function [b1, b2, U, V]  = piro_band(A, sym, blks)
%
% piro_band reduces a band matrix (full/sparse) to an upper bidiagonal matrix
% using blocked and interleaved Givens rotations. 
%
% Usage :
% [b1, b2, U, V] = piro_band(A)
% [b1, b2, U] = piro_band(A)
% [b1, b2] = piro_band(A)
%
% or 
% [b1, b2, U, V] = piro_band(A, sym, blksize)
% [b1, b2, U] = piro_band(A, sym, blksize)
% [b1, b2] = piro_band(A, sym, blksize)
%
% sym and blocksize are optional input argument. sym=1 for symmetric matrices,
% blksize is an array of 4 for the upper and lower block sizes respectively. A
% block size that is equivalent to a householder will be [ub-1 1 lb 1] where ub
% and lb are the upper and lower bandwidths. A can be real/complex.
%

%   Copyright 2009, Sivasankaran Rajamanickam, Timothy A. Davis
%   http://www.cise.ufl.edu/research/sparse

error ('piro_band is missing \n')