Le vendredi 20 novembre 2015 à 04:54 -0800, Michele Zaffalon a écrit : > Should `linspace` act as an array for `repeat`? Yes, the signature of repeat() is clearly too strict. This has been discussed at https://github.com/JuliaLang/julia/issues/12953
There was a clear support for this, but a decision would have to be taken regarding whether to use positional arguments instead of keyword arguments. Regards > On Wednesday, October 21, 2015 at 10:00:46 PM UTC+2, Art Kuo wrote: > > I don't think there is much to argue about, except perhaps names. > > `linspace` returns a range, but is otherwise a drop-in replacement > > for an array, and should act as one for any naive user, other than > > sometimes being faster and taking less memory. This is not hidden > > from the user, yet they need not be concerned about it. It just > > works. (The array might be better in some cases, I suspect rarely.) > > One might expect a `linspace` to show an array when typed into the > > REPL. With #13615, post-0.4 the user will see that it is a range > > and also "what they expect." > > It is true that `logspace` is an array and `linspace` is a range, > > and this is ugly. Perhaps there should be a `logrange` to go with > > `linrange`, or `logspace` should be modified to be a range. I do > > agree with these complaints. > > The name `logspace` probably comes from Matlab, but otherwise has > > no significance and is not a great name. Perhaps it's worth keeping > > around for that reason; perhaps it should be stashed into a Matlab > > module. > > As much as I was attracted here by the Matlab-alikeness, that can > > be a detriment. For example, Matlab overloads `diag` so you get two > > very different things for two different inputs. Whereas Mathematica > > has long, clear names, and `DiagonalMatrix` and `Diagonal` give a > > better clue what will happen. And as much as I love `eye`, > > `IdentityMatrix` is clearer. Other Matlab-isms: `tril`, `pcg`, > > `alim`, `shg`. > > > > > > On Wednesday, October 21, 2015 at 3:16:58 PM UTC-4, Stefan > > Karpinski wrote: > > > This thread is tragically long on opinions and short on arguments > > > backing them up. It occurs to me that we can write specialized > > > methods for collect(::LinSpace) that generate the collected > > > version more efficiently than generic iteration does, which > > > eliminates one of the potential arguments for just generating an > > > array. > > > > > > On Wednesday, October 21, 2015, Gabriel Gellner < > > > gabriel...@gmail.com> wrote: > > > > I agree with this downvote so much it hurts. The > > > > logspace/linspace is painfully ugly. linrange is the right name > > > > in my find for the iterator version. > > > > > > > > On Wednesday, 30 September 2015 10:31:55 UTC-7, Alex Ames > > > > wrote: > > > > > Another downvote on linspace returning a range object. It > > > > > seems odd for linspace and logspace to return different > > > > > types, and linrange provides the low-memory option where > > > > > needed. Numpy's `linspace` also returns an array object. > > > > > I ran into errors when trying to plot a function over a > > > > > linspace of x values, since plotting libs currently expect > > > > > vectors as arguments, not range objects. Easily fixed if you > > > > > know Julia well, but Matlab/Python converts may be stymied. > > > > > > > > > > On Wednesday, September 30, 2015 at 12:19:22 PM UTC-5, J Luis > > > > > wrote: > > > > > > I want to add my voice to the dislikers. Those are the type > > > > > > of surprises that are not welcome mainly for matlab users. > > > > > > > > > > > > quarta-feira, 30 de Setembro de 2015 às 16:53:57 UTC+1, > > > > > > Christoph Ortner escreveu: > > > > > > > I also strongly dislike the `linspace` change; I like the > > > > > > > idea though of having `linspace` and `linrange`, where > > > > > > > the former should give the array. > > > > > > > Christoph > > > > > > > > > > > > > > > > > > > > > On Wednesday, 30 September 2015 10:21:36 UTC+1, Michele > > > > > > > Zaffalon wrote: > > > > > > > > I just realize that the thread is about 0.3.11 and I am > > > > > > > > showing output for 0.4.0-rc2. Sorry for the noise. > > > > > > > > > > > > > > > > On Wed, Sep 30, 2015 at 11:17 AM, Michele Zaffalon < > > > > > > > > michele....