adjust.sigma2: Adjustment factor for the variance of the convolution of...
In PrevMap: Geostatistical Modelling of Spatially Referenced Prevalence Data

Description Usage Arguments Details Value Author(s) See Also

This function computes the multiplicative constant used to adjust the value of sigma2 in the low-rank approximation of a Gaussian process.

1	adjust.sigma2(knots.dist, phi, kappa)

`knots.dist`	a matrix of the distances between the observed coordinates and the spatial knots.
`phi`	scale parameter of the Matern covariance function.
`kappa`	shape parameter of the Matern covariance function.

Let U denote the n by m matrix of the distances between the n observed coordinates and m pre-defined spatial knots. This function computes the following quantity

\frac{1}{n}∑_{i=1}^n ∑_{j=1}^m K(u_{ij}; φ, κ)^2,

where K(.; φ, κ) is the Matern kernel (see matern.kernel) and u_{ij} is the distance between the i-th sampled location and the j-th spatial knot.

A value corresponding to the adjustment factor for sigma2.

Emanuele Giorgi e.giorgi@lancaster.ac.uk

Peter J. Diggle p.diggle@lancaster.ac.uk

matern.kernel, pdist.

PrevMap documentation built on Oct. 7, 2021, 5:07 p.m.