# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=115

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**Page:** 116

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## [ModelingToolkit @mtkmodel and loop on equations](https://discourse.julialang.org/t/modelingtoolkit-mtkmodel-and-loop-on-equations/113374)

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**Author:** [@julien-dc](https://discourse.julialang.org/u/julien-dc)\
**Replies:** 3\
**Last updated:** [April 29, 2024, 5:16am UTC](https://discourse.julialang.org/t/modelingtoolkit-mtkmodel-and-loop-on-equations/113374 "2024-04-29T05:16:56Z")

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Greetings Julia community, I’m currently exploring the possibility of transitioning from a Modelica/Python workflow to a fully Julia-based workflow for my projects. As I’m relatively new to Julia, I’ve encountered an is…

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## [Tools for computer assisted proofs in analysis](https://discourse.julialang.org/t/tools-for-computer-assisted-proofs-in-analysis/113479)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 13\
**Last updated:** [April 29, 2024, 12:19am UTC](https://discourse.julialang.org/t/tools-for-computer-assisted-proofs-in-analysis/113479 "2024-04-29T00:19:30Z")

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I wanted to ask somewhat open-ended on what tools and packages exist in julia (and outside of julia) for computer assisted “numerical” proofs, and whether you know of examples where this has been done in the julia ecosys…

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## [Monitoring the progress of DiffEq solve](https://discourse.julialang.org/t/monitoring-the-progress-of-diffeq-solve/113579)

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**Author:** [@cuihantao](https://discourse.julialang.org/u/cuihantao)\
**Replies:** 5\
**Last updated:** [April 28, 2024, 10:35pm UTC](https://discourse.julialang.org/t/monitoring-the-progress-of-diffeq-solve/113579 "2024-04-28T22:35:11Z")

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The motivation is that, sometimes, solve(prob) takes long time to run. While running, DiffEq doesn’t print any output (even with debug logging on). There is no easy way to tell what’s going on, e.g., if it’s stuck at a …

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## [Simulating a stochastic volatility model with jumps using DifferentialEquations.jl and JumpProcesses.jl](https://discourse.julialang.org/t/simulating-a-stochastic-volatility-model-with-jumps-using-differentialequations-jl-and-jumpprocesses-jl/113534)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 4\
**Last updated:** [April 28, 2024, 12:46pm UTC](https://discourse.julialang.org/t/simulating-a-stochastic-volatility-model-with-jumps-using-differentialequations-jl-and-jumpprocesses-jl/113534 "2024-04-28T12:46:29Z")

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I’ve been using DifferentialEquations.jl to simulate the following stochastic volatility model: du\_t = 0 dt + v\_t ( -0.576 dW\_{1,t} + \\sqrt{1 - 0.576^2} dW\_{2,t}) dv\_t^2 = 0.035 (0.636 - v\_t^2) dt + 0 . 144 v\_t^2 dW\_{1…

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## [Is there a tutorial on \`JuMP\` extension development?](https://discourse.julialang.org/t/is-there-a-tutorial-on-jump-extension-development/113580)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 2\
**Last updated:** [April 28, 2024, 6:20am UTC](https://discourse.julialang.org/t/is-there-a-tutorial-on-jump-extension-development/113580 "2024-04-28T06:20:53Z")

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Is there a tutorial on JuMP extension development? I’m curious about how to transform a naturally written model (similar to the JuMP modeling language) into a standardized format that is suitable for algorithmic solving. …

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## [How to extract the indices of a certain variable from a \`Vector{VariableRef}\`?](https://discourse.julialang.org/t/how-to-extract-the-indices-of-a-certain-variable-from-a-vector-variableref/113555)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 2\
**Last updated:** [April 28, 2024, 3:21am UTC](https://discourse.julialang.org/t/how-to-extract-the-indices-of-a-certain-variable-from-a-vector-variableref/113555 "2024-04-28T03:21:30Z")

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using JuMP m = Model() @variable(m, x\[1:3\]) @variable(m, y\[1:5\]) v = all\_variables(m) v is an 8-element Vector{VariableRef}. Now I want to extract all the indices with respect to variable y from the vector v (e.g., it c…

