Computation of magnetic field defined by hysteresis curve

Question

With given ferromagnetic cylinder we known its hysteresis curve. Then we use coils to create magnetic field. How do we compute the overall magnetic field?

1. I computed the magnetic field on the boundary of this cylinder.

2. Then at each point of the cylinder I subtracted magnetization according to the hysteresis curve.

3. Then I multiplied vector of magnetization with small volume.

4. Finally I computed magnetic field from magnetic dipole.

Is this approach correct? Any comments are welcome. Note: the material is isotropic.