# Latest

**URL:** https://discourse.julialang.org/latest.md?page=384

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

**Page:** 385

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## [Introduction to Physics Informed Neural Networks | A hands on, project based course](https://discourse.julialang.org/t/introduction-to-physics-informed-neural-networks-a-hands-on-project-based-course/115774)

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**Author:** [@VivekKmk](https://discourse.julialang.org/u/VivekKmk)\
**Replies:** 0\
**Last updated:** [June 17, 2024, 7:05pm UTC](https://discourse.julialang.org/t/introduction-to-physics-informed-neural-networks-a-hands-on-project-based-course/115774 "2024-06-17T19:05:53Z")

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YouTube Link: https://youtu.be/zjH8imO-UWo?si=JGICtlZrZ4y2UGf5 Do you like 3Blue1Brown videos? Would you like to watch a 3Blue1Brown style video on Physics-informed Neural Networks? Check out the video below created in …

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## [Simple transformation of a dataframe with grouped data](https://discourse.julialang.org/t/simple-transformation-of-a-dataframe-with-grouped-data/115660)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 4\
**Last updated:** [June 17, 2024, 6:09pm UTC](https://discourse.julialang.org/t/simple-transformation-of-a-dataframe-with-grouped-data/115660 "2024-06-17T18:09:11Z")

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I am trying to transpose this R script to Julia without success: library(dplyr) culture \<- tibble( ind = c(1, 1, 1, 2, 2, 2), year = c(2015, 2015, 2015, 2016, 2016, 2016), value = c(10, 20, 30, 26, 34, 67) ) cul…

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## [Environment activation using distributed](https://discourse.julialang.org/t/environment-activation-using-distributed/115773)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 0\
**Last updated:** [June 17, 2024, 5:53pm UTC](https://discourse.julialang.org/t/environment-activation-using-distributed/115773 "2024-06-17T17:53:28Z")

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Is it normal for the environment activation to take more than 10 minutes using @everywhere? In my case, all processes are on the same machine. They all activate the same environment. When doing this in an interactive …

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## [Which concepts known from Python programming are useful in understanding Julia and which are not?](https://discourse.julialang.org/t/which-concepts-known-from-python-programming-are-useful-in-understanding-julia-and-which-are-not/115460)

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**Author:** [@oOosys](https://discourse.julialang.org/u/oOosys)\
**Replies:** 52\
**Last updated:** [June 17, 2024, 4:53pm UTC](https://discourse.julialang.org/t/which-concepts-known-from-python-programming-are-useful-in-understanding-julia-and-which-are-not/115460 "2024-06-17T16:53:20Z")

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Are there concepts ingrained by 30 years of using Pyhon in my brain which I need to throw away and get rid of because they will lead to issues with understanding how to read and write Julia code (except zero-based indexi…

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## [Enzyme Cuda dynamic memory](https://discourse.julialang.org/t/enzyme-cuda-dynamic-memory/111063)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 12\
**Last updated:** [June 17, 2024, 3:56pm UTC](https://discourse.julialang.org/t/enzyme-cuda-dynamic-memory/111063 "2024-06-17T15:56:18Z")

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Hello I am trying to use enzyme with dynamic shared memory but I get error that probably is related to the fact that I am trying to instantiate dynamic memory in not device code. However If not use it like that how to ma…

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## [Hybrid ODE with ContinuousCallback for models of changing sizes?](https://discourse.julialang.org/t/hybrid-ode-with-continuouscallback-for-models-of-changing-sizes/115198)

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**Author:** [@natalieisenberg](https://discourse.julialang.org/u/natalieisenberg)\
**Replies:** 25\
**Last updated:** [June 17, 2024, 3:39pm UTC](https://discourse.julialang.org/t/hybrid-ode-with-continuouscallback-for-models-of-changing-sizes/115198 "2024-06-17T15:39:24Z")

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I am solving a system of ODEs with a ContinuousCallback where once a condition!() is met, certain members of the state vector are removed (i.e., elements disappear during simulation). I would like to solve this system us…

