[R] ROCR package partial false positive and accuracy

[Saeed Abu Nimeh]

Hi,
In the ROCR package is there a way to find the accuracy that
corresponds to a given false positive rate. In version 1.0-2, the
authors of the package added an option to find the partial area under
the ROC curve up to a given false positive rate by passing an optional
parameter fpr.stop:
perf.auc<-performance(pred,"auc",fpr.stop=0.15)
Is there a way to find the accuracy up to a given false positive rate.
We use a classification tree (rpart) and a binary response.
Thanks, Saeed
---
R 2.8.1 Win XP pro
rpart 3.1-43
rocr 1.0-2