# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=134

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**Page:** 135

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## [Long NLP evaluation time in Ipopt](https://discourse.julialang.org/t/long-nlp-evaluation-time-in-ipopt/109436)

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**Author:** [@tso-martin](https://discourse.julialang.org/u/tso-martin)\
**Replies:** 6\
**Last updated:** [February 14, 2024, 6:56am UTC](https://discourse.julialang.org/t/long-nlp-evaluation-time-in-ipopt/109436 "2024-02-14T06:56:32Z")

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Dear all, I encounter long evaluation times and slow convergence in an AC security constraint optimal power flow (SCOPF) optimization. The problem is modelled with PowerModels and JuMP. The NLP evaluation time is higher…

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## [Adding complementarity constraints](https://discourse.julialang.org/t/adding-complementarity-constraints/110132)

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**Author:** [@anand.kumar](https://discourse.julialang.org/u/anand.kumar)\
**Replies:** 4\
**Last updated:** [February 14, 2024, 4:39am UTC](https://discourse.julialang.org/t/adding-complementarity-constraints/110132 "2024-02-14T04:39:08Z")

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I’m new to both AMPL and JuMP. I’m trying to translate constraints below to jump but don’t understand how to do it. compl\_1{k in K}: 0 \<= ll\[1,k\] complements y\[1,k\] - x\[1\] \<= 0; compl\_2{k in K}: 0 \<= ll\[2,k\] comple…

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## [Dynamically Naming Expressions and Constraints in JuMP](https://discourse.julialang.org/t/dynamically-naming-expressions-and-constraints-in-jump/110181)

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**Author:** [@Lemma](https://discourse.julialang.org/u/Lemma)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 11:48pm UTC](https://discourse.julialang.org/t/dynamically-naming-expressions-and-constraints-in-jump/110181 "2024-02-13T23:48:43Z")

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In JuMP, it appears that expressions, constraints, and variables cannot be dynamically named using string interpolation (i.e., the $ symbol) directly within the identifiers of the @variable or @expression macros. Given t…

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## [Issue with the Metropolis adjusted Langevin sampler from AdvancedMH.jl](https://discourse.julialang.org/t/issue-with-the-metropolis-adjusted-langevin-sampler-from-advancedmh-jl/110155)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 10:13pm UTC](https://discourse.julialang.org/t/issue-with-the-metropolis-adjusted-langevin-sampler-from-advancedmh-jl/110155 "2024-02-13T22:13:39Z")

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I am trying to use a Metropolis adjusted Langevin sampler, from AdvancedMH.MALA. I did a simple test to see if things are working correctly, which is to sample from a multivariate normal distribution. Here is the code: i…

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## [Extracting projection from grib files](https://discourse.julialang.org/t/extracting-projection-from-grib-files/109818)

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**Author:** [@johnbb](https://discourse.julialang.org/u/johnbb)\
**Replies:** 4\
**Last updated:** [February 13, 2024, 8:01pm UTC](https://discourse.julialang.org/t/extracting-projection-from-grib-files/109818 "2024-02-13T20:01:09Z")

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Any recommendation on how to get the projection from grib files and to robustly create a proj string?

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## [Extracting numerical results from hamiltonian using Quantica](https://discourse.julialang.org/t/extracting-numerical-results-from-hamiltonian-using-quantica/107809)

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**Author:** [@alex123](https://discourse.julialang.org/u/alex123)\
**Replies:** 7\
**Last updated:** [February 13, 2024, 7:10pm UTC](https://discourse.julialang.org/t/extracting-numerical-results-from-hamiltonian-using-quantica/107809 "2024-02-13T19:10:29Z")

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Hi, I am using Quantica for finding the band structure of twisted bilayer graphene. Here is the part of my code that finds the hamiltonian: b = hamiltonian(tbg, model) |\> bands(subdiv((0, 2, 3, 4), 20); mapping=(0, 2,…

