# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1764

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

**Page:** 1765

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## [Improving an algorithm that compute gps distances](https://discourse.julialang.org/t/improving-an-algorithm-that-compute-gps-distances/38213)

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**Author:** [@David\_Cardozo](https://discourse.julialang.org/u/David_Cardozo)\
**Replies:** 41\
**Last updated:** [April 27, 2020, 10:20am UTC](https://discourse.julialang.org/t/improving-an-algorithm-that-compute-gps-distances/38213 "2020-04-27T10:20:34Z")

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Hi everyone! Is it possible to parallelize vectorized functions / operations? I have this code I ported from python but it running a little bit slower than numpy and not surprisingly 10x slower than jax (cpu only). u…

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## [Changing grid in Plots.jl?](https://discourse.julialang.org/t/changing-grid-in-plots-jl/38232)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 4\
**Last updated:** [April 27, 2020, 8:42am UTC](https://discourse.julialang.org/t/changing-grid-in-plots-jl/38232 "2020-04-27T08:42:43Z")

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Hello! Basically I have something like this: I want to make it into something like this, where the grey grid lines (so I want them removed as well) are replaced with the black ones I drew in paint: Whenever I se…

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## [Choosing variables to plot from DifferentialEquations solution](https://discourse.julialang.org/t/choosing-variables-to-plot-from-differentialequations-solution/38252)

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**Author:** [@Eris](https://discourse.julialang.org/u/Eris)\
**Replies:** 0\
**Last updated:** [April 26, 2020, 6:21pm UTC](https://discourse.julialang.org/t/choosing-variables-to-plot-from-differentialequations-solution/38252 "2020-04-26T18:21:29Z")

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I understand that vrs is used in order to choose the variables to be plotted. i.e. in this example I plotted x vs y using DifferentialEquations, ParameterizedFunctions, Plots attrac = @ode\_def begin dx = σy dy = ρ(y…

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## [Find types of arguments of a function's method](https://discourse.julialang.org/t/find-types-of-arguments-of-a-functions-method/38257)

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**Author:** [@Albert\_Zevelev](https://discourse.julialang.org/u/Albert_Zevelev)\
**Replies:** 4\
**Last updated:** [April 27, 2020, 7:55am UTC](https://discourse.julialang.org/t/find-types-of-arguments-of-a-functions-method/38257 "2020-04-27T07:55:09Z")

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Suppose I wanna compute the mean of every distribution in Distributions.jl. I create a vector w/ all distributions then loop through each & compute the mean. Thanks to @tfehring for showing me how to pull all the distr…

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## [Parse Python3 code string to Julia akin to Numba/JIT compilers](https://discourse.julialang.org/t/parse-python3-code-string-to-julia-akin-to-numba-jit-compilers/38231)

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**Author:** [@Bjorn\_Madsen](https://discourse.julialang.org/u/Bjorn_Madsen)\
**Replies:** 7\
**Last updated:** [April 27, 2020, 6:45am UTC](https://discourse.julialang.org/t/parse-python3-code-string-to-julia-akin-to-numba-jit-compilers/38231 "2020-04-27T06:45:41Z")

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Forgive me if I’m catching up here, but I just started with Julia about 4 months ago. I hope this question falls into the tooling category. I have a special interest parsing Python code and turning it into Julia, such …

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## [Unit testing that depends on random number generation](https://discourse.julialang.org/t/unit-testing-that-depends-on-random-number-generation/38187)

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**Author:** [@colintbowers](https://discourse.julialang.org/u/colintbowers)\
**Replies:** 8\
**Last updated:** [April 27, 2020, 6:38am UTC](https://discourse.julialang.org/t/unit-testing-that-depends-on-random-number-generation/38187 "2020-04-27T06:38:19Z")

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I have a package, DependentBootstrap, where the unit tests rely explicitly on values generated by randn. Currently, I set the seed before each test to ensure each run is identical. Of course, this runs into problems when…

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## [Improvement for function chaining operator](https://discourse.julialang.org/t/improvement-for-function-chaining-operator/38283)

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**Author:** [@govorunov](https://discourse.julialang.org/u/govorunov)\
**Replies:** 6\
**Last updated:** [April 27, 2020, 6:04am UTC](https://discourse.julialang.org/t/improvement-for-function-chaining-operator/38283 "2020-04-27T06:04:46Z")

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Dear Julia founders and maintainers, please consider changing the function chaining (piping) operator to accept call specifications. The new syntax, as I see it would look like: var \>. callable(opt\_param1, opt\_param2) a…

