(flet ((compute-new-rank (document)
         (loop for neighbor in (graph-neighbors document)
               sum (/ (* damping (rank neighbor) (document-similarity document neighbor))
                      (graph-neighbor-edge-sum neighbor)))))
  (block convergence
    (dotimes (i limit)
      (dolist (document documents)
        (let ((old-rank (rank document))
              (new-rank (compute-new-rank document)))
          (setf (rank document) new-rank)
          (when (convergedp old-rank new-rank)
            (return-from convergence t)))))))