[Lemon-user] Running Network Simplex in modified versions of the network

[Kovács Péter]

Hi Rodrigo,

First of all, if you would like to remove arcs and/or nodes, then you 
should use the ListDigraph structure instead of SmartDigraph. For more 
information, read the following sections of the LEMON tutorial:
http://lemon.cs.elte.hu/pub/tutorial/a00011.html
http://lemon.cs.elte.hu/pub/tutorial/a00015.html
and the API documentation of the ListDigraph class:
http://lemon.cs.elte.hu/pub/doc/1.3/a00235.html

Anyway, min-cost flow algorithms in LEMON use special internal graph 
representations, so there is no considerable performance effect of the 
choice of your graph structure. It is copied into the algorithm-specific 
representation as an initialization step.

For the iterative usage of NetworkSimplex, all you have to do is calling 
its reset() function before consecutive run() calls. For more 
information, see the API documentation:
http://lemon.cs.elte.hu/pub/doc/1.3/a00269.html#a88086127469093e19a9a024bbf60c360

Best regards,
Peter



On 2014.06.10. 0:31, RODRIGO MESA ARANGO wrote:
> Dear Lemon Users,
>
> I'm learning Lemon to develop an algorithm. I'm planning to:
> 1. Set original network
> 2. Run min-cost flow algorithm (currently network simplex)
> 3. Modify network based on results (add/remove arcs, modify capacities
> and costs)
> 4. Repeat 2 over modified network up to a stopping criterion
>
> I used a SmartDigraph and could run network simplex but cannot modify
> the network (add/remove/modify arcs) iteratively.
>
> Q1. Can you please suggest me how to modify the network?
> Q2. What digraph structures are better for network simplex (or min-cost
> flow algorithms in general) and how to use them?
>
> Thank you. Have a nice day!
>
> *___Rodrigo Mesa Arango________________________________*
> *       PhD Student* - Transportation Engineering and Infrastructure
> Systems <https://engineering.purdue.edu/CE/Academics/Groups/Transportation>
> ***Research Assistant* - Transportation Engineering and Infrastructure
> Systems <https://engineering.purdue.edu/CE/Academics/Groups/Transportation>*
> *
> ***Email* - rmesaara at purdue.edu
> <mailto:rmesaara at purdue.edu>rmesaa at gmail.com <mailto:rmesaa at gmail.com>
> *Visit my website <http://web.ics.purdue.edu/%7Ermesaara/>*
> "/Three things that never come back; the spent arrow, the spoken word
> and the lost opportunity/." Willam George Plunkett
>
>
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