# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=37

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**Page:** 38

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## [Sparse GPU linear solve from documentation fails](https://discourse.julialang.org/t/sparse-gpu-linear-solve-from-documentation-fails/129834)

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**Author:** [@Jonas208](https://discourse.julialang.org/u/Jonas208)\
**Replies:** 2\
**Last updated:** [June 17, 2025, 10:57am UTC](https://discourse.julialang.org/t/sparse-gpu-linear-solve-from-documentation-fails/129834 "2025-06-17T10:57:22Z")

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To solve the Poisson equation on the GPU, I would like to use the interface from LinearSolve.jl to do a sparse linear solve. However, the following minimal reproducible example (also provided in the documentation) gives …

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## [How to make fly-through animations?](https://discourse.julialang.org/t/how-to-make-fly-through-animations/129775)

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**Author:** [@hsgg](https://discourse.julialang.org/u/hsgg)\
**Replies:** 6\
**Last updated:** [June 17, 2025, 4:54am UTC](https://discourse.julialang.org/t/how-to-make-fly-through-animations/129775 "2025-06-17T04:54:11Z")

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I am trying to use Makie.jl to create a nice 3D visualization of a galaxy survey. Essentially, I count the number of galaxies within a grid cell, and then use GLMakie.volume(vol). The interactive display is already prett…

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## [Time-plotting the derivative of a species (reaction velocity) in catalyst](https://discourse.julialang.org/t/time-plotting-the-derivative-of-a-species-reaction-velocity-in-catalyst/129927)

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**Author:** [@Andre\_Renard](https://discourse.julialang.org/u/Andre_Renard)\
**Replies:** 1\
**Last updated:** [June 16, 2025, 9:37pm UTC](https://discourse.julialang.org/t/time-plotting-the-derivative-of-a-species-reaction-velocity-in-catalyst/129927 "2025-06-16T21:37:32Z")

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Hello, I can’t find an easy way to time-plot a derivative of a species, although I’m sure data are stored somewhere. Thanks for help. Andre

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## [Need help wrapping cuOpt in julia](https://discourse.julialang.org/t/need-help-wrapping-cuopt-in-julia/129808)

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**Author:** [@mtanneau](https://discourse.julialang.org/u/mtanneau)\
**Replies:** 13\
**Last updated:** [June 16, 2025, 8:29pm UTC](https://discourse.julialang.org/t/need-help-wrapping-cuopt-in-julia/129808 "2025-06-16T20:29:07Z")

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NVIDIA recently open-sourced their cuOpt solver suite. The source code is mostly C++, and it has a C API. I’m looking into wrapping that in Julia and setting up a JuMP/MOI interface so we can use cuOpt through JuMP. I h…

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## [Getting value from unregistered variables](https://discourse.julialang.org/t/getting-value-from-unregistered-variables/129869)

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**Author:** [@nhebel](https://discourse.julialang.org/u/nhebel)\
**Replies:** 3\
**Last updated:** [June 16, 2025, 5:13pm UTC](https://discourse.julialang.org/t/getting-value-from-unregistered-variables/129869 "2025-06-16T17:13:22Z")

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Sorry if this has already been asked - I tried searching and re-reading the documentation and couldn’t find anything. I have a model with unregistered variables (though we did assign base names/strings) and I’m trying to…

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## [Issue with backprop in a custom recurrent \`Lux\` layer](https://discourse.julialang.org/t/issue-with-backprop-in-a-custom-recurrent-lux-layer/128968)

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**Author:** [@pietro-butti](https://discourse.julialang.org/u/pietro-butti)\
**Replies:** 6\
**Last updated:** [June 16, 2025, 3:44pm UTC](https://discourse.julialang.org/t/issue-with-backprop-in-a-custom-recurrent-lux-layer/128968 "2025-06-16T15:44:58Z")

