KNex {Matrix} R Documentation

## Koenker-Ng Example Sparse Model Matrix and Response Vector

### Description

A model matrix mm and corresponding response vector y used in an example by Koenker and Ng. The matrix mm is a sparse matrix with 1850 rows and 712 columns but only 8758 non-zero entries. It is a "dgCMatrix" object. The vector y is just numeric of length 1850.

### Usage

data(KNex)

### References

Roger Koenker and Pin Ng (2003). SparseM: A sparse matrix package for R; J. of Statistical Software, 8 (6), doi:10.18637/jss.v008.i06

### Examples

data(KNex)
class(KNex$mm) dim(KNex$mm)
image(KNex\$mm)
str(KNex)

system.time( # a fraction of a second
sparse.sol <- with(KNex, solve(crossprod(mm), crossprod(mm, y))))