# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=118

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**Page:** 119

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## [Addprocs: specify both multithreading and active environment](https://discourse.julialang.org/t/addprocs-specify-both-multithreading-and-active-environment/80427)

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**Author:** [@Gregstrq](https://discourse.julialang.org/u/Gregstrq)\
**Replies:** 2\
**Last updated:** [April 16, 2024, 5:11pm UTC](https://discourse.julialang.org/t/addprocs-specify-both-multithreading-and-active-environment/80427 "2024-04-16T17:11:02Z")

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Let’s say I want to add a process with 8 threads. This is easy: using Distributed addprocs(1, exeflags="-t 8") One can check that @fetchfrom 2 Threads.nthreads() returns 8 as expected. But, if I try to specify the env…

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## [GeometricMachineLearning.jl: Looking for a direct contact opportunity with persons involved](https://discourse.julialang.org/t/geometricmachinelearning-jl-looking-for-a-direct-contact-opportunity-with-persons-involved/113025)

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**Author:** [@j\_u](https://discourse.julialang.org/u/j_u)\
**Replies:** 0\
**Last updated:** [April 16, 2024, 3:42pm UTC](https://discourse.julialang.org/t/geometricmachinelearning-jl-looking-for-a-direct-contact-opportunity-with-persons-involved/113025 "2024-04-16T15:42:48Z")

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Hi, I am looking for a direct contact opportunity with persons involved in GeometricMachineLearning.jl. I joined Julia Community a few years ago thanks to a hobby project of mine about "Neural network analysis of uncerta…

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## [How to specify xticks with min, max an arbitrary number?](https://discourse.julialang.org/t/how-to-specify-xticks-with-min-max-an-arbitrary-number/113021)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 0\
**Last updated:** [April 16, 2024, 3:03pm UTC](https://discourse.julialang.org/t/how-to-specify-xticks-with-min-max-an-arbitrary-number/113021 "2024-04-16T15:03:13Z")

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I want to specify ax.xticks with min of xvalue, 0.0, mean of xvalue, max of xvalue. How can I implement that?

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## [GPU memory usage increasing on each epoch (Flux)](https://discourse.julialang.org/t/gpu-memory-usage-increasing-on-each-epoch-flux/112942)

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**Author:** [@evanfields](https://discourse.julialang.org/u/evanfields)\
**Replies:** 5\
**Last updated:** [April 16, 2024, 2:16pm UTC](https://discourse.julialang.org/t/gpu-memory-usage-increasing-on-each-epoch-flux/112942 "2024-04-16T14:16:01Z")

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I’m catching up on the last few years of Flux progress (thanks, Flux devs!) by training some toy models, and am surprised to find that GPU memory usage is increasing on each training epoch, even when all training data is…

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## [Cubature of Singular Integrand](https://discourse.julialang.org/t/cubature-of-singular-integrand/113003)

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**Author:** [@Domenico\_Lahaye](https://discourse.julialang.org/u/Domenico_Lahaye)\
**Replies:** 3\
**Last updated:** [April 16, 2024, 1:33pm UTC](https://discourse.julialang.org/t/cubature-of-singular-integrand/113003 "2024-04-16T13:33:06Z")

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?quadgk provides as output !!! note Only one-dimensional integrals are provided by this function. For multi-dimensional integration (cubature), there are many different algorithms (often much better than simple nested 1…

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## [Question regarding numerical stability among Julia versions](https://discourse.julialang.org/t/question-regarding-numerical-stability-among-julia-versions/112741)

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**Author:** [@CodeLenz](https://discourse.julialang.org/u/CodeLenz)\
**Replies:** 16\
**Last updated:** [April 16, 2024, 12:54pm UTC](https://discourse.julialang.org/t/question-regarding-numerical-stability-among-julia-versions/112741 "2024-04-16T12:54:05Z")

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Dear Julians. I was testing the following code (M,C and K are sparse, symmetric and positive definite matrices) Julia\> M,C,K=THS(); julia\> cholM=cholesky(M); julia\> Cb = cholM\\C; julia\> Kb = cholM\\K; julia\> F = 0.…

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## [Solving a nonlinear equation using NonlinearSolve.jl with AutoFiniteDiff() yields errors about dual number](https://discourse.julialang.org/t/solving-a-nonlinear-equation-using-nonlinearsolve-jl-with-autofinitediff-yields-errors-about-dual-number/112988)

