# Latest

**URL:** https://discourse.julialang.org/latest.md?page=962

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

**Page:** 963

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## [Question on how to define equation system in DiffEq using Matrix form](https://discourse.julialang.org/t/question-on-how-to-define-equation-system-in-diffeq-using-matrix-form/85286)

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**Author:** [@kwwong333](https://discourse.julialang.org/u/kwwong333)\
**Replies:** 1\
**Last updated:** [August 4, 2022, 10:42am UTC](https://discourse.julialang.org/t/question-on-how-to-define-equation-system-in-diffeq-using-matrix-form/85286 "2022-08-04T10:42:39Z")

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Hello Guys, Previously, we handled CFD problems involving algebraic equations in the form of a matrix using a simple self-coded and stupid solver :). After reading the capability of Diffeq, we would like to move into Di…

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## [Doing CCA/CVA in Julia with MultivariateStats.jl package - how to get canonical vectors?](https://discourse.julialang.org/t/doing-cca-cva-in-julia-with-multivariatestats-jl-package-how-to-get-canonical-vectors/43626)

<div class="topic-metadata">

**Author:** [@cheins](https://discourse.julialang.org/u/cheins)\
**Replies:** 1\
**Last updated:** [August 4, 2022, 10:09am UTC](https://discourse.julialang.org/t/doing-cca-cva-in-julia-with-multivariatestats-jl-package-how-to-get-canonical-vectors/43626 "2022-08-04T10:09:32Z")

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I am using the fit(CCA,...) function from the MultivariateStats.jl package and I want to know how to pull out the principal canonical vectors. The resulting CCA model object has methods like xprojection and ypro…

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## [MOSEK fatal error stopenv](https://discourse.julialang.org/t/mosek-fatal-error-stopenv/51590)

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**Author:** [@cyanzhao42](https://discourse.julialang.org/u/cyanzhao42)\
**Replies:** 5\
**Last updated:** [August 4, 2022, 9:24am UTC](https://discourse.julialang.org/t/mosek-fatal-error-stopenv/51590 "2022-08-04T09:24:13Z")

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Hi all, I try to use JuMP with MOSEK. After formulated the problem, and start solving the problem, I have received this error message. Any suggestions on what going on here or how I can figure this out? Thanks! MOSEK f…

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## [How to debug a script in existing REPL using VSCode](https://discourse.julialang.org/t/how-to-debug-a-script-in-existing-repl-using-vscode/60822)

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**Author:** [@RGerzaguet](https://discourse.julialang.org/u/RGerzaguet)\
**Replies:** 3\
**Last updated:** [August 4, 2022, 9:17am UTC](https://discourse.julialang.org/t/how-to-debug-a-script-in-existing-repl-using-vscode/60822 "2022-08-04T09:17:42Z")

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Hello all, I often use VSCode when I want to debug code and I conversely put breakpoints into functions and call the functions in my Julia session (in the REPL) using the macro @run myFunc(x) (or even @enter). This work…

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## [IJulia and Pyplot backend problem with old Python version](https://discourse.julialang.org/t/ijulia-and-pyplot-backend-problem-with-old-python-version/85216)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 12\
**Last updated:** [August 4, 2022, 8:46am UTC](https://discourse.julialang.org/t/ijulia-and-pyplot-backend-problem-with-old-python-version/85216 "2022-08-04T08:46:33Z")

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Hi all, I have upgraded my Python to 3.10 just to be able to use Pyplot backend (do not know if it is worth the trouble, perhaps other backend is better) I want to plot this: using Plots; pyplot(); xc = \[0,0,1,1\] yc …

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## [Julia 1.7.3 Build Fails on M1 MAC Pro](https://discourse.julialang.org/t/julia-1-7-3-build-fails-on-m1-mac-pro/85270)

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**Author:** [@Nitin\_Arora](https://discourse.julialang.org/u/Nitin_Arora)\
**Replies:** 3\
**Last updated:** [August 4, 2022, 7:20am UTC](https://discourse.julialang.org/t/julia-1-7-3-build-fails-on-m1-mac-pro/85270 "2022-08-04T07:20:30Z")