@gmail.com> wrote: > > > > > > > > > > > > > > > > > > On Wed, Sep 30, 2015 at 9:50 AM, Milan Bouchet-Valat > > > > > > > > > <nali...@club.fr> wrote: > > > > > > > > > > Le mercredi 30 septembre 2015 à 08:55 +0200, > > > > > > > > > > Michele Zaffalon a écrit : > > > > > > > > > > > Just curious: linspace returns a Range object, > > > > > > > > > > but logspace returns a > > > > > > > > > > > vector because there is no much use case for a > > > > > > > > > > LogRange object? > > > > > > > > > > > > > > > > > > > > > > @feza: I have also seen the deprecation warning > > > > > > > > > > going away after a > > > > > > > > > > > couple of calls, but I am not sure why. If you > > > > > > > > > > restart Julia, the > > > > > > > > > > > deprecations reappear. > > > > > > > > > > Deprecation warnings are only printed once for each > > > > > > > > > > call place. The > > > > > > > > > > idea is that once you're aware of it, there's no > > > > > > > > > > point in nagging you. > > > > > > > > > > > > > > > > > > > > Anyway, that warning is most probably not related > > > > > > > > > > to linspace at all, > > > > > > > > > > but rather to the array concatenation syntax > > > > > > > > > > resulting in an effect > > > > > > > > > > equivalent to collect(). If you show us a piece of > > > > > > > > > > code that prints the > > > > > > > > > > warning, we can give you more details. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Regards > > > > > > > > > Sorry, you are right, I was referring to the > > > > > > > > > concatenation. > > > > > > > > > It prints it exaclty twice if I type it in the REPL, > > > > > > > > > it always prints it if I define it within a function > > > > > > > > > e.g. a() = [1:3]. > > > > > > > > > > > > > > > > > > C:\Users\michele.zaffalon>julia > > > > > > > > > _ > > > > > > > > > _ _ _(_)_ | A fresh approach to > > > > > > > > > technical computing > > > > > > > > > (_) | (_) (_) | Documentation: > > > > > > > > > http://docs.julialang.org > > > > > > > > > _ _ _| |_ __ _ | Type "?help" for help. > > > > > > > > > | | | | | | |/ _` | | > > > > > > > > > | | |_| | | | (_| | | Version 0.4.0-rc2 (2015-09 > > > > > > > > > -18 17:51 UTC) > > > > > > > > > _/ |\__'_|_|_|\__'_| | Official > > > > > > > > > http://julialang.org/ release > > > > > > > > > |__/ | x86_64-w64-mingw32 > > > > > > > > > > > > > > > > > > julia> [1:3] > > > > > > > > > WARNING: [a] concatenation is deprecated; use > > > > > > > > > collect(a) instead > > > > > > > > > in depwarn at deprecated.jl:73 > > > > > > > > > in oldstyle_vcat_warning at abstractarray.jl:29 > > > > > > > > > in vect at abstractarray.jl:32 > > > > > > > > > while loading no file, in expression starting on line > > > > > > > > > 0 > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > julia> [1:3] > > > > > > > > > WARNING: [a] concatenation is deprecated; use > > > > > > > > > collect(a) instead > > > > > > > > > in depwarn at deprecated.jl:73 > > > > > > > > > in oldstyle_vcat_warning at abstractarray.jl:29 > > > > > > > > > in vect at abstractarray.jl:32 > > > > > > > > > while loading no file, in expression starting on line > > > > > > > > > 0 > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > julia> [1:3] > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > julia> a() = [1:3] > > > > > > > > > a (generic function with 1 method) > > > > > > > > > > > > > > > > > > julia> a() > > > > > > > > > WARNING: [a] concatenation is deprecated; use > > > > > > > > > collect(a) instead > > > > > > > > > in depwarn at deprecated.jl:73 > > > > > > > > > in oldstyle_vcat_warning at abstractarray.jl:29 > > > > > > > > > in a at none:1 > > > > > > > > > while loading no file, in expression starting on line > > > > > > > > > 0 > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > julia> a() > > > > > > > > > WARNING: [a] concatenation is deprecated; use > > > > > > > > > collect(a) instead > > > > > > > > > in depwarn at deprecated.jl:73 > > > > > > > > > in oldstyle_vcat_warning at abstractarray.jl:29 > > > > > > > > > in a at none:1 > > > > > > > > > while loading no file, in expression starting on line > > > > > > > > > 0 > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > julia> a() > > > > > > > > > WARNING: [a] concatenation is deprecated; use > > > > > > > > > collect(a) instead > > > > > > > > > in depwarn at deprecated.jl:73 > > > > > > > > > in oldstyle_vcat_warning at abstractarray.jl:29 > > > > > > > > > in a at none:1 > > > > > > > > > while loading no file, in expression starting on line > > > > > > > > > 0 > > > > > > > > > 3-element Array{Int64,1}: > > > > > > > > > 1 > > > > > > > > > 2 > > > > > > > > > 3 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Wed, Sep 30, 2015 at 5:40 AM, feza < > > > > > > > > > > moham...