BRISC (version 1.0.5)

BRISC_order: Function for ordering coordinates with BRISC

Description

The function BRISC_order outputs the ordering for a set of coordinates, which can be used as an input for "ordering" argument in BRISC_estimation. This is especially useful for avoiding often computationally intensive location ordering scheme in case of multiple application of BRISC_estimation on a fixed set of coordinates.

Usage

BRISC_order(coords, order = "Sum_coords", verbose = TRUE)

Value

An integer vector of ordering of the input coordinates which can be used as an input for

"ordering" argument in BRISC_estimation.

Arguments

coords

an \(n \times 2\) matrix of the observation coordinates in \(R^2\) (e.g., easting and northing).

order

keyword that specifies the ordering scheme to be used in ordering the observations. Supported keywords are: "AMMD" and "Sum_coords" for approximate Maximum Minimum Distance and sum of coordinate based ordering, respectively. Default value is "Sum_coords". \(n > 65\) is required for "AMMD".

verbose

if TRUE, progress of the algorithm is printed to the screen. Otherwise, nothing is printed to the screen. Default value is TRUE.

Author

Arkajyoti Saha ,
Abhirup Datta

References

Saha, A., & Datta, A. (2018). BRISC: bootstrap for rapid inference on spatial covariances. Stat, e184, DOI: 10.1002/sta4.184.

Datta, A., S. Banerjee, A.O. Finley, and A.E. Gelfand. (2016) Hierarchical Nearest-Neighbor Gaussian process models for large geostatistical datasets. Journal of the American Statistical Association, 111:800-812.

Guinness, J. (2018) Permutation and Grouping Methods for Sharpening Gaussian Process Approximations, Technometrics, DOI: 10.1080/00401706.2018.1437476,
https://github.com/joeguinness/gp_reorder/tree/master/R .

Examples

set.seed(1)
n <- 1000
coords <- cbind(runif(n,0,1), runif(n,0,1))


ordering_result <- BRISC_order(coords)