POLPARAMS is the jSpectral module of jLab.

  POLPARAMS  Spectral matrix polarization parameters.
 
    [E,P,ALPHA,BETA]=POLPARAMS(S) where S is a 2x2 spectral matrix returns
    the energy E and the polarization paramters P, ALPHA, and BETA.
 
    If S is a 2 x 2 x M matrix, then all output variables are Mx1 column
    vectors.  More generally, if S is 2 x 2 x M x ... N, then all output
    variables are M x ... N.
   
    [...]=POLPARAMS(SXX,SXY,SXY) also works. In this case all input 
    variables are matrices of the same size. 
   
    [E,P,ALPHA,BETA,PREAL,GAMMA]=POLPARAMS(S) also optionally retuns the
    polarization ratio of the real part of S and the coherence GAMMA.
 
    See also SPECDIAG.
 
    Usage:  [E,p,alpha,beta]=polparams(s);
            [E,p,alpha,beta,preal,gamma]=polparams(s);
            [E,p,alpha,beta,preal,gamma]=polparams(sxx,syy,sxy);
    _________________________________________________________________
    This is part of JLAB --- type 'help jlab' for more information
    (C) 2004--2012 J.M. Lilly --- type 'help jlab_license' for details