[pgrouting-dev] Finally getting back to integrating your TRSP improvements

[Ashraf Hossain]

Dear Steve,
I am out of town in village, I will come back to you soon with my thoughts.

Regards
Roni


On Sun, Apr 13, 2014 at 6:28 AM, Stephen Woodbridge <woodbri at swoodbridge.com
> wrote:

> Hi Roni,
>
> I hope you and your family are doing well.
> I am well but have been very busy. I'm between some contracts at the
> moment and I am looking at the TRSP improvements you did quite a ways back
> to add the reverse cost and routing from nodes A-B-C-...
>
> Looking at multi_dijkstra it seems that I should be able to mimic that
> code based on how you clean up after each route A-B to restart for B-C and
> create a similar function that computes one to many destinations, A-B, A-C,
> A-D, etc.
>
> What do you think?
>
> So for integrating this code, I probably need to implement a family of
> additional functions like:
>
>
> Existing functions:
>
> pgr_trsp(text, integer, integer, boolean, boolean)
> -- node to node
>
> pgr_trsp(text, integer, integer, boolean, boolean, text)
> -- node to node with restrictions
>
> pgr_trsp(text, integer, double precision, integer, double precision,
> boolean, boolean)
> -- edge to edge
>
> pgr_trsp(text, integer, double precision, integer, double precision,
> boolean, boolean, text)
> -- edge to edge with restrictions
>
> pgr_trsp(text, integer[], boolean, boolean, text)
> -- array of nodes **this gets changed to use new code (1)**
>
> pgr_trsp(text, integer[], float8[], boolean, boolean, text)
> -- array of edges **this gets changed to use new code (2)**
>
> (1) should plug directly into your code. I currently do this in C by
> calling your old code multiple times, but it will be more efficient to
> change this to call multi_dijkstra because we only build the graph once.
>
> (2) I currently do this in C by making multiple calls to your old code.
> The multi_dijkstra only accepts nodes, not edges, so I'll look at making a
> version that can be called by edges. Unless you want to do that :)
>
> Then I think I would like to add a new argument to (1) and (2) above
> "boolean onetomany" and if it is true then we compute A-B, A-C, A-D, ...
> and if it is false it will compute A-B-C-...
>
> I'll have to think about how to return the results, but that should not be
> too hard.
>
> TODO:
>
> 1. create function to support multi_dijkstra with edges
> 2. create new function onetomany_dijkstra for nodes
> 3. create new function onetomany_dijkstra for edges
> 4. update C code wrappers to support the above
> 5. develop test cases
> 6. write the documentation
> 7. check it in
>
> Ok that is a bunch of work! Maybe I'll start with just getting (1) done so
> it calls your new code, and write a test case for that. Then tackle the
> rest.
>
> Thoughts?
>
> -Steve
>
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