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**Author:** [@LINGXIAO\_QIN](https://discourse.julialang.org/u/LINGXIAO_QIN)\
**Replies:** 2\
**Last updated:** [April 16, 2024, 12:13pm UTC](https://discourse.julialang.org/t/solving-a-nonlinear-equation-using-nonlinearsolve-jl-with-autofinitediff-yields-errors-about-dual-number/112988 "2024-04-16T12:13:18Z")

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I am trying to solve a nonlinear equation, which is constructed using the thermophysical properties of fluids (via CoolProp package). An MWE is shown below. using NonlinearSolve, CoolProp function myfun\_P\_MWE(p, (T, i…

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## [Speed up JuMP.jl Estimation When Jacobian and Hessian of Constraints are Sparse](https://discourse.julialang.org/t/speed-up-jump-jl-estimation-when-jacobian-and-hessian-of-constraints-are-sparse/112981)

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**Author:** [@Strange\_Xue](https://discourse.julialang.org/u/Strange_Xue)\
**Replies:** 6\
**Last updated:** [April 16, 2024, 11:08am UTC](https://discourse.julialang.org/t/speed-up-jump-jl-estimation-when-jacobian-and-hessian-of-constraints-are-sparse/112981 "2024-04-16T11:08:20Z")

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Hi guys, in last questions (link is shown below), I asked how to supply gradient of objective and jacobian of constraints in nonlinear optimization. But @odow told me I dont have to do that because JuMP.jl will automatic…

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## [NeuralODE with covariates](https://discourse.julialang.org/t/neuralode-with-covariates/112999)

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**Author:** [@elcup](https://discourse.julialang.org/u/elcup)\
**Replies:** 1\
**Last updated:** [April 16, 2024, 9:34am UTC](https://discourse.julialang.org/t/neuralode-with-covariates/112999 "2024-04-16T09:34:16Z")

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Hi. Am an quite new with Julia and I am stuck with something. Maybe you can help me (sorry if I am trying something stupid). I am working with Neural ODEs using DiffEqFlux. I want to model the differential equation with…

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## [Error when using MKLDirectSolver in SCS](https://discourse.julialang.org/t/error-when-using-mkldirectsolver-in-scs/112982)

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**Author:** [@charshaw](https://discourse.julialang.org/u/charshaw)\
**Replies:** 2\
**Last updated:** [April 15, 2024, 11:20pm UTC](https://discourse.julialang.org/t/error-when-using-mkldirectsolver-in-scs/112982 "2024-04-15T23:20:59Z")

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I am using JuMP and calling SCS as a solver. I want to use SCS.MKLDirectSolver, as discussed in an earlier thread. As discussed on the SCS.jl README page, this requires using the package SCS\_MKL\_jll. But, I’m getting an…

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## [JuMP.jl: Supplying gradient of objective and jacobian of constraints in Nonlinear Optimization](https://discourse.julialang.org/t/jump-jl-supplying-gradient-of-objective-and-jacobian-of-constraints-in-nonlinear-optimization/106940)

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**Author:** [@Strange\_Xue](https://discourse.julialang.org/u/Strange_Xue)\
**Replies:** 12\
**Last updated:** [April 15, 2024, 9:14pm UTC](https://discourse.julialang.org/t/jump-jl-supplying-gradient-of-objective-and-jacobian-of-constraints-in-nonlinear-optimization/106940 "2024-04-15T21:14:31Z")

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Hi, I am faced with a troublesome optimization problem. As shown below, the non-linear optimization problem is easy to model and solve via Ipopt with JuMP.jl as interface. However, the objective function and constraints…

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## [ForwardDiff.jacobian Method error](https://discourse.julialang.org/t/forwarddiff-jacobian-method-error/112979)

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**Author:** [@Domenico\_Lahaye](https://discourse.julialang.org/u/Domenico_Lahaye)\
**Replies:** 2\
**Last updated:** [April 15, 2024, 8:59pm UTC](https://discourse.julialang.org/t/forwarddiff-jacobian-method-error/112979 "2024-04-15T20:59:41Z")

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I get a method error with ForwardDiff.jacobian that I fails to understand. Below a MWE. function fooworks(cvec,xmesh) residual = cvec return residual end function foofails(cvec,xmesh) residual = zeros(len…

