4.18 what='mur_lc_elastic_constants'

As what='scf_elastic_constants' but the calculation is made at the geometry that minimizes the energy. The energy minimization is done as described for what='mur_lc'. With this option the pressure control is active. You can specify a finite pressure and the enthalpy is minimized instead of the energy to find the equilibrium structure. Note however that if the minimum is distant from the starting configuration its associated error can be large, larger for the quadratic than for the Murnaghan interpolation. An example of the use of this option can be found in example13.
One additional input variable controls this option.

do_scf_relax : if .TRUE. the code makes a self-consistent relax calculation at
               the equilibrium geometry to find the optimized atomic 
               coordinates, before computing the elastic constants.
               This step is needed only for solids that have internal
               degrees of freedom in the unstrained configuration. 
               If .FALSE. the coordinates of the input geometry are strained 
               uniformly to the equilibrium geometry.
               Default: logical .FALSE.

Number of tasks for this option: Maximum between the number of tasks needed by the what='mur_lc' option and the number of tasks needed for the what='scf_elastic_constants' option.