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Christoph Quirin Lauter
Associate Professor at University of Texas at El Paso (UTEP).
Maître de conférences habilité en disponiblité in the PEQUAN project at the LIP6 lab of Sorbonne University.
Before that Assistant and Associate Professor (Tenured) at University of Alaska Anchorage (UAA) (2018-2022).
Before that and meanwhile, Software Engineer for Intel Corporation, member of the Numerics team (2008-2010 and January through July 2022).
Former Ph.D. student under
Florent de Dinechin, in the Arénaire project, at
LIP.
Married, one little daughter, one little son.
Research interests:
The subject of my Ph.D. thesis has been the correct rounding of
elementary functions, such as exp(x), log(x), sin(x), asin(x), power(x,y),
in IEEE 754 double precision.
The implementation of elementary functions faces several difficulties of different kind:
I participated on the revision of the IEEE 754 standard that reigns
floating-point arithmetic. With Florent de Dinechin and
Jean-Michel Muller, I proposed the following
reformulation of the chapter on
elementary functions. The proposal can be found
here. A second remark on the draft version 1.6.0 of january 10, 2008 can be
found here.
I have done research on how the implementation and certification of
a mathematical function can be automatized. Starting from this, I have been interested
on safe algorithms for some high-level computation problems. As an example,
let me mention the computation of the infinity norm
of a composite function. Here, computation means giving an under- and, more important, an over-estimate of the
unknown supremum of the function. The function itself is given as an expression tree. Its leaves are basic functions or
"black-box" codes. Of course, the multi-precision evaluation of such a tree in a point or small interval is an important sub-problem.
This yields directly to questions on how intermediate precision must be adapted for ensuring a faithful rounding...
I have integrated those algorithms in the software tool Sollya. Sollya is intended as a safe support for the development of elementary functions. I used then Sollya for my Metalibm project, striving to an automatic implementer for mathematical (libm) functions.
In the recent years, for my research published e.g. with
my Habilitation à
Diriger des Recherches, I investigated means to implement and,
in particular, extend the typical IEEE754 floating-point environment
with respect to several dimensions, such as:
- implementation of the IEEE754 heterogeneous operations without special hardware by reusing Ziv's rounding test,
- providing implementations for correctly rounded IEEE754 decimal-character-to-binary-floating-point conversions with O(1) bounded memory consumption and O(n) time complexity,
- providing proven implementations in both floating-point and integer arithmetic to implement the so-called IEEE754-2019 augmented operations,
- extending IEEE754 by providing exact, i.e. error-free, comparisons between binary and decimal floating-point formats,
- extending IEEE754 by providing general-purpose mixed-radix arithmetical operations working on any combination of binary and decimal floating-point inputs and outputs,
- extending the floating-point environment with faithfully rounded higher-level operations, such as Euclidian norms, free of spurious overflow or underflow,
- extending the floating-point environment with code generation for mathematical functions, including functions for which no reference implementation is available,
- extending the floating-point environment with high-level, multi-precision operations with a priori error bounds, such as the WCPG measure for LTI filters.
Short curriculum vitae:
Ph.D. students and interns I work with or I used to work with:
Publications:
Articles in international journals:
- Arithmetic approaches for rigorous design of Fixed-Point LTI filters,
with Thibault Hilaire,
and Anastasiia Volkova, in IEEE Transactions on Computers, 2019.
- MPDI: A Decimal Multiple-Precision Interval Arithmetic Library,
with Stef Graillat and Clothilde Jeangoudoux, in Reliable Computing Journal, vol. 25, 2017.
- Comparison between binary and decimal floating-point
numbers,
with Nicolas
Brisebarre, Marc
Mezzarobba
and Jean-Michel
Muller, in IEEE Transactions on Computers, vol. 65, number 7, July 2016.
- Efficient calculations of faithfully rounded l2-norms of n-vectors,
with Stef Graillat, Ping Tak Peter Tang, Naoya Yamanaka
and Shin'ichi Oishi, in ACM Transactions on Mathematical Software, vol. 41, number 4, October 2015.
