On 8 May 2009, at 16:56, Mart Sõmermaa wrote:
On Fri, May 8, 2009 at 6:06 PM, Arnaud Delobelle <arnodel@googlemail.com
wrote:
I implemented a unification algorithm that needed multisets to work in O(n^2).
Complexity is a totally different theme and best reserved for extensions. Supporting special-case containers that have various space/speed and best/worst case tradeoffs have been discussed before and the consensus seems to be that supporting them in stdlib is infeasible -- with what I entirely agree. Supporting multiset only for O(n^2) performance would violate that consensus.
You misunderstand me. My task was to implement this algorithm. Multisets were the natural data structure to implement this algorithm. That it was O(n^2) (rather than the exponential complexity of the naive unification algorithm) is an issue attached to the algorithm, not to whether I use multisets or not to implement it. -- Arnaud