earth (version 2.3-0)

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
#    Estimated importance: temp humidity ibt doy dpg ibh vis wind
#    Number of terms at each degree of interaction: 1 5 5
#    GCV 13.4    RSS 3762    GRSq 0.791    RSq 0.822

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

# yields:
#    Selected 15 of 21 terms, and 8 of 8 predictors
#    Estimated importance: ibt humidity doy vh ibh dpg wind vis
#    Number of terms at each degree of interaction: 1 5 9
#    GCV 13.1    RSS 3443    GRSq 0.796    RSq 0.837

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

# yields:
#    Selected 8 of 21 terms, and 6 of 9 predictors
#    Estimated importance: temp humidity ibt doy dpg vis
#    Number of terms at each degree of interaction: 1 5 2
#    GCV 15.1    RSS 4434    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
#    Estimated importance: temp humidity ibt doy dpg ibh vis wind
#    Number of terms at each degree of interaction: 1 5 7
#    GCV 12.5    RSS 3675    GRSq 0.805    RSq 0.826