Process finished with exit code -1073741819 (0xC0000005)

[Huang-Jiayan]

When I used PySCIPOpt to solve a MILP, I encountered the following issue:

Process finished with exit code -1073741819 (0xC0000005)

I exported the MILP to an .lp file, and I can consistently reproduce the problem. However, when I rearranged the order of some constraints in the LP file, the model could be solved normally.

I would like to understand what might be causing this issue.
Is it related to memory access violations, constraint ordering sensitivity, or a bug in the solver?

For uploading the model file, I write it in the .txt

test.txt

[mmghannam]

Could you please specify which version of SCIP/PySCIPOpt do you have?
A log of the fail would also be helpful!

[Huang-Jiayan]

Could you please specify which version of SCIP/PySCIPOpt do you have? A log of the fail would also be helpful!

Yes, the version information: PySCIPOpt: 5.5.0, SCIP version 9.2.1 [precision: 8 byte] [memory: block] [mode: optimized] [LP solver: Soplex 7.1.3] [GitHash: NoGitInfo]

The solving logs are as follows:
original problem has 414 variables (48 bin, 2 int, 0 impl, 364 cont) and 572 constraints
presolving:
(round 1, fast) 333 del vars, 488 del conss, 0 add conss, 384 chg bounds, 0 chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 2, fast) 377 del vars, 523 del conss, 0 add conss, 415 chg bounds, 0 chg sides, 8 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 3, fast) 387 del vars, 529 del conss, 0 add conss, 430 chg bounds, 1 chg sides, 8 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 4, fast) 388 del vars, 529 del conss, 0 add conss, 433 chg bounds, 1 chg sides, 18 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 5, fast) 388 del vars, 529 del conss, 0 add conss, 435 chg bounds, 1 chg sides, 18 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 6, fast) 388 del vars, 529 del conss, 0 add conss, 436 chg bounds, 1 chg sides, 18 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 7, exhaustive) 388 del vars, 534 del conss, 0 add conss, 436 chg bounds, 3 chg sides, 18 chg coeffs, 0 upgd conss, 0 impls, 4 clqs
(round 8, exhaustive) 388 del vars, 534 del conss, 0 add conss, 436 chg bounds, 3 chg sides, 18 chg coeffs, 26 upgd conss, 0 impls, 4 clqs
(0.0s) probing cycle finished: starting next cycle
(0.0s) symmetry computation started: requiring (bin +, int +, cont +), (fixed: bin -, int -, cont -)
(0.0s) symmetry computation finished: 6 generators found (max: 1500, log10 of symmetry group size: 0.0) (symcode time: 0.00)

Process finished with exit code -1073741819 (0xC0000005)

Could you please tell me which version of PySCIPOpt you're using? I can try using the same one.

[DominikKamp]

Seems like an issue in symmetry computation where also on latest v92-bugfix

Assertion failed: (SCIPvarIsBinary(var)), function SCIPcreateConsOrbitope, file cons_orbitope.c, line 3778.

