# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1928

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

**Page:** 1929

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## [Subplots without gap between them](https://discourse.julialang.org/t/subplots-without-gap-between-them/27491)

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**Author:** [@Topias\_Karjalainen](https://discourse.julialang.org/u/Topias_Karjalainen)\
**Replies:** 3\
**Last updated:** [September 3, 2019, 10:06am UTC](https://discourse.julialang.org/t/subplots-without-gap-between-them/27491 "2019-09-03T10:06:33Z")

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Hi! I’m trying to create a plotting package for plotting financial data (as an exercise, and as a tool that I need). For it to look like I want it to look, I need to plot a subplot for indicators under the main plot tha…

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## [Reshape Singleton Array to Scalar](https://discourse.julialang.org/t/reshape-singleton-array-to-scalar/28285)

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**Author:** [@mrVeng](https://discourse.julialang.org/u/mrVeng)\
**Replies:** 4\
**Last updated:** [September 3, 2019, 9:27am UTC](https://discourse.julialang.org/t/reshape-singleton-array-to-scalar/28285 "2019-09-03T09:27:49Z")

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Hey everyone, I have a vector of vectors, x, and a vector of scalars, x\_proposed. Both have the same number of elements: x = \[ \[.3, .4, .3 \], \[.5, .4, .1\], 1., 2., \[3., 4.\] \] x\_proposed = \[ 5, 6, 7, 8, 9, 10, 11, 12, …

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## [ANN: UnitfulRecipes.jl](https://discourse.julialang.org/t/ann-unitfulrecipes-jl/28280)

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**Author:** [@jw3126](https://discourse.julialang.org/u/jw3126)\
**Replies:** 11\
**Last updated:** [September 3, 2019, 7:22am UTC](https://discourse.julialang.org/t/ann-unitfulrecipes-jl/28280 "2019-09-03T07:22:26Z")

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UnitfulRecipes.jl is a tiny package, that makes plotting Unitful quantities more convenient: using Unitful: cm, kg using UnitfulRecipes using Plots xs = 1cm:1cm:10cm ys = randn(10)\*kg plot(xs, ys) It was inspired by…

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## [Error, parallel computing in a module](https://discourse.julialang.org/t/error-parallel-computing-in-a-module/28275)

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**Author:** [@zhangliye](https://discourse.julialang.org/u/zhangliye)\
**Replies:** 2\
**Last updated:** [September 3, 2019, 3:06am UTC](https://discourse.julialang.org/t/error-parallel-computing-in-a-module/28275 "2019-09-03T03:06:00Z")

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I am creating a package which use parallel computing. I encountered some errors and not sure which place to put addprocs() and implement the parallel code. Please give some suggestions. The code is as follows. Repost: …

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## [Using a (normalized) Histogram as a Distribution](https://discourse.julialang.org/t/using-a-normalized-histogram-as-a-distribution/27682)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 29\
**Last updated:** [September 3, 2019, 1:28am UTC](https://discourse.julialang.org/t/using-a-normalized-histogram-as-a-distribution/27682 "2019-09-03T01:28:44Z")

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Do we have a wrapper somewhere that turns a StatsBase.Histogram into a Distributions.Distribution?

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## [Another intro to DataFrames.jl](https://discourse.julialang.org/t/another-intro-to-dataframes-jl/28308)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 0\
**Last updated:** [September 3, 2019, 12:36am UTC](https://discourse.julialang.org/t/another-intro-to-dataframes-jl/28308 "2019-09-03T00:36:16Z")

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This seems to be a fairly competent intro to DataFrames.jl https://github.com/sylvaticus/juliatutorial Didn’t seem to get much attention. Of course there is also https://github.com/bkamins/Julia-DataFrames-Tutorial whic…

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## [ERROR: InvalidIRError: compiling reduce\_kernel with \`eigen\` command](https://discourse.julialang.org/t/error-invalidirerror-compiling-reduce-kernel-with-eigen-command/28307)

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**Author:** [@sergevic](https://discourse.julialang.org/u/sergevic)\
**Replies:** 4\
**Last updated:** [September 3, 2019, 12:31am UTC](https://discourse.julialang.org/t/error-invalidirerror-compiling-reduce-kernel-with-eigen-command/28307 "2019-09-03T00:31:34Z")

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I’m trying to convert my Julia code with CUDA programming, because I get a OutOfMemory() error when I run the original code on Julia v.1.2. My converted code starts with the following lines: using CuArrays using Dista…