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I am trying to implement an autoencoder in Lux, inspired by the excellent one that I found in githun.com/lkulowski/LSTM\_encoder\_decoder, coded with PyTorch. (diagram taken from the link) Model overview The encoder i…

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## [Scaling issues in a nonlinear program](https://discourse.julialang.org/t/scaling-issues-in-a-nonlinear-program/129835)

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**Author:** [@fmanfredini1](https://discourse.julialang.org/u/fmanfredini1)\
**Replies:** 2\
**Last updated:** [June 16, 2025, 9:29am UTC](https://discourse.julialang.org/t/scaling-issues-in-a-nonlinear-program/129835 "2025-06-16T09:29:06Z")

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Dear all, I’m trying to solve a non-linear constrained program. The program consists of minimizing the sum of the relative squared deviations between the data and their model counterpart. I’m doing it using IpOpt on JUMP…

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## [Covariance Optimization for Joint estimation using UKF](https://discourse.julialang.org/t/covariance-optimization-for-joint-estimation-using-ukf/129677)

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**Author:** [@vh94](https://discourse.julialang.org/u/vh94)\
**Replies:** 5\
**Last updated:** [June 16, 2025, 9:08am UTC](https://discourse.julialang.org/t/covariance-optimization-for-joint-estimation-using-ukf/129677 "2025-06-16T09:08:14Z")

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Hello, I am using an Unscented Kalman Filter to perform a joint state and parameter estimation. I am trying to improve the accuracy of the parameters estimation foremost ( fit to the measured data is less important) . F…

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## [JuMP.set\_upper\_bound on AffExpr?](https://discourse.julialang.org/t/jump-set-upper-bound-on-affexpr/129904)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 6\
**Last updated:** [June 16, 2025, 7:47am UTC](https://discourse.julialang.org/t/jump-set-upper-bound-on-affexpr/129904 "2025-06-16T07:47:06Z")

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Is it possible to extend the syntax of set\_upper\_bound to an expression, despite (perhaps) there might not be a corresponding solver API? Consider julia\> using JuMP julia\> model = Model(); julia\> @variable(model, x\[1…

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## [JuMP.NormOneCone()](https://discourse.julialang.org/t/jump-normonecone/129768)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 13\
**Last updated:** [June 15, 2025, 10:47pm UTC](https://discourse.julialang.org/t/jump-normonecone/129768 "2025-06-15T22:47:45Z")

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Can this NormOneCone be made easier? as SecondOrderCone is? It will find it use in linear programming. In my code, I now write something like nm1e = JuMP.@variable(outer) nm1c = JuMP.@constraint(outer, \[nm1e; vec(out…

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## [Block matrix linear solve performance](https://discourse.julialang.org/t/block-matrix-linear-solve-performance/129353)

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**Author:** [@Karajan](https://discourse.julialang.org/u/Karajan)\
**Replies:** 6\
**Last updated:** [June 15, 2025, 5:41pm UTC](https://discourse.julialang.org/t/block-matrix-linear-solve-performance/129353 "2025-06-15T17:41:51Z")

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Hi there! I have located a bottleneck in my simulations I could use some help with. I think this is mainly a linear algebra problem rather than pure Julia performance, but I know very little about that field so I’m not …

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## [SymbolicRegression stuck at version 0.22.2](https://discourse.julialang.org/t/symbolicregression-stuck-at-version-0-22-2/129823)

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**Author:** [@Sam\_P](https://discourse.julialang.org/u/Sam_P)\
**Replies:** 6\
**Last updated:** [June 15, 2025, 5:23am UTC](https://discourse.julialang.org/t/symbolicregression-stuck-at-version-0-22-2/129823 "2025-06-15T05:23:05Z")

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Hi all. Just playing around with SymbolicRegression.jl and notice the version kept getting stuck on v0.22.2 instead of the latest v1.11.1. And when I force install that version, the ForwardDiff.jl went from 1.0.1 down to…

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## [Pretty print summary statistics for a dataframe](https://discourse.julialang.org/t/pretty-print-summary-statistics-for-a-dataframe/129838)

