chebyshev.java

// chebysheve outlier detection // this function is used to detect the abnormal value among a set o

////////////////////////////////////////////////////////////
// chebysheve outlier detection
// this function is used to detect the abnormal value among a set of data
// input:
//       delta: a set of data
//       flag: discribe which data is already known as outlier
//	 p:   restrict level
// output:
//      double[] door : byyond which the data may be considered as a outlier
//      door[0]: the upperdoor
//      door[1]: the lowerdoor
////////////////////////////////////////////////////////////

import java.lang.Math; 

class chebyshev{
// for debug
/*	public static void main(String args[]){
		double[] delta= new double[10];
		boolean[] flag=new boolean[10];
		for (int i=0;i<=9;i++){
			delta[i]=1;
			flag[i]=false;
		}
		double[] door=new double[2];
		door=chebyshev.chebyshev1(delta, flag, 3);
		System.out.println(door[0]);
		System.out.println(door[1]);
		
	}
*/

public static double[] chebyshev1(double[] delta, boolean[] flag, double k){

	//compute mean value and standerd deviation without error const point
	//DX: standard	deviation ;; EX: mean
	double EX=0;
	double DX=0;
	double[] door=new double[2];
	int n=0;
	for(int i=0;i<=delta.length-1;++i)
	{
		if(flag[i]==false)
		{
			EX+=delta[i];
			++n;
		}
	}
	EX=EX/n;
	double EXsquire=0;
	n=0;
	for(int j=0;j<=delta.length-1;++j)
	{
		if(flag[j]==false)	
		{
			EXsquire+=delta[j]*delta[j];
			++n;
		}
	}
	
	DX=EXsquire/n-EX*EX;
	DX=Math.sqrt(DX);
	

	door[0]=EX+k*DX;
	door[1]=EX-k*DX;
	return door;
}
}