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## [Reading multiple files and also one file containg limits to read other file's content upto](https://discourse.julialang.org/t/reading-multiple-files-and-also-one-file-containg-limits-to-read-other-files-content-upto/115060)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 8\
**Last updated:** [June 17, 2024, 3:32pm UTC](https://discourse.julialang.org/t/reading-multiple-files-and-also-one-file-containg-limits-to-read-other-files-content-upto/115060 "2024-06-17T15:32:42Z")

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I have python code like: from pyfiles import \* runname='./' #define start dir and file, uncomment below sane = 1#0 for MAD98, 1 for SANE00 if sane == 1: inputfile=runname+'sane00.athinput' datafile='sane00.prim…

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## [ForwardDiff gradient iterated quadqk](https://discourse.julialang.org/t/forwarddiff-gradient-iterated-quadqk/115735)

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**Author:** [@Domenico\_Lahaye](https://discourse.julialang.org/u/Domenico_Lahaye)\
**Replies:** 9\
**Last updated:** [June 17, 2024, 2:37pm UTC](https://discourse.julialang.org/t/forwarddiff-gradient-iterated-quadqk/115735 "2024-06-17T14:37:47Z")

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Not sure about limitation (if any) of usage of ForwardDiff and quadgk. See MWE below. # define the mesh with N elements e\_k = \[x\_k, x\_{k+1}\] for 1 \<= k \<= N # the mesh contains N+1 nodes of which N-1 internal and 2 (le…

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## [Flux chain type unstable when broadcasting inside gradient](https://discourse.julialang.org/t/flux-chain-type-unstable-when-broadcasting-inside-gradient/115741)

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**Author:** [@filchristou](https://discourse.julialang.org/u/filchristou)\
**Replies:** 2\
**Last updated:** [June 17, 2024, 2:19pm UTC](https://discourse.julialang.org/t/flux-chain-type-unstable-when-broadcasting-inside-gradient/115741 "2024-06-17T14:19:13Z")

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I’ve been fighting for a couple of days to get my Flux/Zygote autodiff code type stable. I am not sure what’s the problem, but coming up with a MWE, it looks like broadcasting Flux.Chain is problematic ? using Flux, Zy…

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## [How to convert contractions from TensorOperations to ITensor?](https://discourse.julialang.org/t/how-to-convert-contractions-from-tensoroperations-to-itensor/115750)

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**Author:** [@Uranium238](https://discourse.julialang.org/u/Uranium238)\
**Replies:** 1\
**Last updated:** [June 17, 2024, 2:16pm UTC](https://discourse.julialang.org/t/how-to-convert-contractions-from-tensoroperations-to-itensor/115750 "2024-06-17T14:16:58Z")

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I am trying to write a code for an iterative solver of a set of non linear equations. Doing this needs computation of a lot of Tensor Contractions which I had been doing using TensorOperations.jl . My code is running fin…

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## [InfiniteOpt/supports violate the domain bounds](https://discourse.julialang.org/t/infiniteopt-supports-violate-the-domain-bounds/115751)

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**Author:** [@blob](https://discourse.julialang.org/u/blob)\
**Replies:** 1\
**Last updated:** [June 17, 2024, 2:04pm UTC](https://discourse.julialang.org/t/infiniteopt-supports-violate-the-domain-bounds/115751 "2024-06-17T14:04:26Z")

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I want to solve a problem with randomly generated bounds using InfiniteOpt. However, if I don’t specify the number of supports for the parameter, I get an error: If I specify the number of supports, the problem is so…

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## [FINAL DAY: Please complete the Julia User & Developer Survey TODAY!](https://discourse.julialang.org/t/final-day-please-complete-the-julia-user-developer-survey-today/115758)

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**Author:** [@ahclaster](https://discourse.julialang.org/u/ahclaster)\
**Replies:** 0\
**Last updated:** [June 17, 2024, 1:14pm UTC](https://discourse.julialang.org/t/final-day-please-complete-the-julia-user-developer-survey-today/115758 "2024-06-17T13:14:51Z")

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FINAL DAY: Click here to complete the Julia User & Developer Survey TODAY!

