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- ## Copyright (C) 1995, 1996 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} {} nextpow2 (@var{x})
- ## If @var{x} is a scalar, returns the first integer @var{n} such that
- ## @iftex
- ## @tex
- ## $2^n \ge |x|$.
- ## @end tex
- ## @end iftex
- ## @ifinfo
- ## 2^n >= abs (x).
- ## @end ifinfo
- ##
- ## If @var{x} is a vector, return @code{nextpow2 (length (@var{x}))}.
- ## @end deftypefn
-
- ## See also: pow2
-
- ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
- ## Created: 7 October 1994
- ## Adapted-By: jwe
-
- function n = nextpow2 (x)
-
- if (nargin != 1)
- usage ("nextpow2 (x)");
- endif
-
- if (! (is_scalar (x) || is_vector (x)))
- error ("nextpow2: x must be a scalar or a vector");
- endif
-
- t = length (x);
- if (t > 1)
- x = t;
- endif
-
- [f, n] = log2 (abs (x));
- if (f == 0.5)
- n = n - 1;
- endif
-
- endfunction
-