[Pw_forum] Is there a large difference between vc-relax calculation using "damp", "damp-w" and "bfgs", "bfgs" algorithm

[mohnish pandey]

Dear users !
                    I tried to calculate bulk energy and equilibrium lattice
parameters of some system using vc-relax calculation. I done the calculation
using both the algorithm naming (1)damped dynamics means 'ion_dynamics' as
"damp" and 'cell_dynamics' as "damp-w" (2) BFGS means 'ion_dynamics' as
"bfgs" and 'cell_dynamics' as"bfgs" .  I have changed only these two things
in these two alogorithm. But first case was taking very much time(~2hours)
and wasnt convergence after 200 ionic steps whereas in the second case it
took very less time (6-7 minutes) to get equilbrium bulk structure. Can
anybody please explain me what is the thing which is making so much
differnce?
Sincere thanks in advance,
Mohnish

-- 
Mohnish Pandey
Y6262,4th Year Undergraduate,
Department of Chemical Engineering,
IIT KANPUR
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