d2/filter/mult.h

   1 // Copyright 2004 David Hilvert <dhilvert@auricle.dyndns.org>,
   2 //                              <dhilvert@ugcs.caltech.edu>
   3
   4 /*  This file is part of the Anti-Lamenessing Engine.
   5
   6     The Anti-Lamenessing Engine is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     The Anti-Lamenessing Engine is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with the Anti-Lamenessing Engine; if not, write to the Free Software
  18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20
  21 #ifndef __mult_h__
  22 #define __mult_h__
  23
  24 /*
  25  * A class for pointwise multiplication of filters.
  26  */
  27
  28 class mult : public filter {
  29 private:
  30         ale_real _support;
  31         filter *f1, *f2;
  32 public:
  33
  34         /*
  35          * Size of filter support, in number of half-cycles to each side of the
  36          * filter center.
  37          */
  38         virtual ale_real support() const {
  39                 return _support;
  40         }
  41
  42         virtual int equals(const filter *f) const {
  43                 if (typeid(*f) != typeid(*this))
  44                         return 0;
  45
  46                 const mult *m = (const mult *)f;
  47
  48                 /*
  49                  * XXX: if we wished, we could recognize commutativity.
  50                  */
  51                 return (m->f1->equals(f1)
  52                      && m->f2->equals(f2));
  53         }
  54
  55         /*
  56          * Response of filter at point p
  57          */
  58         virtual ale_real response(point p) const {
  59                 return f1->response(p) * f2->response(p);
  60         }
  61
  62         mult(filter *f1, filter *f2) {
  63                 this->f1 = f1;
  64                 this->f2 = f2;
  65                 assert (f1 != NULL);
  66                 assert (f2 != NULL);
  67
  68                 _support = f1->support();
  69
  70                 if (f2->support() < _support)
  71                         _support = f2->support();
  72         }
  73
  74 };
  75 #endif