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comparison scripts/finance/pv.m @ 3426:f8dde1807dee

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[project @ 2000-01-13 08:40:00 by jwe]
author jwe
date Thu, 13 Jan 2000 08:40:53 +0000
parents ae7adbb591e8
children 3234a698073a
comparison
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3425:8625164a0a39 3426:f8dde1807dee
1 ## Copyright (C) 1995, 1996 Kurt Hornik 1 ## Copyright (C) 1995, 1996 Kurt Hornik
2 ## 2 ##
3 ## This program is free software; you can redistribute it and/or modify 3 ## This program is free software; you can redistribute it and/or modify
4 ## it under the terms of the GNU General Public License as published by 4 ## it under the terms of the GNU General Public License as published by
5 ## the Free Software Foundation; either version 2, or (at your option) 5 ## the Free Software Foundation; either version 2, or (at your option)
6 ## any later version. 6 ## any later version.
7 ## 7 ##
8 ## This program is distributed in the hope that it will be useful, but 8 ## This program is distributed in the hope that it will be useful, but
9 ## WITHOUT ANY WARRANTY; without even the implied warranty of 9 ## WITHOUT ANY WARRANTY; without even the implied warranty of
10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 ## General Public License for more details. 11 ## General Public License for more details.
12 ## 12 ##
13 ## You should have received a copy of the GNU General Public License 13 ## You should have received a copy of the GNU General Public License
14 ## along with this file. If not, write to the Free Software Foundation, 14 ## along with this file. If not, write to the Free Software Foundation,
15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
16 16
17 ## -*- texinfo -*- 17 ## -*- texinfo -*-
28 ## 28 ##
29 ## Note that the rate r is not specified in percent, i.e., one has to 29 ## Note that the rate r is not specified in percent, i.e., one has to
30 ## write 0.05 rather than 5 %. 30 ## write 0.05 rather than 5 %.
31 ## @end deftypefn 31 ## @end deftypefn
32 ## @seealso{pmt, nper, rate, and npv} 32 ## @seealso{pmt, nper, rate, and npv}
33 33
34 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> 34 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
35 ## Description: Present value of an investment 35 ## Description: Present value of an investment
36 36
37 function v = pv (r, n, p, l, m) 37 function v = pv (r, n, p, l, m)
38 38
39 if ((nargin < 3) || (nargin > 5)) 39 if ((nargin < 3) || (nargin > 5))
40 usage ("pv (r, n, p [, l] [, method])"); 40 usage ("pv (r, n, p [, l] [, method])");
41 endif 41 endif
42 42
43 if !(is_scalar (r) && (r > -1)) 43 if !(is_scalar (r) && (r > -1))
44 error ("pv: r must be a scalar > -1"); 44 error ("pv: r must be a scalar > -1");
45 elseif !(is_scalar (n) && (n > 0)) 45 elseif !(is_scalar (n) && (n > 0))
46 error ("pv: n must be a positive scalar"); 46 error ("pv: n must be a positive scalar");
47 elseif !is_scalar (p) 47 elseif !is_scalar (p)
48 error ("pv: p must be a scalar."); 48 error ("pv: p must be a scalar.");
49 endif 49 endif
50 50
51 if (r != 0) 51 if (r != 0)
52 v = p * (1 - (1 + r)^(-n)) / r; 52 v = p * (1 - (1 + r)^(-n)) / r;
53 else 53 else
54 v = p * n; 54 v = p * n;
55 endif 55 endif
56 56
57 if (nargin > 3) 57 if (nargin > 3)
58 if (nargin == 5) 58 if (nargin == 5)
59 if !isstr (m) 59 if !isstr (m)
60 error ("pv: `method' must be a string"); 60 error ("pv: `method' must be a string");
61 endif 61 endif
62 elseif isstr (l) 62 elseif isstr (l)
63 m = l; 63 m = l;
64 l = 0; 64 l = 0;
65 else 65 else
72 v = v + pvl (r, n, l); 72 v = v + pvl (r, n, l);
73 else 73 else
74 error ("pv: l must be a scalar"); 74 error ("pv: l must be a scalar");
75 endif 75 endif
76 endif 76 endif
77 77
78 endfunction 78 endfunction
79 79