Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/financial-0.4.0/taxedrr.m b/octave_packages/financial-0.4.0/taxedrr.m
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+## Copyright (C) 2008 Bill Denney <bill@denney.ws>
+##
+## 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{return} =} taxedrr (@var{pretaxreturn}, @var{taxrate})
+## Compute the taxed rate of @var{return} based on a @var{pretaxreturn}
+## rate and a @var{taxrate}.
+## @seealso{irr, effrr, nomrr, pvvar, xirr}
+## @end deftypefn
+
+function rate = taxedrr (pretax, taxrate)
+
+  if (nargin != 2)
+    print_usage ();
+  elseif (taxrate < 0 || taxrate > 1)
+    error ("taxedrr: taxrate must be between 0 and 1")
+  endif
+
+  rate = pretax.*(1-taxrate);
+
+endfunction
+
+## Tests
+%!assert (taxedrr (0.12, 0.30), 0.084, 10*eps)
+%!assert (taxedrr (0.12, 0), 0.12, 10*eps)
+%!assert (taxedrr (0.12, 1), 0, 10*eps)