# Latest

**URL:** https://discourse.julialang.org/latest.md?page=756

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

**Page:** 757

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## [Performance of a transpose compared to c and cache friendliness](https://discourse.julialang.org/t/performance-of-a-transpose-compared-to-c-and-cache-friendliness/95883)

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**Author:** [@sneakyturtle](https://discourse.julialang.org/u/sneakyturtle)\
**Replies:** 6\
**Last updated:** [March 11, 2023, 3:33pm UTC](https://discourse.julialang.org/t/performance-of-a-transpose-compared-to-c-and-cache-friendliness/95883 "2023-03-11T15:33:01Z")

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In a quest to learn good HPC principles, I am trying to understand how to implement cache friendly loops in Julia. I found this code loop\_blocking that compares performance of loop blocking techniques between c and Rust…

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## [How do I avoid atomics in this kind of code on GPU?](https://discourse.julialang.org/t/how-do-i-avoid-atomics-in-this-kind-of-code-on-gpu/95881)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 2\
**Last updated:** [March 11, 2023, 8:39am UTC](https://discourse.julialang.org/t/how-do-i-avoid-atomics-in-this-kind-of-code-on-gpu/95881 "2023-03-11T08:39:14Z")

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I want to stress that this is a toy example. It is not a real calculation. It is a toy example, intended to be a minimal working example. It is showing some approach I want to apply to a problem of mine Hello! I am wri…

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## [Docstring: how to format returns](https://discourse.julialang.org/t/docstring-how-to-format-returns/95850)

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**Author:** [@AdamWysokinski](https://discourse.julialang.org/u/AdamWysokinski)\
**Replies:** 3\
**Last updated:** [March 11, 2023, 8:36am UTC](https://discourse.julialang.org/t/docstring-how-to-format-returns/95850 "2023-03-11T08:36:50Z")

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Hi, I wonder if there is any standardized way of reporting function return in its docstring for something like this: """ test(x) Test whether \`x\` is greater than 0. # Arguments - \`x::Int64\`: the number to test …

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## [Type Nothing has no field match](https://discourse.julialang.org/t/type-nothing-has-no-field-match/95904)

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**Author:** [@hungpham3112](https://discourse.julialang.org/u/hungpham3112)\
**Replies:** 1\
**Last updated:** [March 11, 2023, 5:57am UTC](https://discourse.julialang.org/t/type-nothing-has-no-field-match/95904 "2023-03-11T05:57:27Z")

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I’m learning Linear Regression model with housing dataset from Kaggle. Dealing with a problem to extract int or float from string make me some confusing. # rename columns renamed\_df = rename(df2, Dict("Diện tích" =\> "A…

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## [Two Julia meetings in Bombay, 22 March](https://discourse.julialang.org/t/two-julia-meetings-in-bombay-22-march/95903)

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**Author:** [@Ajay\_Shah](https://discourse.julialang.org/u/Ajay_Shah)\
**Replies:** 0\
**Last updated:** [March 11, 2023, 4:52am UTC](https://discourse.julialang.org/t/two-julia-meetings-in-bombay-22-march/95903 "2023-03-11T04:52:23Z")

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On 22 March, we have Sharan Yalburgi teaching Probabilistic programming in Julia \[meetup.com\]. And on the same day, we have the second Bombay Julia Meetup \[meetup.com\].

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## [Raw HTML in docstring](https://discourse.julialang.org/t/raw-html-in-docstring/95491)

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**Author:** [@pedromxavier](https://discourse.julialang.org/u/pedromxavier)\
**Replies:** 3\
**Last updated:** [March 11, 2023, 3:33am UTC](https://discourse.julialang.org/t/raw-html-in-docstring/95491 "2023-03-11T03:33:03Z")

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I’m using Documenter.jl to generate online docs for my package. I want to include raw HTML in a method docstring such as: @doc raw""" my\_method(x, y) This is my method. Now some raw HTML: \`\`\`@raw html \<svg style="…

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## [FFTW plan gets clobbered when module is compiled](https://discourse.julialang.org/t/fftw-plan-gets-clobbered-when-module-is-compiled/95896)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 1\
**Last updated:** [March 11, 2023, 1:53am UTC](https://discourse.julialang.org/t/fftw-plan-gets-clobbered-when-module-is-compiled/95896 "2023-03-11T01:53:22Z")

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I have a function that calls fft() repeatedly. For performance I implemented an FFT plan. In some situations the length of data will remain the same, in other cases the the length changes. For this reason the plan is …

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## [Interpolations of a function that has NaN](https://discourse.julialang.org/t/interpolations-of-a-function-that-has-nan/95704)

