[Pw_forum] something wrong in relax, BFGS

xywu xywu at imr.ac.cn
Mon Apr 18 10:34:19 CEST 2005


Dear All,

  There're something wrong in relax.

The follows occurs:

---------------
     number of scf cycles    = 117
      number of bfgs steps    =  62

      energy old              =    -161.4284071964 ryd
      energy new              =    -161.4284071569 ryd

      CASE: energy_new > energy_old

      new trust radius        =       0.0000032530 bohr


      WARNING :  something is going wrong
---------------------
Then the scf cycle continues ,but the bfgs step does not.


Please give me some advice.Thank you in advance!

The input file is as follows:


  &CONTROL
                        title = 'A--0.01-' ,
                  calculation = 'relax' ,
                 restart_mode = 'from_scratch' ,
                       outdir = '/root/tmp/' ,
                   pseudo_dir = '/root/software/pwscf/espresso/pseudo/' ,
                       prefix = 'A--0.01-' ,
                        nstep = 150 ,
                      tstress = .true. ,
                      tprnfor = .true. ,
                      tefield = .true. ,
  /
  &SYSTEM
                        ibrav = 6,
                    celldm(1) = 10.2,
                    celldm(3) = 5,
                          nat = 19,
                         ntyp = 2,
                      ecutwfc = 25 ,
                      ecutrho = 120 ,
                  occupations = 'smearing' ,
                      degauss = 0.005 ,
                     smearing = 'gaussian' ,
                         edir = 3 ,
                      emaxpos = 0.71 ,
                       eopreg = 0.01 ,
                         eamp = 0.01 ,
  /
  &ELECTRONS
             electron_maxstep = 100,
                     conv_thr = 1.0d-8 ,
                  mixing_mode = 'plain' ,
                  mixing_beta = 0.1 ,
                  mixing_ndim = 16,
              diagonalization = 'cg' ,
  /
  &IONS
                 ion_dynamics = 'bfgs' ,
                      upscale = 10 ,
      potential_extrapolation = 'wfc2' ,
  /
ATOMIC_SPECIES
    Si   28.08600  Si.pz-vbc.UPF
     N   14.00670  N.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
    Si      0.000000000    0.000000000    5.397600000
    Si      2.698800000    2.698800000    5.397600000
    Si      1.349400000    4.048200000    4.048200000
    Si      4.048200000    1.349400000    4.048200000
    Si      1.349400000    4.048200000    9.445800000
    Si      4.048200000    1.349400000    9.445800000
    Si      0.000000000    2.698800000    2.698800000    0  0  0
    Si      2.698800000    0.000000000    2.698800000    0  0  0
    Si      0.000000000    2.698800000    8.096400000
    Si      2.698800000    0.000000000    8.096400000
    Si      1.349400000    1.349400000    1.349400000    0  0  0
    Si      4.048200000    4.048200000    1.349400000    0  0  0
    Si      1.349400000    1.349400000    6.747000000
    Si      4.048200000    4.048200000    6.747000000
    Si      0.000000000    0.000000000    0.000000000    0  0  0
    Si      2.698800000    2.698800000    0.000000000    0  0  0
    Si      0.000000000    0.000000000   10.795200000
    Si      2.698800000    2.698800000   10.795200000
     N      2.698800000    2.698800000   16.795200000    1  1  0
K_POINTS automatic
   4 4 1   1 1 1



xywu
xywu at imr.ac.cn





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