# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=31

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**Page:** 32

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## [Lollipopt project (Probably not working so don't take it seriously.)](https://discourse.julialang.org/t/lollipopt-project-probably-not-working-so-dont-take-it-seriously/131199)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 4\
**Last updated:** [August 1, 2025, 11:51am UTC](https://discourse.julialang.org/t/lollipopt-project-probably-not-working-so-dont-take-it-seriously/131199 "2025-08-01T11:51:19Z")

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You have a mixed-integer linear programming problem. You’re tired of free solvers being like 100x slower than commercial solvers, right? I think I found the culprit. It’s hard to contribute to free solvers despite them…

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## [Sparse matrix multiplication for Metal](https://discourse.julialang.org/t/sparse-matrix-multiplication-for-metal/131088)

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**Author:** [@Marco\_Lombardi](https://discourse.julialang.org/u/Marco_Lombardi)\
**Replies:** 15\
**Last updated:** [July 31, 2025, 5:59pm UTC](https://discourse.julialang.org/t/sparse-matrix-multiplication-for-metal/131088 "2025-07-31T17:59:44Z")

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I need to perform a multiplication between two fairly large sparse matrices C = A \* B and I would like to try using the GPU for that. The problem arises in a context where A represents a fixed 2D convolution kernel, whil…

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## [Solving for transcendental equation](https://discourse.julialang.org/t/solving-for-transcendental-equation/131229)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 15\
**Last updated:** [July 31, 2025, 4:14pm UTC](https://discourse.julialang.org/t/solving-for-transcendental-equation/131229 "2025-07-31T16:14:16Z")

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Hi, I have the function f\_n(x) = e^x T\_n(x), where T\_n are Touchard’s polynomials. The function is bijective from R to R and everything is Ok, just that the inverse is unknown… It has the nice taylor exapnsion : f\_n(x)…

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## [Maxwell-Boltzmann Distribution using Distributions.jl](https://discourse.julialang.org/t/maxwell-boltzmann-distribution-using-distributions-jl/131210)

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**Author:** [@prconlin](https://discourse.julialang.org/u/prconlin)\
**Replies:** 1\
**Last updated:** [July 30, 2025, 5:13pm UTC](https://discourse.julialang.org/t/maxwell-boltzmann-distribution-using-distributions-jl/131210 "2025-07-30T17:13:01Z")

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Hello, Distributions.jl does not have an implementation of the Maxwell-Boltzmann distribution, but it does have the Chi distribution, which is a more general form of the Maxwell-Boltzmann case. I’m hoping to simply app…

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## [How to get all the registered variable names of a \`JuMP\` model?](https://discourse.julialang.org/t/how-to-get-all-the-registered-variable-names-of-a-jump-model/113837)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 3\
**Last updated:** [July 30, 2025, 2:39am UTC](https://discourse.julialang.org/t/how-to-get-all-the-registered-variable-names-of-a-jump-model/113837 "2025-07-30T02:39:45Z")

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Is there any method to obtaining all the registered variable names (symbols) of a JuMP model? And, if the variables have been set String names, how to get their original symbolic names?

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## [Using Enzyme.jl with Flux: Issues Computing Gradients of a Model with Duplicated Parameters and Mixed Forward/Reverse AD](https://discourse.julialang.org/t/using-enzyme-jl-with-flux-issues-computing-gradients-of-a-model-with-duplicated-parameters-and-mixed-forward-reverse-ad/131135)

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**Author:** [@Gianmarco](https://discourse.julialang.org/u/Gianmarco)\
**Replies:** 11\
**Last updated:** [July 29, 2025, 11:23pm UTC](https://discourse.julialang.org/t/using-enzyme-jl-with-flux-issues-computing-gradients-of-a-model-with-duplicated-parameters-and-mixed-forward-reverse-ad/131135 "2025-07-29T23:23:35Z")

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Hi everyone, I’m trying to use Enzyme.jl to compute gradients for a Flux model during training. My goal is to differentiate a custom loss function that combines a regular mean squared error term with an additional gradi…