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**Author:** [@theabhirath](https://discourse.julialang.org/u/theabhirath)\
**Replies:** 4\
**Last updated:** [June 15, 2025, 2:27am UTC](https://discourse.julialang.org/t/pretty-print-summary-statistics-for-a-dataframe/129838 "2025-06-15T02:27:29Z")

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I’m looking to print out a summary of missing values in each row and column for a dataframe, but ideally I want to print it alongside the actual dataframe itself – in my head it looks something like this (pardon the crud…

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## [Weird behavior of GraphNeuralNetworks.jl \`SGConv\` layer within \`Flux.withgradient\`](https://discourse.julialang.org/t/weird-behavior-of-graphneuralnetworks-jl-sgconv-layer-within-flux-withgradient/129701)

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**Author:** [@MackHarry](https://discourse.julialang.org/u/MackHarry)\
**Replies:** 5\
**Last updated:** [June 14, 2025, 4:34pm UTC](https://discourse.julialang.org/t/weird-behavior-of-graphneuralnetworks-jl-sgconv-layer-within-flux-withgradient/129701 "2025-06-14T16:34:32Z")

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First, I am quite new to Julia’s ML ecosystem, so I might have made stupid mistakes.. Recently, I tried to debug a very training loop involving GraphNeuralNetworks.jl’s SGConv layer, and found successively longer runti…

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## [Integrators with analytic derivatives w/r/t initial conditions (especially the independent variable)](https://discourse.julialang.org/t/integrators-with-analytic-derivatives-w-r-t-initial-conditions-especially-the-independent-variable/129832)

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**Author:** [@stevenhughes](https://discourse.julialang.org/u/stevenhughes)\
**Replies:** 2\
**Last updated:** [June 13, 2025, 12:43pm UTC](https://discourse.julialang.org/t/integrators-with-analytic-derivatives-w-r-t-initial-conditions-especially-the-independent-variable/129832 "2025-06-13T12:43:37Z")

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Hello, I am working on an application that requires derivatives odes to compute partials for solvers. The approach I am taking is to prefer analytic partials (for performance, which is key), and fallback to AD or finit…

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## [IOError: stream is closed or unusable on POST](https://discourse.julialang.org/t/ioerror-stream-is-closed-or-unusable-on-post/129859)

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**Author:** [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)\
**Replies:** 0\
**Last updated:** [June 13, 2025, 12:06pm UTC](https://discourse.julialang.org/t/ioerror-stream-is-closed-or-unusable-on-post/129859 "2025-06-13T12:06:25Z")

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I frequently get IOError: stream is closed or unusable when trying to POST to an API with a pretty large body: Content-Length: 406233. What can I do?

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## [Changing penalty parameter in objective function in JuMP](https://discourse.julialang.org/t/changing-penalty-parameter-in-objective-function-in-jump/129791)

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**Author:** [@Lester](https://discourse.julialang.org/u/Lester)\
**Replies:** 4\
**Last updated:** [June 13, 2025, 11:37am UTC](https://discourse.julialang.org/t/changing-penalty-parameter-in-objective-function-in-jump/129791 "2025-06-13T11:37:07Z")

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Hi Saying in JuMP, I want to a objective function being a conbination of the cost function f(x) and the constraint violation evaluation h(x), as @objective(model, Min, f(x) + μ \* h(x)). Is there a way for me to changeμ …

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## [Acausal component based modelling including neural network components](https://discourse.julialang.org/t/acausal-component-based-modelling-including-neural-network-components/99111)

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**Author:** [@Dhruva2](https://discourse.julialang.org/u/Dhruva2)\
**Replies:** 9\
**Last updated:** [June 13, 2025, 8:58am UTC](https://discourse.julialang.org/t/acausal-component-based-modelling-including-neural-network-components/99111 "2025-06-13T08:58:18Z")

