# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=997

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**Page:** 998

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## [Error with JuliaPro 0.6.2](https://discourse.julialang.org/t/error-with-juliapro-0-6-2/8972)

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**Author:** [@v-i-s-h](https://discourse.julialang.org/u/v-i-s-h)\
**Replies:** 0\
**Last updated:** [February 10, 2018, 12:02pm UTC](https://discourse.julialang.org/t/error-with-juliapro-0-6-2/8972 "2018-02-10T12:02:54Z")

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Hi, I downloaded latest JuliaPro for ubuntu linux JuliaPro-0.6.2.1\_mkl\_build-13. When I start Juno and try some Julia command in Console, I’m getting this error: INFO: Precompiling module Atom. ERROR: LoadError: LoadEr…

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## [WORD\_SIZE not defined](https://discourse.julialang.org/t/word-size-not-defined/8971)

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**Author:** [@John\_Hearns](https://discourse.julialang.org/u/John_Hearns)\
**Replies:** 5\
**Last updated:** [February 10, 2018, 10:01am UTC](https://discourse.julialang.org/t/word-size-not-defined/8971 "2018-02-10T10:01:36Z")

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I do not know how in the heck I arrived at this state… WORD\_SIZE is supposed to be an internal variable… Following lots of build problems on Windows 10 I removed the Julia 0.61 and 0.62 packages and deleted directories…

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## [Interpretation of memallocs returned by @timed](https://discourse.julialang.org/t/interpretation-of-memallocs-returned-by-timed/8968)

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**Author:** [@goerz](https://discourse.julialang.org/u/goerz)\
**Replies:** 0\
**Last updated:** [February 10, 2018, 1:54am UTC](https://discourse.julialang.org/t/interpretation-of-memallocs-returned-by-timed/8968 "2018-02-10T01:54:32Z")

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I was trying to find some information about the memory allocation counters that the @timed macro returns. These should probably be explained in the documentation of @timed. I did find some comments in the source code for…

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## [More strangeness: ReadOnlyMemoryError() in 0.6.2 (longish post)](https://discourse.julialang.org/t/more-strangeness-readonlymemoryerror-in-0-6-2-longish-post/8958)

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**Author:** [@Stephen\_Vavasis](https://discourse.julialang.org/u/Stephen_Vavasis)\
**Replies:** 0\
**Last updated:** [February 9, 2018, 6:40pm UTC](https://discourse.julialang.org/t/more-strangeness-readonlymemoryerror-in-0-6-2-longish-post/8958 "2018-02-09T18:40:48Z")

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Earlier I reported a mysterious ReadOnlyMemoryError() in 0.6.2 under linux only. Someone else recently posted another problem with ReadOnlyMemoryError(), I decided to dig a bit deeper into my example, and the Julia beha…

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## [Library for finding fixed points of a function?](https://discourse.julialang.org/t/library-for-finding-fixed-points-of-a-function/8932)

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**Author:** [@jlperla](https://discourse.julialang.org/u/jlperla)\
**Replies:** 5\
**Last updated:** [February 9, 2018, 5:03pm UTC](https://discourse.julialang.org/t/library-for-finding-fixed-points-of-a-function/8932 "2018-02-09T17:03:07Z")

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A large number of algorithms in my field involve finding the fixed point of an operator. Are there any good libraries out there that do this (i.e. properly generic, testing out corner cases, etc.) Of course, a simple v…

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## [As simple as possible from the website, extract the raw text?](https://discourse.julialang.org/t/as-simple-as-possible-from-the-website-extract-the-raw-text/8697)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 4\
**Last updated:** [February 9, 2018, 4:16pm UTC](https://discourse.julialang.org/t/as-simple-as-possible-from-the-website-extract-the-raw-text/8697 "2018-02-09T16:16:30Z")

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As simple as possible from the website, extract the raw text ? Paul

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## [strange/misleading function signature in error messages when using named parameters](https://discourse.julialang.org/t/strange-misleading-function-signature-in-error-messages-when-using-named-parameters/8949)

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**Author:** [@mkaut](https://discourse.julialang.org/u/mkaut)\
**Replies:** 9\
**Last updated:** [February 9, 2018, 4:01pm UTC](https://discourse.julialang.org/t/strange-misleading-function-signature-in-error-messages-when-using-named-parameters/8949 "2018-02-09T16:01:06Z")

