mexReadGrad
===========

.. code-block:: none

  % mexReadGrad:  read gradient files into a matrix
  %
  % Usage:
  %   gradMatrix = mexReadGrad(type, number)
  %   gradMatrix = mexReadGrad('grad.txt')
  %
  % INPUT
  %   type    :  gradient type or gradient file name (.txt)
  %              'elec': gradients from camino based on electrostatic energy.
  %              'tess': gradients based on tessellation.
  %
  %   number  :  if type=='elec', then number means the number of samples.
  %              if type=='tess', then number means tessellation order.
  %
  % OUTPUT
  %   grad    :  Nx3 matrix, each row is a point in sphere.
  %
  % Copyright (c) 2013, Jian Cheng <jian.cheng.1983@gmail.com>
  %