[gmx-users] Comparing single with double precision runs

[Kalavera at gmx.net]

Dear Gromacs-users,

I compiled a single and a double precision version of gromacs 4.5.4 (MPI enabled). The differences between single and double precision runs have been discussed in older threads (2005/2008) in this mailing list before. At least, I did not understand completely, which parts or calculations in an simulation are affected by my single/double precision choice. Some threads identified the equilibration step to be the most susceptible for differences. Is this true ? 

With each version (single and double precision), I calculated the same simulation (same seeds). Which observables/energies/tests should I observe or conduct to find and evaluate the differences ? For my system (protein/water/lipids), I would like to find out, if the calculation intensive double precision version has advantages, which are essential for a correct simulation.

Thanks for all your support,

Kalavera 
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