Keccak is mentioned in cns008 (the cryptonight hash description) in two ways: First in section 3 (Scratchpad Initialization) as
Keccak, and another time in section 5 (Result Calculation) as
Keccak-f (the Keccak permutation).
It seems to suggest that the modified state from the original Keccak function is used as the whole input to another unique Keccak calculation, but the change to
Keccak-f makes it seem like there is something special about it.
What is the difference between these two references, if any?