@gmail.com> wrote: > > > > > > > > > > > > Strange it *was* giving me an error saying > > > > > > > > > > deprecated and that I > > > > > > > > > > > > should use collect, but now it's fine. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tuesday, September 29, 2015 at 10:28:12 PM > > > > > > > > > > UTC-4, Sheehan Olver > > > > > > > > > > > > wrote: > > > > > > > > > > > > > fez, I'm pretty sure the code works fine > > > > > > > > > > without the collect: > > > > > > > > > > > > > when exp is called on linspace it converts it > > > > > > > > > > to a vector. > > > > > > > > > > > > > Though the returned t will be linspace > > > > > > > > > > object. > > > > > > > > > > > > > > > > > > > > > > > > > > On Wednesday, September 30, 2015 at 12:10:55 > > > > > > > > > > PM UTC+10, feza > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > Here's the code I was using where I needed > > > > > > > > > > to use collect (I've > > > > > > > > > > > > > > been playing around with Julia, so any > > > > > > > > > > suggestions on this code > > > > > > > > > > > > > > for perf is welcome ;) ) . In general > > > > > > > > > > linspace (or the : > > > > > > > > > > > > > > notation) is also used commonly to lay a > > > > > > > > > > grid in space for > > > > > > > > > > > > > > solving a PDE for some other use cases. > > > > > > > > > > > > > > > > > > > > > > > > > > > > function gp(n) > > > > > > > > > > > > > > n = convert(Int,n) > > > > > > > > > > > > > > t0 = 0 > > > > > > > > > > > > > > tf = 5 > > > > > > > > > > > > > > t = collect( linspace(t0, tf, n+1) > > > > > > > > > > ) > > > > > > > > > > > > > > sigma = exp( -(t - t[1]) ) > > > > > > > > > > > > > > > > > > > > > > > > > > > > c = [sigma; sigma[(end-1):-1:2]] > > > > > > > > > > > > > > lambda = fft(c) > > > > > > > > > > > > > > eta = sqrt(lambda./(2*n)) > > > > > > > > > > > > > > > > > > > > > > > > > > > > Z = randn(2*n) + im*randn(2*n) > > > > > > > > > > > > > > x = real( fft( Z.*eta ) ) > > > > > > > > > > > > > > return (x, t) > > > > > > > > > > > > > > end > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tuesday, September 29, 2015 at 8:59:52 > > > > > > > > > > PM UTC-4, Stefan > > > > > > > > > > > > > > Karpinski wrote: > > > > > > > > > > > > > > > I'm curious why you need a vector rather > > > > > > > > > > than an object. Do > > > > > > > > > > > > > > > you mutate it after creating it? Having > > > > > > > > > > linspace return an > > > > > > > > > > > > > > > object instead of a vector was a bit of a > > > > > > > > > > unclear judgement > > > > > > > > > > > > > > > call so getting feedback would be good. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tuesday, September 29, 2015, Patrick > > > > > > > > > > Kofod Mogensen < > > > > > > > > > > > > > > > patrick....@gmail.com> wrote: > > > > > > > > > > > > > > > > No: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > julia> logspace(0,3,5) > > > > > > > > > > > > > > > > 5-element Array{Float64,1}: > > > > > > > > > > > > > > > > 1.0 > > > > > > > > > > > > > > > > 5.62341 > > > > > > > > > > > > > > > > 31.6228 > > > > > > > > > > > > > > > > 177.828 > > > > > > > > > > > > > > > > 1000.0 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tuesday, September 29, 2015 at > > > > > > > > > > 8:50:47 PM UTC-4, Luke > > > > > > > > > > > > > > > > Stagner wrote: > > > > > > > > > > > > > > > > > Thats interesting. Does logspace also > > > > > > > > > > return a range? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tuesday, September 29, 2015 at > > > > > > > > > > 5:43:28 PM UTC-7, Chris > > > > > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > In 0.4 the linspace function > > > > > > > > > > returns a range object, > > > > > > > > > > > > > > > > > > and you need to use collect() to > > > > > > > > > > expand it. I'm also > > > > > > > > > > > > > > > > > > interested in nicer syntax. > > > > > > > > > > > > > > > > > > > > > > > > > > >
