# Latest

**URL:** https://discourse.julialang.org/latest.md?page=229

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

**Page:** 230

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## [Too many dots](https://discourse.julialang.org/t/too-many-dots/125293)

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**Author:** [@henrikjaerleblad](https://discourse.julialang.org/u/henrikjaerleblad)\
**Replies:** 10\
**Last updated:** [January 28, 2025, 2:13pm UTC](https://discourse.julialang.org/t/too-many-dots/125293 "2025-01-28T14:13:59Z")

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EDIT: In the original version of this post, I included the exact expression for computing the jac output. This allowed other users to run performance tests on dot vs scalar versions of the function. However, I realized t…

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## [Why using JuMP or AMPL gives different number of nonzeros in Lagrangian Hessian?](https://discourse.julialang.org/t/why-using-jump-or-ampl-gives-different-number-of-nonzeros-in-lagrangian-hessian/125259)

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**Author:** [@slmontes](https://discourse.julialang.org/u/slmontes)\
**Replies:** 4\
**Last updated:** [January 28, 2025, 1:39pm UTC](https://discourse.julialang.org/t/why-using-jump-or-ampl-gives-different-number-of-nonzeros-in-lagrangian-hessian/125259 "2025-01-28T13:39:09Z")

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Hello, I was comparing NLP optimization between JuMP and AMPL and noticed that even when the problems are identical and the presolve option is turned off in AMPL, the number of nonzeros in Lagrangian Hessian varies. Th…

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## [Current emacs recommendations?](https://discourse.julialang.org/t/current-emacs-recommendations/109008)

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**Author:** [@mihalybaci](https://discourse.julialang.org/u/mihalybaci)\
**Replies:** 23\
**Last updated:** [January 28, 2025, 12:48pm UTC](https://discourse.julialang.org/t/current-emacs-recommendations/109008 "2025-01-28T12:48:30Z")

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For some reason I don’t understand, I thought I might try out emacs again 16 years after I decided I hate it. I like using hot keys and shortcuts more now, so maybe that’s it. When I looked at the emacs page, I learned …

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## [An interesting physics-based game](https://discourse.julialang.org/t/an-interesting-physics-based-game/124682)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 18\
**Last updated:** [January 28, 2025, 12:45pm UTC](https://discourse.julialang.org/t/an-interesting-physics-based-game/124682 "2025-01-28T12:45:19Z")

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I recently had some time off and built this game that I think turned out well (enough): I suspect some folks in this community might get a kick out of it. Feel free to provide any feedback!

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## [Write access to python numpy arrays encapsulated in a list from julia with PyCall](https://discourse.julialang.org/t/write-access-to-python-numpy-arrays-encapsulated-in-a-list-from-julia-with-pycall/125288)

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**Author:** [@mesonepigreco](https://discourse.julialang.org/u/mesonepigreco)\
**Replies:** 2\
**Last updated:** [January 28, 2025, 12:44pm UTC](https://discourse.julialang.org/t/write-access-to-python-numpy-arrays-encapsulated-in-a-list-from-julia-with-pycall/125288 "2025-01-28T12:44:14Z")

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Dear julianers, I am facing an issue trying to use a library I have in Python inside Julia. In particular, I need to modify the elements of a numpy array, which is stored inside a Python list from Julia using PyCall. H…

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## [Where does Juliaup store the julia binaries](https://discourse.julialang.org/t/where-does-juliaup-store-the-julia-binaries/125291)

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**Author:** [@xvries](https://discourse.julialang.org/u/xvries)\
**Replies:** 3\
**Last updated:** [January 28, 2025, 12:33pm UTC](https://discourse.julialang.org/t/where-does-juliaup-store-the-julia-binaries/125291 "2025-01-28T12:33:20Z")

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I have installed multiple julia version with juliaup. I was wondering where these are stored by default (on linux). I can not seem to find them anywhere.

