earth (version 2.5-1)

update.earth: Update an "earth" model

Description

Update an earth model.

Usage

## S3 method for class 'earth':
update(object = stop("no 'object' arg"),
       formula. = NULL, ponly = FALSE, ..., evaluate = TRUE)

Arguments

object

The earth object

formula.

The formula. argument is treated like earth's formula argument.

ponly

Force pruning only, no forward pass. Default is FALSE, meaning update.earth decides automatically if a forward pass is needed. See note below.

...

Arguments passed on to earth.

evaluate

If TRUE (default) evaluate the new call, else return the call. Mostly for compatibility with the generic update.

Value

• The value is the same as that returned by earth. If object is the only parameter then no changes are made --- the returned value will be the same as the original object.

See Also

earth

Examples

data(ozone1)
(a <- earth(O3 ~ ., data = ozone1, degree = 2))

# yields:
#    Selected 11 of 21 terms, and 8 of 9 predictors
#    Importance: temp, humidity, ibt, doy, dpg, ibh, vis, wind, vh-unused
#    Number of terms at each degree of interaction: 1 5 5
#    GCV 13.5    RSS 3768    GRSq 0.791    RSq 0.822

update(a, formula = O3 ~ . - temp) # requires forward pass and pruning

# yields:
#    Selected 14 of 21 terms, and 8 of 8 predictors
#    Importance: ibt, humidity, doy, vh, ibh, dpg, wind, vis
#    Number of terms at each degree of interaction: 1 5 8
#    GCV 13.1    RSS 3499    GRSq 0.796    RSq 0.834

update(a, nprune = 8)              # requires only pruning

# yields:
#    Selected 8 of 21 terms, and 6 of 9 predictors
#    Importance: temp, humidity, ibt, doy, dpg, ibh-unused, vis, vh-unused, wind-unused
#    Number of terms at each degree of interaction: 1 5 2
#    GCV 15.1    RSS 4435    GRSq 0.766    RSq 0.79

update(a, penalty=1, ponly=TRUE)   # pruning pass only with a new penalty

# yields:
#    Selected 13 of 21 terms, and 8 of 9 predictors
#    Importance: temp, humidity, ibt, doy, dpg, ibh, vis, wind, vh-unused
#    Number of terms at each degree of interaction: 1 5 7
#    GCV 12.5    RSS 3671    GRSq 0.805    RSq 0.826