Optimized Learning Vector Quantization 1

Moves examples in a codebook to better represent the training set.

olvq1(x, cl, codebk, niter = 40 * nrow(codebk$x), alpha = 0.3)

Arguments

x

a matrix or data frame of examples

cl

a vector or factor of classifications for the examples

codebk

a codebook

niter

number of iterations

alpha

constant for training

Value

A codebook, represented as a list with components x and cl giving the examples and classes.

Details

Selects niter examples at random with replacement, and adjusts the nearest example in the codebook for each.

References

Kohonen, T. (1990) The self-organizing map. Proc. IEEE 78, 1464–1480.

Kohonen, T. (1995) Self-Organizing Maps. Springer, Berlin.

Ripley, B. D. (1996) Pattern Recognition and Neural Networks. Cambridge.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

See also

lvqinit, lvqtest, lvq1, lvq2, lvq3

Examples

train <- rbind(iris3[1:25,,1], iris3[1:25,,2], iris3[1:25,,3])
test <- rbind(iris3[26:50,,1], iris3[26:50,,2], iris3[26:50,,3])
cl <- factor(c(rep("s",25), rep("c",25), rep("v",25)))
cd <- lvqinit(train, cl, 10)
lvqtest(cd, train)
#>  [1] s s s s s s s s s s s s s s s s s s s s s s s s s c c c c c c c c c c c c c
#> [39] c c c c c c c c c v c c v v v v v v c v v v c v v v v v v v v v v v v v v
#> Levels: c s v
cd1 <- olvq1(train, cl, cd)
lvqtest(cd1, train)
#>  [1] s s s s s s s s s s s s s s s s s s s s s s s s s c c c c c c c c c c c c c
#> [39] c c c c c c c c c c c c v v v v v v v v v v v v v v v v v v v v v v v v v
#> Levels: c s v