In function:

   static int weighted_levdist

There is a block of code: 

   118          /* if we already used up one string, then
   119        the result is the length of the other */
   120          if(*s1=='\0') return strlen(s2);
   121          if(*s2=='\0') return strlen(s1);
 
This is correct for unweighted, but not weighted Levenshtein.

The value on line 120 should be multiplied by
cost_ins, and the value on line 121 should be multiplied
by cost_del.

Steven Bird <sb@ldc.upenn.edu>
http://www.ldc.upenn.edu/sb/