# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1320

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

**Page:** 1321

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## [JuliaReach workshop materials uploaded](https://discourse.julialang.org/t/juliareach-workshop-materials-uploaded/65291)

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**Author:** [@mforets](https://discourse.julialang.org/u/mforets)\
**Replies:** 0\
**Last updated:** [July 26, 2021, 6:47am UTC](https://discourse.julialang.org/t/juliareach-workshop-materials-uploaded/65291 "2021-07-26T06:47:21Z")

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We have uploaded the materials for our workshop It’s all Set: A hands-on introduction to JuliaReach. The notebooks can be found here: GitHub - JuliaReach/JuliaCon-2021-Workshop-Its-All-Set: It's all Set: A hands-on intr…

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## [Seeking Research Support On National Science Foundation Study](https://discourse.julialang.org/t/seeking-research-support-on-national-science-foundation-study/65289)

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**Author:** [@YummyPampers2](https://discourse.julialang.org/u/YummyPampers2)\
**Replies:** 0\
**Last updated:** [July 26, 2021, 5:19am UTC](https://discourse.julialang.org/t/seeking-research-support-on-national-science-foundation-study/65289 "2021-07-26T05:19:18Z")

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Hello Fellow Julians: We are seeking some research support on a health care research study we are submitting to NSF. We are canvassing the posting as an SDE+ (Software Development Engineer), but that is only becaus…

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## [Overwrite the subdataframes made with a for loop](https://discourse.julialang.org/t/overwrite-the-subdataframes-made-with-a-for-loop/65176)

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**Author:** [@bojusemo](https://discourse.julialang.org/u/bojusemo)\
**Replies:** 10\
**Last updated:** [July 26, 2021, 1:54am UTC](https://discourse.julialang.org/t/overwrite-the-subdataframes-made-with-a-for-loop/65176 "2021-07-26T01:54:42Z")

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Hi Guys, Could someone help me, please? I have a function with two dataframes (df1 and df2) as input that filter df1 based on a column that contains unique identifiers (IDs) and creates a subdataframe, makes a series o…

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## [About @connectors](https://discourse.julialang.org/t/about-connectors/65083)

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**Author:** [@juliascrub](https://discourse.julialang.org/u/juliascrub)\
**Replies:** 3\
**Last updated:** [July 26, 2021, 12:47am UTC](https://discourse.julialang.org/t/about-connectors/65083 "2021-07-26T00:47:08Z")

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Ive got a model defined as a connector @connector function Pin(iv::Num; name) ... end And another model composed of these connectors: function ModelWithConnectors(iv::Num; name) @named a = Pin(iv) @named b …

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## [Julia API design](https://discourse.julialang.org/t/julia-api-design/65285)

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**Author:** [@minetest2048](https://discourse.julialang.org/u/minetest2048)\
**Replies:** 1\
**Last updated:** [July 26, 2021, 12:26am UTC](https://discourse.julialang.org/t/julia-api-design/65285 "2021-07-26T00:26:16Z")

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I want to try to reimplement pyxivapi in Julia, which is client for XIVAPI REST API. But I don’t know how to write the Julia APIs that looks like Julia library. Julia feels very different than other programming languages…

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## [Generically iterating over arrays of points](https://discourse.julialang.org/t/generically-iterating-over-arrays-of-points/65273)

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**Author:** [@dfarmer](https://discourse.julialang.org/u/dfarmer)\
**Replies:** 3\
**Last updated:** [July 25, 2021, 9:42pm UTC](https://discourse.julialang.org/t/generically-iterating-over-arrays-of-points/65273 "2021-07-25T21:42:41Z")

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I’m trying to write some functions that work on arrays of 2d or 3d points, so generally speaking I’m planning to use Vector{SVector{3,T}} but I would like to make the functions generic enough to handle a 3xN matrix form …