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I am trying to compile Julia (V 1.7.3) on M1 Mac Pro but it seems to be failing with Error 138 : CC src/llvm-remove-ni.o CC src/llvm-julia-licm.o CC src/llvm-demote-float16.o LINK usr/lib/libjulia-internal…

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## [Rename columns in view](https://discourse.julialang.org/t/rename-columns-in-view/85272)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 4\
**Last updated:** [August 4, 2022, 6:37am UTC](https://discourse.julialang.org/t/rename-columns-in-view/85272 "2022-08-04T06:37:04Z")

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Is it possible to rename columns in a DataFrame view ? (without altering the column names in the underlying DataFrame)

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## [Parallel computing of matrix with @threads](https://discourse.julialang.org/t/parallel-computing-of-matrix-with-threads/85228)

<div class="topic-metadata">

**Author:** [@lukemin](https://discourse.julialang.org/u/lukemin)\
**Replies:** 3\
**Last updated:** [August 4, 2022, 5:03am UTC](https://discourse.julialang.org/t/parallel-computing-of-matrix-with-threads/85228 "2022-08-04T05:03:47Z")

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Hi, I am trying to implement some multi-threading on my project written in julia. Although, it seems that @threads macro does not work as I intended. I have tried almost every solutions / multithreading methods I could f…

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## [How to read .json file in dataframe without using Pandas.jl](https://discourse.julialang.org/t/how-to-read-json-file-in-dataframe-without-using-pandas-jl/85276)

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**Author:** [@Starpower\_Power](https://discourse.julialang.org/u/Starpower_Power)\
**Replies:** 1\
**Last updated:** [August 4, 2022, 3:36am UTC](https://discourse.julialang.org/t/how-to-read-json-file-in-dataframe-without-using-pandas-jl/85276 "2022-08-04T03:36:38Z")

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how to read .json file in dataframe without using Pandas.jl, because using both package there will conflict error.

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## [Symbolics.jl | Interfacing - building an expression tree to use custom rules](https://discourse.julialang.org/t/symbolics-jl-interfacing-building-an-expression-tree-to-use-custom-rules/85264)

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**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 4\
**Last updated:** [August 4, 2022, 12:44am UTC](https://discourse.julialang.org/t/symbolics-jl-interfacing-building-an-expression-tree-to-use-custom-rules/85264 "2022-08-04T00:44:09Z")

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Hello, I would like to use the SymbolicUtils composing rewriter Fixpoint(rw) which returns a rewriter which applies rw repeatedly until there are no changes to be made to apply a custom rule to a Symbolics.jl expres…

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## [Pushing to an array which is an element of another array (Modifying an array in an array)](https://discourse.julialang.org/t/pushing-to-an-array-which-is-an-element-of-another-array-modifying-an-array-in-an-array/85179)

<div class="topic-metadata">

**Author:** [@Jonas208](https://discourse.julialang.org/u/Jonas208)\
**Replies:** 11\
**Last updated:** [August 3, 2022, 10:45pm UTC](https://discourse.julialang.org/t/pushing-to-an-array-which-is-an-element-of-another-array-modifying-an-array-in-an-array/85179 "2022-08-03T22:45:41Z")

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Imagine the following situation: I create an array with a fixed size and every element in this array is another array. In a loop, I want to push tuples to one array of the outer array. So I want to modify one array wh…

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## [Change width of a particular stack in Makie bar plot](https://discourse.julialang.org/t/change-width-of-a-particular-stack-in-makie-bar-plot/85269)

<div class="topic-metadata">

**Author:** [@math\_opt](https://discourse.julialang.org/u/math_opt)\
**Replies:** 0\
**Last updated:** [August 3, 2022, 10:30pm UTC](https://discourse.julialang.org/t/change-width-of-a-particular-stack-in-makie-bar-plot/85269 "2022-08-03T22:30:20Z")