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## [Group-by performance benchmarks and recommendations](https://discourse.julialang.org/t/group-by-performance-benchmarks-and-recommendations/9313)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 12\
**Last updated:** [September 2, 2019, 9:58pm UTC](https://discourse.julialang.org/t/group-by-performance-benchmarks-and-recommendations/9313 "2019-09-02T21:58:48Z")

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I have been trying to improve Julia’s DataFrame group-by for a while now and I think I am able to synthesized my thinking into APIs. Here are my synthesized recommendation (as of 25th Feb 2018) Recommendation Why? B…

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## [What happens in struct construction](https://discourse.julialang.org/t/what-happens-in-struct-construction/28305)

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**Author:** [@jasonsun0310](https://discourse.julialang.org/u/jasonsun0310)\
**Replies:** 5\
**Last updated:** [September 2, 2019, 10:11pm UTC](https://discourse.julialang.org/t/what-happens-in-struct-construction/28305 "2019-09-02T22:11:23Z")

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I wonder what is under the hood in the construction process of a struct. For example: struct A field::Dict member\_function function A(::Type{Int64}) return new(Dict(1 =\> "one"), nothing) end …

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## [Read and write/save 3-D image](https://discourse.julialang.org/t/read-and-write-save-3-d-image/26978)

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**Author:** [@Yoshua](https://discourse.julialang.org/u/Yoshua)\
**Replies:** 5\
**Last updated:** [September 2, 2019, 9:50pm UTC](https://discourse.julialang.org/t/read-and-write-save-3-d-image/26978 "2019-09-02T21:50:33Z")

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Hello! I have problem with image manipulation. I want to save a 3D image array in png format. Also wanted to know how to plot an image with some function of ImageView or Image package. Image encoding is RGB. If anyon…

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## [Keeping (AOT-compiling) runtime-generated functions](https://discourse.julialang.org/t/keeping-aot-compiling-runtime-generated-functions/27974)

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**Author:** [@asprionj](https://discourse.julialang.org/u/asprionj)\
**Replies:** 4\
**Last updated:** [September 2, 2019, 9:37pm UTC](https://discourse.julialang.org/t/keeping-aot-compiling-runtime-generated-functions/27974 "2019-09-02T21:37:46Z")

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I’m using code generation to generate efficient implementations of nested functions. That is, some functions are generated first and then used in another code-generated function. In a REPL-based workflow, this works fine…

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## [DSL help with nested macros](https://discourse.julialang.org/t/dsl-help-with-nested-macros/28267)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 5\
**Last updated:** [September 2, 2019, 7:26pm UTC](https://discourse.julialang.org/t/dsl-help-with-nested-macros/28267 "2019-09-02T19:26:26Z")

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Hi all. I’m learning how to implement DSL using macros and some help would be appreciated. In particular, I would like to create a DSL for L-System. The purpose of DSL is clean syntax. So here’s what I’m thinking in …

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## [Chained comparisons on arrays allocating](https://discourse.julialang.org/t/chained-comparisons-on-arrays-allocating/28301)

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**Author:** [@3d5g](https://discourse.julialang.org/u/3d5g)\
**Replies:** 2\
**Last updated:** [September 2, 2019, 7:21pm UTC](https://discourse.julialang.org/t/chained-comparisons-on-arrays-allocating/28301 "2019-09-02T19:21:04Z")

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I consistently get heap allocations in groups of 3 of 4.33 KiB for each chain of comparisons: x = randn(Float64, (2,3)) y = similar(x) z @btime @. $y = -1 \<= $x \< 1 This prints “481.026 ns (3 allocations: 4.33 KiB)”. …

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## [Is there a way to do unsafe type coercions?](https://discourse.julialang.org/t/is-there-a-way-to-do-unsafe-type-coercions/28281)

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**Author:** [@thautwarm](https://discourse.julialang.org/u/thautwarm)\
**Replies:** 14\
**Last updated:** [September 2, 2019, 7:00pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-do-unsafe-type-coercions/28281 "2019-09-02T19:00:46Z")

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Let the compiler treat an object as a custom specified type. It’s unsafe but it’s necessary for this:

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## [How to use Flux.train! to train custom layer?](https://discourse.julialang.org/t/how-to-use-flux-train-to-train-custom-layer/28293)

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**Author:** [@zhangqian](https://discourse.julialang.org/u/zhangqian)\
**Replies:** 2\
**Last updated:** [September 2, 2019, 6:45pm UTC](https://discourse.julialang.org/t/how-to-use-flux-train-to-train-custom-layer/28293 "2019-09-02T18:45:13Z")

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Hi I am trying to build a toy custom layer according to the instruction from Building Layers (Basics · Flux) in Basics · Flux, and train it with the train! method in Flux.jl. However, the loss does not decrease and the …

