Marsyas  0.6.0-alpha
/usr/src/RPM/BUILD/marsyas-0.6.0/src/marsyas/marsystems/Skewness.cpp
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00001 /*
00002 ** Copyright (C) 1998-2006 George Tzanetakis <gtzan@cs.uvic.ca>
00003 **
00004 ** This program is free software; you can redistribute it and/or modify
00005 ** it under the terms of the GNU General Public License as published by
00006 ** the Free Software Foundation; either version 2 of the License, or
00007 ** (at your option) any later version.
00008 **
00009 ** This program is distributed in the hope that it will be useful,
00010 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
00011 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012 ** GNU General Public License for more details.
00013 **
00014 ** You should have received a copy of the GNU General Public License
00015 ** along with this program; if not, write to the Free Software
00016 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
00017 */
00018 
00019 #include "Skewness.h"
00020 #include "../common_source.h"
00021 
00022 using namespace std;
00023 using namespace Marsyas;
00024 
00025 Skewness::Skewness(mrs_string name):MarSystem("Skewness",name)
00026 {
00027   //type_ = "Skewness";
00028   //name_ = name;
00029 }
00030 
00031 
00032 Skewness::~Skewness()
00033 {
00034 }
00035 
00036 
00037 MarSystem*
00038 Skewness::clone() const
00039 {
00040   return new Skewness(*this);
00041 }
00042 
00043 
00044 void
00045 Skewness::myUpdate(MarControlPtr sender)
00046 {
00047   (void) sender;  //suppress warning of unused parameter(s)
00048   MRSDIAG("Skewness.cpp - Skewness:myUpdate");
00049 
00050   setctrl("mrs_natural/onSamples", getctrl("mrs_natural/inSamples"));
00051   setctrl("mrs_natural/onObservations", (mrs_natural)1);
00052   setctrl("mrs_real/osrate", getctrl("mrs_real/israte"));
00053   setctrl("mrs_string/onObsNames", "Skewness,");
00054 
00055   //defaultUpdate();[!]
00056   inObservations_ = getctrl("mrs_natural/inObservations")->to<mrs_natural>();
00057 
00058   obsrow_.create(inObservations_);
00059 }
00060 
00061 
00062 void
00063 Skewness::myProcess(realvec& in, realvec& out)
00064 {
00065   mrs_natural t,o;
00066 
00067   for (t = 0; t < inSamples_; t++)
00068   {
00069 
00070     for (o=0; o < inObservations_; o++)
00071     {
00072       obsrow_(o) = in(o,t);
00073     }
00074     z_ = 0.0;
00075     for (o=0; o < inObservations_; o++)
00076     {
00077       b_ =  obsrow_(o) - obsrow_.mean() ;
00078 
00079       // take x - mean to the third power into the sum
00080       z_ += (b_ * b_ * b_);
00081     }
00082     if (z_ > 1.0e-45)
00083       z_ /= inObservations_;
00084     else
00085       z_ = 0.0;
00086 
00087 
00088     // standard deviation to the fourth power
00089     q_ = pow(obsrow_.var(), (mrs_real)1.5);
00090 
00091     if ((q_ < 1.0e-45)||(z_== 1.0e-45))
00092       out(0,t) = 0.5;
00093     else
00094       out(0,t) = (z_ / q_)  / inObservations_;
00095   }
00096 
00097 }