To summarize: multiplication hashes are inferior but when used with the golden ratio derived integer, they are actually superior
To summarize: multiplication hashes are inferior but when used with the golden ratio derived integer, they are actually superior
Poor summary.
Better summary. Fibonacci hashing isn't a great hash function, but it is a really good solution to mapping large integers to small integers. Using it for that doubles the speed of hashing in practice.
Why not just xor all the bits together?
No, plenty of systems use other factors. The golden ratio has some nice properties, but it's not essential.