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1 ## Copyright (C) 1996, 1997 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 |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {} sylvester_matrix (@var{k}) |
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21 ## Return the Sylvester matrix of order |
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22 ## @iftex |
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23 ## @tex |
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24 ## $n = 2^k$. |
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25 ## @end tex |
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26 ## @end iftex |
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27 ## @ifinfo |
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28 ## n = 2^k. |
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29 ## @end ifinfo |
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30 ## @seealso{hankel, vander, hilb, invhilb, toeplitz} |
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31 ## @end deftypefn |
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32 |
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33 ## Author: jwe |
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34 |
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35 function retval = sylvester_matrix (k) |
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36 |
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37 if (nargin != 1) |
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38 print_usage (); |
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39 endif |
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40 |
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41 if (isscalar (k)) |
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42 if (k < 1) |
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43 retval = 1; |
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44 else |
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45 tmp = sylvester_matrix (k-1); |
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46 retval = [tmp, tmp; tmp, -tmp]; |
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47 endif |
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48 else |
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49 error ("sylvester_matrix: expecting scalar argument"); |
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50 endif |
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51 |
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52 endfunction |
