# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=42

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**Page:** 43

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## [Eigen fails to find eigenvectors](https://discourse.julialang.org/t/eigen-fails-to-find-eigenvectors/129072)

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**Author:** [@martinkjlarsson](https://discourse.julialang.org/u/martinkjlarsson)\
**Replies:** 28\
**Last updated:** [May 20, 2025, 3:14pm UTC](https://discourse.julialang.org/t/eigen-fails-to-find-eigenvectors/129072 "2025-05-20T15:14:41Z")

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I am confused. I’m finding the eigenvalues and eigenvectors of a 3x3 matrix, but it seems like eigen does not find all the vectors correctly. julia\> using LinearAlgebra julia\> A = \[1 1 1; 1 1 1; -1 -1 -1\] 3×3 Matrix{In…

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## [Run only the algebraic part of the solver](https://discourse.julialang.org/t/run-only-the-algebraic-part-of-the-solver/128803)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 27\
**Last updated:** [May 20, 2025, 11:39am UTC](https://discourse.julialang.org/t/run-only-the-algebraic-part-of-the-solver/128803 "2025-05-20T11:39:55Z")

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I’m working with a DAE system in ModelingToolkit.jl, and I’d like to run only the algebraic part of the integrator-that is, solve the algebraic constraints for given differential states, without advancing the differentia…

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## [AdaptiveCpp integration?](https://discourse.julialang.org/t/adaptivecpp-integration/129070)

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**Author:** [@Oblomov](https://discourse.julialang.org/u/Oblomov)\
**Replies:** 9\
**Last updated:** [May 20, 2025, 10:34am UTC](https://discourse.julialang.org/t/adaptivecpp-integration/129070 "2025-05-20T10:34:47Z")

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Hi all, I’ve recently started looking at AdaptiveCpp for some of my C++ work, and‌ I’m starting to get a feeling that this would be an excellent fit for Julia’s GPGPU. For those who don’t know, AdaptiveCpp, formerly kn…

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## [Ragged Tensors with generic GPU code](https://discourse.julialang.org/t/ragged-tensors-with-generic-gpu-code/129134)

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**Author:** [@BSchilperoort](https://discourse.julialang.org/u/BSchilperoort)\
**Replies:** 2\
**Last updated:** [May 20, 2025, 10:24am UTC](https://discourse.julialang.org/t/ragged-tensors-with-generic-gpu-code/129134 "2025-05-20T10:24:50Z")

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I am working on porting (parts of) a hydrological model to GPU, to improve performance. This is largely going well because of the KernelAbstractions and AcceleratedKernels packages, which make it quite straightforward to…

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## [After trying to plot negative values using \`yaxis = :log10\`, all plots breaks down](https://discourse.julialang.org/t/after-trying-to-plot-negative-values-using-yaxis-log10-all-plots-breaks-down/129167)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 4\
**Last updated:** [May 20, 2025, 10:22am UTC](https://discourse.julialang.org/t/after-trying-to-plot-negative-values-using-yaxis-log10-all-plots-breaks-down/129167 "2025-05-20T10:22:19Z")

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Basically, I (by misstake) tried to plot something where the values go negative and I asked for a log scaled y axis. Ofcourse this failed. However, it also meant that all other plots failed. It would be good if this cou…

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## [Matrix inverse as objective](https://discourse.julialang.org/t/matrix-inverse-as-objective/129162)

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**Author:** [@Rick](https://discourse.julialang.org/u/Rick)\
**Replies:** 2\
**Last updated:** [May 20, 2025, 5:51am UTC](https://discourse.julialang.org/t/matrix-inverse-as-objective/129162 "2025-05-20T05:51:58Z")

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Hi everyone, I am trying to solve a semi-definite program with an objective that contains a matrix inverse. More precisely, let a \\geq 0, and A be a positive definite matrix of size d \\times d. \\mathbf{1} below is a ve…

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## [IPOPT Watchdog Iterations Tracking](https://discourse.julialang.org/t/ipopt-watchdog-iterations-tracking/129159)

