# Latest

**URL:** https://discourse.julialang.org/latest.md?page=59

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 60

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## [Julia vs NumPy array comparison](https://discourse.julialang.org/t/julia-vs-numpy-array-comparison/135238)

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**Author:** [@nturneroran](https://discourse.julialang.org/u/nturneroran)\
**Replies:** 8\
**Last updated:** [January 31, 2026, 6:34am UTC](https://discourse.julialang.org/t/julia-vs-numpy-array-comparison/135238 "2026-01-31T06:34:33Z")

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I’m trying Julia for a personal project after working in Python for school. With NumPy a = np.arange(0,10); np.array\_equal(a,a.T) gives True as the result. In Julia, a = range(0, length=10); a == transpose(a) or a == a…

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## [Savefig causes a flash on the display](https://discourse.julialang.org/t/savefig-causes-a-flash-on-the-display/56647)

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**Author:** [@LeePhillips](https://discourse.julialang.org/u/LeePhillips)\
**Replies:** 2\
**Last updated:** [January 30, 2026, 8:46pm UTC](https://discourse.julialang.org/t/savefig-causes-a-flash-on-the-display/56647 "2026-01-30T20:46:02Z")

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Calling savefig(“file”) writes the file, and the plots are as expected. But every call causes the screen to flash. I believe the plot is momentarily displayed and the plot window removed before the file is written. Runni…

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## [Skip empty entries of sparse matrix when plotting a heatmap](https://discourse.julialang.org/t/skip-empty-entries-of-sparse-matrix-when-plotting-a-heatmap/135343)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 5\
**Last updated:** [January 30, 2026, 8:11pm UTC](https://discourse.julialang.org/t/skip-empty-entries-of-sparse-matrix-when-plotting-a-heatmap/135343 "2026-01-30T20:11:30Z")

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I want to plot a sparse matrix as a heatmap, something like this: julia\> using Plots, SparseArrays julia\> x = sprand(Float64, 5, 5, 0.5) 5×5 SparseMatrixCSC{Float64, Int64} with 11 stored entries: ⋅ ⋅ …

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## [Are the Symbolics.jl docs outdated?](https://discourse.julialang.org/t/are-the-symbolics-jl-docs-outdated/135212)

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**Author:** [@twcawm](https://discourse.julialang.org/u/twcawm)\
**Replies:** 5\
**Last updated:** [January 30, 2026, 8:06pm UTC](https://discourse.julialang.org/t/are-the-symbolics-jl-docs-outdated/135212 "2026-01-30T20:06:27Z")

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I’m relatively new to Julia and have been having some trouble following the docs for Symbolics.jl ; not sure if I am misunderstanding something. (I am looking at the “stable” version of Symbolics.jl docs, in the “variab…

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## [Getting revise to work with symlink'ed .julia folder](https://discourse.julialang.org/t/getting-revise-to-work-with-symlinked-julia-folder/135363)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 0\
**Last updated:** [January 30, 2026, 7:23pm UTC](https://discourse.julialang.org/t/getting-revise-to-work-with-symlinked-julia-folder/135363 "2026-01-30T19:23:30Z")

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I work on some form of shared system, where I don’t have much space allocation. Since the .julia folder can get quite large with various stuff, I have put it on a (less fancily backed up\_ scratch folder, and replaced by …

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## [\[ANN\] GenieTest.jl](https://discourse.julialang.org/t/ann-genietest-jl/135350)

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**Author:** [@hhaensel](https://discourse.julialang.org/u/hhaensel)\
**Replies:** 0\
**Last updated:** [January 30, 2026, 3:53pm UTC](https://discourse.julialang.org/t/ann-genietest-jl/135350 "2026-01-30T15:53:54Z")

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Happy to announce GenieTest.jl for testing, debugging and development of GenieFramework Apps GenieTest A Julia package for testing Stipple/Genie applications with integrated frontend support. Overview GenieTest provide…