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## [Reworking Distributions.jl](https://discourse.julialang.org/t/reworking-distributions-jl/32339)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 51\
**Last updated:** [April 27, 2020, 2:33am UTC](https://discourse.julialang.org/t/reworking-distributions-jl/32339 "2020-04-27T02:33:35Z")

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Hello all, I’ve been thinking some more about a refactoring of Distributions.jl, and I’d like to ask for feedback on a proof of concept. First, the abstract types: abstract type Sampleable{P,X} end abstract type Dist…

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## [Zygote: mutating array error with Buffer during parameter gradient call](https://discourse.julialang.org/t/zygote-mutating-array-error-with-buffer-during-parameter-gradient-call/38269)

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**Author:** [@ahl](https://discourse.julialang.org/u/ahl)\
**Replies:** 0\
**Last updated:** [April 27, 2020, 12:51am UTC](https://discourse.julialang.org/t/zygote-mutating-array-error-with-buffer-during-parameter-gradient-call/38269 "2020-04-27T00:51:42Z")

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I’m trying to update the parameters of a multi-input multi-output neural network using a loss function that is some function of the Jacobian of the neural network. However, computing the gradient of the loss produces an …

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## [On-the-fly Animation in IJulia Notebooks](https://discourse.julialang.org/t/on-the-fly-animation-in-ijulia-notebooks/524)

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**Author:** [@cortner](https://discourse.julialang.org/u/cortner)\
**Replies:** 45\
**Last updated:** [April 27, 2020, 1:25am UTC](https://discourse.julialang.org/t/on-the-fly-animation-in-ijulia-notebooks/524 "2020-04-27T01:25:21Z")

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I recently revisited how to do on-the-fly visualisation in an IJulia notebook, i.e., plotting results while the computation is still running. This was discussed a while back in Google groups link I’ve tried the same sch…

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## [Variable scope in IJulia Jupyter notebook](https://discourse.julialang.org/t/variable-scope-in-ijulia-jupyter-notebook/38264)

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**Author:** [@Ken\_Lin](https://discourse.julialang.org/u/Ken_Lin)\
**Replies:** 2\
**Last updated:** [April 27, 2020, 12:57am UTC](https://discourse.julialang.org/t/variable-scope-in-ijulia-jupyter-notebook/38264 "2020-04-27T00:57:26Z")

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I’m using Jupyter notebook by doing: using IJulia notebook() Now, if I try the following code: a = 1 for i = 1:2 a = a+1 end and the value of a would be 3. Isn’t it supposed to be an error as for loop can not mod…

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## [Creating a type from a Symbol inside a macro of a submodule?](https://discourse.julialang.org/t/creating-a-type-from-a-symbol-inside-a-macro-of-a-submodule/38247)

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**Author:** [@tamasgal](https://discourse.julialang.org/u/tamasgal)\
**Replies:** 3\
**Last updated:** [April 26, 2020, 11:48pm UTC](https://discourse.julialang.org/t/creating-a-type-from-a-symbol-inside-a-macro-of-a-submodule/38247 "2020-04-26T23:48:00Z")

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I am sorry if this is trivial, but I am trying to access the fields of a type, which is passed as a Symbol to a macro inside a submodule (in an imported one). Here is what I mean: struct Foo end ​ macro macro1(ex) …

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## [Error when using a PackageCompiler sys image in a different container](https://discourse.julialang.org/t/error-when-using-a-packagecompiler-sys-image-in-a-different-container/38074)

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**Author:** [@mmiller](https://discourse.julialang.org/u/mmiller)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 10:59pm UTC](https://discourse.julialang.org/t/error-when-using-a-packagecompiler-sys-image-in-a-different-container/38074 "2020-04-26T22:59:05Z")

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Hi, I’m getting the following error when trying to use a system image in a Python 3.8 container (with Julia installed). The system image was built using the Julia 1.4.1 docker image, using PackageCompiler ( incremental=…

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## [Fast implementations of integrodifference equations?](https://discourse.julialang.org/t/fast-implementations-of-integrodifference-equations/38265)

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**Author:** [@peterj](https://discourse.julialang.org/u/peterj)\
**Replies:** 0\
**Last updated:** [April 26, 2020, 9:50pm UTC](https://discourse.julialang.org/t/fast-implementations-of-integrodifference-equations/38265 "2020-04-26T21:50:37Z")

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Are there any libraries which have fast implementations of integrodifference equations? These are discrete time, continuous space dynamical systems used a lot in mathematical ecology where diffusion is replaced by integ…