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**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 2\
**Last updated:** [May 19, 2025, 10:17pm UTC](https://discourse.julialang.org/t/ipopt-watchdog-iterations-tracking/129159 "2025-05-19T22:17:28Z")

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In IPOPT.jl, is there any way to obtain the diagnostic information or alpha\_pr? The callback function example given in repo is: function my\_callback( alg\_mod::Cint, iter\_count::Cint, obj\_value::Float64, inf…

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## [Simplicial decomposition equals dual cutting plane---a toy example](https://discourse.julialang.org/t/simplicial-decomposition-equals-dual-cutting-plane-a-toy-example/129128)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 1\
**Last updated:** [May 19, 2025, 7:36pm UTC](https://discourse.julialang.org/t/simplicial-decomposition-equals-dual-cutting-plane-a-toy-example/129128 "2025-05-19T19:36:28Z")

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Continuing the discussion from Seeking help on Branch and Price: I here furnish a toy example to help us fathoming that doing simplicial decomposition (or, column generation) in the primal space is equivalent to adding …

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## [Seeking help on Branch and Price](https://discourse.julialang.org/t/seeking-help-on-branch-and-price/112020)

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**Author:** [@wahadhasan](https://discourse.julialang.org/u/wahadhasan)\
**Replies:** 2\
**Last updated:** [May 19, 2025, 1:39am UTC](https://discourse.julialang.org/t/seeking-help-on-branch-and-price/112020 "2025-05-19T01:39:32Z")

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Note that this may not be the global minimum because we are not adding new columns during the solution of the mixed-integer problem model (an algorithm known as branch and price). Could someone please help me how to f…

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## [Using a trained MLJ model for prediction on non-Table objects](https://discourse.julialang.org/t/using-a-trained-mlj-model-for-prediction-on-non-table-objects/129071)

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**Author:** [@elipivo](https://discourse.julialang.org/u/elipivo)\
**Replies:** 1\
**Last updated:** [May 18, 2025, 9:42pm UTC](https://discourse.julialang.org/t/using-a-trained-mlj-model-for-prediction-on-non-table-objects/129071 "2025-05-18T21:42:09Z")

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After training an MLJ model on data that meets the Tables.jl interface requirements, I’m interested in then deploying these models into an environment where predict is called on objects that don’t necessarily meet the Ta…

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## [Monotonic smoothing of noisy data](https://discourse.julialang.org/t/monotonic-smoothing-of-noisy-data/93184)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 21\
**Last updated:** [May 17, 2025, 3:47pm UTC](https://discourse.julialang.org/t/monotonic-smoothing-of-noisy-data/93184 "2025-05-17T15:47:46Z")

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Is there a package in Julia, or a simple algorithm, to perform monotonic smoothing of noisy data? See this Python example. NB: it is assumed that we do not know of any monotonic function or model that could fit the da…

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## [RPRMakie.jl for 3D plotting of star](https://discourse.julialang.org/t/rprmakie-jl-for-3d-plotting-of-star/129107)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 0\
**Last updated:** [May 17, 2025, 6:46pm UTC](https://discourse.julialang.org/t/rprmakie-jl-for-3d-plotting-of-star/129107 "2025-05-17T18:46:23Z")

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What is current state of RPRMakie.jl @sdanisch? I want to create 3D volume plot of Neutron Star or Black Hole using RPRMakie.jl. I have HDF5 data of simulation. I would like to interactively visualize the internal parts …

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## [Do degeneracies and numerical instabilities more likely during the execution of solvers in case of formulations with greater number of constraints and decision variables?](https://discourse.julialang.org/t/do-degeneracies-and-numerical-instabilities-more-likely-during-the-execution-of-solvers-in-case-of-formulations-with-greater-number-of-constraints-and-decision-variables/129108)

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**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 2\
**Last updated:** [May 18, 2025, 2:23am UTC](https://discourse.julialang.org/t/do-degeneracies-and-numerical-instabilities-more-likely-during-the-execution-of-solvers-in-case-of-formulations-with-greater-number-of-constraints-and-decision-variables/129108 "2025-05-18T02:23:58Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve it using the SDDiP algorithm in the SDDP.jl package in Julia. In this regard, I am conducting prelimina…