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## [Can Julia implement experiment animations similar to those in OpenAI Gym?](https://discourse.julialang.org/t/can-julia-implement-experiment-animations-similar-to-those-in-openai-gym/99426)

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**Author:** [@WuSiren](https://discourse.julialang.org/u/WuSiren)\
**Replies:** 12\
**Last updated:** [January 28, 2025, 11:39am UTC](https://discourse.julialang.org/t/can-julia-implement-experiment-animations-similar-to-those-in-openai-gym/99426 "2025-01-28T11:39:01Z")

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When doing reinforcement learning tasks, OpenAI Gym is commonly used for experimentation, for example, solving classic problems such as Cart Pole and Pendulum. While ReinforcementLearning.jl also has built-in environment…

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## [Reinforcement learning packages for CartPole example with Julia v1.11 or v1.10?](https://discourse.julialang.org/t/reinforcement-learning-packages-for-cartpole-example-with-julia-v1-11-or-v1-10/125261)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 2\
**Last updated:** [January 28, 2025, 11:10am UTC](https://discourse.julialang.org/t/reinforcement-learning-packages-for-cartpole-example-with-julia-v1-11-or-v1-10/125261 "2025-01-28T11:10:16Z")

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I’ve been looking at reinforcement learning packages in Julia. Some of them are unfortunately slightly out of maintenance and have broken dependencies. Does anyone have a fully working CartPole training example (a well k…

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## [Big Float epsilon always the same independant of precision?](https://discourse.julialang.org/t/big-float-epsilon-always-the-same-independant-of-precision/125295)

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**Author:** [@Fourier](https://discourse.julialang.org/u/Fourier)\
**Replies:** 0\
**Last updated:** [January 28, 2025, 11:02am UTC](https://discourse.julialang.org/t/big-float-epsilon-always-the-same-independant-of-precision/125295 "2025-01-28T11:02:58Z")

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When I allocate a big float, I can set the precison as a keyword argument, like so: eps(BigFloat(1.0, precision=10)) However I always seem to get the same floating point epsilon for some reason, no matter the precision…

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## [\[ANN\] ToyPublicKeys.jl - Public key cryptography](https://discourse.julialang.org/t/ann-toypublickeys-jl-public-key-cryptography/125239)

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**Author:** [@NegaScout](https://discourse.julialang.org/u/NegaScout)\
**Replies:** 5\
**Last updated:** [January 28, 2025, 10:59am UTC](https://discourse.julialang.org/t/ann-toypublickeys-jl-public-key-cryptography/125239 "2025-01-28T10:59:53Z")

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Hello everyone! I’m happy to announce the first registered version of ToyPublicKeys, a mostly\* Julia-native implementation of public-key cryptographic protocols\*\*. Public key cryptography is a key pillar of the modern i…

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## [NonLinearRange](https://discourse.julialang.org/t/nonlinearrange/125221)

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**Author:** [@RainerHeintzmann](https://discourse.julialang.org/u/RainerHeintzmann)\
**Replies:** 7\
**Last updated:** [January 28, 2025, 8:58am UTC](https://discourse.julialang.org/t/nonlinearrange/125221 "2025-01-28T08:58:54Z")

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I was looking for way to way to allow multi-kernel broadcasting to act also over non-linear ranges. E.g. consider a complex exponential exp.(1im .\* k0 .\* x) with k0=1.35 being a scalar and x=0:255 a linear range. This …

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## [Problem with installing PythonPlot, CondaPKG (FreeBSD)](https://discourse.julialang.org/t/problem-with-installing-pythonplot-condapkg-freebsd/125195)

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**Author:** [@ko56](https://discourse.julialang.org/u/ko56)\
**Replies:** 4\
**Last updated:** [January 28, 2025, 2:51am UTC](https://discourse.julialang.org/t/problem-with-installing-pythonplot-condapkg-freebsd/125195 "2025-01-28T02:51:02Z")

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I posted this question micromamba a while ago, but haven’t gotten any responses. Maybe the post was in the wrong place. I am reposting here, which seems more appropriate. Thanks for any help.

