# Latest

**URL:** https://discourse.julialang.org/latest.md?page=292

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

**Page:** 293

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## [DBSCAN clustering with Haversine metric](https://discourse.julialang.org/t/dbscan-clustering-with-haversine-metric/121685)

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**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 4\
**Last updated:** [October 24, 2024, 12:53pm UTC](https://discourse.julialang.org/t/dbscan-clustering-with-haversine-metric/121685 "2024-10-24T12:53:46Z")

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Hi there, I have an array of points (latitude, longitude) in radians and I am trying to use the package Clustering.jl to cluster my points. In the documentation it seems like a metric can be given, the default being: Eu…

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## [Haskell forum post argues that Commercial Haskell should go after Julia ( and Python) instead of Rust](https://discourse.julialang.org/t/haskell-forum-post-argues-that-commercial-haskell-should-go-after-julia-and-python-instead-of-rust/121526)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 4\
**Last updated:** [October 24, 2024, 12:25pm UTC](https://discourse.julialang.org/t/haskell-forum-post-argues-that-commercial-haskell-should-go-after-julia-and-python-instead-of-rust/121526 "2024-10-24T12:25:12Z")

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I find the post a pretty amusing read.

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## [How to put gif or mp4 file in Literate documentation page?](https://discourse.julialang.org/t/how-to-put-gif-or-mp4-file-in-literate-documentation-page/121468)

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**Author:** [@vladdez](https://discourse.julialang.org/u/vladdez)\
**Replies:** 1\
**Last updated:** [October 24, 2024, 9:31am UTC](https://discourse.julialang.org/t/how-to-put-gif-or-mp4-file-in-literate-documentation-page/121468 "2024-10-24T09:31:12Z")

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I want to attach gif or mp4 file on documentation page. My code is: # \`\`\`@raw html # \<video autoplay loop muted playsinline controls src="../../../assets/topoplot\_animation\_UM.gif" /\> # \`\`\` This is the page deployed: B…

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## [Photo Polymerisation Using Catalyst with constant Photon Species](https://discourse.julialang.org/t/photo-polymerisation-using-catalyst-with-constant-photon-species/121686)

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**Author:** [@Map3GOSM](https://discourse.julialang.org/u/Map3GOSM)\
**Replies:** 0\
**Last updated:** [October 24, 2024, 9:00am UTC](https://discourse.julialang.org/t/photo-polymerisation-using-catalyst-with-constant-photon-species/121686 "2024-10-24T09:00:41Z")

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Hi everyone, I am trying to set up a reaction network using Catalyst where one species remains at a constant value. I’m modelling a photo reaction and want to track the concentration of photons. In a simplified form, i…

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## [Recommended workflow and packages for computing a slope along a tramway track](https://discourse.julialang.org/t/recommended-workflow-and-packages-for-computing-a-slope-along-a-tramway-track/119975)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 39\
**Last updated:** [October 24, 2024, 9:00am UTC](https://discourse.julialang.org/t/recommended-workflow-and-packages-for-computing-a-slope-along-a-tramway-track/119975 "2024-10-24T09:00:37Z")

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I would like to ask for a recommendation on a workflow for computing a slope along a tramway track using Julia’s geo ecosystem (organizations JuliaEarth, JuliaGeo, …). The tramway tracks are obtained from OpenStreetMaps…

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## [Type inference difference in \`mapreduce(f, op, t)\` vs \`reduce(op, map(f, t))\`](https://discourse.julialang.org/t/type-inference-difference-in-mapreduce-f-op-t-vs-reduce-op-map-f-t/93265)

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**Author:** [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Replies:** 1\
**Last updated:** [October 24, 2024, 8:42am UTC](https://discourse.julialang.org/t/type-inference-difference-in-mapreduce-f-op-t-vs-reduce-op-map-f-t/93265 "2024-10-24T08:42:21Z")

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For tuples, it seems mapreduce has poorer type inference than map + reduce. julia\> using FillArrays, Infinities, InfiniteArrays, Test julia\> ax = Ones{Int}(InfiniteCardinal{0}()); julia\> y = (ax,ax); julia\> @inferred…

