Hi Harald, I think the operations in the case with zeroes are not random, but a cyclic permutation of the rows, which allows to reuse most of the previously computed minors. I haven't read a complete description of the algorithm, but if cyclic permutations are always enough in the case with zeroes, they should just add at most a quadratic term to the computation time.
Cheers J On 4 Aug, 16:20, Harald Schilly <[email protected]> wrote: > On 4 Aug., 16:05, Robert Miller <[email protected]> wrote: > > >http://en.wikipedia.org/wiki/Dodgson_condensation > > Nice, never heard of, but how does the case with zeros work? In the > example with zeros, C has zeros and then they do some random > operations (?) on the initial matrix to get rid of them. That sounds > bad. Rather, if this is really O(n^3), this algorithm should be called > first and if there happens to be a zero case, stop it and do the > O(n^4) routine. > > H -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
