fitfc

Fit Stiffness VS Length transferable force constants 2.81, by Axel van de Walle
  -f          Fit force constants (otherwise, generate pertubations)
 -si=[string] Input file defining the ideal structure (default: str.out)
 -sr=[string] Input file defining the relaxed structure (default: str_relax.out)
 -er=[real]   Minimum distance between displaced atoms
 -fr=[real]   Force constant range
 -dr=[real]   Displacement of the perturbed atom (default: 0.2)
 -ms=[real]   Strain of the maximum volume sampled (default: 0.01)
 -ns=[int]    Number of volume sample (default: 2)
-nrr          Do not rerelax structures at each new volume
-ncs          No check for singular matrix in fit
 -sf=[string] Extra strain file
  -m=[string] Input file defining the atomic masses (default: ${atatdir}/data/masses.in)
 -T0=[real]   Minimum temperature (default: 0) 
 -T1=[real]   Maximum temperature (default: 2000)
 -dT=[real]   Temperature step (default: 100)
  -P=[real]   Pressure (in MPa, default: 0)
 -kp=[real]   Number of k-points per reciprocal atom (default: 1000)
 -sx=[real]   k-point shift (along 1st recip lat. vect.)
 -sy=[real]   k-point shift (along 2nd recip lat. vect.)
 -sz=[real]   k-point shift (along 3rd recip lat. vect.)
 -df=[string] Phonon dispersion curve calculation input file.
 -hp=[real]   Planck's constant (default in (eV s))
 -kb=[real]   Boltzman's constant (default in eV/K)
-cfk=[real]   Conversion factor for force constants into energy/dist^2 (default: converts eV/A^2 into J/m^2)
 -mu=[real]   Mass units (default: converts a.u. mass into kg)
 -rl=[real]   Robust Length algorithm parameter for soft modes (beta)
 -cP=[real]   Conversion factor from pressure*volume into eV
 -pa          Output free energy per atom instead of per unit cell
 -pe          Print energy in 3rd column of fitfc.out
 -sc=[real]   Correction factor if spectator ion are present (default: 1)
-me0          Subtract energy at 0K
 -fn          Force continuation of calculations even if unstable
 -fu          Find unstable modes
 -gu=[int]    Genenerate unstable modes number n
-mau=[int]    Maximum number of atom per supercell for unstable mode generation
-sfc=[int]    Simplify force constants: 1=streching+bending, 2=symmetric
-sig=[int]    Number of significant digits printed (default: 5)
  -z=[real]   Tolerance for finding symmetry operations (default: 1e-3)
  -h          Display more help