3.11.2 update

void update(float *coord)

Convert the given internal coordinates to Cartesian x, y, z coordinates in-place. On input, coord[0] should contain the distance to the previous atom position or location, coord[1] the angle to the two previous locations and coord[2] the signed torsion to the previous three locations. Upon return, coord[0] contains the x coordinate, coord[1] the y coordinate and coord[2] the z coordinate in Cartesian space.