Heuristics are algorithms and algorithms don't have to give definite answers.
No, that's just not true. A heuristic is a procedure that gives no guarantee of a correct answer. An algorithm is a deterministic procedure that does guarantee a correct answer. Heuristics are very useful in making difficult decisions that don't have definite answers, but they are not algorithms.
Re:When Truth Survives Free Speech
by ramidarigaz on Monday December 12, 2011 @05:34PM
(#3345325)
Erm. Algorithms aren't necessarily deterministic. http://en.wikipedia.org/wiki/Nondeterministic_algorithm
Primality testing is a very good example of a useful algorithm that gives an answer that is probably correct.
Re:When Truth Survives Free Speech
by byrneseyeview on Tuesday December 13, 2011 @09:49PM
(#3350353)
Thank you for the correction. I'd been using terminology ineffectively. The way I was taught it was:
- An algorithm is a step-by-step process for transforming any valid input into a specific valid output. - A heuristic is a process that brings you closer to something that looks like an answer, but does not necessarily find the best possible answer.
And the analogy breaks down here because the online ecosystem adapts very fast. It would work if there was some sort of gene that led to premature births plus high Apgar scores (the equivalent of a malicious website that ranks well).
That's why search is so tough: search engines and gaming have coevolved to the point that in plenty of areas, search quality would go down if people weren't trying to game the algorithm.