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## [Mesh is displayed properly on CairoMakie, but not in GLMakie](https://discourse.julialang.org/t/mesh-is-displayed-properly-on-cairomakie-but-not-in-glmakie/112977)

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**Author:** [@marcsgil](https://discourse.julialang.org/u/marcsgil)\
**Replies:** 0\
**Last updated:** [April 15, 2024, 7:58pm UTC](https://discourse.julialang.org/t/mesh-is-displayed-properly-on-cairomakie-but-not-in-glmakie/112977 "2024-04-15T19:58:24Z")

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Hello! I’m running the following code snippet to produce a sphere: using GLMakie fig = Figure() ax = Axis3(fig\[1, 1\], aspect=:equal) mesh!(ax, Sphere(Point3f(0), 1), alpha=0.1) scatter!(ax,0,0,0, color=:red) fig wi…

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## [How to extract the upper/lower triangular matrix values except the diagonal?](https://discourse.julialang.org/t/how-to-extract-the-upper-lower-triangular-matrix-values-except-the-diagonal/112974)

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**Author:** [@Shayan](https://discourse.julialang.org/u/Shayan)\
**Replies:** 4\
**Last updated:** [April 15, 2024, 6:07pm UTC](https://discourse.julialang.org/t/how-to-extract-the-upper-lower-triangular-matrix-values-except-the-diagonal/112974 "2024-04-15T18:07:52Z")

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Consider the following matrix: julia\> c = rand(2, 2) 2×2 Matrix{Float64}: 0.0443768 0.515352 0.531426 0.967584 Expected output: 1-element Vector{Float64}: 0.531426 I can do: julia\> using LinearAlgebra: LowerTri…

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## [Outputting string columns using Avro.jl](https://discourse.julialang.org/t/outputting-string-columns-using-avro-jl/80112)

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**Author:** [@kobusherbst](https://discourse.julialang.org/u/kobusherbst)\
**Replies:** 5\
**Last updated:** [April 15, 2024, 5:13pm UTC](https://discourse.julialang.org/t/outputting-string-columns-using-avro-jl/80112 "2024-04-15T17:13:51Z")

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When I try to convert an Arrow file to Avro using this code: function t\_arrowtoavro(path, file) a = Arrow.Table(joinpath(path, "$(file).arrow")) |\> DataFrame println(Tables.schema(a)) Avro.writetable(joinpat…

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## [ODEProblem(....) vs NeuralODE(....) for neural ODEs](https://discourse.julialang.org/t/odeproblem-vs-neuralode-for-neural-odes/112670)

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**Author:** [@KianH](https://discourse.julialang.org/u/KianH)\
**Replies:** 14\
**Last updated:** [April 15, 2024, 2:16pm UTC](https://discourse.julialang.org/t/odeproblem-vs-neuralode-for-neural-odes/112670 "2024-04-15T14:16:22Z")

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Hello! I am wondering about the difference when using ODEProblem(....) from DifferentialEquations.jl and NeuralODE(....) from DiffEqFlux.jl in terms of time performance. Consider the code below, thus, definining the …

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## [Sundials KLU Linear solver](https://discourse.julialang.org/t/sundials-klu-linear-solver/112954)

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**Author:** [@jespfra](https://discourse.julialang.org/u/jespfra)\
**Replies:** 1\
**Last updated:** [April 15, 2024, 10:55am UTC](https://discourse.julialang.org/t/sundials-klu-linear-solver/112954 "2024-04-15T10:55:33Z")

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Hi everyone, I am trying to use the KLU method as linear solver for solving an ODE problem using Sundials. I have tried to apply it to the CVODE\_BDF solver for a simple problem, the rober equation. However, when I prov…

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## [Plot two legends (e.g. one for color and one for shape) with \`Plots.jl\`](https://discourse.julialang.org/t/plot-two-legends-e-g-one-for-color-and-one-for-shape-with-plots-jl/40746)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 5\
**Last updated:** [April 15, 2024, 7:04am UTC](https://discourse.julialang.org/t/plot-two-legends-e-g-one-for-color-and-one-for-shape-with-plots-jl/40746 "2024-04-15T07:04:01Z")