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## [Julia 1.6.2 weird installation: launches 1.6.0 instead of 1.6.2 \[SOLVED\]](https://discourse.julialang.org/t/julia-1-6-2-weird-installation-launches-1-6-0-instead-of-1-6-2-solved/65263)

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**Author:** [@mocalvao](https://discourse.julialang.org/u/mocalvao)\
**Replies:** 5\
**Last updated:** [July 25, 2021, 9:18pm UTC](https://discourse.julialang.org/t/julia-1-6-2-weird-installation-launches-1-6-0-instead-of-1-6-2-solved/65263 "2021-07-25T21:18:22Z")

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Hi there, Forgive me if I am doing something very silly, but I have downloaded version 1.6.2 from: https://julialang-s3.julialang.org/bin/linux/x64/1.6/julia-1.6.2-linux-x86\_64.tar.gz and installed it by simply decomp…

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## [\[ANN\] Announcing AlgebraPDF.jl - operations on functions with parameters](https://discourse.julialang.org/t/ann-announcing-algebrapdf-jl-operations-on-functions-with-parameters/65213)

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**Author:** [@misha\_mikhasenko](https://discourse.julialang.org/u/misha_mikhasenko)\
**Replies:** 12\
**Last updated:** [July 25, 2021, 8:53pm UTC](https://discourse.julialang.org/t/ann-announcing-algebrapdf-jl-operations-on-functions-with-parameters/65213 "2021-07-25T20:53:44Z")

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Hi, I am happy to announce AlgebraPDF.jl, a package that defines operations on parametric functions and keeps track of parameters. f1 = FunctionWithParameters((x;p)-\>cos(p.a\*x+p.b), (a=5.0, b=2.0)) f2 = FunctionWithPar…

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## [Excel data to dataframes](https://discourse.julialang.org/t/excel-data-to-dataframes/65264)

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**Author:** [@mjanun](https://discourse.julialang.org/u/mjanun)\
**Replies:** 16\
**Last updated:** [July 25, 2021, 7:21pm UTC](https://discourse.julialang.org/t/excel-data-to-dataframes/65264 "2021-07-25T19:21:39Z")

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I have some data in different columns of an Excel sheet. I want to read the different columns into separate dataframes. I know the the column name/number where the data for each dataframe starts but not number of rows of…

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## [About DataFrame(array\_of\_dict)](https://discourse.julialang.org/t/about-dataframe-array-of-dict/65253)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 5\
**Last updated:** [July 25, 2021, 6:45pm UTC](https://discourse.julialang.org/t/about-dataframe-array-of-dict/65253 "2021-07-25T18:45:30Z")

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using AlphaVantage, DataFrames apikey\_AV = AlphaVantage.global\_key!("5J16OULI0KY026M4"); tickerList = \["AAPL","MSFT"\]; StockHistoryRawJson = AlphaVantage.time\_series\_daily\_adjusted.(Stocks.tickerList, outputsize="compac…

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## [Replacing missings based on values in two DataFrame columns](https://discourse.julialang.org/t/replacing-missings-based-on-values-in-two-dataframe-columns/64764)

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**Author:** [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Replies:** 1\
**Last updated:** [July 16, 2021, 6:01pm UTC](https://discourse.julialang.org/t/replacing-missings-based-on-values-in-two-dataframe-columns/64764 "2021-07-16T18:01:27Z")

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Given an input table like this: Row │ x y z │ Int64 Int64 Int64? ─────┼─────────────────────── 1 │ 100 1 missing 2 │ 101 1 missing 3 │ 102 1 missing 4 │ …

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## [Avoiding memory allocation when repeatedly using small arrays](https://discourse.julialang.org/t/avoiding-memory-allocation-when-repeatedly-using-small-arrays/65261)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 5\
**Last updated:** [July 25, 2021, 5:13pm UTC](https://discourse.julialang.org/t/avoiding-memory-allocation-when-repeatedly-using-small-arrays/65261 "2021-07-25T17:13:11Z")

