R/seqLLCP.R

In TraMineR: Trajectory Miner: a Sequence Analysis Toolkit

# TraMineR 2, Pierre-Alexandre Fonta (2017):
# not deleted because it used in the JSS article

## ==================================================
## Calculates the Length of the Longest Common Prefix
## ==================================================

seqLLCP <- function(seq1, seq2) {
  if (!inherits(seq1, "stslist") | !inherits(seq2, "stslist")) {
    stop(" [!] sequences must be sequence objects")
  }
  a1 <- alphabet(seq1)
  a2 <- alphabet(seq2)
  if (length(a1) != length(a2) || any(a1 != a2)) {
    stop(" [!] The alphabet of both sequences have to be same.")
  }
  l1 <- seqlength(seq1)
  l2 <- seqlength(seq2)
  result <- .C(C_cLCP, as.integer(seq1), as.integer(seq2), as.double(c(l1, l2)),
    result = as.integer(0))$result
  return(result)
}