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## [Using Layout properly for Multiple plots in same box](https://discourse.julialang.org/t/using-layout-properly-for-multiple-plots-in-same-box/109241)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 3\
**Last updated:** [February 13, 2024, 5:43pm UTC](https://discourse.julialang.org/t/using-layout-properly-for-multiple-plots-in-same-box/109241 "2024-02-13T17:43:59Z")

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Hi all, I’m trying to get 2 plots (one on top of the other) in the same box, using the layout command, but I can’t seem to get the syntax right without errors. Julia’s document lists some examples using random numbers, …

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## [Failed to profile CUDA.jl with Nsight Systems 2024.1.1](https://discourse.julialang.org/t/failed-to-profile-cuda-jl-with-nsight-systems-2024-1-1/110051)

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**Author:** [@yuwenchen95](https://discourse.julialang.org/u/yuwenchen95)\
**Replies:** 4\
**Last updated:** [February 13, 2024, 11:19am UTC](https://discourse.julialang.org/t/failed-to-profile-cuda-jl-with-nsight-systems-2024-1-1/110051 "2024-02-13T11:19:54Z")

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I am following the doc to learn profiling GPU in Julia. When I followed $ nsys launch julia It started a Julia terminal but then failed when I run using CUDA and return errors: Please submit a bug report with steps …

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## [LibHealpix.jl v0.2.1](https://discourse.julialang.org/t/libhealpix-jl-v0-2-1/5062)

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**Author:** [@Michael\_Eastwood](https://discourse.julialang.org/u/Michael_Eastwood)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 5:16am UTC](https://discourse.julialang.org/t/libhealpix-jl-v0-2-1/5062 "2024-02-13T05:16:55Z")

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Given the rather large discussion thread about the need for an astro/space topic, I figured I might as well get the ball rolling. I have recently put a lot of effort into revamping and modernizing my LibHealpix.jl packa…

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## [JuMP: Behaviour of value for infeasible models](https://discourse.julialang.org/t/jump-behaviour-of-value-for-infeasible-models/109662)

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**Author:** [@samysweb](https://discourse.julialang.org/u/samysweb)\
**Replies:** 10\
**Last updated:** [February 13, 2024, 2:18am UTC](https://discourse.julialang.org/t/jump-behaviour-of-value-for-infeasible-models/109662 "2024-02-13T02:18:11Z")

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Hello everyone, I stumbled on a potential bug in JuMP and its dependencies, however, I wanted to ask this question here first as I am unsure whether this intended behavior and (if not) on which library level this should…

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## [Modifying a thread-local vector within CUDA Dynamic Parallelism](https://discourse.julialang.org/t/modifying-a-thread-local-vector-within-cuda-dynamic-parallelism/110110)

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**Author:** [@luciano-drozda](https://discourse.julialang.org/u/luciano-drozda)\
**Replies:** 2\
**Last updated:** [February 13, 2024, 1:19am UTC](https://discourse.julialang.org/t/modifying-a-thread-local-vector-within-cuda-dynamic-parallelism/110110 "2024-02-13T01:19:40Z")

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Hi! I’d like to modify an MVector in the context of CUDA Dynamic Parallelism. Here goes a minimal example: using CUDA, StaticArrays function outer!() v = MVector{1, Float32}(undef) @cuda dynamic = true inner!(v…

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## [JuMP / CPLEX: solution\_summary() seemingly returns something wrong](https://discourse.julialang.org/t/jump-cplex-solution-summary-seemingly-returns-something-wrong/110102)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 2\
**Last updated:** [February 12, 2024, 6:06pm UTC](https://discourse.julialang.org/t/jump-cplex-solution-summary-seemingly-returns-something-wrong/110102 "2024-02-12T18:06:44Z")

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I am trying to do some copositivity detection using a MILP with which I find an optimal solution as expected. However, solution\_summary() says that no solution exists. Here is an MWE: using JuMP using CPLEX function my…

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## [Error with couenne](https://discourse.julialang.org/t/error-with-couenne/110046)

