/*---------------------------------------------------------------------------------
  Title: UserFs.txt
  Purpose: Define F(s)
  Author: P. Kano, M. Brio
  Date: May 9, 2011
  
  Comment: 
  User defines the function Fs to invert here.
  F(s) Must be written in a way that it can be implemented in C/C++ or CUDA-C.
  This may require explicit definition of functions of complex variables.
  
  This function is included directly into the CUDA kernal wfnsampleFS.cu
  A device function for F(s) could also be used.
 ----------------------------------------------------------------------------------*/
  
 
  /*Example C: 
  F(s) = 1/(s*(s*s + 9/25))
  f(t) = 1/( (25/9)*(1-cos(3*t/5)) ) 
  f(1) = 0.4851788474
  ---------------------------------------*/
  Fs = make_cuDoubleComplex(0.36,0.0);
  precComp Ssquared = cuCmul(s,s);
  Fs = cuCadd(Ssquared,Fs);
  Fs = cuCmul(Fs,s);
  precReal Magnitude = cuCabs(Fs);
  Fs.x = Fs.x/(Magnitude*Magnitude);
  Fs.y = -1*Fs.y/(Magnitude*Magnitude);
 