There could be several reasons: 1) if the number of SCF iterations is very large (say > 200) then your input parameters are bad, then check for mixing parameters etc. 2) You have compiled siesta with slow optimizations. 3) You probably don't need MPI for this small simulation, it may yield a worse performance. 4) You have a slow computer.
Den ons. 27. jun. 2018 kl. 22.11 skrev El-abed Haidar < [email protected]>: > Hello again, > > I am calculating the cohesive energy by finding the energy of a single > atom. In my code, I am interested in calculating the cohesive energy for > different cutoff energies (b in the code) while finding the optimised > lattice constant (a in code). > > The reason the code at the moment is only one value of cut off is that for > only one run, the time taken is around one full day. I am not expecting > that at all. > > The lattice vectors are clearly larger than 10 A while using only one K > point. Based on my parameters what is slowing down my code that much? > > Thank you and looking forward to your reply. > > EL-Abed > > > El-abed Haidar | Doctor of Philosophy (Science) > Condensed Matter Theory (CMT) Group > | School of Physics > THE UNIVERSITY OF SYDNEY | NSW | 2006 > > -- Kind regards Nick