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**Author:** [@roi.holtzman](https://discourse.julialang.org/u/roi.holtzman)\
**Replies:** 9\
**Last updated:** [March 11, 2023, 1:29am UTC](https://discourse.julialang.org/t/interpolations-of-a-function-that-has-nan/95704 "2023-03-11T01:29:11Z")

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I am trying to interpolate a 2d function that is defined only on a partial set of my parameters. Where it is not defined, my 2d array has NaNs. Note that in my example the range of where the function is defined is not a…

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## [Best way to avoid singular matrix crashing optimization routine](https://discourse.julialang.org/t/best-way-to-avoid-singular-matrix-crashing-optimization-routine/95897)

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**Author:** [@jrhalket](https://discourse.julialang.org/u/jrhalket)\
**Replies:** 1\
**Last updated:** [March 11, 2023, 12:18am UTC](https://discourse.julialang.org/t/best-way-to-avoid-singular-matrix-crashing-optimization-routine/95897 "2023-03-11T00:18:57Z")

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I have a log likelihood function I’m trying to maximize and as part of the computation of the log likelihood I call a function ScalcAll which performs the following calcs, including inverting a matrix. up and down are da…

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## [Lorentz Vector reusability for QED.jl (event generator)](https://discourse.julialang.org/t/lorentz-vector-reusability-for-qed-jl-event-generator/95871)

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**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 2\
**Last updated:** [March 10, 2023, 11:54pm UTC](https://discourse.julialang.org/t/lorentz-vector-reusability-for-qed-jl-event-generator/95871 "2023-03-10T23:54:13Z")

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I was watching in awe of https://www.youtube.com/watch?v=BqRps2dwLxE by @szabo137. Afterwards @peremato asked one of the questions I had which is why not re-use some of the existing JuliaHEP stuff, simplest example being…

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## [Vector of Rational{Int64}](https://discourse.julialang.org/t/vector-of-rational-int64/95891)

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**Author:** [@Cougar](https://discourse.julialang.org/u/Cougar)\
**Replies:** 1\
**Last updated:** [March 10, 2023, 10:14pm UTC](https://discourse.julialang.org/t/vector-of-rational-int64/95891 "2023-03-10T22:14:56Z")

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Does anyone know why the following … rationalVector::Vector{Rational{Int64}} = \[ (2//3), (5//8), (11//17), (44/101) \] for rational in rationalVector println(rational) end # for rational … prints the following … 600…

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## [(help request) using ArchGDAL.gdalwarp() for resampling a raster dataset](https://discourse.julialang.org/t/help-request-using-archgdal-gdalwarp-for-resampling-a-raster-dataset/47039)

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**Author:** [@vlandau](https://discourse.julialang.org/u/vlandau)\
**Replies:** 9\
**Last updated:** [March 10, 2023, 9:00pm UTC](https://discourse.julialang.org/t/help-request-using-archgdal-gdalwarp-for-resampling-a-raster-dataset/47039 "2023-03-10T21:00:08Z")

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Hi all, I’m struggling to figure out how to use ArchGDAL.gdalwarp (currently only unsafe\_gdalwarp is documented). ArchGDAL.gdalwarp’s first parameter being a function is a bit confusing as well. Here’s the GDAL CLI vers…

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## [Sieving for Bsmooth values](https://discourse.julialang.org/t/sieving-for-bsmooth-values/95404)

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**Author:** [@x13420x](https://discourse.julialang.org/u/x13420x)\
**Replies:** 15\
**Last updated:** [March 9, 2023, 9:26pm UTC](https://discourse.julialang.org/t/sieving-for-bsmooth-values/95404 "2023-03-09T21:26:25Z")

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I am playing around with a quadratic sieve for factorization of large numbers. Most of the work of this algorithm is searching for Bsmooth numbers. If you know the sieve of eratosthenes you can use this process to siev…

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## [Constriant in ADNLPModels package](https://discourse.julialang.org/t/constriant-in-adnlpmodels-package/95832)

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**Author:** [@X\_Chen](https://discourse.julialang.org/u/X_Chen)\
**Replies:** 4\
**Last updated:** [March 10, 2023, 8:29pm UTC](https://discourse.julialang.org/t/constriant-in-adnlpmodels-package/95832 "2023-03-10T20:29:09Z")

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Hi everyone, I am trying to do a nonlinear optimization with six parameters using the ADNLModles package. For example: function constriants(para) cons=1-para\[1\]^2-para\[2\]^2-para\[3\]^2+2\*para\[1\]\*para\[2\]\*para\[3\] r…

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## [How to read only the last line of a file (.txt)?](https://discourse.julialang.org/t/how-to-read-only-the-last-line-of-a-file-txt/68005)

