prune {sbo} | R Documentation |
Prune k-gram objects
Description
Prune M
-gram frequency tables or Stupid Back-Off prediction tables for
an M
-gram model to a smaller order N
.
Usage
prune(object, N, ...)
## S3 method for class 'sbo_kgram_freqs'
prune(object, N, ...)
## S3 method for class 'sbo_predtable'
prune(object, N, ...)
Arguments
object |
A |
N |
a length one positive integer. N-gram order of the new object. |
... |
further arguments passed to or from other methods. |
Details
This generic function provides a helper to prune M-gram frequency
tables or M-gram models, represented by sbo_kgram_freqs
and
sbo_predtable
objects respectively, to objects of a smaller N-gram
order, N < M. For k-gram frequency objects, frequency tables for
k > N are simply dropped. For sbo_predtable
's, the predictions coming
from the nested N-gram model are instead retained. In both cases, all other
other attributes besides k-gram order (such as the corpus preprocessing
function, or the lambda
penalty in Stupid Back-Off training) are left
unchanged.
Value
an object of the same class of the input object
.
Author(s)
Valerio Gherardi
Examples
# Drop k-gram frequencies for k > 2
freqs <- twitter_freqs
summary(freqs)
freqs <- prune(freqs, N = 2)
summary(freqs)
# Extract a 2-gram model from a larger 3-gram model
pt <- twitter_predtable
summary(pt)
pt <- prune(pt, N = 2)
summary(pt)