implement is close operator [FEA]

[luitjens]

we should implement the isclose operator for comparing tensors.

https://www.w3schools.com/python/ref_math_isclose.asp

[cliffburdick]

this is really a reduction I think and can already be implemented with all()

[luitjens]

I think we should have isclose(A,B) which returns a boolean tensor of the same size. Then the reduction can be done with all().

[luitjens]

maybe we implement an isclose pointwise operator and allclose reduction?

[cliffburdick]

Yeah, we probably need two separate versions. I'd imagine almost everyone would want to reduce it afterwards, but look at the larger matrix for statistics or to find where problems are