at

    frame #4: 0x000000010023fe10 scip`SCIPcreateConsOrbitope(scip=0x0000600001a0c000, cons=0x000000016fdfd158, name="doublelex_cols_1_0", vars=0x000000014600b7b0, orbitopetype=SCIP_ORBITOPETYPE_FULL, nspcons=2, nblocks=2, usedynamicprop=0, mayinteract=0, resolveprop=1, ismodelcons=0, initial=1, separate=1, enforce=0, check=1, propagate=1, local=0, modifiable=0, dynamic=0, removable=0, stickingatnode=0) at cons_orbitope.c:3778:13
    frame #5: 0x000000010079f278 scip`handleDoublelLexMatrix(scip=0x0000600001a0c000, propdata=0x0000000144f12358, id=1, varidxmatrix=0x0000000145013d98, nrows=2, ncols=4, rowsbegin=0x0000000145074ff8, colsbegin=0x0000000145013dd8, nrowblocks=1, ncolblocks=2, success=0x000000016fdfd62c) at prop_symmetry.c:5966:10
    frame #6: 0x000000010079b664 scip`tryHandleSingleOrDoubleLexMatricesComponent(scip=0x0000600001a0c000, propdata=0x0000000144f12358, detectsinglelex=0, cidx=1) at prop_symmetry.c:6095:13
    frame #7: 0x000000010079719c scip`tryAddSymmetryHandlingMethodsComponent(scip=0x0000600001a0c000, propdata=0x0000000144f12358, cidx=1, nchgbds=0x000000016fdfd82c) at prop_symmetry.c:6211:7
    frame #8: 0x0000000100796360 scip`tryAddSymmetryHandlingMethods(scip=0x0000600001a0c000, prop=0x0000000144f126d0, nchgbds=0x000000016fdfd82c, earlyterm=0x000000016fdfd828) at prop_symmetry.c:6307:7
    frame #9: 0x00000001007920b0 scip`propPresolSymmetry(scip=0x0000600001a0c000, prop=0x0000000144f126d0, nrounds=8, presoltiming=16, nnewfixedvars=313, nnewaggrvars=75, nnewchgvartypes=0, nnewchgbds=436, nnewholes=0, nnewdelconss=534, nnewaddconss=0, nnewupgdconss=26, nnewchgcoefs=18, nnewchgsides=3, nfixedvars=0x0000000145008d4c, naggrvars=0x0000000145008d50, nchgvartypes=0x0000000145008d54, nchgbds=0x0000000145008d58, naddholes=0x0000000145008d5c, ndelconss=0x0000000145008d60, naddconss=0x0000000145008d64, nupgdconss=0x0000000145008d68, nchgcoefs=0x0000000145008d6c, nchgsides=0x0000000145008d70, result=0x000000016fdfdce0) at prop_symmetry.c:6498:4
    frame #10: 0x0000000100c14abc scip`SCIPpropPresol(prop=0x0000000144f126d0, set=0x000000014580e000, timing=16, nrounds=8, nfixedvars=0x0000000145008d4c, naggrvars=0x0000000145008d50, nchgvartypes=0x0000000145008d54, nchgbds=0x0000000145008d58, naddholes=0x0000000145008d5c, ndelconss=0x0000000145008d60, naddconss=0x0000000145008d64, nupgdconss=0x0000000145008d68, nchgcoefs=0x0000000145008d6c, nchgsides=0x0000000145008d70, result=0x000000016fdfdce0) at prop.c:604:7
    frame #11: 0x0000000100cd64ac scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:930:10
    frame #12: 0x0000000100cd72a8 scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:1079:13
    frame #13: 0x0000000100cd72a8 scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:1079:13
    frame #14: 0x0000000100cc9684 scip`presolve(scip=0x0000600001a0c000, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, vanished=0x000000016fdfe5a4) at scip_solve.c:1251:7
    frame #15: 0x0000000100cc7ce4 scip`SCIPpresolve(scip=0x0000600001a0c000) at scip_solve.c:2373:7
    frame #16: 0x0000000100ccc3e8 scip`SCIPsolve(scip=0x0000600001a0c000) at scip_solve.c:2611:10
    frame #17: 0x000000010034e140 scip`SCIPdialogExecOptimize(scip=0x0000600001a0c000, dialog=0x000060000010a940, dialoghdlr=0x0000600002b09110, nextdialog=0x000000016fdfe870) at dialog_default.c:2194:7
    frame #18: 0x00000001009dd834 scip`SCIPdialogExec(dialog=0x000060000010a940, set=0x000000014580e000, dialoghdlr=0x0000600002b09110, nextdialog=0x000000016fdfe870) at dialog.c:951:4
    frame #19: 0x00000001009dd674 scip`SCIPdialoghdlrExec(dialoghdlr=0x0000600002b09110, set=0x000000014580e000) at dialog.c:402:7
    frame #20: 0x0000000100c7368c scip`SCIPstartInteraction(scip=0x0000600001a0c000) at scip_dialog.c:252:4
    frame #21: 0x0000000100d1a0d8 scip`SCIPprocessShellArguments(scip=0x0000600001a0c000, argc=7, argv=0x000000016fdff520, defaultsetname="scip.set") at scipshell.c:538:10
    frame #22: 0x0000000100d1b258 scip`SCIPrunShell(argc=7, argv=0x000000016fdff520, defaultsetname="scip.set") at scipshell.c:594:4
    frame #23: 0x000000010000557c scip`main(argc=7, argv=0x000000016fdff520) at main.c:71:14
    frame #24: 0x000000019158ab98 dyld`start + 6076

