some problem when run mpi example

[yejian-uestc]

• ns3 version (cat $NS3FOLDER/VERSION or the commit hash): ns3.26
• DCE version (git log|head -n1): 1.9
• Operating system/version (lsb_release -a): ubuntu14.04
• Libc version (ldd -v):
• compiler version (gcc -v/g++ -v/clang -v/clang++ -v):

Description of the problem

1. First, I add "--enable-mpi" in "bakeconf.xml" before I run "bake.py download" and "bake.py build".

2. Next, I run the mpi example in "ns-3.26", it work well.

3. Then, I run the mpi example in "ns-3-dce" ( mpirun -np 2 ./waf --run dce-mpi-udp), it work well at the fisrt time. But when I run again, I get erro.

4. When I rebuild the ns-3-dce, I can run the example successful. But when I run again, I get erro too.

output of "mpirun -np 2 ./waf --run dce-mpi-udp"

Waf: Leaving directory `/home/test/workspace/dce/source/ns-3-dce/build'
Waf: Leaving directory `/home/test/workspace/dce/source/ns-3-dce/build'
Traceback (most recent call last):
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Scripting.py", line 97, in waf_entry_point
    run_commands()
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Scripting.py", line 151, in run_commands
    run_command(cmd_name)
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Scripting.py", line 143, in run_command
'build' finished successfully (0.247s)
    ctx.execute()
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Scripting.py", line 345, in execute
    return execute_method(self)
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Build.py", line 98, in execute
    self.execute_build()
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Build.py", line 107, in execute_build
    self.compile()
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Build.py", line 188, in compile
    self.store()
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Utils.py", line 310, in f
    ret=fun(*k,**kw)
  File "/home/test/workspace/dce/source/ns-3-dce/.waf-1.6.11-30618c54883417962c38f5d395f83584/waflib/Build.py", line 175, in store
    os.rename(db+'.tmp',db)
OSError: [Errno 2] No such file or directory
--------------------------------------------------------------------------
mpirun has exited due to process rank 0 with PID 8839 on
node test-virtual-machine exiting improperly. There are two reasons this could occur:

1. this process did not call "init" before exiting, but others in
the job did. This can cause a job to hang indefinitely while it waits
for all processes to call "init". By rule, if one process calls "init",
then ALL processes must call "init" prior to termination.

2. this process called "init", but exited without calling "finalize".
By rule, all processes that call "init" MUST call "finalize" prior to
exiting or it will be considered an "abnormal termination"

This may have caused other processes in the application to be
terminated by signals sent by mpirun (as reported here).

When I run the mpi example in "ns3.26", it work well. But when I run the mpi example in "ns-3-dce", I get these erro, so anyone know how to solve this? Thanks!