optdigit: Optical Recognition of Handwritten Digits of Frank A,...
In RSKC: Robust Sparse K-Means

Description Usage Arguments Details Author(s) References Examples

The dataset describes n = 1797 digits from 0 to 9 (K = 10), handwritten by 13 subjects. Raw observations are 32x32 bitmaps, which are divided into nonoverlapping blocks of 4x4 and the number of on pixels are counted in each block. This generates p = 64 (= 8x8) variable, recording the normalized counts of pixels in each block and each element is an integer in the range 0 to 16. The row names of the matrix optd contains the true labels (between 0 and 9), and the column names of it contains the position of the block in original bitmap.

1 2	data(optd) showbitmap(index)

index

A vector containing integers between 1 and 1797. Given the observation indices, the showbitmap returns their original 32 by 32 bitmaps on R console.

The original dataset is freely available from USIMachine Learning Repository (Frank and Asuncion (2010)) website http://archive .ics.uci.edu/ml/datasets.html.

Yumi Kondo <y.kondo@stat.ubc.ca>

Frank A, Asuncion A (2010). UCI Machine Learning Repository." http://archive.ics.uci.edu/ml.

## Not run: 

data(optd)

truedigit <- rownames(optd)
(re <- RSKC(optd,ncl=10,alpha=0.1,L1=5.7,nstart=1000))
Sensitivity(re$labels,truedigit)
table(re$labels,truedigit)

## Check the bitmap of the trimmed observations 
showbitmap(re$oW)
## Check the features which receive zero weights
names(which(re$weights==0))

## End(Not run)