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## [Component-based model for N reactors connected to a tank](https://discourse.julialang.org/t/component-based-model-for-n-reactors-connected-to-a-tank/119536)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 9\
**Last updated:** [October 24, 2024, 8:29am UTC](https://discourse.julialang.org/t/component-based-model-for-n-reactors-connected-to-a-tank/119536 "2024-10-24T08:29:25Z")

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Say I’ve got 10 chemical reactors, which all flow into a single tank. The reactors all have different production rates for some species S. I’m interested in the concentration of S in the reactors and in the tank. I guess…

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## [Optimization problem that fails to converge](https://discourse.julialang.org/t/optimization-problem-that-fails-to-converge/121666)

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**Author:** [@Iforire](https://discourse.julialang.org/u/Iforire)\
**Replies:** 3\
**Last updated:** [October 24, 2024, 7:55am UTC](https://discourse.julialang.org/t/optimization-problem-that-fails-to-converge/121666 "2024-10-24T07:55:55Z")

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Hi all, I am very new to Julia and maths is quite old for me now, so I am struggling with my code. The thing is that I would like to find the best linear combination of six parameters that fits the seventh parameter. …

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## [What is the Proper Way To Do Interactive Inline Plots? (Workaround Found)](https://discourse.julialang.org/t/what-is-the-proper-way-to-do-interactive-inline-plots-workaround-found/121679)

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**Author:** [@tillfalko](https://discourse.julialang.org/u/tillfalko)\
**Replies:** 0\
**Last updated:** [October 24, 2024, 7:00am UTC](https://discourse.julialang.org/t/what-is-the-proper-way-to-do-interactive-inline-plots-workaround-found/121679 "2024-10-24T07:00:25Z")

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What I’m looking for I’m looking for a non-janky way to create interactive inline plots in a VSCode Notebook using either Plots.jl or any Makie version. Workaround I have found a way to do it in Plots.jl, but it’s clear…

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## [Hit a few dead ends setting up a slider server. Easy(ish) solution possible?](https://discourse.julialang.org/t/hit-a-few-dead-ends-setting-up-a-slider-server-easy-ish-solution-possible/118907)

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**Author:** [@sguis](https://discourse.julialang.org/u/sguis)\
**Replies:** 14\
**Last updated:** [October 24, 2024, 6:45am UTC](https://discourse.julialang.org/t/hit-a-few-dead-ends-setting-up-a-slider-server-easy-ish-solution-possible/118907 "2024-10-24T06:45:09Z")

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Hello everybody. Huge thanks and admiration for all the wonderful things coming out of the Julia and Pluto worlds. Astonishing :slight\_smile: I’m teaching calculus this semester and have been making Pluto notebooks to h…

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## [Who should own a package extension? Does it matter?](https://discourse.julialang.org/t/who-should-own-a-package-extension-does-it-matter/121668)

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**Author:** [@brainandforce](https://discourse.julialang.org/u/brainandforce)\
**Replies:** 5\
**Last updated:** [October 24, 2024, 5:57am UTC](https://discourse.julialang.org/t/who-should-own-a-package-extension-does-it-matter/121668 "2024-10-24T05:57:00Z")

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I want to ensure that my package, CliffordNumbers.jl, interoperates with Unitful.jl, and that parametric types dependent on both packages (like Quantity{\<:AbstractCliffordNumber}) have operations defined on them consiste…

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## [How to override defaults with u0 in solve](https://discourse.julialang.org/t/how-to-override-defaults-with-u0-in-solve/121629)

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**Author:** [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)\
**Replies:** 2\
**Last updated:** [October 24, 2024, 5:02am UTC](https://discourse.julialang.org/t/how-to-override-defaults-with-u0-in-solve/121629 "2024-10-24T05:02:41Z")

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I have an ODEProblem with a system with default values, and with a starting state prob.u0. I want to be able to solve this problem from an arbitrary starting state u0 to the next timestep using solve(prob, QNDF(); save\_s…

