Validate input tree

[ElDeveloper]

The input tree should be validated and raise an appropriate exception in these cases:

• duplicated tip ids are present.
  - [ ] unrooted trees are passed.
  - [ ] no branch lengths present in the tree, we should come to an agreement on what distance should be returned in this case.

[wasade]

@ElDeveloper, reviewing this right now. I agree with a check for duplicate tip IDs. I don't think requiring rooted trees makes sense as that disallows the use of taxonomies since they are not bifurcating, and the original implementations would support computation on these trees anyway. With missing branches, we've historically (including the original implementations of UniFrac) defaulted to a 0 value.

[ElDeveloper]

That makes sense.

…

On (Apr-29-18|13:35), Daniel McDonald wrote: @ElDeveloper, reviewing this right now. I agree with a check for duplicate tip IDs. I don't think requiring rooted trees makes sense as that disallows the use of taxonomies since they are not bifurcating, and the original implementations would support computation on these trees anyway. With missing branches, we've historically (including the original implementations of UniFrac) defaulted to a 0 value. -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #35 (comment)

[wasade]

This is still a nice to have, but validation needs to be structured so it is optional. Leaving open but not addressing yet