The diabetes data frame has 442 rows and 3 columns. These are the
data used in the Efron et al "Least Angle Regression" paper.
This data frame contains the following columns:
x a matrix with 10 columns
y a numeric vector
x2 a matrix with 64 columns
https://web.stanford.edu/~hastie/Papers/LARS/LeastAngle_2002.pdf
The x matrix has been standardized to have unit L2 norm in each column and zero mean. The matrix x2 consists of x plus certain interactions.
Efron, Hastie, Johnstone and Tibshirani (2003) "Least Angle Regression" (with discussion) Annals of Statistics