Matlab files in this directory:

vb_average_radius	return average distance between center point and satellites
vb_convertSphereByRadius	convert spherical coordinates to adjust to specified radius
vb_get_spherical_harmo	return spherical harmonics value by using legendre index table
vb_legendre_basis	Calculate Legendre basis function (Normalized)
vb_spherical_grad	spherical gradient dot
vb_spherical_grad_F	calculate gradient of spherical harmonics
vb_spherical_grad_G	spherical harmonics gradient G external current
vb_spherical_harmo_F	calculate spherical harmonics
vb_spherical_harmo_G	calculate spherical harmonics G
vb_spherical_harmo_V	spherical harmonics V
vb_spherical_harmo_W	spherical harmonics W
vb_spherical_harmo_coef	calculate spherical harmonic coefficient
vb_spherical_harmo_magnetic_field	calculate magnetic field of spherical harmonics