[SCIP] Custom branching -- catching an assert

[Stefan Vigerske]

Hi,

There can be problems if you define NDEBUG for your code that includes 
SCIP headers and link against a SCIP library that has been build with 
NDEBUG not defined (e.g., OPT=dbg). Some SCIP structs that your code 
will try to access to directly will then not match the structs that are 
used by code inside the SCIP library.
This should be fixed in the next bugfix release.

Best,
Stefan

PS: I cannot imagine that -DNDEBUG will disable anything in CPLEX 
(unless you build CPLEX from source, too).

On 6/23/20 9:27 AM, Schrotenboer, Albert wrote:
> Dear Gerald (and others)
> 
> Thank you for the clarification (months ago). I've been implementing it in
> the way you suggested, everything seems ok, but then I encountered some
> weird behaviour.
> 
> I compile the code  in normal mode -> seems to work fine
> I compile the code in DBG=opt mode -> seems to work fine
> 
> In my program I also have some upper bounds that use plain CPLEX, so I
> decided to use the flag -DNDEBUG while compiling, which is (as far as I
> know) disabling CPLEX debug mode
> 
> When I now compile my code in DBG=opt mode with the -DNDEBUG flag, I catch
> an assert somewhere within scip:
> JRP: src/scip/tree.c:1214: SCIPnodePropagateAgain: Assertion `node != NULL'
> failed.
> 
> Do you maybe know if this flag is the cause of any unspecified behavior? Of
> course, it is a bit weird to use debug mode and to tell at the same time to
> not debug (via the flag), but I want to make sure things are correct.
> 
> 
> Kind regards,
> Albert
> 
> 
> On Thu, Jan 9, 2020 at 12:46 PM Gerald Gamrath <gamrath at zib.de> wrote:
> 
>> Dear Albert,
>>
>> changing the upper bound to 0 to enforce your decision is correct.
>> However, your consactive method should only mark the constraint to be
>> repropagated; afterwards, propagation will be called where you should
>> adjust the bounds. Since the bound is only changed at the current node,
>> SCIP will automatically undo this when the current subtree is left and
>> re-install the bound when it is re-entered. In the latter case, you thus
>> only need to propagate variables added in the meantime.
>>
>> For more details, see
>> https://scip.zib.de/doc-6.0.2/html/FAQ.php#pricerandnodedata or have a
>> look at the binpacking example.
>>
>> Best,
>> Gerald
>>
>> Am 09.01.20 um 10:45 schrieb Schrotenboer, Albert:
>>
>> Dear SCIP Community,
>>
>> I am solving a basic VRP with branch & price, and have a question
>> regarding a branching rule I've implemented (Actually, I forgot how to do
>> it...) I branch on x_{ij} arcs, which I identify with my branchrule object.
>> To handle this information down the b&b tree, I use a constraint handler
>> with the following virtual methods implemented:
>>
>> SCIP_DECL_CONSTRANS(ObjConshdlrOwn::scip_trans)
>>        To transform the info, nothing special
>> SCIP_DECL_CONSACTIVE(ObjConshdlrOwn::scip_active)
>>        Here I search which of my generated routes should be fixed to zero
>> corresponding to my branching information. (I also do the appropriate
>> adaptations in my pricing based on the branching). I fix my variables by
>> the following routines:
>>
>> if (SCIPvarGetUbLocal(var) > 0.01)
>>        SCIP_CALL(SCIPchgVarUb(scip, (*d_varConsInfo).v_path[r].d_var, 0.0)
>> );
>>
>> This all works nicely (when I do not run in debug mode). When I run in
>> Debug mode, however, an assert is collapsing when SCIP alters the path of
>> the tree (when it backtracks a few nodes), saying that:
>> JRP: src/scip/tree.c:1803: SCIPnodeAddBoundinfer: Assertion
>> `(SCIP_NODETYPE)node->nodetype == SCIP_NODETYPE_FOCUSNODE ||
>> (SCIP_NODETYPE)node->nodetype == SCIP_NODETYPE_PROBINGNODE ||
>> (SCIP_NODETYPE)node->nodetype == SCIP_NODETYPE_CHILD ||
>> (SCIP_NODETYPE)node->nodetype == SCIP_NODETYPE_REFOCUSNODE || node->depth
>> == 0' failed.
>>
>> My question is, therefore, the following: Is changing the UB to enforce
>> variables to 0 the correct way to go? In addition, am I required to
>> implement the deactive virtual method as well, to change the upper bounds
>> back to what they were?
>>
>> Kind regards,
>> Albert
>>
>> --
>>
>> Albert Schrotenboer
>>
>> Postdoctoral Researcher
>>
>> Faculty of Economics and Business
>>
>> University of Groningen
>>
>> P.O. Box 800, 9700 AV Groningen
>>
>> _______________________________________________
>> Scip mailing listScip at zib.dehttps://listserv.zib.de/mailman/listinfo/scip
>>
>>
>>
> 
> 
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