density_summation_fcn Abstract Interface

abstract interface
private subroutine density_summation_fcn(particle, pairs, n)

Type	Intent		Name
type(particle_type),	intent(inout)	::	particle	particle 区域
type(nnps_pairs_type),	intent(in)	::	pairs	particle pairs 粒子对
integer,	intent(in)	::	n	实弹性粒子数, numbers(1)

Density summation
密度求和