Jessica
Posts:
147
Registered:
3/7/08
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Re: matlab version and "for" loops
Posted:
Jan 22, 2013 4:55 AM
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"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <kdkkd3$hvs$1@newscl01ah.mathworks.com>...
> "Jessica" wrote in message <kdki7n$b6g$1@newscl01ah.mathworks.com>...
> > "Jan Simon" wrote in message <kdj1jg$i5i$1@newscl01ah.mathworks.com>...
> > > Dear Jessica,
> > >
> > > Yes, "newer" versions of Matlab interpret loops much faster using the JIT acceleration. Please note that this means "newer" than version 6.1 from June 2001.
> > >
> > > To check the difference type:
> > >
> > > feature('accel', 'off')
> > > feature('jit', 'off')
> > >
> > > and run your program again.
> > >
> > > If you want to accelerate your code, post it here to get our ideas.
> > >
> > > Kind regards, Jan
> >
> > Thanks for this information. My problem is in running this code:
> >
> > %Delete saccades except when they mark the start/stop of image
> > DataLength=size(Sdata);DataLength=DataLength(1);
> > for i=0:DataLength-1
> > if strcmp(GazeType(DataLength-i,1),'Saccade')==1|strcmp(GazeType(DataLength- i,1),'Unclassified')==1;
> > if strcmp(PictureStartColumn2(DataLength-i),'ImageStart')==0
> > if strcmp(PictureStartColumn2(DataLength-i),'ImageEnd')==0;
> > Stextdata2(DataLength-i,:)=[];
> > Sdata(DataLength-i,:)=[];
> > end;
> > end;
> > end;
> > end;
> > end;
> >
>
> First, it's not for-loop that is slow. Thing that is slow is calling strcmp many times.
> strcmp can work on cell of strings. You should use strcmp and logical indexing to remove unwanted data. No need for-loop at all.
>
> Bruno
Thanks for looking my code over. Do you mind giving me a little more guidance on how I would make a logical index for this particular problem?
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