# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=164

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**Page:** 165

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## [I wanted to generate a contour plot for 2D heat conduction by neural PDE but this code generates blank plot without any contour](https://discourse.julialang.org/t/i-wanted-to-generate-a-contour-plot-for-2d-heat-conduction-by-neural-pde-but-this-code-generates-blank-plot-without-any-contour/103960)

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**Author:** [@ShadmanSakief](https://discourse.julialang.org/u/ShadmanSakief)\
**Replies:** 3\
**Last updated:** [September 25, 2023, 12:03pm UTC](https://discourse.julialang.org/t/i-wanted-to-generate-a-contour-plot-for-2d-heat-conduction-by-neural-pde-but-this-code-generates-blank-plot-without-any-contour/103960 "2023-09-25T12:03:54Z")

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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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## [Creating Matrix Parameters in JuMP](https://discourse.julialang.org/t/creating-matrix-parameters-in-jump/104159)

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**Author:** [@Three](https://discourse.julialang.org/u/Three)\
**Replies:** 3\
**Last updated:** [September 24, 2023, 6:05pm UTC](https://discourse.julialang.org/t/creating-matrix-parameters-in-jump/104159 "2023-09-24T18:05:46Z")

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Hello, Sorry if this is a dumb question, but I can’t figure out how to declare a matrix (or higher dimensional array) variable that is constrained to a parameter set in JuMP, as shown for the vector case here: Variables…

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## [Suppressing automatic display(::Makie.Scene) in the REPL](https://discourse.julialang.org/t/suppressing-automatic-display-makie-scene-in-the-repl/103543)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 3\
**Last updated:** [September 24, 2023, 3:29pm UTC](https://discourse.julialang.org/t/suppressing-automatic-display-makie-scene-in-the-repl/103543 "2023-09-24T15:29:26Z")

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A common occurrence when I’m working on Makie stuff at the REPL: julia\> foo = some\_function\_that\_returns\_a\_scene() Error showing value of type Makie.Scene: ERROR: AssertionError: internal error. Scene already displayed …

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## [How do I make sure my optimization problem doesn’t get NP-hard?](https://discourse.julialang.org/t/how-do-i-make-sure-my-optimization-problem-doesn-t-get-np-hard/104190)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 1\
**Last updated:** [September 24, 2023, 6:32am UTC](https://discourse.julialang.org/t/how-do-i-make-sure-my-optimization-problem-doesn-t-get-np-hard/104190 "2023-09-24T06:32:57Z")

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It’s quite easy to get some NP-hard instance of a problem, for example… maximize ax1^2 + bx1x2 + cx1x3 + … somethingx2x3 + somethingx2x4 + … Subject to all variables between some values and some values… Alone is NP ha…

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## [Connecting components by adding term to DE in ModelingToolkit](https://discourse.julialang.org/t/connecting-components-by-adding-term-to-de-in-modelingtoolkit/104149)

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**Author:** [@nkoch](https://discourse.julialang.org/u/nkoch)\
**Replies:** 2\
**Last updated:** [September 24, 2023, 2:45am UTC](https://discourse.julialang.org/t/connecting-components-by-adding-term-to-de-in-modelingtoolkit/104149 "2023-09-24T02:45:00Z")

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I am trying to connect components by adding function of variables from each component to one of the DEs in each component. In other words, for components 1 and 2 (and their respective variables z\_1 and z\_2) \\frac{d z\_1}…

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## [Makie: one (nice?) way to control the units of axes](https://discourse.julialang.org/t/makie-one-nice-way-to-control-the-units-of-axes/103999)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 9\
**Last updated:** [September 23, 2023, 5:51am UTC](https://discourse.julialang.org/t/makie-one-nice-way-to-control-the-units-of-axes/103999 "2023-09-23T05:51:09Z")

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Suppose we have (x,y) data following y = f(x), x is measured in centimeters, and y is measured in micrometers. When plotting the (x,y) data, we would want to show the x-axis in centimeters and the y-axis in micrometers,…

