# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=50

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**Page:** 51

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## [ANN: seeking feedback on experimental support for vector-valued user-defined functions](https://discourse.julialang.org/t/ann-seeking-feedback-on-experimental-support-for-vector-valued-user-defined-functions/127523)

<div class="topic-metadata">

**Author:** [@odow](https://discourse.julialang.org/u/odow)\
**Replies:** 0\
**Last updated:** [March 30, 2025, 8:12pm UTC](https://discourse.julialang.org/t/ann-seeking-feedback-on-experimental-support-for-vector-valued-user-defined-functions/127523 "2025-03-30T20:12:10Z")

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Dear all, a fairly common feature request is for vector-valued user defined functions. Ipopt.jl v1.8.0 adds experimental support for Ipopt.\_VectorNonlinearOracle. Please see this issue for example usage and future plans…

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## [Can I query is\_continuous about a JuMP model?](https://discourse.julialang.org/t/can-i-query-is-continuous-about-a-jump-model/127484)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 6\
**Last updated:** [March 30, 2025, 7:16pm UTC](https://discourse.julialang.org/t/can-i-query-is-continuous-about-a-jump-model/127484 "2025-03-30T19:16:50Z")

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We can learn from the print(model) (🍅) that if a model has a variable which is not purely continuous (e.g. Integer/binary/semi~). julia\> model A JuMP Model ├ solver: Gurobi ├ objective\_sense: FEASIBILITY\_SENSE ├ num\_var…

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## [Julia image display on Mac goes dark](https://discourse.julialang.org/t/julia-image-display-on-mac-goes-dark/127436)

<div class="topic-metadata">

**Author:** [@rmfritz](https://discourse.julialang.org/u/rmfritz)\
**Replies:** 10\
**Last updated:** [March 30, 2025, 1:46am UTC](https://discourse.julialang.org/t/julia-image-display-on-mac-goes-dark/127436 "2025-03-30T01:46:59Z")

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I’m working with some images in Julia, and I’m running into a problem; the images, when displayed from the Julia command line with ImageView, or within a Jupyter notebook, are much much darker than when they are display…

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## [Solving First Order Differential Equations with Julia](https://discourse.julialang.org/t/solving-first-order-differential-equations-with-julia/127485)

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**Author:** [@ghoshr](https://discourse.julialang.org/u/ghoshr)\
**Replies:** 2\
**Last updated:** [March 29, 2025, 5:11pm UTC](https://discourse.julialang.org/t/solving-first-order-differential-equations-with-julia/127485 "2025-03-29T17:11:46Z")

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Solving First Order Differential Equations with Julia I wrote a full tutorial on solving first order ODEs in Julia using the DifferentialEquations.jl package. It provides a gentle introduction to Differential Equations i…

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## [Gurobi LP solver's cut-off behavior---an example](https://discourse.julialang.org/t/gurobi-lp-solvers-cut-off-behavior-an-example/127454)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 6\
**Last updated:** [March 28, 2025, 11:05pm UTC](https://discourse.julialang.org/t/gurobi-lp-solvers-cut-off-behavior-an-example/127454 "2025-03-28T23:05:03Z")

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I find an interesting example about Gurobi’s LP solver. There are 2 linear constraints in my LP, named fixed and cut. The outcomes for the following 2 schemes are different: Add Both constraints, and solve only once A…

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## [Blog post on the “IJKLM model” with AlgebraicJulia tools](https://discourse.julialang.org/t/blog-post-on-the-ijklm-model-with-algebraicjulia-tools/121562)

<div class="topic-metadata">

**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 1\
**Last updated:** [March 27, 2025, 2:52pm UTC](https://discourse.julialang.org/t/blog-post-on-the-ijklm-model-with-algebraicjulia-tools/121562 "2025-03-27T14:52:10Z")

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Hi all, I recently wrote a blog post at the AlgebraicJulia blog: JuMP-ing with AlgebraicJulia I: The IJKLM model – AlgebraicJulia blog, which explores how to use some of the tools in the AlgebraicJulia ecosystem to addr…

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## [Optimize loss calculation on gpu](https://discourse.julialang.org/t/optimize-loss-calculation-on-gpu/127458)

