# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=165

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**Page:** 166

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## [How to solve volterra integral equation of second kind?](https://discourse.julialang.org/t/how-to-solve-volterra-integral-equation-of-second-kind/94332)

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**Author:** [@Jian\_ZUO](https://discourse.julialang.org/u/Jian_ZUO)\
**Replies:** 21\
**Last updated:** [September 19, 2023, 8:39am UTC](https://discourse.julialang.org/t/how-to-solve-volterra-integral-equation-of-second-kind/94332 "2023-09-19T08:39:00Z")

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Hi everyone, I need to solve a Volterra integral equation as follows: Here f(y) and K(x, y) are known functions (nonlinear) As an example, take f(y) = 3x^3; K(x, y) = 1 - exp(x). I saw this post about solving Volt…

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## [Webcam webapp](https://discourse.julialang.org/t/webcam-webapp/103604)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 4\
**Last updated:** [September 18, 2023, 8:42pm UTC](https://discourse.julialang.org/t/webcam-webapp/103604 "2023-09-18T20:42:39Z")

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I want to have a webpage function as a viewer for the webcam. In Genie, this is how I can do it without writing anything to disk and very low delay: using JpegTurbo, Observables, VideoIO using GenieFramework @genieto…

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## [Problem generating NoiseProcess following example in docs](https://discourse.julialang.org/t/problem-generating-noiseprocess-following-example-in-docs/103972)

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**Author:** [@KalelR](https://discourse.julialang.org/u/KalelR)\
**Replies:** 3\
**Last updated:** [September 18, 2023, 3:11pm UTC](https://discourse.julialang.org/t/problem-generating-noiseprocess-following-example-in-docs/103972 "2023-09-18T15:11:27Z")

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Hey! I’ve been trying to follow the example in DiffEqNoiseProcess.jl on how to create a NoiseProcess generating gaussian white noise. The code is basically using DiffEqNoiseProcess @inline function WHITE\_NOISE\_DIST(W…

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## [Definition of an integral function whose argument is the upper limit of integration](https://discourse.julialang.org/t/definition-of-an-integral-function-whose-argument-is-the-upper-limit-of-integration/103946)

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**Author:** [@aburousan](https://discourse.julialang.org/u/aburousan)\
**Replies:** 2\
**Last updated:** [September 18, 2023, 2:01pm UTC](https://discourse.julialang.org/t/definition-of-an-integral-function-whose-argument-is-the-upper-limit-of-integration/103946 "2023-09-18T14:01:55Z")

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Hi, I want to define a function let’s say, $$ f(x) = \\int\_0^x u^2 du /(e^{u^2+16} +1)^{\\frac{3/2}}$$ How can I do this?, A naive approach is to use a loop and just each time calculate the whole thing. But is there any…

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## [Gadfly is the best plotting library I've ever used](https://discourse.julialang.org/t/gadfly-is-the-best-plotting-library-ive-ever-used/57887)

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**Author:** [@tbenst](https://discourse.julialang.org/u/tbenst)\
**Replies:** 15\
**Last updated:** [September 18, 2023, 1:56pm UTC](https://discourse.julialang.org/t/gadfly-is-the-best-plotting-library-ive-ever-used/57887 "2023-09-18T13:56:32Z")

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I’ve used ggplot2, matplotlib, bokeh, seaborn, holoviews, VegaLite, plotly, Plots.jl, among many others, and Gadfly is the most productive & principled plotting library I’ve used yet. If you haven’t already given it a go…

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## [Makie don't use full color range in volume plots. (What am I doing wrong ?)](https://discourse.julialang.org/t/makie-dont-use-full-color-range-in-volume-plots-what-am-i-doing-wrong/103785)

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**Author:** [@Knud\_Sorensen](https://discourse.julialang.org/u/Knud_Sorensen)\
**Replies:** 7\
**Last updated:** [September 18, 2023, 12:50pm UTC](https://discourse.julialang.org/t/makie-dont-use-full-color-range-in-volume-plots-what-am-i-doing-wrong/103785 "2023-09-18T12:50:23Z")

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Hi. I plot at 3D array using: f=volume(vol; colormap=:redsblues, colorrange=(-2.0,2.0), lowclip=:red, highclip=:blue) But the plot doesn’t contain red. What is worng ?

