[Scilab-users] For loop - maximum size

[Tingsten]

Hello everybody,

I assume this kind of talk about the effectiveness of the For loop in Scilab
has been discussed many times but I was not able to find a recent topic
about it....

I am usually post-processing big csv files and by reading them I noticed
some important time change depending of the architecture of the loop.

So i did some very quick and simple tests with the following results :

1)timer();A=[];for i=1:100000,A=[A;i];,end;timer()
 ans  =
     16.598506

2)timer();B=[];for j=1:10,A=[];for
i=1:10000,A=[A;i];,end;B=[B;A];,end;timer()
 ans  =
     1.0452067 

3)timer();B=[];for j=1:100,A=[];for
i=1:1000,A=[A;i];,end;B=[B;A];,end;timer()
 ans  =
     0.4992032 

4)timer();B=[];for j=1:1000,A=[];for
i=1:100,A=[A;i];,end;B=[B;A];,end;timer()
 ans  =
     0.9204059 

5)timer();C=[];for h=1:10,B=[];for j=1:100,A=[];for
i=1:100,A=[A;i];,end;B=[B;A];,end,C=[C;B];,end;timer()
 ans  =
     0.4524029   

It is probably explainable but interesting to know that 3) is 30 time better
than 1).
So I would think that it is totally forbidden to be efficient to do loop
>10000.
Any comment or advice about that?

Thx you a lot,
Rémi Mercier



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