Download Plotting rpart trees with prp

A
Appendix: mvpart mrt models
Note: In December 2014 the mvpart package was removed from CRAN.
The extra argument of prp has a special meaning for mvpart mrt models [1], as shown in the figure below.
(Internally, mvpart sets the method field of the tree to "mrt", and prp recognizes that.) As always you can
print percentages by adding 100 to extra. The type and other arguments work in the usual way.
Example:
library(rpart.plot)
library(mvpart)
data(spider)
set.seed(10)
response <- data.matrix(spider[,1:3, drop=F])
tree <- mvpart(response~herbs+reft+moss+sand+twigs+water, data=spider,
method="mrt", xv="min")
prp(tree, type=1, extra=111, under=TRUE)
extra = 0
dev
extra = 1
dev, n
water < 5.5
165
twigs >= 8
8.3
103
extra = 2
dev, frac
water < 5.5
165
water < 5.5
165
water < 5.5
165
n=28
.36 1.18 1.54
.12 .38 .50
8.3
twigs >= 8
8.3
twigs >= 8
8.3
n=12
103
.00 .17 .33
103
.00 .33 .67
n=16
26
19
extra = 4
sqrt(dev)
13
twigs >= 8
26
19
n=8
n=8
26
19
.00 .75 .25
.21 .15 .65
extra = 6
sqrt(dev), frac
twigs >= 8
zora.spin
water < 5.5
13
n=28
.36 1.18 1.54
.12 .38 .50
2.9
twigs >= 8
2.9
twigs >= 8
2.9
n=12
10
.00 .17 .33
10
.00 .33 .67
twigs >= 8
10
.12 .39 .49
.62 1.94 2.44
5.1
4.4
n=8
n=8
extra = 9
predom species, n
5.1
4.4
5.1
4.4
.00 3.00 1.00
1.25 .88 3.88
.00 .75 .25
.21 .15 .65
extra = 10
predom species, frac
extra = 11
predom spec, frac / sum(frac)
water < 5.5
zora.spin
water < 5.5
zora.spin
water < 5.5
zora.spin
n=28
.36 1.18 1.54
.12 .38 .50
zora.spin
twigs >= 8
zora.spin
n=12
n=16
zora.spin
extra = 7
sqrt(dev), frac / sum(frac)
13
4.4
pard.lugu
19
1.25 .88 3.88
water < 5.5
water < 5.5
zora.spin
zora.spin
26
.00 3.00 1.00
n=16
extra = 8
predom species
103
.12 .39 .49
water < 5.5
13
10
5.1
twigs >= 8
.62 1.94 2.44
extra = 5
sqrt(dev), n
water < 5.5
2.9
extra = 3
dev, frac / sum(frac)
zora.spin
twigs >= 8
zora.spin
.00 .17 .33
zora.spin
.00 .33 .67
.62 1.94 2.44
pard.lugu
zora.spin
n=8
n=8
.12 .39 .49
pard.lugu
zora.spin
pard.lugu
.00 3.00 1.00
1.25 .88 3.88
.00 .75 .25
Figure 24: The extra argument with an mrt model.
27
twigs >= 8
zora.spin
zora.spin
.21 .15 .65