[Thermo_pw-forum] nonstoichiometric compounds

[Andrea Dal Corso]

The energy algortitm works only at zero strain. It can deal with a  
finite pressure, but not with a finite strain. So for the moment the  
elastic constants as a function of temperature cannot be calculated  
with this
algorithm.

Thank you for reporting, I will add a sentence in the user-guide to  
explain this point.

Andrea



Quoting Gunnar Palsson <gunnar.karl at gmail.com>:

> Dear Andrea
>
> I attempted to calculate the elastic constants as a function of  
> temperature with thermo_pw, which works completely fine with the  
> ‘standard’ algorithm.
> I wanted to compare the results using the ‘energy’ algorithm and I  
> receive the error below. I managed to reproduce the error using your  
> example 13, but changing mur_elastic_constants -> elastic_constants_t.
>
> snippet of the output:
>    
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>      Computing the thermodynamic properties from elastic constants
>      Writing on file therm_files/output_therm.dat_debye.g1
>    
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
>
> ********************************************************************************
>      Computing geometry     2
>      Computing the elastic constant for celldm
>          10.05000     0.00000     0.00000     0.00000     0.00000     0.00000
>      Unit cell volume   253.76878
>      Cartesian axes
>      site n.     atom                  positions (alat units)
>          1           Si  tau(   1) = (   0.0000000   0.0000000   0.0000000  )
>          2           Si  tau(   2) = (   0.2500000   0.2500000   0.2500000  )
> ********************************************************************************
>
> mpprun info:   Job terminated with error
>
> forrtl: severe (151): allocatable array is already allocated
> Image              PC                Routine            Line        Source
> thermo_pw.x        0000000000F9FF7B  Unknown               Unknown  Unknown
> thermo_pw.x        0000000000461DB0  set_elastic_cons_         318   
> set_elastic_cons_work.f90
> thermo_pw.x        0000000000421EA7  initialize_thermo         304   
> initialize_thermo_work.f90
> thermo_pw.x        0000000000407DC2  MAIN__                    345   
> thermo_pw.f90
> thermo_pw.x        000000000040741E  Unknown               Unknown  Unknown
> libc.so.6          00002AF8F257ED1D  Unknown               Unknown  Unknown
> thermo_pw.x        0000000000407329  Unknown               Unknown  Unknown
>
>
>
> cat > thermo_control << EOF
>  &INPUT_THERMO
>   what='elastic_constants_t',
>   frozen_ions=.FALSE.,
>   elastic_algorithm='energy',
>  /
> EOF
>
> cat > v.in << EOF
>  &control
>     calculation = 'scf'
>     restart_mode='from_scratch',
>     prefix='v',
>     pseudo_dir = '$PSEUDO_DIR/',
>     outdir='$TMP_DIR/'
>  /
>  &system
>     ibrav=  2,
>     celldm(1) =10.20,
>     nat= 2,
>     ntyp= 1,
>     ecutwfc=24.0,
>  /
>  &electrons
>     conv_thr =  1.0d-8
>  /
> ATOMIC_SPECIES
>  Si  28.086  Si.pz-vbc.UPF
> ATOMIC_POSITIONS (alat)
>  Si 0.00 0.00 0.00
>  Si 0.25 0.25 0.25
> K_POINTS AUTOMATIC
> 12 12 12 1 1 1
> EOF
>
> Any idea what could be causing this?
>
> Best regards,
> Gunnar