[Scip] "SCIProwGetScalarProduct: Assertion `row2->nonlpcolssorted' failed." after adding a cut.

Thu Jan 5 13:58:46 MET 2012

Hi and happy new year to everyone,

I have the following problem.
After adding a cut in a constraint handler with SCIPaddCut, I get the
following error (the added cuts are printed out with SCIPaddRow for
debugging purposes:

...
 15.9s|     1 |     0 |  1445 |     - |  13M|   0 | 138 | 723 |1368 | 723
|1435 |  71 |   1 |   0 | 8.287500e-01 | 1.050000e+00 |  26.70%
 16.3s|     1 |     0 |  1448 |     - |  13M|   0 | 144 | 723 |1368 | 723
|1436 |  72 |   1 |   0 | 8.287500e-01 | 1.050000e+00 |  26.70%
E16.4s|     1 |     0 |  1448 |     - |  13M|   0 | 144 | 723 |1368 | 723
|1436 |  72 |   1 |   0 | 8.287500e-01 | 9.783333e-01 |  18.05%
 16.5s|     1 |     0 |  1448 |     - |  13M|   0 | 144 | 723 |1368 | 723
|1436 |  72 |   1 |   0 | 8.287500e-01 | 9.783333e-01 |  18.05%
 16.9s|     1 |     0 |  1465 |     - |  13M|   0 | 164 | 723 |1368 | 723
|1439 |  75 |   1 |   0 | 8.287500e-01 | 9.783333e-01 |  18.05%
 16.9s|     1 |     2 |  1465 |     - |  13M|   0 | 164 | 723 |1368 | 723
|1439 |  75 |   1 |   0 | 8.287500e-01 | 9.783333e-01 |  18.05%
Adding cut cons_vc2_6_10_3_11: 0 <= +1<t_y_(11,6)_6> +1<t_x_(6,10)_[3->10]>
+1<t_x_(11,3)_[7->10]> <= 2
Adding cut cons_vc2_6_10_11_6: 0 <= +1<t_x_(6,10)_[3->10]>
+1<t_x_(11,3)_[7->10]> +1<t_y_(11,6)_6> <= 2
scipmincon.linux.x86_64.gnu.dbg.cpx: src/scip/lp.c:6037:
SCIProwGetScalarProduct: Assertion `row2->nonlpcolssorted' failed.
Aborted

