Wrong current answers on macOS

[rpep]

Running the test under identical conditions with the latest checked out master branch on my Macbook gives the incorrect answer on the STT calculations.

_________________________________________________________________________________________________________ test_stt_dw _________________________________________________________________________________________________________

    @pytest.mark.slow
    def test_stt_dw():
        # We will crate a mesh with 1000 elements of 2x2x2 nm
        # in the x direction, and 1 along y and z
        # (so we have a 1D system)
        mesh = Mesh(nx=1000, ny=1, nz=1,
                    dx=2, dy=2, dz=2.0,
                    unit_length=1e-9)

        # Relax the initial state. It will save the last state
        # to the m0.npy file
        relax_system(mesh)

        m0_z = load_mz_npy('m0.npy')

        x = np.arange(len(m0_z))
        index_max = np.argmax(np.abs(m0_z))

        assert x[index_max] == 225
        assert np.abs(m0_z[index_max] - 0.705740362679) < 1e-8

        # Excite the system for 1.5 ns
        excite_system(mesh, 1.5, 151)

        m0_z = load_mz_npy('dyn_npys/m_100.npy')
        x = np.arange(len(m0_z))
        # Check that the DW is at the 242th x-position in the 100th snapshot
        print(x[np.argmax(np.abs(m0_z))])
>       assert x[np.argmax(np.abs(m0_z))] == 242
E       assert 972 == 242

../../../Git/fidimag/tests/test_stt_dw.py:161: AssertionError

I noticed this by looking at the current driven Skyrmion notebook; the skyrmion was moving faster than it should have been...