| apk {Metrics} | R Documentation |
Average Precision at k
Description
apk computes the average precision at k, in the context of information
retrieval problems.
Usage
apk(k, actual, predicted)
Arguments
k |
The number of elements of |
actual |
The ground truth vector of relevant documents. The vector can contain
any numeric or character values, order does not matter, and the
vector does not need to be the same length as |
predicted |
The predicted vector of retrieved documents. The vector can
contain any numeric of character values. However, unlike |
Details
apk loops over the first k values of predicted. For each value, if
the value is contained within actual and has not been predicted before,
we increment the number of sucesses by one and increment our score by the number
of successes divided by k. Then, we return our final score divided by the number
of relevant documents (i.e. the length of actual).
apk will return NaN if length(actual) equals 0.
See Also
Examples
actual <- c('a', 'b', 'd')
predicted <- c('b', 'c', 'a', 'e', 'f')
apk(3, actual, predicted)