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#include "RunningStatistics.h"
#include "FloatDefine.h"
RunningStatistics::RunningStatistics() {
setWindowSecs( 1 ); // setup with one second average
setInitialValue( 0 ); // start with zero
}
void RunningStatistics::setWindowSecs( float windowSecs ) {
AverageSecs = windowSecs;
averageValue.setRiseTime( AverageSecs );
averageSquareValue.setRiseTime( AverageSecs );
}
void RunningStatistics::setInitialValue( float initialMean, float initialSigma ) {
averageValue.setToNewValue( initialMean );
averageSquareValue.setToNewValue( sq(initialMean) + sq(initialSigma ) );
}
void RunningStatistics::input( float inVal ) {
averageValue.input(inVal); // calculates running average
averageSquareValue.input(inVal*inVal); // calculates running average of square
}
float RunningStatistics::mean() {
return averageValue.output();
}
float RunningStatistics::variance() {
float var = averageSquareValue.output() - averageValue.output()*averageValue.output();
// because of the filtering, it's possible that this could be negative ... check!
if( var < 0 ) var = 0;
return var;
}
float RunningStatistics::sigma() {
#ifdef ARM_FLOAT
return sqrtf(variance());
#else
return sqrt(variance());
#endif
}
float RunningStatistics::CV() {
static const float maxCV = 1e3;
float meanTmp = mean();
// prevent divide by zero
if( meanTmp == 0 ) return maxCV;
else return sigma() / meanTmp;
}
void testRunningStatistics() {
// a speed test for running statistics
RunningStatistics myStats;
myStats.setInitialValue( (1.0/1024)*float(analogRead( A0 )) );
float updateInterval = 1.0;
float nextUpdateTime = 1e-6*float(micros()) + updateInterval;
long nLoops = 0;
while( true ) {
myStats.input( (1.0/1024)*float(analogRead( A0 )) );
nLoops++;
float t = 1e-6*float(micros());
if( t > nextUpdateTime ) {
nextUpdateTime += updateInterval;
Serial.print( "mean: "); Serial.print( myStats.mean() );
Serial.print( "\tsigma: " ); Serial.print( myStats.sigma() );
Serial.print( "\tHz: "); Serial.print( nLoops );
nLoops = 0;
Serial.print("\n");
}
}
}
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