# NotImplementedError: Echelon form not implemented over 'Ring of integers modulo 16'

Asking for the echelon form of a matrix over `Zmod(16)`

fails as follows:

```
sage: a = matrix(Zmod(16), [[1, 1], [1, 1]])
sage: a.echelon_form()
Traceback (most recent call last):
...
NotImplementedError: Echelon form not implemented over 'Ring of integers modulo 16'.
```

Is this error meanwhile remediated?

This error also occurs when trying to calculate `eigenspaces_right`

and or `right_kernel`

of a matrix defined with elements in `Zmod(16)`

or `IntegerRing(16)`

.

Please provide a code example.

You could try

`a._echelon_classical()`

or`a._echelon_in_place_classical()`

. (Try`a._echelon`

and then hit the TAB key to see some options, not all of which will work.)There is also

`a._right_kernel_matrix_over_integer_mod_ring()`

. I don't see an obvious option for eigenspaces.