[pgrouting-users] pgr_createTopology

[Stephen Mather]

I don't know if I did this correctly, but:

https://github.com/pgRouting/pgrouting/pull/221



On Sat, Nov 30, 2013 at 4:43 PM, Stephen Mather
<stephen at smathermather.com>wrote:

> Done.  Issue #220 <https://github.com/pgRouting/pgrouting/issues/220>.
>
> Thanks,
> Best,
> Steve
>
>
> On Sat, Nov 30, 2013 at 2:52 PM, Stephen Mather <stephen at smathermather.com
> > wrote:
>
>> Cool, I'll write a ticket.  It would be mostly useful in the case of e.g.
>> tutorial development.
>>
>> Best,
>> Steve
>>
>>
>> On Sat, Nov 30, 2013 at 2:46 PM, Stephen Woodbridge <
>> woodbri at swoodbridge.com> wrote:
>>
>>> On 11/30/2013 2:18 PM, Stephen Mather wrote:
>>>
>>>> Is pgr_createTopology deterministic in how it numbers nodes in a built
>>>> topology?
>>>>
>>>
>>> Stephen,
>>>
>>> What do you mean by this?
>>>
>>> If you build a topology on the same edge table twice, do we guarantee
>>> that the nodes numbers will be identical?
>>>
>>> I think the answer is NO, on line:303 of src/common/sql/pgrouting_topology.sql
>>> there is no "order by" clause. This would need to be added to make it
>>> deterministic because relational set theory does not guarantee order of
>>> records in a query without explicitly including and "order by" clause.
>>>
>>> Write a bug if you think this is needed and state why.
>>>
>>> Thanks,
>>>   -Steve
>>> _______________________________________________
>>> Pgrouting-users mailing list
>>> Pgrouting-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
>>>
>>
>>
>
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