Re: Puncher soft limiter !!!

[Paul Kienzle]

cctsim wrote:

> On Wednesday 04 Jun 2003 12:37 pm, Paul Kienzle wrote:
>
>  
>
> > Try max([-5:0.1:5]).  You may find
> > that it is 4.9.  Or it may be that it is
> > a tiny bit above 5 due to cumulative
> > rounding error when adding 0.1.
> >
> > Next try max(linspace(-5,5,101)), and
> > see if that is any better.
> >    
>
> I tried the following:
>  
>
> > > format long
> > > max([-5:0.1:5])
> > >      
> ans = 5.00000000000000
try:  max([-5:0.1:5])-5

> The only the thing that seems to work is:
>
>  
>
> > > max(puncher(linspace(-5,5,101),5))
> > >      
> ans = 5
>
> but now I am not sure if this 100% unconditional !
For that, you will have to use the source (liboctave/dRowVector.cc):

   double delta = (x2-x1)/(n-1);
   x(0) = x1;
   for (i=0; i < n-1; i++) x(i) = x1+i*delta;
   x(n-1) = x2;

So the answer is definitely yes.

> > You should find the perfomance of
> >    x(x<-A | x>A) = 0;
> > acceptable unless your arrays are
> > really large in which case you will
> > run into other problems. No need
> > for C++ here.
> >    
>
> x(x<-A | x>A) = 0; 
> This is cool !!! But still suffers from the same problem.
> Is there any way not to overwrite x without using dummy variables ?
y = x(x>=-A & x <= A);

> I know C++ seems a bit overkill for the puncher but my plan 
> was to use it as a template for the Hampel soft limiter for
> complex signals which is computationally more complicated.
> I have it running using a conventional m-function but is very slow.
For loops in octave are slow.  If you can
express your algorithm with vector or
matrix operations, then the overhead of
octave is not a problem.

Paul Kienzle
address@hidden




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