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I need to have some customization in my bar plots, and was wondering if someone could help me achieve the following two things: How to specify different widths to different stacks in the bar plot? For example, in the p…

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## [How to initialize an array of Turing variables?](https://discourse.julialang.org/t/how-to-initialize-an-array-of-turing-variables/85205)

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**Author:** [@jpm](https://discourse.julialang.org/u/jpm)\
**Replies:** 2\
**Last updated:** [August 3, 2022, 9:46pm UTC](https://discourse.julialang.org/t/how-to-initialize-an-array-of-turing-variables/85205 "2022-08-03T21:46:31Z")

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I am new to Turing and in the process of translating a complex dynamical stochastic model from Stan to Turing. Instead of declaring individual variables (many of them arrays), I would like to include them in a dictionary…

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## [\[pre-ANN/RFC\] VectorInterface.jl](https://discourse.julialang.org/t/pre-ann-rfc-vectorinterface-jl/85231)

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**Author:** [@juthohaegeman](https://discourse.julialang.org/u/juthohaegeman)\
**Replies:** 4\
**Last updated:** [August 3, 2022, 8:34pm UTC](https://discourse.julialang.org/t/pre-ann-rfc-vectorinterface-jl/85231 "2022-08-03T20:34:22Z")

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This is more a “request for comments” than an announcement. I’ve just created (but not registered) a package called VectorInterface.jl. Why? The following is a copy of the README. It is long, but I wanted to do a decent …

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## [Q: using Latexify.jl in VS Code](https://discourse.julialang.org/t/q-using-latexify-jl-in-vs-code/85136)

<div class="topic-metadata">

**Author:** [@Audrius-St](https://discourse.julialang.org/u/Audrius-St)\
**Replies:** 7\
**Last updated:** [August 3, 2022, 9:07pm UTC](https://discourse.julialang.org/t/q-using-latexify-jl-in-vs-code/85136 "2022-08-03T21:07:13Z")

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Hello, I would like to display an equation using Latexify in the VS Code IDE. The MWE is # test\_latexify\_main.jl using Symbolics using Latexify function main() @variables x, t @variables Φ(x, t) Dx = …

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## [Negative zeros and sorting](https://discourse.julialang.org/t/negative-zeros-and-sorting/85252)

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**Author:** [@Gus\_Hart](https://discourse.julialang.org/u/Gus_Hart)\
**Replies:** 13\
**Last updated:** [August 3, 2022, 8:04pm UTC](https://discourse.julialang.org/t/negative-zeros-and-sorting/85252 "2022-08-03T20:04:43Z")

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Negative zeros are equivalent to positive zeros, and yet in sorting the negatives come before positives. This behavior caused a very subtle bug in a function I wrote to compare clusters of points. I’m wondering if there …

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## [Canceled JuliaCon talks](https://discourse.julialang.org/t/canceled-juliacon-talks/84997)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 6\
**Last updated:** [August 3, 2022, 7:39pm UTC](https://discourse.julialang.org/t/canceled-juliacon-talks/84997 "2022-08-03T19:39:42Z")

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Is there a location where I can see all JuliaCon talks, included canceled ones? I could swear there was a talk called “Graph Algorithms in SuiteSparseGraphBLAS.jl” but I can not seem to find it anymore in the schedule.

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## [Optim.jl - get the hessian matrix from maximum likelihood estimation](https://discourse.julialang.org/t/optim-jl-get-the-hessian-matrix-from-maximum-likelihood-estimation/70615)

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**Author:** [@Strange\_Xue](https://discourse.julialang.org/u/Strange_Xue)\
**Replies:** 6\
**Last updated:** [August 3, 2022, 7:13pm UTC](https://discourse.julialang.org/t/optim-jl-get-the-hessian-matrix-from-maximum-likelihood-estimation/70615 "2022-08-03T19:13:11Z")

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There exists an example at Optim.jl’s tutorial, I copy the code here. using Optim, NLSolversBase, Random using LinearAlgebra: diag Random.seed!(0); # Fix random seed generator for reproducibil…

