OptimalSamplingMultiSubsetsFromDifferentSets
============================================

.. code-block:: none

  % get K subsets of gradients from corresponding K given gradient sets, such that
  % gradients in each subset are evenly distributed. 
  %
  % USAGE:
  %   [gradCell,grb_result,indexMatrix] = OptimalSamplingMultiSubsetsFromDifferentSets(gradAll, param, grbParam)
  %
  % INPUT
  %   gradAll            :  K gradient matrix cell, where each element is a N_kx3 gradient matrix for a single shell.
  %   param.numSamples   :  Kx1 or 1xK vector which gives number of samples in K subsets
  %   param.w            :  weight for single shell term. 0<w<1. Default value is 0.5.
  %   param.ModelFile    :  string. If set, write the model into a file 
  %
  %   grbParam.start     :  a warm start if provided
  %   grbParam.TimeLimit :  time limit to terminate the program
  %   grbParam.MIPFocus  :  MIPFocus
  %
  % OUTPUT
  %   gradCell           :  Kx1 cell, each element is a gradient matrix.
  %   grb_result         :  output from GUROBI
  %
  %
  % Reference:
  %   1. "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.  
  %   2. "Designing Single- and Multiple-Shell Sampling Schemes for Diffusion MRI Using Spherical Code", 
  %       Jian Cheng, Dinggang Shen, Pew-Thian Yap, MICCAI 2014.  
  %
  % Copyright (c) 2013, Jian Cheng <jian.cheng.1983@gmail.com>
  %