def setUp(self):
        def topo(x):
            return np.sin(x*(2.*np.pi))*0.3 + 0.5

        def function(cell):
            r = cell.center % np.array([0.5]*len(cell.center))
            dist1 = np.sqrt(r.dot(r)) - 0.08
            dist2 = np.abs(cell.center[-1] - topo(cell.center[0]))

            dist = min([dist1,dist2])
            # if dist < 0.05:
            #     return 5
            if dist < 0.05:
                return 6
            if dist < 0.2:
                return 5
            if dist < 0.3:
                return 4
            if dist < 1.0:
                return 3
            else:
                return 0

        M = Mesh.TreeMesh([64,64],levels=6)
        M.refine(function)
        self.M = M
dataset/ETHPy150Open simpeg/simpeg/tests/mesh/test_TreeMesh.py/Test2DInterpolation.setUp/operator `-` -> `%`