fix_modify AtC kernel <type> <parameters>
- type (keyword) = step, cell, cubic_bar, cubic_cylinder, cubic_sphere, quartic_bar, quartic_cylinder, quartic_sphere 
 
- parameters :
 step = radius (double)
 cell = hx, hy, hz (double) or h (double)
 cubic_bar = half-width (double)
 cubic_cylinder = radius (double)
 cubic_sphere = radius (double)
 quartic_bar = half-width (double)
 quartic_cylinder = radius (double)
 quartic_sphere = radius (double)
 
fix_modify AtC kernel cell 1.0 1.0 1.0 fix_modify AtC kernel quartic_sphere 10.0 
Must be used with the hardy AtC fix 
 For bar kernel types, half-width oriented along x-direction 
 For cylinder kernel types, cylindrical axis is assumed to be in z-direction 
 ( see fix atc command ) 
No default