iFit/structure_factor

 iData_Sqw2D: structure_factor: compute the structure factor
  The structure factor is the integral of the dynamic structure factor along
  the energy axis. It is representative of the material structure.
  Its Fourier transform is the pair distribution function g(r).

  This function is basically a call to trapz(s,1)

 References: Fischer, Barnes and Salmon, Rev Prog Phys 69 (2006) 233

 syntax:
   sq = structure_factor(s)

 input:
   s:  Sqw data set e.g. 2D data set with w as 1st axis (rows, meV), q as 2nd axis (Angs-1).
 output:
   sq: S(q) data set

 Example: sq = structure_factor(iData_Sqw2D('SQW_coh_lGe.nc'));

 See also: trapz, iData/trapz
 (c) E.Farhi, ILL. License: EUPL.