# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1913

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

**Page:** 1914

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## [Another BLAS and Julia comparison](https://discourse.julialang.org/t/another-blas-and-julia-comparison/15411)

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**Author:** [@Noel\_Araujo](https://discourse.julialang.org/u/Noel_Araujo)\
**Replies:** 16\
**Last updated:** [September 27, 2019, 11:18am UTC](https://discourse.julialang.org/t/another-blas-and-julia-comparison/15411 "2019-09-27T11:18:53Z")

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Just for fun I did a direct translation of the BLAS function saspy, that is written in Fortran (You can found it here) into Julia. With two small optimizations (@inbounds and @threads) I can get almost the same speed of…

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## [Automatically cropping images](https://discourse.julialang.org/t/automatically-cropping-images/29235)

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**Author:** [@merckxiaan](https://discourse.julialang.org/u/merckxiaan)\
**Replies:** 6\
**Last updated:** [September 27, 2019, 3:45pm UTC](https://discourse.julialang.org/t/automatically-cropping-images/29235 "2019-09-27T15:45:58Z")

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Hello, I’ve got a directory filled with a couple of hundred images, similar to something like this: The problem is a lot of these images aren’t centered or don’t take up a lot of the space (e.g. a lot of excess whitesp…

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## [Re-installing Julia w/ v. 1.2.0 -- Plots doesn't compile](https://discourse.julialang.org/t/re-installing-julia-w-v-1-2-0-plots-doesnt-compile/29236)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 4\
**Last updated:** [September 27, 2019, 3:03pm UTC](https://discourse.julialang.org/t/re-installing-julia-w-v-1-2-0-plots-doesnt-compile/29236 "2019-09-27T15:03:35Z")

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After some problem with Julia vs. Python in Jypyter notebooks, I’m removing every trace of Python and Julia on my computers, and re-installing first Julia v. 1.2.0 with packages, and then Anaconda. \[I mainly use Julia, b…

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## [What is the recommended way to decorate an IO stream with a filter in Julia](https://discourse.julialang.org/t/what-is-the-recommended-way-to-decorate-an-io-stream-with-a-filter-in-julia/29226)

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**Author:** [@pszufe](https://discourse.julialang.org/u/pszufe)\
**Replies:** 1\
**Last updated:** [September 27, 2019, 1:34pm UTC](https://discourse.julialang.org/t/what-is-the-recommended-way-to-decorate-an-io-stream-with-a-filter-in-julia/29226 "2019-09-27T13:34:40Z")

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What is the recommended way to decorate a IO stream with a filter? One great example of stream decorators is CodecZlib.jl that provides compression and decompression decorators for output and input streams respectively. …

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## [Using Julia on Windows with strict group policy, can't install packages or load packages installed by localadmin](https://discourse.julialang.org/t/using-julia-on-windows-with-strict-group-policy-cant-install-packages-or-load-packages-installed-by-localadmin/29229)

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**Author:** [@jhelske](https://discourse.julialang.org/u/jhelske)\
**Replies:** 4\
**Last updated:** [September 27, 2019, 1:33pm UTC](https://discourse.julialang.org/t/using-julia-on-windows-with-strict-group-policy-cant-install-packages-or-load-packages-installed-by-localadmin/29229 "2019-09-27T13:33:00Z")

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In my work computer I have my normal user account and a separate localadmin account. After struggling with Atom and Julia installations (mostly Atom), I managed to get them working to some extent when I installed both on…

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## [\[ANN\] Chess.jl - A Julia chess programming library](https://discourse.julialang.org/t/ann-chess-jl-a-julia-chess-programming-library/29221)

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**Author:** [@Tord](https://discourse.julialang.org/u/Tord)\
**Replies:** 6\
**Last updated:** [September 27, 2019, 11:27am UTC](https://discourse.julialang.org/t/ann-chess-jl-a-julia-chess-programming-library/29221 "2019-09-27T11:27:48Z")

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I just published the first version of Chess.jl, a library for computer chess. This is my first Julia project, and I am not a real programmer, so much of the code probably looks amateurish, but it works and performs surpr…