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## [Packing and unpacking an array of N-bit ints](https://discourse.julialang.org/t/packing-and-unpacking-an-array-of-n-bit-ints/125280)

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**Author:** [@lntricate](https://discourse.julialang.org/u/lntricate)\
**Replies:** 5\
**Last updated:** [January 27, 2025, 10:42pm UTC](https://discourse.julialang.org/t/packing-and-unpacking-an-array-of-n-bit-ints/125280 "2025-01-27T22:42:52Z")

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Given an IO, I want to read N bits into each index of an Array{UInt64} and vice-versa: For example, the data \[0b0\_101\_100\_011\_010\_001\_000\_111\_110\_101\_100\_011\_010\_001\_000\_111\_110\_101\_100\_011\_010\_001, 0b00\_010\_001\_000\_111\_…

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## [Performant L-Shaped/PH Implementations in Julia?](https://discourse.julialang.org/t/performant-l-shaped-ph-implementations-in-julia/125276)

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**Author:** [@Sunash\_Sharma](https://discourse.julialang.org/u/Sunash_Sharma)\
**Replies:** 5\
**Last updated:** [January 27, 2025, 10:40pm UTC](https://discourse.julialang.org/t/performant-l-shaped-ph-implementations-in-julia/125276 "2025-01-27T22:40:44Z")

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Hi everyone, I want to solve a large two-stage stochastic optimization problem with a large number of scenarios (think around ~500 second stage scenarios and ~50-100 binary first stage decisions). As such, I need to use…

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## [Licensing Issues with Gurobi.jl on Cluster](https://discourse.julialang.org/t/licensing-issues-with-gurobi-jl-on-cluster/125270)

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**Author:** [@Sunash\_Sharma](https://discourse.julialang.org/u/Sunash_Sharma)\
**Replies:** 3\
**Last updated:** [January 27, 2025, 9:37pm UTC](https://discourse.julialang.org/t/licensing-issues-with-gurobi-jl-on-cluster/125270 "2025-01-27T21:37:45Z")

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TL;DR: Is there a way to use Gurobi.jl and distributed algorithms from StochasticPrograms.jl in a way that works on a cluster, given that StochasticPrograms.jl requires JuMP.jl version 1.2.1? Hi everyone, I’m planning …

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## [Gurobi.jl numerical trouble in optimal power flow](https://discourse.julialang.org/t/gurobi-jl-numerical-trouble-in-optimal-power-flow/125267)

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**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 5\
**Last updated:** [January 27, 2025, 9:29pm UTC](https://discourse.julialang.org/t/gurobi-jl-numerical-trouble-in-optimal-power-flow/125267 "2025-01-27T21:29:06Z")

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Hi. I am trying to model one of the ‘classic’ conic relaxations of the optimal powerflow model (see Branch Flow Model: Relaxations and Convexification—Part I) The problem I am running into is that depending on the loads…

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## [Solving AX=B with a matrix B of right-hand sides](https://discourse.julialang.org/t/solving-ax-b-with-a-matrix-b-of-right-hand-sides/125282)

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**Author:** [@B4rtel](https://discourse.julialang.org/u/B4rtel)\
**Replies:** 1\
**Last updated:** [January 27, 2025, 9:12pm UTC](https://discourse.julialang.org/t/solving-ax-b-with-a-matrix-b-of-right-hand-sides/125282 "2025-01-27T21:12:19Z")

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Hi, is your answer also the same for the case AX=B i.e. when X and B are matrices instead of vectors?

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## [\`llvmcall\` error "llvmcall only supports intrinsic calls" for scalar integer intrinsics on Apple M2](https://discourse.julialang.org/t/llvmcall-error-llvmcall-only-supports-intrinsic-calls-for-scalar-integer-intrinsics-on-apple-m2/125278)

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**Author:** [@guille](https://discourse.julialang.org/u/guille)\
**Replies:** 2\
**Last updated:** [January 27, 2025, 8:37pm UTC](https://discourse.julialang.org/t/llvmcall-error-llvmcall-only-supports-intrinsic-calls-for-scalar-integer-intrinsics-on-apple-m2/125278 "2025-01-27T20:37:59Z")

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Hello all! I’m encountering a very strange issue using llvmcall on my Apple M2 Mac with Julia 1.11.3. Hoping someone might have some insights or suggestions. Problem: When I try to use llvmcall to call basic LLVM scal…

