24 How do I calculate the elastic constants as a function of temperature?

This is a two step calculation. First use what='elastic_constants_t'. This option computes the elastic constants for all the geometries used by what='mur_lc_t' and saves them in the directory elastic_constants. In the second step use the same input for pw.x and run again thermo_pw using what='mur_lc_t' and copying in your working directory the directory elastic_constants obtained in the previous step. Presently the code computes the temperature dependent elastic constants only within the ``quasi-static'' approximation, meaning that it interpolates the elastic constants found in the first step at the geometry that minimizes the Helmholtz (or Gibbs at finite pressure) free energy. The plot of the elastic constants will be found in output_ahar.el_cons.ps. Note that this approach used with the option lmurn=.FALSE. can calculate the thermodynamic properties of non-cubic solids.