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## [Show off Julia performance on your PC!](https://discourse.julialang.org/t/show-off-julia-performance-on-your-pc/33606)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 53\
**Last updated:** [April 26, 2020, 9:21pm UTC](https://discourse.julialang.org/t/show-off-julia-performance-on-your-pc/33606 "2020-04-26T21:21:39Z")

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I just built a new PC and, after asking some questions here about performance and getting some interesting answers, I thought it would be fun to start a thread where people can show off their builds and, more importantly…

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## [Scope of @time](https://discourse.julialang.org/t/scope-of-time/38261)

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**Author:** [@Ken\_Lin](https://discourse.julialang.org/u/Ken_Lin)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 9:18pm UTC](https://discourse.julialang.org/t/scope-of-time/38261 "2020-04-26T21:18:15Z")

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Is the scope of @time supposed to be local? If I do the following: x = 1 @time x = 2 Then the value of x will be 2. Why can I modify the value of a global variable x in a local scope @time? Similarly, I can declare v…

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## [Block sparse matrix multiplication with repeated blocks](https://discourse.julialang.org/t/block-sparse-matrix-multiplication-with-repeated-blocks/38107)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 4\
**Last updated:** [April 26, 2020, 6:51pm UTC](https://discourse.julialang.org/t/block-sparse-matrix-multiplication-with-repeated-blocks/38107 "2020-04-26T18:51:09Z")

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I’m trying to find a good way to compute V^TAV where A is a sparse CSC matrix A and V = I \\otimes B is a block diagonal matrix with repeating dense blocks (size of B is around \\mathbb{R}^{20 \\times 10}). Looping through…

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## [Include debug symbols in sysimage from PackageCompiler.jl?](https://discourse.julialang.org/t/include-debug-symbols-in-sysimage-from-packagecompiler-jl/38034)

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**Author:** [@OliverEvans96](https://discourse.julialang.org/u/OliverEvans96)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 6:25pm UTC](https://discourse.julialang.org/t/include-debug-symbols-in-sysimage-from-packagecompiler-jl/38034 "2020-04-26T18:25:11Z")

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I’m attempting to use PackageCompiler.jl to produce a .so containing Julia functions that can be called directly from C (after some julia initialization in the C code), as suggested by @kristoffer.carlsson in this githu…

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## [Precompiling of parametric constructors](https://discourse.julialang.org/t/precompiling-of-parametric-constructors/38243)

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**Author:** [@Isaia\_Nisoli](https://discourse.julialang.org/u/Isaia_Nisoli)\
**Replies:** 1\
**Last updated:** [April 26, 2020, 5:07pm UTC](https://discourse.julialang.org/t/precompiling-of-parametric-constructors/38243 "2020-04-26T17:07:31Z")

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Dear all, I am trying to implement some variable tracking types in a package colled DiffCheckNumbers.jl. The main issue I’m facing now is the slowdown that is generated by the compilation of the constructors. struct D…

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## [How to query key presses](https://discourse.julialang.org/t/how-to-query-key-presses/38242)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 1\
**Last updated:** [April 26, 2020, 4:51pm UTC](https://discourse.julialang.org/t/how-to-query-key-presses/38242 "2020-04-26T16:51:24Z")

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Is there a library which is able to query if a key is currently being pressed or not? I guess this would usually be done using OS-specific calls. The goal would be to detect multiple simultaneous key presses of a keybo…

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## [Embedding Julia in C](https://discourse.julialang.org/t/embedding-julia-in-c/23931)

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**Author:** [@Josiah\_Slack](https://discourse.julialang.org/u/Josiah_Slack)\
**Replies:** 7\
**Last updated:** [April 26, 2020, 3:45pm UTC](https://discourse.julialang.org/t/embedding-julia-in-c/23931 "2020-04-26T15:45:00Z")

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I recently created a topic called “Calling my own Julia module from C”, asking a nuts and bolts question about a use case that wasn’t covered by the documentation. I haven’t given up hope on getting an answer, but I thou…

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## [Simplifying simulation by clusters](https://discourse.julialang.org/t/simplifying-simulation-by-clusters/35870)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 18\
**Last updated:** [April 26, 2020, 3:10pm UTC](https://discourse.julialang.org/t/simplifying-simulation-by-clusters/35870 "2020-04-26T15:10:01Z")

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This is partly a question asking for recommendations on an algorithm, ideally something that is implemented some Julia package, or can be done simply using one. I am simulating a process in \\mathbb{R}^3 (I can constrai…

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## [Julia against Maple](https://discourse.julialang.org/t/julia-against-maple/38238)

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**Author:** [@ameresv](https://discourse.julialang.org/u/ameresv)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 2:58pm UTC](https://discourse.julialang.org/t/julia-against-maple/38238 "2020-04-26T14:58:22Z")