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## [The following package names could not be resolved](https://discourse.julialang.org/t/the-following-package-names-could-not-be-resolved/14258)

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**Author:** [@bdeonovic](https://discourse.julialang.org/u/bdeonovic)\
**Replies:** 4\
**Last updated:** [September 2, 2019, 6:34pm UTC](https://discourse.julialang.org/t/the-following-package-names-could-not-be-resolved/14258 "2019-09-02T18:34:37Z")

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I have no idea how to use the new Pkg system (correctly) so I am just going to describe the things I did and the things I want to have happened and maybe you guys can lead me down the right path: On a fresh install of j…

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## [Type inference and abstract interpretation](https://discourse.julialang.org/t/type-inference-and-abstract-interpretation/28259)

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**Author:** [@aml](https://discourse.julialang.org/u/aml)\
**Replies:** 3\
**Last updated:** [September 2, 2019, 5:59pm UTC](https://discourse.julialang.org/t/type-inference-and-abstract-interpretation/28259 "2019-09-02T17:59:03Z")

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Hi, For pedagogical purposes, I wrote a Scheme interpreter in Julia, which I then updated to become a toy Julia interpreter written in Julia. So far, everything OK, without any relevant performance problems, despite bei…

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## [Function declaration order?](https://discourse.julialang.org/t/function-declaration-order/28298)

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**Author:** [@jasonsun0310](https://discourse.julialang.org/u/jasonsun0310)\
**Replies:** 8\
**Last updated:** [September 2, 2019, 5:55pm UTC](https://discourse.julialang.org/t/function-declaration-order/28298 "2019-09-02T17:55:13Z")

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I am a bit confused about the function declaration order. For example, if I write following module: module A function callzeros() zeros(rand(5,5)) end function callzeros2() myzeros() end callzeros2() function …

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## [SymPy does not precompile in v1.2?](https://discourse.julialang.org/t/sympy-does-not-precompile-in-v1-2/28257)

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**Author:** [@drmartinrohde](https://discourse.julialang.org/u/drmartinrohde)\
**Replies:** 2\
**Last updated:** [September 2, 2019, 2:56pm UTC](https://discourse.julialang.org/t/sympy-does-not-precompile-in-v1-2/28257 "2019-09-02T14:56:27Z")

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I am trying to use SymPy to do some symbolic manipulation in Julia. A simple code like using SymPy @vars x f(x) = e^x results in an error when precompiling: \[ Info: Precompiling SymPy \[24249f21-da20-56a4-8eb1-6a02cf…

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## [Map function with two arguments where one isn't array](https://discourse.julialang.org/t/map-function-with-two-arguments-where-one-isnt-array/28284)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 2\
**Last updated:** [September 2, 2019, 1:52pm UTC](https://discourse.julialang.org/t/map-function-with-two-arguments-where-one-isnt-array/28284 "2019-09-02T13:52:02Z")

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Is there some way to implement map function with two arguments where one isn’t an array, without creating a new array, since it can be too large. Here is a very simple example of an idea. map(+,\[2,3\],1)

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## [Why does string(enum member value) not prepend the module name?](https://discourse.julialang.org/t/why-does-string-enum-member-value-not-prepend-the-module-name/15820)

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**Author:** [@jbrea](https://discourse.julialang.org/u/jbrea)\
**Replies:** 1\
**Last updated:** [September 2, 2019, 12:29pm UTC](https://discourse.julialang.org/t/why-does-string-enum-member-value-not-prepend-the-module-name/15820 "2019-09-02T12:29:38Z")

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julia\> module Mod struct Struct end @enum Enum A B …

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## [Animation fails in frame()](https://discourse.julialang.org/t/animation-fails-in-frame/28022)

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**Author:** [@Brad\_Hines](https://discourse.julialang.org/u/Brad_Hines)\
**Replies:** 9\
**Last updated:** [September 2, 2019, 7:35am UTC](https://discourse.julialang.org/t/animation-fails-in-frame/28022 "2019-09-02T07:35:48Z")

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I am trying to build an animation from a double-loop that goes through every hour then every minute of a day, constructing a simulated image. When my code gets to this line: Plots.frame(anim,plt) it dies with the erro…

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## [Julia v1.3.0-rc1 is now available](https://discourse.julialang.org/t/julia-v1-3-0-rc1-is-now-available/27673)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 11\
**Last updated:** [September 2, 2019, 7:14am UTC](https://discourse.julialang.org/t/julia-v1-3-0-rc1-is-now-available/27673 "2019-09-02T07:14:57Z")

