# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1424

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

**Page:** 1425

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## [Exact numerical logging](https://discourse.julialang.org/t/exact-numerical-logging/58766)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 25\
**Last updated:** [April 15, 2021, 4:05pm UTC](https://discourse.julialang.org/t/exact-numerical-logging/58766 "2021-04-15T16:05:12Z")

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I have a long-running calculation, for which want to emit a log that allows recovery of exact numerical values, so that I can restart or debug the calculation. The typical logged item can be thought of as a (possibly nes…

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## [Why use subtypes instead of traits and duck typing?](https://discourse.julialang.org/t/why-use-subtypes-instead-of-traits-and-duck-typing/59146)

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**Author:** [@regier2302](https://discourse.julialang.org/u/regier2302)\
**Replies:** 32\
**Last updated:** [April 15, 2021, 3:58pm UTC](https://discourse.julialang.org/t/why-use-subtypes-instead-of-traits-and-duck-typing/59146 "2021-04-15T15:58:50Z")

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I have been tinkering with Julia and I am now trying to design a moderate-sized project. However, I have been struggling to come up with a type hierarchy and I realized that, in Julia, I don’t know why you should subtype…

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## [When should things be equal?](https://discourse.julialang.org/t/when-should-things-be-equal/59345)

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**Author:** [@jonniedie](https://discourse.julialang.org/u/jonniedie)\
**Replies:** 3\
**Last updated:** [April 15, 2021, 3:15pm UTC](https://discourse.julialang.org/t/when-should-things-be-equal/59345 "2021-04-15T15:15:41Z")

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There is some useful (at least for me) discussion between @marius311 and I on this issue about when equality should hold between things. It was a little surprising to me that in general A == B between two arrays always…

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## [Performance difference between optional args and keyword args](https://discourse.julialang.org/t/performance-difference-between-optional-args-and-keyword-args/59272)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 8\
**Last updated:** [April 15, 2021, 2:26pm UTC](https://discourse.julialang.org/t/performance-difference-between-optional-args-and-keyword-args/59272 "2021-04-15T14:26:30Z")

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Is there any (theoretical) difference in performance between functions defined with optional arguments and functions defined with keyword arguments? The manual says: Keyword arguments behave quite differently from ordi…

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## [Modifying object dict keys](https://discourse.julialang.org/t/modifying-object-dict-keys/59266)

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**Author:** [@mkamensky](https://discourse.julialang.org/u/mkamensky)\
**Replies:** 9\
**Last updated:** [April 15, 2021, 2:24pm UTC](https://discourse.julialang.org/t/modifying-object-dict-keys/59266 "2021-04-15T14:24:16Z")

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Hi, I’m doing foo=\[1\] bar=Dict(foo =\> 2) push!(foo, 3) what I was expecting from the docs is that bar\[\[1\]\] should be 2. Instead, the key is not found, and neither is (the new) foo or bar\[\[1,3\]\]. When I print bar it se…

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## [Help me with @eval](https://discourse.julialang.org/t/help-me-with-eval/59341)

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**Author:** [@Impressium](https://discourse.julialang.org/u/Impressium)\
**Replies:** 5\
**Last updated:** [April 15, 2021, 2:04pm UTC](https://discourse.julialang.org/t/help-me-with-eval/59341 "2021-04-15T14:04:56Z")

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Hey all :slight\_smile: Below I wrote a minimal working example of what I’m trying to do. But I can’t get it to work. I’m doing something wrong. julia\> mutable struct Test field\_1 field\_2 …

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## [Interactive audio spectrograms - new user](https://discourse.julialang.org/t/interactive-audio-spectrograms-new-user/59280)

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**Author:** [@CosmicSpittle](https://discourse.julialang.org/u/CosmicSpittle)\
**Replies:** 5\
**Last updated:** [April 15, 2021, 1:55pm UTC](https://discourse.julialang.org/t/interactive-audio-spectrograms-new-user/59280 "2021-04-15T13:55:45Z")

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I am new to Julia and would like to visualize, annotate, and listen to audio clips, eventually in a Pluto notebook. Ideally, I would like to import a sound file and create a spectrogram with a play button to hear the cl…

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## [How to save Conda path change permanently?](https://discourse.julialang.org/t/how-to-save-conda-path-change-permanently/59340)

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**Author:** [@jolly](https://discourse.julialang.org/u/jolly)\
**Replies:** 0\
**Last updated:** [April 15, 2021, 1:21pm UTC](https://discourse.julialang.org/t/how-to-save-conda-path-change-permanently/59340 "2021-04-15T13:21:55Z")

