On Tue, Oct 6, 2009 at 8:38 PM, Matthew Byrne <matt...@hairybrain.co.uk> wrote: > > The following bug has been logged online: > > Bug reference: 5098 > Logged by: Matthew Byrne > Email address: matt...@hairybrain.co.uk > PostgreSQL version: 8.4.1 > Operating system: Linux x86_64 (Ubuntu 9.04) > Description: Levenshtein with costs is broken > Details: > > The Levenshtein with costs function in the fuzzystrmatch module is coded > incorrectly. The initial values in the distance matrix are set up as 0, 1, > 2 etc. when they should be 0, deletion_cost, (2 * deletion_cost)... and 0, > insertion_cost, (2 * insertion_cost) etc. respectively. This causes the > function to return incorrect values, e.g.: > > SELECT LEVENSHTEIN('ABC', 'XABC', 100, 100, 100) > > returns 1 (the correct answer is 100). > > To fix this, make the following changes to fuzzystrmatch.c: > > Change line 244 from > prev[i] = i; > to > prev[i] = i * del_c; > > and change line 255 from > curr[0] = j; > to > curr[0] = j * ins_c;
FYI, this was fixed in 8.4.2. ...Robert -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs