[Pw_forum] what is w1 and w2 for bfgs relaxed calculation

[yukihiro_okuno at fujifilm.co.jp]

Dear PWscf users.

I met not conserved force in relaxed calculation for slightly
titled crystal structure for PZT in order to get e15 piezoelectric
calculation.

So I want to remedy this problem.

In relaxed calculation in bfgs scheme, I set parametr w1 and w2 by
default value, but what is this parameter means?  and if this parameter
is important for improve the convergence for force, how should i
change this value when the force is not conserved.

Sincerely,