Arguments in update_state need if present.

[dabail10]

I was adding a dvsdtd variable to the update_state call and found this code:

     daidt(i,j,iblk) = (aice(i,j,iblk) - daidt(i,j,iblk)) / dt
     dvidt(i,j,iblk) = (vice(i,j,iblk) - dvidt(i,j,iblk)) / dt
     dvsdt(i,j,iblk) = (vsno(i,j,iblk) - dvsdt(i,j,iblk)) / dt

These are wrapped in an if present(offset), but in my case I only want dvsdtd (dynamic) I don't want the dvsdtt (thermodynamic). It still seems dangerous to rely on offset only here. I would recommend an if present in front of these three.

[apcraig]

I assume, based on the current implementation, that either all the optional arguments are passed or none are. It would be good to have a check at the top of the subroutine to ensure that.

But it sounds like what you're proposing is that the code works with any number of the optional arguments present? offset seems to affect only dagedt, so if dagedt is present, does offset have to be present too?

[apcraig]

#940 addressed this issue. Will close.