# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1932

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

**Page:** 1933

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## [How to optimize simple matrix equation solving](https://discourse.julialang.org/t/how-to-optimize-simple-matrix-equation-solving/23035)

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**Author:** [@Johncowk](https://discourse.julialang.org/u/Johncowk)\
**Replies:** 16\
**Last updated:** [August 28, 2019, 1:00pm UTC](https://discourse.julialang.org/t/how-to-optimize-simple-matrix-equation-solving/23035 "2019-08-28T13:00:40Z")

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Hello ! I implemented a method which aims at detecting change-point in categorical time-serie, which gives correct results but is way too slow (slower than the python version already available, which is itself already s…

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## [Get all combinations](https://discourse.julialang.org/t/get-all-combinations/27461)

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**Author:** [@1112](https://discourse.julialang.org/u/1112)\
**Replies:** 6\
**Last updated:** [August 28, 2019, 12:55pm UTC](https://discourse.julialang.org/t/get-all-combinations/27461 "2019-08-28T12:55:31Z")

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Hello, tell me what are the methods for enumerating all the combination of characters. I have such a line. “ABC1abc” I want to get this as a result Abc ABC CBA C1A BC1 …

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## [Installed Julia Pro reverts to "generic" Atom](https://discourse.julialang.org/t/installed-julia-pro-reverts-to-generic-atom/8936)

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**Author:** [@fjhickernell](https://discourse.julialang.org/u/fjhickernell)\
**Replies:** 14\
**Last updated:** [August 28, 2019, 12:34pm UTC](https://discourse.julialang.org/t/installed-julia-pro-reverts-to-generic-atom/8936 "2019-08-28T12:34:02Z")

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After downloading and installing Julia Pro on my Mac, I open it, change the themes, edit my Julia function, and quit. When I re-open Julia Pro, it has turned into some generic Atom with no Julia menu. Re-installing Jul…

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## [\[Possible Bug?\] Weird behavior with small negative indices in findnext()](https://discourse.julialang.org/t/possible-bug-weird-behavior-with-small-negative-indices-in-findnext/28057)

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**Author:** [@AndrewQuinn2020](https://discourse.julialang.org/u/AndrewQuinn2020)\
**Replies:** 3\
**Last updated:** [August 28, 2019, 12:02pm UTC](https://discourse.julialang.org/t/possible-bug-weird-behavior-with-small-negative-indices-in-findnext/28057 "2019-08-28T12:02:03Z")

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Take a look at this, y’all, and tell me if this is a bug – I’ll step up later this week to fix it and write some @tests for it if so. julia\> versioninfo() Julia Version 1.2.0 Commit c6da87ff4b (2019-08-20 00:03 UTC) Pla…

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## [SingularException(2) error while doing complex matrix inversion](https://discourse.julialang.org/t/singularexception-2-error-while-doing-complex-matrix-inversion/28095)

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**Author:** [@mamuniut09](https://discourse.julialang.org/u/mamuniut09)\
**Replies:** 2\
**Last updated:** [August 28, 2019, 11:13am UTC](https://discourse.julialang.org/t/singularexception-2-error-while-doing-complex-matrix-inversion/28095 "2019-08-28T11:13:25Z")

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I wanted to have the inverse of a complex matrix, but it shows SingularException (2) error. For example: a=\[1.0+2.0im 1.0+2.0im; 3.0+4.0im 3.0+4.0im\]; inv(a) It gives the error SingularException(2) I was wondering i…

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## [Concrete types for Dicts in container](https://discourse.julialang.org/t/concrete-types-for-dicts-in-container/28043)

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**Author:** [@mrVeng](https://discourse.julialang.org/u/mrVeng)\
**Replies:** 3\
**Last updated:** [August 28, 2019, 9:46am UTC](https://discourse.julialang.org/t/concrete-types-for-dicts-in-container/28043 "2019-08-28T09:46:42Z")

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Hi everyone! I am trying to construct a container that holds vectors of different probabilities (but they are all either multi- or univariate). This container is used to store prior distributions of parameter I use in a…

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## [Reducing Allocation](https://discourse.julialang.org/t/reducing-allocation/28078)

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**Author:** [@Ajaychat3](https://discourse.julialang.org/u/Ajaychat3)\
**Replies:** 4\
**Last updated:** [August 28, 2019, 8:40am UTC](https://discourse.julialang.org/t/reducing-allocation/28078 "2019-08-28T08:40:14Z")

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Out of curiosity, is it possible to make the function zero allocation? The output excludes compile time. using StatsPlots,Random, BenchmarkTools # using TimerOutputs Random.seed!(123) function createPath(S, r, sigma, T,…

