implemented .inputs and .outputs properties for NIRGraphs

[matjobst]

Implementation of Issue #29 "Add .inputs and .outputs properties to NIRGraph"

[Jegp]

Really nice work @matjobst. I particularly like how we're not adding any data to the existing declarations, but just using the existing data to provide convenient functionality.

There are a few linter errors, but that may just be a matter of rebasing to main?

But, before we merge, I suggest we resolve the conversation here: #28

[Jegp]

I get a warning from ruff that the line is too long. May I suggest either adding pre-commit as mentioned in the docs or maybe bumping the minimum line length to something more than 88?

[Jegp]

Or maybe it's just a matter of rebasing onto main?

[matjobst]

I pushed this failing version now to showcase one issue that came up:
In the tests (test_ir.py), line 155 I check the following:
assert ir.nodes["in2"] in ir2.nodes["inner"].inputs.values()
However, that fails with "ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()"

The reason for that is that dataclasses generate a default comparison __eq__() function which compares all attributes of the class, but does not understand how to properly compare the arrays. For the case of the Input node, the resulting __eq__() does something like this:

def __eq__(self, other):
    return self.shape == other.shape

Since the .shape is typically an array, it would rather need to do something like:

def __eq__(self, other):
    return (self.shape == other.shape).all()

However I am still not sure whether we want that behavior. Because that means that:

a = nir.Input(shape=np.array([1]))
b = nir.Input(shape=np.array([1]))
a == b   # True

This could be avoided by having a name in each node.
See also Issue #36 .

[Jegp]

#50 stabilizes how input and output types are treated, so now would be a good time to merge this, I believe. @matjobst, would you have time to fast-forward this branch so we can proceed?

[matjobst]

This is also a proposed fix to #36
The equality of all nodes is replaced by identity.

[Jegp]

I think this is a solid implementation and fulfills the specs. Nice work!

Please go ahead and squash + merge when ready :)