- On Ziv's rounding test,
with Florent de Dinechin,
Jean-Michel
Muller
and Serge
Torres, in ACM Transactions on Mathematical Software, vol. 39,
number 4, 2013; Preprint in research report ensl-00693317,
LIP, CNRS/ENS Lyon/INRIA/Université de Lyon, LIP6, PEQUAN, UPMC
Paris 6, May 2012.
- Efficient and accurate computation of upper bounds of approximation errors,
with Sylvain Chevillard,
John Harrison and Mioara
Joldeş, in Theoretical Computer Science, vol. 412, issue 16, pages 1523-1543, 2011, Final version; Preprint
in research report 2010-2, LIP, École Normale Supérieure de
Lyon, July 2010.
- Certifying the floating-point implementation of an
elementary function using Gappa,
with Florent
de Dinechin
and Guillaume
Melquiond, in IEEE Transactions on Computers, vol. 60, number 2, pages 242-253, 2011, Final version; Preprint
in research report INRIA inria-00533968, November 2010.
- Computing Correctly Rounded Integer Powers in Floating-Point Arithmetic,
with Jean-Michel Muller,
Peter Kornerup,
Vincent Lefèvre and
Nicolas
Louvet, in ACM Transactions on Mathematical Software, Vol. 37,
No. 1, Article 4, January 2010,
Preprint
in research report 2008-15, LIP, École Normale Supérieure de
Lyon, May 2008.
- An efficient rounding boundary test for pow(x,y) in double
precision, with Vincent
Lefèvre, in IEEE Transactions on Computers, 2009, vol. 58, 2, pages 197-207, February 2009.
Preprint
in research report 2007-36, LIP, École Normale Supérieure de
Lyon, August 2007.
- Fast and correctly rounded logarithms in double-precision,
with Florent de Dinechin
and Jean-Michel Muller, in
RAIRO, Theoretical Informatics and Applications, 2007, vol. 41, pages 85-102,
Preprint
in research report 2005-37, LIP, École Normale Supérieure de
Lyon, September 2005.
Articles in the proceedings of international conferences:
- A Framework for Semi-Automatic Precision and Accuracy Analysis for Fast and Rigorous Deep Learning,
with Anastasiia Volkova, in Proceedings of the 27th IEEE Symposium on
Computer Arithmetic, Online due to Covid-19, USA.
- Precision Adaptation for Fast and Accurate Polynomial Evaluation Generation,
with Nicolas Brunie and Guillaume Revy, in Proceedings of the 2019 IEEE 30th International Conference on Application-specific Systems, New York, NY, USA.
- Rigorous Polynomial Approximation,
in Proceedings of
the 2018 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2018.
- A correctly rounded mixed-radix fused-multiply-add,
with Clothilde Jeangoudoux, in Proceedings of the 2018 IEEE 25th SYMPOSIUM on Computer Arithmetic, Amherst, MA, USA, July 2018.
- Why Taylor models and modified Taylor models are empirically successful: a symmetry-based explanation,
with Mioara
Joldeş, Martine Ceberio, Olga Kosheleva and Vladik Kreinovich, in Proceedings of the 8th International Workshop on Reliable Engineering Computing REC'2018, July 2018.
- A parallel compensated Horner scheme,
with Stef Graillat, Youness Ibrahimy and Clothilde Jeangoudoux, in Proceedings of CSE 2017, SIAM Conference on Computational Science and Engineering (CSE), 2017.
- An efficient software implementation of correctly rounded operations extending FMA: a + b + c and a * b + c * d,
in Proceedings of
the 2017 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2017.
- Rigorous determination of recursive filter fixed-point implementation with input signal frequency specifications,
with Anastasiia Volkova, Thibault Hilaire and Marc Mezzarobba,
in Proceedings of
the 2017 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2017.
- Reliable verification of digital implemented filters against frequency specifications,
with Anastasiia Volkova and Thibault Hilaire,
in Proceedings of
the 2017 IEEE 24th SYMPOSIUM on Computer Arithmetic, London, UK, July 2017.