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## [Gurobi Error 10005 is seen on submitting lazy constraint also when cb\_where == GRB\_CB\_MIPNODE](https://discourse.julialang.org/t/gurobi-error-10005-is-seen-on-submitting-lazy-constraint-also-when-cb-where-grb-cb-mipnode/129094)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 2\
**Last updated:** [May 18, 2025, 12:09am UTC](https://discourse.julialang.org/t/gurobi-error-10005-is-seen-on-submitting-lazy-constraint-also-when-cb-where-grb-cb-mipnode/129094 "2025-05-18T00:09:12Z")

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My code (full and runnable) is import LinearAlgebra.dot as dot import LinearAlgebra.norm as norm import JuMP, Gurobi, Random function my\_callback\_function(cb\_data, cb\_where::Cint) if cb\_where == Gurobi.GRB\_CB\_MIPSOL…

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## [Unable to solve the problem using Lagrangian duality handler](https://discourse.julialang.org/t/unable-to-solve-the-problem-using-lagrangian-duality-handler/129079)

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**Author:** [@Engr\_Moiz\_Ahmad](https://discourse.julialang.org/u/Engr_Moiz_Ahmad)\
**Replies:** 2\
**Last updated:** [May 17, 2025, 9:40pm UTC](https://discourse.julialang.org/t/unable-to-solve-the-problem-using-lagrangian-duality-handler/129079 "2025-05-17T21:40:17Z")

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I am dealing with a multi-stage mixed-integer stochastic global supply chain optimization problem and want to solve it using the SDDiP algorithm in the SDDP.jl package in Julia. In this regard, I tried solving the mixed…

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## [Best practices for flattening and reconstructing nested structs for ODEs, Solve, Kalman.jl etc](https://discourse.julialang.org/t/best-practices-for-flattening-and-reconstructing-nested-structs-for-odes-solve-kalman-jl-etc/129093)

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**Author:** [@stevenhughes](https://discourse.julialang.org/u/stevenhughes)\
**Replies:** 5\
**Last updated:** [May 17, 2025, 9:24pm UTC](https://discourse.julialang.org/t/best-practices-for-flattening-and-reconstructing-nested-structs-for-odes-solve-kalman-jl-etc/129093 "2025-05-17T21:24:19Z")

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Hello All, I’m prototyping a space/astrodynamics simulation and optimization framework in Julia. For the user interface, the most intuitive way to encapsulate all the data is on structs. Below is a toy example which i…

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## [Plotting a georeferenced field on a 3d globe](https://discourse.julialang.org/t/plotting-a-georeferenced-field-on-a-3d-globe/128895)

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**Author:** [@aasdelat](https://discourse.julialang.org/u/aasdelat)\
**Replies:** 5\
**Last updated:** [May 17, 2025, 4:25pm UTC](https://discourse.julialang.org/t/plotting-a-georeferenced-field-on-a-3d-globe/128895 "2025-05-17T16:25:53Z")

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I have georeferenced data in longitude/latitude, and I want to plot them on a three-dimensional globe with the WGS84 datum, using the GLMakie and GeoMakie libraries. You can download the data from here. The grid is irr…

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## [Write the lagrangian relaxation with JuMP concisely](https://discourse.julialang.org/t/write-the-lagrangian-relaxation-with-jump-concisely/129082)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 2\
**Last updated:** [May 17, 2025, 6:52am UTC](https://discourse.julialang.org/t/write-the-lagrangian-relaxation-with-jump-concisely/129082 "2025-05-17T06:52:33Z")

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I discover a new syntax to do the lagrangian relaxation, it looks elegant, but will it be efficiency also? # The following 2 constraints are to be relaxed (and penalized on the obj) # via Lagrangian multipliers \`a\` and…