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I often find myself needing fairly simple, small autodiff vector operations applied repeatedly. I don’t know how to do this without allocation each time. Is it possible? Here is an example where I’m integrating an array…

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## [Filter and filter! give different results](https://discourse.julialang.org/t/filter-and-filter-give-different-results/65271)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 2\
**Last updated:** [July 25, 2021, 5:11pm UTC](https://discourse.julialang.org/t/filter-and-filter-give-different-results/65271 "2021-07-25T17:11:42Z")

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I am wondering why filter and filter! give different results in the example below. Case 1 with filter! includes an extra element whereas Case 2 with filter works as expected mutable struct M x::Int y::Int end C…

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## [Selectively unpacking binary data](https://discourse.julialang.org/t/selectively-unpacking-binary-data/64768)

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**Author:** [@Mikhail\_Kagalenko](https://discourse.julialang.org/u/Mikhail_Kagalenko)\
**Replies:** 1\
**Last updated:** [July 25, 2021, 11:08am UTC](https://discourse.julialang.org/t/selectively-unpacking-binary-data/64768 "2021-07-25T11:08:57Z")

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I need to unpack a few values of known types and offsets from a binary file. The difference with earlier discussed cases is, firstly, that the values are not adjacent in the file, so it is necessary to specify offsefs; …

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## [Different @code\_warntype behavior depending on number of fileds in 'struct'](https://discourse.julialang.org/t/different-code-warntype-behavior-depending-on-number-of-fileds-in-struct/65259)

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**Author:** [@sidelkin](https://discourse.julialang.org/u/sidelkin)\
**Replies:** 2\
**Last updated:** [July 25, 2021, 3:54pm UTC](https://discourse.julialang.org/t/different-code-warntype-behavior-depending-on-number-of-fileds-in-struct/65259 "2021-07-25T15:54:34Z")

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Hello. When the number of fields in a struct is less than 15, @code\_warntype diagnoses that the function is ‘type-stable’. But as their number grows, the function becomes ‘type-unstable’ from @code\_warntype’s point of v…

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## [Sparse Feed Forward NN](https://discourse.julialang.org/t/sparse-feed-forward-nn/33203)

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**Author:** [@olszewskip](https://discourse.julialang.org/u/olszewskip)\
**Replies:** 3\
**Last updated:** [July 25, 2021, 1:27pm UTC](https://discourse.julialang.org/t/sparse-feed-forward-nn/33203 "2021-07-25T13:27:10Z")

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Hi! I have a question about (hypothetical) sparse layers in feedforward neural neworks: How would I go about using sparse array in place of W(eights) and b(iases) in the Flux’es Dense layer? What I imagine is that I hav…

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## [Unitful.jl: State of the units](https://discourse.julialang.org/t/unitful-jl-state-of-the-units/1530)

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**Author:** [@ajkeller34](https://discourse.julialang.org/u/ajkeller34)\
**Replies:** 0\
**Last updated:** [January 17, 2017, 1:55am UTC](https://discourse.julialang.org/t/unitful-jl-state-of-the-units/1530 "2017-01-17T01:55:00Z")

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Unitful.jl, a package for manipulating unitful quantities, has recently undergone some extensive changes on the master branch aimed at improving the defaults system and achieving compatibility with the upcoming Julia 0.6…

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## [Using Pixel buffer objects to update textures in OpenGl](https://discourse.julialang.org/t/using-pixel-buffer-objects-to-update-textures-in-opengl/65260)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 0\
**Last updated:** [July 25, 2021, 11:25am UTC](https://discourse.julialang.org/t/using-pixel-buffer-objects-to-update-textures-in-opengl/65260 "2021-07-25T11:25:05Z")

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Hello I looked into GL/GLAbstraction.jl package and as far as I see texture updating is done by glTexSubImage2D , yet why Pixel buffer objects are not used? Is there some reason? Frankly I tried to implement the pixel b…

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## [How apply Subtraction operator to extrema() function](https://discourse.julialang.org/t/how-apply-subtraction-operator-to-extrema-function/65255)

