return on push (and other dequeue functions)... why not push! instead ?

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return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 3:30 PM
push modifies the input Array and returns the modified Array too.
Given the modification on input, why is not push!
return is not redundant?

julia> ie = [1; 2]
2-element Int64 Array:
 
1
 
2

julia
> push(ie,3)
3-element Int64 Array:
 
1
 
2
 
3

julia
> ie
3-element Int64 Array:
 
1
 
2
 
3


Re: return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 4:14 PM
But... append! is with ! and not append.

Maybe can be dequeue functions with a return (and without modify the input) working on immutable too (strings) without ! and other without return with ! in the name for indicate modification of the input Array ?
Re: [julia-dev] Re: return on push (and other dequeue functions)... why not push! instead ? John Myles White 1/5/13 4:22 PM
I think push should be push!. And del should be del!.

 -- John

--
 
 
 

Re: [julia-dev] Re: return on push (and other dequeue functions)... why not push! instead ? Jeffrey Sarnoff 1/5/13 6:34 PM
+1
Re: [julia-dev] Re: return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 6:48 PM
Is return the input Array of this functions necessary ? I look for situation on the Julia code where this ( redundant ? ) returns where used. I found that only in grow and del is used (and except for sparse.jl, the other used of the return value looks redundant -assigned to the new Array to itself- )

dzea@deepthought:~$ grep "=\s*push(" ./bin/julia/base/*.jl

dzea@deepthought:~$ grep "=\s*append\!(" ./bin/julia/base/*.jl
./bin/julia/base/bitarray.jl:append!(B::BitVector, items::AbstractVector{Bool}) = append!(B, bitpack(items))
./bin/julia/base/bitarray.jl:append!(A::Vector{Bool}, items::BitVector) = append!(A, bitunpack(items))

dzea@deepthought:~$ grep "=\s*grow(" ./bin/julia/base/*.jl
./bin/julia/base/linalg_sparse.jl:            rowvalC = grow(rowvalC, max(nnzC,mA))
./bin/julia/base/linalg_sparse.jl:            nzvalC = grow(nzvalC, max(nnzC,mA))

dzea@deepthought:~$ grep "=\s*enqueue(" ./bin/julia/base/*.jl
./bin/julia/base/multi.jl:enq_work(wi::WorkItem) = enqueue(Workqueue, wi)

dzea@deepthought:~$ grep "=\s*unshift(" ./bin/julia/base/*.jl

dzea@deepthought:~$ grep "=\s*insert(" ./bin/julia/base/*.jl

dzea@deepthought:~$ grep "=\s*del(" ./bin/julia/base/*.jl
./bin/julia/base/dict.jl:del{K}(wkh::WeakKeyDict{K}, key) = del(wkh.ht, key)
./bin/julia/base/linalg_sparse.jl:    rowvalC = del(rowvalC, colptrC[end]:length(rowvalC))
./bin/julia/base/linalg_sparse.jl:    nzvalC = del(nzvalC, colptrC[end]:length(nzvalC))
./bin/julia/base/multi.jl:del_fd_handler(fd::Int32) = del(fd_handlers, fd)
./bin/julia/base/sparse.jl:            rowvalS = del(rowvalS, colptrS[end]:length(rowvalS))
./bin/julia/base/sparse.jl:            nzvalCS = del(nzvalS, colptrS[end]:length(nzvalS))
./bin/julia/base/sparse.jl:    A.rowval = del(rowvalS, colptrS[end]:length(rowvalS))
./bin/julia/base/sparse.jl:    A.nzval  = del(nzvalS, colptrS[end]:length(nzvalS))

dzea@deepthought:~$ grep "=\s*del_all(" ./bin/julia/base/*.jl

dzea@deepthought:~$

Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Brian Mattern 1/5/13 6:53 PM
The return allows chaining functions together (e.g., multiple push operations). So, it isn't completely redundant.

