Compute tree similarity

Compute tree similarity

Usage

K2(t1, t2, verbose = FALSE)

Arguments

t1

A TreeHarp object.

t2

A TreeHarp object.

verbose

A logical value, indicating if the output should be verbose.

Value

An integer, that counts the number of sub-trees in common between the two trees. Please see the reference papers for more information.

Details

As far as possible, this function tries to do things recursively. It sets up a n x m matrix and fills up as much as it can. Then it uses recursive relationships to fill in the rest. When it cannot, it uses generate_all_subtrees to generate and count common subtrees.

References

1. Convolution kernels for natural language, M Collins and N Duffy, Advances in neural information processing systems, 2002.

2. Convolution kernels on discrete structures, D Haussler, Technical report, Department of Computer Science, UC Santa Cruz, 1999.

Examples

tree1 <- TreeHarp(quote(x <- 1), TRUE)
tree2 <- TreeHarp(quote(y <- 1), TRUE)
K2(tree1, tree2, TRUE)
#> Filling up matrix.
#> 1 entries remaining.
#> [1] 3