[Pw_forum] bfgs and trust radius

[Vivek Ranjan]

Hi !

I getting the following message :

---------------------------------------------------------------------------
     number of scf cycles    =  14
     number of bfgs steps    =   1

     energy old              =   -1402.7124539122 ryd
     energy new              =   -1402.7077099529 ryd

     CASE: energy_new > energy_old

     new trust radius        =       0.0000480606 bohr

     trust_radius < trust_radius_min

     resetting bfgs history


 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from bfgs : error #         1
     bfgs history already reset at previous step
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     stopping ...
---------------------------------------------------------------------------------

Based on earlier discussions I feel the following are important
parameters, which I have set as  :

     etot_conv_thr = 1.0d-4
     forc_conv_thr = 1.0d-5
&system
     ibrav=  0,
     nat=  31,
     ntyp= 6,
     celldm(1) =  7.2225240402,
     ecutwfc = 35.0,
     ecutrho = 420.0
     occupations='smearing', smearing='mv', degauss=0.05
     nosym=.true.
/
&electrons
     mixing_mode = 'plain'
     mixing_beta = 0.5
     conv_thr =  1.0d-8
     diagonalization = 'david' ,
/
&ions
     upscale=100
/
-------------------------------------------------------------------------

I have faced the above problem several times. But changing one thing or
the another may result in convergence. The above generally happens when
the system is already close to convergence.

I would like to know if it is a good idea to reduce the trust_radius_min
below its present default value set in pwscf ?

Thank you,
Vivek