# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1298

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

**Page:** 1299

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## [Broadcasting nothing to DataFrame entries raises MethodError](https://discourse.julialang.org/t/broadcasting-nothing-to-dataframe-entries-raises-methoderror/66436)

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**Author:** [@DaveTJones](https://discourse.julialang.org/u/DaveTJones)\
**Replies:** 5\
**Last updated:** [August 15, 2021, 11:11pm UTC](https://discourse.julialang.org/t/broadcasting-nothing-to-dataframe-entries-raises-methoderror/66436 "2021-08-15T23:11:24Z")

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Hi, I’m learning my way around DataFrames.jl and CSV.jl and am having some difficulty understanding the behaviour of the following code; using DataFrames, CSV x = rand(5, 5) A = DataFrame(x, :auto) A\[2:4, 2:4\] .= m…

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## [How to "unshare" an array?](https://discourse.julialang.org/t/how-to-unshare-an-array/66441)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 7\
**Last updated:** [August 15, 2021, 8:49pm UTC](https://discourse.julialang.org/t/how-to-unshare-an-array/66441 "2021-08-15T20:49:35Z")

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I want to efficiently build up a large matrix in a loop. At every iteration I will: Perform some linear algebra operations on the matrix (it’s more complicated than the example below), and Append a new row to the matr…

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## [Radial basis function](https://discourse.julialang.org/t/radial-basis-function/66446)

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**Author:** [@Manisha\_07](https://discourse.julialang.org/u/Manisha_07)\
**Replies:** 0\
**Last updated:** [August 15, 2021, 10:37pm UTC](https://discourse.julialang.org/t/radial-basis-function/66446 "2021-08-15T22:37:09Z")

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Hello Guys Now i have come up with new doubts I need to use 2nd order differencial equation and used radial basis function for approximating the solution Please let me know how to solve 2nd order differencial equation…

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## [\[ANN\] ONNX export for Flux models](https://discourse.julialang.org/t/ann-onnx-export-for-flux-models/33829)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 12\
**Last updated:** [August 15, 2021, 8:50pm UTC](https://discourse.julialang.org/t/ann-onnx-export-for-flux-models/33829 "2021-08-15T20:50:23Z")

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Hi, After not being able to find a persistent enough serialization format I whipped together a small package which translates models into an ONNX graph: Simple example: using ONNXmutable, Flux l1 = Conv((3,3), 2=\>3…

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## [How to convert a multivariable polynomial with integer coefficients to one with Float64 coefficients?](https://discourse.julialang.org/t/how-to-convert-a-multivariable-polynomial-with-integer-coefficients-to-one-with-float64-coefficients/66438)

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**Author:** [@geo](https://discourse.julialang.org/u/geo)\
**Replies:** 2\
**Last updated:** [August 15, 2021, 5:42pm UTC](https://discourse.julialang.org/t/how-to-convert-a-multivariable-polynomial-with-integer-coefficients-to-one-with-float64-coefficients/66438 "2021-08-15T17:42:57Z")

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The following code works, but seems ugly. There should be a better way to convert than multiplying by 1.0! using DynamicPolynomials @polyvar x\[1:3\] m = monomials(x, 0:3) mD = differentiate.(m, x\[1\]) \*1.0

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## [ModelingToolkit - MethodError on isequal()](https://discourse.julialang.org/t/modelingtoolkit-methoderror-on-isequal/66440)

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**Author:** [@braamvandyk](https://discourse.julialang.org/u/braamvandyk)\
**Replies:** 2\
**Last updated:** [August 15, 2021, 5:33pm UTC](https://discourse.julialang.org/t/modelingtoolkit-methoderror-on-isequal/66440 "2021-08-15T17:33:11Z")

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My apologies if this is something really simple. I have looked at the docs and whatever examples I could find, but I am beginning to confuse the trees for the forest. Any directions would be greatly appreciated. I am tr…

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## [How to print partial differential equation in desired format?](https://discourse.julialang.org/t/how-to-print-partial-differential-equation-in-desired-format/66411)