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## [How to easily create graphs from tables?](https://discourse.julialang.org/t/how-to-easily-create-graphs-from-tables/28069)

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**Author:** [@Juan](https://discourse.julialang.org/u/Juan)\
**Replies:** 2\
**Last updated:** [August 28, 2019, 8:38am UTC](https://discourse.julialang.org/t/how-to-easily-create-graphs-from-tables/28069 "2019-08-28T08:38:18Z")

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Imagine I have a table with nested levels or a csv file with information like this: (or a little bit more complex with numbers on the right side) fig date kumquat papaya peach …

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## [Surface AST to surface AST lowering/desugaring?](https://discourse.julialang.org/t/surface-ast-to-surface-ast-lowering-desugaring/28067)

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**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 7\
**Last updated:** [August 28, 2019, 8:35am UTC](https://discourse.julialang.org/t/surface-ast-to-surface-ast-lowering-desugaring/28067 "2019-08-28T08:35:55Z")

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Is there any function/package to do surface AST to surface AST lowering? I’m aware of Meta.lower but it does not produce a surface AST that can be used as an output of a macro. The only relevant thing I know is @c42f’s…

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## [Shell escaping](https://discourse.julialang.org/t/shell-escaping/28087)

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**Author:** [@phlavenk](https://discourse.julialang.org/u/phlavenk)\
**Replies:** 1\
**Last updated:** [August 28, 2019, 8:35am UTC](https://discourse.julialang.org/t/shell-escaping/28087 "2019-08-28T08:35:13Z")

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How to run a command with \* without getting warning about command misuse? run(\`attrib -r $projectworkdir\\\\\*.\* /s\`) #clearing readonly attribs ┌ Warning: special characters "#{}()\[\]\<\>|&\*?~;" should now be quoted in comma…

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## [Choosing not to plot](https://discourse.julialang.org/t/choosing-not-to-plot/28085)

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**Author:** [@notstpaul](https://discourse.julialang.org/u/notstpaul)\
**Replies:** 4\
**Last updated:** [August 28, 2019, 8:28am UTC](https://discourse.julialang.org/t/choosing-not-to-plot/28085 "2019-08-28T08:28:54Z")

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Greetings everyone, I don’t want to plot my functions every time I run the script and I don’t want Plots to load when I’m not plotting, but I found that I can’t place the using Plots statement inside an if/else statem…

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## [\[ANN\] LambdaFn.jl](https://discourse.julialang.org/t/ann-lambdafn-jl/28054)

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**Author:** [@haberdashPI](https://discourse.julialang.org/u/haberdashPI)\
**Replies:** 2\
**Last updated:** [August 28, 2019, 6:06am UTC](https://discourse.julialang.org/t/ann-lambdafn-jl/28054 "2019-08-28T06:06:04Z")

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Hi all, I have created the following, very small, package: LambdaFn.jl. It’s for creating anonymous functions in a way I find to be handy. It’s best explained by example: using LambdaFn @λ(\_ + \_) # == (x,y) -\> x+y @λ…

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## [Spiraling outwards iterator](https://discourse.julialang.org/t/spiraling-outwards-iterator/27938)

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**Author:** [@rapus95](https://discourse.julialang.org/u/rapus95)\
**Replies:** 3\
**Last updated:** [August 28, 2019, 2:50am UTC](https://discourse.julialang.org/t/spiraling-outwards-iterator/27938 "2019-08-28T02:50:08Z")

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Hey, I was looking for an iterator that spirals outward a given point. By that I stumbled over a Rosetta Code Challenge seeing that it is outdated (old iterator protocol) and that it goes inward clockwise. Thus it didn’…

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## [Julia / Python 2 / Python 3 interoperability](https://discourse.julialang.org/t/julia-python-2-python-3-interoperability/27541)

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**Author:** [@marius311](https://discourse.julialang.org/u/marius311)\
**Replies:** 9\
**Last updated:** [August 28, 2019, 1:11am UTC](https://discourse.julialang.org/t/julia-python-2-python-3-interoperability/27541 "2019-08-28T01:11:51Z")

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I’m in the scenario that I need to call Python 2 legacy code from Julia, but I also do all my plotting from PyPlot/matplotlib and hence want to use a modern Python 3 matplotlib, and I want to do this all from a single Ju…

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## [Package update issue](https://discourse.julialang.org/t/package-update-issue/28028)

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**Author:** [@Ajaychat3](https://discourse.julialang.org/u/Ajaychat3)\
**Replies:** 1\
**Last updated:** [August 28, 2019, 1:25am UTC](https://discourse.julialang.org/t/package-update-issue/28028 "2019-08-28T01:25:22Z")

