# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=977

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**Page:** 978

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## [Deprecation warning even after \`using\` statement (0.7)](https://discourse.julialang.org/t/deprecation-warning-even-after-using-statement-0-7/11013)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 1\
**Last updated:** [May 19, 2018, 5:07pm UTC](https://discourse.julialang.org/t/deprecation-warning-even-after-using-statement-0-7/11013 "2018-05-19T17:07:42Z")

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I’m surprised by the deprecation warning… Is that proper behavior? julia\> using Distributed julia\> @fetch ERROR: LoadError: WARNING: Base.@fetch is deprecated: it has been moved to the standard library package \`Distrib…

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## [No badge for my package in pkg.julialang.org](https://discourse.julialang.org/t/no-badge-for-my-package-in-pkg-julialang-org/11011)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 0\
**Last updated:** [May 19, 2018, 3:47pm UTC](https://discourse.julialang.org/t/no-badge-for-my-package-in-pkg-julialang-org/11011 "2018-05-19T15:47:19Z")

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Hi guys! The badge for my package ReferenceFrameRotations is not available in https://pkg.julialang.org/detail/ReferenceFrameRotations for Julia v0.6. Is there anything I can do to fix this?

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## [Worker status](https://discourse.julialang.org/t/worker-status/11007)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 1\
**Last updated:** [May 19, 2018, 9:32am UTC](https://discourse.julialang.org/t/worker-status/11007 "2018-05-19T09:32:14Z")

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Is there any way to find out the current status of each worker process, whether they are currently available or busy?

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## [Possible Bug with push! and overwriting array](https://discourse.julialang.org/t/possible-bug-with-push-and-overwriting-array/11004)

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**Author:** [@RCSalomao](https://discourse.julialang.org/u/RCSalomao)\
**Replies:** 5\
**Last updated:** [May 18, 2018, 9:53pm UTC](https://discourse.julialang.org/t/possible-bug-with-push-and-overwriting-array/11004 "2018-05-18T21:53:14Z")

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Hello everyone. I have searched through the forums and haven’t found similar situation, so I am posting here to see if this is a bug or intended feature. Without further ado, I am posting a minimal working example (I am…

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## [Method of Line with DifferentialEquations.jl](https://discourse.julialang.org/t/method-of-line-with-differentialequations-jl/11000)

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**Author:** [@matthieu](https://discourse.julialang.org/u/matthieu)\
**Replies:** 5\
**Last updated:** [May 18, 2018, 7:52pm UTC](https://discourse.julialang.org/t/method-of-line-with-differentialequations-jl/11000 "2018-05-18T19:52:17Z")

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What algorithm/option in DifferentialEquations should I choose to solve efficiently a large and stiff system of ODE (a system of 100 to 10\_000 say) when I am only interested in the value of the stationary solution (i.e …

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## [Where {T\<:ConcreteType}](https://discourse.julialang.org/t/where-t-concretetype/11002)

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**Author:** [@rakeshvar](https://discourse.julialang.org/u/rakeshvar)\
**Replies:** 2\
**Last updated:** [May 18, 2018, 7:43pm UTC](https://discourse.julialang.org/t/where-t-concretetype/11002 "2018-05-18T19:43:18Z")

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Should n’t the two methods of f in the example below conflict? abstract type AbstractA end struct A \<: AbstractA data::Int end f(a::T) where {T\<:A} = (T, a.data) f(A(2)) # (A, 2) f(a::A) = ("A", a.data) f(A(2)) # ("…

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## [DiffEqDiffTools - addtional variables in objective function](https://discourse.julialang.org/t/diffeqdifftools-addtional-variables-in-objective-function/10965)

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**Author:** [@waldoc](https://discourse.julialang.org/u/waldoc)\
**Replies:** 2\
**Last updated:** [May 18, 2018, 4:38am UTC](https://discourse.julialang.org/t/diffeqdifftools-addtional-variables-in-objective-function/10965 "2018-05-18T04:38:07Z")

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Hi, I have found DiffEqDiffTools.finite\_difference\_jacobian to be quite useful, thanks to the devs :smile: I just have a question regarding passing additional variables in the objective function. The standard format wou…

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## [Creating presentation slides using remark.js](https://discourse.julialang.org/t/creating-presentation-slides-using-remark-js/10284)

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**Author:** [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Replies:** 12\
**Last updated:** [May 17, 2018, 10:05am UTC](https://discourse.julialang.org/t/creating-presentation-slides-using-remark-js/10284 "2018-05-17T10:05:23Z")

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I asked my department members (a Statistics department) what their preferred methods for creating slides for a talk were. The most popular answer was the xaringan package for R, which builds on remark.js. I plan to try…

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## [How to set julia startup options in Jupyter notebook?](https://discourse.julialang.org/t/how-to-set-julia-startup-options-in-jupyter-notebook/10998)

