# Latest

**URL:** https://discourse.julialang.org/latest.md?page=564

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

**Page:** 565

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## [MethodError: no method matching zero(::Type{Vector{AffExpr}})](https://discourse.julialang.org/t/methoderror-no-method-matching-zero-type-vector-affexpr/105639)

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**Author:** [@Kaiming\_Zhang](https://discourse.julialang.org/u/Kaiming_Zhang)\
**Replies:** 5\
**Last updated:** [November 1, 2023, 7:47am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-zero-type-vector-affexpr/105639 "2023-11-01T07:47:19Z")

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I met a method error when running code in Julia 1.9. The code was written in Julia 1.1. How should I modify the code so that it can work? { "name": "MethodError", "message": "MethodError: no method matching zero(::Typ…

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## [Could not load library "libGR.dll"](https://discourse.julialang.org/t/could-not-load-library-libgr-dll/105644)

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**Author:** [@jameshu](https://discourse.julialang.org/u/jameshu)\
**Replies:** 0\
**Last updated:** [November 1, 2023, 7:20am UTC](https://discourse.julialang.org/t/could-not-load-library-libgr-dll/105644 "2023-11-01T07:20:09Z")

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The Julia-1.9.3 environment is good to run, “Plots.GRBackend()” displayed. But in the Jupyter notebook when running “Plots.Plot” function, the following errors are found as could not load library “libGR.dll” The spe…

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## [Formating decimal separator in xticks when plotting with PlotlyJS](https://discourse.julialang.org/t/formating-decimal-separator-in-xticks-when-plotting-with-plotlyjs/105641)

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**Author:** [@nnguyengiatan](https://discourse.julialang.org/u/nnguyengiatan)\
**Replies:** 1\
**Last updated:** [November 1, 2023, 5:59am UTC](https://discourse.julialang.org/t/formating-decimal-separator-in-xticks-when-plotting-with-plotlyjs/105641 "2023-11-01T05:59:25Z")

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Hi all, I have the dataset as follow: df = DataFrame( kvkt = \[ "Service", "Service", "Service", "Service", "Service", "Manufacturing", "Manufacturing", "Manufacturing", "Manufacturing", "Manufacturin…

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## [Epidemic Modeling with Scientific Machine Learning Postdoc at Sandia National Labs](https://discourse.julialang.org/t/epidemic-modeling-with-scientific-machine-learning-postdoc-at-sandia-national-labs/105640)

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**Author:** [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Replies:** 0\
**Last updated:** [November 1, 2023, 4:04am UTC](https://discourse.julialang.org/t/epidemic-modeling-with-scientific-machine-learning-postdoc-at-sandia-national-labs/105640 "2023-11-01T04:04:02Z")

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Posting for a collegue with whom the MIT Julia Lab actively collaborates with. The project is around learning universal differential equation representation of generation behavior from agent-based models. (This is actual…

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## [Fitting a multiple input Flux.jl model with learning networks in MLJ.jl](https://discourse.julialang.org/t/fitting-a-multiple-input-flux-jl-model-with-learning-networks-in-mlj-jl/105597)

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**Author:** [@boutor2](https://discourse.julialang.org/u/boutor2)\
**Replies:** 4\
**Last updated:** [November 1, 2023, 3:54am UTC](https://discourse.julialang.org/t/fitting-a-multiple-input-flux-jl-model-with-learning-networks-in-mlj-jl/105597 "2023-11-01T03:54:25Z")

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Hey there, I have tried to use MLJ.jl to fit a Flux model that takes in multiple inputs. While Flux.jl documentation demonstrates how to build such a model, I unfortunately cannot make it work within MLJ. Here is a MWE,…

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## [Longitudinal data plotting](https://discourse.julialang.org/t/longitudinal-data-plotting/105629)

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**Author:** [@Huputus](https://discourse.julialang.org/u/Huputus)\
**Replies:** 5\
**Last updated:** [October 31, 2023, 8:45pm UTC](https://discourse.julialang.org/t/longitudinal-data-plotting/105629 "2023-10-31T20:45:10Z")