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The first release candidate for Julia v1.3.0 is here! Get binaries for Linux, macOS, Windows, and FreeBSD at Download Julia and check out the NEWS file for v1.3.0-rc1 to see what will be new in 1.3. You can also view the…

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## [What IDE allow to work on 2 monitors](https://discourse.julialang.org/t/what-ide-allow-to-work-on-2-monitors/28132)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 16\
**Last updated:** [September 2, 2019, 6:33am UTC](https://discourse.julialang.org/t/what-ide-allow-to-work-on-2-monitors/28132 "2019-09-02T06:33:47Z")

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Good day. I use Atom. I like it. But unfortunately, it isn’t allowed to use two monitors for one project. Would somebody suggest how to work on two monitors? Thank you in advance.

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## [Error: Unsatisfiable requirements detected for package LinQuadOptInterface \[f8899e07\] help](https://discourse.julialang.org/t/error-unsatisfiable-requirements-detected-for-package-linquadoptinterface-f8899e07-help/28241)

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**Author:** [@N\_Mal](https://discourse.julialang.org/u/N_Mal)\
**Replies:** 3\
**Last updated:** [September 2, 2019, 2:33am UTC](https://discourse.julialang.org/t/error-unsatisfiable-requirements-detected-for-package-linquadoptinterface-f8899e07-help/28241 "2019-09-02T02:33:58Z")

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Hi, I’m new to Julia and I need some help. I’m using Julia to solve this problem (not the full problem, the forum doesn’t let me because it exceed the number of users?): import Pkg Pkg.add("JuMP") Pkg.add("CSV") Pkg.ad…

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## [How array with many NaN values convert to DataFrames with Zero instead of NaN](https://discourse.julialang.org/t/how-array-with-many-nan-values-convert-to-dataframes-with-zero-instead-of-nan/28253)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 2\
**Last updated:** [September 2, 2019, 1:07am UTC](https://discourse.julialang.org/t/how-array-with-many-nan-values-convert-to-dataframes-with-zero-instead-of-nan/28253 "2019-09-02T01:07:18Z")

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How array with many NaN values convert to DataFrames with Zero instead of NaN (without Loop) thank you in advance.

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## [Boolean subtype confusion](https://discourse.julialang.org/t/boolean-subtype-confusion/21705)

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**Author:** [@joedoewoe2](https://discourse.julialang.org/u/joedoewoe2)\
**Replies:** 16\
**Last updated:** [September 1, 2019, 10:45pm UTC](https://discourse.julialang.org/t/boolean-subtype-confusion/21705 "2019-09-01T22:45:30Z")

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Forgive if this topic is covered extensively in a multitude of different locations, but perhaps this will get everyone thinking fundamental language implementation: why is a Boolean a subset of Integer with 8 bits. Cle…

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## [Element-wise product of vector of vectors](https://discourse.julialang.org/t/element-wise-product-of-vector-of-vectors/28250)

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**Author:** [@baptiste](https://discourse.julialang.org/u/baptiste)\
**Replies:** 12\
**Last updated:** [September 1, 2019, 9:42pm UTC](https://discourse.julialang.org/t/element-wise-product-of-vector-of-vectors/28250 "2019-09-01T21:42:32Z")

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I’m moving away from a 3xN matrix representing 3D positions in favour of vectors of static vectors, as suggested in this question, but now I’m a bit stuck with this elementwise product operation for each vector, using L…

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## [First part benchmarking medium-data tools](https://discourse.julialang.org/t/first-part-benchmarking-medium-data-tools/28260)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 4\
**Last updated:** [September 1, 2019, 9:41pm UTC](https://discourse.julialang.org/t/first-part-benchmarking-medium-data-tools/28260 "2019-09-01T21:41:51Z")

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I compared and contrast JuliaDB with Dask and disk.frame. http://diskframe.com/articles/vs-dask-juliadb.html Probably more to come, but JuliaDB needs to mature before it can be a contender in these benchmarks.

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## [How to discover what functions can be called on a type](https://discourse.julialang.org/t/how-to-discover-what-functions-can-be-called-on-a-type/28236)

<div class="topic-metadata">

**Author:** [@jtf621](https://discourse.julialang.org/u/jtf621)\
**Replies:** 4\
**Last updated:** [September 1, 2019, 8:16pm UTC](https://discourse.julialang.org/t/how-to-discover-what-functions-can-be-called-on-a-type/28236 "2019-09-01T20:16:22Z")

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What are the different ways using a Julia shell to discover what functions can be called on a type? I am learning Julia as an experienced Python programmer. In python, I would open ipython, instantiate a variable of th…

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