[Cartoweb-users] dijkstra

[Sylvain Pasche]

Hi Raphael,

There is a constraint on the identifiers which can be used as vertex identifier with pgdijkstra:

They should be numbers which should be less that the total number of nodes you have in you graph (plus a small value).
(This constrains exists for performance reasons).

To get around this constrain, there is the create_graph_tables() function you can use (See the README for an example).

This "issue" should be better documented, I admit.

Regards,

Sylvain

Le mardi 10 janvier 2006 à 15:10 +0100, Eggenschwiler Raphael a écrit :
> Hi everyone !
> 
> I try to use this pgdijkstra on my data with :
> 
> SELECT arc_num_nod_src as "source",arc_num as "id",arc_num_nod_des as
> "target",arc_cost as "cost" FROM TAB_ARC;
> 
> source   id    target    cost
> 0         6259    4769    0
> 4769    6260    4770    0
> 4770    6261    4771    0
> 4771    6262    4772    0
> 4772    6263    4773    0
> 0         6264    4775    0 
> 4775    6265    4776    0
> 4776    6266    4777    0
> 4777    6267    4778    0
> 4778    6268    4779    0
> 4779    6269    4780    0
> 4780    6270    4781    0
> 0         6271    4783    0
> 4783    6272    4784    0 
> 4784    6273    4785    0
> 4785    6274    4786    0
> 4786    6275    4787    0
> 4787    6276    4788    0
> 4788    6277    4789    0
> 4789    6278    4790    0
> 0         6279    4792    0
> 4792    6280    4793    0 
> 
> But when I try this one :
> 
> select * from shortest_path('SELECT arc_num_nod_src as
> "source",arc_num as "id",arc_num_nod_des as "target",arc_cost as
> "cost" FROM TAB_ARC',4769,4770,false,false);
> 
> I become this message :
> 
> ERROR:  Error computing path: Source vertex not found
> 
> Can someone help me ??
> 
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