diameter

diameter column1 column2

get the graph diameter (also known as max path length or hop size) of spanning-trees, from space-separated formats similar to output of the irc LINKS command

column1 and column2 are the column indices to look at for node names. note that these start from 0, contrary to other utilities such as awk and cut.

example

cargo run -Fbin 3 4 <<EOF
:fox. 364 xfnwtest sparrow. maned.wolf :2 bird
:fox. 364 xfnwtest feesh. otter. :2 wiggle wiggle
:fox. 364 xfnwtest services. fox. :1 Atheme IRC Services
:fox. 364 xfnwtest maned.wolf fox. :1 legs
:fox. 364 xfnwtest otter. fox. :1 squeak squeak
:fox. 364 xfnwtest fox. fox. :0 solanum fox server
EOF

results in: 4 hops between feesh. and sparrow.

bugs

• this was designed to handle a spanning-tree (trees with no loops permitted, ensuring a single path to any node) only, since this makes finding the longest path a lot easier. depth-first-search cannot handle loops, so we silently ignore already visited nodes to prevent infinite recursion. as the internal representation is not fully sorted, this will result in inconsistant and incorrect results depending on the input order.
• unreachable nodes will be ignored when searching. it currently starts from the first inputted node, though this should not be depended upon.