R/nntsdensity.R

In CircNNTSR: Statistical Analysis of Circular Data using Nonnegative Trigonometric Sums (NNTS) Models

nntsdensity <-
function (data, cpars = 1/sqrt(2*pi),M = 0) 
{
	data<-as.matrix(data)
	n<-nrow(data)
	R<-1
	if (R != length(M))
		return("Error: M must correspond to a univariate variable")

	if (length(cpars) != (M+1))
		return("Length of cpars must be equal to M+1")

	if (abs(sum(Mod(cpars)^2) - (1/(2 * pi))) > 0.0000000001) 
   		return("Sum of the squared norm of componentes does not satisfy condition")

	if (sum(M) == 0) 
            return(t(rep(1/(2 * pi),n)))

	gridcomb<-0:M

	statisticsmatrix<-matrix(0,nrow=M+1,ncol=n)

	statisticsmatrix<-exp(1i*gridcomb%*%t(data))

        aux <- t(cpars)%*%statisticsmatrix
        res <- aux * Conj(aux)
        return(t(Re(res)))
}