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## [How to eliminate a variable from a JuMP model?](https://discourse.julialang.org/t/how-to-eliminate-a-variable-from-a-jump-model/113557)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 1\
**Last updated:** [April 27, 2024, 10:30pm UTC](https://discourse.julialang.org/t/how-to-eliminate-a-variable-from-a-jump-model/113557 "2024-04-27T22:30:01Z")

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For example, with the help of Polyhedra.jl one can eliminate variable y from model m (or project m onto x space) and obtain a polyhedron P with respect to x: using JuMP, Polyhedra, CDDLib m = Model() @variable(m, x) @va…

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## [Lambda Systems](https://discourse.julialang.org/t/lambda-systems/113572)

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**Author:** [@avishipoddar](https://discourse.julialang.org/u/avishipoddar)\
**Replies:** 6\
**Last updated:** [April 27, 2024, 7:41pm UTC](https://discourse.julialang.org/t/lambda-systems/113572 "2024-04-27T19:41:02Z")

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I am trying to simulate a 3-level lambda system. I have defined the operators such as sigma\_ee, sigma\_es, sigma\_eg, etc. as 3-level matrices. To build the Hamiltonian as an MPO, do I use spin-1?

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## [Help using CUDA to exponentiate Matrix](https://discourse.julialang.org/t/help-using-cuda-to-exponentiate-matrix/113548)

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**Author:** [@ShaswataRoy](https://discourse.julialang.org/u/ShaswataRoy)\
**Replies:** 3\
**Last updated:** [April 27, 2024, 2:46pm UTC](https://discourse.julialang.org/t/help-using-cuda-to-exponentiate-matrix/113548 "2024-04-27T14:46:14Z")

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I am trying to use CUDA to speed up the process of finding the exponential of a matrix. For some reason, all the steps are fast except the code written inside a loop using LinearAlgebra using SparseArrays using CUDA us…

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## [Connect points in for loop](https://discourse.julialang.org/t/connect-points-in-for-loop/113429)

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**Author:** [@Sharara](https://discourse.julialang.org/u/Sharara)\
**Replies:** 15\
**Last updated:** [April 27, 2024, 12:00pm UTC](https://discourse.julialang.org/t/connect-points-in-for-loop/113429 "2024-04-27T12:00:02Z")

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Dear all I am using PlotlyJS (I need its interactivity) it is my code: k1 = equ1 k2 = equ2 k3 = equ3 k4 = equ4 push!(k1\_x, real(k1)) push!(k1\_y, imag(k1)) push!(k2\_x, real(k2)) push!(k2\_y, imag(k2)) push!(k3\_x, real(…

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## [Any qualifier in CUDA.jl like \`\_\_device\_\_\` in CUDA/C++?](https://discourse.julialang.org/t/any-qualifier-in-cuda-jl-like-device-in-cuda-c/113517)

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**Author:** [@huiyuxie](https://discourse.julialang.org/u/huiyuxie)\
**Replies:** 6\
**Last updated:** [April 26, 2024, 4:20pm UTC](https://discourse.julialang.org/t/any-qualifier-in-cuda-jl-like-device-in-cuda-c/113517 "2024-04-26T16:20:51Z")

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Hi all! I was wondering is there any qualifier in CUDA.jl like \_\_device\_\_ in CUDA/C++ to calling a function from device to make sure the function call is not falling back to CPU. For example, using CUDA function gpu\_a…

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## [Plots (plotly) multiple series or line labels in legend](https://discourse.julialang.org/t/plots-plotly-multiple-series-or-line-labels-in-legend/13001)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 3\
**Last updated:** [April 26, 2024, 3:24pm UTC](https://discourse.julialang.org/t/plots-plotly-multiple-series-or-line-labels-in-legend/13001 "2024-04-26T15:24:04Z")

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how does one label two lines? using Plots; pyplot() plot(Plots.fakedata(50,2), w=3, labels=\[ "a", "b" \]) the blue line is not labeled “a” and the red line is not labeled “b” . PS: Overview · Plots writes “if label is …

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## [Best free SDP, JuMP supported solvers?](https://discourse.julialang.org/t/best-free-sdp-jump-supported-solvers/102413)

