iFunc_Sqw4D: dos: compute the density of states (vDOS)
The routine can be used with 4D models to compute the vibrational density of
states (vDOS), aka phonon spectrum.
DOS = dos(s) returns the vibrational density of states (vDOS)
the vDOS and the partials per mode are also stored in the model UserData.
DOS = dos(s, n)
does the same with n-bins on the vDOS (n=100).
'n' can also be a vector of energy values.
DOS = dos(s, n, nQ)
does the same with nQ-bins for the HKL average (n=21)
DOS = dos(s, n, nQ, method)
specifies the method among '4d', 'powder' and 'fast' estimate.
To smooth the resulting distribution, use:
sDOS = smooth(DOS); plot(sDOS);
If the DOS has already been calculated, it is re-used. To force calculation
use a non-0 value or 'force' for 'n'.
input:
s: S(q,w) 4D model (iFunc_Sqw4D)
n: number/vector of energy values (scalar/vector). Optional. Default is nmodes*10
nQ: number of Q-grid binning (integer). Optional. Default is 21
method: optional, can be '4D' (default) or 'powder' or 'fast'
output:
DOS: DOS(w) (1D iData versus energy)
DOS_partials: DOS(w) per mode (1D iData array, versus energy)
See also: iFunc_Sqw4D/max
Example: Sqw=sqw_cubic_monoatomic; D=dos(Sqw);
(c) E.Farhi, ILL. License: EUPL.