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## [Conditional if else constraint in JuMP](https://discourse.julialang.org/t/conditional-if-else-constraint-in-jump/29177)

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**Author:** [@gopal2017](https://discourse.julialang.org/u/gopal2017)\
**Replies:** 2\
**Last updated:** [September 27, 2019, 11:13am UTC](https://discourse.julialang.org/t/conditional-if-else-constraint-in-jump/29177 "2019-09-27T11:13:35Z")

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Hi, I want to use conditional if else in JuMP. I have seen ConditionalJuMP at https://juliaobserver.com/packages/ConditionalJuMP. But it won’t work for julia v0.5.2 Please mention any package for indicator constraints. …

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## [Simple custom recurrent layer in Flux](https://discourse.julialang.org/t/simple-custom-recurrent-layer-in-flux/26740)

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**Author:** [@Rassibassi](https://discourse.julialang.org/u/Rassibassi)\
**Replies:** 2\
**Last updated:** [September 27, 2019, 10:45am UTC](https://discourse.julialang.org/t/simple-custom-recurrent-layer-in-flux/26740 "2019-09-27T10:45:36Z")

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Hi, I am looking into Flux and trying to understand the recurrent functionality. The following code defines a first order low pass filter with Flux.Recur. using Flux using Flux.Tracker c = 0.5 function LP(h, x) h…

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## [Issue with search system on julialang.org?](https://discourse.julialang.org/t/issue-with-search-system-on-julialang-org/28908)

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**Author:** [@klaff](https://discourse.julialang.org/u/klaff)\
**Replies:** 3\
**Last updated:** [September 27, 2019, 8:13am UTC](https://discourse.julialang.org/t/issue-with-search-system-on-julialang-org/28908 "2019-09-27T08:13:54Z")

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I’m seeing a weird behavior when searching the docs. I was looking for stuff on generator expressions. This seems to work okay. But if I type one more character I get which isn’t useful. And if I type a few mor…

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## [Web Socket Issue - halt with no error after write(TCPSocket)](https://discourse.julialang.org/t/web-socket-issue-halt-with-no-error-after-write-tcpsocket/29220)

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**Author:** [@Wednesday](https://discourse.julialang.org/u/Wednesday)\
**Replies:** 0\
**Last updated:** [September 27, 2019, 8:43am UTC](https://discourse.julialang.org/t/web-socket-issue-halt-with-no-error-after-write-tcpsocket/29220 "2019-09-27T08:43:55Z")

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Okay as a prerequisite I am new to the language and am likely doing something incorrectly. I am using the Sockets module from the standard library. I am writing a client side julia program that needs to read two Float6…

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## [Non-intuitive perf diff between \`matrix \* vector\`, \`matrix' \* vector\` and \`copy(matrix') \* vector\`](https://discourse.julialang.org/t/non-intuitive-perf-diff-between-matrix-vector-matrix-vector-and-copy-matrix-vector/29207)

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**Author:** [@jeremejevs](https://discourse.julialang.org/u/jeremejevs)\
**Replies:** 2\
**Last updated:** [September 27, 2019, 7:09am UTC](https://discourse.julialang.org/t/non-intuitive-perf-diff-between-matrix-vector-matrix-vector-and-copy-matrix-vector/29207 "2019-09-27T07:09:25Z")

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I’m using Julia 1.2. This is my test: a = rand(1000, 1000) b = a' c = copy(b) @btime a \* x setup=(x=rand(1000)) # 114.757 μs @btime b \* x setup=(x=rand(1000)) # 94.179 μs @btime c \* x setup=(x=rand(1000)) # 110.325 μs …

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## [Does Julia Need a C++ style \`static\` keyword?](https://discourse.julialang.org/t/does-julia-need-a-c-style-static-keyword/29176)

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**Author:** [@dataDiver](https://discourse.julialang.org/u/dataDiver)\
**Replies:** 21\
**Last updated:** [September 27, 2019, 5:01am UTC](https://discourse.julialang.org/t/does-julia-need-a-c-style-static-keyword/29176 "2019-09-27T05:01:28Z")