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Hello people, I’m trying to plot longitudinal data that includes columns “ID”, “Time” and “Weight”. When I try to plot it with command plot(df.Time, df.Weight) it creates one line that goes back and forth. So how I can …

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## [Nonlinear constraints in SDDP](https://discourse.julialang.org/t/nonlinear-constraints-in-sddp/105626)

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**Author:** [@Sorooshsa](https://discourse.julialang.org/u/Sorooshsa)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 8:14pm UTC](https://discourse.julialang.org/t/nonlinear-constraints-in-sddp/105626 "2023-10-31T20:14:53Z")

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Hi, I have read the similar topics here: But my case is a bit different. I have a constraint with this formula: gen \<= efficiency\*water\_discharged gen is a continuous control variable, efficiency is a continuous s…

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## [Reconciling dynamic multimethod dispatch, parametric types and static compilation](https://discourse.julialang.org/t/reconciling-dynamic-multimethod-dispatch-parametric-types-and-static-compilation/105631)

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**Author:** [@ToucheSir](https://discourse.julialang.org/u/ToucheSir)\
**Replies:** 0\
**Last updated:** [October 31, 2023, 8:14pm UTC](https://discourse.julialang.org/t/reconciling-dynamic-multimethod-dispatch-parametric-types-and-static-compilation/105631 "2023-10-31T20:14:28Z")

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This is a spin-off from Roadmap for small binaries - #99 by thautwarm. My impression is that no language has managed to crack all three of these things, but it would be great if those who understand this design space bet…

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## [Feasibility of adding multiple inheritance to Julia](https://discourse.julialang.org/t/feasibility-of-adding-multiple-inheritance-to-julia/105382)

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**Author:** [@CameronBieganek](https://discourse.julialang.org/u/CameronBieganek)\
**Replies:** 36\
**Last updated:** [October 31, 2023, 6:03pm UTC](https://discourse.julialang.org/t/feasibility-of-adding-multiple-inheritance-to-julia/105382 "2023-10-31T18:03:11Z")

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The topic of interfaces came up again in one of the correctness threads. My minimally informed opinion is that the best solution would be to add multiple inheritance to the language. How feasible would it be to add mult…

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## [DataViewer.jl supported data file formats](https://discourse.julialang.org/t/dataviewer-jl-supported-data-file-formats/105569)

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**Author:** [@rajmac](https://discourse.julialang.org/u/rajmac)\
**Replies:** 15\
**Last updated:** [October 31, 2023, 6:00pm UTC](https://discourse.julialang.org/t/dataviewer-jl-supported-data-file-formats/105569 "2023-10-31T18:00:56Z")

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I was interested in the recent post on DataViewer.jl and wondered if it could be used with csv files or whether it requires hf5/jdl2/json datafiles?

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## [How to get numerator and denominator](https://discourse.julialang.org/t/how-to-get-numerator-and-denominator/105623)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 2\
**Last updated:** [October 31, 2023, 5:31pm UTC](https://discourse.julialang.org/t/how-to-get-numerator-and-denominator/105623 "2023-10-31T17:31:56Z")

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I need to do a lot of symbolic math processing these days. First question: How can a spit an expression in nominator and denominator? using Symbolics @variables R a b c d y = (2a+3b)/(4R - 3d) # den= # num=

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## [\[ANN\] OSMToolset.jl: A package to extract point-of-interest from maps and building walkability indexes](https://discourse.julialang.org/t/ann-osmtoolset-jl-a-package-to-extract-point-of-interest-from-maps-and-building-walkability-indexes/105622)

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**Author:** [@pszufe](https://discourse.julialang.org/u/pszufe)\
**Replies:** 0\
**Last updated:** [October 31, 2023, 5:14pm UTC](https://discourse.julialang.org/t/ann-osmtoolset-jl-a-package-to-extract-point-of-interest-from-maps-and-building-walkability-indexes/105622 "2023-10-31T17:14:53Z")