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## [Improve performance of this index creation and accessing code](https://discourse.julialang.org/t/improve-performance-of-this-index-creation-and-accessing-code/134235)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 65\
**Last updated:** [January 30, 2026, 3:47pm UTC](https://discourse.julialang.org/t/improve-performance-of-this-index-creation-and-accessing-code/134235 "2026-01-30T15:47:32Z")

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How to improve the performance of clp(j) function given below. Please suggest faster version of this code. I am converting spherical coordinates to Cartesian and placing color values to exact location in data. Otherwise…

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## [ElasticWave2D.jl - 2D seismic wave simulation on your laptop](https://discourse.julialang.org/t/elasticwave2d-jl-2d-seismic-wave-simulation-on-your-laptop/135349)

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**Author:** [@Wuheng10086](https://discourse.julialang.org/u/Wuheng10086)\
**Replies:** 0\
**Last updated:** [January 30, 2026, 2:32pm UTC](https://discourse.julialang.org/t/elasticwave2d-jl-2d-seismic-wave-simulation-on-your-laptop/135349 "2026-01-30T14:32:30Z")

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Hi, everyone! I made ElasticWave2D.jl — GPU-accelerated 2D elastic wave simulation in Julia. I wanted to explore Julia’s potential for seismic simulation — easy install, GPU support, and readable code. Features: C…

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## [How to trace positions of agents](https://discourse.julialang.org/t/how-to-trace-positions-of-agents/135340)

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**Author:** [@ahcvankampen](https://discourse.julialang.org/u/ahcvankampen)\
**Replies:** 5\
**Last updated:** [January 30, 2026, 12:23pm UTC](https://discourse.julialang.org/t/how-to-trace-positions-of-agents/135340 "2026-01-30T12:23:39Z")

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Hi, I have a multiagent model and want to extract agent data from this model. In one of the tutorial examples we have something like: adata = \[(cd4, count), (cd8, count), (dc, count)\] fig, ax, abmobs = abmplot(ln\_mode…

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## [Are LLVM/rust's floating-point issues on 32-bit platforms relevant to Julia?](https://discourse.julialang.org/t/are-llvm-rusts-floating-point-issues-on-32-bit-platforms-relevant-to-julia/133852)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 2\
**Last updated:** [January 30, 2026, 12:21pm UTC](https://discourse.julialang.org/t/are-llvm-rusts-floating-point-issues-on-32-bit-platforms-relevant-to-julia/133852 "2026-01-30T12:21:39Z")

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I noticed: This is an LLVM bug: rustc is generating LLVM IR with the intended semantics This is about Rust, but might translate to Julia (and more) since both use LLVM?! Both have tier 1 support for 32-bit on Win…

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## [How to run a Julia package using Visual Studio Code?](https://discourse.julialang.org/t/how-to-run-a-julia-package-using-visual-studio-code/135338)

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**Author:** [@xulongxu](https://discourse.julialang.org/u/xulongxu)\
**Replies:** 3\
**Last updated:** [January 30, 2026, 11:31am UTC](https://discourse.julialang.org/t/how-to-run-a-julia-package-using-visual-studio-code/135338 "2026-01-30T11:31:58Z")

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I am reading the article - “Quasinormal mode/grey-body factor correspondence for Kerr black holes”, which use the the following pacakge to compute the the QNM frequencies of the fundamental mode and the first overto…

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## [Pre-built binaries via the registry](https://discourse.julialang.org/t/pre-built-binaries-via-the-registry/134515)

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**Author:** [@mattsignorelli](https://discourse.julialang.org/u/mattsignorelli)\
**Replies:** 15\
**Last updated:** [January 30, 2026, 10:07am UTC](https://discourse.julialang.org/t/pre-built-binaries-via-the-registry/134515 "2026-01-30T10:07:08Z")

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Right now precompilation is run on users’ computers after they add a package. Sometimes these can take a very long time (e.g. Makie.jl or DifferentialEquations.jl). Sure, you only have to do it once, but then you have to…