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## [Installer for Windows](https://discourse.julialang.org/t/installer-for-windows/115755)

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**Author:** [@Thomas\_Schweikle](https://discourse.julialang.org/u/Thomas_Schweikle)\
**Replies:** 1\
**Last updated:** [June 17, 2024, 1:06pm UTC](https://discourse.julialang.org/t/installer-for-windows/115755 "2024-06-17T13:06:47Z")

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Installing on Windows for all users does not work if no local administrator is available. The installer will always install for users. Why? Because the installer has to do elevation itself if the user calling the insta…

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## [Passing a structure with constructor on GPU](https://discourse.julialang.org/t/passing-a-structure-with-constructor-on-gpu/115596)

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**Author:** [@Baptiste\_Fabre](https://discourse.julialang.org/u/Baptiste_Fabre)\
**Replies:** 2\
**Last updated:** [June 17, 2024, 1:06pm UTC](https://discourse.julialang.org/t/passing-a-structure-with-constructor-on-gpu/115596 "2024-06-17T13:06:32Z")

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Dear all, I have a question about how to pass a structure built with a constructor on a GPU card. My structure is defined as struct FieldParams{T} I₀ :: T λ₀ :: T α :: T r :: T ω :: T E₀ :: T Up :: T T₀ :: T N…

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## [Allocations and time of running the same program twice are orders of magnitude larger than running them separately](https://discourse.julialang.org/t/allocations-and-time-of-running-the-same-program-twice-are-orders-of-magnitude-larger-than-running-them-separately/114078)

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**Author:** [@dieg0](https://discourse.julialang.org/u/dieg0)\
**Replies:** 11\
**Last updated:** [June 17, 2024, 12:58pm UTC](https://discourse.julialang.org/t/allocations-and-time-of-running-the-same-program-twice-are-orders-of-magnitude-larger-than-running-them-separately/114078 "2024-06-17T12:58:52Z")

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I am relatively new to Julia. I am building a code to optimize some objective function that is called many times. The most important intermediate step is computing the following function, called recover\_δ! which is a fix…

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## [Movie from data](https://discourse.julialang.org/t/movie-from-data/115739)

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**Author:** [@NaSi](https://discourse.julialang.org/u/NaSi)\
**Replies:** 4\
**Last updated:** [June 17, 2024, 12:05pm UTC](https://discourse.julialang.org/t/movie-from-data/115739 "2024-06-17T12:05:15Z")

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Hi there ! I am new on Julia, so I would appreciate your help. I have a data set called data : julia\> size(data) (4994, 50405) 4994 is the distance along an axis and 50405 is the time with : julia\> size(time\_test) …

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## [Find values on a plot with the mouse](https://discourse.julialang.org/t/find-values-on-a-plot-with-the-mouse/115743)

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**Author:** [@NaSi](https://discourse.julialang.org/u/NaSi)\
**Replies:** 1\
**Last updated:** [June 17, 2024, 11:31am UTC](https://discourse.julialang.org/t/find-values-on-a-plot-with-the-mouse/115743 "2024-06-17T11:31:10Z")

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Hello ! I am using GLMakie to vizualise some data : fig = Figure() ax1 = Axis(fig\[1,1\]) lines(space\_sampling,data\[:,100\]) I would like to be able to go on the plot and to find the values of coordinates for any point…

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## [Unstable ODE within Turing model](https://discourse.julialang.org/t/unstable-ode-within-turing-model/115419)

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**Author:** [@caesoma](https://discourse.julialang.org/u/caesoma)\
**Replies:** 8\
**Last updated:** [June 17, 2024, 10:18am UTC](https://discourse.julialang.org/t/unstable-ode-within-turing-model/115419 "2024-06-17T10:18:39Z")

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I have a fairly complicated ODE system I am using within Turing for HMC sampling. Sampling seems to work fine: traces and metrics look good in general. However, when I extract a few random samples from the chain and run …

