[SCIP] Problem with lazy bounds

[Ngô Lan]

Hi all,


I am implementing branch and price in which I set the binary decision variables of master problem to have lazy bound of 1 as suggested on SCIP's FAQ. After running for a while, I get this assertion error:


scipoptsuite-6.0.2/scip/src/scip/lp.c:12184: updateLazyBounds: Assertion `lp->divinglazyapplied || SCIPsetIsLT(set, col->ub, col->lazyub) || (col->flushedub == SCIPlpiInfinity(lp->lpi))' failed.


and here is the backtrace


#0  0x00007ffff9d25428 in __GI_raise (sig=sig at entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff9d2702a in __GI_abort () at abort.c:89
#2  0x00007ffff9d1dbd7 in __assert_fail_base (fmt=<optimized out>,
    assertion=assertion at entry=0x7ffffd93c4a0 "lp->divinglazyapplied || SCIPsetIsLT(set, col->ub, col->lazyub) || (col->flushedub == SCIPlpiInfinity(lp->lpi))",
    file=file at entry=0x7ffffd937000 "/mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/lp.c",
    line=line at entry=12184, function=function at entry=0x7ffffd93fcc0 <__PRETTY_FUNCTION__.22071> "updateLazyBounds")
    at assert.c:92
#3  0x00007ffff9d1dc82 in __GI___assert_fail (
    assertion=0x7ffffd93c4a0 "lp->divinglazyapplied || SCIPsetIsLT(set, col->ub, col->lazyub) || (col->flushedub == SCIPlpiInfinity(lp->lpi))", file=0x7ffffd937000 "/mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/lp.c",
    line=12184, function=0x7ffffd93fcc0 <__PRETTY_FUNCTION__.22071> "updateLazyBounds") at assert.c:101
#4  0x00007ffffbe3caab in updateLazyBounds (lp=0x61600000c980, set=0x61d00001d680)
    at /mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/lp.c:12183
#5  0x00007ffffbe3d087 in SCIPlpSolveAndEval (lp=0x61600000c980, set=0x61d00001d680, messagehdlr=0x608000005620,
    blkmem=0x625000007900, stat=0x61b00001ea80, eventqueue=0x60300001fe40, eventfilter=0x61900001bc80,
    prob=0x611000018280, itlim=-1, limitresolveiters=0, aging=0, keepsol=0, lperror=0x7ffffffed518)
    at /mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/lp.c:12277
#6  0x00007ffffc007153 in SCIPsolveDiveLP (scip=0x611000002ac0, itlim=-1, lperror=0x7ffffffed518, cutoff=0x0)
    at /mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/scip_lp.c:2519
#7  0x00007ffffbb11c90 in heurExecIntshifting (scip=0x611000002ac0, heur=0x60f0000071b0, heurtiming=40,
    nodeinfeasible=0, result=0x7ffffffed6f8)
    at /mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/heur_intshifting.c:1100
#8  0x00007ffffbdeb301 in SCIPheurExec (heur=0x60f0000071b0, set=0x61d00001d680, primal=0x60c00001a500, depth=11,
    lpstateforkdepth=10, heurtiming=40, nodeinfeasible=0, ndelayedheurs=0x7ffffffed6fc, result=0x7ffffffed6f8)
    at /mnt/c/Users/hp/Documents/GitHub/scipoptsuite-6.0.2/scip/src/scip/heur.c:1116
#9  0x00007ffffc0b35d4 in SCIPprimalHeuristics (set=0x61d00001d680, stat=0x61b00001ea80, prob=0x611000018280,
    primal=0x60c00001a500, tree=0x61300000d240, lp=0x61600000c980, nextnode=0x631000723498, heurtiming=40,
    nodeinfeasible=0, foundsol=0x7ffffffed86c, unbounded=0x7ffffffed864)


I have read several questions in the mailing list regarding the same errors but I can't really find any solutions for it. Why does the error occur and what should I do? Gerald asked for col->flushedub value in one of the thread so mine is either 100000000000000000000 or 0 and it was 0 when the error occurred.


Thank you for your help.


Best,

Lan
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