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## [Lyapunov + Symmetries = Infeasible, Lyapunov - Symmetries = Feasible](https://discourse.julialang.org/t/lyapunov-symmetries-infeasible-lyapunov-symmetries-feasible/101585)

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**Author:** [@ilovemath](https://discourse.julialang.org/u/ilovemath)\
**Replies:** 9\
**Last updated:** [September 22, 2023, 11:21pm UTC](https://discourse.julialang.org/t/lyapunov-symmetries-infeasible-lyapunov-symmetries-feasible/101585 "2023-09-22T23:21:44Z")

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Hi again @blegat @abulak I am using SOS programming to find a Lyapunov function, obeying some natural symmetry. The time derivative of V also obeys said symmetry. The feasibility of the Lyapunov function is dependent …

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## [Inconsistent matrix multiply output from Flux.Dense depending on shape of input](https://discourse.julialang.org/t/inconsistent-matrix-multiply-output-from-flux-dense-depending-on-shape-of-input/104116)

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**Author:** [@JuliaMLTools](https://discourse.julialang.org/u/JuliaMLTools)\
**Replies:** 11\
**Last updated:** [September 22, 2023, 3:05pm UTC](https://discourse.julialang.org/t/inconsistent-matrix-multiply-output-from-flux-dense-depending-on-shape-of-input/104116 "2023-09-22T15:05:15Z")

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Anyone know a workaround for this inconsistency in matrix multiply?

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## [Comparison of plotting packages](https://discourse.julialang.org/t/comparison-of-plotting-packages/99860)

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**Author:** [@hros](https://discourse.julialang.org/u/hros)\
**Replies:** 75\
**Last updated:** [September 22, 2023, 8:13am UTC](https://discourse.julialang.org/t/comparison-of-plotting-packages/99860 "2023-09-22T08:13:00Z")

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I want to write a small 2d physical simulation to sharpen my Julia skills and learn how to use Julia to display more than “regular plots” I saw a post suggesting using either Makie, Plots or Javis I don’t want to start…

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## [Are \`GNNHeteroGraph\` like labeled property graphs?](https://discourse.julialang.org/t/are-gnnheterograph-like-labeled-property-graphs/104131)

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**Author:** [@huguesmp](https://discourse.julialang.org/u/huguesmp)\
**Replies:** 0\
**Last updated:** [September 22, 2023, 12:19am UTC](https://discourse.julialang.org/t/are-gnnheterograph-like-labeled-property-graphs/104131 "2023-09-22T00:19:34Z")

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While reading the documentation for GraphNeuralNetworks.jl, the section on heterogeneous graphs caught my eye. With their typed nodes and relationships, they look and feel a little bit like labeled property graphs, as u…

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## [ERROR VariableNotOwned{VariableRef} when using add\_constraint](https://discourse.julialang.org/t/error-variablenotowned-variableref-when-using-add-constraint/104043)

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**Author:** [@Luiz\_Monteiro](https://discourse.julialang.org/u/Luiz_Monteiro)\
**Replies:** 3\
**Last updated:** [September 21, 2023, 9:26pm UTC](https://discourse.julialang.org/t/error-variablenotowned-variableref-when-using-add-constraint/104043 "2023-09-21T21:26:33Z")

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Hi, I am tryng to solve a MIP model (VRP) by solving a relaxed version of the model and repeatedly identifying violated contraints and adding those contraints to the model using add\_constraint(model1, cons). But I get …

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## [Parameter optimization using Multiple shooting](https://discourse.julialang.org/t/parameter-optimization-using-multiple-shooting/104104)

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**Author:** [@Marco\_Nesta](https://discourse.julialang.org/u/Marco_Nesta)\
**Replies:** 1\
**Last updated:** [September 21, 2023, 12:18pm UTC](https://discourse.julialang.org/t/parameter-optimization-using-multiple-shooting/104104 "2023-09-21T12:18:19Z")

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'm using the same structure as in the link, but how can I view the updated parameters? this is my code: using DifferentialEquations, Plots, Flux,Optim, DiffEqFlux, DataInterpolations,Random, ComponentArrays, Lux …

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## [How to exchange x and y axis in band plot](https://discourse.julialang.org/t/how-to-exchange-x-and-y-axis-in-band-plot/104090)

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**Author:** [@subsnutr](https://discourse.julialang.org/u/subsnutr)\
**Replies:** 3\
**Last updated:** [September 21, 2023, 7:24am UTC](https://discourse.julialang.org/t/how-to-exchange-x-and-y-axis-in-band-plot/104090 "2023-09-21T07:24:18Z")

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Dear all Is there a way to exchange x and y axis in band plot in Makie.jl? For example, I want to have band(y,xlower,xupper) Thanks!