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How can I make a plot like this in Plots.jl (this was made with matplotlib): Basically four lines: plot( data1, color=c1, linestyle=s1) plot!(data2, color=c2, linestyle=s1) plot!(data3, color=c1, linestyle=s2) plot!(…

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## [Solving shifted linear system](https://discourse.julialang.org/t/solving-shifted-linear-system/111265)

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**Author:** [@rvaradhan](https://discourse.julialang.org/u/rvaradhan)\
**Replies:** 19\
**Last updated:** [April 15, 2024, 5:52am UTC](https://discourse.julialang.org/t/solving-shifted-linear-system/111265 "2024-04-15T05:52:22Z")

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I would like to solve a large shifted linear system: I have to solve (A + k^2 I)x = y, where A is symmetric PD, y is a vector, k is a scalar, and I is identity matrix. Matrix A is large O(10000 x 10000) but it is banded…

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## [Batched LU solves (or Factorizations) with Sparse Matrices](https://discourse.julialang.org/t/batched-lu-solves-or-factorizations-with-sparse-matrices/106019)

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**Author:** [@schev](https://discourse.julialang.org/u/schev)\
**Replies:** 6\
**Last updated:** [April 15, 2024, 5:37am UTC](https://discourse.julialang.org/t/batched-lu-solves-or-factorizations-with-sparse-matrices/106019 "2024-04-15T05:37:51Z")

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Let’s say I have a sparse set of matrices A1, A2, ... An, each of type CuSparseMatrixCSC{Float32, Int32} along with associated RHS vectors b1, b2, ... bn. Is there some watch to do a batch LU solve on the GPU with CUDA.j…

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## [Updating CUDA seems to have completely broken the package](https://discourse.julialang.org/t/updating-cuda-seems-to-have-completely-broken-the-package/110101)

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**Author:** [@Hareruya](https://discourse.julialang.org/u/Hareruya)\
**Replies:** 3\
**Last updated:** [April 14, 2024, 11:36pm UTC](https://discourse.julialang.org/t/updating-cuda-seems-to-have-completely-broken-the-package/110101 "2024-04-14T23:36:36Z")

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Salutations, I am currently a PhD student and defended my thesis last month. Most of my Master’s research and all of my PhD research were developed using julia. I decided to update julia and run my old code at which poi…

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## [Grouping by values in either of two columns](https://discourse.julialang.org/t/grouping-by-values-in-either-of-two-columns/112499)

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**Author:** [@KeepLearning](https://discourse.julialang.org/u/KeepLearning)\
**Replies:** 13\
**Last updated:** [April 14, 2024, 8:47am UTC](https://discourse.julialang.org/t/grouping-by-values-in-either-of-two-columns/112499 "2024-04-14T08:47:12Z")

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Hi, I wonder if there is an efficient way of doing the following in Julia DataFrames. Given a DataFrame df = DataFrame(col1 = \["a", "a", "b", "b", "c", "d"\], col2 = \["p", "q", "q", "r", "s", "t"\]) I wa…

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## [Optimization with LBFGS gives DimensionMismatch("dimensions must match")](https://discourse.julialang.org/t/optimization-with-lbfgs-gives-dimensionmismatch-dimensions-must-match/22167)

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**Author:** [@mzhenirovskyy](https://discourse.julialang.org/u/mzhenirovskyy)\
**Replies:** 9\
**Last updated:** [April 14, 2024, 7:39pm UTC](https://discourse.julialang.org/t/optimization-with-lbfgs-gives-dimensionmismatch-dimensions-must-match/22167 "2024-04-14T19:39:36Z")

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My objective function has to solve an ODE. When I use the gradient-free algorithm (e.g NelderMead) to do optimization, everything is OK. But with gradient-based (e.g. LBFGS) I get the error: DimensionMismatch(“dimension…

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## [Dynamical system of modelling two particle collisions](https://discourse.julialang.org/t/dynamical-system-of-modelling-two-particle-collisions/112922)

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**Author:** [@hisacro](https://discourse.julialang.org/u/hisacro)\
**Replies:** 4\
**Last updated:** [April 14, 2024, 5:40pm UTC](https://discourse.julialang.org/t/dynamical-system-of-modelling-two-particle-collisions/112922 "2024-04-14T17:40:05Z")

