Mercurial > octave
view scripts/special-matrix/vander.m @ 3407:5e0a0b1cba43
[project @ 2000-01-06 03:13:55 by jwe]
author | jwe |
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date | Thu, 06 Jan 2000 03:14:17 +0000 |
parents | f37ca3017116 |
children | ae7adbb591e8 |
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## Copyright (C) 1996, 1997 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. ## -*- texinfo -*- ## @deftypefn {Function File} {} vander (@var{c}) ## Return the Vandermonde matrix whose next to last column is @var{c}. ## ## A Vandermonde matrix has the form ## @iftex ## @tex ## $$ ## \left[\matrix{c_0^n & \ldots & c_0^2 & c_0 & 1\cr ## c_1^n & \ldots & c_1^2 & c_1 & 1\cr ## \vdots & & \vdots & \vdots & \vdots\cr ## c_n^n & \ldots & c_n^2 & c_n & 1}\right]. ## $$ ## @end tex ## @end iftex ## @ifinfo ## ## @example ## @group ## c(0)^n ... c(0)^2 c(0) 1 ## c(1)^n ... c(1)^2 c(1) 1 ## . . . . ## . . . . ## . . . . ## ## c(n)^n ... c(n)^2 c(n) 1 ## @end group ## @end example ## @end ifinfo ## @end deftypefn ## @seealso{hankel, sylvester_matrix, hilb, invhilb, toeplitz} ## Author: jwe function retval = vander (c) if (nargin != 1) usage ("vander (c)"); endif nr = rows (c); nc = columns (c); if (nr == 1 && nc == 1) retval = 1; elseif (nr == 1 || nc == 1) n = length (c); if (n > 0) retval = zeros (n, n); for i = 1:n tmp = c(i); for j = 1:n retval (i, j) = tmp ^ (n - j); endfor endfor endif else error ("vander: argument must be a vector"); endif endfunction