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## [Using @view with CuArrays](https://discourse.julialang.org/t/using-view-with-cuarrays/104057)

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**Author:** [@Kieran\_Marray](https://discourse.julialang.org/u/Kieran_Marray)\
**Replies:** 6\
**Last updated:** [September 20, 2023, 8:52pm UTC](https://discourse.julialang.org/t/using-view-with-cuarrays/104057 "2023-09-20T20:52:34Z")

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Hi. I am new to GPU programming with Julia, and trying to run a matrix multiplication within a loop. It is important this is performant, so want to minimise allocations. But if I run the following minimal example (as I w…

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## [BilevelJuMP and Lazy cns with Gurobi](https://discourse.julialang.org/t/bileveljump-and-lazy-cns-with-gurobi/104060)

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**Author:** [@Fabrizio](https://discourse.julialang.org/u/Fabrizio)\
**Replies:** 1\
**Last updated:** [September 20, 2023, 8:25pm UTC](https://discourse.julialang.org/t/bileveljump-and-lazy-cns-with-gurobi/104060 "2023-09-20T20:25:00Z")

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I repost this here for conveniece Dear all, when using pure Jump model i exensively use the lazy attribute with some cns using Gurobi as a solver with the syntiax MOI.set(MyMod, Gurobi.ConstraintAttribute(“Lazy”), Cn…

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## [Struggling to load a pre-trained PyTorch model into Julia](https://discourse.julialang.org/t/struggling-to-load-a-pre-trained-pytorch-model-into-julia/104068)

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**Author:** [@Jian\_ZUO](https://discourse.julialang.org/u/Jian_ZUO)\
**Replies:** 2\
**Last updated:** [September 20, 2023, 7:34pm UTC](https://discourse.julialang.org/t/struggling-to-load-a-pre-trained-pytorch-model-into-julia/104068 "2023-09-20T19:34:24Z")

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Hi all, I am coming back to this unsolved problem. The background is that I have trained a reinforcement learning agent and I want to load the pre-trained model (pytorch) into Julia for inference (it is much faster to …

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## [RigidBodySim.jl pkg issues](https://discourse.julialang.org/t/rigidbodysim-jl-pkg-issues/104073)

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**Author:** [@jondavis847](https://discourse.julialang.org/u/jondavis847)\
**Replies:** 0\
**Last updated:** [September 20, 2023, 6:16pm UTC](https://discourse.julialang.org/t/rigidbodysim-jl-pkg-issues/104073 "2023-09-20T18:16:10Z")

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I’m starting out with RigidBodyDynamics.jl and can successfully create and sim models in its environment. I’d like to try RigidBodySim.jl, mostly for the interface to DifferentialEquations.jl for its problem types and so…

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## [XML to DataFrame converter](https://discourse.julialang.org/t/xml-to-dataframe-converter/104040)

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**Author:** [@tp2750](https://discourse.julialang.org/u/tp2750)\
**Replies:** 6\
**Last updated:** [September 20, 2023, 6:14pm UTC](https://discourse.julialang.org/t/xml-to-dataframe-converter/104040 "2023-09-20T18:14:03Z")

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Many instruments write data in XML format, and I often find that I spend way too much time writing parsers to convert it to DataFrame. Do we have a package that can take a file like this: \<?xml version="1.0" encoding="…

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## [Instabilities on a simple dataset when training a NODE on it](https://discourse.julialang.org/t/instabilities-on-a-simple-dataset-when-training-a-node-on-it/103916)

