On 6-5-2010 22:37, Michel Fortin wrote: > On 2010-05-05 23:45:50 -0400, Walter Bright <[email protected]> > said: > >> Walter Bright wrote: >>> Alex Makhotin wrote: >>>> It takes ~40 seconds 50% load on the dual core processor(CentOS 5.3 >>>> kernel 2.6.32.4), to get the actual error messages about the >>>> undefined identifier. >>> >>> Definitely there's a problem. >> >> The problem is the spell checker is O(n*n) on the number of characters >> in the undefined identifier. > > That's an algorithm that can't scale then. > > Checking the Levenshtein distance for each known identifier within a > small difference in length would be a better idea. (Clang is said to use > the Levenshtein distance, it probably does something of the sort.) > > http://en.wikipedia.org/wiki/Levenshtein_distance > and especially this line:
# If we are only interested in the distance if it is smaller than a threshold k, then it suffices to compute a diagonal stripe of width 2k+1 in the matrix. In this way, the algorithm can be run in O(kl) time, where l is the length of the shortest string.