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I was wandering whether there is currently a way of representing C++ style static variables in Julia. I haven’t found out how and I think they are pretty useful - especially when dealing with lots of object instances tha…

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## [Correctly generate function from user input](https://discourse.julialang.org/t/correctly-generate-function-from-user-input/29214)

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**Author:** [@ry-dgel](https://discourse.julialang.org/u/ry-dgel)\
**Replies:** 1\
**Last updated:** [September 27, 2019, 3:07am UTC](https://discourse.julialang.org/t/correctly-generate-function-from-user-input/29214 "2019-09-27T03:07:54Z")

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Hello, I’m trying to put together a module for rapid fitting of data. I work in an experimental physics lab and want to make a tool that my collegues and I can use to bang out fits of large data sets efficiently. Ideal…

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## [Avoiding unnecessary mallocs while building then solving a linear system inside a loop can only be achieved by routines that modify in-place?](https://discourse.julialang.org/t/avoiding-unnecessary-mallocs-while-building-then-solving-a-linear-system-inside-a-loop-can-only-be-achieved-by-routines-that-modify-in-place/29210)

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**Author:** [@pedrohnv](https://discourse.julialang.org/u/pedrohnv)\
**Replies:** 2\
**Last updated:** [September 27, 2019, 2:50am UTC](https://discourse.julialang.org/t/avoiding-unnecessary-mallocs-while-building-then-solving-a-linear-system-inside-a-loop-can-only-be-achieved-by-routines-that-modify-in-place/29210 "2019-09-27T02:50:19Z")

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Hello, I have some functions that build a linear system. I then want to build and solve the system in a loop, while modifying a parameter. My first, straightforward, approach resulted in many allocations being done unne…

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## [Designating the axes for broadcasting](https://discourse.julialang.org/t/designating-the-axes-for-broadcasting/29203)

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**Author:** [@crinders](https://discourse.julialang.org/u/crinders)\
**Replies:** 2\
**Last updated:** [September 26, 2019, 5:11pm UTC](https://discourse.julialang.org/t/designating-the-axes-for-broadcasting/29203 "2019-09-26T17:11:00Z")

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I can’t find a way to designate the axes over which to broadcast. I looked at broadcast.jl and combine\_axes and I can’t make heads or tails of it. I just want to do julia\> T = randn((3,2,4)) 3×2×4 Array{Float64,3}: \[:,…

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## [Using PackageCompiler in windows](https://discourse.julialang.org/t/using-packagecompiler-in-windows/29199)

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**Author:** [@HBaghdadi1995](https://discourse.julialang.org/u/HBaghdadi1995)\
**Replies:** 2\
**Last updated:** [September 26, 2019, 4:14pm UTC](https://discourse.julialang.org/t/using-packagecompiler-in-windows/29199 "2019-09-26T16:14:17Z")

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Hi, I tried building a shared library based on hello.jl found here. It created the following files: - 7z.dll - libccalltest.dll - libgfortran-4.dll - libmpfr.dll - libssh2.dll - libwinpthread-1.dll - BugpointPasses.dll…

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## [Fatal error with freshly installed Julia 1.2 on MacOS](https://discourse.julialang.org/t/fatal-error-with-freshly-installed-julia-1-2-on-macos/29178)

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**Author:** [@CameronBieganek](https://discourse.julialang.org/u/CameronBieganek)\
**Replies:** 5\
**Last updated:** [September 26, 2019, 3:17pm UTC](https://discourse.julialang.org/t/fatal-error-with-freshly-installed-julia-1-2-on-macos/29178 "2019-09-26T15:17:43Z")

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I just installed Julia 1.2 on my MacBook Pro, but it keeps crashing: cbieganek@spmacpro90:~$ julia \_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_) | (\_) (\_) | \_ \_ \_…

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## [FourierAnalysis.jl - a package for the analysis of multivariate time-series in the frequency and time-frequency domain](https://discourse.julialang.org/t/fourieranalysis-jl-a-package-for-the-analysis-of-multivariate-time-series-in-the-frequency-and-time-frequency-domain/29157)

