# What is the computational complexity of the SOM algorithm?

Assuming $m$ observations, $n$ features and $k$ nodes in the self organizing map, what is the complexity of the classic SOM algorithm? What would be the complexity of an ensemble of SOMs, where each SOM has a different number of nodes?

$$T = O(NC) = O(S^2)$$ where $T$ is the computation time, $N$ is the input vector size and $C$ is the number of document presentation cycles. $S$ represents the size of the sample.
This site seems to agree with $O(S^2)$.