Function: spreadop
SPREADOP  Spreading operator
  Usage: h=spreadop(f,c);

  SPREADOP(f,c) applies the operator with spreading function c to the
  input f. c must be square.

  SPREADOP(f,c) computes the following for c of size L xL:

             L-1 L-1 
    h(l+1) = sum sum c(m+1,n+1)*exp(2*pi*i*l*m/L)*f(l-n+1)
             n=0 m=0

  where l=0,...,L-1 and l-n is computed modulo L.

  The combined symbol of two spreading operators can be found by using
  tconv. Consider two symbols c1 and c2 and define f1 and f2 by:

    h  = tconv(c1,c2)
    f1 = spreadop(spreadop(f,c2),c1);
    f2 = spreadop(f,h);

  then f1 and f2 are equal.


  References:
    H. G. Feichtinger and W. Kozek. Operator quantization on LCA groups. In
    H. G. Feichtinger and T. Strohmer, editors, Gabor Analysis and
    Algorithms, chapter 7, pages 233--266. Birkhauser, Boston, 1998.
    

Url: http://ltfat.github.io/doc/operators/spreadop.html

See also: tconv, spreadfun, spreadinv, spreadadj.

Package: ltfat