-------- Original Message -------- Subject: Fagan Abstract for ICCS submission Date: Wed, 14 Dec 2005 08:59:55 -0600 From: Mike Fagan mfagan@cs.rice.edu Reply-To: mfagan@cs.rice.edu To: Jean Utke utke@mcs.anl.gov, Christian Bischof bischof@rz.rwth-aachen.de
Jean and Chris,
Below is a short title+abstract for my ICCS submission. I will supply full paper late tomorrow (15 Dec 05).
Thanks for your patience.
Best, Mike
P.S. Would 1 of you please email me when you get this? I have gotten a little paranoid about Rice email. TIA
--------------- Fagan Title+Abstract for ICCS 2006 Submission --------- Title: Derivatives by address for Fortran 77
Abstract:
Automatic differentiation tools use 1 of 2 strategies to access derivative values. These strategies are:
1) By-address 2) By-name
The by-address method is typically implemented by introducing structured types for each active scalar type. For example, scalar type 'real' will have an associated structure type 'active-real'. Using this strategy, all active variables types are changed to the associated structured type.
On the other hand, the by-name method introduces an associated new variable for each active variable. For example, the derivatives associated with 'pressure' would be 'd_pressure'.
Since the by-address strategy employs structured types, AD tools for Fortran 77 have not employed that strategy. In this paper, we show how to use array access to implement the by-address strategy for Fortran 77. We discuss the canonicalization issues, outline our Adifor3.0 implementation of this technique, and give a few sample performance comparisons of the by-address vs the standard Adifor3.0 by-name.