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**Author:** [@guilhermebodin](https://discourse.julialang.org/u/guilhermebodin)\
**Replies:** 24\
**Last updated:** [September 12, 2021, 6:48pm UTC](https://discourse.julialang.org/t/how-to-read-only-the-last-line-of-a-file-txt/68005 "2021-09-12T18:48:45Z")

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Hello, I have a very large txt file and would like to read only the last line of it. What is the best way to do it? For example if I have this file some header option header other option random metadata A,B,C,X,Y,Z 1,…

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## [Serverless framework](https://discourse.julialang.org/t/serverless-framework/10255)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 7\
**Last updated:** [March 10, 2023, 7:29pm UTC](https://discourse.julialang.org/t/serverless-framework/10255 "2023-03-10T19:29:18Z")

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Anyone thought about making Julia available on serverless framework? https://github.com/serverless/serverless

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## [Step-by-step tutorial about deep learning using Julia for beginners](https://discourse.julialang.org/t/step-by-step-tutorial-about-deep-learning-using-julia-for-beginners/95876)

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**Author:** [@germanov\_dev](https://discourse.julialang.org/u/germanov_dev)\
**Replies:** 0\
**Last updated:** [March 10, 2023, 5:06pm UTC](https://discourse.julialang.org/t/step-by-step-tutorial-about-deep-learning-using-julia-for-beginners/95876 "2023-03-10T17:06:53Z")

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## [Code compiles each time it triggered](https://discourse.julialang.org/t/code-compiles-each-time-it-triggered/95839)

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**Author:** [@Sandy45](https://discourse.julialang.org/u/Sandy45)\
**Replies:** 6\
**Last updated:** [March 10, 2023, 6:08pm UTC](https://discourse.julialang.org/t/code-compiles-each-time-it-triggered/95839 "2023-03-10T18:08:37Z")

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I’ve deployed my Julia code to AWS using Docker containers with enabling multiple threads, The issue we are facing is whenever HTTP end point (Julia) has been triggered process is compiling every time since because of us…

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## [Error deploying documentation after moving repo to organization](https://discourse.julialang.org/t/error-deploying-documentation-after-moving-repo-to-organization/95877)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 2\
**Last updated:** [March 10, 2023, 5:50pm UTC](https://discourse.julialang.org/t/error-deploying-documentation-after-moving-repo-to-organization/95877 "2023-03-10T17:50:00Z")

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Hi there, I’ve recently moved some of my repos into a new GitHub organisation. After merging a pull request today, I realised that the documentation is no longer deployed: ┌ Info: Deployment criteria for deploying devb…

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## [JuMP/CPLEX: seemingly not all lazy cuts are respected](https://discourse.julialang.org/t/jump-cplex-seemingly-not-all-lazy-cuts-are-respected/95798)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 4\
**Last updated:** [March 10, 2023, 5:44pm UTC](https://discourse.julialang.org/t/jump-cplex-seemingly-not-all-lazy-cuts-are-respected/95798 "2023-03-10T17:44:41Z")

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Dear folks, it seems that CPLEX sometimes does not respect all lazy cuts in the final solution. I know that there is no guarantee that it respects submitted cuts immediately, but it should do in the final solution afaik…

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## [Data racing with @threads with "for-loop"](https://discourse.julialang.org/t/data-racing-with-threads-with-for-loop/95863)

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**Author:** [@Zerosum](https://discourse.julialang.org/u/Zerosum)\
**Replies:** 3\
**Last updated:** [March 10, 2023, 5:19pm UTC](https://discourse.julialang.org/t/data-racing-with-threads-with-for-loop/95863 "2023-03-10T17:19:54Z")

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I figured out that my code is having a data-race problem with @threads. However, I cannot see what is causing the problem and how I can fix this. ### Generate deterministic sequence trial = seq\_generator(sobol\_n); ##…

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## [Equivalent of \`last\` for iterators](https://discourse.julialang.org/t/equivalent-of-last-for-iterators/95874)

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**Author:** [@Dan](https://discourse.julialang.org/u/Dan)\
**Replies:** 1\
**Last updated:** [March 10, 2023, 5:13pm UTC](https://discourse.julialang.org/t/equivalent-of-last-for-iterators/95874 "2023-03-10T17:13:05Z")

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While responding to a different topic, I needed the last element of an iterator. This has at least one fairly simple and efficient solution which has appeared elsewhere: itrlast(itr) = foldl((\_,y)-\>y,itr) but last can …

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## [\`TagBot\`: release for new version not automatically triggered](https://discourse.julialang.org/t/tagbot-release-for-new-version-not-automatically-triggered/95179)

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**Author:** [@pat-alt](https://discourse.julialang.org/u/pat-alt)\
**Replies:** 7\
**Last updated:** [March 10, 2023, 5:15pm UTC](https://discourse.julialang.org/t/tagbot-release-for-new-version-not-automatically-triggered/95179 "2023-03-10T17:15:46Z")

