Missing symbol in NXsample

[rayosborn]

The temperature field in the NXsample NXDL file has dimensions set as "anyRank". This is not defined as a symbol and does not appear in any of the other NXDL files or XSD files. I would suggest that it should be removed.

I'm not sure of the policy for symbols. I presume their only purpose is to ensure that fields that should have matching dimensions should share the same values. Apart from 'n_comp', all the other symbols only appear in a single field and so appear to be redundant. If it is required that the field is not a scalar, perhaps we should specify a tag of rank=NX_ANY, although that symbol is only currently used for units.