https://github.com/cran/fields
Tip revision: 6a574ee78277f7f38ae7939a12894c1616dc61eb authored by Douglas Nychka on 16 October 2015, 01:28:36 UTC
version 8.3-5
version 8.3-5
Tip revision: 6a574ee
fields.rdist.near.R
# fields, Tools for spatial data
# Copyright 2004-2013, Institute for Mathematics Applied Geosciences
# University Corporation for Atmospheric Research
# Licensed under the GPL -- www.gpl.org/licenses/gpl.html
fields.rdist.near <- function(x1, x2, delta, max.points = NULL,
mean.neighbor = 50) {
if (!is.matrix(x1))
x1 <- as.matrix(x1)
if (missing(x2))
x2 <- x1
if (!is.matrix(x2))
x2 <- as.matrix(x2)
d <- ncol(x1)
n1 <- nrow(x1)
n2 <- nrow(x2)
if (is.null(max.points)) {
Nmax <- n1 * mean.neighbor
}
else {
Nmax <- max.points
}
out <- .Fortran("ddfind",PACKAGE="fields",
nd = as.integer(d), x1 = as.double(x1),
n1 = as.integer(n1), x2 = as.double(x2), n2 = as.integer(n2),
D0 = as.double(delta), ind = as.integer(rep(0, Nmax *
2)), rd = as.double(rep(-1, Nmax)), Nmax = as.integer(Nmax),
iflag = as.integer(1))
N <- out$Nmax
if (out$iflag == -1) {
cat("temp space set at", Nmax, fill = TRUE)
stop("Ran out of space, increase max.points")
}
return(list(ind = matrix(out$ind, Nmax, 2)[1:N, ], ra = out$rd[1:N],
da = c(n1, n2)))
}