[Huang-Jiayan]

Seems like an issue in symmetry computation where also on latest v92-bugfix

Assertion failed: (SCIPvarIsBinary(var)), function SCIPcreateConsOrbitope, file cons_orbitope.c, line 3778.

at

    frame #4: 0x000000010023fe10 scip`SCIPcreateConsOrbitope(scip=0x0000600001a0c000, cons=0x000000016fdfd158, name="doublelex_cols_1_0", vars=0x000000014600b7b0, orbitopetype=SCIP_ORBITOPETYPE_FULL, nspcons=2, nblocks=2, usedynamicprop=0, mayinteract=0, resolveprop=1, ismodelcons=0, initial=1, separate=1, enforce=0, check=1, propagate=1, local=0, modifiable=0, dynamic=0, removable=0, stickingatnode=0) at cons_orbitope.c:3778:13
    frame #5: 0x000000010079f278 scip`handleDoublelLexMatrix(scip=0x0000600001a0c000, propdata=0x0000000144f12358, id=1, varidxmatrix=0x0000000145013d98, nrows=2, ncols=4, rowsbegin=0x0000000145074ff8, colsbegin=0x0000000145013dd8, nrowblocks=1, ncolblocks=2, success=0x000000016fdfd62c) at prop_symmetry.c:5966:10
    frame #6: 0x000000010079b664 scip`tryHandleSingleOrDoubleLexMatricesComponent(scip=0x0000600001a0c000, propdata=0x0000000144f12358, detectsinglelex=0, cidx=1) at prop_symmetry.c:6095:13
    frame #7: 0x000000010079719c scip`tryAddSymmetryHandlingMethodsComponent(scip=0x0000600001a0c000, propdata=0x0000000144f12358, cidx=1, nchgbds=0x000000016fdfd82c) at prop_symmetry.c:6211:7
    frame #8: 0x0000000100796360 scip`tryAddSymmetryHandlingMethods(scip=0x0000600001a0c000, prop=0x0000000144f126d0, nchgbds=0x000000016fdfd82c, earlyterm=0x000000016fdfd828) at prop_symmetry.c:6307:7
    frame #9: 0x00000001007920b0 scip`propPresolSymmetry(scip=0x0000600001a0c000, prop=0x0000000144f126d0, nrounds=8, presoltiming=16, nnewfixedvars=313, nnewaggrvars=75, nnewchgvartypes=0, nnewchgbds=436, nnewholes=0, nnewdelconss=534, nnewaddconss=0, nnewupgdconss=26, nnewchgcoefs=18, nnewchgsides=3, nfixedvars=0x0000000145008d4c, naggrvars=0x0000000145008d50, nchgvartypes=0x0000000145008d54, nchgbds=0x0000000145008d58, naddholes=0x0000000145008d5c, ndelconss=0x0000000145008d60, naddconss=0x0000000145008d64, nupgdconss=0x0000000145008d68, nchgcoefs=0x0000000145008d6c, nchgsides=0x0000000145008d70, result=0x000000016fdfdce0) at prop_symmetry.c:6498:4
    frame #10: 0x0000000100c14abc scip`SCIPpropPresol(prop=0x0000000144f126d0, set=0x000000014580e000, timing=16, nrounds=8, nfixedvars=0x0000000145008d4c, naggrvars=0x0000000145008d50, nchgvartypes=0x0000000145008d54, nchgbds=0x0000000145008d58, naddholes=0x0000000145008d5c, ndelconss=0x0000000145008d60, naddconss=0x0000000145008d64, nupgdconss=0x0000000145008d68, nchgcoefs=0x0000000145008d6c, nchgsides=0x0000000145008d70, result=0x000000016fdfdce0) at prop.c:604:7
    frame #11: 0x0000000100cd64ac scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:930:10
