Find extreme eigenvalues of binary symmetric spatial weights
The functions find extreme eigenvalues of binary symmetric spatial weights, when these form planar graphs; general weights are not permiited. l_max
finds the largest eigenvalue using Rayleigh quotient methods of any “listw” object. lextrB
first calls l_max
, and uses its output to find the smallest eigenvalue in addition for binary symmetric spatial weights. lextrW
extends these to find the smallest eigenvalue for intrinsically symmetric row-standardized binary weights matrices (transformed to symmetric through similarity internally). lextrS
does the same for variance-stabilized (“S” style) intrinsically symmetric binary weights matrices (transformed to symmetric through similarity internally).
lextrB(lw, zero.policy = TRUE, control = list()) lextrW(lw, zero.policy=TRUE, control=list()) lextrS(lw, zero.policy=TRUE, control=list()) l_max(lw, zero.policy=TRUE, control=list())
lw |
a binary symmetric |
zero.policy |
default NULL, use global option value; if TRUE assign zero to the lagged value of zones without neighbours, if FALSE assign NA |
control |
a list of control arguments |
The functions return approximations to the extreme eigenvalues with the eigenvectors returned as attributes of this object.
report values in while loops, default NULL assuming FALSE; logical
tolerance for breaking while loops, default .Machine$double.eps^(1/2)
; numeric
maximum number of iterations in while loops, default 6 * (length(lw$neighbours) - 2
; integer
use C code, default TRUE, logical (not in l_max
)
It may be necessary to modify control arguments if warnings about lack of convergence are seen.
Roger Bivand, Yongwan Chun, Daniel Griffith
Griffith, D. A. (2004). Extreme eigenfunctions of adjacency matrices for planar graphs employed in spatial analyses. Linear Algebra and its Applications, 388:201–219.
data(boston, package="spData") #require(spdep, quietly=TRUE) ab.listb <- spdep::nb2listw(boston.soi, style="B") er <- range(eigenw(ab.listb)) er res_1 <- lextrB(ab.listb) c(res_1) run <- FALSE if (require("RSpectra", quietly=TRUE)) run <- TRUE if (run) { B <- as(ab.listb, "CsparseMatrix") eigs(B, k=1, which="SR")$values } if (run) { eigs(B, k=1, which="LR")$values } k5 <- spdep::knn2nb(spdep::knearneigh(boston.utm, k=5)) c(l_max(spdep::nb2listw(k5, style="B"))) max(Re(eigenw(spdep::nb2listw(k5, style="B")))) c(l_max(spdep::nb2listw(k5, style="C"))) max(Re(eigenw(spdep::nb2listw(k5, style="C")))) ab.listw <- spdep::nb2listw(boston.soi, style="W") er <- range(eigenw(similar.listw(ab.listw))) er res_1 <- lextrW(ab.listw) c(res_1) if (run) { B <- as(similar.listw(ab.listw), "CsparseMatrix") eigs(B, k=1, which="SR")$values } if (run) { eigs(B, k=1, which="LR")$values } ## Not run: ab.listw <- spdep::nb2listw(boston.soi, style="S") er <- range(eigenw(similar.listw(ab.listw))) er res_1 <- lextrS(ab.listw) c(res_1) ## End(Not run) if (run) { B <- as(similar.listw(ab.listw), "CsparseMatrix") eigs(B, k=1, which="SR")$values } if (run) { eigs(B, k=1, which="LR")$values }
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