var G = 6.67e-11;
    var force = G * mass1 * mass2 / distance * distance;
    return force;

  % pointMatrixGravity - Calculates the gravitational force and torque on a
  % point mass due to a matrix of point masses.
  % 
  %   [force, torque]=pointMatrixGravity(array1,array2)
  % 
  %   Inputs:
  %       array1 - 3xN array of point masses
  %       array2 - 3xN array of point masses
  %   Outputs:
  %       force - 3x1 array of gravitational force
  %       torque - 3x1 array of gravitational torque
  % 
  %   Author: David J. R. MacKay,
  %   email:

function force=Gmmr2Array(mass1, mass2) {

    var G = 6.67408e-11;

    var m1 = mass1;

    var m2 = mass2;

    var r = 1;

    var force = G \* m1 \* m2 / (r \* r);

    return force;

function [force, torque]=pointMatrixGravity(array1,array2) {

    var G = 6.67408e-11;

    var m1 = array1(1);

    var m2 = array2(1);

    var r = norm(array1(2:4)-array2(2:4));

    var force = G \* m1 \* m2 / (r \* r);

    var torque = cross(array1(2:4)-array2(2:4), force);

    return [force, torque];

}

For pointMatrixGravity: https://gist.github.com/ridiculousfish/af05137a4090e92de3a97...