> In my code, there are such arrays (with BigFloat instead of character
> string) :
>
> julia> ARRAY = ["a", "b", "c"]
>
> 3-element Array{ASCIIString,1}:
>
> "a"
>
> "b"
>
> "c"
>
>
> and I perform this operation :
>
> julia> SHIFTED_ARRAY = ARRAY[[2:length(ARRAY); 1]]
>
> 3-element Array{ASCIIString,1}:
>
> "b"
>
> "c"
>
> "a"
>
>
> in order to apply a certain function *F(ARRAY, SHIFTED_ARRAY)*.
So, my suggestion would translate into defining a
F(ARRAY, SHIFT)
which will then run its loop with the shift applied. Instead of making
a shifted array.
say something like
function F(ARRAY, SHIFT)
acc = 0
for (i,A) in enumerate(ARRAY)
acc += A[i] + A[rem1(i+SHIFT, length(ARRAY))]
end
return acc
end
> Analogously, in the Linux system you can create *"symbolic links"* to a
> file, which is somewhat a copy of the file but not taking some space on the
> hard drive. Again, I don't know how a programming language works, but is
> there something analogous to a *"symbolic link to a variable"*, imrproving
> some performance as compared to a "true" copy ?
That is what ArrayViews does:
>> If that is not what you need you could look into ArrayViews:
>> https://github.com/lindahua/ArrayViews.jl
>> https://github.com/JuliaLang/julia/pull/5556
> Le lundi 9 juin 2014 20:12:21 UTC+2, Mauro a écrit :
>>
>> This smells of vectorization. If so, in Julia, you should try to change
>> your loops rather than change your arrays. Maybe like so:
>>
>> julia> a = [1:5];
>>
>> julia> la = length(a);
>>
>> julia> off = 0;
>>
>> julia> for i=1+off:la+off
>> println(a[rem1(i,la)])
>> end
>> 1
>> 2
>> 3
>> 4
>> 5
>>
>> julia> off = 1;
>>
>> julia> for i=1+off:la+off
>> println(a[rem1(i,la)])
>> end
>> 2
>> 3
>> 4
>> 5
>> 1
>>
>> If that is not what you need you could look into ArrayViews:
>> https://github.com/lindahua/ArrayViews.jl
>> https://github.com/JuliaLang/julia/pull/5556
>>
>> On Mon, 2014-06-09 at 18:37, julia...@googlegroups.com <javascript:>
>> wrote:
>> > Hi,
>> >
>> > In a program I have some *n*1* arrays, say
>> >
>> > *A*
>> > *B*
>> > *C*
>> > *D*
>> >
>> >
>> > and in order to make a certain calculation, for convenience, I construct
>> > the array
>> >
>> > *A B*
>> > *B C*
>> > *C D*
>> > *D A*
>> >
>> >
>> > There will be millions of such arrays generated by my final program,
>> with
>> > *n* greater than 4 and the components A, B, C, D, ... are *BigFloat*.
>> >
>> > Then I'm wondering how to optimize my copy from the first array to the
>> > second array. Is there something to gain performance when we duplicate
>> some
>> > variables ?
>>
>>