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Hello, I am using some Python packages, such as numpy. I am calling it in Julia using PyCall. Two things seems suboptimal and I cannot figure out how to solve it: The Python packages are not found and do not get imp…

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## [Converting 1×10 Array{Int64,2} to 10x1 Array{Int64,2}](https://discourse.julialang.org/t/converting-1x10-array-int64-2-to-10x1-array-int64-2/59316)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 7\
**Last updated:** [April 15, 2021, 1:12pm UTC](https://discourse.julialang.org/t/converting-1x10-array-int64-2-to-10x1-array-int64-2/59316 "2021-04-15T13:12:40Z")

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A = \[0 0 0 0 0 0 0 0 0 0\] is a 1×10 Array{Int64,2}. Why is A’ not a 10x1 Array{Int64,2} but a 10×1 Adjoint{Int64,Array{Int64,2}}? Or, how do I convert A to a 10x1 Array{Int64,2}?

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## [Reading byte-aligned struct from binary file](https://discourse.julialang.org/t/reading-byte-aligned-struct-from-binary-file/59323)

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**Author:** [@GeraldJansen](https://discourse.julialang.org/u/GeraldJansen)\
**Replies:** 2\
**Last updated:** [April 15, 2021, 1:08pm UTC](https://discourse.julialang.org/t/reading-byte-aligned-struct-from-binary-file/59323 "2021-04-15T13:08:05Z")

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I need to read data from a binary file created by a C program using a byte-aligned struct. Below is a reduced version of the C program and my best effort at reading the binary file in Julia. #include \<stdio.h\> typedef …

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## [Visual workflow tool for Julia - let's build one!](https://discourse.julialang.org/t/visual-workflow-tool-for-julia-lets-build-one/9384)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 24\
**Last updated:** [April 15, 2021, 11:48am UTC](https://discourse.julialang.org/t/visual-workflow-tool-for-julia-lets-build-one/9384 "2021-04-15T11:48:47Z")

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I have always liked visual data science and machine learning tools that let you use a mixture of flowcharts and code to write data manipulation and machine learning models. There are some popular ones out there including…

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## [Julia contour lines issue](https://discourse.julialang.org/t/julia-contour-lines-issue/59333)

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**Author:** [@safhjkas](https://discourse.julialang.org/u/safhjkas)\
**Replies:** 1\
**Last updated:** [April 15, 2021, 11:33am UTC](https://discourse.julialang.org/t/julia-contour-lines-issue/59333 "2021-04-15T11:33:51Z")

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i am trying to sketch a contour lines plot by the code, but it shows “ERROR: UndefVarError: K not defined” can anyone help on how to define the K? xvec = GradientDescent(\[1;1\]) plot!(xvec\[1,1:1:K\], xvec\[2,1:1:K\], lw = …

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## [Small union type failure](https://discourse.julialang.org/t/small-union-type-failure/18640)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 15\
**Last updated:** [April 15, 2021, 10:52am UTC](https://discourse.julialang.org/t/small-union-type-failure/18640 "2021-04-15T10:52:05Z")

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I thought that missing wasn’t treated specially, and that all small type unions would be Unioned. Have I misunderstood? julia\> struct Blag end julia\> typeof(\[ifelse(randn() \< 0, 1.0, Missing()) for \_ in 1:100\]) Array{U…

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## [Problem with Qt dependency of Plots.jl](https://discourse.julialang.org/t/problem-with-qt-dependency-of-plots-jl/58765)

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**Author:** [@erans](https://discourse.julialang.org/u/erans)\
**Replies:** 2\
**Last updated:** [April 15, 2021, 10:37am UTC](https://discourse.julialang.org/t/problem-with-qt-dependency-of-plots-jl/58765 "2021-04-15T10:37:14Z")

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Hello, I’m having an issue with a package I’m developing that depends on Plots.jl. The gist is, that when I dev this package then I get a precompilation error: ERROR: LoadError: LoadError: InitError: could not load li…

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## [\[ANN\] FiniteMesh.jl: mesh I/O and connectivity](https://discourse.julialang.org/t/ann-finitemesh-jl-mesh-i-o-and-connectivity/59324)

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**Author:** [@vavrines](https://discourse.julialang.org/u/vavrines)\
**Replies:** 4\
**Last updated:** [April 15, 2021, 10:28am UTC](https://discourse.julialang.org/t/ann-finitemesh-jl-mesh-i-o-and-connectivity/59324 "2021-04-15T10:28:07Z")