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## [Parameter sharing and abstraction in MTK](https://discourse.julialang.org/t/parameter-sharing-and-abstraction-in-mtk/135269)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 3\
**Last updated:** [January 30, 2026, 9:26am UTC](https://discourse.julialang.org/t/parameter-sharing-and-abstraction-in-mtk/135269 "2026-01-30T09:26:27Z")

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I have started using ParametrizedInterpolation from the standard library in my code, and while it works fine, having to add a clock to each component that uses it tarnishes the code a bit. So I wrote this: """ A step fu…

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## [GC problems with \`jl\_gc\_unsafe\_enter\` with multithreaded embedding](https://discourse.julialang.org/t/gc-problems-with-jl-gc-unsafe-enter-with-multithreaded-embedding/104467)

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**Author:** [@Keluaa](https://discourse.julialang.org/u/Keluaa)\
**Replies:** 3\
**Last updated:** [January 30, 2026, 7:39am UTC](https://discourse.julialang.org/t/gc-problems-with-jl-gc-unsafe-enter-with-multithreaded-embedding/104467 "2026-01-30T07:39:26Z")

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I am currently developping a Kotlin library to embed Julia in the JVM, with the goal to support multithreading with jl\_adopt\_thread(). The main issue is that when using some frameworks, there may not be a way to be in co…

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## [Which version of JuliaFormatter is used in VS code?](https://discourse.julialang.org/t/which-version-of-juliaformatter-is-used-in-vs-code/127885)

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**Author:** [@dharasim](https://discourse.julialang.org/u/dharasim)\
**Replies:** 5\
**Last updated:** [January 30, 2026, 2:12am UTC](https://discourse.julialang.org/t/which-version-of-juliaformatter-is-used-in-vs-code/127885 "2026-01-30T02:12:48Z")

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I would like to know which version of JuliaFormatter.jl is used by the Julia extension for VS Code when I run the command Format Document. I don’t have JuliaFormatter in my global env and also not in my current project e…

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## [Converting cartesian index to what it would be in view](https://discourse.julialang.org/t/converting-cartesian-index-to-what-it-would-be-in-view/135310)

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**Author:** [@croberts](https://discourse.julialang.org/u/croberts)\
**Replies:** 4\
**Last updated:** [January 29, 2026, 10:37pm UTC](https://discourse.julialang.org/t/converting-cartesian-index-to-what-it-would-be-in-view/135310 "2026-01-29T22:37:01Z")

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Suppose we have a = CartesianIndices((3,3)) b = a\[2:3, :\] indx = CartesianIndex((3,3)) map\_index\_to\_what\_it\_would\_be\_in\_slice(?, indx::CartesianIndex) = ? using Test @test a\[indx\] == b\[map\_index\_to\_what\_it\_would\_be…

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## [Keyword arguments of 32-bit type don't work](https://discourse.julialang.org/t/keyword-arguments-of-32-bit-type-dont-work/135311)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 6\
**Last updated:** [January 29, 2026, 5:37pm UTC](https://discourse.julialang.org/t/keyword-arguments-of-32-bit-type-dont-work/135311 "2026-01-29T17:37:28Z")

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Why 32bit keyword argument functions give error (Int32 also) ? julia\> x = 2 2 julia\> function sixty\_four(x; y::Float64=0.5) x+y end sixty\_four (generic function with 1 method) julia\> function thi…

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## [\[ANN\] PortfolioOptimisers.jl](https://discourse.julialang.org/t/ann-portfoliooptimisers-jl/135325)

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**Author:** [@dcelisgarza](https://discourse.julialang.org/u/dcelisgarza)\
**Replies:** 0\
**Last updated:** [January 29, 2026, 4:26pm UTC](https://discourse.julialang.org/t/ann-portfoliooptimisers-jl/135325 "2026-01-29T16:26:05Z")

