Parisian Master of Research in Computer Science
Master Parisien de Recherche en Informatique (MPRI)

Efficient Algorithms in Computer Algebra (48h, 6 ECTS)

French title: Algorithmes efficaces en calcul formel.

In charge: Vincent Neiger

Objectives

Computer Algebra (also known as Symbolic Computation, or Calcul formel in French) consists in developing computer representations and manipulations of mathematical objects in an exact way, in contrast with traditional scientific computing, for example. As a counterpart of such exact algebraic representations, computation times are often large and memory requirements are often huge if one employs naive algorithms. In this course, we introduce basic computer-algebra algorithms to work with polynomials, series, and matrices, so as to achieve in many cases quasi-optimal complexity bounds. Such algorithms are largely used in practice in computer-algebra systems, but as well in several other modern algorithmic domains that rely on algebraic techniques, such as cryptography, multivariate cryptoanalysis, and error-correcting codes.

In a second part of the course, we enter more specialized, active research domains, including symbolic summation and integration. The symbolic summation and integration methods that we describe have become unexpendable computation tools for physics, the numeric evaluation of special functions, the modelling of combinatorial problems, and more broadly for difficult questions of formulas simplification.

This course is particularly well suited to those who wish to rigorously understand the algorithmic foundations of algebraic calculation and their general principles, as a supplement of the courses Systèmes polynomiaux, calcul formel et applications (Polynomial Systems, computer algebra, and applications 2-13-1), Codes correcteurs d'erreurs et applications à la cryptographie (Error correcting codes and applications to cryptography 2-13-2), Techniques en cryptographie et cryptanalyse (Techniques in cryptography and cryptanalysis 2-12-1), Algorithmes arithmétiques pour la cryptologie (Arithmetic algorithms for cryptology 2-12-2) and Analyse d'algorithmes (Analysis of algorithms 2-15).

Organization for 2022-2023

This webpage holds the contents of the whole course and will be updated on a weekly basis to integrate various notes and documents, and potentially to reflect evolutions based on what could be presented during lectures.

Time and location for 2022-2023

On Tuesdays, 12:45-15:45, room 1004.

Professors
Language

Summary: English spoken if requested, otherwise French spoken; all slides in English; book in French.

In line with the MPRI terminology, the course is a module “English upon request”, meaning that (oral) lectures will be in French, unless at least one non-French-speaking student requests English (from 2020 until now, the course has been fully taught in English). Nevertheless, our main reference book was written in French and will not be translated. In all lectures, whatever the spoken language, slides will be written in English. In all cases, students will be allowed to take their exams in French or English.

Periods and evaluation

Except for students who will officially chose to quit the course after the first half (“breakable module”), the global mark will be an average between the marks for the first and second halves of the course. Documents allowed during examinations will be the book and personal notes by the student.

The course is breakable, so that students may elect not to attend the second period (thus validating only half of the ECTS). We strongly recommend against attending the second period only.

Book: AECF

Other useful references can be found at the end of this wepage.

Lecture 1. 20/09

Vincent Neiger

General presentation of the course. Fast polynomial multiplication. (Chapters 1 and 2) Documents

Lecture 2. 27/09

Alin Bostan

Dense linear algebra: from Gauss to Strassen. (Chapter 8) Slides

Lecture 3. 04/10

Alin Bostan

Fast evaluation and interpolation. Gcd. (Chapters 5 and 6)

Lecture 4. 11/10

Alin Bostan

Resultant. Fast computations with series. (Chapters 3 and 6)

Lecture 5. 18/10

Alin Bostan

D-finite power series. (Chapter 4)

Lecture 6. 25/10

Alin Bostan

Linear recurrences: constant coefficients and rational functions, polynomial coefficients: n-th term, first n terms. (Chapters 4 and 15)

ATTENTION: NO LECTURE ON 01/11!

Lecture 7. 08/11

Vincent Neiger

Computations with polynomial matrices: introduction and motivations.

Lecture 8. 15/11

Alin Bostan

Exercises session.

ATTENTION: NO LECTURE ON 22/11!

FIRST-PERIOD EXAM ON 29/11

Some rules: The consultation of static data (lessons and personal notes) on an electronic device is authorized, provided that these devices are not connected to any network. Consultation of the course and personal notes on paper is authorized.

Lecture 9. 06/12

Vincent Neiger

Polynomial matrices: fast Hermite-Padé approximation and vector interpolation.

Lecture 10. 13/12

Vincent Neiger

Using polynomial matrices for sparse linear algebra, structured system solving, and bivariate interpolation

Lecture 11. 03/01

Pierre Lairez

Polynomial factorization over finite fields. (Chap 19)

ATTENTION: NO LECTURE ON 10/01!

Lecture 12. 17/01

Pierre Lairez

Factorization over the integers, lattice reduction. (Chapters 20 and 21)

Lecture 13. 24/01

Pierre Lairez

Integration I.

Lecture 14. 31/01

Pierre Lairez

Integration II.

Lecture 15. 07/02

Alin Bostan

Computer algebra for combinatorics.

Lecture 16. 14/02

Alin Bostan

Exercises session.

ATTENTION: NO LECTURE ON 21/02!

SECOND-PERIOD EXAM ON 28/02

Bibliography

General works:

  • D. Cox, J. Little, D. O'Shea, Ideals, Varieties and Algorithms. Undergraduate Texts in Mathematics, Springer Verlag, 2nd edition, 1996.
  • J. von zur Gathen, J. Gerhard, Modern Computer Algebra, Cambridge University Press, 1999.
  • M. Petkovsek, W. Wilf, D. Zeilberger, A=B, A. K. Peters, 1996.
  • K. O. Geddes, S. R. Czapor, G. Labahn, Algorithms for Computer Algebra, Kluwer Academic Publishers, 1992.

The book emanating from our lectures over the past years:

  • A. Bostan, F. Chyzak, M. Giusti, R. Lebreton, G. Lecerf, B. Salvy and É. Schost, Algorithmes Efficaces en Calcul Formel. Printed by CreateSpace. Palaiseau: F. Chyzak (self-ed.), 2017. Also available for free in electronic format. https://hal.archives-ouvertes.fr/AECF/.

Pedagogical team

Alin BostanDRInria Saclay ÎDF
Frédéric ChyzakDRInria Saclay ÎDF
Pierre LairezCRInria Saclay ÎDF
Vincent NeigerMdCSorbonne Université
 
Universités partenaires Université Paris-Diderot
Université Paris-Saclay
ENS Cachan École polytechnique Télécom ParisTech
ENS
Établissements associés Université Pierre-et-Marie-Curie CNRS INRIA CEA