fix_modify AtC gradients <add | delete> <list_of_fields> 
 fix_modify AtC gradients add temperature velocity stress  
  fix_modify AtC gradients delete velocity  
 
Requests calculation and ouput of gradients of the fields from the transfer class. These gradients will be with regard to spatial or material coordinate for eulerian or lagrangian analysis, respectively, as specified by atom_element_map (see fix_modify AtC atom_element_map )
Must be used with the hardy/field type of AtC fix ( see fix atc command )
No gradients are calculated by default
 1.6.1
 1.6.1