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The current functionality of mesh I/O in Julia community seems to be far from mature. This package (GitHub - vavrines/FiniteMesh.jl: Mesh I/O and connectivity computation methods) provides a wrapper of the popular Pytho…

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## [Transparent group / layers for graphical union](https://discourse.julialang.org/t/transparent-group-layers-for-graphical-union/59321)

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**Author:** [@goretkin](https://discourse.julialang.org/u/goretkin)\
**Replies:** 0\
**Last updated:** [April 15, 2021, 9:06am UTC](https://discourse.julialang.org/t/transparent-group-layers-for-graphical-union/59321 "2021-04-15T09:06:09Z")

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SVG has a feature that allows grouping plot elements. This g tag can have its opacity adjusted, which is different than adjusting the opacity of the individual elements as demonstrated in this image from this answer wher…

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## [Is there already an auto-conversion macro for function signatures?](https://discourse.julialang.org/t/is-there-already-an-auto-conversion-macro-for-function-signatures/59320)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 0\
**Last updated:** [April 15, 2021, 9:05am UTC](https://discourse.julialang.org/t/is-there-already-an-auto-conversion-macro-for-function-signatures/59320 "2021-04-15T09:05:25Z")

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I’ve thought about making a macro to auto-convert a more general type-signature to a specific one. Is there already something like this? The reason is that often, a function realistically should only work for a couple o…

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## [After update, CUDA.jl not working](https://discourse.julialang.org/t/after-update-cuda-jl-not-working/59318)

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**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 0\
**Last updated:** [April 15, 2021, 8:57am UTC](https://discourse.julialang.org/t/after-update-cuda-jl-not-working/59318 "2021-04-15T08:57:58Z")

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Hi, yesterday I read the message about the new CUDA package. Today I just did an update (julia 1.6.0 on ubuntu mate 20.04) and the CUDA package did upgrade. After that julia\> using CUDA julia\> CUDA.zeros(10) ┌ Error:…

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## [MKL.jl build problems on windows](https://discourse.julialang.org/t/mkl-jl-build-problems-on-windows/58929)

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**Author:** [@Germinator](https://discourse.julialang.org/u/Germinator)\
**Replies:** 3\
**Last updated:** [April 15, 2021, 7:55am UTC](https://discourse.julialang.org/t/mkl-jl-build-problems-on-windows/58929 "2021-04-15T07:55:51Z")

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Hi all! I am trying to build MKL on Windows. Setting: ENV\["USE\_BLAS64"\] = true; \] add MKL; results in: Building MKL → \`C:\\Users\\LocalAdmin\\.julia\\scratchspaces\\44cfe95a-1eb2-52ea-b672-e2afdf69b78f\\52c39a2b15674387…

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## [Converting DateTime in DataFrames indo Data](https://discourse.julialang.org/t/converting-datetime-in-dataframes-indo-data/59210)

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**Author:** [@Kinga](https://discourse.julialang.org/u/Kinga)\
**Replies:** 9\
**Last updated:** [April 15, 2021, 6:55am UTC](https://discourse.julialang.org/t/converting-datetime-in-dataframes-indo-data/59210 "2021-04-15T06:55:49Z")

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Hi! I’m reading csv file and puttining it into DataFrames. I can’t cope with changing the time column from “2019-11-18T13:09:31Z” format to “2019-11-18”. Can someone help me ? I have code function read\_data('query.cs…

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## [Frequency Response Functions (FRF) in Julia](https://discourse.julialang.org/t/frequency-response-functions-frf-in-julia/57900)

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**Author:** [@Eggy](https://discourse.julialang.org/u/Eggy)\
**Replies:** 49\
**Last updated:** [April 15, 2021, 3:36am UTC](https://discourse.julialang.org/t/frequency-response-functions-frf-in-julia/57900 "2021-04-15T03:36:24Z")

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I have followed Julia for a while, but I am now just getting into using it more. I have collected data from performing what’s known as an roving hammer test with my accelerometer and an non-instrumented hammer to derive …

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## [New Game Project](https://discourse.julialang.org/t/new-game-project/58985)

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**Author:** [@Vos](https://discourse.julialang.org/u/Vos)\
**Replies:** 4\
**Last updated:** [April 15, 2021, 3:26am UTC](https://discourse.julialang.org/t/new-game-project/58985 "2021-04-15T03:26:11Z")

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Hello to all, We are a group of friends who are passionate about challenges and we have just set a new one. We would like to create a game with Julia using Pluto. This game is called Vector Formula (it’s a game that alr…

