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1 # Copyright (C) 1993 John W. Eaton |
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2 # |
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3 # This file is part of Octave. |
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4 # |
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5 # Octave is free software; you can redistribute it and/or modify it |
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6 # under the terms of the GNU General Public License as published by the |
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7 # Free Software Foundation; either version 2, or (at your option) any |
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8 # later version. |
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9 # |
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10 # Octave is distributed in the hope that it will be useful, but WITHOUT |
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11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 # FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 # for more details. |
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14 # |
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15 # You should have received a copy of the GNU General Public License |
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16 # along with Octave; see the file COPYING. If not, write to the Free |
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17 # Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
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18 |
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4
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19 function retval = vander (c) |
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20 |
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21 # usage: vander (c) |
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22 # |
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23 # Return the Vandermonde matrix whose next to last column is c. |
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24 # |
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25 # See also: hankel, hadamard, hilb, invhilb, toeplitz |
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26 |
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27 if (nargin != 1) |
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28 error ("usage: vander (c)"); |
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29 endif |
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30 |
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31 nr = rows (c); |
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32 nc = columns (c); |
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33 if (nr == 1 && nc == 1) |
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34 retval = 1; |
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35 elseif (nr == 1 || nc == 1) |
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36 n = length (c); |
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37 if (n > 0) |
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38 retval = zeros (n, n); |
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39 for i = 1:n |
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40 tmp = c(i); |
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41 for j = 1:n |
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42 retval (i, j) = tmp ^ (n - j); |
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43 endfor |
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44 endfor |
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45 endif |
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46 else |
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47 error ("vander: argument must be a vector"); |
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48 endif |
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49 |
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50 endfunction |