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I wrote a function with the following signature: function setOptimStatus(patientID::Int, status::String; rcProject::PyObject=0, repeatInst::Int=0). When called with two parameters, I get the following error message: ER…

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## [Accelerate compiler start time](https://discourse.julialang.org/t/accelerate-compiler-start-time/8951)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 3\
**Last updated:** [February 9, 2018, 2:21pm UTC](https://discourse.julialang.org/t/accelerate-compiler-start-time/8951 "2018-02-09T14:21:05Z")

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I am developing a CLI package CLI.jl, but it seems that the start time of the compiler makes a CLI script slower than a Python script or an executable. (precompile is on) I tried to use static-julia to compile it to an …

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## [To ~~not~~ shell out](https://discourse.julialang.org/t/to-not-shell-out/8929)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 14\
**Last updated:** [February 9, 2018, 2:02pm UTC](https://discourse.julialang.org/t/to-not-shell-out/8929 "2018-02-09T14:02:05Z")

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Related to this topic, I’d like to read the modification time in the metadata of images. Right now I can do this by “shelling out” and using exiftool. While this works, it’s painfully slow (when I need to process hundred…

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## [Calling Cython](https://discourse.julialang.org/t/calling-cython/8934)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 2\
**Last updated:** [February 9, 2018, 3:13am UTC](https://discourse.julialang.org/t/calling-cython/8934 "2018-02-09T03:13:51Z")

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I had some thoughts about wrapping SpaCy, SpaCy is a python library for NLP. Its 90% Cython, rather than actually being python. So I have a bunch of .so compiled shared objects. I am wondering if I can ccall into fun…

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## [Julia script segfault on errors](https://discourse.julialang.org/t/julia-script-segfault-on-errors/8484)

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**Author:** [@nico202](https://discourse.julialang.org/u/nico202)\
**Replies:** 3\
**Last updated:** [February 9, 2018, 2:21am UTC](https://discourse.julialang.org/t/julia-script-segfault-on-errors/8484 "2018-02-09T02:21:23Z")

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Hi, I have a strange behaviour with julia on NixOS REPL: versioninfo() Julia Version 0.6.0 Commit 903644385b\* (2017-06-19 13:05 UTC) println(undef) ERROR: UndefVarError: undef not defined Script: cat test.jl p…

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## [Large Scale Software Design and Guidelines](https://discourse.julialang.org/t/large-scale-software-design-and-guidelines/8925)

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**Author:** [@marcello](https://discourse.julialang.org/u/marcello)\
**Replies:** 8\
**Last updated:** [February 9, 2018, 12:17am UTC](https://discourse.julialang.org/t/large-scale-software-design-and-guidelines/8925 "2018-02-09T00:17:33Z")

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I’ve done an application in C++ that is taking some million lines of code. And I’ve paid the price. By starting reading the book ‘Large Scale Software Design - John Lakos’ I can see I made different mistakes, which I d…

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## [Type-unstable keyword constructor on parameterized type](https://discourse.julialang.org/t/type-unstable-keyword-constructor-on-parameterized-type/8852)

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**Author:** [@tomerarnon](https://discourse.julialang.org/u/tomerarnon)\
**Replies:** 5\
**Last updated:** [February 8, 2018, 7:46pm UTC](https://discourse.julialang.org/t/type-unstable-keyword-constructor-on-parameterized-type/8852 "2018-02-08T19:46:27Z")

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I have a parameterized struct for which I would like to define a convenient modifying function which uses a preexisting object of that type. The most convenient and clearest way is obviously to define a keyword construct…

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## [Call Python functions from Julia / Lorenz Attractor Example](https://discourse.julialang.org/t/call-python-functions-from-julia-lorenz-attractor-example/8905)

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**Author:** [@burfel](https://discourse.julialang.org/u/burfel)\
**Replies:** 5\
**Last updated:** [February 8, 2018, 5:49pm UTC](https://discourse.julialang.org/t/call-python-functions-from-julia-lorenz-attractor-example/8905 "2018-02-08T17:49:19Z")

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Hello, I was wondering how I best get Python functions running in Julia. The Lorenz attractor example in http://docs.juliaplots.org/latest/ isn’t working for me. The error message I get is The Python package mpl\_too…

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## [Example Iris Dataset not running](https://discourse.julialang.org/t/example-iris-dataset-not-running/8906)

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**Author:** [@burfel](https://discourse.julialang.org/u/burfel)\
**Replies:** 6\
**Last updated:** [February 8, 2018, 3:58pm UTC](https://discourse.julialang.org/t/example-iris-dataset-not-running/8906 "2018-02-08T15:58:35Z")

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Does anyone get the Iris Dataset on Home · Plots running?