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## [Just-in-time gradient optimization idea](https://discourse.julialang.org/t/just-in-time-gradient-optimization-idea/131170)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 2\
**Last updated:** [July 29, 2025, 10:17pm UTC](https://discourse.julialang.org/t/just-in-time-gradient-optimization-idea/131170 "2025-07-29T22:17:28Z")

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Disclaimer: The idea might look simple in theory, but it might be very hard to implement. Imagine you had a machine learning model comprising multiple batches of parameters. Normally, you differentiate through the entir…

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## [Plotting in GeoStats](https://discourse.julialang.org/t/plotting-in-geostats/130770)

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**Author:** [@beppi](https://discourse.julialang.org/u/beppi)\
**Replies:** 27\
**Last updated:** [July 29, 2025, 8:39pm UTC](https://discourse.julialang.org/t/plotting-in-geostats/130770 "2025-07-29T20:39:52Z")

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Hey, I’ve seen the page here: Visualization · GeoStats.jl However as a newbie I might be unable to understand how to do this. I have a GeoTable of points and I want to plot the points coloured by a column in the GeoTab…

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## [Accepted mask type for Augmentor.jl](https://discourse.julialang.org/t/accepted-mask-type-for-augmentor-jl/131142)

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**Author:** [@cirobr](https://discourse.julialang.org/u/cirobr)\
**Replies:** 0\
**Last updated:** [July 28, 2025, 5:56pm UTC](https://discourse.julialang.org/t/accepted-mask-type-for-augmentor-jl/131142 "2025-07-28T17:56:11Z")

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Cheers, I’m a new Augmentor.jl user. Need to apply same augmentation to images and masks for training a semantic segmentation model. Augmentation of images has worked out smoothly. Issue is when augmenting masks as the …

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## [Finding a region of attraction using sum of squares optimization](https://discourse.julialang.org/t/finding-a-region-of-attraction-using-sum-of-squares-optimization/131067)

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**Author:** [@lieskjur](https://discourse.julialang.org/u/lieskjur)\
**Replies:** 10\
**Last updated:** [July 28, 2025, 5:46pm UTC](https://discourse.julialang.org/t/finding-a-region-of-attraction-using-sum-of-squares-optimization/131067 "2025-07-28T17:46:18Z")

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Out of interest I decided to explore sum of squares optimization in the context of Lyapunov functions. Right now I’d like to use it to find the region of attraction for the value function (viewed as a Lyapunov function) …

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## [Memory problem when using SlurmClusterManager.jl to add workers](https://discourse.julialang.org/t/memory-problem-when-using-slurmclustermanager-jl-to-add-workers/131039)

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**Author:** [@CeterisPartybus](https://discourse.julialang.org/u/CeterisPartybus)\
**Replies:** 6\
**Last updated:** [July 28, 2025, 5:32pm UTC](https://discourse.julialang.org/t/memory-problem-when-using-slurmclustermanager-jl-to-add-workers/131039 "2025-07-28T17:32:11Z")

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I am new to using Distributed.jl on a cluster. I am trying to run jobs on a cluster with multiple nodes. Even though I specify a single node my Julia program should run on in the batch file, there seems to be a problem t…

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## [Introducing DCM.jl: a Julia package to estimate Discrete Choice Models](https://discourse.julialang.org/t/introducing-dcm-jl-a-julia-package-to-estimate-discrete-choice-models/131122)

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**Author:** [@ig\_hdez](https://discourse.julialang.org/u/ig_hdez)\
**Replies:** 3\
**Last updated:** [July 28, 2025, 4:13pm UTC](https://discourse.julialang.org/t/introducing-dcm-jl-a-julia-package-to-estimate-discrete-choice-models/131122 "2025-07-28T16:13:18Z")

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Hi everyone! I’m glad to share DCM.jl, a new Julia package for estimating Discrete Choice Models (Logit, Mixed Logit, Latent Class) with a focus on speed, modularity, and transparency. Some key features: Model utili…

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## [DifferentiationInterface do-block best practices](https://discourse.julialang.org/t/differentiationinterface-do-block-best-practices/131125)

