computes phi1 function, internally used to compute the weights for the algorithm

computes phi1 function, internally used to compute the weights for the algorithm

phi1(delta, c2, k2, ese, dis, p)

Arguments

delta	positive definite p x p matrix, the estimated covariance of errors
c2	constant for rho_2 function
k2	constant for rho_2 function
ese	real positive number, the s-cale of distances
dis	vector of distances
p	dimension of ambient space