- A new Open-Source SIMD Vector Libm Fully Implemented With High Level Scalar C,
in Proceedings of
the 2016 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2016.
- MPDI: A Decimal Multiple-Precision Interval Arithmetic Library,
with Stef Graillat and Clothilde Jeangoudoux, in Proceedings of SCAN 2016, Uppsala, Sweden, 2016.
- Easing Development of Precision-Sensitive Applications with a Beyond-Quad-Precision Library,
in Proceedings of
the 2015 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2015.
- Determining Fixed-Point Formats for a Digital Filter Implementation using the Worst-Case Peak Gain Measure,
with Anastasiia Volkova and Thibault Hilaire,
in Proceedings of
the 2015 Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, USA, 2015.
- Code generators for mathematical functions,
with Nicolas Brunie, Florent de Dinechin and Olga Kupriianova, in Proceedings of the 22nd IEEE Symposium on
Computer Arithmetic, pages 66-73, Lyon, France,
2015, Best Paper Award.
- Reliable evaluation of the worst-case peak gain matrix in
multiple precision,
with Thibault Hilaire
and Anastasiia Volkova,
in Proceedings of
the 22nd IEEE Symposium
on Computer Arithmetic, Lyon, France, 2015.
- Semi-Automatic Floating-Point Implementation of Special Functions,
with Marc Mezzarobba,
in Proceedings of
the 22nd IEEE Symposium
on Computer Arithmetic, Lyon, France, 2015.
- A Domain Splitting Algorithm for the Mathematical Functions Code Generator,
with Olga Kupriianova,
in Proceedings of
the 2014 Asilomar Conference on Signals, Systems and Computers, pages 1271-1275, Pacific Grove, CA, USA, 2014.
- Metalibm: Mathematical Functions Code Generator,
with Olga Kupriianova,
in Proceedings of
the 4th International Congress on Mathematical Software ICMS, pages 713-717, Seoul, South Korea, 2014.
- Radix Conversion for IEEE754-2008 Mixed Radix Floating-Point Arithmetic,
with Olga Kupriianova and Jean-Michel
Muller,
in Proceedings of
the 2013 Asilomar Conference on Signals, Systems and Computers, pages 1139-1143, Pacific Grove, CA, USA, 2013.
- Comparison between binary64 and decimal64 floating-point numbers,
with Nicolas Brisebarre, Marc Mezzarobba and Jean-Michel
Muller, in Proceedings of the 21st IEEE Symposium on
Computer Arithmetic, pages 145-152, Austin, Texas, USA,
April
2013, Preprint
in research report ARIC, LIP, PEQUAN, LIP6, Number ensl-00737881, Slides.
- Sollya: an environment for the development of numerical codes,
with Sylvain
Chevillard
and Mioara
Joldeş, in Proceedings of the Third international congress conference on Mathematical Software, ICMS'10, pages 28-31, Kobe, Japan,
September 2010, LNCS, Springer, Final version.
- Certified and fast computation of supremum norms of
approximation errors,
with Sylvain
Chevillard
and Mioara
Joldeş, in Proceedings of the 19th IEEE Symposium on
Computer Arithmetic, pages 169-176, Portland, Oregon, USA,
July
2009, Preprint
in research report 2008-37, LIP, École Normale Supérieure de
Lyon, October 2008.
- Optimizing polynomials for floating-point implementation,
with Florent de Dinechin, in
Proceedings of the 8th Conference on Real Numbers and
Computers, pages 7-16, Santiago de Compostela, Spain, July
2008, Preprint
in research report 2008-11, LIP, École Normale Supérieure de
Lyon, March 2008.
- A certified infinite norm for the implementation of elementary functions,
with Sylvain Chevillard, in
Proceedings of the
Seventh International
Conference on Quality Software, pages 153-160, Portland,
Oregon, USA, October 2007,
Preprint and
Extended Version in research report
2007-26, LIP, École Normale Supérieure de Lyon, June 2007.
