[pgrouting-users] pgr_createTopology

[Stephen Mather]

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
>> _______________________________________________
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>>
>
>
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