CoveringRadius
==============

.. code-block:: none

  % Calculate the covering radius of the given samples. 
  %
  % USAGE:
  %    radius = CoveringRadius(grad)
  %    radius = CoveringRadius(grad, ind)
  %
  % INPUT
  %    grad     :  Nx3 matrix, each row is a point in sphere.
  %    ind      :  If it is given, calculate the minimal distance between 
  %                the ind-th sample and the other samples in grad.
  %
  %
  % OUTPUT
  %    radius   :  covering radius, i.e., the minimal spherical distance between any two samples.
  %
  %
  % References: 
  %   1.  http://mathworld.wolfram.com/SphericalCode.html
  %   2. "Single- and Multiple-Shell Uniform Sampling Schemes for Diffusion MRI Using Spherical Codes", 
  %       Jian Cheng, Dinggang Shen, Pew-Thian Yap, Peter J. Basser, IEEE Transactions on Medical Imaging, 2017.  
  %   3. "Designing Single- and Multiple-Shell Sampling Schemes for Diffusion MRI Using Spherical Code", 
  %       Jian Cheng, Dinggang Shen, Pew-Thian Yap, MICCAI 2014.  
  %   4. "Novel single and multiple shell uniform sampling schemes for diffusion MRI using spherical codes", 
  %       Jian Cheng, Dinggang Shen, Pew-Thian Yap, Peter J. Basser, MICCAI 2015.  
  %
  % Copyright (c) 2014, Jian Cheng <jian.cheng.1983@gmail.com>
  %