[Scip] Some basic questions

[Mehmet Pancaroğlu]

Hi everyone,

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I am trying to implement branch-and-price algorithm on my location-routing problem. So far, i have implemented my algorithm for one candidate location. I feel more comfortable when i used existing codes to improve. That's why I used VRP example to improve it and i know i need to extend pricing part where i can find tours for each candidate location. I am not an experienced coder and I am just afraid of getting errors :) 

Here are some information about my algorithm:
1. I am not using tailored branching rule (basically branching on location and arc variables, yes i write arc variables on master problem in order to escape writing branching decision for now, at least)
2. I am solving exact problem in pricing part, heuristic will be considered. ( only small instances can be handled now)

Solution process is a black box at that time. I need to discover it to improve my algorithm.

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I want to learn:
1. which constraints are added in each node. It is same for pricing problem. Somehow, i can get which routes are added in a node, however, i have no idea about in which node they are generated. 
2. any way to visualise tree ( i read there is something vcb, however i didnt understand how to install it) or suggestion (i.e. output format) to get relevant info.
3. how to branch on location variables first ( question came to my mind now, i did not search for it)
4. Does a generated route can be used in another node which is not a subsequent node of route's origin node or does it required to be generated again? It doesn't seem so but i want to ask it.
5. Any idea to improve my algorithm.

Thank you in advance


Mehmet