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**Author:** [@nlaws](https://discourse.julialang.org/u/nlaws)\
**Replies:** 8\
**Last updated:** [April 26, 2024, 3:01pm UTC](https://discourse.julialang.org/t/best-free-sdp-jump-supported-solvers/102413 "2024-04-26T15:01:41Z")

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There are quite a few free SDP solvers listed in the supported JuMP solvers. I’m wondering (even if just anecdotally) what other’s experiences are like and what folks have found to work well? I have tried maybe half of t…

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## [AoG/Makie: Axis sorted in alphabetical order](https://discourse.julialang.org/t/aog-makie-axis-sorted-in-alphabetical-order/113527)

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**Author:** [@gruemelmonster](https://discourse.julialang.org/u/gruemelmonster)\
**Replies:** 2\
**Last updated:** [April 26, 2024, 12:39pm UTC](https://discourse.julialang.org/t/aog-makie-axis-sorted-in-alphabetical-order/113527 "2024-04-26T12:39:55Z")

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I am trying to plot some measurement data using AoG. I am also pretty new to this, so I might be missing something obvious. When I try to plot data that has string entries as an X-Axis, the values get sorted by alphabet…

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## [Weighted PCA with MultivariateStats.jl](https://discourse.julialang.org/t/weighted-pca-with-multivariatestats-jl/113525)

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**Author:** [@njacki](https://discourse.julialang.org/u/njacki)\
**Replies:** 0\
**Last updated:** [April 26, 2024, 9:26am UTC](https://discourse.julialang.org/t/weighted-pca-with-multivariatestats-jl/113525 "2024-04-26T09:26:54Z")

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Hi, I want to perfrom PCA on my dataset and assign possible different weights to my variables. According to Jolliffe (2002), this can be easily done when the weighting matrix can be factorized, i.e., W\_{ij} = \\omega\_i …

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## [Makie Layout Text Over Column of Plots](https://discourse.julialang.org/t/makie-layout-text-over-column-of-plots/113509)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 2\
**Last updated:** [April 25, 2024, 4:37pm UTC](https://discourse.julialang.org/t/makie-layout-text-over-column-of-plots/113509 "2024-04-25T16:37:27Z")

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Hello, I am trying to show the evolution of a quantity via a series of plots. I have three simulations which describe something changing with time. I want to show side by side comparisons at various times. So my idea is…

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## [How can I achieve this Makie Layout that respects a given aspect ratio?](https://discourse.julialang.org/t/how-can-i-achieve-this-makie-layout-that-respects-a-given-aspect-ratio/113490)

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**Author:** [@tscode](https://discourse.julialang.org/u/tscode)\
**Replies:** 4\
**Last updated:** [April 25, 2024, 2:48pm UTC](https://discourse.julialang.org/t/how-can-i-achieve-this-makie-layout-that-respects-a-given-aspect-ratio/113490 "2024-04-25T14:48:55Z")

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I want to make the following layout behave sensibly under changes of the figure size (interactive settings mainly). The constraints are: The green column has a fixed width. The red box has a given aspect ratio (1 in…

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## [Multiple GPUs with CuStateVec in CUDA.jl](https://discourse.julialang.org/t/multiple-gpus-with-custatevec-in-cuda-jl/113499)

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**Author:** [@tipfom](https://discourse.julialang.org/u/tipfom)\
**Replies:** 1\
**Last updated:** [April 25, 2024, 1:33pm UTC](https://discourse.julialang.org/t/multiple-gpus-with-custatevec-in-cuda-jl/113499 "2024-04-25T13:33:39Z")

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Hello, I’m trying to use multiple GPUs for computations involving CuStateVec from the CUDA.jl implementation, specifically the function swapIndexBitsMultiDevice!. However, this function always throws the error Argume…

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## [Gauss quadrature in 3D with change of variables](https://discourse.julialang.org/t/gauss-quadrature-in-3d-with-change-of-variables/113486)