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**Author:** [@Fabrice\_Rosay](https://discourse.julialang.org/u/Fabrice_Rosay)\
**Replies:** 0\
**Last updated:** [March 28, 2025, 2:41pm UTC](https://discourse.julialang.org/t/optimize-loss-calculation-on-gpu/127458 "2025-03-28T14:41:24Z")

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Is there anything i can do to speed up this loss calculation ? (Trajectory Balanced loss for Flow Network from \[2310.02779\] Expected flow networks in stochastic environments and two-player zero-sum games) function gpu\_t…

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## [@brownian vector?](https://discourse.julialang.org/t/brownian-vector/97728)

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**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 6\
**Last updated:** [March 28, 2025, 11:35am UTC](https://discourse.julialang.org/t/brownian-vector/97728 "2025-03-28T11:35:08Z")

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is there a way to create a vector of brownian variables with @brownian, much like one can create vectors of regular variables with @variables? @variables x(t)\[1:N\] y(t)\[1:N\] # works @brownian beta # works @brownian …

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## [Heston SDE exact methods](https://discourse.julialang.org/t/heston-sde-exact-methods/127196)

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**Author:** [@aleCombi](https://discourse.julialang.org/u/aleCombi)\
**Replies:** 5\
**Last updated:** [March 28, 2025, 10:31am UTC](https://discourse.julialang.org/t/heston-sde-exact-methods/127196 "2025-03-28T10:31:04Z")

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I am new to DifferentialEquations.jl and I tried out some SDE simulations with EM. I implemented an exact simulation of Heston SV model using the paper of Broadie and Kaya (https://www.researchgate.net/publication/22024…

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## [CUDA.jl write to global memory in PTX](https://discourse.julialang.org/t/cuda-jl-write-to-global-memory-in-ptx/127426)

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**Author:** [@daniwipes](https://discourse.julialang.org/u/daniwipes)\
**Replies:** 4\
**Last updated:** [March 27, 2025, 9:31pm UTC](https://discourse.julialang.org/t/cuda-jl-write-to-global-memory-in-ptx/127426 "2025-03-27T21:31:18Z")

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I am developing a transpiler for a uni project, that takes an Expr and converts that into PTX code which can then be called to evaluate that expression (in the context of symbolic regression, meaning a lot different valu…

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## [Calculate associated Legendre polynomials on the GPU](https://discourse.julialang.org/t/calculate-associated-legendre-polynomials-on-the-gpu/127418)

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**Author:** [@PetrosStefanou](https://discourse.julialang.org/u/PetrosStefanou)\
**Replies:** 3\
**Last updated:** [March 27, 2025, 7:15pm UTC](https://discourse.julialang.org/t/calculate-associated-legendre-polynomials-on-the-gpu/127418 "2025-03-27T19:15:55Z")

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Hi everyone, I would like to evaluate the associated Legendre polynomials P\_l^m (\\cos{\\theta}) on the GPU. I tried the packages AssociatedLegendrePolynomials.jl and LegendrePolynomials.jl, both of which work as intended…

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## [Save ODE solution for specific values of one state variable](https://discourse.julialang.org/t/save-ode-solution-for-specific-values-of-one-state-variable/126168)

<div class="topic-metadata">

**Author:** [@afossa](https://discourse.julialang.org/u/afossa)\
**Replies:** 2\
**Last updated:** [March 27, 2025, 6:40pm UTC](https://discourse.julialang.org/t/save-ode-solution-for-specific-values-of-one-state-variable/126168 "2025-03-27T18:40:54Z")

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Hello, I am using DifferentialEquations.jl to solve a system of ordinary differential equations (an ODEProblem) of the form du = f(u, p, t) where u is a vector. One component of u, say u\[1\], is monotonically increasing…

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## [Lightweight dependency for GPU programming](https://discourse.julialang.org/t/lightweight-dependency-for-gpu-programming/127386)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 7\
**Last updated:** [March 27, 2025, 5:22pm UTC](https://discourse.julialang.org/t/lightweight-dependency-for-gpu-programming/127386 "2025-03-27T17:22:24Z")