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**Author:** [@medardo](https://discourse.julialang.org/u/medardo)\
**Replies:** 6\
**Last updated:** [February 12, 2024, 5:44pm UTC](https://discourse.julialang.org/t/error-with-couenne/110046 "2024-02-12T17:44:46Z")

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Hi, please help me. I can’t see the problem. I am using this code: using JuMP, AmplNLWriter, Couenne\_jll function run() model = Model(() → AmplNLWriter.Optimizer(Couenne\_jll.amplexe)) @variable(model, x) @variable(m…

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## [Copying a Model?](https://discourse.julialang.org/t/copying-a-model/71246)

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**Author:** [@chelseas](https://discourse.julialang.org/u/chelseas)\
**Replies:** 5\
**Last updated:** [February 12, 2024, 3:34pm UTC](https://discourse.julialang.org/t/copying-a-model/71246 "2024-02-12T15:34:05Z")

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Hi, I was wondering if there has been progress on the front of being able to copy/deepcopy a model in JuMP? Currently what I do is re-encode everything into the model but the encoding process is rather long and I would …

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## [Speeding up gradient of logpdf](https://discourse.julialang.org/t/speeding-up-gradient-of-logpdf/109708)

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**Author:** [@bertschi](https://discourse.julialang.org/u/bertschi)\
**Replies:** 19\
**Last updated:** [February 12, 2024, 3:08pm UTC](https://discourse.julialang.org/t/speeding-up-gradient-of-logpdf/109708 "2024-02-12T15:08:06Z")

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Somehow, I seem to be unable to speed up gradient calculations of a simple logpdf. As a minimal working example, consider the following computation: using Distributions import AbstractDifferentiation as AD import Forwar…

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## [Gradient of ODESystem containing a loop](https://discourse.julialang.org/t/gradient-of-odesystem-containing-a-loop/110103)

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**Author:** [@Kieran\_Marray](https://discourse.julialang.org/u/Kieran_Marray)\
**Replies:** 2\
**Last updated:** [February 12, 2024, 2:38pm UTC](https://discourse.julialang.org/t/gradient-of-odesystem-containing-a-loop/110103 "2024-02-12T14:38:32Z")

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Hi! I am trying to take the gradient of an ODESystem containing a loop using either Zygote or ForwardDiff. Both seem to fail when I do so. Here is a minimal working example (taken from a previous JuliaForum post) using…

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## [CUDA + StaticArrays weird dynamic function invocation](https://discourse.julialang.org/t/cuda-staticarrays-weird-dynamic-function-invocation/109881)

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**Author:** [@trahflow](https://discourse.julialang.org/u/trahflow)\
**Replies:** 2\
**Last updated:** [February 12, 2024, 12:07pm UTC](https://discourse.julialang.org/t/cuda-staticarrays-weird-dynamic-function-invocation/109881 "2024-02-12T12:07:29Z")

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Hi, I have a weird issue that is somewhat related to this thread. When using StaticArrays within a CUDA kernel, it seems to be necessary to add @inbounds before converting arrays/views to static arrays, otherwise this …

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## [Memory management in CPLEX.jl](https://discourse.julialang.org/t/memory-management-in-cplex-jl/109704)

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**Author:** [@Matheus\_Diogenes\_And](https://discourse.julialang.org/u/Matheus_Diogenes_And)\
**Replies:** 9\
**Last updated:** [February 11, 2024, 11:28pm UTC](https://discourse.julialang.org/t/memory-management-in-cplex-jl/109704 "2024-02-11T23:28:12Z")

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Hello. I am investigating a behavior related to the execution of CPLEX.jl. So, let’s consider the following environment: Linux pop-os 6.4.6-76060406-generic; And Julia version 1.8.4. And the following commands: juli…

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## [Makie diffeq recipes](https://discourse.julialang.org/t/makie-diffeq-recipes/110078)

