resolution = 100
xarray = np.linspace(0, 0.25, num=resolution)
yarray = np.linspace(0, 1, num=resolution)
x, y = np.meshgrid(xarray, yarray, copy=False)
A = fwp(x, y, a)
A[A <= 0] += 1
B = np.fliplr(A)
AB = np.hstack((B, A))
Setting labels manually in matplotlib contour-plot wrong