This function computes the potential energy of a mass distribution. It directly sums the interactions between all particles, so it is exact (to within machine precision) but scales as N^2. The poten_tree routine is slightly (1%) less accurate, but scales as NlogN. This routine is faster for <<10^4 particles, because the algorithm is simpler. Furthermore, this routine can calculate the potential in any dimension, whereas poten_tree is restricted to 3 dimensions.
The potential energy of the system. It is assumed that G=1, so that PE = sum_i (sum j > i (m_i * m_j / r_ij) )
- pos in required
A [ndim, n] array of n-dimensional particle locations
- mass in required
A n element vector of masses
|Modifcation date:||Mon Jul 12 19:53:21 2010|