# objfun.pmtree

From model4you v0.9-5
by Heidi Seibold

##### Objective function of a given pmtree

Returns the contributions to the objective function or the
sum thereof (if `sum = TRUE`

).

##### Usage

```
# S3 method for pmtree
objfun(x, newdata = NULL, weights = NULL,
perm = NULL, sum = FALSE, ...)
```

##### Arguments

- x
pmtree object.

- newdata
an optional new data frame for which to compute the sum of objective functions.

- weights
weights.

- perm
the number of permutations performed (see

`varimp`

).- sum
should the sum of objective functions be computed.

- ...
passed on to

`predict.party`

.Note that

`objfun.pmtree(x, sum = TRUE)`

is much faster than`sum(objfun.pmtree(x))`

.

##### Value

objective function or the sum thereof

##### Examples

```
# NOT RUN {
## generate data
set.seed(2)
n <- 1000
trt <- factor(rep(1:2, each = n/2))
age <- sample(40:60, size = n, replace = TRUE)
eff <- -1 + I(trt == 2) + 1 * I(trt == 2) * I(age > 50)
expit <- function(x) 1/(1 + exp(-x))
success <- rbinom(n = n, size = 1, prob = expit(eff))
dat <- data.frame(success, trt, age)
## compute base model
bmod1 <- glm(success ~ trt, data = dat, family = binomial)
## copmute tree
(tr1 <- pmtree(bmod1, data = dat))
## compute log-Likelihood
logLik(tr1)
objfun(tr1, newdata = dat, sum = TRUE)
objfun(tr1, sum = TRUE)
## log-Likelihood contributions of first
## 5 observations
nd <- dat[1:5, ]
objfun(tr1, newdata = nd)
# }
```

*Documentation reproduced from package model4you, version 0.9-5, License: GPL-2 | GPL-3*

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