Brian

On Jan 5, 2013, at 3:30 PM, Diego Javier Zea <dieg...@gmail.com> wrote:

push modifies the input Array and returns the modified Array too.
...
return is not redundant?
Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 7:04 PM
Thanks Brian, I don't think in chained one inside the other!
...but you can chaining only bay execute one before the other. Don't looks that something that it's going to generate troubles...

julia> a = [ 1; 2; 3; 4; 5; 6 ]

6-element Int64 Array:
 
1
 
2
 
3

 
4
 
5
 
6

julia
> push(push(a,7),8)

8-element Int64 Array:
 
1
 
2
 
3

 
4
 
5
 
6
 
7
 
8

julia
> function push!{T}(a::Array{T,1}, item)
           
if is(T,None)                                    
               error
("[] cannot grow. Instead, initialize the array with \"T[]\".")
           
end
           
# convert first so we don't grow the array if the assignment won't work
           item
= convert(T, item)
           ccall
(:jl_array_grow_end, Void, (Any, Uint), a, 1)
           a
[end] = item
           nothing
       
end

julia
> function push!(a::Array{Any,1}, item::ANY)
           ccall
(:jl_array_grow_end, Void, (Any, Uint), a, 1)
           arrayset
(a, item, length(a))
           nothing
       
end

julia
> push!(push!(a,9),10)
no method push!(Nothing,Int64)

julia
> a
9-element Int64 Array:
 
1
 
2
 
3

 
4
 
5
 
6
 
7
 
8
 
9

julia
> push!(a,10)

julia
> push!(a,11)

julia
> a
11-element Int64 Array:
 
1
 
2
 
3
 
4
 
5
 
6
 
7
 
8
 
9
 
10
 
11

Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 7:06 PM
For example; push inside push is not used on the code of base.

dzea@deepthought:~$ grep "push.*push" ./bin/julia/base/*.jl
./bin/julia/base/git.jl:            run(`git config remote.origin.pushurl $pushurl`)


Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 8:05 PM
Without the return, and with nothing instead looks to be a little more faster too ;)
[ for example, the push! definition without return - on previous messages - its a little more faster than the actual push ]

The mean with return is:   4.70e-5 +- 0.045e-5
And without return:        4.56e-5 +- 0.049e-5



Mean elapsed time N on accumulated elapsed time * 1000 < 120
With return Without return
With return Without return
4.75E-05 4.58E-05 1 2528866 2620081 1
4.64E-05 4.63E-05 1 2585591 2590230 1
4.68E-05 4.39E-05 1 2563664 2732904 1
4.88E-05 4.43E-05 1 2460211 2707355 1
4.73E-05 4.49E-05 1 2537059 2671809 1
4.37E-05 4.38E-05 0 2746197 2737611 0
4.39E-05 4.24E-05 1 2735401 2833182 1
4.90E-05 4.23E-05 1 2448759 2839539 1
4.87E-05 4.94E-05 0 2463836 2427746 0
4.86E-05 4.75E-05 1 2470752 2523721 1
4.87E-05 4.74E-05 1 2466148 2533975 1
4.82E-05 4.75E-05 1 2487281 2524607 1
4.51E-05 4.71E-05 0 2658315 2546760 0
4.57E-05 4.49E-05 1 2624526 2671443 1
4.54E-05 4.55E-05 0 2645352 2634962 0
4.89E-05 4.57E-05 1 2455947 2624691 1


0.75

0.75
Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 8:07 PM
The code of the previous measure (running 2 times, altering the order of execution between one measure and the other):

macro timeit(ex)
    quote
        gc
()
        t_cum
= 0
        i
=1
        t
=Float64[]
       
while t_cum*1000 < 120
            push
(t,@elapsed $ex)
            t_cum
+= t[i]
            i
+= 1
       
end
    t
.*= 1000
    println
("Mean\tSD\tN\tMin:\t$(Base.mean(t))\t$(Base.std(t))\t$(i-1)\t$(Base.min(t))")
   
end
end
a
=[1;2]
push
([1;2],3)
a
a
=[1;2]
push
!([1;2],3)
a
for i in 1:2
 println
("---------------------------------------------------")
 a
=[1:100]
 
print("without return:\t")
 