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As a package author is it possible to define KernelAbstractions.jl in my package without adding heavy dependencies? I see that the package currently depends on \[deps\] Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e" Atomi…

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## [Efficient optimization of objective with cos and sin terms](https://discourse.julialang.org/t/efficient-optimization-of-objective-with-cos-and-sin-terms/126990)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 25\
**Last updated:** [March 27, 2025, 1:12am UTC](https://discourse.julialang.org/t/efficient-optimization-of-objective-with-cos-and-sin-terms/126990 "2025-03-27T01:12:03Z")

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Given the following objective: J(t) = ||z\_1 \\cos(t) + z\_2 \\sin(t) - d||\_2^2 with t \\in \[0,2\\pi\] and z\_1,z\_2,d \\in \\mathbb{R}^n. How would you minimize this objective efficiently? I am trying to derive an analytical so…

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## [Approaching a Linear Program Correctly](https://discourse.julialang.org/t/approaching-a-linear-program-correctly/127354)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 15\
**Last updated:** [March 27, 2025, 12:37am UTC](https://discourse.julialang.org/t/approaching-a-linear-program-correctly/127354 "2025-03-27T00:37:32Z")

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Let’s see the Proposition 5.2.1 of the 2009 Bertsekas’s convex optimization theory: (Linear Programming Duality Theorem) (a) If any one of the 2 programs (primal and dual) has a finite optimal objective value, then th…

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## [Plots.jl ylim and yflip don't work together as expected](https://discourse.julialang.org/t/plots-jl-ylim-and-yflip-dont-work-together-as-expected/127394)

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**Author:** [@ayushinav](https://discourse.julialang.org/u/ayushinav)\
**Replies:** 0\
**Last updated:** [March 27, 2025, 12:03am UTC](https://discourse.julialang.org/t/plots-jl-ylim-and-yflip-dont-work-together-as-expected/127394 "2025-03-27T00:03:39Z")

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On Julia 1.11.4, Plots v1.40.11 MWE : using Plots xs = Float64\[1,2,3,4\] ys = Float64\[1,2,3,4,5,6,7,8\] zs = xs'./10 .+ ys p1 = heatmap(xs, ys, zs, title = "original") p2 = heatmap(xs, ys, zs, ylims = (2,4), title = "yl…

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## [Getting JuMP model variables and containers in order of creation](https://discourse.julialang.org/t/getting-jump-model-variables-and-containers-in-order-of-creation/127245)

<div class="topic-metadata">

**Author:** [@brunompacheco](https://discourse.julialang.org/u/brunompacheco)\
**Replies:** 9\
**Last updated:** [March 26, 2025, 10:20pm UTC](https://discourse.julialang.org/t/getting-jump-model-variables-and-containers-in-order-of-creation/127245 "2025-03-26T22:20:28Z")

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Hi! I want to get all variables in my model organized in containers, whenever possible. I am currently using object\_dictionary for that, which seems quite satisfactory, but the order does not follow the creation order, …

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## [User defined operator in JuMP when one of the arguments is data](https://discourse.julialang.org/t/user-defined-operator-in-jump-when-one-of-the-arguments-is-data/127200)

<div class="topic-metadata">

**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 5\
**Last updated:** [March 26, 2025, 9:50pm UTC](https://discourse.julialang.org/t/user-defined-operator-in-jump-when-one-of-the-arguments-is-data/127200 "2025-03-26T21:50:04Z")

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Hi there, I need to solve for a MLE problem where the likelihood function I defined reads in an Array{Obs{Float64}} where Obs{Float64} is an immutable struct containing a bunch of numbers. Since my problem involves a c…

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## [Modeling Toolkit (v8.76) - Change parameters by reference with remake](https://discourse.julialang.org/t/modeling-toolkit-v8-76-change-parameters-by-reference-with-remake/127350)

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**Author:** [@Bill\_Holmes](https://discourse.julialang.org/u/Bill_Holmes)\
**Replies:** 2\
**Last updated:** [March 26, 2025, 1:53pm UTC](https://discourse.julialang.org/t/modeling-toolkit-v8-76-change-parameters-by-reference-with-remake/127350 "2025-03-26T13:53:57Z")