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**Author:** [@rsavageatx](https://discourse.julialang.org/u/rsavageatx)\
**Replies:** 2\
**Last updated:** [August 15, 2021, 4:56pm UTC](https://discourse.julialang.org/t/how-to-print-partial-differential-equation-in-desired-format/66411 "2021-08-15T16:56:21Z")

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I am using Julia and Sympy to solve a partial differential equation and am having problems printing one of my equations in the format that I desire. This is the code that I am using: function diffeq\_3() @vars z t P, ∇…

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## [Horovod and Flux / Julia](https://discourse.julialang.org/t/horovod-and-flux-julia/53550)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 7\
**Last updated:** [August 15, 2021, 4:46pm UTC](https://discourse.julialang.org/t/horovod-and-flux-julia/53550 "2021-08-15T16:46:14Z")

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Hi all, I wonder if anyone was trying to use horovod with Flux (or Julia in general). Thanks for a answer. Best wishes, Tomas

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## [Rationale for kwargs as Iterators.Pairs](https://discourse.julialang.org/t/rationale-for-kwargs-as-iterators-pairs/66435)

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**Author:** [@sijo](https://discourse.julialang.org/u/sijo)\
**Replies:** 4\
**Last updated:** [August 15, 2021, 3:17pm UTC](https://discourse.julialang.org/t/rationale-for-kwargs-as-iterators-pairs/66435 "2021-08-15T15:17:01Z")

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I’m curious why the keyword arguments are available wrapped in Iterators.Pairs in the function body: function f(; kwargs...) # kwargs is a NamedTuple wrapped in an Iterators.Pairs end Is it legacy cruft from a time…

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## [Faster counting of sequences](https://discourse.julialang.org/t/faster-counting-of-sequences/66359)

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**Author:** [@danielw2904](https://discourse.julialang.org/u/danielw2904)\
**Replies:** 10\
**Last updated:** [August 15, 2021, 3:00pm UTC](https://discourse.julialang.org/t/faster-counting-of-sequences/66359 "2021-08-15T15:00:14Z")

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I have a problem in which I am trying to figure out how many items were first selected by user i and later by user j for all users. My idea was to create a sparse matrix M with n-users \\times n-users in which the rows s…

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## [Idiomatic Pluto flow control](https://discourse.julialang.org/t/idiomatic-pluto-flow-control/66418)

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**Author:** [@dcgrigsby](https://discourse.julialang.org/u/dcgrigsby)\
**Replies:** 1\
**Last updated:** [August 15, 2021, 2:27pm UTC](https://discourse.julialang.org/t/idiomatic-pluto-flow-control/66418 "2021-08-15T14:27:52Z")

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I’d like some advice on how to idiomatically use flow control with Pluto. Here is a minimal example in pseudo code. Let’s say I want to do conditional evaluation. Here’s bare pseudo code of what I’m after that I’d use…

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## [Conda taking forever to install Jupyter lab](https://discourse.julialang.org/t/conda-taking-forever-to-install-jupyter-lab/66156)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 11\
**Last updated:** [August 15, 2021, 2:22pm UTC](https://discourse.julialang.org/t/conda-taking-forever-to-install-jupyter-lab/66156 "2021-08-15T14:22:04Z")

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to get my kids back into the idea of school, I started doing some simple physics experiments with them. We’ve got some data and I wrote a Jupyter notebook to analyze. Then I went to install Jupyter lab on their computers…

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## [Is there any way to explicitly prohibit a function from modifying the \`mutable struct\` or \`Vector/Array\` parameters?](https://discourse.julialang.org/t/is-there-any-way-to-explicitly-prohibit-a-function-from-modifying-the-mutable-struct-or-vector-array-parameters/66416)

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**Author:** [@Pingzi\_Kang](https://discourse.julialang.org/u/Pingzi_Kang)\
**Replies:** 5\
**Last updated:** [August 15, 2021, 1:56pm UTC](https://discourse.julialang.org/t/is-there-any-way-to-explicitly-prohibit-a-function-from-modifying-the-mutable-struct-or-vector-array-parameters/66416 "2021-08-15T13:56:57Z")