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**Author:** [@Lisette\_de\_Bruin](https://discourse.julialang.org/u/Lisette_de_Bruin)\
**Replies:** 1\
**Last updated:** [April 25, 2024, 12:45pm UTC](https://discourse.julialang.org/t/gauss-quadrature-in-3d-with-change-of-variables/113486 "2024-04-25T12:45:43Z")

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Dear all, I want to solve an intgeral of the following form \\int\_0^1\\int\_x^1(x+y) dydx using a self implemented Gauss quadrature. The integral boundaries must be changed to \[-1,1\], which is done in the following way: …

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## [Problem in solve() DifferentialEquations. None algorithm define](https://discourse.julialang.org/t/problem-in-solve-differentialequations-none-algorithm-define/113342)

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**Author:** [@Marta\_Pardo\_Araujo](https://discourse.julialang.org/u/Marta_Pardo_Araujo)\
**Replies:** 11\
**Last updated:** [April 25, 2024, 11:26am UTC](https://discourse.julialang.org/t/problem-in-solve-differentialequations-none-algorithm-define/113342 "2024-04-25T11:26:42Z")

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Hi, I am new to Julia. I am trying to integrate an ODE. It works in my colleagues PC but not in mine. It looks like the package has not been loaded but I did it at the beginning of the script. I have tried with many sol…

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## [How to disable panning/dragging in Observables in GLMakie?](https://discourse.julialang.org/t/how-to-disable-panning-dragging-in-observables-in-glmakie/113466)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 2\
**Last updated:** [April 25, 2024, 8:45am UTC](https://discourse.julialang.org/t/how-to-disable-panning-dragging-in-observables-in-glmakie/113466 "2024-04-25T08:45:19Z")

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How to disable panning/dragging in Observables in GLMakie? I just want to click on scatterplot, not suddenly fall into constant zooming: Current code for mouse click control is simple: on(events(f).mousebutton, pr…

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## [ERROR: LoadError: MethodError: no method matching \_init\_identity\_matrix(::ComponentVector{Float32, Vector{Float32}, Tuple{Axis{…}}}, ::Float64)](https://discourse.julialang.org/t/error-loaderror-methoderror-no-method-matching-init-identity-matrix-componentvector-float32-vector-float32-tuple-axis-float64/112211)

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**Author:** [@KianH](https://discourse.julialang.org/u/KianH)\
**Replies:** 8\
**Last updated:** [April 25, 2024, 5:43am UTC](https://discourse.julialang.org/t/error-loaderror-methoderror-no-method-matching-init-identity-matrix-componentvector-float32-vector-float32-tuple-axis-float64/112211 "2024-04-25T05:43:04Z")

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Hi, When using BFGS from Optim.jl I occasionally get the following error message: ERROR: LoadError: MethodError: no method matching \_init\_identity\_matrix(::ComponentVector{Float32, Vector{Float32}, Tuple{Axis{…}}}, ::F…

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## [Second order polynomial fit in Makie.jl?](https://discourse.julialang.org/t/second-order-polynomial-fit-in-makie-jl/113413)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 2\
**Last updated:** [April 25, 2024, 4:36am UTC](https://discourse.julialang.org/t/second-order-polynomial-fit-in-makie-jl/113413 "2024-04-25T04:36:44Z")

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Is there a way to get the Polynomial. jl operation fit() to work in Makie.jl? I’ve tried to use the Makie.convert\_argument() and other iterations of it, but, maybe I’m using it incorrectly? Here is where I left it at …

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## [Turing Mixture Models with Dirichlet weightings](https://discourse.julialang.org/t/turing-mixture-models-with-dirichlet-weightings/112910)

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**Author:** [@Sam\_P](https://discourse.julialang.org/u/Sam_P)\
**Replies:** 8\
**Last updated:** [April 25, 2024, 12:47am UTC](https://discourse.julialang.org/t/turing-mixture-models-with-dirichlet-weightings/112910 "2024-04-25T00:47:03Z")

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Hi all - I’ve been trying to use the MixtureModel in Turing to sample from a multi-modal dataset, and generating the probability for each mode using the Dirichlet distributions. Yet somehow I’ve been getting an BoundsErr…

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## [Weird empty sum behavior in JuMP](https://discourse.julialang.org/t/weird-empty-sum-behavior-in-jump/113386)

