/slow-model-construction-and-solving-with-parameters/132470 "2025-09-17T21:54:05Z")

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I am trying to solve a problem where I wish to parameterize certain constants in my model for use in DiffOpt.jl. I use the constants to recursively generate a signal that I use elsewhere in the model. Formulating this pr…

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## [Make Lux.jl/Zygote.jl choose gradient type based on the superset of the weight type](https://discourse.julialang.org/t/make-lux-jl-zygote-jl-choose-gradient-type-based-on-the-superset-of-the-weight-type/132453)

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**Author:** [@IBArbitrary](https://discourse.julialang.org/u/IBArbitrary)\
**Replies:** 0\
**Last updated:** [September 17, 2025, 5:46am UTC](https://discourse.julialang.org/t/make-lux-jl-zygote-jl-choose-gradient-type-based-on-the-superset-of-the-weight-type/132453 "2025-09-17T05:46:01Z")

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I am using Lux.jl to implement models whose weights are complex, and the output can be real or complex. If i keep the output real and the weights complex, I cannot compute gradients because the gradient container is dete…

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## [\`apply\` do not work anymore with StatefulLuxLayer (by Luxv1.19)](https://discourse.julialang.org/t/apply-do-not-work-anymore-with-statefulluxlayer-by-luxv1-19/132317)

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**Author:** [@dmetivie](https://discourse.julialang.org/u/dmetivie)\
**Replies:** 5\
**Last updated:** [September 16, 2025, 1:52pm UTC](https://discourse.julialang.org/t/apply-do-not-work-anymore-with-statefulluxlayer-by-luxv1-19/132317 "2025-09-16T13:52:15Z")

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using Lux, Random nn = Lux.Dense(10, 10, tanh) ps, st = Lux.setup(Xoshiro(2024), nn) nn\_st = Lux.StatefulLuxLayer{true}(nn, nothing, st, nothing) input\_data = rand(10) Lux.apply(nn\_st, input\_data, ps) # do not w…

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## [Integrating large systems of ODEs](https://discourse.julialang.org/t/integrating-large-systems-of-odes/132428)

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**Author:** [@PersiaJK](https://discourse.julialang.org/u/PersiaJK)\
**Replies:** 1\
**Last updated:** [September 16, 2025, 8:08am UTC](https://discourse.julialang.org/t/integrating-large-systems-of-odes/132428 "2025-09-16T08:08:25Z")

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Hello! I am pretty new to Julia and I am looking for some answers and suggestions for a project of mine. I am translating a code from C to Julia because I would like to divide the code in modules and possibly take advan…

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## [How to debug ODE model aborting midway on sensitivity computation](https://discourse.julialang.org/t/how-to-debug-ode-model-aborting-midway-on-sensitivity-computation/132096)

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**Author:** [@Neodym](https://discourse.julialang.org/u/Neodym)\
**Replies:** 9\
**Last updated:** [September 15, 2025, 9:25pm UTC](https://discourse.julialang.org/t/how-to-debug-ode-model-aborting-midway-on-sensitivity-computation/132096 "2025-09-15T21:25:06Z")

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Hi there, I have an ODE model that results from the spatial discretization of a PDE including reaction terms. The rate coefficient of the reaction is calculated from an interpolation that is provided externally. I can …

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## [MTK not simplifying simple system](https://discourse.julialang.org/t/mtk-not-simplifying-simple-system/132327)

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**Author:** [@rob-five-0-seven](https://discourse.julialang.org/u/rob-five-0-seven)\
**Replies:** 1\
**Last updated:** [September 15, 2025, 11:29am UTC](https://discourse.julialang.org/t/mtk-not-simplifying-simple-system/132327 "2025-09-15T11:29:57Z")

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I want to use MTK to model some steady, compressible flow problems. Essentially solving problems at the boundaries of different components. The problems are all nonlinear for now; however, I’m testing the waters by playi…

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## [ODBC.jl to connect to an Oracle database on Linux](https://discourse.julialang.org/t/odbc-jl-to-connect-to-an-oracle-database-on-linux/97037)

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**Author:** [@klwlevy](https://discourse.julialang.org/u/klwlevy)\
**Replies:** 5\
**Last updated:** [September 15, 2025, 5:39am UTC](https://discourse.julialang.org/t/odbc-jl-to-connect-to-an-oracle-database-on-linux/97037 "2025-09-15T05:39:08Z")

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Hi there, I am succesfully using ODBC.jl to connect to an Oracle database on my local Windows laptop (with system-provided DSN from Windows ODBC). Now I am struggling to connect to the same database from a server runnin…

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## [MethodOfLines: How can I compute the Jacobian of the system of ODEs?](https://discourse.julialang.org/t/methodoflines-how-can-i-compute-the-jacobian-of-the-system-of-odes/132127)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 7\
**Last updated:** [September 12, 2025, 12:28pm UTC](https://discourse.julialang.org/t/methodoflines-how-can-i-compute-the-jacobian-of-the-system-of-odes/132127 "2025-09-12T12:28:29Z")

