Find phi parameter for the Exponential spatial auto-correlation function

Function designed to find the phi paramter such that the correlation between points wihtin a given distance d is at most a given value.

Usage

find_phi(
  d,
  nu,
  kappa,
  mu2,
  family = "matern",
  range = c(1e-04, 1000),
  cut = 0.05
)

d: maximun distance for spatial dependence equal to cut.
nu: smoothness parameter associated with the Matern cov. function.
kappa: one of the smoothness parameters associated with the Generalized Wendland covariance function
mu2: one of the smoothness parameters associated with the Generalized Wendland covariance function
family: covariance function family, the options are c("matern", "gw", "cs", "spher", "pexp", "gaussian").
range: Minimum and maximum distance to be considered. The default is range = c(1e-04, 1000).
cut: desired spatial correlation at a distance d, the default is cut = .05.

a numeric value indicating the range parameter such that the spatial correlation between two points at distance d is cut.