How to turn on debug

User Support
1

Hi openmc expert,

I got this error while I attempt to run fixed source mode for the first time and sometimes I also got a segmentation fault error.

run
run798×689 15.2 KB

so I want to turn on debugging by following this instruction in 2.3.3.1 CMakelist option from openmc document and I try to run my problem again, but no error description appears. Could you tell me how to turn on debugging in detail? I’m so confused about it.

2

In this case, what you’ll want to do is:

  1. Go to a terminal and run gdb openmc in the directory where your XML files live
  2. Enter run to start the executable
  3. When it reaches a segfault, enter backtrace to get a full backtrace showing where the segfault happened.

As an example, here’s what I got when I tried a simulation with the source file you shared:

 ===============>     FIXED SOURCE TRANSPORT SIMULATION     <===============

 Simulating batch 1

Thread 1 "openmc" received signal SIGSEGV, Segmentation fault.
openmc::SourceDistribution::sample (this=0x5555555a9950, seed=0x7fffffffb238) at /home/romano/openmc/src/source.cpp:187
187	    site.r = space_->sample(seed);
(gdb) backtrace
#0  openmc::SourceDistribution::sample (this=0x5555555a9950, seed=0x7fffffffb238) at /home/romano/openmc/src/source.cpp:187
#1  0x00001555551b13b8 in openmc::sample_external_source (seed=0x7fffffffb238) at /home/romano/openmc/src/source.cpp:344
#2  0x00001555551adcbd in openmc::initialize_history (p=..., index_source=1) at /home/romano/openmc/src/simulation.cpp:460
#3  0x00001555551af11a in openmc::_ZN6openmc23transport_history_basedEv._omp_fn.0(void) () at /home/romano/openmc/src/simulation.cpp:694
#4  0x0000155553cef8e6 in GOMP_parallel () from /lib/x86_64-linux-gnu/libgomp.so.1
#5  0x00001555551aed81 in openmc::transport_history_based () at /home/romano/openmc/src/simulation.cpp:690
#6  0x00001555551ad3b2 in openmc_next_batch (status=0x7fffffffb990) at /home/romano/openmc/src/simulation.cpp:222
#7  0x00001555551acd86 in openmc_run () at /home/romano/openmc/src/simulation.cpp:59
#8  0x0000555555556348 in main (argc=1, argv=0x7fffffffbac8) at /home/romano/openmc/src/main.cpp:34