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## [ParallelStencil @init\_parallel\_stencil Workflow](https://discourse.julialang.org/t/parallelstencil-init-parallel-stencil-workflow/115713)

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**Author:** [@jdm204](https://discourse.julialang.org/u/jdm204)\
**Replies:** 3\
**Last updated:** [June 17, 2024, 9:46am UTC](https://discourse.julialang.org/t/parallelstencil-init-parallel-stencil-workflow/115713 "2024-06-17T09:46:39Z")

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Hi, ParallelStencil is great, but I’ve ran into a development pain point and was wondering if anyone can guide me. Say I’m developing a package that exports a diffuse! function that calculates an iteration of diffusion …

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## [Save and load NeuralPDE model for postprocessing](https://discourse.julialang.org/t/save-and-load-neuralpde-model-for-postprocessing/114668)

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**Author:** [@PetrosStefanou](https://discourse.julialang.org/u/PetrosStefanou)\
**Replies:** 3\
**Last updated:** [June 17, 2024, 9:10am UTC](https://discourse.julialang.org/t/save-and-load-neuralpde-model-for-postprocessing/114668 "2024-06-17T09:10:43Z")

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Hi, I want to save a trained NeuralPDE model and then load it to some other script at a later time for analysis and post-processing. In this reply it is suggested to save the trained Lux parameters stored in res.u. I a…

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## [How to delete a variable from memory in Julia?](https://discourse.julialang.org/t/how-to-delete-a-variable-from-memory-in-julia/115649)

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**Author:** [@Uranium238](https://discourse.julialang.org/u/Uranium238)\
**Replies:** 12\
**Last updated:** [June 17, 2024, 8:26am UTC](https://discourse.julialang.org/t/how-to-delete-a-variable-from-memory-in-julia/115649 "2024-06-17T08:26:58Z")

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Below is a very memory and performance intensive part of my code which aims to a system of non-linear equations via tensor contractions. Performance and memory intensive codefunction calculate\_residual\_memeff(T2) # …

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## [Failed process: error while adding python cis library](https://discourse.julialang.org/t/failed-process-error-while-adding-python-cis-library/115551)

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**Author:** [@raman\_kumar](https://discourse.julialang.org/u/raman_kumar)\
**Replies:** 37\
**Last updated:** [June 17, 2024, 6:42am UTC](https://discourse.julialang.org/t/failed-process-error-while-adding-python-cis-library/115551 "2024-06-17T06:42:08Z")

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I want to add cis library which has api in python. using CondaPkg; CondaPkg.add("cis") @abraemer

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## [How do I define eltype for custom composite type?](https://discourse.julialang.org/t/how-do-i-define-eltype-for-custom-composite-type/115726)

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**Author:** [@vshesh](https://discourse.julialang.org/u/vshesh)\
**Replies:** 4\
**Last updated:** [June 17, 2024, 1:05am UTC](https://discourse.julialang.org/t/how-do-i-define-eltype-for-custom-composite-type/115726 "2024-06-17T01:05:09Z")

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I tried creating my own container type alias: Forest{Tree} = Union{\<: AbstractVector{\<: Tree}, \<: AbstractSet{\<: Tree}} I want to do, in essence: Base.eltype(::Type{Forest{T}}) where T = T julia\> eltype(Forest{Int})…

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## [Question about my Plots](https://discourse.julialang.org/t/question-about-my-plots/115638)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 2\
**Last updated:** [June 17, 2024, 12:13am UTC](https://discourse.julialang.org/t/question-about-my-plots/115638 "2024-06-17T00:13:50Z")

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julia\> using Plots \[ Info: Precompiling Plots \[91a5bcdd-55d7-5caf-9e0b-520d859cae80\] ERROR: LoadError: LoadError: InitError: could not load library “C:\\Users\\Administrator.julia\\artifacts\\2ef92b843c5dee978e2aaf8494e…

