practicalRangeCMB: Practical range for covariance function
Description
This function computes the practical range for covariance functions on spheres.
The function extends practicalRange from the
package geoR to additional covariance models on spheres.
A type of the correlation function. Available choices are: "matern",
"exponential","spherical", "powered.exponential", "cauchy", "gencauchy", "pure.nugget",
"askey", "c2wendland", "c4wendland", "sinepower", "multiquadric".
A smoothness parameter of the correlation function.
correlation
A correlation threshold (default is 0.05)
...
other optimisation parameters
Value
Value of the practical range for the covariance function specified in covmodelCMB
Details
The practical(effective) range for a covariance function is the distance at which
a covariance function first time reaches the specified value correlation. For
covariance functions on spheres the practical range does not exceed \(pi\), the
distance beyond which a covariance function is not defined. For the covariance
functions "spherical", "askey", "c2wendland", "c4wendland" their practical ranges
are equal to lengths of their support.