Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / general-1.3.1 / ztvals.m

diff --git a/octave_packages/general-1.3.1/ztvals.m b/octave_packages/general-1.3.1/ztvals.m
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+## Copyright (C) 2009 Jaroslav Hajek <highegg@gmail.com>
+##
+## 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} {} function ztvals (@var{x}, @var{tol})
+## Replaces tiny elements of the vector @var{x} by zeros.
+## Equivalent to 
+## @example
+##   @var{x}(abs(@var{x}) < @var{tol} * norm (@var{x}, Inf)) = 0
+## @end example
+## @var{tol} specifies the chopping tolerance. It defaults to 
+## 1e-10 for double precision and 1e-5 for single precision inputs.
+## @end deftypefn
+
+function x = ztvals (x, tol)
+  if (nargin == 1)
+    if (isa (x, 'single'))
+      tol = 1e-5;
+    else
+      tol = 1e-10;
+    endif
+  elseif (nargin != 2)
+    print_usage ();
+  endif
+
+  if (isfloat (x))
+    x(abs(x) < tol*norm (x, Inf)) = 0;
+  else
+    error ("ztvals: needs a floating-point argument");
+  endif
+
+endfunction