[Pw_forum] Convergence on vc-relax

[Sergei Lisenkov]

Dear PWscf users and authors,

I'm performing the variable-cell relaxation (vc-relax) after usual relaxation. 
I look and see, that 
  
....
     atom  31 type  1   force =     0.00008441    0.00003489    0.00003534
     atom  32 type  2   force =     0.00012384   -0.00012982   -0.00003111
     atom  33 type  1   force =     0.00001294   -0.00016967    0.00006886
     atom  34 type  1   force =    -0.00001421   -0.00010447   -0.00002003
     atom  35 type  2   force =    -0.00014640    0.00000794   -0.00008082
     atom  36 type  2   force =     0.00009507   -0.00001322   -0.00000765
     atom  37 type  1   force =    -0.00002926   -0.00004662    0.00004737
     atom  38 type  1   force =     0.00007443   -0.00003407    0.00003993
     atom  39 type  2   force =     0.00021791   -0.00002488   -0.00001346
     atom  40 type  2   force =    -0.00000974   -0.00003529   -0.00007173
     atom  41 type  1   force =    -0.00001142   -0.00001933    0.00005107
     atom  42 type  2   force =    -0.00018377   -0.00001689    0.00002445
     atom  43 type  1   force =    -0.00005966    0.00000411    0.00009872
     atom  44 type  1   force =     0.00003508   -0.00001891    0.00011726
     atom  45 type  2   force =    -0.00002095    0.00009382   -0.00005525
     atom  46 type  2   force =     0.00020613    0.00000553   -0.00013155
     atom  47 type  1   force =    -0.00006796   -0.00000820    0.00005802
     atom  48 type  2   force =     0.00018790    0.00003364   -0.00004945

     Total force =     0.000949     Total SCF correction =     0.007719


     entering subroutine stress ...

          total   stress  (ryd/bohr**3)                  (kbar)     P=  -66.95
  -0.00035456  -0.00000021   0.00000010        -52.16     -0.03      0.02
  -0.00000021  -0.00050533   0.00000000         -0.03    -74.34      0.00
   0.00000010   0.00000000  -0.00050542          0.02      0.00    -74.35

.....

What is threshold of vc-relax ?

Thanks,
 Sergey