'Compute x^T F x for all correspondences,
return error for each transformed point.'

def get_error(self, data, F):

    data = data.T
    x1 = data[:3]
    x2 = data[3:]
    Fx1 = dot(F, x1)
    Fx2 = dot(F, x2)
    denom = ((((Fx1[0] ** 2) + (Fx1[1] ** 2)) + (Fx2[0] ** 2)) + (Fx2[1] ** 2))
    err = ((diag(dot(x1.T, dot(F, x2))) ** 2) / denom)
    return err