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## [MTK & efficient formulation](https://discourse.julialang.org/t/mtk-efficient-formulation/103971)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 1\
**Last updated:** [September 18, 2023, 12:41pm UTC](https://discourse.julialang.org/t/mtk-efficient-formulation/103971 "2023-09-18T12:41:41Z")

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I have a file with a number of models (ModelingToolkit-MTK, functions, etc.) where, say, temperature, is a parameter. I want to explore what happens for different parameter values (e.g., temperature). To make sure that I…

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## [Support for Intel Mac AMD GPUs](https://discourse.julialang.org/t/support-for-intel-mac-amd-gpus/103933)

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**Author:** [@keynescoefen](https://discourse.julialang.org/u/keynescoefen)\
**Replies:** 4\
**Last updated:** [September 18, 2023, 12:09pm UTC](https://discourse.julialang.org/t/support-for-intel-mac-amd-gpus/103933 "2023-09-18T12:09:00Z")

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Hi, I saw this topic here and wondered whether there were any updates: ? It says that only AMD architectures on Linux are supported. Is there any hope of changing that in the future or is it a lost cause? The thing i…

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## [Setting X Axis Using Plots](https://discourse.julialang.org/t/setting-x-axis-using-plots/103957)

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**Author:** [@eweiss](https://discourse.julialang.org/u/eweiss)\
**Replies:** 1\
**Last updated:** [September 18, 2023, 8:13am UTC](https://discourse.julialang.org/t/setting-x-axis-using-plots/103957 "2023-09-18T08:13:27Z")

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I’m trying to plot stock prices which are daily but not on weekends. When I run this code using Dates, DataFrames, Plots df = DataFrame(Date=today()+Month(-1):Day(1):today(), rtn = rand(Float64, 32)) ticks = round.(df.D…

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## [Simulink-like block diagram editor for Julia?](https://discourse.julialang.org/t/simulink-like-block-diagram-editor-for-julia/78391)

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**Author:** [@pitsianis](https://discourse.julialang.org/u/pitsianis)\
**Replies:** 8\
**Last updated:** [September 17, 2023, 7:25pm UTC](https://discourse.julialang.org/t/simulink-like-block-diagram-editor-for-julia/78391 "2023-09-17T19:25:06Z")

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Is there any effort to build a block diagram editor for Julia to use with systems like ModelingToolkit.jl and Causal.jl?

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## [Finding the minimizer region of a function](https://discourse.julialang.org/t/finding-the-minimizer-region-of-a-function/103819)

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**Author:** [@yosuga](https://discourse.julialang.org/u/yosuga)\
**Replies:** 14\
**Last updated:** [September 17, 2023, 6:45pm UTC](https://discourse.julialang.org/t/finding-the-minimizer-region-of-a-function/103819 "2023-09-17T18:45:26Z")

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As an example, let f be a polynomial, f(z,w) = z + z^-1 + w - w^-1 + 2zw - 5, where z = exp(x\[1\]+iθ\[1\]), w = exp(x\[2\]+iθ\[2\]), x,θ ∈ R^2 Then we can define the Ronkin function as follows. function R(x) function …

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## [Makie: Removing gridlayouts](https://discourse.julialang.org/t/makie-removing-gridlayouts/103935)

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**Author:** [@f.ij](https://discourse.julialang.org/u/f.ij)\
**Replies:** 7\
**Last updated:** [September 17, 2023, 3:52pm UTC](https://discourse.julialang.org/t/makie-removing-gridlayouts/103935 "2023-09-17T15:52:37Z")

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I’m wondering if I can remove a GridLayout from a figure. Elements can be easily removed with delete! but this does not work on an entire GridLayout. If I want the layout of a figure programatically by deleting items tha…

