iirgroup
========

group delay Lp IIR filter optimization



Calling Sequence
~~~~~~~~~~~~~~~~


::

    [lt,grad]=iirgroup(p,r,theta,omega,wt,td)
    [cout,grad,ind]=iirlp(x,ind,p,[flag],lambda,omega,ad,wa,td,wt)




Arguments
~~~~~~~~~

:r vector of the module of the poles and the zeros of the filters
: :theta vector of the argument of the poles and the zeros of the
  filters
: :omega frequencies where the filter specifications are given
: :wt weighting function for and the group delay
: :td desired group delay
: :lt, grad criterium and gradient values
:



Description
~~~~~~~~~~~

optimization of IIR filters for the Lp criterium for the the group
delay. (Rabiner & Gold pp270-273).