annotate scripts/linear-algebra/dmult.m @ 3458:d25bc039237b

[project @ 2000-01-19 09:36:14 by jwe]
author jwe
date Wed, 19 Jan 2000 09:36:28 +0000
parents 858695b3ed62
children 38c61cbf086c
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1 ## Copyright (C) 1995, 1996, 1997 Kurt Hornik
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2 ##
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3 ## This program is free software; you can redistribute it and/or modify
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4 ## it under the terms of the GNU General Public License as published by
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5 ## the Free Software Foundation; either version 2, or (at your option)
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6 ## any later version.
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7 ##
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8 ## This program is distributed in the hope that it will be useful, but
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9 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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11 ## General Public License for more details.
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12 ##
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13 ## You should have received a copy of the GNU General Public License
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14 ## along with this file. If not, write to the Free Software Foundation,
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15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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16
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17 ## -*- texinfo -*-
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18 ## @deftypefn {Function File} {} dmult (@var{a}, @var{b})
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19 ## If @var{a} is a vector of length @code{rows (@var{b})}, return
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20 ## @code{diag (@var{a}) * @var{b}} (but computed much more efficiently).
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21 ## @end deftypefn
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23 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
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24 ## Description: Rescale the rows of a matrix
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25
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26 function M = dmult (a, B)
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27
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28 if (nargin != 2)
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29 usage ("dmult (a, B)");
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30 endif
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31
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32 s = size (a);
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33 if ((min (s) > 1) || (max (s) != rows (B)))
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34 error ("dmult: a must be a vector of length rows (B)");
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35 endif
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37 M = (reshape (a, max (s), 1) * ones (1, columns (B))) .* B;
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38
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39 endfunction