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## [ChainRules for functions that "destroy their input arguments](https://discourse.julialang.org/t/chainrules-for-functions-that-destroy-their-input-arguments/103857)

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**Author:** [@lkdvos](https://discourse.julialang.org/u/lkdvos)\
**Replies:** 1\
**Last updated:** [September 16, 2023, 10:31pm UTC](https://discourse.julialang.org/t/chainrules-for-functions-that-destroy-their-input-arguments/103857 "2023-09-16T22:31:38Z")

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Some functions have the behaviour of using their inputs as workspace, and by doing so their documented behaviour is that they destroy the input. As an example, things like svd! work in such fashion. While in general, mu…

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## [Print all ellements of a variable-vector in once (broadcasting)](https://discourse.julialang.org/t/print-all-ellements-of-a-variable-vector-in-once-broadcasting/103884)

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**Author:** [@Fabian1](https://discourse.julialang.org/u/Fabian1)\
**Replies:** 5\
**Last updated:** [September 15, 2023, 10:58pm UTC](https://discourse.julialang.org/t/print-all-ellements-of-a-variable-vector-in-once-broadcasting/103884 "2023-09-15T22:58:05Z")

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Hi, I’ve just started with Julia, and I would like to print each element of a vector in one time for a variable (see line 37) in my optimization model under JuMP. It is already working for a defined parameter (D, see li…

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## [How to solve 2D PDE for heat conduction with x and y having different length (A rectangle)](https://discourse.julialang.org/t/how-to-solve-2d-pde-for-heat-conduction-with-x-and-y-having-different-length-a-rectangle/103907)

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**Author:** [@ShadmanSakief](https://discourse.julialang.org/u/ShadmanSakief)\
**Replies:** 1\
**Last updated:** [September 15, 2023, 5:17pm UTC](https://discourse.julialang.org/t/how-to-solve-2d-pde-for-heat-conduction-with-x-and-y-having-different-length-a-rectangle/103907 "2023-09-15T17:17:05Z")

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using NeuralPDE, Lux, Optimization, OptimizationOptimJL import ModelingToolkit: Interval @parameters x y @variables u(..) Dxx = Differential(x)^2 Dyy = Differential(y)^2 Dx = Differential(x) Dy = Differential(y) 2…

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## [Getting the upper bound of an objective function (MILP with HiGHS)](https://discourse.julialang.org/t/getting-the-upper-bound-of-an-objective-function-milp-with-highs/103890)

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**Author:** [@cf357](https://discourse.julialang.org/u/cf357)\
**Replies:** 4\
**Last updated:** [September 15, 2023, 5:02pm UTC](https://discourse.julialang.org/t/getting-the-upper-bound-of-an-objective-function-milp-with-highs/103890 "2023-09-15T17:02:47Z")

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I’m working on an assignment problem where the solver maximizes @objective(model, Max, sum(B\[u\] for u in U)) where B is a binary vector of entities satisfying some conditions in the assignment plan A\[u, f, t\], which de…

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## [Error with remake function in ODE Problems](https://discourse.julialang.org/t/error-with-remake-function-in-ode-problems/103902)

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**Author:** [@Nick1](https://discourse.julialang.org/u/Nick1)\
**Replies:** 0\
**Last updated:** [September 15, 2023, 3:19pm UTC](https://discourse.julialang.org/t/error-with-remake-function-in-ode-problems/103902 "2023-09-15T15:19:20Z")

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Hi everyone, I am importing an SBML file and try to change the initial condition and remake the problem but I get the following error: ERROR: ArgumentError: This problem does not support symbolic maps with remake, i.e.…

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## [ODE problem error](https://discourse.julialang.org/t/ode-problem-error/103876)

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**Author:** [@River\_He](https://discourse.julialang.org/u/River_He)\
**Replies:** 2\
**Last updated:** [September 15, 2023, 2:41pm UTC](https://discourse.julialang.org/t/ode-problem-error/103876 "2023-09-15T14:41:01Z")