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Hi! More than a question, I am looking for a piece of advice for a project that I have. Most of the optimization and equations that I have to resolve for my paper requires the usage of Maple. However, is there a way to …

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## [Extend a varargs function for mixed types](https://discourse.julialang.org/t/extend-a-varargs-function-for-mixed-types/38233)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 2:57pm UTC](https://discourse.julialang.org/t/extend-a-varargs-function-for-mixed-types/38233 "2020-04-26T14:57:51Z")

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Is it possible to specialize on a varargs function if at least one of the arguments is of a certain type? Maybe best explained with an MWE: # Assume this is defined in another package which the code below depends on j…

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## [Add brackets after autocompleting a function](https://discourse.julialang.org/t/add-brackets-after-autocompleting-a-function/36545)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 1\
**Last updated:** [April 26, 2020, 2:55pm UTC](https://discourse.julialang.org/t/add-brackets-after-autocompleting-a-function/36545 "2020-04-26T14:55:58Z")

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So I recently updated from a JuliaPro 1.2 installation by downloading Julia 1.4 and atom separately, and the juno-packages after. There is a feature in the JuliaPro installation where if there is a function func(x), and …

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## [Type and methods info in macro](https://discourse.julialang.org/t/type-and-methods-info-in-macro/38199)

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**Author:** [@bpou](https://discourse.julialang.org/u/bpou)\
**Replies:** 0\
**Last updated:** [April 25, 2020, 4:40pm UTC](https://discourse.julialang.org/t/type-and-methods-info-in-macro/38199 "2020-04-25T16:40:01Z")

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Hello, I’ve been attempting to implement a simple APL in julia. Something similar has been done here: https://github.com/shashi/APL.jl, but that is an interpreter. I wanted to do it as a syntax transformation to use as …

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## [The state of cryptographic libraries](https://discourse.julialang.org/t/the-state-of-cryptographic-libraries/29724)

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**Author:** [@Janis\_Erdmanis](https://discourse.julialang.org/u/Janis_Erdmanis)\
**Replies:** 19\
**Last updated:** [April 26, 2020, 8:08am UTC](https://discourse.julialang.org/t/the-state-of-cryptographic-libraries/29724 "2020-04-26T08:08:57Z")

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Hello, everyone! For my next project, I need hashing and public-key cryptography. What are the options currently available in the Julia ecosystem to get those things? Also, I need a secure messaging system within Julia…

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## [Why summary(T::Tuple) is the same as string(T::Tuple) after Julia 1.3?](https://discourse.julialang.org/t/why-summary-t-tuple-is-the-same-as-string-t-tuple-after-julia-1-3/38220)

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**Author:** [@Jieyi\_Xiong](https://discourse.julialang.org/u/Jieyi_Xiong)\
**Replies:** 1\
**Last updated:** [April 26, 2020, 8:04am UTC](https://discourse.julialang.org/t/why-summary-t-tuple-is-the-same-as-string-t-tuple-after-julia-1-3/38220 "2020-04-26T08:04:23Z")

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Before Julia 1.3 julia\> summary((collect(1:100), )) "Tuple{Array{Int64,1}}" After Julia 1.3 julia\> summary((collect(1:100), )) "(\[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, …

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## [Manually specialized function is faster than the generic version](https://discourse.julialang.org/t/manually-specialized-function-is-faster-than-the-generic-version/38223)

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**Author:** [@fjarri](https://discourse.julialang.org/u/fjarri)\
**Replies:** 2\
**Last updated:** [April 26, 2020, 6:58am UTC](https://discourse.julialang.org/t/manually-specialized-function-is-faster-than-the-generic-version/38223 "2020-04-26T06:58:36Z")

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The code: using BenchmarkTools function adc(a::T, b::T, carry::T) where T T2 = widen(T) ret = (a % T2) + (b % T2) + (carry % T2) ret % T, (ret \>\> 64) % T end function mac(a::T, b::T, c::T, carry::T) wher…

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## [How to make TCP socket listening more robust to errors?](https://discourse.julialang.org/t/how-to-make-tcp-socket-listening-more-robust-to-errors/38184)

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**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 1\
**Last updated:** [April 26, 2020, 6:52am UTC](https://discourse.julialang.org/t/how-to-make-tcp-socket-listening-more-robust-to-errors/38184 "2020-04-26T06:52:03Z")

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I’ve written a simple package for evaluating functions and passing data between Julia processes using TCP sockets. It works pretty well, as long as the function evaluations don’t produce any errors. If the an error occ…

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