[Ranjan]

Hello

I am trying to run the Inviscid ONERA m6 wing optimization tutorial on a local workstation with 8 cores. While executing the shape_optimization.py script in parallel using 4 cores, the optimization runs and converges eventually. However, if I increase the number of cores, the python script results in the exception listed below. I am wondering if others have faced a similar issue ?

File "/usr/local/bin/shape_optimization.py", line 183, in <module>
main()
File "/usr/local/bin/shape_optimization.py", line 98, in main
options.nzones )
File "/usr/local/bin/shape_optimization.py", line 159, in shape_optimization
SU2.opt.SLSQP(project,x0,xb,its,accu)
File "/usr/local/bin/SU2/opt/scipy_tools.py", line 133, in scipy_slsqp
epsilon = eps )
File "/usr/local/lib/python2.7/dist-packages/scipy/optimize/slsqp.py", line 208, in fmin_slsqp
constraints=cons, **opts)
File "/usr/local/lib/python2.7/dist-packages/scipy/optimize/slsqp.py", line 315, in _minimize_slsqp
for c in cons['ineq']]))
File "/usr/local/bin/SU2/opt/scipy_tools.py", line 457, in con_cieq
cons = project.con_cieq(x)
File "/usr/local/bin/SU2/opt/project.py", line 257, in con_cieq
return self._eval(konfig, func,dvs)
File "/usr/local/bin/SU2/opt/project.py", line 206, in _eval
vals = design._eval(func,*args)
File "/usr/local/bin/SU2/eval/design.py", line 147, in _eval
vals = eval_func(*inputs)
File "/usr/local/bin/SU2/eval/design.py", line 520, in con_cieq
func = su2func(this_con,config,state)
File "/usr/local/bin/SU2/eval/functions.py", line 104, in function
geometry( func_name, config, state )
File "/usr/local/bin/SU2/eval/functions.py", line 834, in geometry
info = su2run.geometry(config)
File "/usr/local/bin/SU2/run/geometry.py", line 96, in geometry
SU2_GEO(konfig)
File "/usr/local/bin/SU2/run/interface.py", line 208, in GEO
run_command( the_Command )
File "/usr/local/bin/SU2/run/interface.py", line 292, in run_command
raise exception(message)
SU2.EvaluationFailure: Path = /media/prateek/NACA0012_Numerical_exp/Wing_Optimization/ONERA/Inviscid/Optimization/Test/DESIGNS/DSN_001/GEOMETRY/,
Command = mpirun -n 8 /usr/local/bin/SU2_GEO config_GEO.cfg
SU2 process returned error '1'
Invalid MIT-MAGIC-COOKIE-1 key--------------------------------------------------------------------------
There are not enough slots available in the system to satisfy the 8
slots that were requested by the application:

/usr/local/bin/SU2_GEO

Either request fewer slots for your application, or make more slots
available for use.

A "slot" is the Open MPI term for an allocatable unit where we can
launch a process. The number of slots available are defined by the
environment in which Open MPI processes are run:

1. Hostfile, via "slots=N" clauses (N defaults to number of
processor cores if not provided)
2. The --host command line parameter, via a ":N" suffix on the
hostname (N defaults to 1 if not provided)
3. Resource manager (e.g., SLURM, PBS/Torque, LSF, etc.)
4. If none of a hostfile, the --host command line parameter, or an
RM is present, Open MPI defaults to the number of processor cores

In all the above cases, if you want Open MPI to default to the number
of hardware threads instead of the number of processor cores, use the
--use-hwthread-cpus option.

Alternatively, you can use the --oversubscribe option to ignore the
number of available slots when deciding the number of processes to
launch.

[pcg]

It seems OpenMPI thinks you have 8 threads and not 8 cores, and so it is protecting you from using more processes than your hardware can efficiently handle.

[Ranjan]

Hi Pedro

You were correct! All this time I thought that my workstation had 8 cores but instead it had only 4 cores and 8 threads.

Thank you