Here's one for the regular inv op comparing eigen_fields:
```
(mismatch 81.2706261758%)
 x: array([[  1.11022302e-16,  -3.33066907e-16,   6.66133815e-16, ...,
          7.11191463e-02,   4.20858888e-02,  -1.56025929e-01],
       [ -1.11022302e-16,  -2.22044605e-16,  -4.99600361e-16, ...,...
 y: array([[  0.00000000e+00,  -1.61600866e-08,   5.17012175e-08, ...,
         -7.11221024e-02,  -4.20904085e-02,  -1.56029537e-01],
       [ -0.00000000e+00,   6.58691306e-08,  -7.62367804e-08, ...,...
```
So, it looks like it might work with abs() and 2 dec places. I'll check...