Mioara Joldes

7 Avenue du Colonel Roche,
31077 Toulouse, Cedex 4 France

phone:(+33) (0)5 61 33 69 26
email: joldes AT laas DOT fr

CV, Publications and Software, Talks, Miscelaneous.

Researcher (Chargé de Recherche) at CNRS in the ROC team, at LAAS.

Research Themes and Objectives

bookRigorous computing (validated computing): use numerical computations, but provide mathematical statements about the obtained result, such as sure, yet reasonably tight, error bounds. Build efficient symbolic-numeric objects, algorithms and software tools with direct applications in control of dynamical systems and in particular in the aerospace domain. Use and develop expertise and ideas from Computer Arithmetic and Computer Algebra. See for instance my Habiliation (HDR) defended June 2019 or the HDR Slides.

A. Computer Arithmetic:

With Valentina Popescu and Jean-Michel Muller, we developed algorithms for fast and certified multiple precision arithmetic operations (also tuned for Graphics Processing Units). We targeted high-performance computing problems which require multiple precision e.g., the study of strange attractors such as the Hénon attractor [6]. Valentina defended her PhD thesis, co-supervised with Jean-Michel Muller, on 6th of July 2017. Some related articles are [6][3][13][14][19]. Other goals: formally proven algorithms, elementary functions implementation. Some talks: [ASAP14] [Henon13][SMC14][ICMS16]

This work is also presented in the 2nd edition of Handbook of Floating-Point Arithmetic, coordinated by Jean-Michel Muller, published by Birkhäuser (2018)

With Denis Arzelier and Florent Bréhard, we presented at Arith (2019) an exchange algorithm for evaluation and approximation error-optimized polynomials  [9].

B. Rigorous Polynomial Approximation (RPA): a polynomial approximation together with rigorous error bounds. Use Taylor Models [7252620] and Chebyshev polynomial interpolation/series Models [22][30, Chap. 4]. Adapt to rigorous computations many numerical algorithms based on Chebyshev/Taylor Series for solving ordinary differential equations, quadrature, etc. Recent results: compute rigorous uniform approximations based on Chebyshev Series for D-finite functions, i.e. solutions of ordinary differential equations with polynomial coefficients [3] e.g., erf, exp, sin, Bessel, Airy functions.

With Florent Bréhard and Nicolas Brisebarre, we developed a validated numerics method for the solution of linear ordinary differential equations (LODEs). A theoretical and practical complexity analysis of a so-called a posteriori quasi-Newton validation method is given in [1].

Objectives: efficient implementation of operations with Chebyshev Models, extensions to multivariate functions; efficient finite precision evaluation of power series. Some talks: [RPA] [TAMADI][SeaMac][RAIM2017]

C. Applications to Optimal Control and Aerospace:

  • We proposed a new accurate, reliable and efficient method to compute a certified orbital collision probability between two spherical space objects involved in a short-term encounter under Gaussian-distributed uncertainty. In this model of conjunction, the probability of collision is reduced to the integral of a 2D Gaussian probability density function over a disk. Our computational method is based on an analytic expression for the integral, derived by use of Laplace transform and D-finite functions [17184]. This work is to be extended to long term or multiple encounters during the R&T CNES project Global Collision Probability and Satellites Station Keeping (started 09/16). Talks: [JNCF] [CAPA] [CMS16]

With Denis Arzelier, Florent Bréhard, and Jean-Bernard Lasserre, we are currently attempting to approximately reconstruct the support of the initial collision-prone states in a two-objects long-term encounter. A preliminary result at ISSAC2019 has received the Distinguished Paper Award [10]. Given a finite number of numerically computed moments for a measure with holonomic density, and assuming a real algebraic boundary for the support, we develop a method for obtaining the coefficients of a polynomial vanishing on this boundary.

  • A new numerical convergent algorithm based on semi-infinite convex optimization for linearized impulsive fixed-time fuel-optimal space rendezvous. Its solution is then used in a general simple procedure dedicated to the computation of the optimal velocity increments and optimal impulses locations. It is also shown that the semi-infinite convex programming has an analytical solution obtained via a simple geometrical construction for the out-of-plane rendezvous problem.[813] Talks: [Fastrelax16]
  • With Paulo Arantes Gilz, Christophe Louembet et Frédéric Camps, we proposed a model predictive control strategy for the hovering phases of the impulsive spacecraft rendezvous. The path constraints (box-type and periodicity) are satisfied continuously in time, based on a particular parametrization of the linearized relative spacecraft trajectories. Hardware-in-the-loop simulations, using a synthesized LEON3 microprocessor which is compatible with space devices, are performed to assess the efficiency and robustness of the proposed approach[9] [12][31]. Paulo defended his PhD Thesis, co-supervised with Christophe Louembet, on 17 October 2018.

