diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/fuzzystrmatch.sgml | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/doc/src/sgml/fuzzystrmatch.sgml b/doc/src/sgml/fuzzystrmatch.sgml index 69777e49358..01b6e127ba6 100644 --- a/doc/src/sgml/fuzzystrmatch.sgml +++ b/doc/src/sgml/fuzzystrmatch.sgml @@ -84,6 +84,8 @@ SELECT * FROM s WHERE difference(s.nm, 'john') > 2; <synopsis> levenshtein(text source, text target, int ins_cost, int del_cost, int sub_cost) returns int levenshtein(text source, text target) returns int +levenshtein_less_equal(text source, text target, int ins_cost, int del_cost, int sub_cost, int max_d) returns int +levenshtein_less_equal(text source, text target, int max_d) returns int </synopsis> <para> @@ -92,6 +94,11 @@ levenshtein(text source, text target) returns int specify how much to charge for a character insertion, deletion, or substitution, respectively. You can omit the cost parameters, as in the second version of the function; in that case they all default to 1. + <literal>levenshtein_less_equal</literal> is accelerated version of + levenshtein functon for low values of distance. If actual distance + is less or equal then max_d, then <literal>levenshtein_less_equal</literal> + returns accurate value of it. Otherwise this function returns value + which is greater than max_d. </para> <para> @@ -110,6 +117,18 @@ test=# SELECT levenshtein('GUMBO', 'GAMBOL', 2,1,1); ------------- 3 (1 row) + +test=# SELECT levenshtein_less_equal('extensive', 'exhaustive',2); + levenshtein_less_equal +------------------------ + 3 +(1 row) + +test=# SELECT levenshtein_less_equal('extensive', 'exhaustive',4); + levenshtein_less_equal +------------------------ + 4 +(1 row) </screen> </sect2> |