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1 ## Copyright (C) 1998 Auburn University. All rights reserved. |
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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 2, or (at your option) |
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8 ## 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, write to the Free |
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17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
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18 ## 02111-1307, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} qtransvmat (@var{qib}) |
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22 ## Construct a 3x3 transformation matrix from quaternion @var{qib} that |
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23 ## is equivalent to rotation of th radians about axis @var{vv}, where |
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24 ## @code{[@var{vv}, @var{th}] = quaternion (@var{qib})}. |
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25 ## @end deftypefn |
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26 |
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27 ## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu> |
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28 ## Adapted-By: jwe |
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29 |
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30 function Aib = qtransvmat (qib) |
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31 |
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32 if (! isvector(qib) || length (qib) != 4) |
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33 error ("qtransvmat: q(%d,%d) must be a quaternion", rows (qib), \ |
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34 columns (qib)); |
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35 elseif (max (abs (imag (qib))) != 0) |
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36 error ("qtransvmat: input values must be real"); |
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37 endif |
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38 |
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39 Aib = [(2.*(qib(1)^2 + qib(4)^2) -1.), |
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40 (2.*(qib(1)*qib(2)-qib(3)*qib(4))), |
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41 (2.*(qib(1)*qib(3)+qib(2)*qib(4))); |
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42 (2.*(qib(1)*qib(2)+qib(3)*qib(4))), |
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43 (2.*(qib(2)*qib(2)+qib(4)*qib(4))-1.), |
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44 (2.*(qib(2)*qib(3)-qib(1)*qib(4))); |
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45 (2.*(qib(1)*qib(3)-qib(2)*qib(4))), |
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46 (2.*(qib(2)*qib(3)+qib(1)*qib(4))), |
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47 (2.*(qib(3)*qib(3)+qib(4)*qib(4))-1.)]; |
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48 |
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49 endfunction |