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**Author:** [@afleming](https://discourse.julialang.org/u/afleming)\
**Replies:** 1\
**Last updated:** [July 28, 2025, 3:15pm UTC](https://discourse.julialang.org/t/differentiationinterface-do-block-best-practices/131125 "2025-07-28T15:15:18Z")

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Is it better / recommended to use do-blocks that capture variables or should I use the Context mechanism provided by DifferentiationInterface? Even though this pack = (y0 = 1.0, y1 = 2.0) x1 = \[2.0, 4.0\] jac = Differen…

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## [Calling complete() adds differential constraints to algebraic extension of ReactionSystem](https://discourse.julialang.org/t/calling-complete-adds-differential-constraints-to-algebraic-extension-of-reactionsystem/131115)

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**Author:** [@spackman](https://discourse.julialang.org/u/spackman)\
**Replies:** 2\
**Last updated:** [July 28, 2025, 2:07pm UTC](https://discourse.julialang.org/t/calling-complete-adds-differential-constraints-to-algebraic-extension-of-reactionsystem/131115 "2025-07-28T14:07:17Z")

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Hey guys, I’m doing some experimentation with Catalyst.jl and algebraic equations to define systems where the system volume is not constant. This can occur when the major solvent is a reactant in appreciable quantities…

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## [Mixed Logit Model in Julia](https://discourse.julialang.org/t/mixed-logit-model-in-julia/24995)

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**Author:** [@ig\_hdez](https://discourse.julialang.org/u/ig_hdez)\
**Replies:** 9\
**Last updated:** [July 28, 2025, 12:07pm UTC](https://discourse.julialang.org/t/mixed-logit-model-in-julia/24995 "2025-07-28T12:07:32Z")

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Hi everyone! I’ve created a script to estimate Mixed Logit Models based on the codes of Kenneth Train (Kenneth Train's Software) for MATLAB. The code and an example can be found here: https://github.com/ighdez/MultiLog…

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## [Skew Student T Distr? (Hansen or Fernandes Steel)](https://discourse.julialang.org/t/skew-student-t-distr-hansen-or-fernandes-steel/131041)

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**Author:** [@Alex1](https://discourse.julialang.org/u/Alex1)\
**Replies:** 6\
**Last updated:** [July 26, 2025, 7:32pm UTC](https://discourse.julialang.org/t/skew-student-t-distr-hansen-or-fernandes-steel/131041 "2025-07-26T19:32:13Z")

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Hi, is there a Skew Student T implementation in Julia? Hansen or Fernandes-Steel variants, with analytical pdf, cdf, quantile?

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## [Catalyst.jl - updating kinetic parameters to be time-dependent after loading a reaction network](https://discourse.julialang.org/t/catalyst-jl-updating-kinetic-parameters-to-be-time-dependent-after-loading-a-reaction-network/130989)

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**Author:** [@spackman](https://discourse.julialang.org/u/spackman)\
**Replies:** 12\
**Last updated:** [July 27, 2025, 8:23pm UTC](https://discourse.julialang.org/t/catalyst-jl-updating-kinetic-parameters-to-be-time-dependent-after-loading-a-reaction-network/130989 "2025-07-27T20:23:59Z")

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Hi there, I am trying to build a ReactionSystem with time-varying parameters using ReactionNetworkImporters.jl function loadrxnetwork(). I want to initialize the network with placeholder time-varying kinetic parameters …

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## [Add Stipple,jl reactive elements to existed Genie.jl app with controllers](https://discourse.julialang.org/t/add-stipple-jl-reactive-elements-to-existed-genie-jl-app-with-controllers/130726)

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**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 6\
**Last updated:** [July 27, 2025, 12:42pm UTC](https://discourse.julialang.org/t/add-stipple-jl-reactive-elements-to-existed-genie-jl-app-with-controllers/130726 "2025-07-27T12:42:14Z")

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So I made Genie.jl app as it described in movie example. With controllers, route.jl, ets… Is it possible to use Stipple.jl functionality in existed project? I have no app.jl in Genie.jl project… Where I should use al…