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Hello all, A high level question. I want to do acausal, component-based modelling as on the ModelingToolkit.jl docs. In particular, I want to include some components that are neural networks. IE build a ‘universal dif…

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## [Define a recursive JuMP.@expression](https://discourse.julialang.org/t/define-a-recursive-jump-expression/129848)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 3\
**Last updated:** [June 13, 2025, 3:35am UTC](https://discourse.julialang.org/t/define-a-recursive-jump-expression/129848 "2025-06-13T03:35:35Z")

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Is this a good syntax that can be supported? julia\> using JuMP; model = Model(); julia\> x0 = 1.3; # initial state julia\> @variable(model, u\[t = 1:3\], Bin); # actions julia\> @expression(model, x\[t = 1:3\], (t == 1 ? x0…

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## [LowLevelParticleFilters compatibility with ComponentArrays](https://discourse.julialang.org/t/lowlevelparticlefilters-compatibility-with-componentarrays/129830)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 4\
**Last updated:** [June 12, 2025, 2:51pm UTC](https://discourse.julialang.org/t/lowlevelparticlefilters-compatibility-with-componentarrays/129830 "2025-06-12T14:51:37Z")

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I’m developing a Kalman Filter for a system that is made up of many components. Since the model is somewhat big I was hoping to use a ComponentArray to extract individual system (and subsystem) states from the state vec…

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## [Eigen produces non-normalized eigenvectors](https://discourse.julialang.org/t/eigen-produces-non-normalized-eigenvectors/129829)

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**Author:** [@nvenkov1](https://discourse.julialang.org/u/nvenkov1)\
**Replies:** 5\
**Last updated:** [June 12, 2025, 11:58am UTC](https://discourse.julialang.org/t/eigen-produces-non-normalized-eigenvectors/129829 "2025-06-12T11:58:48Z")

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I realized that, when using LinearAlgebra.jl’s eigen function to solve a general eigenvalue problem for a matrix pencil (A, B), the eigenvectors returned do not seem to be normalized in any way. The standard in the numer…

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## [Speeding up combination of Funs](https://discourse.julialang.org/t/speeding-up-combination-of-funs/129400)

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**Author:** [@nilsbecker](https://discourse.julialang.org/u/nilsbecker)\
**Replies:** 15\
**Last updated:** [June 11, 2025, 1:28pm UTC](https://discourse.julialang.org/t/speeding-up-combination-of-funs/129400 "2025-06-11T13:28:48Z")

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I’m building up an ApproxFun.Fun by successively multiplying a lot of individual factors along a graph. The individual factors are themselves also Funs. The situation is similar to this fake code factors = \[\] for n in …

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## [A toy example triggering Gurobi's Warning: Model contains variables with very large bounds participating in product terms](https://discourse.julialang.org/t/a-toy-example-triggering-gurobis-warning-model-contains-variables-with-very-large-bounds-participating-in-product-terms/127295)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 13\
**Last updated:** [June 11, 2025, 7:32pm UTC](https://discourse.julialang.org/t/a-toy-example-triggering-gurobis-warning-model-contains-variables-with-very-large-bounds-participating-in-product-terms/127295 "2025-06-11T19:32:30Z")

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It’s common to find Gurobi logging the following Warning in QCP Warning: Model contains variables with very large bounds participating in product terms. Presolve was not able to compute smaller bounds for these variabl…

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## [ParametricOptInterface + Clarabel](https://discourse.julialang.org/t/parametricoptinterface-clarabel/129745)

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**Author:** [@klamike](https://discourse.julialang.org/u/klamike)\
**Replies:** 5\
**Last updated:** [June 11, 2025, 2:25pm UTC](https://discourse.julialang.org/t/parametricoptinterface-clarabel/129745 "2025-06-11T14:25:46Z")

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I am trying to use POI with Clarabel. Based on the ParametricOptInterface.jl readme, the recommended usage is with direct\_model. Here, I’ve just swapped HiGHS.jl for Clarabel.jl: using JuMP, Clarabel import ParametricOp…

