Supervised Laplacian Eigenmaps (SPLAPEIG) is a supervised variant of Laplacian Eigenmaps.
Instead of setting up explicit neighborhood, it utilizes an adaptive threshold strategy
to define neighbors for both within- and between-class neighborhood. It then builds affinity
matrices for each information and solves generalized eigenvalue problem. This algorithm
may be quite sensitive in the choice of beta
value.
do.splapeig(
X,
label,
ndim = 2,
preprocess = c("null", "center", "scale", "cscale", "whiten", "decorrelate"),
beta = 1,
gamma = 0.5
)
an \((n\times p)\) matrix or data frame whose rows are observations and columns represent independent variables.
a length-\(n\) vector of data class labels.
an integer-valued target dimension.
an additional option for preprocessing the data.
Default is "null". See also aux.preprocess
for more details.
bandwidth parameter for heat kernel in \([0,\infty)\).
a balancing parameter in \([0,1]\) between within- and between-class information.
a named list containing
an \((n\times ndim)\) matrix whose rows are embedded observations.
a list containing information for out-of-sample prediction.
Raducanu B, Dornaika F (2012). “A Supervised Non-Linear Dimensionality Reduction Approach for Manifold Learning.” Pattern Recognition, 45(6), 2432--2444.
# \donttest{
## load iris data
data(iris)
X = as.matrix(iris[,1:4])
label = as.factor(iris[,5])
## try different balancing parameters with beta=50
out1 = do.splapeig(X, label, beta=50, gamma=0.3); Y1=out1$Y
out2 = do.splapeig(X, label, beta=50, gamma=0.6); Y2=out2$Y
out3 = do.splapeig(X, label, beta=50, gamma=0.9); Y3=out3$Y
## visualize
opar <- par(no.readonly=TRUE)
par(mfrow=c(1,3))
plot(Y1, pch=19, col=label, main="gamma=0.3")
plot(Y2, pch=19, col=label, main="gamma=0.6")
plot(Y3, pch=19, col=label, main="gamma=0.9")
#> Warning: relative range of values ( 83 * EPS) is small (axis 2)
par(opar)
# }