catdomain and catcodomain are both exported from TensorKit, but ?catdomain / ?catcodomain return nothing — there's no docstring attached to either.
The explanation does exist, just not attached to the functions — it's prose on the linear algebra docs page:
If we have two TensorMap{T, S, N, 1} instances t1 and t2 with the same codomain, we can combine them in a way that is analogous to hcat, i.e. we stack them such that the new tensor catdomain(t1, t2) has also the same codomain, but has a domain which is domain(t1) ⊕ domain(t2). Similarly, if t1 and t2 are of type TensorMap{T, S, 1, N} and have the same domain, the operation catcodomain(t1, t2) results in a new tensor with the same domain and a codomain given by codomain(t1) ⊕ codomain(t2), which is the analogy of vcat. Note that the direct sum only makes sense between ElementarySpace objects, i.e. there is no way to give a tensor product meaning to a direct sum of tensor product spaces.
It might be nice to have this (or a shorter version of it) directly on the functions as a docstring, so ?catdomain works without needing to already know where to look for it.
Happy to open a PR adding docstrings based on the existing explanation above, if that's welcome.
catdomainandcatcodomainare both exported from TensorKit, but?catdomain/?catcodomainreturn nothing — there's no docstring attached to either.The explanation does exist, just not attached to the functions — it's prose on the linear algebra docs page:
It might be nice to have this (or a shorter version of it) directly on the functions as a docstring, so
?catdomainworks without needing to already know where to look for it.Happy to open a PR adding docstrings based on the existing explanation above, if that's welcome.