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Hello everyone, I’m currently working on solving an ODE problem using Julia, but I’ve run into some issues. Before diving into possible modifications to my model, I’d like to first rule out any potential problems arisin…

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## [PDE discretization error in MethodOfLines.jl](https://discourse.julialang.org/t/pde-discretization-error-in-methodoflines-jl/78566)

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**Author:** [@RickDW](https://discourse.julialang.org/u/RickDW)\
**Replies:** 23\
**Last updated:** [September 15, 2023, 11:27am UTC](https://discourse.julialang.org/t/pde-discretization-error-in-methodoflines-jl/78566 "2023-09-15T11:27:58Z")

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Hi all, I’m currently working on implementing a relatively simple reaction-diffusion-convection model of a 2D hydrogen flame. The PDESystem is created successfully, but the discretization step using methodoflines.jl fail…

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## [Solve bilevel optimization the stupid way](https://discourse.julialang.org/t/solve-bilevel-optimization-the-stupid-way/103024)

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**Author:** [@cricci](https://discourse.julialang.org/u/cricci)\
**Replies:** 6\
**Last updated:** [September 15, 2023, 9:27am UTC](https://discourse.julialang.org/t/solve-bilevel-optimization-the-stupid-way/103024 "2023-09-15T09:27:38Z")

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I would like to solve a bilevel optimization problem in a dumb way. Consider the following (as an example) \\min\_{x,y}\\quad x^4 - \\sin(y)\\\\ \\text{s.t.}\\quad x \\geq 2, x^3+y^3 \\leq 1\\\\ y(x) \\in \\arg\\min\_{y} y^2 + x\\\\ 3…

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## [ANN: JuMP v1.15 is released](https://discourse.julialang.org/t/ann-jump-v1-15-is-released/103875)

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**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 0\
**Last updated:** [September 15, 2023, 3:10am UTC](https://discourse.julialang.org/t/ann-jump-v1-15-is-released/103875 "2023-09-15T03:10:53Z")

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Dear all, I am very pleased to announce the release of JuMP v1.15. This is a very large minor release because it introduces an entirely new API for nonlinear programs. To summarize, there is now a first-class nonlinea…

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## [Get presolved model from Gurobi](https://discourse.julialang.org/t/get-presolved-model-from-gurobi/103827)

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**Author:** [@Ken\_Lin](https://discourse.julialang.org/u/Ken_Lin)\
**Replies:** 5\
**Last updated:** [September 15, 2023, 1:11am UTC](https://discourse.julialang.org/t/get-presolved-model-from-gurobi/103827 "2023-09-15T01:11:14Z")

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Hi, in Julia is it possible to get the model after Gurobi finishes “presolve”? That is the model after being simplified by Gurobi (less variables, constraints,…). The method Model.presolve() in the Gurobi Python interfa…

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## [Julia Packages for meta-analysis?](https://discourse.julialang.org/t/julia-packages-for-meta-analysis/22451)

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**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 3\
**Last updated:** [September 14, 2023, 7:52pm UTC](https://discourse.julialang.org/t/julia-packages-for-meta-analysis/22451 "2023-09-14T19:52:31Z")

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Hello. What Julia package can I use to easily do meta-analysis? Till now I’ve been using some R packages such as metafor or metagen. http://www.metafor-project.org/doku.php

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## [Examples for port-Hamiltonian modelling and control of physical systems?](https://discourse.julialang.org/t/examples-for-port-hamiltonian-modelling-and-control-of-physical-systems/103787)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 3\
**Last updated:** [September 14, 2023, 5:52pm UTC](https://discourse.julialang.org/t/examples-for-port-hamiltonian-modelling-and-control-of-physical-systems/103787 "2023-09-14T17:52:47Z")

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Are there any examples in Julia how to model and control port-Hamiltonian systems? See: https://www.math.rug.nl/arjan/DownloadLectures/Benelux08.pdf Can it be done with ModelingToolkit, or are there better ways?

