Mercurial > octave-nkf
view scripts/finance/rate.m @ 3426:f8dde1807dee
[project @ 2000-01-13 08:40:00 by jwe]
author | jwe |
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date | Thu, 13 Jan 2000 08:40:53 +0000 |
parents | ae7adbb591e8 |
children | 3234a698073a |
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## Copyright (C) 1995, 1996, 1997 Kurt Hornik ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 2, or (at your option) ## any later version. ## ## This program is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this file. If not, write to the Free Software Foundation, ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} rate (@var{n}, @var{p}, @var{v} [, @var{l}] [,@var{method}]) ## Computes the rate of return on an investment of present value @var{v} which ## pays @var{p} in @var{n} consecutive periods. ## ## With the optional scalar argument @var{l}, one can specify an additional ## lump-sum payment made at the end of @var{n} periods. With the optional ## string argument @var{`method'}, one can specify whether payments are made ## at the end ("e", default) or at the beginning ("b") of each period. ## @end deftypefn ## @seealso{pv, pmt, nper, and npv} ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: Rate of return of an investment function r = rate (n, p, v, l, m) if ((nargin < 3) || (nargin > 5)) usage ("rate (n, p, v [, l] [, method])"); endif if !(is_scalar (n) && (n > 0)) error ("rate: n must be a positive scalar"); elseif !is_scalar (p) error ("rate: p must be a scalar"); elseif !is_scalar (v) error ("rate: p must be a scalar"); endif if (nargin == 5) if !isstr (m) error ("rate: `method' must be a string"); endif elseif (nargin == 4) if isstr (l) m = l; l = 0; else m = "e"; endif else l = 0; m = "e"; endif if !is_scalar (l) error ("rate: l must be a scalar"); endif string = ["function delta = f (r) ", ... "delta = pv (r, %g, %g, %g, \"%s\") - %g; end"]; eval (sprintf (string, n, p, l, m, v)); [r, info] = fsolve ("f", 0); endfunction