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**Author:** [@henry2004y](https://discourse.julialang.org/u/henry2004y)\
**Replies:** 0\
**Last updated:** [February 11, 2024, 7:57pm UTC](https://discourse.julialang.org/t/makie-diffeq-recipes/110078 "2024-02-11T19:57:57Z")

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Recently a new Makie recipe for DifferentialEquations was added using PlotSpec. However, I noticed that at least two things are not working: Line attributes are ignored. For example, linestyle and linewidth are always …

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## [Ongoing maintenance and support for DelaunayTriangulation.jl](https://discourse.julialang.org/t/ongoing-maintenance-and-support-for-delaunaytriangulation-jl/109635)

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**Author:** [@mbauman](https://discourse.julialang.org/u/mbauman)\
**Replies:** 11\
**Last updated:** [February 11, 2024, 3:26pm UTC](https://discourse.julialang.org/t/ongoing-maintenance-and-support-for-delaunaytriangulation-jl/109635 "2024-02-11T15:26:14Z")

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In the what aspects is Julia weak in thread, the topic of ongoing support for DelaunayTriangulation.jl was raised and prompted a good amount of subsequent discussion: We will probably pull this into SciML. I still need…

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## [CPLEX: CPXwritemipstarts without optimize!](https://discourse.julialang.org/t/cplex-cpxwritemipstarts-without-optimize/109973)

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**Author:** [@remi-garcia](https://discourse.julialang.org/u/remi-garcia)\
**Replies:** 5\
**Last updated:** [February 11, 2024, 7:42am UTC](https://discourse.julialang.org/t/cplex-cpxwritemipstarts-without-optimize/109973 "2024-02-11T07:42:23Z")

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Hi, I would like to be able to save a model and its warm start as the solver got them when calling optimize!. using JuMP using CPLEX m = Model(CPLEX.Optimizer); direct\_m = direct\_model(CPLEX.Optimizer()); @variable(m, …

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## [JuMP new nonlinear interface: adding constraint programatically](https://discourse.julialang.org/t/jump-new-nonlinear-interface-adding-constraint-programatically/110041)

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**Author:** [@franckgaga](https://discourse.julialang.org/u/franckgaga)\
**Replies:** 4\
**Last updated:** [February 10, 2024, 8:41pm UTC](https://discourse.julialang.org/t/jump-new-nonlinear-interface-adding-constraint-programatically/110041 "2024-02-10T20:41:15Z")

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ModelPredictiveControl.jl is still using the legacy syntax for NLP, but I’m starting the migration right now. The nonlinear inequality constraints are currently added programmatically with (simplified for the purpose of …

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## [Implementing semi-implicit Fourier spectral method](https://discourse.julialang.org/t/implementing-semi-implicit-fourier-spectral-method/109686)

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**Author:** [@yhchang96](https://discourse.julialang.org/u/yhchang96)\
**Replies:** 1\
**Last updated:** [February 10, 2024, 7:40pm UTC](https://discourse.julialang.org/t/implementing-semi-implicit-fourier-spectral-method/109686 "2024-02-10T19:40:44Z")

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I’m trying to implement the semi-implicit Fourier spectral method described here. It is basically a fourth-order phase-field equation, the linear fourth order operator is treated implicitly and the nonlinear operator ter…

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## [Solve y'=y with neuralode](https://discourse.julialang.org/t/solve-y-y-with-neuralode/109993)

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**Author:** [@ATR](https://discourse.julialang.org/u/ATR)\
**Replies:** 6\
**Last updated:** [February 10, 2024, 6:33pm UTC](https://discourse.julialang.org/t/solve-y-y-with-neuralode/109993 "2024-02-10T18:33:38Z")

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Dear all, I am beginner in this topic and trying to solve simple y’=y (analytical solution: exp(t)) with y0=0 by modifying code on Neural Ordinary Differential Equations · DiffEqFlux.jl (sciml.ai), my code until now: be…

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## [I am unable to run a simple distributed.jl code on my slurm cluster](https://discourse.julialang.org/t/i-am-unable-to-run-a-simple-distributed-jl-code-on-my-slurm-cluster/109892)