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**Author:** [@KSepetanc](https://discourse.julialang.org/u/KSepetanc)\
**Replies:** 3\
**Last updated:** [April 24, 2024, 9:36pm UTC](https://discourse.julialang.org/t/weird-empty-sum-behavior-in-jump/113386 "2024-04-24T21:36:57Z")

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I am coding basic AC OPF model. The following sum results in an error: -(Vd\[n\]^2+Vq\[n\]^2)\*sum(gs\[sh\] for sh in bus\_shunts\[n\]) LoadError: MethodError: no method matching zero(::Type{MutableArithmetics.Zero}) Closest ca…

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## [Request help solving a Mathematical Programming with Equilibrium Constraints problem in JuMP?](https://discourse.julialang.org/t/request-help-solving-a-mathematical-programming-with-equilibrium-constraints-problem-in-jump/41802)

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**Author:** [@jack\_rabbit](https://discourse.julialang.org/u/jack_rabbit)\
**Replies:** 10\
**Last updated:** [April 24, 2024, 7:58pm UTC](https://discourse.julialang.org/t/request-help-solving-a-mathematical-programming-with-equilibrium-constraints-problem-in-jump/41802 "2024-04-24T19:58:36Z")

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Hi, I am pretty new to both Julia and JuMP. Please feel free to point out any aspects that I didn’t understand well. I am trying to solve a Mathematical Programming with Equilibrium Constraints (MPEC) problem using the…

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## [How to get a coordinates of the square in a heatmap using Observables?](https://discourse.julialang.org/t/how-to-get-a-coordinates-of-the-square-in-a-heatmap-using-observables/112573)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 4\
**Last updated:** [April 24, 2024, 4:05pm UTC](https://discourse.julialang.org/t/how-to-get-a-coordinates-of-the-square-in-a-heatmap-using-observables/112573 "2024-04-24T16:05:49Z")

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I have an image (or heatmap) and I want to be able to click and find x and y indexes of clicked area using Observables. How could it be possible?

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## [Adding external parameters to neural network](https://discourse.julialang.org/t/adding-external-parameters-to-neural-network/112968)

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**Author:** [@KianH](https://discourse.julialang.org/u/KianH)\
**Replies:** 5\
**Last updated:** [April 24, 2024, 3:03pm UTC](https://discourse.julialang.org/t/adding-external-parameters-to-neural-network/112968 "2024-04-24T15:03:41Z")

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Is there any way in Lux.jl or Flux.jl to create a function for a UDE and add some parameter, for instance the parameter c in the function rhs!(...) to a neural network so that the parameter c is also estimated through th…

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## [Makie fonts not always behaving as expected - Arial Bold and Symbol fonts](https://discourse.julialang.org/t/makie-fonts-not-always-behaving-as-expected-arial-bold-and-symbol-fonts/113450)

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**Author:** [@p\_f](https://discourse.julialang.org/u/p_f)\
**Replies:** 2\
**Last updated:** [April 24, 2024, 2:42pm UTC](https://discourse.julialang.org/t/makie-fonts-not-always-behaving-as-expected-arial-bold-and-symbol-fonts/113450 "2024-04-24T14:42:28Z")

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This is an extremely minor inconvinience, so if there is no fix it doesn’t really matter, but if there is a simple fix / I’m being dumb I’d like to know I can’t get Arial Bold to work, only Arial Rounded MT Bold julia\>…

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## [Drawing 3d polygons in Makie](https://discourse.julialang.org/t/drawing-3d-polygons-in-makie/65466)

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**Author:** [@t-bltg](https://discourse.julialang.org/u/t-bltg)\
**Replies:** 11\
**Last updated:** [April 24, 2024, 2:26pm UTC](https://discourse.julialang.org/t/drawing-3d-polygons-in-makie/65466 "2024-04-24T14:26:55Z")

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I’m trying to draw 3D polygons, but the only working way I found is cumbersome: is there some simple command I missed e.g. poly(X, Y, Z, color=C) that will allow me to plot 3D polygons in Makie ? using GLMakie # cols =…

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