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**Author:** [@ronubi](https://discourse.julialang.org/u/ronubi)\
**Replies:** 3\
**Last updated:** [May 18, 2018, 5:21pm UTC](https://discourse.julialang.org/t/how-to-set-julia-startup-options-in-jupyter-notebook/10998 "2018-05-18T17:21:08Z")

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Are there Julia commands or environment settings that I can put at the top of a notebook (.ipynb) file, or put in .juliarc.jl, to get the same effect as launching julia from the command line with various option switches? …

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## [Power function with Integer ( x^4 much slower than x\*x\*x\*x )](https://discourse.julialang.org/t/power-function-with-integer-x-4-much-slower-than-x-x-x-x/10985)

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**Author:** [@JonasIsensee](https://discourse.julialang.org/u/JonasIsensee)\
**Replies:** 12\
**Last updated:** [May 18, 2018, 2:41pm UTC](https://discourse.julialang.org/t/power-function-with-integer-x-4-much-slower-than-x-x-x-x/10985 "2018-05-18T14:41:49Z")

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Hey there! I have a question. I need to calculate the following in a hot-loop: ω(d, dmax) = (1-(d/dmax)^2)^4 I benchmarked different versions of this and found the following using BenchmarkTools d = rand(10000) dm …

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## [What's not threadsafe?](https://discourse.julialang.org/t/whats-not-threadsafe/10984)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 11\
**Last updated:** [May 18, 2018, 1:11pm UTC](https://discourse.julialang.org/t/whats-not-threadsafe/10984 "2018-05-18T13:11:34Z")

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Hi all, I am looking for a list of things that are not safe to do inside a Threads.@threads loop. I am aware that this is as high-level as it gets, and I am sorry about that. For example, I realized myself that I canno…

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## [Request help in understanding why certain operations in a generated function lead to a \`MethodError\` but are fine outside the generated function](https://discourse.julialang.org/t/request-help-in-understanding-why-certain-operations-in-a-generated-function-lead-to-a-methoderror-but-are-fine-outside-the-generated-function/10980)

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**Author:** [@zygmuntszpak](https://discourse.julialang.org/u/zygmuntszpak)\
**Replies:** 1\
**Last updated:** [May 18, 2018, 8:50am UTC](https://discourse.julialang.org/t/request-help-in-understanding-why-certain-operations-in-a-generated-function-lead-to-a-methoderror-but-are-fine-outside-the-generated-function/10980 "2018-05-18T08:50:58Z")

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Hi all, I’m working on adding more specializations to kron for StaticArray and StaticVector types as part of this pull request: Adds more Kronecker product specialisations by zygmuntszpak · Pull Request #407 · JuliaArra…

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## [Help with LSTM on Flux.jl](https://discourse.julialang.org/t/help-with-lstm-on-flux-jl/10976)

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**Author:** [@rcnlee](https://discourse.julialang.org/u/rcnlee)\
**Replies:** 0\
**Last updated:** [May 18, 2018, 5:36am UTC](https://discourse.julialang.org/t/help-with-lstm-on-flux-jl/10976 "2018-05-18T05:36:12Z")

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Hello, I’m trying to figure out what’s wrong with my Flux LSTM model, which is a chain of LSTM, Dense, and softmax. The problem that I’m seeing is that the Dense grads are fine, but I get NaNs for all the LSTM gradients…

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## [Splat-to-append to tuple-of-arrays, or push! on array-of-arrays?](https://discourse.julialang.org/t/splat-to-append-to-tuple-of-arrays-or-push-on-array-of-arrays/10961)

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**Author:** [@ronubi](https://discourse.julialang.org/u/ronubi)\
**Replies:** 4\
**Last updated:** [May 17, 2018, 11:51pm UTC](https://discourse.julialang.org/t/splat-to-append-to-tuple-of-arrays-or-push-on-array-of-arrays/10961 "2018-05-17T23:51:13Z")

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I’m writing a function that needs to return a variable-length collection of arrays (depending on parameters in a file as well as optional function arguments). Each array may also have a different size. I can return the c…

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## [Find unique row in DataFrame](https://discourse.julialang.org/t/find-unique-row-in-dataframe/10945)

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**Author:** [@babaq](https://discourse.julialang.org/u/babaq)\
**Replies:** 5\
**Last updated:** [May 17, 2018, 9:29pm UTC](https://discourse.julialang.org/t/find-unique-row-in-dataframe/10945 "2018-05-17T21:29:20Z")

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Hi All, I am finding unique rows in a DataFrame and get number of repeat of unique rows, I could get by this: t=DataFrame(a=rand(1:5,20),b=rand(\[:x,:y,:z\],20)) ut=unique(t) Int\[countnz(\[t\[j,:\]==ut\[i,:\] for j in 1:size…

