[pgrouting-dev] K-Shortest Path round-trip pattern question

[Ko Nagase]

Hi list,

I am facing an issue about K-Shortest Path round-trip pattern.

When I specified same source and target ids, then pgr_ksp results are
invalid like this.
==========
sampledata=# SELECT seq, id1 AS route, id2 AS node, id3 AS edge, cost
 FROM pgr_ksp(
   'SELECT id, source, target, cost FROM edge_table',
   1, 1, 4, false
 );
 seq | route | node |    edge     |         cost
-----+-------+------+-------------+-----------------------
   0 |     0 |    1 | -2147483648 | 1.79769313486232e+308
   1 |     0 |    1 |          -1 |                     0
(2 rows)
==========

I think that the results should be as follows,
because in my understanding, K-Shortest Path should support round-trip pattern.
==========
 seq | route | node |    edge     |         cost
-----+-------+------+-------------+-----------------------
   0 |     0 |    1 |           1 |                     1
   1 |     0 |    2 |           1 |                     1
   2 |     0 |    1 |          -1 |                     0
   3 |     1 |    1 |           1 |                     1
   : |     : |    : |           : |                     :
==========

But is my understanding wrong ?
(Shouldn't K-Shortest Path support round-trip case ?)

If my understanding is wrong, does someone know
how to support round-trip case ?


About above pgr_ksp issue, I created the ticket to here.
[pgr_ksp returns invalid one route when source and target are same #287]
https://github.com/pgRouting/pgrouting/issues/287

Regards,

-- 
Ko Nagase (長瀬　興)
Georepublic Japan
mail: nagase at georepublic.co.jp
web: http://georepublic.co.jp