- Assisted verification of elementary functions using Gappa,
with Florent de Dinechin
and Guillaume Melquiond, in
Proceedings of the 21st Annual ACM Symposium on Applied
Computing - MCMS Track, vol. 2, pages 1318-1322, Dijon,
France, April 2006,
Preprint and
Extended Version in research report #5683, INRIA, September 2005.
Research reports:
- On Ziv's rounding test,
with Florent de Dinechin,
Jean-Michel
Muller
and Serge
Torres, Research report ensl-00693317,
LIP, CNRS/ENS Lyon/INRIA/Université de Lyon, LIP6, PEQUAN, UPMC
Paris 6, May 2012.
- Efficient and accurate computation of upper bounds of approximation errors,
with Sylvain
Chevillard,
John Harrison
and Mioara
Joldeş, Research report
2010-2, LIP, CNRS/ENS Lyon/INRIA/Université de Lyon, INRIA, LORIA, CACAO project and
Intel Corporation, Hillsboro,
Oregon, USA, January 2010. Article submitted to Theoretical
Computer Science; Special Issue on Symbolic and Numeric
Computation, 2009.
- Certifying floating-point implementations using Gappa,
with Florent de Dinechin
and Guillaume Melquiond,
Research report
arXiv: 0801.0523, LIP, CNRS/ENS Lyon/INRIA/Université de Lyon,
January 2008.
- Exact and mid-point rounding cases of power(x,y),
Research report
2006-46, LIP, École Normale Supérieure de Lyon, December 2006.
- Basic building blocks for a triple-double intermediate format,
Research report
RR-5702, INRIA, September 2005.
- Fast correct rounding of elementary functions in double
precision using double-extended arithmetic,
with Florent
de Dinechin
and David Defour,
Research report
2004-10, LIP, École Normale Supérieure de Lyon, March 2004.
- A correctly rounded implementation of the exponential
function on the Intel Itanium architecture,
Research report
RR-5024, INRIA, December 2003.
Master's, Ph.D. thesis, Habilitation (HDR) thesis:
- Beyond IEEE754 Floating-Point Arithmetic,
Habilitation à Diriger des Recherches (HDR),
Sorbonne Université, May 2019.
- Arrondi correct de fonctions mathématiques - Fonctions
univariées et bivariées, certification et automatisation,
Thèse de doctorat,
École Normale Supérieure de Lyon, October 2008.
- Effective evaluation of correctly rounded elementary
functions using triple-double intermediate representation,
Master's thesis, Technische Universität München, Faculty of Computer Science, September 2005.
- Ressourcenmanagement über drahtgebundene und drahtlose
LAN, Thesis for a development project, Technische Universität München, Chair for Communication Networks, 2004.
Presentations and Workshops:
- Conception d’un algorithme numérique correct, with Guillaume
Melquiond, CNRS Thematic School: Précision et Reproductibilité en Calcul Numérique, Fréjus, France, March 2013, Slides.
- The libieee754 compliance library for the IEEE 754-2008 standard,
with Olga Kupriianova,
15th GAMM - IMACS International Symposion on Scientific Computing, Computer Arithmetic and Validated Numerics, Novosibirsk, Russia, September 2012.
- There's no Reliable Computing without Reliable Access to Rounding Modes,
with Valérie Ménissier-Morain,
15th GAMM - IMACS International Symposion on Scientific Computing, Computer Arithmetic and Validated Numerics, Novosibirsk, Russia, September 2012.
- De l'implantation de fonctions correctement arrondies aux bibliothèques LIBM IEEE 754-2008 clef en main,
Presentation for the workshop of the PEQUAN team,
Paris, France, February 2011, Slides.
- L'implantation d'une fonction correctement arrondie, ou : CRLibm for dummies,
Presentation for the ANR TaMaDi project,
Lyon, France, October 2010, Slides.
- Sollya - a numerical software tool for the semi-automatic
implementation of efficient correctly rounded mathematical
functions, presentation on invitation for the conference ACA
2008, Hagenberg, Austria, July
2008, Abstract.
- Quand les boucles deviennent des polynômes ou l'implantation automatique de fonctions,
Presentation at the RAIM 2008 days,
Lille, France, June 2008, Slides.
