[Scip] freeing unknown pointer error

James Cussens jc at cs.york.ac.uk
Wed Feb 9 09:40:22 MET 2011


Hi all,

I'm getting an error and I can't work out what's causing it. I'm 
hoping someone can give me some idea of what's going on.

I'm using a sub-MIP to find cutting planes in a constraint handler 
I've written. Each time the sub-MIP is used only the objective 
function changes (not the feasible region) so I just call 
SCIPfreeTransform before each call to the sub-MIP. On most problems 
everything works fine, but on my biggest I get the following error 
when SCIP gets to SCIPtransformProb on the sub-MIP:

[src/blockmemshell/memory.c:903] ERROR: Tried to free unknown pointer 
<0xa2a2118>
[src/blockmemshell/memory.c:903] ERROR: Tried to free unknown pointer 
<0xa6e6418>
[src/blockmemshell/memory.c:903] ERROR: Tried to free unknown pointer 
<0xedb2dd8>
[src/blockmemshell/memory.c:903] ERROR: Tried to free unknown pointer 
<0xcca5018>

This occurs as soon as we start branching on the main SCIP problem. 
The following (truncated) gdb stack trace might be useful.

Any help gratefully received!

James


Program received signal SIGABRT, Aborted.
0xb7c7aa67 in raise () from /lib/libc.so.6
(gdb) info stack
#0  0xb7c7aa67 in raise () from /lib/libc.so.6
#1  0xb7c7c2e2 in abort () from /lib/libc.so.6
#2  0xb7cb905d in __libc_message () from /lib/libc.so.6
#3  0xb7cbf5aa in malloc_printerr () from /lib/libc.so.6
#4  0xb7cc2503 in _int_free () from /lib/libc.so.6
#5  0xb7cc56b0 in free () from /lib/libc.so.6
#6  0x083e0151 in removeMemlistEntry (ptr=0x9672948, 
filename=0x897fc60 "src/blockmemshell/memory.c", line=903) at 
src/blockmemshell/memory.c:163
#7  0x083e0540 in BMSfreeMemory_call (ptr=0x9672948, 
filename=0x897fc60 "src/blockmemshell/memory.c", line=903) at 
src/blockmemshell/memory.c:392
#8  0x083e115e in destroyChunk (chunk=0x9672948) at 
src/blockmemshell/memory.c:903
#9  0x083e167b in clearChkmem (chkmem=0xa363110) at 
src/blockmemshell/memory.c:1054
#10 0x083e18fb in garbagecollectChkmem (chkmem=0xa363110) at 
src/blockmemshell/memory.c:1140
#11 0x083e2606 in BMSgarbagecollectBlockMemory_call (blkmem=0x8d5cf78) 
at src/blockmemshell/memory.c:1746
#12 0x080a0ec7 in SCIPtransformProb (scip=0x8d5be90) at 
src/scip/scip.c:5641
#13 0x080a4df3 in SCIPpresolve (scip=0x8d5be90) at src/scip/scip.c:6632
#14 0x080a55a8 in SCIPsolve (scip=0x8d5be90) at src/scip/scip.c:6807
#15 0x0804f3a0 in DagClusterSeparate (scip=0x89e5008, 
consdata=0x8d1ac84, sol=0x0, nGen=0xbfffe7ec) at src/cons_dagcluster.c:117
#16 0x0804fbb2 in consSepalpDagcluster (scip=0x89e5008, 
conshdlr=0x8acc270, conss=0x9115248, nconss=1, nusefulconss=1, 
result=0xbfffe8c0) at src/cons_dagcluster.c:396
#17 0x08059967 in SCIPconshdlrSeparateLP (conshdlr=0x8acc270, 
blkmem=0x89e60f0, set=0x89e7110, stat=0x8c0fc20, sepastore=0x92db0d8, 
depth=1, execdelayed=0, result=0xbfffe8c0) at src/scip/cons.c:2465



More information about the Scip mailing list