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## [Gurobi12 reports obj\_value \< obj\_bound in a Min-Program?](https://discourse.julialang.org/t/gurobi12-reports-obj-value-obj-bound-in-a-min-program/126849)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 17\
**Last updated:** [May 11, 2025, 3:00pm UTC](https://discourse.julialang.org/t/gurobi12-reports-obj-value-obj-bound-in-a-min-program/126849 "2025-05-11T15:00:58Z")

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See the comments at the bottom of this code. import JuMP, Gurobi CR = JuMP.Model(() -\> Gurobi.Optimizer()) JuMP.@variable(CR, x\[1:3\]) JuMP.set\_lower\_bound(x\[1\], exp(1)); JuMP.set\_upper\_bound(x\[1\], exp(2)) JuMP.set\_lower…

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## [Issue with Optimization.LBFGS](https://discourse.julialang.org/t/issue-with-optimization-lbfgs/129076)

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**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 1\
**Last updated:** [May 16, 2025, 8:14pm UTC](https://discourse.julialang.org/t/issue-with-optimization-lbfgs/129076 "2025-05-16T20:14:50Z")

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Hi there, Disclaimer: I can not share the actual data or objective function so this might be a long shot but maybe the error itself has enough information. I am trying to optimize a function g with non-linear constrain…

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## [Struggling with LibSndFile.jl, WAV.jl outputs slightly non-standard 24bit PCM files](https://discourse.julialang.org/t/struggling-with-libsndfile-jl-wav-jl-outputs-slightly-non-standard-24bit-pcm-files/129044)

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**Author:** [@Perrin\_Meyer](https://discourse.julialang.org/u/Perrin_Meyer)\
**Replies:** 11\
**Last updated:** [May 16, 2025, 4:50pm UTC](https://discourse.julialang.org/t/struggling-with-libsndfile-jl-wav-jl-outputs-slightly-non-standard-24bit-pcm-files/129044 "2025-05-16T16:50:14Z")

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I’m struggling with loading a wav file using LibSndFile.jl julia\> using FileIO: load, save, loadstreaming, savestreaming julia\> import LibSndFile julia\> x = load("JolieHollandSacha.wav") (\[0.0 0.0; 0.0 0.0; … ; 0.0 0.…

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## [How to embed expert knowledge /constraints in ML training?](https://discourse.julialang.org/t/how-to-embed-expert-knowledge-constraints-in-ml-training/129025)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 11\
**Last updated:** [May 16, 2025, 2:34pm UTC](https://discourse.julialang.org/t/how-to-embed-expert-knowledge-constraints-in-ml-training/129025 "2025-05-16T14:34:00Z")

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I want to train a model to predict the timber volume growth in a forest as a function of pedological/site variables and climatic data. So, I have something like this: ip\_point X Y vol vol\_growth sand\_pc soil\_depth p…

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## [Linear interpolation given a triangulation in arbitrary dimensions](https://discourse.julialang.org/t/linear-interpolation-given-a-triangulation-in-arbitrary-dimensions/128998)

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**Author:** [@Pablo\_Marchant](https://discourse.julialang.org/u/Pablo_Marchant)\
**Replies:** 9\
**Last updated:** [May 16, 2025, 2:15pm UTC](https://discourse.julialang.org/t/linear-interpolation-given-a-triangulation-in-arbitrary-dimensions/128998 "2025-05-16T14:15:05Z")

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Hi all, I’m in need of the equivalent of LinearNDInterpolator in scipy for julia, in order to do interpolation of irregularly sampled points (not on a grid). There are existing packages such as NaturalNeighbours.jl, but…

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## [How to rotate mesh using observables in Makie?](https://discourse.julialang.org/t/how-to-rotate-mesh-using-observables-in-makie/129047)

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**Author:** [@jmo](https://discourse.julialang.org/u/jmo)\
**Replies:** 3\
**Last updated:** [May 16, 2025, 12:03pm UTC](https://discourse.julialang.org/t/how-to-rotate-mesh-using-observables-in-makie/129047 "2025-05-16T12:03:59Z")

