Functions in Phonon

Phonon ver. 4.28 contains all options of Phonon, ver. 4.24.
The performance of Phonon, ver. 4.28, with respect to ver. 4.24, is greatly improved. In particular, for the "Hellmann-Feynman/DO Report" option the computing CPU time is shortened by a factor of 10 - 100, depending on the supercell size and symmetry.
There are now two versions to calculate the force constants from Hellmann-Feynman forces. First, permits to find the force constants from single (+/-) displacements of non-equivalent atoms of the crystal unit cell. Second, allows to supplement the Hellmann-Feynman file by forces generated by simultaneous displacement of many atoms of supercell, for example those which form a specially interesting phonon mode.
There is about 140 predefined models with realistic force constants, or Hellmann-Feynman forces.