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## [Markdown in VSCode](https://discourse.julialang.org/t/markdown-in-vscode/121664)

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**Author:** [@uri](https://discourse.julialang.org/u/uri)\
**Replies:** 2\
**Last updated:** [October 24, 2024, 3:17am UTC](https://discourse.julialang.org/t/markdown-in-vscode/121664 "2024-10-24T03:17:48Z")

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is it possible to insert comments in a julia formatted as md. I’ve heard that something as my following example is possible, and when you hover the mouse over the md text it appears formated. """ # Simple Markdown Tit…

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## [Performance comparison of a custom gcd() function in Julia, C, and Rust](https://discourse.julialang.org/t/performance-comparison-of-a-custom-gcd-function-in-julia-c-and-rust/121665)

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**Author:** [@jbytecode](https://discourse.julialang.org/u/jbytecode)\
**Replies:** 7\
**Last updated:** [October 23, 2024, 10:58pm UTC](https://discourse.julialang.org/t/performance-comparison-of-a-custom-gcd-function-in-julia-c-and-rust/121665 "2024-10-23T22:58:53Z")

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Here is the naive implementation of the gcd (Greatest Common Divisor) in Julia: function mygcd(a::Int64, b::Int64)::Int64 if a == b return a elseif a \> b return mygcd(a-b, b) else return m…

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## [Sampling from a KDE object](https://discourse.julialang.org/t/sampling-from-a-kde-object/121604)

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**Author:** [@miguelborrero](https://discourse.julialang.org/u/miguelborrero)\
**Replies:** 4\
**Last updated:** [October 23, 2024, 8:54pm UTC](https://discourse.julialang.org/t/sampling-from-a-kde-object/121604 "2024-10-23T20:54:06Z")

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Hi there, I estimated the density for a variable of interest using the kde() function from KernelDensity.jl package. Is there not a built-in/efficient function that samples from this estimated density? Thanks a lot!

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## [Tuple{Vararg{T, N}} where N \>= 1](https://discourse.julialang.org/t/tuple-vararg-t-n-where-n-1/121644)

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**Author:** [@croberts](https://discourse.julialang.org/u/croberts)\
**Replies:** 9\
**Last updated:** [October 23, 2024, 7:35pm UTC](https://discourse.julialang.org/t/tuple-vararg-t-n-where-n-1/121644 "2024-10-23T19:35:39Z")

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It can be extremely convenient to dispatch on the types of arguments in a tuple, creating an alias for tuples of a type. However, a zero-length tuple will match a Vararg Tuple of any type, which can create issues with d…

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## [Cassette performance overhead](https://discourse.julialang.org/t/cassette-performance-overhead/121659)

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**Author:** [@jgarvin](https://discourse.julialang.org/u/jgarvin)\
**Replies:** 1\
**Last updated:** [October 23, 2024, 5:44pm UTC](https://discourse.julialang.org/t/cassette-performance-overhead/121659 "2024-10-23T17:44:04Z")

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I’ve been getting frustrated by some of the limitations around metaprogramming in Python and recently heard about Cassette. One thing that’s confusing to me without having a strong understanding of Julia yet is why Casse…

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## [Did i coded my pde correctly?](https://discourse.julialang.org/t/did-i-coded-my-pde-correctly/121661)

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**Author:** [@Shashi2\_Kumar](https://discourse.julialang.org/u/Shashi2_Kumar)\
**Replies:** 0\
**Last updated:** [October 23, 2024, 5:08pm UTC](https://discourse.julialang.org/t/did-i-coded-my-pde-correctly/121661 "2024-10-23T17:08:55Z")

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After many weeks of search for a pde solver for my elliptic pde i came across Julia. Found that it has a FNC package (FundamentalsNumericalComputation) that solves pde. I tried to encode my pde with boundary conditions a…

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## [Creating Parameters.jl struct samples using variable keywords](https://discourse.julialang.org/t/creating-parameters-jl-struct-samples-using-variable-keywords/121639)

