-------- 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. -- Prof. Christian Bischof, Ph.D. Institute for Scientific Computing and Center for Computing and Communications RWTH Aachen University Seffenter Weg 23, 52074 Aachen, Germany Tel. +49-241-8029110, Fax +49-241-8022241 bischof@rz.rwth-aachen.de <mailto:bischof@rz.rwth-aachen.de>, www.sc.rwth-aachen.de <http://www.sc.rwth-aachen.de/>, www.rz.rwth-aachen.de <http://www.rz.rwth-aachen.de/>