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## [Julia throws MethodError: no method matching, with CoolProp using NonlinearSystem](https://discourse.julialang.org/t/julia-throws-methoderror-no-method-matching-with-coolprop-using-nonlinearsystem/115721)

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**Author:** [@Bumlebi](https://discourse.julialang.org/u/Bumlebi)\
**Replies:** 3\
**Last updated:** [June 16, 2024, 10:12pm UTC](https://discourse.julialang.org/t/julia-throws-methoderror-no-method-matching-with-coolprop-using-nonlinearsystem/115721 "2024-06-16T22:12:00Z")

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Hi all, I’m trying to get Julia’s NonlinearSolve to play well with CoolProp. I am very new at Julia, coming from many years of Python, so I am still learning the ropes. This is the code that is giving me trouble: usin…

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## [Understanding display of equations and computation with Symbolics.jl](https://discourse.julialang.org/t/understanding-display-of-equations-and-computation-with-symbolics-jl/114558)

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**Author:** [@hatmatrix](https://discourse.julialang.org/u/hatmatrix)\
**Replies:** 2\
**Last updated:** [June 16, 2024, 9:47pm UTC](https://discourse.julialang.org/t/understanding-display-of-equations-and-computation-with-symbolics-jl/114558 "2024-06-16T21:47:35Z")

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I got from the documentation that you can use Symbolics.jl and Latexify.jl together to display your equations. However, what can be evaluated gets evaluated right away so in that sense not the same as sympy or Sympy.jl …

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## [Vector of vectors with floats: Type confusion](https://discourse.julialang.org/t/vector-of-vectors-with-floats-type-confusion/115707)

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**Author:** [@Santiago\_Lopez](https://discourse.julialang.org/u/Santiago_Lopez)\
**Replies:** 4\
**Last updated:** [June 16, 2024, 9:32pm UTC](https://discourse.julialang.org/t/vector-of-vectors-with-floats-type-confusion/115707 "2024-06-16T21:32:49Z")

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I have a vector of vectors vv. Each vector v in vv is of type Vector{Float32}: julia\> unique(typeof.(vv)) 1-element Vector{DataType}: Vector{Float32} (alias for Array{Float32, 1}) However, julia\> typeof(vv) Vector{Ve…

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## [Deserialization in a Module()](https://discourse.julialang.org/t/deserialization-in-a-module/115577)

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**Author:** [@ablaom](https://discourse.julialang.org/u/ablaom)\
**Replies:** 2\
**Last updated:** [June 16, 2024, 8:11pm UTC](https://discourse.julialang.org/t/deserialization-in-a-module/115577 "2024-06-16T20:11:35Z")

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I don’t understand why the code below errors: module TestMod MyMod = Module() Core.eval( MyMod, quote using Serialization f() = "hello" …

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## [\[ANN\] StringCases.jl](https://discourse.julialang.org/t/ann-stringcases-jl/115709)

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**Author:** [@acxz](https://discourse.julialang.org/u/acxz)\
**Replies:** 0\
**Last updated:** [June 16, 2024, 5:32am UTC](https://discourse.julialang.org/t/ann-stringcases-jl/115709 "2024-06-16T05:32:26Z")

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I’d like to announce a new string case package, GitHub - acxz/StringCases.jl: Define, validate, and convert string cases. A Julia package for string cases that allows users to define their own string case validate str…

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## [Using \`Enum\`s as indices](https://discourse.julialang.org/t/using-enum-s-as-indices/115718)

<div class="topic-metadata">

**Author:** [@sgaure](https://discourse.julialang.org/u/sgaure)\
**Replies:** 3\
**Last updated:** [June 16, 2024, 7:02pm UTC](https://discourse.julialang.org/t/using-enum-s-as-indices/115718 "2024-06-16T19:02:50Z")

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I’m using enum’s for some purposes. In particular for indexing arrays. It works fine, except for some types of broadcasting: a = \[zeros(10) for \_ in 1:4\]; b = \[zeros(10) for \_ in 1:4\]; @enum Count one=1 two three four …

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