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## [Read data from excel starting from second row](https://discourse.julialang.org/t/read-data-from-excel-starting-from-second-row/10940)

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**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 5\
**Last updated:** [May 17, 2018, 4:42pm UTC](https://discourse.julialang.org/t/read-data-from-excel-starting-from-second-row/10940 "2018-05-17T16:42:29Z")

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I’m trying to read data in an excel workbook that starts on the second row. Using ExcelFiles, I can I read into a dataframe if the data starts on the first row DataFrame(load(fname, "sheetname") But I’m not sure what t…

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## ["Correct" way to document methods using \`where\` in the declaration?](https://discourse.julialang.org/t/correct-way-to-document-methods-using-where-in-the-declaration/10943)

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**Author:** [@tpoisot](https://discourse.julialang.org/u/tpoisot)\
**Replies:** 2\
**Last updated:** [May 17, 2018, 3:03pm UTC](https://discourse.julialang.org/t/correct-way-to-document-methods-using-where-in-the-declaration/10943 "2018-05-17T15:03:55Z")

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I have a function whose declaration starts with function union(X::T, Y::T) where {T\<:BipartiteNetwork} I was wondering if there is a community standard about how to write the docstring for this method? I have currently …

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## [How does broadcast! work ? Tips for memory efficiency while using 'kron'](https://discourse.julialang.org/t/how-does-broadcast-work-tips-for-memory-efficiency-while-using-kron/10957)

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**Author:** [@amitjamadagni](https://discourse.julialang.org/u/amitjamadagni)\
**Replies:** 1\
**Last updated:** [May 17, 2018, 2:55pm UTC](https://discourse.julialang.org/t/how-does-broadcast-work-tips-for-memory-efficiency-while-using-kron/10957 "2018-05-17T14:55:40Z")

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I was trying to use broadcast! in place of broadcast in the following code : function \_tensor\_product\_(st) ten = st\[1\] for s in st\[2:end\] ten = kron(ten, s) end return ten end @noinline functio…

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## [How to force mixed-type array of just ints and floats?](https://discourse.julialang.org/t/how-to-force-mixed-type-array-of-just-ints-and-floats/10934)

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**Author:** [@ronubi](https://discourse.julialang.org/u/ronubi)\
**Replies:** 4\
**Last updated:** [May 16, 2018, 8:26pm UTC](https://discourse.julialang.org/t/how-to-force-mixed-type-array-of-just-ints-and-floats/10934 "2018-05-16T20:26:09Z")

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I’d like to store a table as a mixed-type numeric array - just ints and floats. If I use \[brackets\] to initialize a vector of numeric values, Julia promotes the ints to floats and returns an array of floats. If I includ…

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## [InexactError() when running Pkg.test("GLVisualize") with VirtualGL](https://discourse.julialang.org/t/inexacterror-when-running-pkg-test-glvisualize-with-virtualgl/10829)

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**Author:** [@Quincy\_Wofford](https://discourse.julialang.org/u/Quincy_Wofford)\
**Replies:** 5\
**Last updated:** [May 16, 2018, 12:54pm UTC](https://discourse.julialang.org/t/inexacterror-when-running-pkg-test-glvisualize-with-virtualgl/10829 "2018-05-16T12:54:14Z")

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I’m running Julia with VirtualGL on a remote visualization node, and when I attempt to run Pkg.test(“GLVisualize”) I get an “Inexact error()”. Not sure if this could be related to VGL, but I thought I’d mention it. Other…

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## [Garbage collection of Julia code in C++](https://discourse.julialang.org/t/garbage-collection-of-julia-code-in-c/10894)

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**Author:** [@vitreo12](https://discourse.julialang.org/u/vitreo12)\
**Replies:** 16\
**Last updated:** [May 16, 2018, 10:33am UTC](https://discourse.julialang.org/t/garbage-collection-of-julia-code-in-c/10894 "2018-05-16T10:33:19Z")

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Hello everyone, I have a trivial question regarding the garbage collection for the c api of Julia. I am currently embedding Julia in a C++ class, and I need to access different mutable structs that I create in the C++ c…

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## [Cannot install CUDAnative with Pkg3 (Pkg can)](https://discourse.julialang.org/t/cannot-install-cudanative-with-pkg3-pkg-can/10865)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 6\
**Last updated:** [May 16, 2018, 6:37am UTC](https://discourse.julialang.org/t/cannot-install-cudanative-with-pkg3-pkg-can/10865 "2018-05-16T06:37:49Z")

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I tried Pkg3 with a local built master branch. But I cannot install CUDAnative with it. It seems that the version does not match? But I can install it with Pkg. Here is the error: julia\> Pkg3.add("CuArrays") Updating…

