droplinks | R Documentation |
Drops links to and from or just to a region from a neighbours list. The example corresponds to Fingleton's Table 1, p. 6, for lattices 5 to 19.
droplinks(nb, drop, sym=TRUE)
nb |
a neighbours list object of class |
drop |
either a logical vector the length of |
sym |
TRUE for removal of both "row" and "column" links, FALSE for only "row" links |
The function returns an object of class nb
with a list of integer vectors containing neighbour region number ids.
Roger Bivand Roger.Bivand@nhh.no
B. Fingleton (1999) Spurious spatial regression: some Monte Carlo results with a spatial unit root and spatial cointegration, Journal of Regional Science 39, pp. 1–19.
is.symmetric.nb
rho <- c(0.2, 0.5, 0.95, 0.999, 1.0) ns <- c(5, 7, 9, 11, 13, 15, 17, 19) mns <- matrix(0, nrow=length(ns), ncol=length(rho)) rownames(mns) <- ns colnames(mns) <- rho mxs <- matrix(0, nrow=length(ns), ncol=length(rho)) rownames(mxs) <- ns colnames(mxs) <- rho for (i in 1:length(ns)) { nblist <- cell2nb(ns[i], ns[i]) nbdropped <- droplinks(nblist, ((ns[i]*ns[i])+1)/2, sym=FALSE) listw <- nb2listw(nbdropped, style="W", zero.policy=TRUE) wmat <- listw2mat(listw) for (j in 1:length(rho)) { mat <- diag(ns[i]*ns[i]) - rho[j] * wmat res <- diag(solve(t(mat) %*% mat)) mns[i,j] <- mean(res) mxs[i,j] <- max(res) } } print(mns) print(mxs)
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