Unary force container

operator ()

Synopsis:

Called by the granular system to compute the acceleration of particle i due to unary forces acting on it

Arguments:

size_t i

index of the particle that is being accelerated

std::vector<fielv_value_t> const & x

const reference to the position buffer

std::vector<fielv_value_t> const & v

const reference to the velocity buffer

std::vector<fielv_value_t> const & theta

const reference to the orientation buffer

std::vector<fielv_value_t> const & omega

const reference to the angular velocity buffer

real_t t

simulation time

Return value:

std::pair<field_value_t, field_value_t>

translational acceleration and angular acceleration of particle i due to unary forces acting on it