Mercurial > octave
view scripts/special-matrix/hankel.m @ 4:b4df021f796c
[project @ 1993-08-08 01:26:08 by jwe]
Initial revision
author | jwe |
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date | Sun, 08 Aug 1993 01:26:08 +0000 |
parents | |
children | 16a24e76d6e0 |
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function retval = hankel (c, r) # usage: hankel (c, r) # # Return the Hankel matrix constructed given the first column # c, and (optionally) the last row r. # # If the second argument is omitted, the last row is taken to be the # same as the first column. If the last element of c is not the same # as the first element of r, the last element of c is used. # # See also: vander, hadamard, hilb, invhilb, toeplitz if (nargin == 1) r = c; elseif (nargin != 2) error ("usage: hankel (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 ("hankel: expecting vector arguments") endif if (c_nc != 1) c = c'; endif if (r_nr != 1) r = r'; endif if (r (1) != c (1)) disp ("Column wins anti-diagonal conflict"); endif # This should probably be done with the colon operator... nc = length (r); nr = length (c); retval = zeros (nr, nc); for i = 1:min (nr, nc) retval (1:nr-i+1, i) = c (i:nr); endfor tmp = 1; if (nc <= nr) tmp = nr - nc + 2; endif for i = nr:-1:tmp retval (i, 2+nr-i:nc) = r (2:nc-nr+i); endfor endfunction