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## [Array and clocked signal](https://discourse.julialang.org/t/array-and-clocked-signal/129778)

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**Author:** [@yjr](https://discourse.julialang.org/u/yjr)\
**Replies:** 2\
**Last updated:** [June 11, 2025, 1:26pm UTC](https://discourse.julialang.org/t/array-and-clocked-signal/129778 "2025-06-11T13:26:54Z")

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Hello, I m basically trying to implement a PRBS or similar signal generator using vector and discrete clock signal. But it does not seem that both can be handled simultaenously. Am I right or is there a way to use both …

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## [Histogram equalization with OpenCV](https://discourse.julialang.org/t/histogram-equalization-with-opencv/126421)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 2\
**Last updated:** [June 11, 2025, 11:42am UTC](https://discourse.julialang.org/t/histogram-equalization-with-opencv/126421 "2025-06-11T11:42:13Z")

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I am using OpenCV.jl for image processing and I want to increase the contrast of an image using adaptive histogram equalization. I can create the CLAHE object with OpenCV.createCLAHE, but that is an “C++ smart pointer of…

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## [Native Julia FID (Fréchet Inception Distance) Computation](https://discourse.julialang.org/t/native-julia-fid-frechet-inception-distance-computation/129798)

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**Author:** [@josemanuel22](https://discourse.julialang.org/u/josemanuel22)\
**Replies:** 0\
**Last updated:** [June 11, 2025, 10:00am UTC](https://discourse.julialang.org/t/native-julia-fid-frechet-inception-distance-computation/129798 "2025-06-11T10:00:18Z")

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Is there a relatively simple way to calculate the FID (Fréchet Inception Distance) metric in Julia? Metalhead doesn’t include a pre-trained Inception-v3 model. I know you can try ONNX or PythonCall (though all of those h…

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## [Solving inference problem in quantum error correction with Turing.jl](https://discourse.julialang.org/t/solving-inference-problem-in-quantum-error-correction-with-turing-jl/129753)

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**Author:** [@nzy1997](https://discourse.julialang.org/u/nzy1997)\
**Replies:** 4\
**Last updated:** [June 11, 2025, 8:17am UTC](https://discourse.julialang.org/t/solving-inference-problem-in-quantum-error-correction-with-turing-jl/129753 "2025-06-11T08:17:54Z")

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Hi everyone, I am trying to use Turing.jl to solve an inference problem in quantum error correction. Here is a simple problem. Problem Statement: Consider a parity check bit c \\in \\{0,1\\} computed from four binary var…

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## [JuMP.shadow\_price conveys a misconception?](https://discourse.julialang.org/t/jump-shadow-price-conveys-a-misconception/127503)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 5\
**Last updated:** [June 11, 2025, 7:44am UTC](https://discourse.julialang.org/t/jump-shadow-price-conveys-a-misconception/127503 "2025-06-11T07:44:19Z")

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In constraint optimization, the shadow price is the change, per infinitesimal unit of the constraint, in the optimal value of the objective function, obtained by relaxing the constraint. This is the wikipedia definiti…

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## [Code fails using BoundaryValueDiffEq Version 5.18.0](https://discourse.julialang.org/t/code-fails-using-boundaryvaluediffeq-version-5-18-0/129793)

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**Author:** [@ThermionicsGuy](https://discourse.julialang.org/u/ThermionicsGuy)\
**Replies:** 5\
**Last updated:** [June 11, 2025, 3:45am UTC](https://discourse.julialang.org/t/code-fails-using-boundaryvaluediffeq-version-5-18-0/129793 "2025-06-11T03:45:57Z")

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I had a code working using the MIRK4 boundary value problem solver from SciML. Yesterday I updated BoundaryValueDiffEq to Version 5.18.0 and now the same code errors out. I’m using Julia 1.11.5. Here is a code fragment, …

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