SHCoefficientsToGFA  [--returnparameterfile <std::string>]
                        [--processinformationaddress <std::string>] [--xml]
                        [--echo] [--debug] [--power <double>] [--]
                        [--version] [-h] <std::string> <std::string>


   --returnparameterfile <std::string>
     Filename in which to write simple return parameters (int, float,
     int-vector, etc.) as opposed to bulk return parameters (image,
     geometry, transform, measurement, table).

   --processinformationaddress <std::string>
     Address of a structure to store process information (progress, abort,
     etc.). (value: 0)

     Produce xml description of command line arguments (value: 0)

     Echo the command line arguments (value: 0)

     debug (value: 0)

   --power <double>
     Power argument. If the power is 2, we have closed form. For other
     power number, we use a numerical fitting of the powered spherical
     function. (value: 1)

   --,  --ignore_rest
     Ignores the rest of the labeled arguments following this flag.

     Displays version information and exits.

   -h,  --help
     Displays usage information and exits.

     (required)  Input image file where each voxel contains a vector of SH

     (required)  Output image file where each voxel contains a scalar GFA.

   Description: calculate GFA from SH coefficients.


   SHCoefficientsToGFA eap_r0.015.nii.gz eap_r0.015_gfa.nii.gz


   Tuch, David S. 'Q‐ball imaging.' Magnetic resonance in medicine 52.6
   (2004): 1358-1372.

   Descoteaux, Maxime, Elaine Angelino, Shaun Fitzgibbons, and Rachid
   Deriche. 'Regularized, fast, and robust analytical Q‐ball imaging',
   Magnetic resonance in medicine 58, no. 3 (2007): 497-510.

   Author(s): Jian Cheng (

   Acknowledgements: Thank you everyone.