Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / financial-0.4.0 / pvl.m

diff --git a/octave_packages/financial-0.4.0/pvl.m b/octave_packages/financial-0.4.0/pvl.m
new file mode 100644 (file)
index 0000000..d6dbcb0
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+++ b/octave_packages/financial-0.4.0/pvl.m
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+## Copyright (C) 1995-1998, 2000, 2002, 2005-2007 Kurt Hornik <Kurt.Hornik@wu-wien.ac.at>
+##
+## 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 3 of the License, 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 program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{v} =} pvl (@var{r}, @var{n}, @var{p})
+## Return the present value @var{v} of an investment that will pay off @var{p}
+## in one lump sum at the end of @var{n} periods, given the interest
+## rate @var{r}.
+##
+## Note that the rate @var{r} is specified as a fraction (i.e., 0.05,
+## not 5 percent).
+## @end deftypefn
+
+function v = pvl (r, n, p)
+
+  if (nargin != 3)
+    print_usage ();
+  endif
+
+  if (! (isscalar (r) && (r > -1)))
+    error ("pvl: r has to be a scalar > -1");
+  elseif (! (isscalar (n) && n > 0))
+    error ("pvl: n has to be a positive scalar");
+  elseif (! isscalar (p))
+    error ("pvl: p has to be a scalar");
+  endif
+
+  v = p / (1 + r)^n;
+
+endfunction