def positions(self):
        """Initial position for each particle. Shape (N, 3, 1)."""
        return np.vstack([p.r0 for p in self]).reshape(len(self), 3, 1)
def positions(self):
        """Initial position for each particle. Shape (N, 3, 1)."""
        return np.vstack([p.r0 for p in self]).reshape(len(self), 3, 1)
def positions ( self ) : return np . vstack ( [ p . r0 for p in self ] ) . reshape ( len ( self ) , 3 , 1 )
Initial position for each particle. Shape (N, 3, 1).
Initial position for each particle . Shape ( N 3 1 ) .