From octave-sources-request at bevo dot che dot wisc dot edu Mon Dec 16 09:42:46 2002
Subject: Convolution matrix function(debugged)
From: Anand V <anand dot v at achayans dot com>
To: octave-sources at bevo dot che dot wisc dot edu
Date: Sun, 15 Dec 2002 22:33:39 -0600

Hi,
  I had to modify the function as I found a bug during testing. 
It is because of the toeplitz matrix function call. If the first element,of the row and column are different, then the column will win the diagonal conflict in Toeplitz matrix. I have corrected this and am appending the new code. 
  I have tested it for programs where I needed to generate convolution matrix and operate. It seems to give satisfactory results. 

# Function to get convolution matrix given a vector 'h' and length of x (n)

function retval = convmtx(h,n)

  if (nargin != 2)
    usage ("convmtx(h,n)");
  endif

nr = rows(h);
nc = columns(h);

if ( (nr > 1) && (nc > 1) )
  usage("'h' should be either a row or column vector");

elseif (nc == 1)
h = h.';
endif

r = [h,zeros(1,n-1)];
c = [h(1),zeros(1,n-1)];

if (nr == 1)
retval = toeplitz(c,r);
endif

if (nc == 1)
retval = toeplitz(c,r).';
endif

endfunction

Thanks and Regards 
Anand


_____________________________________________________________
Kerala's coolest community site ---> http://www.achayans.com

India's fastest growing Search Engine ->
http://www.indianindex.com

India's largest Online Matchmakers -->
http://www.indianalliance.com

_____________________________________________________________
Select your own custom email address for FREE! Get you at yourchoice dot com w/No Ads, 6MB, POP & more! http://www.everyone.net/selectmail?campaign=tag