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## [How to use custom back end model with Genie MVC app?](https://discourse.julialang.org/t/how-to-use-custom-back-end-model-with-genie-mvc-app/85257)

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**Author:** [@Jack\_N](https://discourse.julialang.org/u/Jack_N)\
**Replies:** 0\
**Last updated:** [August 3, 2022, 6:45pm UTC](https://discourse.julialang.org/t/how-to-use-custom-back-end-model-with-genie-mvc-app/85257 "2022-08-03T18:45:47Z")

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I am trying to use Genie to create a MVC structured web application, but I have not figured out how to include something other than a database retrieval system for the model. I have read the entire documentation and the…

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## [Image Partition into Blocks](https://discourse.julialang.org/t/image-partition-into-blocks/85238)

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**Author:** [@lgmendes](https://discourse.julialang.org/u/lgmendes)\
**Replies:** 3\
**Last updated:** [August 3, 2022, 6:36pm UTC](https://discourse.julialang.org/t/image-partition-into-blocks/85238 "2022-08-03T18:36:48Z")

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What is the equivalent Julia function of the Wolfram Mathematica ImagePartition function ( ImagePartition—Wolfram Language Documentation )

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## [Simple type/array problem](https://discourse.julialang.org/t/simple-type-array-problem/85251)

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**Author:** [@ArminAminian](https://discourse.julialang.org/u/ArminAminian)\
**Replies:** 4\
**Last updated:** [August 3, 2022, 6:26pm UTC](https://discourse.julialang.org/t/simple-type-array-problem/85251 "2022-08-03T18:26:22Z")

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d = \[1.3, 2., 3., 4.3\] dd =\[1., 3.\] dd\[2\] = sum(q\[t,1:5\], dims=1); This gives the following errow: MethodError: Cannot convert an object of type Vector{Float64} to an object of type Float64 Closest candidates are: …

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## [Allocations using dualcache](https://discourse.julialang.org/t/allocations-using-dualcache/85244)

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**Author:** [@dbs](https://discourse.julialang.org/u/dbs)\
**Replies:** 1\
**Last updated:** [August 3, 2022, 6:07pm UTC](https://discourse.julialang.org/t/allocations-using-dualcache/85244 "2022-08-03T18:07:22Z")

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I have a rather complicated function that I’ve written in a non-allocating manner, and am now trying to use ForwardDiff.jacobian! to generate a non-allocating jacobian. The function has many substeps, so use of a pre-a…

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## [Optimal Power of N for FFTW](https://discourse.julialang.org/t/optimal-power-of-n-for-fftw/85232)

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**Author:** [@Jake](https://discourse.julialang.org/u/Jake)\
**Replies:** 10\
**Last updated:** [August 3, 2022, 6:05pm UTC](https://discourse.julialang.org/t/optimal-power-of-n-for-fftw/85232 "2022-08-03T18:05:18Z")

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FFTW is fastest when it has small prime factors according to its manual. If there is the option to pad the input data, then with radix 2 FFT algorithms this is done with a “next power of 2” type function. However if th…

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## [Problem with SymPy. Symbolic calculation of Sturm chains (Sturm sequence) for polynomials](https://discourse.julialang.org/t/problem-with-sympy-symbolic-calculation-of-sturm-chains-sturm-sequence-for-polynomials/84921)

<div class="topic-metadata">

**Author:** [@mendeli](https://discourse.julialang.org/u/mendeli)\
**Replies:** 2\
**Last updated:** [August 3, 2022, 4:44pm UTC](https://discourse.julialang.org/t/problem-with-sympy-symbolic-calculation-of-sturm-chains-sturm-sequence-for-polynomials/84921 "2022-08-03T16:44:54Z")

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I was using sympy.sturm() to calculate the Sturm functions of a polynomial and came across an error for a 4th degree polynomial using SymPy begin @vars x # Polynomial coefficients c4 = Sym\[1; -4; 8; -8; 4\] # Probl…

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## [Need help to fix a Pluto downgrade when adding another package](https://discourse.julialang.org/t/need-help-to-fix-a-pluto-downgrade-when-adding-another-package/82698)