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Hello all. I have a question about using remake on an ODEproblem constructed using modeling toolkit (MTK). I’ll note that I’m using MTK v8.76.0. I am aware that v9 introduces new structure referencing (Frequently Asked Q…

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## [How to install DSDP.jl](https://discourse.julialang.org/t/how-to-install-dsdp-jl/33033)

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**Author:** [@tdp](https://discourse.julialang.org/u/tdp)\
**Replies:** 3\
**Last updated:** [March 26, 2025, 1:30pm UTC](https://discourse.julialang.org/t/how-to-install-dsdp-jl/33033 "2025-03-26T13:30:47Z")

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Hi, When trying to install DSDP.jl using the command below, I get the error below about incompatible versions for MathOptInterface. How would I resolve this? I have version 0.99 of MathOptInterface and version 1.3.0 of…

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## [Makie Visualization for Planetary Simulation for High School Students](https://discourse.julialang.org/t/makie-visualization-for-planetary-simulation-for-high-school-students/126811)

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**Author:** [@roflmaostc](https://discourse.julialang.org/u/roflmaostc)\
**Replies:** 8\
**Last updated:** [March 26, 2025, 12:31pm UTC](https://discourse.julialang.org/t/makie-visualization-for-planetary-simulation-for-high-school-students/126811 "2025-03-26T12:31:58Z")

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Hi, I am going to teach some simple orbital dynamics to high school students in summer. The students are going to implement the gravitational forces and some sort of time integration (simple explicit or implicit euler)…

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## [HTCondor workflow for "embarrassingly" parallel computations](https://discourse.julialang.org/t/htcondor-workflow-for-embarrassingly-parallel-computations/127314)

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**Author:** [@alexdmeyer](https://discourse.julialang.org/u/alexdmeyer)\
**Replies:** 1\
**Last updated:** [March 26, 2025, 12:40am UTC](https://discourse.julialang.org/t/htcondor-workflow-for-embarrassingly-parallel-computations/127314 "2025-03-26T00:40:44Z")

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Hey Julia Community, I’m currently using HTCondor to run batches of jobs on my university’s computing cluster. The problem I’m working on is “embarrassingly” (a.k.a. “pleasingly”) parallel, in that each job does the sam…

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## [Question on programmatically defining a nonlinear expression involving product and sum](https://discourse.julialang.org/t/question-on-programmatically-defining-a-nonlinear-expression-involving-product-and-sum/127330)

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**Author:** [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)\
**Replies:** 9\
**Last updated:** [March 25, 2025, 7:12pm UTC](https://discourse.julialang.org/t/question-on-programmatically-defining-a-nonlinear-expression-involving-product-and-sum/127330 "2025-03-25T19:12:58Z")

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I have a n-dimensional vector m, a set of JuMP variables defined by \\{x\_{i,k\_{i}}\\}\_{i\\in\\{1,2,\\ldots,n\\},k\_{i}\\in\\{1,2,\\ldots,m\_{i}\\}}=\\{x\_{1,1},x\_{1,2},\\ldots,x\_{1,m\_{1}},x\_{2,1},x\_{2,2},\\ldots,x\_{2,m\_{2}},\\ldots,x\_{…

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## [BilevelJuMP: Symmetric variables not supported?](https://discourse.julialang.org/t/bileveljump-symmetric-variables-not-supported/127346)

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**Author:** [@HSt](https://discourse.julialang.org/u/HSt)\
**Replies:** 1\
**Last updated:** [March 25, 2025, 6:58pm UTC](https://discourse.julialang.org/t/bileveljump-symmetric-variables-not-supported/127346 "2025-03-25T18:58:47Z")

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I’ve build functions to add specific variables and constraints one after another, to modularize model creation. Some of the variables should be symmetric, which is fine in regular JuMP when constrained on creation. How…

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## [Integrating over piecewise approxfun](https://discourse.julialang.org/t/integrating-over-piecewise-approxfun/127309)

