LHC <- function(theMatrix, npoints)
{
########################################################################
#Function:  LHC(theMatrix,theNames)
#
#Parameters:  theMatrix: an n by 2 matrix.  Each row is the lower
#                        and upper bound of the range of the variable.
#             colNames:  names of the variables
#             npoints: number of points each factor is chopped in (assuming uniform sampling)
########################################################################
#Description:  Function partitions the range of each variable into
#              evenly spaced intervals.  The number of intervals is 
#	            specified.  The function then randomly permutes
#	            the order of the intervals. The value returned by the 
#              function is matrix, where each row is a design point.  

	f <- function(m, n)
	{
		lb <- m[1]	  #lower bound
		ub <- m[2]	  #upper bound
		i <- (m[2] - m[1])/ (n-1)	     # interval step size
		return(seq(m[1] , m[2] , i))
	}
	
	hyper.design.temp <- apply(theMatrix, 1, f, npoints); # hyper.design.temp
	hyper.design <- apply(hyper.design.temp, 2, sample); # hyper.design
	return(hyper.design)
}


#-----------------test material

temp <- matrix(c(10,0,5,20,2,10), ncol=2); temp
npoints <- 21
out.design <- LHC(temp, npoints)
out.design