<div class="topic-metadata">

**Author:** [@ederag](https://discourse.julialang.org/u/ederag)\
**Replies:** 2\
**Last updated:** [August 3, 2022, 4:30pm UTC](https://discourse.julialang.org/t/need-help-to-fix-a-pluto-downgrade-when-adding-another-package/82698 "2022-08-03T16:30:26Z")

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Adding a package is downgrading Pluto, an MWE showing the error is shown below. Can it be solved ? Or how to find out where to file an issue ? Interpreting and resolving version conflicts is usually enough, but I’d nee…

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## [Command from a string](https://discourse.julialang.org/t/command-from-a-string/85237)

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**Author:** [@whatsthecraic](https://discourse.julialang.org/u/whatsthecraic)\
**Replies:** 1\
**Last updated:** [August 3, 2022, 4:15pm UTC](https://discourse.julialang.org/t/command-from-a-string/85237 "2022-08-03T16:15:36Z")

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Hi there, how can I create & run a command from a string, e.g. julia\> str = "echo hello world" "echo hello world" julia\> read(\`$(str)\`) ERROR: IOError: could not spawn \`'echo hello world'\`: no such file or directory (E…

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## [MQTT message topic parsing optimization](https://discourse.julialang.org/t/mqtt-message-topic-parsing-optimization/85151)

<div class="topic-metadata">

**Author:** [@shindler25](https://discourse.julialang.org/u/shindler25)\
**Replies:** 2\
**Last updated:** [August 3, 2022, 1:23pm UTC](https://discourse.julialang.org/t/mqtt-message-topic-parsing-optimization/85151 "2022-08-03T13:23:58Z")

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Hello, The problem: I am designing an MQTT client using GitHub - rweilbacher/MQTT.jl: An asynchronous MQTT client library for julia and am trying to determine the best way to handle incoming messages. messages are handl…

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## [Strange issues with stride loops as in CUDA.Random](https://discourse.julialang.org/t/strange-issues-with-stride-loops-as-in-cuda-random/85163)

<div class="topic-metadata">

**Author:** [@physicsjoke](https://discourse.julialang.org/u/physicsjoke)\
**Replies:** 1\
**Last updated:** [August 3, 2022, 12:51pm UTC](https://discourse.julialang.org/t/strange-issues-with-stride-loops-as-in-cuda-random/85163 "2022-08-03T12:51:10Z")

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Hello everyone, I’ve been spending quite some time debugging my method to sample gamma-distributed random numbers on my GPU. The algo is quite simple, as my shape parameter (k) is drawn from a Poisson distribution and …

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## [Multiple dispatch of \`in\`](https://discourse.julialang.org/t/multiple-dispatch-of-in/85227)

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**Author:** [@this\_josh](https://discourse.julialang.org/u/this_josh)\
**Replies:** 2\
**Last updated:** [August 3, 2022, 12:48pm UTC](https://discourse.julialang.org/t/multiple-dispatch-of-in/85227 "2022-08-03T12:48:01Z")

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I’d like to customise how in works for a struct I’ve created as only some fields matter. I’d like it to work like this where here I just want to check the dogs breeds: struct Dog breed name end a = Dog("husky",…

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## [Poor scaling results with \`ImplicitGlobalGrid.jl\`](https://discourse.julialang.org/t/poor-scaling-results-with-implicitglobalgrid-jl/65170)

<div class="topic-metadata">

**Author:** [@francispoulin](https://discourse.julialang.org/u/francispoulin)\
**Replies:** 28\
**Last updated:** [August 3, 2022, 12:34pm UTC](https://discourse.julialang.org/t/poor-scaling-results-with-implicitglobalgrid-jl/65170 "2022-08-03T12:34:49Z")

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I have tried running one of the examples of ImplicitGlobalGrid.jl on 1, 2 and 4 gpus to reproduce some scaling results. I started wtih diffusion3D\_multigpu\_CuArray\_novis.jl with a coarser grid to see how it does. Below y…

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