The stack trace is

#0  0x00002aaaabfc9d95 in raise () from /lib64/libc.so.6
#1  0x00002aaaabfcb2ab in abort () from /lib64/libc.so.6
#2  0x00002aaaabfc28fe in __assert_fail_base () from /lib64/libc.so.6
#3  0x00002aaaabfc29a2 in __assert_fail () from /lib64/libc.so.6
#4  0x00000000005325b3 in SCIProwGetScalarProduct (row1=0x21060d0,
row2=0x2105da0) at src/scip/lp.c:6037
#5  0x0000000000532b72 in SCIProwGetParallelism (row1=0x21060d0,
row2=0x2105da0, orthofunc=101 'e') at src/scip/lp.c:6125
#6  0x0000000000532cbe in SCIProwGetOrthogonality (row1=0x21060d0,
row2=0x2105da0, orthofunc=101 'e') at src/scip/lp.c:6151
#7  0x0000000000631268 in sepastoreUpdateOrthogonalities
(sepastore=0x175d7d0, blkmem=0x145e1b0, set=0x14601d0,
eventqueue=0x16387b0, eventfilter=0x1698e40, lp=0x1638360, cut=0x21060d0,
mincutorthogonality=0.5) at src/scip/sepastore.c:614
#8  0x000000000063159f in sepastoreApplyCut (sepastore=0x175d7d0,
blkmem=0x145e1b0, set=0x14601d0, eventqueue=0x16387b0,
eventfilter=0x1698e40, lp=0x1638360, cut=0x21060d0,
mincutorthogonality=0.5, depth=6, ncutsapplied=0x7fffffffcf80) at
src/scip/sepastore.c:670
#9  0x0000000000631bce in SCIPsepastoreApplyCuts (sepastore=0x175d7d0,
blkmem=0x145e1b0, set=0x14601d0, stat=0x156ccc0, tree=0x17ca160,
lp=0x1638360, branchcand=0x16382d0, eventqueue=0x16387b0,
eventfilter=0x1698e40, root=0, cutoff=0x7fffffffd6fc) at
src/scip/sepastore.c:817
#10 0x000000000064ebd7 in priceAndCutLoop (blkmem=0x145e1b0, set=0x14601d0,
stat=0x156ccc0, prob=0x17b42c0, primal=0x17ca0b0, tree=0x17ca160,
lp=0x1638360, pricestore=0x175d710, sepastore=0x175d7d0, cutpool=0x1908a00,
branchcand=0x16382d0, conflict=0x17ca330, eventfilter=0x1698e40,
eventqueue=0x16387b0, initiallpsolved=0, cutoff=0x7fffffffd6fc,
unbounded=0x7fffffffd6f8, lperror=0x7fffffffd548,
pricingaborted=0x7fffffffd54c) at src/scip/solve.c:2112
#11 0x000000000064ffcb in solveNodeLP (blkmem=0x145e1b0, set=0x14601d0,
stat=0x156ccc0, origprob=0x156d6e0, transprob=0x17b42c0, primal=0x17ca0b0,
tree=0x17ca160, lp=0x1638360, pricestore=0x175d710, sepastore=0x175d7d0,
cutpool=0x1908a00, branchcand=0x16382d0, conflict=0x17ca330,
eventfilter=0x1698e40, eventqueue=0x16387b0, initiallpsolved=0,
cutoff=0x7fffffffd6fc, unbounded=0x7fffffffd6f8, lperror=0x7fffffffd548,
pricingaborted=0x7fffffffd54c) at src/scip/solve.c:2434
#12 0x000000000065216f in propAndSolve (blkmem=0x145e1b0, set=0x14601d0,
stat=0x156ccc0, origprob=0x156d6e0, transprob=0x17b42c0, primal=0x17ca0b0,
tree=0x17ca160, lp=0x1638360, relaxation=0x162fa50, pricestore=0x175d710,
sepastore=0x175d7d0, branchcand=0x16382d0, cutpool=0x1908a00,
conflict=0x17ca330, eventfilter=0x1698e40, eventqueue=0x16387b0,
focusnode=0x2aaaad505650, actdepth=6, timingmask=1, propagate=1, solvelp=1,
solverelax=1, forcedlpsolve=0, nlperrors=0x7fffffffd56c,
fullpropagation=0x7fffffffd554, propagateagain=0x7fffffffd558,
initiallpsolved=0x7fffffffd564, solvelpagain=0x7fffffffd55c,
solverelaxagain=0x7fffffffd560, cutoff=0x7fffffffd6fc,
unbounded=0x7fffffffd6f8, lperror=0x7fffffffd548,
pricingaborted=0x7fffffffd54c, forcedenforcement=0x7fffffffd544) at
src/scip/solve.c:3036
#13 0x0000000000652eda in solveNode (blkmem=0x145e1b0, set=0x14601d0,
stat=0x156ccc0, origprob=0x156d6e0, transprob=0x17b42c0, primal=0x17ca0b0,
tree=0x17ca160, lp=0x1638360, relaxation=0x162fa50, pricestore=0x175d710,
sepastore=0x175d7d0, branchcand=0x16382d0, cutpool=0x1908a00,
conflict=0x17ca330, eventfilter=0x1698e40, eventqueue=0x16387b0,
cutoff=0x7fffffffd6fc, unbounded=0x7fffffffd6f8, infeasible=0x7fffffffd6f4,
restart=0x7fffffffd888, afternodeheur=0x7fffffffd6ec) at
src/scip/solve.c:3269
#14 0x00000000006558b9 in SCIPsolveCIP (blkmem=0x145e1b0, set=0x14601d0,
stat=0x156ccc0, mem=0x145c120, origprob=0x156d6e0, transprob=0x17b42c0,
primal=0x17ca0b0, tree=0x17ca160, lp=0x1638360, relaxation=0x162fa50,
pricestore=0x175d710, sepastore=0x175d7d0, cutpool=0x1908a00,
branchcand=0x16382d0, conflict=0x17ca330, eventfilter=0x1698e40,
eventqueue=0x16387b0, restart=0x7fffffffd888) at src/scip/solve.c:3854
#15 0x00000000005e7ed0 in SCIPsolve (scip=0x145c010) at src/scip/scip.c:7562
#16 0x000000000062ca33 in fromCommandLine (scip=0x145c010,
filename=0x7fffffffe41d "fsg/polska.fsg") at src/scip/scipshell.c:135
#17 0x000000000062d2ef in SCIPprocessShellArguments (scip=0x145c010,
argc=3, argv=0x7fffffffdf78, defaultsetname=0xfd1b47 "scipmincon.set") at
src/scip/scipshell.c:341
#18 0x0000000000408773 in runSCIP (argc=3, argv=0x7fffffffdf78) at
src/cppmain.cpp:85
#19 0x000000000040893c in main (argc=3, argv=0x7fffffffdf78) at
src/cppmain.cpp:123

At the beginning of SCIProwGetScalarProduct, the rows are sorted:

/* make sure, the rows are sorted */
SCIProwSort(row1);
assert(row1->lpcolssorted);
assert(row1->nonlpcolssorted);
SCIProwSort(row2);
assert(row2->lpcolssorted);
assert(row2->nonlpcolssorted);

In SCIProwSort, the method rowSortNonLP is called, and this is where
strange things happen:

/* check, if row is already sorted in the non-LP part, or if the sorting
should be delayed */
if( row->nonlpcolssorted || row->delaysort )
  return;

For my row, I get row->nonlpcolssorted = 0 and row->delaysort = 1, which is
why the method returns without actually doing something, and the assertion
fails.

This is too deep inside of SCIP's guts for me to understand. If you have an
idea what usually triggers this error, and what I could do to prevent it, I
would greatly appreciate it.
BTW, this happens in version 2.1.1 as well as 2.1.0.

Best regards,

  Daniel
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