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Today I tried to update julia packages and got the following output. It first threw an error for Clp. I removed Clp then CPLEX got downgraded to 0.3.3 along side an error message “Is\_apple not defined”. I tried to upgrad…

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## [How to declare a type](https://discourse.julialang.org/t/how-to-declare-a-type/28068)

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**Author:** [@Santiago\_Cuervo](https://discourse.julialang.org/u/Santiago_Cuervo)\
**Replies:** 4\
**Last updated:** [August 28, 2019, 1:17am UTC](https://discourse.julialang.org/t/how-to-declare-a-type/28068 "2019-08-28T01:17:42Z")

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I want to declare a type that describe a Well. mutable struct Well Name::String Surv::Survey Perf::Array{Perf} end I want to define if the well is either Injector or producer. How could I define it? Inject…

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## [Help with julia script](https://discourse.julialang.org/t/help-with-julia-script/28052)

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**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 4\
**Last updated:** [August 28, 2019, 12:57am UTC](https://discourse.julialang.org/t/help-with-julia-script/28052 "2019-08-28T00:57:24Z")

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Hello, I’m having a strange issue on one of my julia scripts. It clearly completes to the end, but doesn’t exit the script. The last two lines of the script are the following. println("all complete") exit() I can se…

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## [Knet.jl: Simple MLP for Iris Dataset](https://discourse.julialang.org/t/knet-jl-simple-mlp-for-iris-dataset/24839)

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**Author:** [@alasaadstat](https://discourse.julialang.org/u/alasaadstat)\
**Replies:** 6\
**Last updated:** [August 28, 2019, 12:26am UTC](https://discourse.julialang.org/t/knet-jl-simple-mlp-for-iris-dataset/24839 "2019-08-28T00:26:11Z")

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Hi everyone, I’m currently studying (I’m not done reading the docs yet) how Knet works. I’m trying to create a classification model for the iris dataset. That is, using the four features of the iris dataset as the predic…

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## [Where do you put your "main" function in your projects?](https://discourse.julialang.org/t/where-do-you-put-your-main-function-in-your-projects/28026)

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**Author:** [@tviti](https://discourse.julialang.org/u/tviti)\
**Replies:** 5\
**Last updated:** [August 27, 2019, 9:21pm UTC](https://discourse.julialang.org/t/where-do-you-put-your-main-function-in-your-projects/28026 "2019-08-27T21:21:46Z")

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I’ve been working on a side project to convert an old fortran program to Julia (mostly as an escape from working on my thesis, and an excuse to learn Julia) and recently have started experimenting with encapsulating the …

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## [Unexported functions](https://discourse.julialang.org/t/unexported-functions/28061)

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**Author:** [@mrkaspa](https://discourse.julialang.org/u/mrkaspa)\
**Replies:** 6\
**Last updated:** [August 27, 2019, 8:51pm UTC](https://discourse.julialang.org/t/unexported-functions/28061 "2019-08-27T20:51:46Z")

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Why if I have a module like this: module Demo suma(a) = a + 1 end I can access it through Demo.suma(123), if it has not been exported, should not be exported first to be accessed?

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## [JuliaDB saving arrays](https://discourse.julialang.org/t/juliadb-saving-arrays/28059)

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**Author:** [@grahamas](https://discourse.julialang.org/u/grahamas)\
**Replies:** 1\
**Last updated:** [August 27, 2019, 7:35pm UTC](https://discourse.julialang.org/t/juliadb-saving-arrays/28059 "2019-08-27T19:35:37Z")

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I’m running a parameter sweep solving differential equations and trying to save the results, and have a couple questions: When I try to save a toy example as follows, I get an error that \_impl is not defined for my arg…

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## [Length from iterator?](https://discourse.julialang.org/t/length-from-iterator/27821)

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**Author:** [@gabomgp](https://discourse.julialang.org/u/gabomgp)\
**Replies:** 22\
**Last updated:** [August 27, 2019, 7:40pm UTC](https://discourse.julialang.org/t/length-from-iterator/27821 "2019-08-27T19:40:42Z")

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I’m searching for a way to get the lenght from a iterator. The iterator can be consumed, is not problem. So, I’m find Query.jl, IterTools.jl and the iterator methods from base, but i’m not finding something to calculate …

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## [Calling \`similar()\` with all the three input arguments](https://discourse.julialang.org/t/calling-similar-with-all-the-three-input-arguments/28047)

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**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 3\
**Last updated:** [August 27, 2019, 7:06pm UTC](https://discourse.julialang.org/t/calling-similar-with-all-the-three-input-arguments/28047 "2019-08-27T19:06:05Z")