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**Author:** [@JPool](https://discourse.julialang.org/u/JPool)\
**Replies:** 4\
**Last updated:** [October 23, 2024, 5:06pm UTC](https://discourse.julialang.org/t/creating-parameters-jl-struct-samples-using-variable-keywords/121639 "2024-10-23T17:06:13Z")

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Hi, I’m trying to make a function that takes in a default struct which holds parameters for my model. I want to be able to make a sample list where some properties are kept constant, and some are sampled using a sampling…

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## [Empty period problem - an exceptional case](https://discourse.julialang.org/t/empty-period-problem-an-exceptional-case/121655)

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**Author:** [@anon91151494](https://discourse.julialang.org/u/anon91151494)\
**Replies:** 2\
**Last updated:** [October 23, 2024, 4:58pm UTC](https://discourse.julialang.org/t/empty-period-problem-an-exceptional-case/121655 "2024-10-23T16:58:10Z")

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I have discovered a problem with the implementation of the Dates CompoundPeriod type. Here’s a simple REPL demo. julia\> using Dates julia\> ms0 = Millisecond(0) 0 milliseconds julia\> canonicalize(ms0) empty period As…

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## [Documenter.jl only updating dev section in my package](https://discourse.julialang.org/t/documenter-jl-only-updating-dev-section-in-my-package/121650)

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**Author:** [@Iddingsite](https://discourse.julialang.org/u/Iddingsite)\
**Replies:** 3\
**Last updated:** [October 23, 2024, 4:15pm UTC](https://discourse.julialang.org/t/documenter-jl-only-updating-dev-section-in-my-package/121650 "2024-10-23T16:15:27Z")

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Hi everyone, I have been developping a package for some time now, and I struggle to setup up the documentation correctly with Documenter.jl. Everything seems to be configured correctly, but only the dev part of the docu…

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## [Fast ways to check if an element is in a vector of vector of elements](https://discourse.julialang.org/t/fast-ways-to-check-if-an-element-is-in-a-vector-of-vector-of-elements/121598)

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**Author:** [@rakshith95](https://discourse.julialang.org/u/rakshith95)\
**Replies:** 20\
**Last updated:** [October 23, 2024, 3:42pm UTC](https://discourse.julialang.org/t/fast-ways-to-check-if-an-element-is-in-a-vector-of-vector-of-elements/121598 "2024-10-23T15:42:36Z")

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Hello , What would be the most efficient way to look for a number in a vector of vector of numbers? i.e. Data: t = \[ \[1,2,3\] , \[4,5,6\] , \[1,10,12\], \[1,4,5\] \] Input: 1 Output: 1,3,4 I could do something like findall…

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## [Status of Julia database libraries](https://discourse.julialang.org/t/status-of-julia-database-libraries/11877)

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**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 143\
**Last updated:** [October 23, 2024, 3:12pm UTC](https://discourse.julialang.org/t/status-of-julia-database-libraries/11877 "2024-10-23T15:12:27Z")

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TLDR; My experience with the DB access libraries has been overwhelmingly negative - I’m concerned that the Julia ecosystem is missing a huge foundational piece for success. Things don’t look any better as we’re moving to…

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## [Scalar indexing is disallowed - ODE solve using GPU](https://discourse.julialang.org/t/scalar-indexing-is-disallowed-ode-solve-using-gpu/121645)

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**Author:** [@agme2014](https://discourse.julialang.org/u/agme2014)\
**Replies:** 2\
**Last updated:** [October 23, 2024, 3:11pm UTC](https://discourse.julialang.org/t/scalar-indexing-is-disallowed-ode-solve-using-gpu/121645 "2024-10-23T15:11:27Z")

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Hi, I want to use NVIDIA GPU in my laptop to speed up Neural ODE computation. I started with testing out GPU on ODEs but I am getting the below error during the “solve” step : ERROR: Scalar indexing is disallowed. Invo…