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Hi there, I recently moved various packages from my own GitHub account into a new organisation. Yesterday, I added a new release for one of them to General and as usual TagBot was triggered (see here). I can also see th…

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## [How can I assing an Unitful.jl quantity in an idempotent way?](https://discourse.julialang.org/t/how-can-i-assing-an-unitful-jl-quantity-in-an-idempotent-way/95864)

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**Author:** [@bertulli](https://discourse.julialang.org/u/bertulli)\
**Replies:** 4\
**Last updated:** [March 10, 2023, 5:11pm UTC](https://discourse.julialang.org/t/how-can-i-assing-an-unitful-jl-quantity-in-an-idempotent-way/95864 "2023-03-10T17:11:04Z")

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Hi all! So I need to manipulate some physical quantities. Unitful.jl seems to do a very good job at it, but IIUC the idiomatic way to “build” a physical quantity is to multiply the number and the unit: 12 \* u"m". The …

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## [Cannot show that the matrix form of my SPD preconditioner is SPD](https://discourse.julialang.org/t/cannot-show-that-the-matrix-form-of-my-spd-preconditioner-is-spd/95869)

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**Author:** [@nvenkov1](https://discourse.julialang.org/u/nvenkov1)\
**Replies:** 4\
**Last updated:** [March 10, 2023, 4:12pm UTC](https://discourse.julialang.org/t/cannot-show-that-the-matrix-form-of-my-spd-preconditioner-is-spd/95869 "2023-03-10T16:12:50Z")

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I define a symmetric positive definite (SPD) matrix A. Then, based on this matrix, I define two preconditioners, which should also be SPD, namely an AMG and a Cholesky factorization. Both preconditioners are matrix-free.…

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## [Using Enzyme with DE.jl](https://discourse.julialang.org/t/using-enzyme-with-de-jl/95302)

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**Author:** [@tomkimpson](https://discourse.julialang.org/u/tomkimpson)\
**Replies:** 3\
**Last updated:** [March 10, 2023, 1:30pm UTC](https://discourse.julialang.org/t/using-enzyme-with-de-jl/95302 "2023-03-10T13:30:11Z")

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I am playing with using Enzyme.jl to try to get the derivative of some numerical function with respect to the initial condition. The function is solved using DifferentialEquations.jl. For example: using DifferentialEqua…

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## [ControlSystemIdentification](https://discourse.julialang.org/t/controlsystemidentification/95794)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 12\
**Last updated:** [March 10, 2023, 1:18pm UTC](https://discourse.julialang.org/t/controlsystemidentification/95794 "2023-03-10T13:18:07Z")

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Hello, I am trying out the package ControlSystemIdentification. It looks very good, each step very well explained! One question: In the example Temperature control · ControlSystemIdentification Documentation you are u…

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## [How to solve two-dimensional transient partial differential equations?](https://discourse.julialang.org/t/how-to-solve-two-dimensional-transient-partial-differential-equations/92317)

<div class="topic-metadata">

**Author:** [@abhayguleria92](https://discourse.julialang.org/u/abhayguleria92)\
**Replies:** 4\
**Last updated:** [March 10, 2023, 12:58pm UTC](https://discourse.julialang.org/t/how-to-solve-two-dimensional-transient-partial-differential-equations/92317 "2023-03-10T12:58:44Z")

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Dear Julia community, I am beginner to Julia. Kindly suggest me a suitable resource (packages) to solve coupled PDEs via Finite-difference method or any other numerical method? Please see the equations in shared image …

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## [Improving for loop speed in recursive calculation](https://discourse.julialang.org/t/improving-for-loop-speed-in-recursive-calculation/95848)

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**Author:** [@marianoarnaiz](https://discourse.julialang.org/u/marianoarnaiz)\
**Replies:** 1\
**Last updated:** [March 10, 2023, 12:15pm UTC](https://discourse.julialang.org/t/improving-for-loop-speed-in-recursive-calculation/95848 "2023-03-10T12:15:04Z")

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Hi all. I am building a little function that does some recursive computation. it will be working in very large datasets and I want to speed it up. Maybe someone can give a helping hand? :slight\_smile: function rec\_ho…

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## [Raise or throw in documentation](https://discourse.julialang.org/t/raise-or-throw-in-documentation/95854)

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**Author:** [@Euhan](https://discourse.julialang.org/u/Euhan)\
**Replies:** 1\
**Last updated:** [March 10, 2023, 12:09pm UTC](https://discourse.julialang.org/t/raise-or-throw-in-documentation/95854 "2023-03-10T12:09:23Z")

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What is the difference between raising an exception and throwing one? I am labouring under the apprehension that these two really are the same. If this is not so, it would be interesting to know the distinction, otherwi…

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