do.fastmap
is an implementation of FastMap algorithm. Though
it shares similarities with MDS, it is innately a nonlinear method that makes an iterative update
for the projection information using pairwise distance information.
do.fastmap(
X,
ndim = 2,
preprocess = c("null", "center", "scale", "cscale", "whiten", "decorrelate")
)
an \((n\times p)\) matrix or data frame whose rows are observations and columns represent independent variables.
an integer-valued target dimension.
an additional option for preprocessing the data.
Default is "null". See also aux.preprocess
for more details.
a named list containing
an \((n\times ndim)\) matrix whose rows are embedded observations.
a list containing information for out-of-sample prediction.
Faloutsos C, Lin K (1995). “FastMap: A Fast Algorithm for Indexing, Data-Mining and Visualization of Traditional and Multimedia Datasets.” In Proceedings of the 1995 ACM SIGMOD International Conference on Management of Data - SIGMOD '95, 163--174.
if (FALSE) {
## load iris data
data(iris)
set.seed(100)
subid = sample(1:150,50)
X = as.matrix(iris[subid,1:4])
label = as.factor(iris[subid,5])
## let's compare with other methods
out1 <- do.pca(X, ndim=2) # PCA
out2 <- do.mds(X, ndim=2) # Classical MDS
out3 <- do.fastmap(X, ndim=2) # FastMap
## visualize
opar = par(no.readonly=TRUE)
par(mfrow=c(1,3))
plot(out1$Y, pch=19, col=label, main="PCA")
plot(out2$Y, pch=19, col=label, main="MDS")
plot(out3$Y, pch=19, col=label, main="FastMap")
par(opar)
}