For Odyssée (see publications),
a *program* is a set of Fortran-77 units
(functions or subroutines), whose call-graph forms a tree. The root of
the tree is called the *head-unit*.
It is able to ``differentiate a program'', with
respect to the *input* variables (arguments and/or common variables) of
the head-unit.
The result of the differentiation of a program from its *head-unit* with respect to a set of active inputs is a new program,
which can compute at arbitrary points the derivative of the function
evaluated in the original program.

Odyssée can differentiate a program as a whole, detecting *active
variables*, those
whose value depends on the variables with respect to which the function is
differentiated.
Both the direct and reverse modes of differentiation are implemented.
The first one is appropriate for computing directional derivatives, the second
is adapted to the efficient computation of gradients.

Odyssée generates :

In Direct Mode, the tangent linear application which is the Jacobian
matrix times a vector.

In Reverse Mode, the cotangent linear application which is the
transposed Jacobian matrix times a vector in the dual space.

© `Copyright Notice`

1997 University of Nice Sophia Antipolis 1997 Institut National de Recherche en Informatique et en Automatique

**The source code of Odyssée is distributed**
`ftp://ftp-sop.inria.fr/tropics/odyssee`

If you have got any problem installing or using Odyssée, you acn contact Odyssée team at odyssee@sophia.inria.fr.

Present works on Odyssée are performed within different kinds of collaborations :

- DECISION
(HPCN) :
An european project in Integrated Optimization Strategies for
Increased Engineering Design Complexity.
- MIO (french
text) :
Cooperative research action supported by INRIA.
- GENIE
program :
Association of Dassault-Aviation, Aérospatiale and INRIA
partially supported by the ministry in charge of research.
- Research and development contract partially supported by
EDF-DER.
- Consultancy contract performed by Simulog.

It is used at various places by academics or industries.

Here is a list of some new tools : FADBAD and TADIFF, HSL, ADMAT (ADMIT), MIPAD.

Christele Faure , last update on May 1999