inst/examples/calc-perplexity.R

In wordpredictor: Develop Text Prediction Models Based on N-Grams

# Start of environment setup code
# The level of detail in the information messages
ve <- 2
# The name of the folder that will contain all the files. It will be created in
# the current directory. NULL implies tempdir will be used.
fn <- NULL
# The required files. They are default files that are part of the package
rf <- c("def-model.RDS")
# An object of class EnvManager is created
em <- EnvManager$new(ve = ve, rp = "./")
# The required files are downloaded
ed <- em$setup_env(rf, fn)
# End of environment setup code

# The model file name
mfn <- paste0(ed, "/def-model.RDS")
# ModelPredictor class object is created
mp <- ModelPredictor$new(mf = mfn, ve = ve)
# The sentence whoose Perplexity is to be calculated
l <- "last year at this time i was preparing for a trip to rome"
# The line is split in to words
w <- strsplit(l, " ")[[1]]
# The Perplexity of the sentence is calculated
p <- mp$calc_perplexity(w)
# The sentence Perplexity is printed
print(p)

# The test environment is removed. Comment the below line, so the files
# generated by the function can be viewed
em$td_env()