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## [\` add DataFrames@0.22.7\` has no effect](https://discourse.julialang.org/t/add-dataframes-0-22-7-has-no-effect/59313)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [April 15, 2021, 2:23am UTC](https://discourse.julialang.org/t/add-dataframes-0-22-7-has-no-effect/59313 "2021-04-15T02:23:41Z")

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I am using Julia 1.6 on Windows. When I try to add DataFrames@0.22.7 I just see Resolving package versions... No Changes to \`C:\\Users\\un\\.julia\\environments\\v1.6\\Project.toml\` No Changes to \`C:\\Users\\un\\.julia\\…

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## [Softmax applied to arrays?](https://discourse.julialang.org/t/softmax-applied-to-arrays/59299)

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**Author:** [@dadada\_dadada](https://discourse.julialang.org/u/dadada_dadada)\
**Replies:** 2\
**Last updated:** [April 14, 2021, 9:56pm UTC](https://discourse.julialang.org/t/softmax-applied-to-arrays/59299 "2021-04-14T21:56:01Z")

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Hi everybody, I would like to repeatedly apply (a variation of) the softmax function to parts of an array. I would like to know if there are ways to leverage packages like Tullio, Yeppp, and other Julianic features as …

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## [Struct with new instances according to arguments passed](https://discourse.julialang.org/t/struct-with-new-instances-according-to-arguments-passed/59292)

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**Author:** [@deveshjawla](https://discourse.julialang.org/u/deveshjawla)\
**Replies:** 5\
**Last updated:** [April 14, 2021, 9:46pm UTC](https://discourse.julialang.org/t/struct-with-new-instances-according-to-arguments-passed/59292 "2021-04-14T21:46:31Z")

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Hello, I would like to know if there exists any concise solution to create a struct which can be initialised with any number of arguments? like so: struct VariableStruct a b c d e f return new(;a,b,c,d,e,f) end With …

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## [Updating expressions for indicator constraints in JuMP](https://discourse.julialang.org/t/updating-expressions-for-indicator-constraints-in-jump/59059)

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**Author:** [@Maria95](https://discourse.julialang.org/u/Maria95)\
**Replies:** 7\
**Last updated:** [April 14, 2021, 9:28pm UTC](https://discourse.julialang.org/t/updating-expressions-for-indicator-constraints-in-jump/59059 "2021-04-14T21:28:20Z")

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Hello, I am trying to implement a constraint with a conditional statement that I am making piecewise affine by introducing binary variables and using the big M method. I know that JuMP supports indicator constraints but …

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## [Packages for game theory](https://discourse.julialang.org/t/packages-for-game-theory/59255)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 2\
**Last updated:** [April 14, 2021, 9:22pm UTC](https://discourse.julialang.org/t/packages-for-game-theory/59255 "2021-04-14T21:22:16Z")

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What packages are there for game theory?

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## [How to show the row numbers inside the Julia Table in VSCode?](https://discourse.julialang.org/t/how-to-show-the-row-numbers-inside-the-julia-table-in-vscode/59249)

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**Author:** [@AA\_julia](https://discourse.julialang.org/u/AA_julia)\
**Replies:** 2\
**Last updated:** [April 14, 2021, 9:20pm UTC](https://discourse.julialang.org/t/how-to-show-the-row-numbers-inside-the-julia-table-in-vscode/59249 "2021-04-14T21:20:48Z")

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How can I show the rows indices inside the Julia Table in VSCode? I can only see the columns indices, as shown below. For now, I’m using this trick: x = \[1:length(x) x\], but I’m wondering if there is a better/default met…

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## [sciML\_train func running but not optimizing](https://discourse.julialang.org/t/sciml-train-func-running-but-not-optimizing/59251)

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**Author:** [@willsharpless](https://discourse.julialang.org/u/willsharpless)\
**Replies:** 5\
**Last updated:** [April 14, 2021, 8:04pm UTC](https://discourse.julialang.org/t/sciml-train-func-running-but-not-optimizing/59251 "2021-04-14T20:04:37Z")

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Hi all, My executions of DiffEqFlux.sciml\_train are not optimizing but yet are iterating for the full amount without error. By not optimizing, I mean that for whatever random initial parameters I feed for a fitting exam…

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## [What does GKSwstype do?](https://discourse.julialang.org/t/what-does-gkswstype-do/59226)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 3\
**Last updated:** [April 14, 2021, 7:53pm UTC](https://discourse.julialang.org/t/what-does-gkswstype-do/59226 "2021-04-14T19:53:58Z")

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I can see GKSwstype being used in a lot of workarounds for Plots/GR. Is there documentation on what the different options do? I just found a list of options in the C code of GR and I think it sets the (interactive) ren…

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