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## [Optimization of parameters of a dynamic problem with ModelingToolkit](https://discourse.julialang.org/t/optimization-of-parameters-of-a-dynamic-problem-with-modelingtoolkit/103784)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 3\
**Last updated:** [September 14, 2023, 2:17pm UTC](https://discourse.julialang.org/t/optimization-of-parameters-of-a-dynamic-problem-with-modelingtoolkit/103784 "2023-09-14T14:17:42Z")

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Hello all ! I have a nonlinear ODE problem that I set up with ModelingToolkit (great job with this awesome package !), for which I can compute some steady-state (with SteadyStateProblem) or transient solutions (with ODE…

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## [@register\_symbolic with vector variables](https://discourse.julialang.org/t/register-symbolic-with-vector-variables/103419)

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**Author:** [@jondavis847](https://discourse.julialang.org/u/jondavis847)\
**Replies:** 10\
**Last updated:** [September 14, 2023, 4:00pm UTC](https://discourse.julialang.org/t/register-symbolic-with-vector-variables/103419 "2023-09-14T16:00:31Z")

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It seems that @register\_symbolic will successfully stop tracing on scalar variables, but continues to trace with vector variables. Anyway currently to get register\_symbolic to stop tracing on vector variables? julia\> f(…

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## [Adding and updating a scalar to the Integerator Cache in DifferentialEquations.jl](https://discourse.julialang.org/t/adding-and-updating-a-scalar-to-the-integerator-cache-in-differentialequations-jl/103805)

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**Author:** [@cdawg](https://discourse.julialang.org/u/cdawg)\
**Replies:** 12\
**Last updated:** [September 14, 2023, 3:28pm UTC](https://discourse.julialang.org/t/adding-and-updating-a-scalar-to-the-integerator-cache-in-differentialequations-jl/103805 "2023-09-14T15:28:02Z")

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Background. I have a nice stochastic jump-piecewise-ODE behaving as it should. Thanks @ChrisRackauckas and team! Basically this would have been completely impossible in any other language/package! Now I want to calculat…

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## [2D wave equation with open boundary conditions](https://discourse.julialang.org/t/2d-wave-equation-with-open-boundary-conditions/103290)

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**Author:** [@thoth291](https://discourse.julialang.org/u/thoth291)\
**Replies:** 32\
**Last updated:** [September 14, 2023, 1:57pm UTC](https://discourse.julialang.org/t/2d-wave-equation-with-open-boundary-conditions/103290 "2023-09-14T13:57:38Z")

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Here is the equation I’m trying to solve and I’m surely doing something wrong - but I don’t know what exactly. Could you please help me to understand where I’m thinking wrong about it? using NeuralPDE, Lux, LuxCUDA, Ra…

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## [Symbolic ODE/PDE in Vector form with Symbolics/ModelingToolkit](https://discourse.julialang.org/t/symbolic-ode-pde-in-vector-form-with-symbolics-modelingtoolkit/103793)

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**Author:** [@Bizzi](https://discourse.julialang.org/u/Bizzi)\
**Replies:** 6\
**Last updated:** [September 14, 2023, 1:52pm UTC](https://discourse.julialang.org/t/symbolic-ode-pde-in-vector-form-with-symbolics-modelingtoolkit/103793 "2023-09-14T13:52:06Z")

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I’ve been having a hard time trying to use vector-valued equations (as opposed to vectors of equations) in Symbolics/ModelingToolkit. I remember reading somewhere in either docs that his feature was somewhat experimental…

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## [Implementing Maple water hammer example (PDE's)](https://discourse.julialang.org/t/implementing-maple-water-hammer-example-pdes/103501)

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**Author:** [@victor](https://discourse.julialang.org/u/victor)\
**Replies:** 3\
**Last updated:** [September 14, 2023, 10:00am UTC](https://discourse.julialang.org/t/implementing-maple-water-hammer-example-pdes/103501 "2023-09-14T10:00:08Z")

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Hi I’m trying to recreate this Maple water hammer example in Julia. Link to Maple example below. I’m not able to get anything close to stable results. Some help here would be greatly appreciated. (I know I’ve made some …

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