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**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 1\
**Last updated:** [July 25, 2021, 8:29am UTC](https://discourse.julialang.org/t/how-apply-subtraction-operator-to-extrema-function/65255 "2021-07-25T08:29:22Z")

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How apply Subtraction operator to extrema() function julia\> extrema(2:10) (2, 10) julia\> -(2,10) -8 julia\> -extrema(2:10) ERROR: MethodError: no method matching -(::Tuple{Int64, Int64}) Closest candidates are: -(::Un…

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## [Unable to verify \`eigen(A)\`](https://discourse.julialang.org/t/unable-to-verify-eigen-a/65249)

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**Author:** [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Replies:** 1\
**Last updated:** [July 25, 2021, 1:26am UTC](https://discourse.julialang.org/t/unable-to-verify-eigen-a/65249 "2021-07-25T01:26:42Z")

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I haven’t had my coffee yet, but it seems like following should return true. Where did I get turned around? using LinearAlgebra A = rand(5, 5) Λ, Y = eigen(A) Λ = Diagonal(Λ) A \* Y ≈ Λ \* Y

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## [What's the deal with that "\[ANN\]" stuff in titles in Package announcements?](https://discourse.julialang.org/t/whats-the-deal-with-that-ann-stuff-in-titles-in-package-announcements/57425)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 11\
**Last updated:** [July 25, 2021, 12:50am UTC](https://discourse.julialang.org/t/whats-the-deal-with-that-ann-stuff-in-titles-in-package-announcements/57425 "2021-07-25T00:50:50Z")

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I guess it stands for (package) ANNouncement? Although, the first time I saw it I thought it referred to a lady named Ann… What is the purpose of putting it in a thread’s title? I see that not all package announcement t…

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## [Naive dot product faster in Fortran than in Juila](https://discourse.julialang.org/t/naive-dot-product-faster-in-fortran-than-in-juila/63317)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 12\
**Last updated:** [July 24, 2021, 11:03pm UTC](https://discourse.julialang.org/t/naive-dot-product-faster-in-fortran-than-in-juila/63317 "2021-07-24T23:03:42Z")

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Does anyone knows why this simple dot product is faster in Fortran then in Julia? (LinearAlgebra.dot is faster and with LoopVectorization the Julia code gets also faster. but this is not what I am questioning. I am curi…

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## [Parse string as tuple](https://discourse.julialang.org/t/parse-string-as-tuple/65244)

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**Author:** [@mjanun](https://discourse.julialang.org/u/mjanun)\
**Replies:** 5\
**Last updated:** [July 24, 2021, 10:34pm UTC](https://discourse.julialang.org/t/parse-string-as-tuple/65244 "2021-07-24T22:34:10Z")

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I am trying to write a function that converts a string to a tuple. This is my code: parsetuple(p::String) = Tuple(Float64(x) for x in p) This code can convert a string or a vector of string type to a tuple, but this do…

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## [How to unpack a vector to a struct / local variables](https://discourse.julialang.org/t/how-to-unpack-a-vector-to-a-struct-local-variables/65241)

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**Author:** [@lamont](https://discourse.julialang.org/u/lamont)\
**Replies:** 5\
**Last updated:** [July 24, 2021, 8:05pm UTC](https://discourse.julialang.org/t/how-to-unpack-a-vector-to-a-struct-local-variables/65241 "2021-07-24T20:05:27Z")

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Is there a better way to write a function like this (which is called from an integrator so needs to have dx and x being Vector{Float64}'s and unpack them without excessive copying and mostly without all the magic numeric…

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## [Transforming an Array{Matrix{T, N}, M} to an Array{T, N+M}](https://discourse.julialang.org/t/transforming-an-array-matrix-t-n-m-to-an-array-t-n-m/65192)