    frame #12: 0x0000000100cd72a8 scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:1079:13
    frame #13: 0x0000000100cd72a8 scip`presolveRound(scip=0x0000600001a0c000, timing=0x000000016fdfe4b4, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, lastround=0, presolstart=0x000000016fdfe4a4, presolend=17, propstart=0x000000016fdfe4a0, propend=10, consstart=0x000000016fdfe49c, consend=29) at scip_solve.c:1079:13
    frame #14: 0x0000000100cc9684 scip`presolve(scip=0x0000600001a0c000, unbounded=0x000000016fdfe5ac, infeasible=0x000000016fdfe5a8, vanished=0x000000016fdfe5a4) at scip_solve.c:1251:7
    frame #15: 0x0000000100cc7ce4 scip`SCIPpresolve(scip=0x0000600001a0c000) at scip_solve.c:2373:7
    frame #16: 0x0000000100ccc3e8 scip`SCIPsolve(scip=0x0000600001a0c000) at scip_solve.c:2611:10
    frame #17: 0x000000010034e140 scip`SCIPdialogExecOptimize(scip=0x0000600001a0c000, dialog=0x000060000010a940, dialoghdlr=0x0000600002b09110, nextdialog=0x000000016fdfe870) at dialog_default.c:2194:7
    frame #18: 0x00000001009dd834 scip`SCIPdialogExec(dialog=0x000060000010a940, set=0x000000014580e000, dialoghdlr=0x0000600002b09110, nextdialog=0x000000016fdfe870) at dialog.c:951:4
    frame #19: 0x00000001009dd674 scip`SCIPdialoghdlrExec(dialoghdlr=0x0000600002b09110, set=0x000000014580e000) at dialog.c:402:7
    frame #20: 0x0000000100c7368c scip`SCIPstartInteraction(scip=0x0000600001a0c000) at scip_dialog.c:252:4
    frame #21: 0x0000000100d1a0d8 scip`SCIPprocessShellArguments(scip=0x0000600001a0c000, argc=7, argv=0x000000016fdff520, defaultsetname="scip.set") at scipshell.c:538:10
    frame #22: 0x0000000100d1b258 scip`SCIPrunShell(argc=7, argv=0x000000016fdff520, defaultsetname="scip.set") at scipshell.c:594:4
    frame #23: 0x000000010000557c scip`main(argc=7, argv=0x000000016fdff520) at main.c:71:14
    frame #24: 0x000000019158ab98 dyld`start + 6076

So is this a bug in PySCIPOpt, or is there something wrong with my model?
Could you tell me how to avoid this issue?

[svigerske]

The bug is in SCIP. Setting option misc/usesymmetry = 0 should work around it. CC @christopherhojny

[DominikKamp]

A less invasive workaround should be propagating/symmetry/detectdoublelex = FALSE.

[Huang-Jiayan]

A less invasive workaround should be propagating/symmetry/detectdoublelex = FALSE.

Thanks a lot, it actually worked!

[Huang-Jiayan]

The bug is in SCIP. Setting option misc/usesymmetry = 0 should work around it. CC @christopherhojny

Thanks a lot, it actually worked!

[christopherhojny]

The bug should also be gone on the current master branch (at least I could not reproduce it there), because the corresponding part of the symmetry code has been completely reworked.