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## [Julia Graphics Library](https://discourse.julialang.org/t/julia-graphics-library/8789)

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**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 6\
**Last updated:** [February 8, 2018, 3:23pm UTC](https://discourse.julialang.org/t/julia-graphics-library/8789 "2018-02-08T15:23:07Z")

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Are there any native Julia libraries for low-level graphics? Or are all options wrappers for other graphics libraries (such as OpenGL)?

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## [How to Kalman filter](https://discourse.julialang.org/t/how-to-kalman-filter/8745)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 16\
**Last updated:** [February 8, 2018, 2:41pm UTC](https://discourse.julialang.org/t/how-to-kalman-filter/8745 "2018-02-08T14:41:52Z")

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I need to improve on estimated locations of a moving object using prior knowledge about its speed (speed changes are small) and angular speed (its direction doesn’t change much either). For background, this is a continua…

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## [BigFloat performance, allocates like crazy!](https://discourse.julialang.org/t/bigfloat-performance-allocates-like-crazy/8892)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 10\
**Last updated:** [February 7, 2018, 10:50pm UTC](https://discourse.julialang.org/t/bigfloat-performance-allocates-like-crazy/8892 "2018-02-07T22:50:43Z")

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I have a program which allocates less than 35 MB and takes under 2 seconds with Float64 and Float32, but allocates 350 GB and takes more than 10 minutes with BigFloat, is this expected? The code is seemingly type stable.…

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## [C null pointer to custom type](https://discourse.julialang.org/t/c-null-pointer-to-custom-type/8885)

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**Author:** [@mopg](https://discourse.julialang.org/u/mopg)\
**Replies:** 8\
**Last updated:** [February 7, 2018, 4:34pm UTC](https://discourse.julialang.org/t/c-null-pointer-to-custom-type/8885 "2018-02-07T16:34:44Z")

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I am coupling to a C library and would like to pass null pointers to a function. However, I want to pass a null pointer of type Ptr{\<mytype\>}. When I do that I end up with a convert error, because C\_NULL of Ptr{Void}. It…

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## [Methods to reduce gc time?](https://discourse.julialang.org/t/methods-to-reduce-gc-time/8840)

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**Author:** [@RandomString123](https://discourse.julialang.org/u/RandomString123)\
**Replies:** 7\
**Last updated:** [February 7, 2018, 2:15pm UTC](https://discourse.julialang.org/t/methods-to-reduce-gc-time/8840 "2018-02-07T14:15:15Z")

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I have finally gotten some code I translated from R working. It is by no means optimized, and it is my first julia code, so I didn’t expect great performance but it is significantly slower than I would have expected. I…

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## [VS code triggers anti-malware](https://discourse.julialang.org/t/vs-code-triggers-anti-malware/8864)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 12\
**Last updated:** [February 7, 2018, 3:10pm UTC](https://discourse.julialang.org/t/vs-code-triggers-anti-malware/8864 "2018-02-07T15:10:35Z")

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Version 1.19.3 Commit 7c4205b5c6e52a53b81c69d2b2dc8a627abaa0ba Date 2018-01-25T10:36:34.867Z Shell 1.7.9 Renderer 58.0.3029.110 Node 7.9.0 Architecture x64 Every time I do something in the terminal anti-malware ki…

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## [Is the Julia linear algebra multithreaded?](https://discourse.julialang.org/t/is-the-julia-linear-algebra-multithreaded/8487)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 6\
**Last updated:** [February 7, 2018, 2:31pm UTC](https://discourse.julialang.org/t/is-the-julia-linear-algebra-multithreaded/8487 "2018-02-07T14:31:05Z")

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Is the Julia linear algebra multithreaded? I think I read somewhere that it isn’t, but I can’t find that text anymore. Does anyone know for sure?

