Hybrid benchmark to test CP2K scaling up to 10000s of cores
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input_bulk_HFX_3.inp:  is the actual benchmark
input_bulk_B88_3.inp:  needed to generate an initial wfn for the HFX runs (not part of the benchmark)

the additional files t_c_g.dat and POTENTIAL are needed, and can be found in the tests/QS directory.
To run these this benchmark, CP2K needs to be compiled with libint support (-D__LIBINT), and it is advantages
to have a OMP/MPI hybrid code (cp2k.psmp). 

1) run input_bulk_B88_3.inp and copy the last LiH_bulk_3-RESTART.wfn to B88.wfn (5min. with 256x1 mpixomp tasks)
2) run input_bulk_HFX_3.inp on a number of nodes (about 30min on 2048 cores)

The obtained energies be similar to (obtained on 2048 MPI x 8 OMP cores):

     1  OT CG          0.15E+00    139.386     0.0014482195     -870.3838179520
     2  OT LS          0.30E+00     19.767     1.0000000000     -870.7951031236
     3  OT CG          0.30E+00     20.724     0.0001614074     -870.9275954835
     4  OT LS          0.31E+00     19.665     1.0000000000     -870.9346994255
     5  OT CG          0.31E+00     20.641     0.0000168390     -870.9347195049
     6  OT LS          0.29E+00     19.760     1.0000000000     -870.9347906736
     7  OT CG          0.29E+00     21.192     0.0000009576     -870.9347911831

2009-04-15, running on ORNL's Cray XT5 (Jaguar) the following runtime has been obtained in a setup using 8 OMP threads per node (8 cores per node / 16 Gb per node),

#  cores |     Full CP2K[s] |           HFX[s] |     local HFX[s] |     Mem/node[Mb]   
    1024            6569.07            6488.24            6406.99           14845.00     
    2048            1369.92            1314.86            1259.82           13468.00     
    4096             722.24             670.18             631.11            7293.00     
    8192             402.18             352.21             317.59            4306.00     
   16384             274.41             213.88             172.88            2801.00     
   32768             201.71             135.47              85.29            2046.00     
   65536             255.97             117.33              41.43            1673.00     