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As we know, Julia’s functions can modify the contents of the passed mutable struct or Array. Sometimes this can cause confusion as to whether the function modifies the members of the mutable struct or not. It might be he…

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## [Why this code does a segfault?](https://discourse.julialang.org/t/why-this-code-does-a-segfault/66394)

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**Author:** [@Lecrapouille](https://discourse.julialang.org/u/Lecrapouille)\
**Replies:** 21\
**Last updated:** [August 15, 2021, 11:46am UTC](https://discourse.julialang.org/t/why-this-code-does-a-segfault/66394 "2021-08-15T11:46:06Z")

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Why this code does a segfault ? foo.c #include \<stdio.h\> struct mystruct { int a; int b; }; typedef struct mystruct mystruct\_t; int recvstruct(mystruct\_t\* st) { printf("C %u, %u\\n", st-\>a, st-\>b); ret…

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## [Typing functions arguments representing tuples of custom structs](https://discourse.julialang.org/t/typing-functions-arguments-representing-tuples-of-custom-structs/66395)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 7\
**Last updated:** [August 15, 2021, 10:40am UTC](https://discourse.julialang.org/t/typing-functions-arguments-representing-tuples-of-custom-structs/66395 "2021-08-15T10:40:35Z")

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Hello, Considering the following struct: struct my\_struct{A \<: Function,B \<: Function} a::A b::B end I would like to write a function func that accepts an OrderedDict which values are Tuples of an unknown amou…

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## [Simple function to blur an image?](https://discourse.julialang.org/t/simple-function-to-blur-an-image/66417)

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**Author:** [@NHDaly](https://discourse.julialang.org/u/NHDaly)\
**Replies:** 4\
**Last updated:** [August 15, 2021, 9:53am UTC](https://discourse.julialang.org/t/simple-function-to-blur-an-image/66417 "2021-08-15T09:53:24Z")

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Hi all - today i found myself wanting to blur an image, and i figured it should be easy to find an example online. But I wasn’t able to find one… I’m sure that i’m just not searching for the right terms, because I am by…

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## [Julia + Jupyter notebooks in VSCodium?](https://discourse.julialang.org/t/julia-jupyter-notebooks-in-vscodium/66403)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 7\
**Last updated:** [August 14, 2021, 10:14pm UTC](https://discourse.julialang.org/t/julia-jupyter-notebooks-in-vscodium/66403 "2021-08-14T22:14:44Z")

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Hi. I’m not much for telemetry and such, so I’m trying to use VSCodium to work with Jupyter Notebooks running the Julia kernel. The VSCodium I’m using is the current up to date 1.59.0 AppImage download for Linux x64 VSC…

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## [Can FunctionWrappers.jl express higher order functions?](https://discourse.julialang.org/t/can-functionwrappers-jl-express-higher-order-functions/66404)

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**Author:** [@greatpet](https://discourse.julialang.org/u/greatpet)\
**Replies:** 2\
**Last updated:** [August 14, 2021, 9:56pm UTC](https://discourse.julialang.org/t/can-functionwrappers-jl-express-higher-order-functions/66404 "2021-08-14T21:56:10Z")

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I’m looking into FunctionWrappers.jl which provides functionality similar to function pointers in C and std::function in C++. Suppose a function accept two arguments, where the first argument has type Int, and the second…

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## [\[ANN\] SymmetryReduceBZ.jl: reduce the Brillouin zone by symmetry](https://discourse.julialang.org/t/ann-symmetryreducebz-jl-reduce-the-brillouin-zone-by-symmetry/64603)

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**Author:** [@jerjorg](https://discourse.julialang.org/u/jerjorg)\
**Replies:** 3\
**Last updated:** [August 14, 2021, 8:54pm UTC](https://discourse.julialang.org/t/ann-symmetryreducebz-jl-reduce-the-brillouin-zone-by-symmetry/64603 "2021-08-14T20:54:43Z")