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## [Plotting + Accessibility](https://discourse.julialang.org/t/plotting-accessibility/8873)

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**Author:** [@sdmcallister](https://discourse.julialang.org/u/sdmcallister)\
**Replies:** 8\
**Last updated:** [February 7, 2018, 10:23am UTC](https://discourse.julialang.org/t/plotting-accessibility/8873 "2018-02-07T10:23:47Z")

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I am wondering if any Julia users who are producing plots, dashboards, or similar products are required to meet accessibility standards (either set by their organization or broader regulatory body)? By accessibility, I m…

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## [LaTeX in docstrings not rendering](https://discourse.julialang.org/t/latex-in-docstrings-not-rendering/8867)

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**Author:** [@Bernard\_GODARD](https://discourse.julialang.org/u/Bernard_GODARD)\
**Replies:** 5\
**Last updated:** [February 7, 2018, 8:02am UTC](https://discourse.julialang.org/t/latex-in-docstrings-not-rendering/8867 "2018-02-07T08:02:43Z")

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I have had a look at and https://docs.julialang.org/en/stable/manual/documentation.html But I cannot get math formula to be rendered whether my doc is built by Travis or on my local machine using mkdocs. The doctrin…

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## [log(N) algo for sampling from vector](https://discourse.julialang.org/t/log-n-algo-for-sampling-from-vector/8713)

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**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 5\
**Last updated:** [February 7, 2018, 4:59am UTC](https://discourse.julialang.org/t/log-n-algo-for-sampling-from-vector/8713 "2018-02-07T04:59:24Z")

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Hi, I am using the following piece of code using StatsBase pf = StatsBase.Weights(rand(10)) e = sample(pf) Upon using @which sample(pf), one gets sample(wv::StatsBase.AbstractWeights) in StatsBase at .../StatsBase/sr…

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## [Keyword argument and type parameter error - triangular dispatch](https://discourse.julialang.org/t/keyword-argument-and-type-parameter-error-triangular-dispatch/8870)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 2\
**Last updated:** [February 6, 2018, 7:34pm UTC](https://discourse.julialang.org/t/keyword-argument-and-type-parameter-error-triangular-dispatch/8870 "2018-02-06T19:34:13Z")

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The following errors: julia\> f(a::Tx; b::T=0.1) where {T, Tx\<:AbstractVector{T}} = a .\* b ERROR: UndefVarError: T not defined but it makes sense not to. What do you think? These expectedly go through: julia\> f(a::Tx,…

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## [Merging triangles in mesh?](https://discourse.julialang.org/t/merging-triangles-in-mesh/8741)

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**Author:** [@mlhetland](https://discourse.julialang.org/u/mlhetland)\
**Replies:** 2\
**Last updated:** [February 6, 2018, 2:58pm UTC](https://discourse.julialang.org/t/merging-triangles-in-mesh/8741 "2018-02-06T14:58:04Z")

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Is there some existing library with functionality for merging triangles (or other faces) with (essentially) the same angles into single polygonal faces (based on GeometryTypes.jl, for example)? Trying to generate line-dr…

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## [Use of \`pointer\`](https://discourse.julialang.org/t/use-of-pointer/8849)

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**Author:** [@foobar\_lv2](https://discourse.julialang.org/u/foobar_lv2)\
**Replies:** 19\
**Last updated:** [February 6, 2018, 12:45pm UTC](https://discourse.julialang.org/t/use-of-pointer/8849 "2018-02-06T12:45:31Z")

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Split from A plea for int overflow checking as the default - #63 by Jean\_Michel I am not sure this would be significantly better in the current state of the compiler. I haven’t looked into the implementation of BigInt,…

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## [Next Juliabox faiing on RCall](https://discourse.julialang.org/t/next-juliabox-faiing-on-rcall/8760)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [February 6, 2018, 9:55am UTC](https://discourse.julialang.org/t/next-juliabox-faiing-on-rcall/8760 "2018-02-06T09:55:35Z")

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Just tried using RCall on next.juliabox.com and it gave the following error. Is the version of R too old for the new package of RCall.jl? INFO: Precompiling module RCall. WARNING: Method definition promote\_rule(Type{T},…

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## [Reversed Arrays](https://discourse.julialang.org/t/reversed-arrays/8860)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 3\
**Last updated:** [February 6, 2018, 8:42am UTC](https://discourse.julialang.org/t/reversed-arrays/8860 "2018-02-06T08:42:42Z")

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Is there a package that implements an array type where the index is reversed? I have an array that I would normally reverse the order but I don’t really want to incur an extra allocation cost or performance hit. So it …

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