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I am trying to understand the full usage of similar(). The manual shows an example similar(falses(10), Float64, 2, 4) and states that Since BitArray s can only store elements of type Bool , however, if you request a…

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## [JuliaDiffEq Vern9() solver taking too long](https://discourse.julialang.org/t/juliadiffeq-vern9-solver-taking-too-long/27970)

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**Author:** [@Prince\_Mahajan](https://discourse.julialang.org/u/Prince_Mahajan)\
**Replies:** 18\
**Last updated:** [August 27, 2019, 6:57pm UTC](https://discourse.julialang.org/t/juliadiffeq-vern9-solver-taking-too-long/27970 "2019-08-27T18:57:02Z")

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I wrote a simple julia script to benchmark Verner9 solver from JuliaDiffEq against my fortran code and I am seeing the former is taking too long compared to the latter. Since I am very new to Julia, i thought someone her…

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## [ERROR: Package CuArrays errored during testing](https://discourse.julialang.org/t/error-package-cuarrays-errored-during-testing/28006)

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**Author:** [@sergevic](https://discourse.julialang.org/u/sergevic)\
**Replies:** 2\
**Last updated:** [August 27, 2019, 4:31pm UTC](https://discourse.julialang.org/t/error-package-cuarrays-errored-during-testing/28006 "2019-08-27T16:31:59Z")

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I followed all the steps in https://juliagpu.gitlab.io/CuArrays.jl/tutorials/generated/intro/ to install Cuda for using it in Julia v. 1.1. I also installed the CUDA Toolkit v. 10.1. After the installation, I run test Cu…

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## [Remove box around plot](https://discourse.julialang.org/t/remove-box-around-plot/4039)

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**Author:** [@Holy\_Monk](https://discourse.julialang.org/u/Holy_Monk)\
**Replies:** 1\
**Last updated:** [August 27, 2019, 2:18pm UTC](https://discourse.julialang.org/t/remove-box-around-plot/4039 "2019-08-27T14:18:00Z")

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I’m making a plot where I plot some y data (say yy) to some x data (say xx). I would like to remove everything surrounding my plot (labels, ticks etc.) and save the output as an svg file. For this I use: draw(SVG(“Benfo…

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## [Codegen woes](https://discourse.julialang.org/t/codegen-woes/27098)

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**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 30\
**Last updated:** [August 27, 2019, 2:16pm UTC](https://discourse.julialang.org/t/codegen-woes/27098 "2019-08-27T14:16:16Z")

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Hello all, There’s an expressiveness problem I’ve been fighting with for quite a while now. I had thought (and hoped, really) I might just be missing something obvious. But from discussions at JuliaCon, it seems at leas…

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## [3D Conv Training Error](https://discourse.julialang.org/t/3d-conv-training-error/26831)

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**Author:** [@MaximilianGelbrecht](https://discourse.julialang.org/u/MaximilianGelbrecht)\
**Replies:** 1\
**Last updated:** [August 27, 2019, 1:25pm UTC](https://discourse.julialang.org/t/3d-conv-training-error/26831 "2019-08-27T13:25:45Z")

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Hi there, I encountered an error while setting up a 3D CNN that I dont understand. The problems boils down to this: While in 2D using Flux a, b = rand(5,10,2,10), rand(5,10,2,10) m= Chain(Conv((3,3),2=\>4,pad=(1,1)), …

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## [Remove temporal files of previous installations](https://discourse.julialang.org/t/remove-temporal-files-of-previous-installations/28031)

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**Author:** [@carlomontec](https://discourse.julialang.org/u/carlomontec)\
**Replies:** 2\
**Last updated:** [August 27, 2019, 9:06am UTC](https://discourse.julialang.org/t/remove-temporal-files-of-previous-installations/28031 "2019-08-27T09:06:48Z")

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Hi, I just checked out version 1.2 from GitHub and compiled it, and saw my installation folder is more than 5Gb. I saw that in the folder /deps/scratch there are some folders of libraries of different versions, which lo…

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## [DataFrame or DataFrameRow to Dict and JSON](https://discourse.julialang.org/t/dataframe-or-dataframerow-to-dict-and-json/28018)

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**Author:** [@milesf](https://discourse.julialang.org/u/milesf)\
**Replies:** 1\
**Last updated:** [August 27, 2019, 6:00am UTC](https://discourse.julialang.org/t/dataframe-or-dataframerow-to-dict-and-json/28018 "2019-08-27T06:00:21Z")

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Wanted to double-check if there are any recommended ways to convert a DataFrame (or DataFrameRow) into a Dict (for eventually conversion to JSON). This is the inverse of this question. “List of Dicts” JSON format would …

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