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Calculating the properties of crystalline materials requires numeric integration. The function integrated is costly to evaluate, so symmetry is used to reduce the number of function evaluations. SymmetryReduceBZ.jl is a …

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## [LDLt factorization for sparse matrix](https://discourse.julialang.org/t/ldlt-factorization-for-sparse-matrix/57011)

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**Author:** [@nbakas](https://discourse.julialang.org/u/nbakas)\
**Replies:** 2\
**Last updated:** [August 14, 2021, 7:50pm UTC](https://discourse.julialang.org/t/ldlt-factorization-for-sparse-matrix/57011 "2021-08-14T19:50:27Z")

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I am trying to compute the LDLt factorization for sparse matrix, which is symmetric and positive definite, and get the L and D factors. I tried many things, but I don’t yet have a solution. For example, julia\> C=ldlt(x…

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## [Technical question about DelayEmbeddings.jl](https://discourse.julialang.org/t/technical-question-about-delayembeddings-jl/66057)

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**Author:** [@iamsuddhasattwa](https://discourse.julialang.org/u/iamsuddhasattwa)\
**Replies:** 12\
**Last updated:** [August 14, 2021, 5:18pm UTC](https://discourse.julialang.org/t/technical-question-about-delayembeddings-jl/66057 "2021-08-14T17:18:15Z")

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Hi, I was trying to use the DelayEmbeddings.jl package, and I am trying to find a means to obtain the optimal delay embedding parameters (tsu, DeltaT) for a given timeseries. However the documentation https://juliadynam…

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## [Mesh grid in Julia](https://discourse.julialang.org/t/mesh-grid-in-julia/66363)

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**Author:** [@Manisha\_07](https://discourse.julialang.org/u/Manisha_07)\
**Replies:** 10\
**Last updated:** [August 14, 2021, 2:08pm UTC](https://discourse.julialang.org/t/mesh-grid-in-julia/66363 "2021-08-14T14:08:38Z")

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Hello People I have been working on heat equation simulation using Julia Software. I was stuck with creating a surface plot (3d plotting) I have values of x,t and T (is a matrix) how to make 3d plot Please help me

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## [\[ANN\] Differential equations on manifolds: ManifoldDiffEq.jl](https://discourse.julialang.org/t/ann-differential-equations-on-manifolds-manifolddiffeq-jl/66385)

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**Author:** [@mateuszbaran](https://discourse.julialang.org/u/mateuszbaran)\
**Replies:** 3\
**Last updated:** [August 14, 2021, 1:46pm UTC](https://discourse.julialang.org/t/ann-differential-equations-on-manifolds-manifolddiffeq-jl/66385 "2021-08-14T13:46:38Z")

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We introduce the package ManifoldDiffEq.jl to solve differential equations on Riemannian manifolds. The package implements algorithms using interfaces of ManifoldsBase.jl and OrdinaryDiffEq.jl, combining strengths of bot…

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## [Video of "Writing fast sequential Julia Code" talk](https://discourse.julialang.org/t/video-of-writing-fast-sequential-julia-code-talk/66279)

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**Author:** [@Arrigo\_Benedetti](https://discourse.julialang.org/u/Arrigo_Benedetti)\
**Replies:** 1\
**Last updated:** [August 14, 2021, 12:10pm UTC](https://discourse.julialang.org/t/video-of-writing-fast-sequential-julia-code-talk/66279 "2021-08-14T12:10:07Z")

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I could not attend the talk entitled “Writing fast sequential Julia Code” by Simon Schoelly so I looked for the recording but I could not find it. I also contacted Simon Schoelly but have not heard from him yet. Also, t…

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## [\[ANN\] SQLdf - SQL for Julia types implementing Tables.jl](https://discourse.julialang.org/t/ann-sqldf-sql-for-julia-types-implementing-tables-jl/66380)

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**Author:** [@viraltux](https://discourse.julialang.org/u/viraltux)\
**Replies:** 0\
**Last updated:** [August 14, 2021, 8:35am UTC](https://discourse.julialang.org/t/ann-sqldf-sql-for-julia-types-implementing-tables-jl/66380 "2021-08-14T08:35:43Z")

