Fixed wrong DMI vector in C_n class DMI

Author: davidcorteso

fidimag/micro/dmi.py

@@ -151,8 +151,8 @@ def setup(self, mesh, spin, Ms, Ms_inv):
                                         -1., 0, 0,  # +y
                                         0, 0, 0,    # -z
                                         0, 0, 0,    # +z
-                                        1, 0, 0,    # D2 components
-                                        -1, 0, 0,
+                                        -1, 0, 0,    # D2 components
+                                        1, 0, 0,
                                         0, -1, 0,
                                         0, 1, 0,
                                         0, 0, 0,