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How can I compute the Jacobian of the system of ODEs obtained by spatially discretising a linear advection equation? A MWE follows: using OrdinaryDiffEq, ModelingToolkit, MethodOfLines, DomainSets @independent\_variable…

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## [Makie.jl: How to choose a slice of a colormap in ColorBar](https://discourse.julialang.org/t/makie-jl-how-to-choose-a-slice-of-a-colormap-in-colorbar/132279)

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**Author:** [@JaydevSR](https://discourse.julialang.org/u/JaydevSR)\
**Replies:** 1\
**Last updated:** [September 12, 2025, 9:53am UTC](https://discourse.julialang.org/t/makie-jl-how-to-choose-a-slice-of-a-colormap-in-colorbar/132279 "2025-09-12T09:53:49Z")

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I am trying to plot a colorbar for my plot where I have used a particular slice of a colormap for different lines. But I can’t figure out how to restrict the colorbar to only display that section of the colormap and not …

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## [I want to build a hydrogeology model program](https://discourse.julialang.org/t/i-want-to-build-a-hydrogeology-model-program/132129)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 14\
**Last updated:** [September 12, 2025, 9:51am UTC](https://discourse.julialang.org/t/i-want-to-build-a-hydrogeology-model-program/132129 "2025-09-12T09:51:08Z")

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Hi everyone. I’m not really sure how to preface this. so I guess I’ll just provide my background, and my reason for wanting to try and build something useful in Julia for my usage. I recently finished my master’s degre…

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## [Gurobi reports UNKNOWN\_RESULT\_STATUS when Solution count = 10](https://discourse.julialang.org/t/gurobi-reports-unknown-result-status-when-solution-count-10/132311)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 3\
**Last updated:** [September 12, 2025, 6:26am UTC](https://discourse.julialang.org/t/gurobi-reports-unknown-result-status-when-solution-count-10/132311 "2025-09-12T06:26:38Z")

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I cannot figure out why the JuMP.primal\_status(model) is UNKNOWN\_RESULT\_STATUS here julia\> model # a model that is solved before and modified A JuMP Model ├ solver: Gurobi ├ objective\_sense: MIN\_SENSE │ └ objective\_func…

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## [Error using delay\_fnn](https://discourse.julialang.org/t/error-using-delay-fnn/132297)

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**Author:** [@dylanmcn](https://discourse.julialang.org/u/dylanmcn)\
**Replies:** 3\
**Last updated:** [September 11, 2025, 9:41pm UTC](https://discourse.julialang.org/t/error-using-delay-fnn/132297 "2025-09-11T21:41:28Z")

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Hello, I am trying to use the delay\_fnn function in the DynamicalSystems package and I keep getting the following error: ERROR: MethodError: no method matching StateSpaceSet{2, Float64, SVector{2, Float64}, Nothing}(::…

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## [Accessing df\_agent in agents.jl](https://discourse.julialang.org/t/accessing-df-agent-in-agents-jl/132285)

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**Author:** [@geoffD](https://discourse.julialang.org/u/geoffD)\
**Replies:** 0\
**Last updated:** [September 11, 2025, 1:59pm UTC](https://discourse.julialang.org/t/accessing-df-agent-in-agents-jl/132285 "2025-09-11T13:59:50Z")

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Hi, all. I am noticing that upon running simulations with Agents.jl, the agent dataframe (adf) and presumably the underlying agent data stored in df\_agent contain one record per agent per timestep. For one of my models,…

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## [Automatic differentiation of complex functions: simple workaround](https://discourse.julialang.org/t/automatic-differentiation-of-complex-functions-simple-workaround/75775)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 7\
**Last updated:** [September 11, 2025, 9:53am UTC](https://discourse.julialang.org/t/automatic-differentiation-of-complex-functions-simple-workaround/75775 "2025-09-11T09:53:48Z")

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I would like to share a simple technique to perform automatic differentiation (AD) of complex functions. I developed this technique a few months ago and have been using it successfully for past few months. The techniqu…

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## [Transform ODE Solution](https://discourse.julialang.org/t/transform-ode-solution/132262)

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**Author:** [@homocarbonis](https://discourse.julialang.org/u/homocarbonis)\
**Replies:** 5\
**Last updated:** [September 11, 2025, 8:37am UTC](https://discourse.julialang.org/t/transform-ode-solution/132262 "2025-09-11T08:37:16Z")

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Hi, I’m trying to solve some PDEs using a pseudo-spectral method with SplitODEProblem, which gives me a solution in the wavenumber domain. Is there a good way to take the inverse DCT of the solution, or am I going about…

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## [GLMakie: Reactive legends no longer work with ComputeGraph](https://discourse.julialang.org/t/glmakie-reactive-legends-no-longer-work-with-computegraph/132272)

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**Author:** [@matthew3245](https://discourse.julialang.org/u/matthew3245)\
**Replies:** 2\
**Last updated:** [September 11, 2025, 6:51am UTC](https://discourse.julialang.org/t/glmakie-reactive-legends-no-longer-work-with-computegraph/132272 "2025-09-11T06:51:40Z")

