[gmx-users] grompp single vs double precisions

[Yang Ye]

rob yang wrote:
> hi list,
> i am comparing the relative energy differences between different 
> conformations of a same molecule in vaccuum. i am using both gromacs 
> and another software to compare the results. the forcefield for both 
> softwares is oplsaa (2001), and i've manually verified that they are 
> indeed the same for my molecule as well as the partial charges.
> the relative energy results obtained from these 2 softwares are 
> different. i understand that different softwares have different 
> implementations but i think i should be able to get a similiar 
> relative energies for these conformations.
> so i am thinking maybe the minimizations is where things went wrong. i 
> have compiled the double version of mdrun. but i didn't for grompp 
> since i didn't think it was necessary. the question i have for you 
> guys is then: is the double version of grompp also necessary?
I didn't see your problem just now. For your case, definitely you need
double version for grompp to the result to be more precise.

Yang Ye