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Maps provided by the OpenStreetMap project contain very detailed information about schools, businesses, shops, restaurants, cafes, parking spaces, hospitals etc. With this tool you get an efficient, customizable API for …

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## [Good Julia function / algorithm idea to find the nearest node to a given point location based on some given road network (for example, open street map data)?](https://discourse.julialang.org/t/good-julia-function-algorithm-idea-to-find-the-nearest-node-to-a-given-point-location-based-on-some-given-road-network-for-example-open-street-map-data/22787)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 12\
**Last updated:** [October 31, 2023, 4:55pm UTC](https://discourse.julialang.org/t/good-julia-function-algorithm-idea-to-find-the-nearest-node-to-a-given-point-location-based-on-some-given-road-network-for-example-open-street-map-data/22787 "2023-10-31T16:55:16Z")

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Hello. In python, we have the nice function to get the nearest node to a given point location using the osmnx package as the following. import osmnx as ox ox.config(log\_console=True, use\_cache=True) G = ox.graph\_from…

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## [Is there a built-in command to weave and tangle current file in Julia in VS Code?](https://discourse.julialang.org/t/is-there-a-built-in-command-to-weave-and-tangle-current-file-in-julia-in-vs-code/105564)

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**Author:** [@homocomputeris](https://discourse.julialang.org/u/homocomputeris)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 4:03pm UTC](https://discourse.julialang.org/t/is-there-a-built-in-command-to-weave-and-tangle-current-file-in-julia-in-vs-code/105564 "2023-10-31T16:03:28Z")

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Is there a palette command in Julia in VS Code to weave and tange the current document? Or should one always run a script like this one? using Weave filename = normpath("./", "file.jmd") weave(filename; doctype="md2pdf"…

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## [Any package or provision to suggest alternative/fast code](https://discourse.julialang.org/t/any-package-or-provision-to-suggest-alternative-fast-code/105610)

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**Author:** [@VinodV](https://discourse.julialang.org/u/VinodV)\
**Replies:** 4\
**Last updated:** [October 31, 2023, 3:56pm UTC](https://discourse.julialang.org/t/any-package-or-provision-to-suggest-alternative-fast-code/105610 "2023-10-31T15:56:38Z")

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Suppose I have written a piece of code to check whether a string say “malayalam” is a palindrome. s = "malayalam" s == reverse(a) . An alternative is s == s\[end:-1:1\]. Is there a package or provision to suggest alter…

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## [Documenter error \[:cross\_references\]](https://discourse.julialang.org/t/documenter-error-cross-references/105533)

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**Author:** [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Replies:** 15\
**Last updated:** [October 31, 2023, 4:01pm UTC](https://discourse.julialang.org/t/documenter-error-cross-references/105533 "2023-10-31T16:01:24Z")

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I’d try to add a list of units and constants to Unitful - s. issue 623 (filed by @rafaqz). AFAIU currently the only way to find the symbol used is to look into the source code of pkgdefaults.jl The references are to be …

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## [How To Properly Use Unitful](https://discourse.julialang.org/t/how-to-properly-use-unitful/40295)

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**Author:** [@acdupont](https://discourse.julialang.org/u/acdupont)\
**Replies:** 13\
**Last updated:** [October 31, 2023, 2:58pm UTC](https://discourse.julialang.org/t/how-to-properly-use-unitful/40295 "2023-10-31T14:58:36Z")

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I’m using Unitful for the first time and would like direction on the proper way to use it. For my use case, I am creating a struct that I would like to store a specific unit because the value is being passed to such thin…

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## [Symbolics.jl problem trying to use solve\_for](https://discourse.julialang.org/t/symbolics-jl-problem-trying-to-use-solve-for/105319)

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**Author:** [@Mark\_Nahabedian](https://discourse.julialang.org/u/Mark_Nahabedian)\
**Replies:** 4\
**Last updated:** [October 31, 2023, 2:12pm UTC](https://discourse.julialang.org/t/symbolics-jl-problem-trying-to-use-solve-for/105319 "2023-10-31T14:12:33Z")

