R/is.exp.R

In DnE: Distribution and Equation

is.exp <-
function(x,m,a=10,lambda=NULL)
{
	re=1;
	for(i in 1:length(x))
		if(x[i]<0)
			re=-1;
	p=rep(0,m+1);
	y=rep(0,m+1);
	q=0;
	if(re==-1)
	{
		return(data.frame("state"=-1,"pvalue"=1));
	}
	else
	{
		if(is.null(lambda))
		{
			lambda=1/mean(x);
			df=m-1;
		}
		else
		{
			df=m;
		}
		if(lambda>0)
		{
			di=max(x);
			for(i in 1:m)
			{
				p[i]=pexp(di*i/m,lambda)-pexp(di*(i-1)/m,lambda);
			 if(p[i]==0)
			{
				break;
			}
				for(j in 1:length(x))
					if(x[j]>di*(i-1)/m && x[j]<=di*i/m)
						y[i]=y[i]+1;
				q=q+(y[i]-(length(x)*p[i]))^2/(length(x)*p[i]);
			}
			p[m+1]=pexp(Inf,lambda)-pexp(max(x),lambda);
			q=q+length(x)*p[m+1];
			q0=qchisq(1-a,df);
                        pvalue=pchisq(q,df);
			if(q<=q0)
			{
				return(data.frame("qchisq"=q,"pvalue"=pvalue));
			}
			else
			{
				return(data.frame("state"=-1,"pvalue"=1));
			}
		}
		else
		{
			return(data.frame("state"=-1,"pvalue"=1));
		}
	}
}