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1 ### Copyright (C) 1996 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 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 ## usage: beta (a, b) |
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21 ## |
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22 ## Returns the beta function beta(a,b) = gamma(a) * gamma(b) / gamma(a+b) |
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23 ## of a and b. |
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24 |
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25 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> |
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26 ## Created: 13 June 1993 |
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27 ## Adapted-By: jwe |
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28 |
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29 function retval = beta (a, b) |
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30 |
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31 if (nargin != 2) |
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32 usage ("beta (a, b)"); |
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33 endif |
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34 |
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35 retval = exp (lgamma (a) + lgamma (b) - lgamma (a+b)); |
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36 |
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37 endfunction |
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38 |
