[developers] LKB vs. PET divergences

johnca at sussex.ac.uk johnca at sussex.ac.uk
Wed Feb 16 11:46:50 CET 2005

Quoting Ann Copestake <Ann.Copestake at cl.cam.ac.uk>:

> thanks.  Just to make sure I understand something (I've just checked
> the code) 
> - when the process is iterated for the new glbtypes, you just iterate
> it on 
> pairs of new types and you don't add any further bits.  So this is
> just for 
> the case where two distinct glb types have a set of descendants in
> common 
> which doesn't correspond to any existing type.

Yes, that's right.

> BTW, when I looked at the code, I couldn't see why in
> check-type-table the 
> partitions were being sorted.  I think this may be a hang-over from
> the old 
> code?  This isn't going to give a unique ordering on partitions since
> there 
> may be two the same length, so the glb numbering won't necessarily be
> consistent.

You're right, it won't necessarily work if there are two partitions the same
size. But I think I remember that this partitioning helped with the
efficiency of glb computation so that's really why it's still there.


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