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## [Problem with Genie.jl newapp\_mvc](https://discourse.julialang.org/t/problem-with-genie-jl-newapp-mvc/130701)

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**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 2\
**Last updated:** [July 27, 2025, 2:04pm UTC](https://discourse.julialang.org/t/problem-with-genie-jl-newapp-mvc/130701 "2025-07-27T14:04:30Z")

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Try to make new App import Pkg path = "D:\\\\GenieTest" cd(path) Pkg.activate("") Pkg.add("Genie") using Genie Genie.Generator.newapp\_mvc("NewApp") And get: Activating new project at \`D:\\GenieTest\\NewApp\\test\` Acti…

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## [Some question on column generation, branch and price, Coluna](https://discourse.julialang.org/t/some-question-on-column-generation-branch-and-price-coluna/131084)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 2\
**Last updated:** [July 27, 2025, 3:55am UTC](https://discourse.julialang.org/t/some-question-on-column-generation-branch-and-price-coluna/131084 "2025-07-27T03:55:10Z")

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Since I’m studying this topic recently. I wonder if there is anyone who is interested and can hence discuss with me. Benders I don’t think this structure is going to be handled by Benders decomposition. For this str…

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## [Gurobi fails to properly report an ERROR, when NonConvex is 0](https://discourse.julialang.org/t/gurobi-fails-to-properly-report-an-error-when-nonconvex-is-0/130932)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 5\
**Last updated:** [July 27, 2025, 3:15am UTC](https://discourse.julialang.org/t/gurobi-fails-to-properly-report-an-error-when-nonconvex-is-0/130932 "2025-07-27T03:15:45Z")

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I discover this behavior of Gurobi, which I think is not exactly expected. According to Gurobi’s doc, if NonConvex is set to 0, then Gurobi should ERROR when a nonconvex quadratic constraint is present. julia\> import J…

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## [Smooth progress bar for multithreads sampling in turing.jl](https://discourse.julialang.org/t/smooth-progress-bar-for-multithreads-sampling-in-turing-jl/130768)

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**Author:** [@Sahil\_Khan](https://discourse.julialang.org/u/Sahil_Khan)\
**Replies:** 6\
**Last updated:** [July 26, 2025, 1:13pm UTC](https://discourse.julialang.org/t/smooth-progress-bar-for-multithreads-sampling-in-turing-jl/130768 "2025-07-26T13:13:42Z")

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Hello everyone, Im working with turing.jl and what I have noticed that when sampling multiple chains with mulithreads option. Progress bar show progress based on number of chains used for example if I use 3 chains then …

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## [Generalized Chi-squared distribution](https://discourse.julialang.org/t/generalized-chi-squared-distribution/106055)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 5\
**Last updated:** [July 26, 2025, 7:37am UTC](https://discourse.julialang.org/t/generalized-chi-squared-distribution/106055 "2025-07-26T07:37:25Z")

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Does anybody know some attempt to implement the Generalized Chi-squared distribution in Julia? (First I looked for it in Distributions.jl, but I have not found it there or anywhere else.)

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## [Support for adjoint sensitivities with \`SciMLStructures\` in ODE problems](https://discourse.julialang.org/t/support-for-adjoint-sensitivities-with-scimlstructures-in-ode-problems/131049)

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**Author:** [@albangossard](https://discourse.julialang.org/u/albangossard)\
**Replies:** 2\
**Last updated:** [July 25, 2025, 6:15pm UTC](https://discourse.julialang.org/t/support-for-adjoint-sensitivities-with-scimlstructures-in-ode-problems/131049 "2025-07-25T18:15:02Z")

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Hi all, In complex geoscientific models, it’s common to have many simulation parameters that need to be passed into the ODE function. At the same time, we often want to compute gradients with respect to some of these pa…

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## [Help speeding up \`DiscreteProblem\`](https://discourse.julialang.org/t/help-speeding-up-discreteproblem/130986)

