spdiffpen | R Documentation |
spdiffpen
computes the m
th order spatial
difference penalty for a set of coordinates.
spdiffpen(coords, m = 1, sparse = TRUE, longlat = FALSE, digits = 1)
coords |
A two-dimensional matrix-like object with non-NULL dimensions. |
m |
A positive integer indicating order of the difference penalty. |
sparse |
A logical value indicating if the result
should be a sparse version of the
|
longlat |
A logical value indicating whether Great
Circle distances should be used ( |
digits |
The number of digits to use when applying
|
adjacent
is used to determine the
first-order neighbors of each point in coords
. The
difference penalties are then successively determined
from that.
If sparse = TRUE
, a
sparseMatrix-class
Matrix is
returned when the penalty matrix is relatively sparse
(typically, at least half the entries are zero).
Otherwise, something of the more general
Matrix-class
is returned.
A matrix
or sparseMatrix-class
object.
coords = expand.grid(1:4, 1:4)
# first order difference penalty
d1 = spdiffpen(coords, digits = 1)
# second order difference penalty
d2 = spdiffpen(coords, m = 2, digits = 1)
# third order difference penalty
d3 = spdiffpen(coords, m = 3, digits = 1)
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