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I’m trying to have a textbox that the user can type in that adds a prefix to the start of legend entries. Here is a minimum working example: using GLMakie fig = Figure() ax = Axis(fig\[1:2, 1\]) textbox = Textbox(fig\[3, …

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## [NamedTuple from the ComponentArray](https://discourse.julialang.org/t/namedtuple-from-the-componentarray/132000)

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**Author:** [@IBArbitrary](https://discourse.julialang.org/u/IBArbitrary)\
**Replies:** 3\
**Last updated:** [September 11, 2025, 6:36am UTC](https://discourse.julialang.org/t/namedtuple-from-the-componentarray/132000 "2025-09-11T06:36:28Z")

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I am using Lux.jl and I want to access the flattened parameter vector. I use ComponentArrays.jl to achieve this. Now, if I have a flattened model vector m0, how do I get the ps back from this? # flattened vector from th…

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## [Cannot have newest Makie and ClassicalOrthogonalPolynomials at same time](https://discourse.julialang.org/t/cannot-have-newest-makie-and-classicalorthogonalpolynomials-at-same-time/131913)

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**Author:** [@AliceandBob](https://discourse.julialang.org/u/AliceandBob)\
**Replies:** 3\
**Last updated:** [September 11, 2025, 6:04am UTC](https://discourse.julialang.org/t/cannot-have-newest-makie-and-classicalorthogonalpolynomials-at-same-time/131913 "2025-09-11T06:04:50Z")

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Not sure where the conflict is. Is there a way to avoid this?

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## [Real-time graphics rendering (generative art)](https://discourse.julialang.org/t/real-time-graphics-rendering-generative-art/129160)

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**Author:** [@skolari93](https://discourse.julialang.org/u/skolari93)\
**Replies:** 19\
**Last updated:** [September 9, 2025, 6:39pm UTC](https://discourse.julialang.org/t/real-time-graphics-rendering-generative-art/129160 "2025-09-09T18:39:23Z")

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I am looking for a package or a toolchain which allows me to render generative visuals as fast as possible (as for example with processing, p5 or other creative languages). The reason I would like to use julia is, that …

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## [Autodifferentiation with FFT, with Enzyme?](https://discourse.julialang.org/t/autodifferentiation-with-fft-with-enzyme/128674)

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**Author:** [@jtravs](https://discourse.julialang.org/u/jtravs)\
**Replies:** 13\
**Last updated:** [September 9, 2025, 3:25pm UTC](https://discourse.julialang.org/t/autodifferentiation-with-fft-with-enzyme/128674 "2025-09-09T15:25:34Z")

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Hi, I’m trying to use autodifferentiation (for gradients, jacobians), working with a complex code that uses a lot of array mutation, custom structs, and FFTs (using FFTW). I got a small part of my code working by making…

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## [Compute Deviance Information Criterion for a Bayesian Model](https://discourse.julialang.org/t/compute-deviance-information-criterion-for-a-bayesian-model/132195)

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**Author:** [@dhruva-ahuja](https://discourse.julialang.org/u/dhruva-ahuja)\
**Replies:** 1\
**Last updated:** [September 9, 2025, 9:05am UTC](https://discourse.julialang.org/t/compute-deviance-information-criterion-for-a-bayesian-model/132195 "2025-09-09T09:05:46Z")

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Hello, I am struggling to compute Deviance Information Criterion (DIC) in Julia as Turing/MCMCDiagnosticTools do not have an implementation of DIC as in R dic.samples(mod2, n.iter=1e3). Backdrop: I am enrolled in a cou…

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## [Why is luxor generating 0-byte files?](https://discourse.julialang.org/t/why-is-luxor-generating-0-byte-files/132198)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 3\
**Last updated:** [September 8, 2025, 8:29pm UTC](https://discourse.julialang.org/t/why-is-luxor-generating-0-byte-files/132198 "2025-09-08T20:29:06Z")

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using Luxor @svg juliacircles(150) 400 400 "test1" @png juliacircles(150) 400 400 "test2" readdir() # file size name 09/08/2025 03:40 PM 0 test1.svg 09/08/2025 03:41 PM …

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## [Bifurcation Analysis of large nonlinear system](https://discourse.julialang.org/t/bifurcation-analysis-of-large-nonlinear-system/132184)

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**Author:** [@AlirezaMiraliakbar](https://discourse.julialang.org/u/AlirezaMiraliakbar)\
**Replies:** 4\
**Last updated:** [September 8, 2025, 4:35pm UTC](https://discourse.julialang.org/t/bifurcation-analysis-of-large-nonlinear-system/132184 "2025-09-08T16:35:52Z")

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Hi, I am new to Julia and BifurcationKit. I am trying to perform a bifurcation analysis for a kinetic model I am using to model a chemical plant. The plant’s nonlinear algebraic system of equation is quite large with 67 …

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