[scilab-Users] Re: speed of Scilab 5.3.2 vs Scilab 5.3.1

[Ginters Bušs]

Then
Scilab 5.3.2. spends about 0.4sec
Scilab 5.3.1. spends about 5 sec
Scilab 4.1.2. spends about 0.15sec

However, the code result is different from the previous one:

n=100000;
sigeps=1;
mi=grand(n,1,'nor',0,sigeps);
for i=2:n;
    mi(i)=mi(i)+mi(i-1);
end

produces a random walk, but

n=100000;
sigeps=1;
mi=grand(n,1,'nor',0,sigeps);
mi(2:n)=mi(2:n)+mi(1:n-1);

does not.

Gin.



On Wed, Jul 20, 2011 at 11:50 AM, Allan CORNET <allan.cornet at scilab.org>wrote:

> Hi,****
>
> ** **
>
> You know that you can remove loop in  your script ?****
>
> ** **
>
> Try:****
>
> ** **
>
> tic()****
>
> sigeta=2; sigeps=1;****
>
> mi=[];****
>
> c=[];****
>
> y=[];****
>
> skait=[];****
>
> sauc2=[];****
>
> rho=[];****
>
> f1=1.2;****
>
> f2=-0.5;****
>
> n=102000;****
>
> k=2000;****
>
> c=grand(n,1,'nor',0,sigeta);****
>
> c(2)=f1*c(1)+c(2);****
>
> mi=grand(n,1,'nor',0,sigeps);****
>
> ** **
>
> c(3:n) = c(3:n)+f1*c(2:n-1)+f2*c(1:n-2);****
>
> ** **
>
> mi(2:n)=mi(2:n)+mi(1:n-1);****
>
> ** **
>
> y=c+mi;****
>
> y(1:k)=[];****
>
> c(1:k)=[];****
>
> i=1:length(y);****
>
> skait=sum((y(i)-mean(y)).*(c(i)-mean(c)));****
>
> sauc2=sum((y(i)-mean(y))^2)*sum((c(i)-mean(c))^2);****
>
> rho=skait/sqrt(sauc2)****
>
> toc()****
>
> ** **
>
> Allan****
>
> ** **
>
> *De :* Ginters Bušs [mailto:ginters.buss at gmail.com]
> *Envoyé :* mercredi 20 juillet 2011 10:35
> *À :* users at lists.scilab.org
> *Objet :* [scilab-Users] Re: speed of Scilab 5.3.2 vs Scilab 5.3.1****
>
> ** **
>
> And about 1.65sec. on Scilab 4.1.2.
>
> So, still Scilab 4 is faster, but only marginally.
>
> ****
>
> On Wed, Jul 20, 2011 at 11:23 AM, Ginters Bušs <ginters.buss at gmail.com>
> wrote:****
>
> Hi,
>
> Just to let you know:
> I just found out that version 5.3.2. runs faster than 5.3.1.
>
> Say, this code:
>
> tic()
> sigeta=2; sigeps=1;
> mi=[]; c=[]; y=[]; skait=[]; sauc2=[]; rho=[];
> f1=1.2; f2=-0.5;
> n=102000; k=2000;
> c=grand(n,1,'nor',0,sigeta);
> c(2)=f1*c(1)+c(2);
> mi=grand(n,1,'nor',0,sigeps);
> for i=3:n;
>     c(i)=c(i)+f1*c(i-1)+f2*c(i-2);
> end
> for i=2:n;
>     mi(i)=mi(i)+mi(i-1);
> end
> y=c+mi;
> y(1:k)=[];
> c(1:k)=[];
> i=1:length(y);
> skait=sum((y(i)-mean(y)).*(c(i)-mean(c)));
> sauc2=sum((y(i)-mean(y))^2)*sum((c(i)-mean(c))^2);
> rho=skait/sqrt(sauc2)
> toc()
>
> takes approx. 1.75sec. (on my PC) on Scilab 5.3.2, while approx. 6 sec. on
> Scilab 5.3.1.
>
> Gin.****
>
> ** **
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.scilab.org/pipermail/users/attachments/20110720/293707c2/attachment.htm>