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## [How to get reference to the field of mutable struct](https://discourse.julialang.org/t/how-to-get-reference-to-the-field-of-mutable-struct/125222)

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**Author:** [@Pedro](https://discourse.julialang.org/u/Pedro)\
**Replies:** 5\
**Last updated:** [January 27, 2025, 7:27pm UTC](https://discourse.julialang.org/t/how-to-get-reference-to-the-field-of-mutable-struct/125222 "2025-01-27T19:27:27Z")

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How one can create the reference to the field of the instantiated mutable struct? Let’s say I have a mutable struct A defined as mutable struct A v1::Int v2::Float64 end and an instance of this structure a = A…

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## [Failing to pre-compile OrdinaryDiffEqDefault](https://discourse.julialang.org/t/failing-to-pre-compile-ordinarydiffeqdefault/125179)

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**Author:** [@lpz18](https://discourse.julialang.org/u/lpz18)\
**Replies:** 3\
**Last updated:** [January 27, 2025, 7:18pm UTC](https://discourse.julialang.org/t/failing-to-pre-compile-ordinarydiffeqdefault/125179 "2025-01-27T19:18:56Z")

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Essence of the problem: Can’t install OrdinaryDiffEq anymore More context: I was working in Pluto notebooks and for some reason I can no longer install DifferentialEquations. I isolated it to OrdinaryDiffEqDefault. I …

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## [ODE non autonomous interpolation needed](https://discourse.julialang.org/t/ode-non-autonomous-interpolation-needed/125175)

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**Author:** [@Marta\_Pardo\_Araujo](https://discourse.julialang.org/u/Marta_Pardo_Araujo)\
**Replies:** 15\
**Last updated:** [January 27, 2025, 6:36pm UTC](https://discourse.julialang.org/t/ode-non-autonomous-interpolation-needed/125175 "2025-01-27T18:36:49Z")

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I am trying to optimize my code where I integrate a system of non-autonomous ODEs. The problem is the interpolations that I am doing in order to have the value of a parameter at each time step needed by the integrator. …

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## [Using Automatic Differentiation with FinEtoolsFlexStructures.jl](https://discourse.julialang.org/t/using-automatic-differentiation-with-finetoolsflexstructures-jl/125198)

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**Author:** [@Edan\_Lazerson](https://discourse.julialang.org/u/Edan_Lazerson)\
**Replies:** 2\
**Last updated:** [January 27, 2025, 6:32pm UTC](https://discourse.julialang.org/t/using-automatic-differentiation-with-finetoolsflexstructures-jl/125198 "2025-01-27T18:32:30Z")

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Hello everyone, I am exploring the use of automatic differentiation (AD) with the FinEtoolsFlexStructures.jl package and would like to know if anyone has experience with this. Specifically, I aim to compute the derivati…

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## [Labels in pie charts in Makie](https://discourse.julialang.org/t/labels-in-pie-charts-in-makie/94088)

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**Author:** [@mpirke](https://discourse.julialang.org/u/mpirke)\
**Replies:** 8\
**Last updated:** [January 27, 2025, 5:07pm UTC](https://discourse.julialang.org/t/labels-in-pie-charts-in-makie/94088 "2025-01-27T17:07:28Z")

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Hi there! I was wondering how to put labels on a pie chart in Makie. Like in the example shown on the page. using CairoMakie data = \[36, 12, 68, 5, 42, 27\] colors = \[:yellow, :orange, :red, :blue, :purple, :green\] …

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## [About Finitely presented groups in Oscar.jl](https://discourse.julialang.org/t/about-finitely-presented-groups-in-oscar-jl/125268)

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**Author:** [@Hakan\_Kucuk](https://discourse.julialang.org/u/Hakan_Kucuk)\
**Replies:** 4\
**Last updated:** [January 27, 2025, 4:06pm UTC](https://discourse.julialang.org/t/about-finitely-presented-groups-in-oscar-jl/125268 "2025-01-27T16:06:50Z")

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Hello Julia community, I am new to programming, especially abstract programming. I find the Oscar.jl package quite powerful and successful, but I need your help in creating finite and abstract groups ( Finitely presented…

