[Scip] probing in pricer in scip 1.2 and probing in presolver

[Frank Hennig]

Hi,

 

a)

I have trouble with the lower bound when I use scip 1.2. with my
Branch-and-Price.

 

Maybe this is due to probing in my pricer.

 

In the last version I took out SCIP_CALL(
SCIPnodeUpdateLowerboundLP(tree->focusnode, set, stat, lp) ); in
SCIPtreeEndProbing() in file src/scip/tree.c.

 

This fixed some problems.

 

Do you think this can be done without problems in scip 1.2., too?

 

 

b)

It is not allowed to call SCIPsolveProbingLP() in a presolver. However,
if I do so I can speed my computations a lot. I wonder if doing so can
cause other troubles I do not know about.

Faster computations can also go back on identifying solutions during the
presolver. I also call SCIPpropagateProbing. 

 

Is it possible that solution come from propagation even if solving the
LP does not work? If yes, how do they get in my solution pool?

I only see problems in debug mode. In debug mode SCIPsolveProbingLP
seems to return -8. In usual mode this seems not to be the case.

 

 

Can you help?

 

 

Regards, Frank   

 

 

 

________________________________________________________

 

Frank Hennig  -  Naval Architect, PhD Candidate

 

Department of Industrial Economics and Technology Management

Norwegian University of Science and Technology

Alfred Getz veg 3

NO-7491 Trondheim, Norway

 

Phone:   +49 30 314 23 598

Email:      frank.hennig at iot.ntnu.no

 

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