Aff `get_coefficients_by_name` intended behavior?

[thisiscam]

import islpy
aff = islpy.Aff("[N] -> { [x] -> [x+1] } ")
aff.get_coefficients_by_name(dimtype=None)

gives

isl_aff.c:763: output/set dimension does not have a coefficient

According the doc, setting dimtype to None should produce the coefficients for all dimensions?
I digged a little, in the generated _isl.py,

_CHECK_DIM_TYPES = [
        dim_type.in_, dim_type.param, dim_type.set]

which is used by obj_get_coefficients_by_name to retrieve the coefficients. When does Aff has a set dimension? Is this a bug or intended behavior?

[thisiscam]

Btw, to the maintainer of this repo: I have no intention to flood this repo's issues (I felt guilty for the fact that the most recent issues were all opened by me). islpy is a wonderful library! I really appreciate the effort put into this interface, and just hope that some of my nitpicks can help in its development. Thanks for the work!

[inducer]

>>> import islpy
>>> aff = islpy.Aff("[N] -> { [x] -> [x+1] } ")
>>> aff.get_dim_name(islpy.dim_type.param, 0)
'N'
>>> aff.get_dim_name(islpy.dim_type.in_, 0)
'x'
>>> 

I'd be OK special-casing Aff in get_coefficients_by_name(None) to avoid triggering the issue. Asking about the "out" dimension of an Aff doesn't make much sense IMO.

[inducer]

Also, no worries about opening multiple issues in quick succession. It's good to know someone is finding this useful. :)