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revision 1.1255 by dimitri, Mon Apr 26 18:50:14 2010 UTC revision 1.1256 by heimbach, Tue Apr 27 17:43:30 2010 UTC
# Line 4  $Name$ Line 4  $Name$
4      Notes on tags used in MITgcmUV      Notes on tags used in MITgcmUV
5      ==============================      ==============================
6    
7    o adjoint:
8      global_sum_ad was incomplete (noted many times by many people ;)
9      nice description by Jean U. as follows:
10      * allreduce(var) in global_sum.F can be interpreted as
11        reduce(sum) followed by broadcast of sum.  
12      * The adjoint of that is
13        sum(adjoint) followed by broadcast(summed adjoint value)
14        or in other words, allreduce(sum, adjoint vars)
15      We were missing the sum(adjoint)!
16      Benign, except(!) for "global" scalars appearing in tile loops (bi,bj)
17      (noted by J.M. Campin, e.g., in cost_ssh_mean, variable offset).
18      The fix should produce 16-digit accuracy between
19      single-CPU multi-tile (e.g. nSx=2, nPx=1) and
20      multi-CPU single-tile (e.g. nSx=1, nPx-2)
21      We'll probably change this yet again shortly
22  o pkg/icefront  o pkg/icefront
23    - ALLOW_SUBGLACIAL_RUNOFF option adds capability for time-evolving    - ALLOW_SUBGLACIAL_RUNOFF option adds capability for time-evolving
24      specification of addmass array based on a 2D field, which is added      specification of addmass array based on a 2D field, which is added
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