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PortfolioOptimisers.jl I noticed Julia there was no comprehensive portfolio optimisation package, so I made one. It has a huge number of features, many of them composable, so the world is your oyster. I’m still actively…

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## [Flexible linear constraints for MPC and codegen](https://discourse.julialang.org/t/flexible-linear-constraints-for-mpc-and-codegen/135285)

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**Author:** [@franckgaga](https://discourse.julialang.org/u/franckgaga)\
**Replies:** 10\
**Last updated:** [January 29, 2026, 4:19pm UTC](https://discourse.julialang.org/t/flexible-linear-constraints-for-mpc-and-codegen/135285 "2026-01-29T16:19:39Z")

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Following the subject \[ANN\] ModelPredictiveControl.jl with @langestefan and @darnstrom: The expressiveness of the linear MPC framework is already very limited and the current syntax limits it further. As long as my exp…

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## [Julia in Colab](https://discourse.julialang.org/t/julia-in-colab/126600)

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**Author:** [@metrizable](https://discourse.julialang.org/u/metrizable)\
**Replies:** 57\
**Last updated:** [January 29, 2026, 2:22pm UTC](https://discourse.julialang.org/t/julia-in-colab/126600 "2026-01-29T14:22:58Z")

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Hi Julia community! I’m new to posting here (this is my first one :-)) and wasn’t sure the right place to post, but I’d like to share that Colab now provides the Julia language in our runtimes (Julia as a language in ru…

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## [How to manage environments in Colab?](https://discourse.julialang.org/t/how-to-manage-environments-in-colab/132435)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 1\
**Last updated:** [January 29, 2026, 2:06pm UTC](https://discourse.julialang.org/t/how-to-manage-environments-in-colab/132435 "2026-01-29T14:06:46Z")

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Newby of colab here.. how do environments, that in local installations are directory-based, are managed in colab notebooks? How do I “save” one environment between multiple runs of the notebook (so not to precompile ever…

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## [Plots.jl: QPaintDevice: Cannot destroy paint device that is being painted \[SOLVED\]](https://discourse.julialang.org/t/plots-jl-qpaintdevice-cannot-destroy-paint-device-that-is-being-painted-solved/135323)

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**Author:** [@ericsfraga](https://discourse.julialang.org/u/ericsfraga)\
**Replies:** 1\
**Last updated:** [January 29, 2026, 1:46pm UTC](https://discourse.julialang.org/t/plots-jl-qpaintdevice-cannot-destroy-paint-device-that-is-being-painted-solved/135323 "2026-01-29T13:46:15Z")

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Good morning. Anybody here using the Plots.jl package for Julia? I am trying to generate some plots in files without having them display on the screen. I have a sequence of plt = plot(...) plot!(plt, ...) plot!(plt, ...…

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## [Force MTK to generate explicit ODEs?](https://discourse.julialang.org/t/force-mtk-to-generate-explicit-odes/135245)

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**Author:** [@benjamin](https://discourse.julialang.org/u/benjamin)\
**Replies:** 9\
**Last updated:** [January 29, 2026, 1:30pm UTC](https://discourse.julialang.org/t/force-mtk-to-generate-explicit-odes/135245 "2026-01-29T13:30:05Z")

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Hi! I am using ModelingToolkit.jl to model a physical system. The compiler generates an index-1 DAE, which works great for simulation. However, I need to use a standard Kalman Filter, which requires a minimal state-spa…

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## [Resize!(matrix)](https://discourse.julialang.org/t/resize-matrix/2379)

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**Author:** [@gdkrmr](https://discourse.julialang.org/u/gdkrmr)\
**Replies:** 51\
**Last updated:** [January 29, 2026, 12:59pm UTC](https://discourse.julialang.org/t/resize-matrix/2379 "2026-01-29T12:59:04Z")

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is it possible to resize an Array with more than one dimension? For example: tmp1 = collect(1:6) @show pointer(tmp1) for i in 1:5 resize!(tmp1, length(tmp1) + 2) @show pointer(tmp1) tmp2 = reshape(tmp1, 2…

