[Mitgcm-support] 1.D0 in r1 code

[mitgcm-support at dev.mitgcm.org]

Alistair, Jean-Michel, Patrick, Me:

We seem to have a rash of in-line .D numbers in the code.

e.g.

          4.D0*(uVel(...))

etc...

They are all over the place in the gad_ and mom_ packages.
This is going to cause problems on some machines e.g. T3E,
IBM, Cray, NEC.

Can somebody explain why they are there? I thought we hade settled
on using _d most of the time. Then for people who refuse to use _d
we were having symbols like "four". Is this a problem?

Unless we do this properly, getting bit reproducible results over machines
will become a nightmare and we will be fielding complaints about code
performance
on certain platforms.

Chris