registration: changed value_type from float to double to increase precision (and speed for small number multiplication at convergence)
registration: changed value_type from float to double to increase precision (and speed for small number multiplication at convergence)

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3