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## [Best way to store a dataset with specific structure](https://discourse.julialang.org/t/best-way-to-store-a-dataset-with-specific-structure/125238)

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**Author:** [@danieleavitabile](https://discourse.julialang.org/u/danieleavitabile)\
**Replies:** 7\
**Last updated:** [January 27, 2025, 2:53pm UTC](https://discourse.julialang.org/t/best-way-to-store-a-dataset-with-specific-structure/125238 "2025-01-27T14:53:39Z")

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I am new to Julia and I must store and access a weirdly shaped dataset, for which I would like to ask your advice. It’s not very easy to explain what I must do. I must store in a variable, let say A, a collection of poi…

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## [ForwardDiff.jacobian failed to differentiate a code and gives a wrong result](https://discourse.julialang.org/t/forwarddiff-jacobian-failed-to-differentiate-a-code-and-gives-a-wrong-result/125225)

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**Author:** [@fduchenne](https://discourse.julialang.org/u/fduchenne)\
**Replies:** 8\
**Last updated:** [January 27, 2025, 2:35pm UTC](https://discourse.julialang.org/t/forwarddiff-jacobian-failed-to-differentiate-a-code-and-gives-a-wrong-result/125225 "2025-01-27T14:35:06Z")

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Dear Julia users, I have a complex ODE systems in which I use Gaussian overlaps, and I obtain wrong results when I estimate the Jaccobian of my ODE system using ForwardDiff.jacobian. I get a diagonal matrix, with zero f…

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## [Modeling Toolkit - parameters type conversion issue](https://discourse.julialang.org/t/modeling-toolkit-parameters-type-conversion-issue/125255)

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**Author:** [@NinaOmejc](https://discourse.julialang.org/u/NinaOmejc)\
**Replies:** 0\
**Last updated:** [January 27, 2025, 10:58am UTC](https://discourse.julialang.org/t/modeling-toolkit-parameters-type-conversion-issue/125255 "2025-01-27T10:58:12Z")

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I am trying to optimize my code and remove types Any. However, I am stuck with one within Modeling Toolkit. The code below shows the problem. When calling System function, sometimes I get parameters of type “Vector{Num}”…

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## [Order for finite elements when using Gridap and Gmsh](https://discourse.julialang.org/t/order-for-finite-elements-when-using-gridap-and-gmsh/125094)

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**Author:** [@mikeliux](https://discourse.julialang.org/u/mikeliux)\
**Replies:** 9\
**Last updated:** [January 27, 2025, 8:22am UTC](https://discourse.julialang.org/t/order-for-finite-elements-when-using-gridap-and-gmsh/125094 "2025-01-27T08:22:18Z")

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I am experimenting with Gridap package for solving partial differential equations (PDEs) in Julia. I am creating my meshes with GMSH, using the API provided by the Gmsh package in Julia. I save them as \*.msh files, and t…

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## [Package for Non-Parametric Multivariate Discrete Distributions](https://discourse.julialang.org/t/package-for-non-parametric-multivariate-discrete-distributions/125046)

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**Author:** [@bmit](https://discourse.julialang.org/u/bmit)\
**Replies:** 3\
**Last updated:** [January 27, 2025, 6:48am UTC](https://discourse.julialang.org/t/package-for-non-parametric-multivariate-discrete-distributions/125046 "2025-01-27T06:48:29Z")

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I’m looking for a package that implements tools for working with non-parametric multivariate discrete distributions. Ideally, this would look something like a Multivariate version of DiscreteNonParametric in Distribution…

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## [Tools to help catch use of uninitialized memory?](https://discourse.julialang.org/t/tools-to-help-catch-use-of-uninitialized-memory/124231)

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**Author:** [@nhz2](https://discourse.julialang.org/u/nhz2)\
**Replies:** 6\
**Last updated:** [January 26, 2025, 10:58pm UTC](https://discourse.julialang.org/t/tools-to-help-catch-use-of-uninitialized-memory/124231 "2025-01-26T22:58:55Z")

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It is easy to accidentally read from uninitialized memory after using resize! to grow a vector. Is there an equivalent of the memory sanitizer in C or any other tools for catching this when testing?

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