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comparison scripts/polynomial/polyfit.m @ 2303:5cffc4b8de57

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[project @ 1996-06-24 09:15:24 by jwe]
author jwe
date Mon, 24 Jun 1996 09:15:24 +0000
parents 1b6e1629fb91
children 2b5788792cad
comparison
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2302:470c856bf55a 2303:5cffc4b8de57
1 ### Copyright (C) 1996 John W. Eaton
2 ###
3 ### This file is part of Octave.
4 ###
5 ### Octave is free software; you can redistribute it and/or modify it
6 ### under the terms of the GNU General Public License as published by
7 ### the Free Software Foundation; either version 2, or (at your option)
8 ### any later version.
9 ###
10 ### Octave is distributed in the hope that it will be useful, but
11 ### WITHOUT ANY WARRANTY; without even the implied warranty of
12 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ### General Public License for more details.
14 ###
15 ### You should have received a copy of the GNU General Public License
16 ### along with Octave; see the file COPYING. If not, write to the Free
17 ### Software Foundation, 59 Temple Place - Suite 330, Boston, MA
18 ### 02111-1307, USA.
19
1 function p = polyfit (x, y, n) 20 function p = polyfit (x, y, n)
2 21
3 # usage: polyfit (x, y, n) 22 ## usage: polyfit (x, y, n)
4 # 23 ##
5 # Returns the coefficients of a polynomial p(x) of degree n that 24 ## Returns the coefficients of a polynomial p(x) of degree n that
6 # minimizes sumsq (p(x(i)) - y(i)), i.e., that best fits the data 25 ## minimizes sumsq (p(x(i)) - y(i)), i.e., that best fits the data
7 # in the least squares sense. 26 ## in the least squares sense.
8 27
9 # Written by KH (Kurt.Hornik@ci.tuwien.ac.at) on Dec 13, 1994 28 ## Written by KH (Kurt.Hornik@ci.tuwien.ac.at) on Dec 13, 1994
10 # Copyright Dept of Statistics and Probability Theory TU Wien 29 ## Copyright Dept of Statistics and Probability Theory TU Wien
11 30
12 if (nargin != 3) 31 if (nargin != 3)
13 usage ("polyfit (x, y, n)"); 32 usage ("polyfit (x, y, n)");
14 endif 33 endif
15 34
30 if (n > 0) 49 if (n > 0)
31 tmp = (x * ones (1, n)) .^ (ones (l, 1) * (1 : n)); 50 tmp = (x * ones (1, n)) .^ (ones (l, 1) * (1 : n));
32 X = [X, tmp]; 51 X = [X, tmp];
33 endif 52 endif
34 53
35 # Compute polynomial coeffients, making returned value compatible 54 ## Compute polynomial coeffients, making returned value compatible
36 # with Matlab. 55 ## with Matlab.
37 56
38 [Q, R] = qr (X, 0); 57 [Q, R] = qr (X, 0);
39 58
40 p = flipud (R \ (Q' * y)); 59 p = flipud (R \ (Q' * y));
41 60