[R] new version of glmnet
Trevor Hastie
hastie at stanford.edu
Sat Jan 24 18:34:38 CET 2009
glmnet _1.1-3 is on CRAN now.
glmnet fits lasso and elastic net regularization paths for squared
error, binomial and multinomial
models via coordinate descent. It is extremely fast and can work on
large scale problems.
See the paper: "Regularized Paths for Generalized Linear Models via
Coordinate Descent" by
Friedman, Hastie, Tibshirani on my website for details.
Glmnet can accommodate sparse data matrices efficiently, and thereby
handle even larger problems.
For example for a two class logistic model with 11K obs and 750K
variables (with > 99% zeros in X matrix),
glmnet takes less than two minutes to fit the entire regularization
path on a grid of 100 values of the
reg. parameter lambda. For a 14-class gene expression dataset (144
obs, 16K vars, not sparse), it takes 15 seconds
to fit the path at 100 values of lambda
Several minor fixes, as well as two more serious fixes:
1) predict( ...,type="class") was returning flipped labels for a two
class logistic model.
2) if a weight argument was supplied to binomial/multinomial model,
with some zero weight entries,
the program bombed with an unhelpful message. Now it works as expected.
Thanks to many users, esp. Tim Hesterberg, for notifying us of the
errors.
Trevor Hastie
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