Annual Report 2010 - Fachgruppe Informatik an der RWTH Aachen ...

Research Projects
AC-SAMMM
U. Naumann, B. Gendler, M. Förster
Collaborators: Prof. Dr. W. Marquardt, AVT Aachener Verfahrenstechnik Prof. Marquardt,
Funded by: ERS boost fund
The development of AaChen Platform for Structured Automatic Manipulation of
Mathematical Models (AC-SAMMM) started in October 2009.
The industrial processes are described in mathematical models consisting of algebraic
equations, formulated in some high-level modeling language (e.g. gPROMS). The derivatives
of these models are highly desirable by the industry.
The first step in the chain of AC-SAMMM is the translation of the algebraic equations into
C++. This work is done by AVT. To generate first order derivative code for a given C++
implementation of a numeric function Derivative Code Compiler (DCC) is used. DCC is
developed by STCE. It is possible to reapply DCC on its own output to get the derivatives of
higher orders. We applied AC-SAMMM on a real-life pharmacological problem, with over
2000 algebraic equations. The resulting C++ code consists of 9.000 lines. Applying DCC to
this code yields a derivative code with 44.000 lines. The second order derivative code,
generated by DCC, has 180.000 lines.
To simplify the usage of AC-SAMMM we currently develop a library allowing the
computation of the first and second derivatives in an automatic way, exploiting the sparsity
structure of the Jacobian and Hessian. The user has only to specify a function and a desired
order of differentiation.
JURASSIC
E. Varnik, M. Förster, U. Naumann, J. Lotz
Collaborators: ICG-1, Forschungszentrum Jülich
Funded by: DFG
The JUelich RApid Spectral SImulation Code is a radiative transfer model for the infrared
spectral region developed at the Institute for Chemistry and Dynamics of the Geosphere
(ICG-1) at the Forschungszentrum Jülich. The main focus of our collaboration is a part of the
JURASSIC package called retrieval processor, which tries to estimate the retrieval parameters
by minimizing the cost function representing the deviations between real and simulated
observations for a given state as well as the differences between the estimated state and an a
priori state. Our main investigations so far have been focused on enabling JURASSIC to
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