A new algorithm of Graph Isomorphism is invented by PCT/CN2020/134861, roughly speaking time complexity $\leqslant5n^2$ except for regular graph, automorphism group can be known as by-product. Peer reviewed paper can be downloaded from www.getpaperfree.com by search "同构", it is written in Chinese.

Except strongly regular graph, all other regular graph's isomorphism can be decided in $O(n^3)$.

After 2 years' hard work, I failed to know what's the worst case for strongly regular graphs, but conjecture : for most of strong regular graphs, it is less than $O(n^5)$.

If you know a good classification of strongly regular graphs or other useful algorithm for them, please answer the question. Thank you!