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**Author:** [@Marco-Congedo](https://discourse.julialang.org/u/Marco-Congedo)\
**Replies:** 6\
**Last updated:** [September 26, 2019, 8:10am UTC](https://discourse.julialang.org/t/fourieranalysis-jl-a-package-for-the-analysis-of-multivariate-time-series-in-the-frequency-and-time-frequency-domain/29157 "2019-09-26T08:10:32Z")

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Hello all, I wrote a package for performing the analysis of real multivariate time series both in the frequency domain and in the time-frequency domain, based on DSP.jl, FFTW.jl and AbstractFFTs.jl. In the frequ…

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## [Gadfly: adding line-styles to the plot legend](https://discourse.julialang.org/t/gadfly-adding-line-styles-to-the-plot-legend/29188)

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**Author:** [@mike\_k](https://discourse.julialang.org/u/mike_k)\
**Replies:** 4\
**Last updated:** [September 26, 2019, 2:36pm UTC](https://discourse.julialang.org/t/gadfly-adding-line-styles-to-the-plot-legend/29188 "2019-09-26T14:36:14Z")

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Dear community, I want to create a plot with several lines that have different line-styles (e.g., solid, dashed, dotted,…), and to add these styles to the legend of the plot (to fit for a black-white publication). Is th…

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## [IJulia... after removing Python](https://discourse.julialang.org/t/ijulia-after-removing-python/29111)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 12\
**Last updated:** [September 26, 2019, 2:04pm UTC](https://discourse.julialang.org/t/ijulia-after-removing-python/29111 "2019-09-26T14:04:18Z")

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I recently had problems with running some Python code (Spyder didn’t find the kernel, etc. – maybe because I had several Python versions installed). So in the end, I deleted every Python version on my computer, and re-in…

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## [\[ANN\] SimpleMock 0.1.0 - A basic mocking module](https://discourse.julialang.org/t/ann-simplemock-0-1-0-a-basic-mocking-module/29189)

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**Author:** [@christopher-dG](https://discourse.julialang.org/u/christopher-dG)\
**Replies:** 2\
**Last updated:** [September 26, 2019, 1:51pm UTC](https://discourse.julialang.org/t/ann-simplemock-0-1-0-a-basic-mocking-module/29189 "2019-09-26T13:51:29Z")

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Hello! I am happy to announce a little project of mine called SimpleMock.jl. It has a really simple API to help you test non-deterministic or hard-to-replicate function behaviours like randomness, networking, etc. usin…

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## [Julia Interview](https://discourse.julialang.org/t/julia-interview/29148)

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**Author:** [@DongLao](https://discourse.julialang.org/u/DongLao)\
**Replies:** 4\
**Last updated:** [September 26, 2019, 12:48pm UTC](https://discourse.julialang.org/t/julia-interview/29148 "2019-09-26T12:48:47Z")

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I’m going to an interview next week. Can you guys give me some tips on how to make a good impression?

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## [Array by reference](https://discourse.julialang.org/t/array-by-reference/29187)

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**Author:** [@alequa](https://discourse.julialang.org/u/alequa)\
**Replies:** 2\
**Last updated:** [September 26, 2019, 12:14pm UTC](https://discourse.julialang.org/t/array-by-reference/29187 "2019-09-26T12:14:30Z")

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Assigning a new type out of function prevents the compiler to assign the returned-type properly. In the example I show it just ends up returning ::Any. In my broader example it messes up within the function itself and t…

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## [Passing parameters and performances](https://discourse.julialang.org/t/passing-parameters-and-performances/29175)

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**Author:** [@alequa](https://discourse.julialang.org/u/alequa)\
**Replies:** 3\
**Last updated:** [September 26, 2019, 12:11pm UTC](https://discourse.julialang.org/t/passing-parameters-and-performances/29175 "2019-09-26T12:11:00Z")

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Hi, I am writing a simulator for spiking neural network. In the simulator I would like to use a loop like the one in the code Params = Dict{String,Union{Int,Bool}} function sim\_loop!(synapse\_params::Dict{String,Floa…