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I’m learning how to use Symbolcs.jl. My current work involves lines and vectors in three dimensional space. At the suggestion of, I think Shash, at a CAJUN about a month ago, since the Symbolics variables as introduced…

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## [How do I retain model parameters while freezing layers with Lux.jl](https://discourse.julialang.org/t/how-do-i-retain-model-parameters-while-freezing-layers-with-lux-jl/105558)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 1:52pm UTC](https://discourse.julialang.org/t/how-do-i-retain-model-parameters-while-freezing-layers-with-lux-jl/105558 "2023-10-31T13:52:28Z")

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I am very interested in the example given in the doc Freezing Model Parameters | LuxDL Docs. However, in that example, the parameters are obtained from ps, st = Lux.setup(rng, model\_frozen) I find there is no convenien…

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## [What is the correction factor for weighted variance](https://discourse.julialang.org/t/what-is-the-correction-factor-for-weighted-variance/105615)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 1:26pm UTC](https://discourse.julialang.org/t/what-is-the-correction-factor-for-weighted-variance/105615 "2023-10-31T13:26:32Z")

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Hi all, What is the formula for the correction factor for a weighted variance? Example: using StatsBase v = \[1,2,3\] p = \[.3,.5,.2\] std(v, ProbabilityWeights(p); corrected=true) Thanks!

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## [Implementation of the Lagrangian formalism using Julia](https://discourse.julialang.org/t/implementation-of-the-lagrangian-formalism-using-julia/89502)

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**Author:** [@Sh\_166](https://discourse.julialang.org/u/Sh_166)\
**Replies:** 14\
**Last updated:** [October 31, 2023, 11:57am UTC](https://discourse.julialang.org/t/implementation-of-the-lagrangian-formalism-using-julia/89502 "2023-10-31T11:57:26Z")

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Hi, I am a newcomer to Julia and I am specifically interested in applying Julia to physics problems. I have already worked through differential equations and plotting and stuff, and I am quite drawn by the language and h…

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## [Storing and accessing large jagged array with julia](https://discourse.julialang.org/t/storing-and-accessing-large-jagged-array-with-julia/45973)

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**Author:** [@Luapulu](https://discourse.julialang.org/u/Luapulu)\
**Replies:** 33\
**Last updated:** [October 31, 2023, 11:10am UTC](https://discourse.julialang.org/t/storing-and-accessing-large-jagged-array-with-julia/45973 "2023-10-31T11:10:50Z")

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I have a bunch of data, currently stored in 2000 seperate .csv files. Each file countains thousands of events, where each event starts with three numbers, one of which specifies the length of the event. All following row…

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## [Correct implementation of CuArray's slicing operations](https://discourse.julialang.org/t/correct-implementation-of-cuarrays-slicing-operations/90600)

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**Author:** [@FujiwaraTakumiEH](https://discourse.julialang.org/u/FujiwaraTakumiEH)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 10:29am UTC](https://discourse.julialang.org/t/correct-implementation-of-cuarrays-slicing-operations/90600 "2023-10-31T10:29:10Z")

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Hello, sometimes I need slicing operations on CuArray. I would like to know the correct (and efficient) way to achieve this. I made 4 benchmarks: Datasets: using BenchmarkTools using CUDA CUDA.allowscalar(true) # size o…

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## [DifferentialEquations Package](https://discourse.julialang.org/t/differentialequations-package/105599)

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**Author:** [@Andrej\_Ranisavljevic](https://discourse.julialang.org/u/Andrej_Ranisavljevic)\
**Replies:** 2\
**Last updated:** [October 31, 2023, 10:14am UTC](https://discourse.julialang.org/t/differentialequations-package/105599 "2023-10-31T10:14:24Z")

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Has anyone encountered errors while precompiling DifferentialEquations package in julia v1.9.3 release? For some reason i can’t manage to install it and get “Failed to precompile” error everytime. I have tried to delet…

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## [Unpacking of variables that do not exist](https://discourse.julialang.org/t/unpacking-of-variables-that-do-not-exist/105575)

