# l1ce

From lasso2 v1.2-0
by Martin Maechler

##### Regression Fitting With L1-constraint on the Parameters

Returns an object of class `"l1ce"`

or `"licelist"`

that represents
fit(s) of linear models while imposing L1 constraint(s) on the parameters.

- Keywords
- models, regression, optimize

##### Usage

```
l1ce(formula, data = sys.parent(), weights, subset, na.action,
sweep.out = ~ 1, x = FALSE, y = FALSE,
contrasts = NULL, standardize = TRUE,
trace = FALSE, guess.constrained.coefficients = double(p),
bound = 0.5, absolute.t = FALSE)
```

##### Value

an object of class `l1ce`

(if `bound`

was a single value) or
`l1celist`

(if `bound`

was a vector of values) is returned.
See `l1ce.object`

and `l1celist.object`

for details.

##### References

Osborne, M.R., Presnell, B. and Turlach, B.A. (2000)
On the LASSO and its Dual,
*Journal of Computational and Graphical Statistics*
**9**(2), 319--337.

Tibshirani, R. (1996)
Regression shrinkage and selection via the lasso,
*Journal of the Royal Statistical Society, Series B*
**58**(1), 267--288.

##### Examples

```
data(Iowa)
l1c.I <- l1ce(Yield ~ ., Iowa, bound = 10, absolute.t=TRUE)
l1c.I
## The same, printing information in each step:
l1ce(Yield ~ ., Iowa, bound = 10, trace = TRUE, absolute.t=TRUE)
data(Prostate)
l1c.P <- l1ce(lpsa ~ ., Prostate, bound=(1:30)/30)
length(l1c.P)# 30 l1ce models
l1c.P # -- MM: too large; should do this in summary(.)!
<testonly>str(l1c.P, max.lev = 1)</testonly>
plot(resid(l1c.I) ~ fitted(l1c.I))
abline(h = 0, lty = 3, lwd = .2)
```

*Documentation reproduced from package lasso2, version 1.2-0, License: GPL version 2 or later*

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