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annotate scripts/linear-algebra/dmult.m @ 3408:ae7adbb591e8

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[project @ 2000-01-06 08:29:11 by jwe]
author jwe
date Thu, 06 Jan 2000 08:29:26 +0000
parents e4f4b2d26ee9
children f8dde1807dee
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e4f4b2d26ee9 [project @ 1998-10-23 05:43:59 by jwe]
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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 ## usage: dmult (a, B)
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18 ##
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19 ## If a is a vector of length rows (B), return diag (a) * B (but
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20 ## computed much more efficiently).
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21
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22 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
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23 ## Description: Rescale the rows of a matrix
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24
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25 function M = dmult (a, B)
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26
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27 if (nargin != 2)
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28 usage ("dmult (a, B)");
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29 endif
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30
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31 s = size (a);
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32 if ((min (s) > 1) || (max (s) != rows (B)))
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33 error ("dmult: a must be a vector of length rows (B)");
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34 endif
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35
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36 M = (reshape (a, max (s), 1) * ones (1, columns (B))) .* B;
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37
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38 endfunction