Bellman-Ford - is number of interations greater than diameter?
In the Bellman–Ford algorithm, after $t$ iterations the array contains, for any two nodes, the minimal walk of length at most $t$ connecting them. Assuming your graph doesn't have negative weights, the shortest walk between any two vertices will be a path, and so its length would be at most the diameter. Therefore there is no need to run the algorithm beyond $d$ iterations.