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My aim is to rotate/translate a few objects (STL) in 3D visualizing a running simulation. And Makie seems to be the way to do it. I started simple with just trying to rotate a cube using an observable updated every 100 …

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## [How to Minimize Operator/Spectral Norm of a Density Matrix with JuMP + Hypatia](https://discourse.julialang.org/t/how-to-minimize-operator-spectral-norm-of-a-density-matrix-with-jump-hypatia/129006)

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**Author:** [@Menixm](https://discourse.julialang.org/u/Menixm)\
**Replies:** 7\
**Last updated:** [May 16, 2025, 11:57am UTC](https://discourse.julialang.org/t/how-to-minimize-operator-spectral-norm-of-a-density-matrix-with-jump-hypatia/129006 "2025-05-16T11:57:05Z")

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I am coming from MATLAB/Python but Julia is becoming more attractive, especially for higher precision. Currently I am just trying out some toy problems to familiarize myself with Julia, JuMP, and associated solvers. I a…

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## [Having a component whose equations refer another component](https://discourse.julialang.org/t/having-a-component-whose-equations-refer-another-component/128952)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 2\
**Last updated:** [May 16, 2025, 8:41am UTC](https://discourse.julialang.org/t/having-a-component-whose-equations-refer-another-component/128952 "2025-05-16T08:41:33Z")

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I have two components in ModelingToolkit.jl, and I want to have an equation across components, such as comp1.x ~ comp2.y. But I’d like that equation to only be there when Comp2() is used (I have an alternative GooeyComp2…

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## [Makie Draw on Colorbar](https://discourse.julialang.org/t/makie-draw-on-colorbar/128982)

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**Author:** [@andrew-saydjari](https://discourse.julialang.org/u/andrew-saydjari)\
**Replies:** 6\
**Last updated:** [May 15, 2025, 10:15pm UTC](https://discourse.julialang.org/t/makie-draw-on-colorbar/128982 "2025-05-15T22:15:44Z")

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I have been struggling to find the syntax for drawing a line on a color bar using CairoMakie. I just want to be able to get the colorbar axis and do something like hlines!(cbar.axis. 5, color=“red”).

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## [Does DuckDB not allow multiple connections?](https://discourse.julialang.org/t/does-duckdb-not-allow-multiple-connections/128856)

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**Author:** [@slwu89](https://discourse.julialang.org/u/slwu89)\
**Replies:** 3\
**Last updated:** [May 15, 2025, 3:27pm UTC](https://discourse.julialang.org/t/does-duckdb-not-allow-multiple-connections/128856 "2025-05-15T15:27:05Z")

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Hi all. Just curious if I am able to do something like the following MWE. I want to have 2 connections to a relational DB, one of which I can use for R/W and one which is read-only. The read only one I’d like to use FunS…

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## [Genie app with live, shared data](https://discourse.julialang.org/t/genie-app-with-live-shared-data/129030)

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**Author:** [@Joseph\_Bradley](https://discourse.julialang.org/u/Joseph_Bradley)\
**Replies:** 0\
**Last updated:** [May 15, 2025, 11:11am UTC](https://discourse.julialang.org/t/genie-app-with-live-shared-data/129030 "2025-05-15T11:11:27Z")

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I’m trying to make a Genie app that will let multiple users collaborate on a web app. It’s just a project tracker, but Excel isn’t quite enough for what we want. There will be a table df that exists on the cloud somewhe…

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## [Estimating parameter and function in an ODE model](https://discourse.julialang.org/t/estimating-parameter-and-function-in-an-ode-model/126109)

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**Author:** [@dg.aragones](https://discourse.julialang.org/u/dg.aragones)\
**Replies:** 11\
**Last updated:** [May 15, 2025, 9:50am UTC](https://discourse.julialang.org/t/estimating-parameter-and-function-in-an-ode-model/126109 "2025-05-15T09:50:17Z")

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Hi all, I’m working on an ODE model where I want to infer a parameter μ and a function ϕ(t), and I’m looking for recommendations for tools or approaches in Julia to solve this problem. My dataset is small, with just 7 d…

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