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Latest version 0.2.0 of SQLdf uses as default RDB engine SQLite.jl instead accessing R/sqldf via RCall. This latest version and its default has the following new features: More responsive access to SQLite Ability to qu…

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## [Instructions for deploying Genie applications to virtual machine and container platform](https://discourse.julialang.org/t/instructions-for-deploying-genie-applications-to-virtual-machine-and-container-platform/66381)

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**Author:** [@jaantollander](https://discourse.julialang.org/u/jaantollander)\
**Replies:** 0\
**Last updated:** [August 14, 2021, 8:40am UTC](https://discourse.julialang.org/t/instructions-for-deploying-genie-applications-to-virtual-machine-and-container-platform/66381 "2021-08-14T08:40:37Z")

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Hello! During summer 2021, I have been working at CSC, testing their cloud computing resources from the user standpoint. First, I used the Genie framework to create a simple web application with a user interface and JSON…

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## [Multi-level varying slopes with two clusters, cross classification](https://discourse.julialang.org/t/multi-level-varying-slopes-with-two-clusters-cross-classification/62036)

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**Author:** [@Neal](https://discourse.julialang.org/u/Neal)\
**Replies:** 16\
**Last updated:** [August 14, 2021, 8:35am UTC](https://discourse.julialang.org/t/multi-level-varying-slopes-with-two-clusters-cross-classification/62036 "2021-08-14T08:35:26Z")

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Hello, I am working through StatisticalRethinking books with multi-level varying slopes with two clusters, cross classification model I run the stan model which finished sampling about two minutes. To build the mod…

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## [Why is Python, not Julia, still used for most state-of-the-art AI research?](https://discourse.julialang.org/t/why-is-python-not-julia-still-used-for-most-state-of-the-art-ai-research/45896)

<div class="topic-metadata">

**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 65\
**Last updated:** [August 14, 2021, 8:12am UTC](https://discourse.julialang.org/t/why-is-python-not-julia-still-used-for-most-state-of-the-art-ai-research/45896 "2021-08-14T08:12:25Z")

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I know e.g. ALBERTA, a variant of BERT, has been recreated in Julia, and AlphaZero, but all the (recent) papers I read, I see are still based on Python code, if the language is known to me (e.g. GPT-2 and updated GPT-3).…

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## [What would be an efficient image type to apply a series of JuliaImages filters?](https://discourse.julialang.org/t/what-would-be-an-efficient-image-type-to-apply-a-series-of-juliaimages-filters/66332)

<div class="topic-metadata">

**Author:** [@erwanlecarpentier](https://discourse.julialang.org/u/erwanlecarpentier)\
**Replies:** 4\
**Last updated:** [August 14, 2021, 8:11am UTC](https://discourse.julialang.org/t/what-would-be-an-efficient-image-type-to-apply-a-series-of-juliaimages-filters/66332 "2021-08-14T08:11:30Z")

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Hey! I am applying a series of filters/operations from JuliaImages to images that are initially of type Array{UInt8,2}. What would be the most efficient image type for this kind of computation? Should I always convert b…

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## [Julia says 0^0 = 1 while Python says it is 0. Who is right?](https://discourse.julialang.org/t/julia-says-0-0-1-while-python-says-it-is-0-who-is-right/66311)

<div class="topic-metadata">

**Author:** [@cybervigilante](https://discourse.julialang.org/u/cybervigilante)\
**Replies:** 7\
**Last updated:** [August 14, 2021, 5:20am UTC](https://discourse.julialang.org/t/julia-says-0-0-1-while-python-says-it-is-0-who-is-right/66311 "2021-08-14T05:20:14Z")

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julia: 0^0 = 1 Python: 0^0 = 0 Who is right? A plot shows where Python falls down: Y = \[x^x for x in 1:-.0001:.0001\] X = \[x for x in 1:-.0001:.0001\] using Plots plot(X,Y,title="Death curve of Python") println(minimu…

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