- Vers une implémentation automatique de fonctions libm,
Presentation for the EVA-Flo project,
Perpignan, France, October 2007, Slides.
- Advancements in (cr)libm development,
Presentation for Intel Portland,
Portland, Orgeon, USA, October 2007, Slides.
- Towards automatic generation of elementary functions,
Presentation for the russian team in the Intel Numerics Group,
Nizhny Novgorod, Russia, August 2007, Slides.
- Automatisation du contrôle de précision et de la preuve pour les formats double-double et triple-double,
Workshop of the CACAO project, LORIA, Nancy, France, January 2007.
- A Survey of Multiple-Precision Using Floating-Point Arithmetic,
Fourth International Workshop on Taylor Methods, Boca Raton, Florida, USA, December 2006,
Abstract, Slides.
- Certified infinite norm using interval arithmetic,
with Sylvain Chevillard,
12th GAMM - IMACS International Symposion on Scientific Computing, Computer Arithmetic and Validated Numerics, Duisburg, Germany, September 2006, Abstract.
- Normes infinies certifiées par l'arithmétique d'intervalles,
Journées Nationales d'Arithmétique des Ordinateurs 2006, May-June 2006,
Slides.
- Correctly rounding elementary functions using triple-double intermediate representation,
Journées Arinews, Perpignan, France, November 2005,
Slides.
Miscellaneous:
- Users' manual for the Sollya tool, Release 7.0,
with Sylvain
Chevillard and Mioara
Joldeş, Users' manual.
- Users' manual for the Sollya tool, Release 6.0,
with Sylvain
Chevillard and Mioara
Joldeş, Users' manual.
- Users' manual for the Sollya tool, Release 5.0,
with Sylvain
Chevillard and Mioara
Joldeş, Users' manual.
- Users' manual for the Sollya tool, Release 4.0,
with Sylvain
Chevillard and Mioara
Joldeş, Users' manual.
- Users' manual for the Sollya tool, Release 3.0,
with Sylvain
Chevillard and Mioara
Joldeş, Users' manual.
Developed open source software:
Teaching:
- exercises in Parallel Numerics, Master Computer Science in Engineering, Technische Universität München
- exercises in Compiler Design, Master course, ENS Lyon
- exercises in Term Rewriting, Bachelor course, ENS Lyon
- exercises in Algorithms for Arithmetic 2007, Master course, ENS Lyon
- exercises in Architecture, Systems, Networks, Bachelor course, ENS Lyon
- exercises in Arithmetic 2008, Master course, ENS Lyon
- exercises in Initiation to task automatization (LI218), Bachelor course L2, UPMC Paris 6
- exercises in Introduction to imperative programming in C (LI115), Bachelor course L1, UPMC Paris 6
- exercise-projet in "Operational research and optimization", Master course M2, UPMC Paris 6
- exercises in Parallelism, course ELI4, École Polytech UPMC, Paris 6
- lectures and exercises in Introduction to imperative programming in C (LI115), Bachelor course L1, UPMC Paris 6
- exercises in Scientific Computing (LI217), Bachelor course L2, UPMC Paris 6
- lectures and exercises in Computer Arithmetic (AROR), Master Course, UPMC Paris 6
- lectures and exercises in Numerical representations and methods (2I011)", Bachelor course L2, UPMC Paris 6
- lectures and exercises in Error Analysis and Floating-Point Arithmetic (AFAE), Master Course, UPMC Paris 6
- lectures and exercises in Numerical representations and methods (2I011)", Bachelor course L2, UPMC Paris 6
- courses in Operating Systems - CSCE A321, Bachelor, University of Alaska Anchorage
- courses in Automata, Algorithms and Complexity - CSCE A351, Bachelor, University of Alaska Anchorage
- courses in Computer Programming I (Java) - CSCE A201, Bachelor, University of Alaska Anchorage
Contact:
Phone Collection:
As a hobby, I collect old telephone sets and the technology that goes with that. Some information can be found on this page.
Last update: 02/05/2024.
