Migrate FloydWarshall Algorithm

[clue]

Migrate graphp/graph#71 (refs graphp/graph#119)

[InterLinked1]

Is this still being 'migrated' from somewhere or is the idea to write something new here?

[clue]

I still think that this feature makes perfect sense 👍 However, there are currently no immediate plans to build this from my end (no demand at the moment and more important outstanding issues currently), but I would be really happy to accept PRs 👍

(If you need this for a commercial project and if you want to help sponsor this feature, feel free to reach out and send me an email)

[InterLinked1]

@clue

Well, as you may have guessed, I am using some of these awesome libraries, though not commercially. Figured out the use; stuff eventually, but it looks like it's the older code - though it seems to have the features I need for now, so I guess it doesn't matter much.

I'm not really good with Git, and I don't use it myself, but I started trying to approach this earlier today, following the pseudocode on Wikipedia... don't think this was covered back in my Intro Algorithms course... I got as far as this - not sure it's much help, though:

function floydWarshallWithPathReconstruction($g, $n) {
	$dist = array_fill(0, $n, array_fill(0, $n, INF)); # initialize n*n 2D array with positive infinity
	$next = array_fill(0, $n, array_fill(0, $n, null)); # initialize n*n 2D array with null
	foreach ($g->getEdges() as $edge) {
		$vertices = $edge->getVertices();
		$u = null;
		$v = null;
		foreach ($vertices as $vert) {
			if ($u === null) {
				$u = $vert;
			} else {
				$v = $vert;
			}
		}
		$uID = $u->getAttribute('id');
		$vID = $v->getAttribute('id');
		$dist[$uID][$vID] = 1; // weight
		$next[$uID][$vID] = $v;
	}
	foreach ($g->getVertices() as $v) {
		$vID = $v->getAttribute('id');
		$dist[$vID][$vID] = 0;
		$next[$vID][$vID] = $v;
	}
	for ($k = 1; $k <= $n; $k++) {
		for ($i = 1; $i < $n; $i++) {
			// unfinished # https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm#Path_reconstruction
		}
	}
} 

I stopped here because the way $k and $i are defined, it expects them to be sequential, but the IDs as I was using them in my program are database IDs, and not necessarily sequential, and I was out of brainpower at this point to come up with an immediate workaround to this.

As a side note, I found the PageRank.php file in an abandoned pull request and downloaded that for my own project. Works great. Not sure why it says it 'failed' but I haven't had any issues with it.