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## [How to Update Non-Time-Dependent States in Mixed ODE Problems?](https://discourse.julialang.org/t/how-to-update-non-time-dependent-states-in-mixed-ode-problems/121594)

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**Author:** [@chooron](https://discourse.julialang.org/u/chooron)\
**Replies:** 11\
**Last updated:** [October 23, 2024, 3:07pm UTC](https://discourse.julialang.org/t/how-to-update-non-time-dependent-states-in-mixed-ode-problems/121594 "2024-10-23T15:07:58Z")

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Hello, I’d like to ask for your help. In an ODE problem, after I complete the calculations for a given time step ( t ), I need to update a certain state. This state is not time-dependent but is recalculated based on anot…

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## [Get base10 mantissa and exponent of real (eg Float64)](https://discourse.julialang.org/t/get-base10-mantissa-and-exponent-of-real-eg-float64/121529)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 11\
**Last updated:** [October 22, 2024, 8:54am UTC](https://discourse.julialang.org/t/get-base10-mantissa-and-exponent-of-real-eg-float64/121529 "2024-10-22T08:54:36Z")

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What would be the recommended way of getting the base 10 mantissa and exponent of a floating point number? Is there a package that does this? Or should I just reparse from printed representation, as in using Printf fu…

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## [Turning a stochastic simulator into a set of deterministic simulators by fixing the seed](https://discourse.julialang.org/t/turning-a-stochastic-simulator-into-a-set-of-deterministic-simulators-by-fixing-the-seed/121642)

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**Author:** [@weltenbummler](https://discourse.julialang.org/u/weltenbummler)\
**Replies:** 0\
**Last updated:** [October 23, 2024, 1:43pm UTC](https://discourse.julialang.org/t/turning-a-stochastic-simulator-into-a-set-of-deterministic-simulators-by-fixing-the-seed/121642 "2024-10-23T13:43:31Z")

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Hello all, I am given a stochastic simulator and would like to turn it into n deterministic simulators where each operates with a fixed seed. The simulators depend on some parameters that the user can specify. My quest…

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## [How to format or print a difference in two DateTime objects](https://discourse.julialang.org/t/how-to-format-or-print-a-difference-in-two-datetime-objects/121638)

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**Author:** [@anon91151494](https://discourse.julialang.org/u/anon91151494)\
**Replies:** 7\
**Last updated:** [October 23, 2024, 2:09pm UTC](https://discourse.julialang.org/t/how-to-format-or-print-a-difference-in-two-datetime-objects/121638 "2024-10-23T14:09:48Z")

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I want to print the following object, which is a difference between two DateTimes datetime\_diff = datetime2 - datetime1 The type of datetime\_diff appears to be Milliseconds. That means it can be printed, but produces t…

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## [Elegant handling of possibly-state-dependent parameters in physical simulation](https://discourse.julialang.org/t/elegant-handling-of-possibly-state-dependent-parameters-in-physical-simulation/121640)

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**Author:** [@Ickaser](https://discourse.julialang.org/u/Ickaser)\
**Replies:** 1\
**Last updated:** [October 23, 2024, 1:34pm UTC](https://discourse.julialang.org/t/elegant-handling-of-possibly-state-dependent-parameters-in-physical-simulation/121640 "2024-10-23T13:34:44Z")

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For a couple years now, I have been using OrdinaryDiffEq for developing a handful of models for describing the process of pharmaceutical lyophilization. The more time I spend, the more I learn about more aspects of Julia…

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## [Float64 error in plotting](https://discourse.julialang.org/t/float64-error-in-plotting/121603)

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**Author:** [@agme2014](https://discourse.julialang.org/u/agme2014)\
**Replies:** 3\
**Last updated:** [October 23, 2024, 1:34pm UTC](https://discourse.julialang.org/t/float64-error-in-plotting/121603 "2024-10-23T13:34:10Z")

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Hi, I am new to SciML and Julia. I am trying to use neural ODE to model the system. Everything else in my code except the plotting works. The problem occurs when I try to plot the prediction vs the original using scatte…

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