[Pw_forum] Relaxation doesn't converge

[Paolo Giannozzi]

Pablo Aguado wrote:

> All I can say is that it seems to be converged

"it seems" /= "it is"

> press_conv_thr = 1.0d0

this is internally called "epsp"

>          total   stress  (Ry/bohr**3)                   (kbar)     P=   -0.84
>  -0.00001150   0.00000000   0.00000000         -1.69      0.00      0.00
>   0.00000000  -0.00001150   0.00000000          0.00     -1.69      0.00
>   0.00000000   0.00000000   0.00000591          0.00      0.00      0.87

and this is where the convergence is checked: PW/vcsmd.f90, line 212
and following:

      DO i = 1, 3
         !
         conv_ions = conv_ions .AND. &
                     ( ABS( sigma(i,i) - press) * uakbar < epsp )
         !
         DO j = ( i + 1 ), 3
            conv_ions = conv_ions .AND. &
                        ( ABS( sigma(i,j) ) * uakbar < epsp )
         END DO
         !
      END DO

press=external pressure, sigma=stress tensor,
uakbar=atomic units to KBar conversion factor.

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy