# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=135

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**Page:** 136

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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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## [Finding the rank of an augmented matrix](https://discourse.julialang.org/t/finding-the-rank-of-an-augmented-matrix/109988)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 2\
**Last updated:** [February 9, 2024, 4:09pm UTC](https://discourse.julialang.org/t/finding-the-rank-of-an-augmented-matrix/109988 "2024-02-09T16:09:29Z")

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I want to determine if a system of equations has no solutions. According to Wikipedia a system of equations has no solutions if its augmented matrix has higher rank than its coefficient matrix. In Julia the natural way…

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## [Columns and Constraints generation](https://discourse.julialang.org/t/columns-and-constraints-generation/103813)

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**Author:** [@Salma](https://discourse.julialang.org/u/Salma)\
**Replies:** 13\
**Last updated:** [February 9, 2024, 1:16pm UTC](https://discourse.julialang.org/t/columns-and-constraints-generation/103813 "2024-02-09T13:16:40Z")

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Hello, I’m looking to implement two-stage robust optimization using column and constraint generation. I’ve encountered an issue within while loop related to the optimize!() function when trying to implement the algorithm…

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## [Nan values when adding constraint to inversion](https://discourse.julialang.org/t/nan-values-when-adding-constraint-to-inversion/109922)

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**Author:** [@vivekag7](https://discourse.julialang.org/u/vivekag7)\
**Replies:** 2\
**Last updated:** [February 8, 2024, 11:20pm UTC](https://discourse.julialang.org/t/nan-values-when-adding-constraint-to-inversion/109922 "2024-02-08T23:20:29Z")

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Hi Julia community, I have been trying to add a constraint to my inversion process: using Optimization, Optim, OptimizationOptimJL # Objective function function objfun(x, simulation, realsol) simulation.mo…

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