[Scip] free transform problem

James Cussens james.cussens at york.ac.uk
Fri Jul 6 11:43:53 MEST 2012


I'm using a subscip in a separator routine. Rather than using
createProb to create a brand new subscip on each separator call, I've
been 'recycling' the same one and using a call to freeTransform to
make the necessary changes before solving.

Although this has worked OK in some past versions of my project, I'm
now getting problems. My call to  SCIPfreeTransform
is failing when SCIP tries to reset bounds (see below).

Should I just create a new problem on each call? (I notice that the
SCIP separators do this.)
This would mean creating and adding the same variables (and many
constraints) over and over again.

James


gobnilp: src/scip/var.c:8082: SCIPvarResetBounds: Assertion
`SCIPvarGetTransVar(var) == ((void *)0)' failed.

Program received signal SIGABRT, Aborted.
0x00007ffff679c035 in raise () from /lib64/libc.so.6
(gdb) backtrace
#0  0x00007ffff679c035 in raise () from /lib64/libc.so.6
#1  0x00007ffff679d9e6 in abort () from /lib64/libc.so.6
#2  0x00007ffff67948e5 in __assert_fail () from /lib64/libc.so.6
#3  0x0000000000673549 in SCIPvarResetBounds (var=0x16f6b90,
blkmem=0x1511a50, set=0x1513a70, stat=0x16f1310) at
src/scip/var.c:8082
#4  0x00000000005ab999 in SCIPprobResetBounds (prob=0x16f1d60,
blkmem=0x1511a50, set=0x1513a70, stat=0x16f1310) at
src/scip/prob.c:514
#5  0x00000000005cd4c3 in freeTransform (scip=0x150f8b0) at src/scip/scip.c:7322
#6  0x00000000005cebaf in SCIPfreeTransform (scip=0x150f8b0) at
src/scip/scip.c:7764
#7  0x000000000040ab5b in DagClusterSeparate (scip=0x140c010,
consdata=0x15058a0, sol=0x175f018, nGen=0x7fffffffce90, ub=0,
add_cutting_planes=0) at src/cons_dagcluster.c:176

the comment in var.c says:
  /* resetting of bounds on original variables which have a
transformed counterpart easily fails if, e.g.,
    * the transformed variable has been fixed */
   assert(SCIPvarGetTransVar(var) == NULL);

-- 
James Cussens
Dept of Computer Science &
York Centre for Complex Systems Analysis
Room 326, The Hub, Deramore Lane            Tel    +44 (0)1904 325371
University of York                                        Fax  +44
(0)1904 500159
York YO10 5GE, UK                               http://www.cs.york.ac.uk/~jc


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