[SCIP] Difference between SCIPsolve and SCIPsolveConcurrent

[Guillerme Duvillié]

Dear all,

I'm a little bit puzzled about the difference between SCIPsolve and
SCIPsolveConcurrent. Based on what I understood, SCIPsolveConcurrent was
some sort of parallel implementation of SCIPsolve.

If this is the case, I experience something that seems weird to me. I'm
implementing branch and price algorithm for some special cases of
multidimensional affectation problems. When I use SCIPsolve to solve the
pricing problem, the resolution is really slow, the pricing is solved
over and over again and the general solution gets stuck to the
provided initial solution even after one hour of computations. On the
other hand, using SCIPsolveConcurrent returns the following error after
few miliseconds (and two pricing iterations):

[src/scip/solve.c:4503] ERROR: pricing was aborted, but no branching
could be created!
[src/scip/solve.c:4933] ERROR: Error <-10> in function call
[src/scip/scip.c:16231] ERROR: Error <-10> in function call
[src/scip/scipshell.c:100] ERROR: Error <-10> in function call
[src/scip/scipshell.c:392] ERROR: Error <-10> in function call
[src/cmain.c:162] ERROR: Error <-10> in function call
SCIP Error (-10): method returned an invalid result code

Snce I'm a SCIP beginner, the probability that I made a mistake in my
code is close to 1, but I cannot understand why switching from one
solving method to another returns such different answer.

Thank you in advance.

-- 
Guillerme DUVILLIÉ
Post Doc

guillerme.duvillie at ulb.ac.be
Université Libre de Bruxelles - Faculté des Sciences
GOM Team
Computer Science Department


http://cv.duvillie.eu
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