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**Author:** [@johannesnauta](https://discourse.julialang.org/u/johannesnauta)\
**Replies:** 11\
**Last updated:** [October 31, 2023, 9:08am UTC](https://discourse.julialang.org/t/unpacking-of-variables-that-do-not-exist/105575 "2023-10-31T09:08:46Z")

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I am trying to optimise Catalyst code by omitting many reactions as their rates will, eventually, be put to zero. Briefly, I am considering systems of which many possible reactions will have a rate of 0. To avoid creatin…

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## [Where does this allocation pattern come from?](https://discourse.julialang.org/t/where-does-this-allocation-pattern-come-from/105606)

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**Author:** [@jw3126](https://discourse.julialang.org/u/jw3126)\
**Replies:** 3\
**Last updated:** [October 31, 2023, 9:07am UTC](https://discourse.julialang.org/t/where-does-this-allocation-pattern-come-from/105606 "2023-10-31T09:07:45Z")

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When I execute the following code, I get some interesting pattern: x = collect(1:1000) x\[1\] @showtime x\[511\] @showtime x\[511\] @showtime x\[511\] @showtime x\[512\] @showtime x\[512\] @showtime x\[512\] @showtime x\[511\] @showtim…

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## [Missing precision in the solution of combinations of ODE and jump processes using DifferentialEquations.jl and JumpProcesses.jl](https://discourse.julialang.org/t/missing-precision-in-the-solution-of-combinations-of-ode-and-jump-processes-using-differentialequations-jl-and-jumpprocesses-jl/105370)

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**Author:** [@VincentW](https://discourse.julialang.org/u/VincentW)\
**Replies:** 11\
**Last updated:** [October 31, 2023, 8:58am UTC](https://discourse.julialang.org/t/missing-precision-in-the-solution-of-combinations-of-ode-and-jump-processes-using-differentialequations-jl-and-jumpprocesses-jl/105370 "2023-10-31T08:58:48Z")

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Hey everyone, For a toy model, I tried to simulate an ODE together with a jump process, which jump rate at a certain time is dependent on the ODE at that time. (Motivated by the growth of a tumor and a death process, wh…

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## [MPI/Distributed linear system solver?](https://discourse.julialang.org/t/mpi-distributed-linear-system-solver/105355)

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**Author:** [@Ribeiro](https://discourse.julialang.org/u/Ribeiro)\
**Replies:** 20\
**Last updated:** [October 26, 2023, 9:00pm UTC](https://discourse.julialang.org/t/mpi-distributed-linear-system-solver/105355 "2023-10-26T21:00:11Z")

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Hi, folks. Is there a well established way to solve a linear system (normal, fully populated, Ax=b) across several nodes with Julia? Using MPI or something. I looked around and couldn’t find anything. Thanks!

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## [Help find best approach to streaming data on raspberry pi](https://discourse.julialang.org/t/help-find-best-approach-to-streaming-data-on-raspberry-pi/105130)

<div class="topic-metadata">

**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 16\
**Last updated:** [October 31, 2023, 5:47am UTC](https://discourse.julialang.org/t/help-find-best-approach-to-streaming-data-on-raspberry-pi/105130 "2023-10-31T05:47:22Z")

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I am trying to do some complicated asynchronous and preferably multiheaded operations on a Raspberry Pi. I have some ideas, but could really use some pointers on how to tackle problem. I will outline the approached I hav…

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## [Accessing a ComponentArray's fields in a type-stable manner](https://discourse.julialang.org/t/accessing-a-componentarrays-fields-in-a-type-stable-manner/103832)

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**Author:** [@Bizzi](https://discourse.julialang.org/u/Bizzi)\
**Replies:** 2\
**Last updated:** [October 31, 2023, 3:53am UTC](https://discourse.julialang.org/t/accessing-a-componentarrays-fields-in-a-type-stable-manner/103832 "2023-10-31T03:53:15Z")

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I’m struggling with iterating over the named fields of a ComponentArray in a compiler-friendly way. Take the following MWE, emulating some Neural Network: I create the nested structure layers, containing some weight …

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