do.ammc {Rdimtools}

Adaptive Maximum Margin Criterion

Description

Adaptive Maximum Margin Criterion (AMMC) is a supervised linear dimension reduction method. The method uses different weights to characterize the different contributions of the training samples embedded in MMC framework. With the choice of a=0, b=0, and lambda=1, it is identical to standard MMC method.

Usage

do.ammc(
  X,
  label,
  ndim = 2,
  preprocess = c("center", "scale", "cscale", "decorrelate", "whiten"),
  a = 1,
  b = 1,
  lambda = 1
)

Arguments

X

an (n\times p) matrix or data frame whose rows are observations and columns represent independent variables.

label

a length-n vector of data class labels.

ndim

an integer-valued target dimension.

preprocess

an additional option for preprocessing the data. Default is "center". See also aux.preprocess for more details.

a

tuning parameter for between-class weight in [0,\infty).

b

tuning parameter for within-class weight in [0,\infty).

lambda

balance parameter for between-class and within-class scatter matrices in (0,\infty).

Value

a named list containing

Y

an (n\times ndim) matrix whose rows are embedded observations.

trfinfo

a list containing information for out-of-sample prediction.

projection

a (p\times ndim) whose columns are basis for projection.

Author(s)

Kisung You

References

Lu J, Tan Y (2011). “Adaptive Maximum Margin Criterion for Image Classification.” In 2011 IEEE International Conference on Multimedia and Expo, 1–6.

See Also

do.mmc

Examples

## 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])

## try different lambda values
out1 = do.ammc(X, label, lambda=0.1)
out2 = do.ammc(X, label, lambda=1)
out3 = do.ammc(X, label, lambda=10)

## visualize
opar <- par(no.readonly=TRUE)
par(mfrow=c(1,3))
plot(out1$Y, main="AMMC::lambda=0.1", pch=19, cex=0.5, col=label)
plot(out2$Y, main="AMMC::lambda=1",   pch=19, cex=0.5, col=label)
plot(out3$Y, main="AMMC::lambda=10",  pch=19, cex=0.5, col=label)
par(opar)