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**Author:** [@sdwfrost](https://discourse.julialang.org/u/sdwfrost)\
**Replies:** 5\
**Last updated:** [July 25, 2025, 2:48pm UTC](https://discourse.julialang.org/t/help-speeding-up-discreteproblem/130986 "2025-07-25T14:48:49Z")

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Hi Everyone, I’m finding that using DiscreteProblem on my toy example is about 4x slower than a vanilla loop with pre-allocated output. DiscreteProblem version Base Julia version My model is as follows: function sir…

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## [Dealing with type stability when nothing can be returned](https://discourse.julialang.org/t/dealing-with-type-stability-when-nothing-can-be-returned/131040)

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**Author:** [@sea\_slug](https://discourse.julialang.org/u/sea_slug)\
**Replies:** 1\
**Last updated:** [July 25, 2025, 9:58am UTC](https://discourse.julialang.org/t/dealing-with-type-stability-when-nothing-can-be-returned/131040 "2025-07-25T09:58:53Z")

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I have a relatively complex Agent Based Model (ABM) that I am profiling. One function in particular (get\_shark\_pos) is dominating the runtime according to the flame graph. I am surprised because the function is very simp…

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## [Particle Filtering methods](https://discourse.julialang.org/t/particle-filtering-methods/130828)

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**Author:** [@Tanya123](https://discourse.julialang.org/u/Tanya123)\
**Replies:** 9\
**Last updated:** [July 25, 2025, 6:07am UTC](https://discourse.julialang.org/t/particle-filtering-methods/130828 "2025-07-25T06:07:43Z")

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Hi everyone! I’m new to data assimilation and working with particle filters. I have a model where the β function is sinusoidal and linearly advects over time. It’s a 2D field on an 80×80 grid with double bumps. I’m tryi…

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## [RMSE vague in 2D particle filtering with LowLevelParticleFilters.jl?](https://discourse.julialang.org/t/rmse-vague-in-2d-particle-filtering-with-lowlevelparticlefilters-jl/131042)

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**Author:** [@Tanya123](https://discourse.julialang.org/u/Tanya123)\
**Replies:** 1\
**Last updated:** [July 25, 2025, 6:37am UTC](https://discourse.julialang.org/t/rmse-vague-in-2d-particle-filtering-with-lowlevelparticlefilters-jl/131042 "2025-07-25T06:37:13Z")

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Hi all, I’m applying particle filtering to a 2D linear advection problem (60x60 grid, 3600 states) using LowLevelParticleFilters.jl with: \*Particles: 10,000 \*Process noise: 0.01 \*Measurement noise: 0.1 at 100 random …

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## [Solving a free-boundary PDE by mapping to a fixed domain](https://discourse.julialang.org/t/solving-a-free-boundary-pde-by-mapping-to-a-fixed-domain/131006)

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**Author:** [@naoufelcre](https://discourse.julialang.org/u/naoufelcre)\
**Replies:** 0\
**Last updated:** [July 24, 2025, 2:21pm UTC](https://discourse.julialang.org/t/solving-a-free-boundary-pde-by-mapping-to-a-fixed-domain/131006 "2025-07-24T14:21:34Z")

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Hello everyone, I’m trying to solve a 1-D Free Boundary PDE using Julia and it is my first time manipulating the language for such a complex problem so I apologize if this sounds trivial to most of you. Basically, the …

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## [Catalyst.jl - what is the appropriate way to model equilibrium (i.e. pKa?)](https://discourse.julialang.org/t/catalyst-jl-what-is-the-appropriate-way-to-model-equilibrium-i-e-pka/130149)

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**Author:** [@spackman](https://discourse.julialang.org/u/spackman)\
**Replies:** 8\
**Last updated:** [July 24, 2025, 11:28am UTC](https://discourse.julialang.org/t/catalyst-jl-what-is-the-appropriate-way-to-model-equilibrium-i-e-pka/130149 "2025-07-24T11:28:16Z")

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Hello again, I’m working to add some additional equilibrium conditions to a reaction network, particularly pKa. I’m inclined to think that algebraic constraint equations are the appropriate choice here assuming that th…

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