earth
object
evimp(object, trim=TRUE, sqrt.=TRUE)
earth
object.
TRUE
(default), delete rows in the returned matrix for
variables that don't appear in any subsets.
TRUE
,
meaning take the sqrt
of the GCV and RSS importances before
normalizing to 0 to 100.
Taking the square root gives a better indication of
relative importances because the raw importances are calculated using
a sum of squares.
Use FALSE
to not take the square root.
-unused
appended if the
variable does not appear in the final model.The columns of the matrix are (not all of these are printed by print.evimp
):
col
: Column index of the variable in the x
argument to earth
.
used
: 1 if the variable is used in the final model, else 0.
Equivalently, 0 if the row name has an -unused
suffix.
nsubsets
: Variable importance using the "number of subsets" criterion.
Is the number of subsets that include the variable (see "Three Criteria" in the chapter
on evimp
in the earth
vignette
“Notes on the earth package”).
gcv
: Variable importance using the GCV criterion (see "Three Criteria").
gcv.match
: 1, except is
0 where the rank using the gcv
criterion differs from
that using the nsubsets
criterion.
In other words, there is a 0 for values that increase as you go
down the gcv
column.
rss
: Variable importance using the RSS criterion (see "Three Criteria").
rss.match
: Like gcv.match
but for the rss
.
nsubsets
criterion.
This means that values in the nsubsets
column decrease as you go down the column
(more accurately, they are non-increasing).
The values in the gcv
and rss
columns
are also non-increasing, except where the
gcv
or rss
rank differs from the nsubsets
ranking.
earth
,
plot.evimp
data(ozone1)
earth.mod <- earth(O3 ~ ., data=ozone1, degree=2)
ev <- evimp(earth.mod, trim=FALSE)
plot(ev)
print(ev)
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