@timeit push!(a,1)
 a
=[1:100]
 
print("with return:\t")
 
@timeit push(a,1)  
 a
=[1:100]
 
print("without return:\t")
 
@timeit push!(a,1)  
 a
=[1:100]
 
print("with return:\t")
 
@timeit push(a,1)
 a
=[1:100]
 
print("without return:\t")
 
@timeit push!(a,1)
 a
=[1:100]
 
print("with return:\t")
 
@timeit push(a,1)  
 a
=[1:100]
 
print("without return:\t")
 
@timeit push!(a,1)  
 
print("with return:\t")
 
@timeit push(a,1)
end

...
Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/5/13 10:51 PM
But... Even if the (redundant) return statement is maintained in this dequeue functions, the names must have a ! for follow the rule:

The last function, fill!, is different in that it modifies an existing array instead of constructing a new one. As a convention, functions with this property have names ending with an exclamation point. These functions are sometimes called “mutating” functions, or “in-place” functions.

 
9

julia
> push!(a,10)

julia
> push!(a,11)

julia
> a
11-element Int64 Array:

 
1
 
2
 
3
 
4
 
5
 
6
 
7
 
8

 
9
 
10
 
11






El sábado, 5 de enero de 2013 23:53:02 UTC-3, Brian Mattern escribió:
The return allows chaining functions together (e.g., multiple push operations). So, it isn't completely redundant.

Brian

On Jan 5, 2013, at 3:30 PM, Diego Javier Zea <dieg...@gmail.com> wrote:

push modifies the input Array and returns the modified Array too.
...
return is not redundant?
Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Diego Javier Zea 1/6/13 3:28 PM

I do a very simple test for push against push! in this mail list [ previous link ] yesterday at 3 AM. Excuse me... it's wrong [ it's lees than a 1% better, probably only measurement error ]. Here a test for:

function enqueue!{T}(a::Array{T,1}, item)
    if is(T,None)
        error("[] cannot grow. Instead, initialize the array with \"T[]\".")
    end
    item = convert(T, item)
    ccall(:jl_array_grow_beg, Void, (Any, Uint), a, 1)
    a[1] = item
    nothing
end

And the results are:

        BenchmarkCategory BenchmarkName Iterations Fun_wins_to_Fun2 Fun2_wins_to_Fun    Ties  TotalWall AverageWall    MaxWall MinWall             Timestamp            JuliaVersion    JuliaHash CodeHash      OS
[1,]     "compare_return"        "with"      50220          4.60024          4.78505 90.6147 0.00282693  5.62909e-8   9.799e-5     0.0 "2013-01-06 19:51:44" "0.0.0+106484954.r5387" "53872cd2c9"       NA "Linux"
[2,]     "compare_return"     "without"      49780          4.60024          4.78505 90.6147 0.00268102  5.38573e-8 5.38826e-5     0.0 "2013-01-06 19:51:44" "0.0.0+106484954.r5387" "53872cd2c9"       NA "Linux"

But, I still think that the names need to be ending in ! for indicate modification of input data.

Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? John Myles White 1/6/13 4:18 PM
I still support renaming push to push!.

I think allowing a return value from push is very important.

 -- John

--
 
 
 

Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Stefan Karpinski 1/7/13 7:23 AM
Ok, I think there's pretty strong consensus that these mutating operations in Base should be renamed to have ! at their ends, so I'm resolving to make that change this week, giving people some warning before switching.


--
 
 
 

Re: [julia-dev] return on push (and other dequeue functions)... why not push! instead ? Milktrader 1/7/13 7:30 AM
+1 (I thought this was already the Julian way)