[pgrouting-users] TSP - the same source and destination point

[Stephen Woodbridge]

On 3/5/2012 1:43 PM, Dariusz Górski wrote:
> If I do not include the start node in the list of stops, I'll get an error:
> " The connection to the server was lost. Attempting reset: Failed."

Ok, that is not good. Please write a bug ticket for this and a separate 
bug for the fact that it does not create a loop.

In the short term you can work around the loop problem knowing that you 
do not have a closed loop and issuing a separate request from the last 
point to the start point, but this should not be required in my opinion.

> I'm using Ubuntu Server 11.10, PostgreSQL 9.1.3, Postgis 1.5.3,
> pgrouting 1.05 with patch
> https://github.com/sanak/pgrouting/commit/6ec1672f79f7070c60fb6095342d7d0b55cf2659
>
>
> Inside TSP warappers I've changed "tsp_test" to " ' ||
> quote_ident(geom_table) || ' " in order to get them to work.

Please write this up as another bug. Hopefully if we have tickets on 
this stuff we can clean up a lot of these issues in the next release 
when ever that happens.

Thanks,
   -Steve

> Darek
>
> W dniu 2012-03-05 19:03, Stephen Woodbridge pisze:
>> What happens if you do not include the the start node in the list of
>> stops? For example:
>>
>> SELECT * FROM tsp_dijkstra('ways','552,169,784,1567,314',272);
>>
>> I have not used this function in pgRouting so I don't know what to
>> expect.
>>
>> -Steve
>>
>> On 3/5/2012 12:56 PM, Dariusz Górski wrote:
>>> W dniu 2012-03-05 15:15, Stephen Woodbridge pisze:
>>>> On 3/5/2012 6:00 AM, Dariusz Gorski wrote:
>>>>> Hello List,
>>>>>
>>>>> First of all I'd like to say thanks to the pgrouting Team for this
>>>>> great project.
>>>>>
>>>>> I've build pgrouting with patch:
>>>>> https://github.com/pgRouting/pgrouting/pull/49
>>>>>
>>>>> It works fine, but only in case when source and destination are
>>>>> different points.
>>>>>
>>>>> My aim is to solve TSP problem, when start and end point are the same.
>>>>>
>>>>> Any help would be appreciated.
>>>>
>>>> The patch was for specifying a separate end point. But according to
>>>> the thread on the link above, just leave off the last parameter and it
>>>> should work as before. where you give it a list of ids that you want
>>>> it to visit and the source_id for the start which is also the end.
>>>>
>>>> -Steve
>>>> _______________________________________________
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>>>> Pgrouting-users at lists.osgeo.org
>>>> <mailto:Pgrouting-users at lists.osgeo.org>
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>>>>
>>> Steve, thanks for your reply.
>>> I've tried it before, but even when I use standard TSP functions,
>>> e.g. SELECT * FROM tsp_dijkstra('ways','552,272,169,784,1567,314',272);
>>> I don't get the loops (attached image).
>>> This is the reason why I thought that in TSP functions only starting
>>> point is fixed, but endpoint calculates TSP solver.
>>> According to your hint, where source = destination, I would expect to
>>> receive loop.
>>> In my case it does not work in this way.
>>> What am I doing wrong or what am I missing?
>>>
>>> Darek
>>>
>>>
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>>> Pgrouting-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
>>
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