[gmx-users] FEP and loss of performance

[Luca Bellucci]

Dear all,
when I run a single free energy simulation 
i noticed that there is a loss of performace with respect to
the normal MD

free_energy    = yes
init_lambda    = 0.9    
delta_lambda   = 0.0
couple-moltype = Protein_Chain_P
couple-lambda0 = vdw-q
couple-lambda0 = none
couple-intramol= yes

   Average load imbalance: 16.3 %
   Part of the total run time spent waiting due to load imbalance: 12.2 %
   Steps where the load balancing was limited by -rdd, -rcon and/or -dds: X0 %
   Time:   1852.712   1852.712    100.0

free_energy    = no
   Average load imbalance: 2.7 %
   Part of the total run time spent waiting due to load imbalance: 1.7 % 
   Time:    127.394    127.394    100.0

It seems that the loss of performace is due in part to in the load imbalance 
in the domain decomposition, however I tried to change
these keywords without benefit
Any comment is welcome.

Thanks