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annotate scripts/linear-algebra/dmult.m @ 5428:2a16423e4aa0

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[project @ 2005-08-23 18:38:27 by jwe]
author jwe
date Tue, 23 Aug 2005 18:38:28 +0000
parents 4c8a2e4e0717
children 34f96dd5441b
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1 ## Copyright (C) 1995, 1996, 1997 Kurt Hornik
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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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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18 ## 02110-1301, USA.
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19
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20 ## -*- texinfo -*-
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21 ## @deftypefn {Function File} {} dmult (@var{a}, @var{b})
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22 ## If @var{a} is a vector of length @code{rows (@var{b})}, return
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23 ## @code{diag (@var{a}) * @var{b}} (but computed much more efficiently).
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24 ## @end deftypefn
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25
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26 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
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27 ## Description: Rescale the rows of a matrix
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28
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29 function M = dmult (a, B)
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30
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31 if (nargin != 2)
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32 usage ("dmult (a, B)");
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33 endif
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34 if (! isvector (a))
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35 error ("dmult: a must be a vector of length rows (B)");
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36 endif
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37 a = a(:);
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38 sb = size (B);
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39 sb(1) = 1;
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40 M = repmat (a(:), sb) .* B;
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41 endfunction