[Mitgcm-support] exch_xz, exch_yz

[mitgcm-support at dev.mitgcm.org]

Hi Patrick,

 Would it be very hard to impose an exchange after 
OBC application rule? Looked at _xz, _yz. You did 
a good job but I see two probs.

 1. How does this help for general OBCS, which might
    not orient with grid.

 2. For cube there are mapping YZ <-> XZ, YZ <-> -XZ
    etc... for certain connections. Enabling this 
    would require further effort.

 Both 1. and 2. are fixed by imposing a post-OBC exchange.
 Plus it makes the merge easier! And it means we can
 survive without extending the exch() operator for a
 while longer.

 Alistair what do you think?

Chris