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**Author:** [@Shashank](https://discourse.julialang.org/u/Shashank)\
**Replies:** 11\
**Last updated:** [February 10, 2024, 4:30pm UTC](https://discourse.julialang.org/t/i-am-unable-to-run-a-simple-distributed-jl-code-on-my-slurm-cluster/109892 "2024-02-10T16:30:36Z")

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I am trying to run a simple file that is pasted below: using Distributed addprocs(4) println("Number of processes: ", nprocs()) println("Number of workers: ", nworkers()) @sync @distributed for i in 1:4 sleep(1) …

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## [Dynamic Constraints in JuMP](https://discourse.julialang.org/t/dynamic-constraints-in-jump/110012)

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**Author:** [@Lemma](https://discourse.julialang.org/u/Lemma)\
**Replies:** 1\
**Last updated:** [February 10, 2024, 6:28am UTC](https://discourse.julialang.org/t/dynamic-constraints-in-jump/110012 "2024-02-10T06:28:30Z")

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I am working on an iterative solution for a multi-period model. The approach involves solving the model for the initial time period (t=1), then using the outcome (specifically, the values of variable z) as parameters for…

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## [Build\_function: stack overflow in type inference](https://discourse.julialang.org/t/build-function-stack-overflow-in-type-inference/109971)

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**Author:** [@Johan-Gronqvist](https://discourse.julialang.org/u/Johan-Gronqvist)\
**Replies:** 4\
**Last updated:** [February 9, 2024, 9:23pm UTC](https://discourse.julialang.org/t/build-function-stack-overflow-in-type-inference/109971 "2024-02-09T21:23:23Z")

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I am trying to use Symbolics.build\_function to generate JuMP.AffExpr expressions from symbolic expressions. I see an error message Internal error: stack overflow in type inference of (::RuntimeGeneratedFunctions.Runtim…

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## [Is using parallel computing to create JuMP constraints possible and useful?](https://discourse.julialang.org/t/is-using-parallel-computing-to-create-jump-constraints-possible-and-useful/109992)

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**Author:** [@K5Julien](https://discourse.julialang.org/u/K5Julien)\
**Replies:** 1\
**Last updated:** [February 9, 2024, 8:17pm UTC](https://discourse.julialang.org/t/is-using-parallel-computing-to-create-jump-constraints-possible-and-useful/109992 "2024-02-09T20:17:00Z")

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I was wondering if there is any advantage to generate JuMP constraints with @threads regarding the CPU times. Threads.@threads for c in set\_curtailments @constraint(model, sum(x\[:, c\]) .\<= y\[c\] \* nrow(data\_s…

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## [Using Zygote with ComponentArrays](https://discourse.julialang.org/t/using-zygote-with-componentarrays/109715)

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**Author:** [@ablaom](https://discourse.julialang.org/u/ablaom)\
**Replies:** 1\
**Last updated:** [February 9, 2024, 8:14pm UTC](https://discourse.julialang.org/t/using-zygote-with-componentarrays/109715 "2024-02-09T20:14:04Z")

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I am computing gradients of functions using Zygote. The argument of my function is a ComponentArray, because my functions depend on DifferentialEquation.jl solvers using adjoint method. I have been naively assuming Zygot…

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## [How to convert 3D mesh to voxelated array image?](https://discourse.julialang.org/t/how-to-convert-3d-mesh-to-voxelated-array-image/21777)

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**Author:** [@jonalm](https://discourse.julialang.org/u/jonalm)\
**Replies:** 8\
**Last updated:** [February 9, 2024, 5:40pm UTC](https://discourse.julialang.org/t/how-to-convert-3d-mesh-to-voxelated-array-image/21777 "2024-02-09T17:40:02Z")

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Dear community. I’m looking for some image related functionality which may already be implemented in Julia. I haven’t managed to find them, but that may be because I do not know what to search for (I’ve limited experienc…

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