This is toeplitz.m in view mode; [Download] [Up]
## Copyright (C) 1996 John W. Eaton
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2, or (at your option)
## any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, write to the Free
## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.
## usage: toeplitz (c, r)
##
## Return the Toeplitz matrix constructed given the first column
## c, and (optionally) the first row r.
##
## If the second argument is omitted, the first row is taken to be the
## same as the first column. If the first element of c is not the same
## as the first element of r, the first element of c is used.
##
## See also: hankel, vander, sylvester_matrix, hilb, invhib
## Author: jwe
function retval = toeplitz (c, r)
if (nargin == 1)
r = c;
elseif (nargin != 2)
usage ("toeplitz (c, r)");
endif
[c_nr, c_nc] = size (c);
[r_nr, r_nc] = size (r);
if ((c_nr != 1 && c_nc != 1) || (r_nr != 1 && r_nc != 1))
error ("toeplitz: expecting vector arguments");
endif
if (c_nc != 1)
c = c.';
endif
if (r_nr != 1)
r = r.';
endif
if (r (1) != c (1))
warning ("toeplitz: column wins diagonal conflict");
endif
## If we have a single complex argument, we want to return a
## Hermitian-symmetric matrix (actually, this will really only be
## Hermitian-symmetric if the first element of the vector is real).
if (nargin == 1)
c = conj (c);
c(1) = conj (c(1));
endif
## This should probably be done with the colon operator...
nc = length (r);
nr = length (c);
retval = zeros (nr, nc);
for i = 1:min (nc, nr)
retval (i:nr, i) = c (1:nr-i+1);
endfor
for i = 1:min (nr, nc-1)
retval (i, i+1:nc) = r (2:nc-i+1);
endfor
endfunction
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.