if(y11*y22 == 0.0) c=1.0; else c = y12 / Math.sqrt(Math.abs(y11*y22));
if (y11 * y22 == 0.0) { c=1.0; } else { c = y12 / Math.sqrt(Math.abs(y11 * y22)); }
  public final static double correlation(double y1[],double y2[],int n) {    int i;    double av1=0.0,av2=0.0,y11=0.0,y22=0.0,y12=0.0,c;        if(n<=1)return 1.0;    for(i=0;i<n;i++){      av1 += y1[i];      av2 += y2[i];    }    av1 /= (double)n;    av2 /= (double)n;    for(i=0;i<n;i++){      y11 += (y1[i] - av1) * (y1[i] - av1);      y22 += (y2[i] - av2) * (y2[i] - av2);      y12 += (y1[i] - av1) * (y2[i] - av2);    }    if(y11*y22 == 0.0) c=1.0;    else c = y12 / Math.sqrt(Math.abs(y11*y22));        return c;  }