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## [@code\_warntype but for allocations?](https://discourse.julialang.org/t/code-warntype-but-for-allocations/29190)

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**Author:** [@cshenton](https://discourse.julialang.org/u/cshenton)\
**Replies:** 1\
**Last updated:** [September 26, 2019, 11:27am UTC](https://discourse.julialang.org/t/code-warntype-but-for-allocations/29190 "2019-09-26T11:27:36Z")

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Is there a similar macro to @code\_warntype for allocations? As in, given a function call (or function and tuple of input types), highlights any calls in the function that allocate, just as code\_warntype highlights sub ex…

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## [\[ANN\] HAML.jl - Ruby's favourite templating language comes to Julia](https://discourse.julialang.org/t/ann-haml-jl-rubys-favourite-templating-language-comes-to-julia/29066)

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**Author:** [@tkluck](https://discourse.julialang.org/u/tkluck)\
**Replies:** 6\
**Last updated:** [September 26, 2019, 10:05am UTC](https://discourse.julialang.org/t/ann-haml-jl-rubys-favourite-templating-language-comes-to-julia/29066 "2019-09-26T10:05:40Z")

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I just released an early version of HAML.jl - a Julia-dialect of Ruby’s HAML templating language. (The release is pending this merge request.) Thanks to Julia’s macros and code generation features, this package compiles…

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## [How to input path in run() and joinpath() on Windows](https://discourse.julialang.org/t/how-to-input-path-in-run-and-joinpath-on-windows/29183)

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**Author:** [@leejm516](https://discourse.julialang.org/u/leejm516)\
**Replies:** 4\
**Last updated:** [September 26, 2019, 9:46am UTC](https://discourse.julialang.org/t/how-to-input-path-in-run-and-joinpath-on-windows/29183 "2019-09-26T09:46:08Z")

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Hello, everybody! Today I have got in trouble with run() for putting the path from a string variable. It seems ok with … julia\> test = joinpath("~") "~" julia\> run(\`dir $test\`) %APPDATA% 3D\\ Objects AppData Applicati…

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## [Float64 comparison operator performance](https://discourse.julialang.org/t/float64-comparison-operator-performance/29179)

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**Author:** [@milesf](https://discourse.julialang.org/u/milesf)\
**Replies:** 8\
**Last updated:** [September 26, 2019, 8:39am UTC](https://discourse.julialang.org/t/float64-comparison-operator-performance/29179 "2019-09-26T08:39:38Z")

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I expect the performance of a \< b to be the same as Base.lt(Base.Forward, a, b) if all type information is known at compile time, but I’m observing a 2.5x difference with Float64. using BenchmarkTools using Random Rand…

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## [Solving "restricted by julia compatibility requirements to versions: uninstalled — no versions left"](https://discourse.julialang.org/t/solving-restricted-by-julia-compatibility-requirements-to-versions-uninstalled-no-versions-left/29068)

<div class="topic-metadata">

**Author:** [@blaiseli](https://discourse.julialang.org/u/blaiseli)\
**Replies:** 3\
**Last updated:** [September 26, 2019, 8:29am UTC](https://discourse.julialang.org/t/solving-restricted-by-julia-compatibility-requirements-to-versions-uninstalled-no-versions-left/29068 "2019-09-26T08:29:18Z")

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I have an application that I’m able to install in a singularity container based on julia 1.2, but now, I would like to install it in a container based on julia 1.0. I then had “Unsatisfiable requirements” issues for a p…

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## [Standard library or original for TerminalMenus](https://discourse.julialang.org/t/standard-library-or-original-for-terminalmenus/23160)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 8\
**Last updated:** [September 26, 2019, 8:15am UTC](https://discourse.julialang.org/t/standard-library-or-original-for-terminalmenus/23160 "2019-09-26T08:15:17Z")

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I want to use TerminalMenus in some minimal GUI app I’m developing. I can either use the original author’s version, or the one included in Julia’s standard libraries (documented here). I think they’re both really simila…

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