BRISC_order {BRISC}

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)

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.

Value

An integer vector of ordering of the input coordinates which can be used as an input for "ordering" argument in BRISC_estimation.

Author(s)

Arkajyoti Saha [e-mail],
Abhirup Datta [e-mail]

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)