Serge Torres
LIP - Éns de Lyon
46, allée d'Italie
F-69364 Lyon Cedex 07
Phone: +33 (0) 4 72 72 86 48 or +33 (0) 04 37 28 76 45

Welcome to my scanty Home Page!
Hi! I'm a research engineer with the LIP laboratory at Éns de Lyon. I share my worktime between the laboratory IT management team (MI-LIP) and the AriC research team.

My main research topic is function approximation by polynomials and rational fractions. More precisely, I apply linear programming tools (exact and/or parametric linear programming) to the search of optimal “constrained” (e. g. bit size and/or pattern) polynomial coefficients. Initially this work has been performed in support of scientists and Ph.D. students1 of the team. For the last years it has become a more personnal project in the preparation of my own Ph.D. thesis under the supervision of Nicolas Brisebarre and Jean-Michel Muller.

My favorite gears for this kind of work are still PIP and GLPK. ISL and SCIP are promizing alternatives. I also extensively use Sollya, as mostly everyone in the team. MPFR is an undispensable tool of the trade to all high-precision numerics craftsmen. SAGE is the current game in town as for mathematical software system, at least for those who want to stand on the free side.

In the context of the development of an implémentation of the SLZ2 algorithm in Sage, I am developping interfaces between Sage and C, on the one hand, and Sollya, on the other hand. This work-in-progress is openly available from svn checkout

PERL, Bash and Python are also put to use for gluing tools together.

Some of the code I've put up together can be found under the MEPLIB project (badly out of sync too!).

For IT management duties, my MI-LIP buddies are Simon Delamare, Jean-Christophe Mignot, and Dominique Ponsard and we run a mostly Debian shop here.

1Sylvain Chevillard, Mioara Joldeş, Christoph Lauter.

2 See: D.  Stehlé, V.  Lefèvre, P.  Zimmerman. Worst Cases abd Lattice Reduction, in: Proceedings of the 16th IEEE Symposium on Computer Arithmetic, 2003, Santiago de Compostela, Spain, pp.142–147.


End 2015
Ph.D. defense on sight.


F. de Dinechin, C. Lauter, J.-M. Muller, S.Torres.
On Ziv's Rounding Test.,
in: ACM Transactions on Mathematical Software, Vol. 39(4), 2013.

J.-M. Muller, N. Brisebarre, F. de Dinechin, C.-P. Jeannerod, V. Lefèvre, G. Melquiond N. Revol, D. Stehlé, S.Torres.
Handbook of Floating-Point Arithmetic.,
Birkhäuser Boston, 2010.

N. Brisebarre, S. Chevillard, M. Ercegovac, J.-M. Muller, S. Torres.
An efficient Method for Evaluating Polynomial and Rational Function Approximations,
in: Application-specific Systems, Architectures and Processors, IEEE, 2008, p. 245–250.

N. Brisebarre, J.-M. Muller, A. Tisserand, S. Torres.
Hardware Operators for Function Evaluation Using Sparse-Coefficient Polynomials,
in: Electronic Letters, Vol. 42, Issue: 25, 2006, p. 1441–1442.