[Scip] Assertion: Objective limit not infinity in exact SCIP

[Matthias Walter]

Dear list,

I came across the following problem: This ZPL model

% cat obj-integral-bug.zpl
var x integer;

maximize cost: 1*x;

subto row0: 1*x <= 1;

produces the following assertion failure [1]. Is this indeed a bug or
can I do something about this?

Best regards,

Matthias Walter

[1] SCIP output:

% ~/software/exact-scip/scip-3.0.0-ex/bin/scip.linux.x86_64.gnu.dbg.spx
Using QSopt_ex (SVN-version 2.5.10:537, built Apr 20 2015-11:22:02)
Using EGlib (SVN-version 2.6.20:559M, built Apr 20 2015-11:14:51)
Using EG-GMP mempool
SCIP version 3.0.0 [precision: 8 byte] [memory: block] [mode: debug] [LP
solver: SoPlex 2.0.0] [Exact LP solver: QSopt_ex 2.5.10] [GitHash: e3f49b6]
Copyright (c) 2002-2012 Konrad-Zuse-Zentrum fuer Informationstechnik
Berlin (ZIB)

External codes:
  Readline 6.2         GNU library for command line editing
(gnu.org/s/readline)
  SoPlex 2.0.0         Linear Programming Solver developed at Zuse
Institute Berlin (soplex.zib.de) [GitHash: 568f354]
  QSopt_ex 2.5.10      Exact Linear Programming Solver by D. Espinoza,
W. Cook, S. Dash, and D. Applegate
(dii.uchile.cl/~daespino/QSoptExact_doc/main.html)
  EGlib 2.6.20         Library for basic structures and utilities by D.
Espinoza and M. Goycoolea (dii.uchile.cl/~daespino/EGlib_doc/main.html)
  cppad-20120101.3     Algorithmic Differentiation of C++ algorithms
developed by B. Bell (www.coin-or.org/CppAD)
  ZLIB 1.2.3.4         General purpose compression library by J. Gailly
and M. Adler (zlib.net)
  GMP 5.0.2            GNU Multiple Precision Arithmetic Library
developed by T. Granlund (gmplib.org)
  MPFR 3.1.0-p3        GNU Multiple Precision Floating-Point Reliable
Library (mpfr.org)
  ZIMPL 3.3.2          Zuse Institute Mathematical Programming Language
developed by T. Koch (zimpl.zib.de)

Reduced version of SCIP in EXACT mode (version 1.0.0):
  Algorithm: branch-and-bound
  Constraints: exact linear
  Branching: all standard plugins
  Readers: zpl (mps files can be converted with "mps2zpl.sh
filename.mps[.gz]")

user parameter file <scip.set> not found - using default parameters

SCIP> read obj-integral-bug.zpl

read problem <obj-integral-bug.zpl>
============


base directory for ZIMPL parsing: </home/xammy>

original problem has 1 variables (0 bin, 1 int, 0 impl, 0 cont) and 1
constraints
SCIP> opt

scip.linux.x86_64.gnu.dbg.spx: src/scip/cons_exactlp.c:2073:
checkObjIntegral: Assertion `SCIPisInfinity(scip,
SCIPgetObjlimit(scip))' failed.
Aborted (core dumped)