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**Author:** [@nilsbecker](https://discourse.julialang.org/u/nilsbecker)\
**Replies:** 8\
**Last updated:** [March 25, 2025, 4:08pm UTC](https://discourse.julialang.org/t/integrating-over-piecewise-approxfun/127309 "2025-03-25T16:08:26Z")

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Following up on my earlier post, I now have an ApproxFun.jl Fun defined over a piecewise domain: using ApproxFun f\_pw = Fun(x -\> (x \< 1.0 ? exp(x) : 1.), union(Segment(0.,1.), Segment(1.,2.))) f\_pw\_i = integrate(f\_pw) T…

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## [Minimum Spanning Tree Problem - Constrained by total edge sum](https://discourse.julialang.org/t/minimum-spanning-tree-problem-constrained-by-total-edge-sum/127351)

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**Author:** [@mast-lfl](https://discourse.julialang.org/u/mast-lfl)\
**Replies:** 2\
**Last updated:** [March 25, 2025, 3:32pm UTC](https://discourse.julialang.org/t/minimum-spanning-tree-problem-constrained-by-total-edge-sum/127351 "2025-03-25T15:32:21Z")

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Assume that I have an undirected graph. Several of the vertices in the graph serve as waste disposal sites, while the other vertices produce the waste. Producing vertices have a weight (corresponding to the amount of was…

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## [Solution not converging for advection PDE](https://discourse.julialang.org/t/solution-not-converging-for-advection-pde/123349)

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**Author:** [@Alma\_Thindberg](https://discourse.julialang.org/u/Alma_Thindberg)\
**Replies:** 9\
**Last updated:** [March 25, 2025, 1:05pm UTC](https://discourse.julialang.org/t/solution-not-converging-for-advection-pde/123349 "2025-03-25T13:05:01Z")

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using Pkg #Pkg.add("ModelingToolkit") #Pkg.add("MethodOfLines") #Pkg.add("DomainSets") #Pkg.add("OrdinaryDiffEq") Pkg.add("NonlinearSolve") using ModelingToolkit, MethodOfLines, DomainSets, OrdinaryDiffEq, LinearAlge…

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## [A naive explanation of infeasibility and unboundedness](https://discourse.julialang.org/t/a-naive-explanation-of-infeasibility-and-unboundedness/127343)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 1\
**Last updated:** [March 25, 2025, 12:37pm UTC](https://discourse.julialang.org/t/a-naive-explanation-of-infeasibility-and-unboundedness/127343 "2025-03-25T12:37:48Z")

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I demo the process “From unboundedness to an infeasibility system” Say, let’s employ y \\in \\mathbb{R} as our decision variable. We know +\\infty = \\sup \\{y | y \\ge 0\\} Given any y \\ge 0, we know 0 = \\inf \\{yx |x \\g…

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## [How to link color axes of heatmaps?](https://discourse.julialang.org/t/how-to-link-color-axes-of-heatmaps/62511)

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**Author:** [@ericphanson](https://discourse.julialang.org/u/ericphanson)\
**Replies:** 5\
**Last updated:** [March 25, 2025, 12:37pm UTC](https://discourse.julialang.org/t/how-to-link-color-axes-of-heatmaps/62511 "2025-03-25T12:37:46Z")

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For example, using CairoMakie function testfig() fig = Figure() heatmaps = \[\] for i = 1:4 h = heatmap!(Axis(fig\[i, 1\]), i .+ rand(200, 200)) push!(heatmaps, h) end Colorbar(fig\[:, 2\],…

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## [Solving large scale NLP problem on HPC cluster](https://discourse.julialang.org/t/solving-large-scale-nlp-problem-on-hpc-cluster/127134)

<div class="topic-metadata">

**Author:** [@J-Holger](https://discourse.julialang.org/u/J-Holger)\
**Replies:** 5\
**Last updated:** [March 25, 2025, 8:50am UTC](https://discourse.julialang.org/t/solving-large-scale-nlp-problem-on-hpc-cluster/127134 "2025-03-25T08:50:42Z")

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Hello, I’m trying to solve a maximization problem for maximizing profit in river hydroelectricity power production. The problem is non-linear and non-convex. I’m using the solution from a simplified, linear and convex, …

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