Adding support for non continuous number ranges, and Symmetric distances to the current traveling salesman problem

[dapotts]

The files in the gist dapotts / atspmat.sql add support for

1. Non continuous number ranges in the pgr_tsp. Usage is select seq,id from pgr_mktspret('select source,target,cost from edge5' ,xx); where xx is any node, which does have to be in the range 1-N
2. A function for checking if your distance matrix is valid pgr_checktsparray, takes an distance matrix and check that there are enough values, only zeros are in the leading diagnonal, The value i,j is the same as j,i
3. A method for resolving the Asymmetric salesman problem. Process a a distance matrix where the cost of A-B is not the same as B-A

[woodbri]

Here is a link to Dave's gist: https://gist.github.com/dapotts/6133259 I think some variation of this should be considered from 2.1

[dkastl]

This is nice! Thanks @dapotts ! I think it's good to collect additional functions first as Gists and we can then see what makes sense to include to core pgRouting. Maybe different cases can be unified and generalized then.

"matching.sql" was exactly a case, where some functions were useful for many but they often were too specific and now sometimes users ask where the functions are they used before.