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**Author:** [@mmaeusezahl](https://discourse.julialang.org/u/mmaeusezahl)\
**Replies:** 10\
**Last updated:** [July 24, 2021, 3:29pm UTC](https://discourse.julialang.org/t/transforming-an-array-matrix-t-n-m-to-an-array-t-n-m/65192 "2021-07-24T15:29:27Z")

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Hi, usually I had a lot of success discovering the various ways to transform the Array datatypes into each other but this one gives me some headaches: From a parallelized operation I end up with an array (with an arbitr…

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## [First order ODE with input delay](https://discourse.julialang.org/t/first-order-ode-with-input-delay/65231)

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**Author:** [@Fabian](https://discourse.julialang.org/u/Fabian)\
**Replies:** 1\
**Last updated:** [July 24, 2021, 7:18pm UTC](https://discourse.julialang.org/t/first-order-ode-with-input-delay/65231 "2021-07-24T19:18:05Z")

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Hi, I am new to Julia / Turing.jl and wondering if it is possible to estimate the affine parameters a,b of the following model. The model is a stochastic differential equation (SDE) of first order with variable input d…

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## [Confusion with eachrow and pipe](https://discourse.julialang.org/t/confusion-with-eachrow-and-pipe/65237)

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**Author:** [@drbenvincent](https://discourse.julialang.org/u/drbenvincent)\
**Replies:** 8\
**Last updated:** [July 24, 2021, 5:17pm UTC](https://discourse.julialang.org/t/confusion-with-eachrow-and-pipe/65237 "2021-07-24T17:17:50Z")

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Let’s say we have a simple 2D matrix a = \[0 1 2 3 4; 5 6 7 8 9; 10 11 12 13 14; 15 16 17 18 19\] map It looks like you can apply a function to rows and columns like this julia\> map(sum, eachrow(a)) 4-elem…

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## [JuMP is slow in generating block PSD constraints](https://discourse.julialang.org/t/jump-is-slow-in-generating-block-psd-constraints/65186)

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**Author:** [@Thomas](https://discourse.julialang.org/u/Thomas)\
**Replies:** 2\
**Last updated:** [July 24, 2021, 2:48pm UTC](https://discourse.julialang.org/t/jump-is-slow-in-generating-block-psd-constraints/65186 "2021-07-24T14:48:41Z")

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Could an expert help me speed up the following code? In particular, Have I used the performance tips (https://jump.dev/JuMP.jl/stable/tutorials/Getting%20started/performance\_tips/) correctly? That is only generate exp…

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## [How to check \`-O\` optimization flag setting inside script?](https://discourse.julialang.org/t/how-to-check-o-optimization-flag-setting-inside-script/65233)

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**Author:** [@johnomotani](https://discourse.julialang.org/u/johnomotani)\
**Replies:** 2\
**Last updated:** [July 24, 2021, 2:05pm UTC](https://discourse.julialang.org/t/how-to-check-o-optimization-flag-setting-inside-script/65233 "2021-07-24T14:05:01Z")

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I’m writing a script to run a performance benchmark. I’d like to add a check that Julia is running with full optimization (i.e. -O3) to ensure the results are representative. Is there a way to get the -O optimization fla…

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## [How do I know if an unbuffered (0 sized) channel ready to put! (not blocking)?](https://discourse.julialang.org/t/how-do-i-know-if-an-unbuffered-0-sized-channel-ready-to-put-not-blocking/65228)

<div class="topic-metadata">

**Author:** [@zwtechnb](https://discourse.julialang.org/u/zwtechnb)\
**Replies:** 0\
**Last updated:** [July 24, 2021, 10:43am UTC](https://discourse.julialang.org/t/how-do-i-know-if-an-unbuffered-0-sized-channel-ready-to-put-not-blocking/65228 "2021-07-24T10:43:48Z")

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For a buffered channel(n) with n\>0, I can check it full or not with comparing the Channel field: sz\_max with the undocumented function Base.n\_avail(channel). For channel(0), when a take! on it, a put! can be operated on…

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