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## [Improve the performance of multiplication of an arbitrary number of matrices](https://discourse.julialang.org/t/improve-the-performance-of-multiplication-of-an-arbitrary-number-of-matrices/10835)

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**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 36\
**Last updated:** [May 16, 2018, 3:50am UTC](https://discourse.julialang.org/t/improve-the-performance-of-multiplication-of-an-arbitrary-number-of-matrices/10835 "2018-05-16T03:50:46Z")

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Hi guys! I need to make a function that multiplies an arbitrary number of matrices. My current attempt is the following: @inline function compose\_rotation(D1::Matrix, Ds::Matrix...) for Di in Ds D1 = Di\*D1 …

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## [Juliaism for vector within vector for arithmetic operations?](https://discourse.julialang.org/t/juliaism-for-vector-within-vector-for-arithmetic-operations/10915)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 5\
**Last updated:** [May 15, 2018, 9:58pm UTC](https://discourse.julialang.org/t/juliaism-for-vector-within-vector-for-arithmetic-operations/10915 "2018-05-15T21:58:16Z")

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I would like to create one array, unnested, calculated from various arithmetic vector operations. this is easier to illustrate than to describe. julia\> 10 + \[ -1, +1\]\*2 ## ok 2-element Array{Int64,1}: 8 12 julia\> …

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## [Choose a file interactively](https://discourse.julialang.org/t/choose-a-file-interactively/10910)

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**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 3\
**Last updated:** [May 15, 2018, 5:12pm UTC](https://discourse.julialang.org/t/choose-a-file-interactively/10910 "2018-05-15T17:12:25Z")

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In R, the function file.choose() exists to choose files interactively. This is nice when sharing code with someone who is not a programmer. Is there anything similar in Julia?

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## [Windows COM Client and sending emails through Outlook](https://discourse.julialang.org/t/windows-com-client-and-sending-emails-through-outlook/10887)

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**Author:** [@jacobcvt12](https://discourse.julialang.org/u/jacobcvt12)\
**Replies:** 2\
**Last updated:** [May 15, 2018, 2:04pm UTC](https://discourse.julialang.org/t/windows-com-client-and-sending-emails-through-outlook/10887 "2018-05-15T14:04:52Z")

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I currently have some R code that uses the package RDCOMClient, to send many generated emails through Microsoft Outlook. Is there any way to do this in Julia? I am not a Windows guy, so I don’t know if there might be som…

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## [The Broadcasting API and small Unions](https://discourse.julialang.org/t/the-broadcasting-api-and-small-unions/10896)

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**Author:** [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)\
**Replies:** 7\
**Last updated:** [May 15, 2018, 1:27pm UTC](https://discourse.julialang.org/t/the-broadcasting-api-and-small-unions/10896 "2018-05-15T13:27:27Z")

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After trying some near examples and the docs, I have not yet made the Broadcasting API do this. More explicit guidance is appreciated. abstract type OtherAbstractFloat \<: AbstractFloat end primitive type Float64a \<: Ot…

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## [Convert arrays to single precision](https://discourse.julialang.org/t/convert-arrays-to-single-precision/10903)

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**Author:** [@jebej](https://discourse.julialang.org/u/jebej)\
**Replies:** 6\
**Last updated:** [May 15, 2018, 12:48pm UTC](https://discourse.julialang.org/t/convert-arrays-to-single-precision/10903 "2018-05-15T12:48:02Z")

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Hello, I was wondering if there exists a function to convert objects, e.g. Array, SparseMatrix, special matrix types like Diagonal, etc…) to single precision. It should also handle converting objects of complex numbers …

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## [Computational experiments: organising different algorithms, their parameters and results](https://discourse.julialang.org/t/computational-experiments-organising-different-algorithms-their-parameters-and-results/10774)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 22\
**Last updated:** [May 15, 2018, 12:43pm UTC](https://discourse.julialang.org/t/computational-experiments-organising-different-algorithms-their-parameters-and-results/10774 "2018-05-15T12:43:10Z")

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Hi everyone, I am trying to run a bunch of computational experiments, different algorithms on different problems, using different sets of parameters each, pretty simply right? Well I am wondering what the best pipeline …

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## [Getting types right with functional programming](https://discourse.julialang.org/t/getting-types-right-with-functional-programming/10906)

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**Author:** [@Ward9250](https://discourse.julialang.org/u/Ward9250)\
**Replies:** 0\
**Last updated:** [May 15, 2018, 10:58am UTC](https://discourse.julialang.org/t/getting-types-right-with-functional-programming/10906 "2018-05-15T10:58:39Z")

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Hi, I want to process some records in an iterable, and wanted to try and do it in as functional style as possible: using BioSequences stream = open("tables3PITGs.fasta", "r") reader = FASTA.Reader(stream) # Set up reade…

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