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## [SparseArrays vs CUSPARSE](https://discourse.julialang.org/t/sparsearrays-vs-cusparse/135320)

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**Author:** [@rcalxrc08](https://discourse.julialang.org/u/rcalxrc08)\
**Replies:** 0\
**Last updated:** [January 29, 2026, 10:55am UTC](https://discourse.julialang.org/t/sparsearrays-vs-cusparse/135320 "2026-01-29T10:55:13Z")

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I have no idea if this is intentional or not, at the moment there is an inconstency in the julia and or CUDA stack when dense and sparse vectors are interacting: using SparseArrays, CUDA N=10 x\_cpu=randn(N); x\_sparse=sp…

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## [Stokes solver as an ODEproblem takes time to initiate](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317)

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**Author:** [@Iddingsite](https://discourse.julialang.org/u/Iddingsite)\
**Replies:** 6\
**Last updated:** [January 29, 2026, 10:15am UTC](https://discourse.julialang.org/t/stokes-solver-as-an-odeproblem-takes-time-to-initiate/135317 "2026-01-29T10:15:42Z")

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Hi everyone. I wrote a small code to solve 2D linear visco-elastic Stokes using finite difference and OrdinaryDiffEq to test how that would work out. So, in this case, I only have algebraic equations and have some param…

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## [Jupyter notebook -- saving code to file?](https://discourse.julialang.org/t/jupyter-notebook-saving-code-to-file/135307)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 7\
**Last updated:** [January 29, 2026, 9:22am UTC](https://discourse.julialang.org/t/jupyter-notebook-saving-code-to-file/135307 "2026-01-29T09:22:45Z")

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I’m using Jupyter notebooks in VSCode to do computations that I want to include in a word processor (LyX for now). Generating plots is no problem: I just save them to file, and link the plots into the word processor. Q…

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## [Sometimes no objective\_bound info from an LP solve, by Gurobi](https://discourse.julialang.org/t/sometimes-no-objective-bound-info-from-an-lp-solve-by-gurobi/135080)

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**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 13\
**Last updated:** [January 29, 2026, 7:35am UTC](https://discourse.julialang.org/t/sometimes-no-objective-bound-info-from-an-lp-solve-by-gurobi/135080 "2026-01-29T07:35:35Z")

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I solved an LP by Gurobi using Non-default parameters: Method 6 Crossover 0 PDHGGPU 1 And here’s the result julia\> model A JuMP Model ├ mode: DIRECT ├ solver: Gurobi ├ objective\_sense: MIN\_SENSE │ └ objective\_funct…

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## [Using SymbolicRegression on binary data?](https://discourse.julialang.org/t/using-symbolicregression-on-binary-data/135314)

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**Author:** [@atthom](https://discourse.julialang.org/u/atthom)\
**Replies:** 0\
**Last updated:** [January 28, 2026, 11:52pm UTC](https://discourse.julialang.org/t/using-symbolicregression-on-binary-data/135314 "2026-01-28T23:52:41Z")

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I was fiddling with the excellent SymbolicRegression.jl when I had issue executing this code: using SymbolicRegression A = rand(Bool, (1000, 5)) B = @. (A\[:, 1\] | A\[:, 2\]) & (!A\[:, 3\]) ⊻ A\[:, 4\] # Define options for s…

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## [Pretty-printing small n-d arrays](https://discourse.julialang.org/t/pretty-printing-small-n-d-arrays/135200)

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**Author:** [@rokke](https://discourse.julialang.org/u/rokke)\
**Replies:** 18\
**Last updated:** [January 28, 2026, 11:45pm UTC](https://discourse.julialang.org/t/pretty-printing-small-n-d-arrays/135200 "2026-01-28T23:45:53Z")

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I haven’t really looked at anything yet; I figured this might be small enough to be a first contribution, but I first wanted to ask if it would be welcome before I spent a bunch of time on it. I really like the terminal…

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