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Hello, I’m trying to model a system with collision dynamics. I’m well aware of Datseris’s DynamicalBillards, contrary to that what I’m studying is collision between 2 particles rather than the fixed geometry as in billa…

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## [Setting up multi-output Gaussian process with Surrogates.jl](https://discourse.julialang.org/t/setting-up-multi-output-gaussian-process-with-surrogates-jl/112881)

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**Author:** [@epi\_hannah](https://discourse.julialang.org/u/epi_hannah)\
**Replies:** 2\
**Last updated:** [April 14, 2024, 1:39pm UTC](https://discourse.julialang.org/t/setting-up-multi-output-gaussian-process-with-surrogates-jl/112881 "2024-04-14T13:39:51Z")

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Hi all, I am trying to use Surrogates to train a Gaussian process surrogate to a model with 2 different outputs (i.e., a multi-output model). According to the Surrogates documentation I can use custom kriging in Stheno…

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## [Using \`bboptimize\` with a function containing \`JuMP\` calls](https://discourse.julialang.org/t/using-bboptimize-with-a-function-containing-jump-calls/112846)

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**Author:** [@Rick](https://discourse.julialang.org/u/Rick)\
**Replies:** 2\
**Last updated:** [April 14, 2024, 6:52am UTC](https://discourse.julialang.org/t/using-bboptimize-with-a-function-containing-jump-calls/112846 "2024-04-14T06:52:53Z")

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Hi everyone, I am trying blackbox optimization with a function that contains JuMP functions. So, this is like a nested optimization where the “inner problem” is evaluated using JuMP functions and the “outer problem” is …

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## [Gtk stopped working on MacOS in March or April 2024](https://discourse.julialang.org/t/gtk-stopped-working-on-macos-in-march-or-april-2024/112904)

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**Author:** [@JeffFessler](https://discourse.julialang.org/u/JeffFessler)\
**Replies:** 2\
**Last updated:** [April 13, 2024, 4:38pm UTC](https://discourse.julialang.org/t/gtk-stopped-working-on-macos-in-march-or-april-2024/112904 "2024-04-13T16:38:41Z")

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Gtk stopped working for me on MacOS sometime this semester (I am teaching a music signal processing course using Julia with \>60 students). Here is a MWE of code that worked a month or so ago and now does not work on Mac…

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## [Optimization, from MATLAB to Julia](https://discourse.julialang.org/t/optimization-from-matlab-to-julia/111212)

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**Author:** [@cu2mauro](https://discourse.julialang.org/u/cu2mauro)\
**Replies:** 10\
**Last updated:** [April 13, 2024, 11:43am UTC](https://discourse.julialang.org/t/optimization-from-matlab-to-julia/111212 "2024-04-13T11:43:23Z")

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Hi there! I am fairly new to Julia, I was converted after seeing some awesome performance compared to MATLAB, which I currently use. I tried rewriting in Julia an optimization problem that I had in MATLAB, and everythin…

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## [How to avoid "Julia is not responding" when using a file dialog](https://discourse.julialang.org/t/how-to-avoid-julia-is-not-responding-when-using-a-file-dialog/112075)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 5\
**Last updated:** [March 25, 2024, 12:14pm UTC](https://discourse.julialang.org/t/how-to-avoid-julia-is-not-responding-when-using-a-file-dialog/112075 "2024-03-25T12:14:47Z")

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I have a GLMakie based GUI app and want to load a file using a native file dialog. This is my code: using GLMakie, NativeFileDialog fig = Figure(size=(200, 200), backgroundcolor=RGBf(0.7, 0.8, 1)) btn\_RUN = Button(fig…

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## [Problem with hover display in heatmap with plotlyjs backend](https://discourse.julialang.org/t/problem-with-hover-display-in-heatmap-with-plotlyjs-backend/107586)

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**Author:** [@adannenberg](https://discourse.julialang.org/u/adannenberg)\
**Replies:** 7\
**Last updated:** [April 13, 2024, 1:56am UTC](https://discourse.julialang.org/t/problem-with-hover-display-in-heatmap-with-plotlyjs-backend/107586 "2024-04-13T01:56:59Z")

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if i use the plotly backend to make a heatmap with a small number of categorical variables then everything is fine using Plots plotly() categories = string.(collect('a':'e')) n = length(categories) #5 heatmap(categorie…

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