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**Author:** [@jarroyoe](https://discourse.julialang.org/u/jarroyoe)\
**Replies:** 5\
**Last updated:** [September 20, 2023, 4:50pm UTC](https://discourse.julialang.org/t/instabilities-on-a-simple-dataset-when-training-a-node-on-it/103916 "2023-09-20T16:50:28Z")

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I have an extremely simple dataset that for some reason keeps outputing instabilities when trying to train a NODE algorithm on it, no matter how low the tolerance is set or what solver I choose. I train it twice, once wi…

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## [Saving and loading architectures with multiple blocks](https://discourse.julialang.org/t/saving-and-loading-architectures-with-multiple-blocks/104030)

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**Author:** [@tom-plaa](https://discourse.julialang.org/u/tom-plaa)\
**Replies:** 3\
**Last updated:** [September 20, 2023, 3:49pm UTC](https://discourse.julialang.org/t/saving-and-loading-architectures-with-multiple-blocks/104030 "2023-09-20T15:49:25Z")

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Hi! I’m working on a project where another person has been trying out different architectures in Flux.jl for a given problem, and the one that turned out to be the best one is giving us problems when saving and loading …

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## [Programmatically creating parameters in ModelingToolkit.jl leads to unexpected outcome](https://discourse.julialang.org/t/programmatically-creating-parameters-in-modelingtoolkit-jl-leads-to-unexpected-outcome/104063)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 5\
**Last updated:** [September 20, 2023, 2:03pm UTC](https://discourse.julialang.org/t/programmatically-creating-parameters-in-modelingtoolkit-jl-leads-to-unexpected-outcome/104063 "2023-09-20T14:03:06Z")

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I am trying to create programmatically a parameter (with @parameter) with ModelingToolkit.jl. While I am succeeding, the outcome is not exactly what I wish for. Here are the two examples: @variables t # indep…

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## [Angular Momentum Commutators In Symbolics.jl](https://discourse.julialang.org/t/angular-momentum-commutators-in-symbolics-jl/103493)

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**Author:** [@wes648](https://discourse.julialang.org/u/wes648)\
**Replies:** 2\
**Last updated:** [September 20, 2023, 1:21pm UTC](https://discourse.julialang.org/t/angular-momentum-commutators-in-symbolics-jl/103493 "2023-09-20T13:21:59Z")

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Could I get some help defining the angular momentum commutators symbolicaly in Julia? I’ve tried using SymbolicUtils @acrules to define Nx\*Ny - Ny\*Nx =\> im\*Nz but then when I run Nx\*Ny - Ny\*Nx it returns zero. I also tr…

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## [\`tstop\` error with Piecewise Deterministic Markov Processes](https://discourse.julialang.org/t/tstop-error-with-piecewise-deterministic-markov-processes/104031)

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**Author:** [@cdawg](https://discourse.julialang.org/u/cdawg)\
**Replies:** 7\
**Last updated:** [September 20, 2023, 11:10am UTC](https://discourse.julialang.org/t/tstop-error-with-piecewise-deterministic-markov-processes/104031 "2023-09-20T11:10:53Z")

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I’m asking for help for an annoying, (ironically) non-deterministic error when I solve Jumpy-ODE’s (i.e. “Piecewise Deterministic Markov Processes”). It tends to start happening as I increase the number of processes and …

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## [Does SCIP.jl use PaPILO for presolve by default?](https://discourse.julialang.org/t/does-scip-jl-use-papilo-for-presolve-by-default/104046)

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**Author:** [@convexhull](https://discourse.julialang.org/u/convexhull)\
**Replies:** 3\
**Last updated:** [September 20, 2023, 6:20am UTC](https://discourse.julialang.org/t/does-scip-jl-use-papilo-for-presolve-by-default/104046 "2023-09-20T06:20:40Z")

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I’m using SCIP and JuMP to solve a MILP and I’m interested in using PaPILO to see if it can help to strengthen my formulation. I’ve never used PaPILO before. SCIP’s solve output shows a presolve step, but I’m unsure wha…

