The Machine Perception Toolbox (MPT)

00001 /*
00002  * exponentioalaverager.cpp
00003  *
00004  * Copyright (c) 2003 Machine Perception Laboratory
00005  * University of California San Diego.
00006  * Please read the disclaimer and notes about redistribution
00007  * at the end of this file.
00008  *
00009  * Authors: Josh Susskind
00010  */
00011 
00012 #include "exponentialaverager.h"
00013 #include <ctime>
00014 #include <cmath>
00015 
00016 #include "../common.h"
00017 
00018 // ================================================================
00019 
00020 MPExponentialAverager::MPExponentialAverager() 
00021 : m_startFlag(true), 
00022   m_TimeEstimate(1),
00023   m_TimeCurrentBegin(getCurrTime()),
00024   m_TimeBegin(getCurrTime()) { }
00025 
00026 // ================================================================
00027 
00028 double MPExponentialAverager::getCurrTime() { 
00029         return (static_cast<double>(clock()));
00030 }
00031 
00032 // ================================================================
00033 
00034 void MPExponentialAverager::UpdateEstimate(double w) {
00035         m_TimeBegin = m_TimeCurrentBegin;
00036         double curr = getCurrTime()-m_TimeBegin;
00037         if (!m_startFlag) {
00038                 m_TimeEstimate = w*m_TimeEstimate + (1-w)*curr;
00039         } else {
00040                 m_TimeEstimate = curr;
00041                 m_startFlag = !m_startFlag;
00042         }
00043 }
00044 
00045 // ================================================================
00046 
00047 void MPExponentialAverager::updateTimeSearch() { 
00048         m_TimeCurrentBegin = getCurrTime(); 
00049 }
00050 
00051 // ================================================================
00052 
00053 double MPExponentialAverager::getTimeEstimate() { 
00054         return m_TimeEstimate; 
00055 }
00056 
00057 // ================================================================
00058 
00059 double MPExponentialAverager::getExponentialAvg(double alpha) {
00060         double timeConstant = -log(alpha) / getTimeEstimate();
00061         double diff = getCurrTime() - m_TimeBegin; 
00062         double expAvg = (1/alpha)*exp(-fabs(diff)*timeConstant);
00063         if (expAvg > 1) expAvg = 1;
00064         return expAvg;
00065 }
00066 
00067 // ================================================================
00068 
00069 /*
00070  * 
00071  * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
00072  * 
00073  *    1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
00074  *    2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
00075  *    3. The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission.
00076  * 
00077  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00078  * 
00079  */
The Machine Perception Toolbox

exponentialaverager.cpp
