pwtools.pydos.fvacf

pwtools.pydos.fvacf(vel, m=None, method=2, nthreads=None)[source]

Interface to Fortran function _flib.vacf(). Otherwise same functionallity as pyvacf(). Use this for production calculations.

Parameters:

  • vel (3d array, (nstep, natoms, 3)) – Atomic velocities.

  • m (1d array (natoms,)) – Atomic masses.

  • method (int) –

    1 : loops
    2 : vectorized loops

  • nthreads (int ot None) – If int, then use this many OpenMP threads in the Fortran extension. Only useful if the extension was compiled with OpenMP support, of course.

Returns:

c – VACF

Return type:

1d array (nstep,)

Notes

Fortran extension:

$ python -c "import _flib; print(_flib.vacf.__doc__)"
vacf - Function signature:
  c = vacf(v,m,c,method,use_m,[nthreads,natoms,nstep])
Required arguments:
  v : input rank-3 array('d') with bounds (natoms,3,nstep)
  m : input rank-1 array('d') with bounds (natoms)
  c : input rank-1 array('d') with bounds (nstep)
  method : input int
  use_m : input int
Optional arguments:
  nthreads : input int
  natoms := shape(v,0) input int
  nstep := shape(v,2) input int
Return objects:
  c : rank-1 array('d') with bounds (nstep)
Shape of vel: The old array shapes were (natoms, 3, nstep), the new is

(nstep,natoms,3). B/c we don’t want to adapt flib.f90, we change vel’s shape before passing it to the extension.

See also

pwtools._flib, vacf_pdos()