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## [Calculating Rate of change by year for each sector](https://discourse.julialang.org/t/calculating-rate-of-change-by-year-for-each-sector/104048)

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**Author:** [@nnguyengiatan](https://discourse.julialang.org/u/nnguyengiatan)\
**Replies:** 1\
**Last updated:** [September 20, 2023, 4:26am UTC](https://discourse.julialang.org/t/calculating-rate-of-change-by-year-for-each-sector/104048 "2023-09-20T04:26:00Z")

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Hi all, I have dataframes as follow: Row │ year sector roa │ Int64 String Float64 ─────┼───────────────────────────────────────── 1 │ 2017 Construction …

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## [How to Maintain Cookies and Sessions Across Multiple Requests Using HTTP.jl?](https://discourse.julialang.org/t/how-to-maintain-cookies-and-sessions-across-multiple-requests-using-http-jl/104004)

<div class="topic-metadata">

**Author:** [@Thiago-Simoes](https://discourse.julialang.org/u/Thiago-Simoes)\
**Replies:** 1\
**Last updated:** [September 19, 2023, 9:31pm UTC](https://discourse.julialang.org/t/how-to-maintain-cookies-and-sessions-across-multiple-requests-using-http-jl/104004 "2023-09-19T21:31:21Z")

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I’m working on a project in Julia and I’m using the HTTP.jl package for handling HTTP requests. I’m wondering how I can create a connection and make multiple requests while maintaining cookies and session data. Specifica…

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## [Solving multiple similar problems in JuMP](https://discourse.julialang.org/t/solving-multiple-similar-problems-in-jump/103980)

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**Author:** [@Three](https://discourse.julialang.org/u/Three)\
**Replies:** 8\
**Last updated:** [September 19, 2023, 9:13pm UTC](https://discourse.julialang.org/t/solving-multiple-similar-problems-in-jump/103980 "2023-09-19T21:13:33Z")

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Hello, I’m interested in using JuMP to solve series of (all nonlinear) problems with identical constraints but different objectives. Is it possible to speed this up over the naive approach of just defining each problem …

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## [Colorbar with function range for a 3D contour plot using GLMakie](https://discourse.julialang.org/t/colorbar-with-function-range-for-a-3d-contour-plot-using-glmakie/103388)

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**Author:** [@Olegg](https://discourse.julialang.org/u/Olegg)\
**Replies:** 5\
**Last updated:** [September 19, 2023, 12:25pm UTC](https://discourse.julialang.org/t/colorbar-with-function-range-for-a-3d-contour-plot-using-glmakie/103388 "2023-09-19T12:25:04Z")

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I’m trying to add a colorbar to a 3D contour plot in GLMakie with the actual range of the function values. However, the colorbar I get only shows a range from 0 to 1, while the actual range is \[-0.7, 0.7\]. Here is the c…

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## [Updating a volume plot](https://discourse.julialang.org/t/updating-a-volume-plot/103987)

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**Author:** [@Knud\_Sorensen](https://discourse.julialang.org/u/Knud_Sorensen)\
**Replies:** 2\
**Last updated:** [September 19, 2023, 12:07pm UTC](https://discourse.julialang.org/t/updating-a-volume-plot/103987 "2023-09-19T12:07:46Z")

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Hi. I am plotting a volume plot. Like volume(vol; algorithm=:absorption) But I want to update the plot with new data (nvol)! But when I run volume!(nvol; algorithm=:absorption) it adds the new data to the old data in…

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## [How to determine what size and how many textures I can use?](https://discourse.julialang.org/t/how-to-determine-what-size-and-how-many-textures-i-can-use/104018)

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**Author:** [@lodygaw](https://discourse.julialang.org/u/lodygaw)\
**Replies:** 1\
**Last updated:** [September 19, 2023, 11:04am UTC](https://discourse.julialang.org/t/how-to-determine-what-size-and-how-many-textures-i-can-use/104018 "2023-09-19T11:04:53Z")

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Hi, Is there a way to determine (programmatically) what is the maximum size of 1D texture array for particular device? Is there any limitation how many texture arrays can be used in total?

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