Recent Software:




    Handbook of Floating-Point Arithmetic, coordinated by Jean-Michel Muller, published by Birkhäuser (2018).

International peer-reviewed journals

[1]   Paulo Ricardo Arantes Gilz, Mioara Joldes, Christophe Louembet and Frédéric Camps. Stable Model Predictive Strategy for Rendezvous Hovering Phases Allowing for Control Saturation Journal of Guidance, Control, and Dynamics. To Appear 2019 Preliminary version.

[2]   Florent Bréhard, Nicolas Brisebarre, and Mioara Joldes. Validated and numerically efficient Chebyshev spectral methods for linear ordinary differential equations. ACM Trans. Math. Software 44, 4, Article 44 (July 2018), 42 p. Preliminary version.

[3]   Mioara Joldes, Jean-Michel Muller, and Valentina Popescu. Tight and rigourous error bounds for basic building blocks of double-word arithmetic. ACM Transactions on Math. Software 44.2 (2017):15. Preliminary version.

[4]   Alexandre Benoit, Mioara Joldes, and Marc Mezzarobba. Rigorous uniform approximation of d-finite functions using chebyshev expansions. Math. Comput., 86(305):1303–1341, 2017. Preliminary version.

[5]   Romain Serra, Denis Arzelier, Mioara Joldes, Jean-Bernard Lasserre, Aude Rondepierre, and Bruno Salvy. Fast and accurate computation of orbital collision probability for short-term encounters. Journal of Guidance, Control, and Dynamics, 39(5):1009–1021, 2016. Preliminary version.

[6]   Mioara Joldes, Olivier Marty, Jean-Michel Muller, and Valentina Popescu. Arithmetic algorithms for extended precision using floating-point expansions. IEEE Transactions on Computers, 65(4):1197–1210, Apr 2016. Preliminary version.

[7]   Mioara Joldes, Valentina Popescu, and Warwick Tucker. Searching for sinks for the Hénon map using a multipleprecision GPU arithmetic library. SIGARCH Comput. Archit. News, 42(4):63–68, December 2014.Preliminary version.

[8]   Sylvain Chevillard, John Harrison, Mioara Joldes, and Christoph Lauter. Efficient and accurate computation of upper bounds of approximation errors. Theoretical Comp. Science, 16(412):1523–1543, 2011.Preliminary version.

Publications in the peer-reviewed proceedings of international conferences

[9]   Denis Arzelier, Florent Bréhard, Mioara Joldes. Exchange algorithm for evaluation and approximation error-optimized polynomials. In Proceedings of the IEEE 26th Symposium on Computer Arithmetic (ARITH), Kyoto, June 2019. Preliminary version.

[10]   Florent Bréhard, Mioara Joldes, Jean-Bernard Lasserre. On moment problems with holonomic functions. In Proceedings of the Symbolic and Algebraic Computation, International Symposium, ISSAC, 2019, Beijing, China, July 15-18, 2019. Preliminary version.

[11]   Romain Serra, Denis Arzelier, Florent Bréhard, Mioara Joldes. Fuel-optimal impulsive fixed-time trajectories in the linearized circular restricted 3-body-problem. In IAC 2018 - 69th International Astronautical Congress; IAF Astrodynamics Symposium, Oct 2018, Bremen, Germany. pp.1-9, 2018, CSA/IAF Special issue IAF Astrodynamics Symposium (69TH international astronautical congress). Preliminary version.

[12]   Frédéric Camps, Paulo Ricardo Arantes Gilz, Mioara Joldes, Christophe Louembet. Embedding a SDP-based control algorithm for the orbital rendezvous hovering phases. In Proceedings of IEEE International Conference on Integrated Navigation Systems, Jun 2018, Saint Petersburg, Russia. 10.23919/ICINS.2018.8405931Preliminary version.

[13]   Mioara Joldes, Jean-Michel Muller, and Valentina Popescu. Implementation and performance evaluation of an extended precision floating-point arithmetic library for high-accuracy semidefinite programming. In Proceedings of IEEE Symposium on Computer Arithmetic (Arith24), London, United Kingdom, July 2017. Preliminary version.

[14]   Sylvie Boldo, Mioara Joldes, Jean-Michel Muller, and Valentina Popescu. Formal Verification of a Floating-Point Expansion Renormalization Algorithm. In Proceedings of ITP2017: 8th International Conference on Interactive Theorem Proving, Brasilia, Brasil, 2017. Preliminary version

[15]   Paulo Ricardo Arantes Gilz, Mioara Joldes, Christophe Louembet, and Frédéric Camps. Model predictive control for rendezvous hovering phases based on a novel description of constrained trajectories. In Proceedings of IFAC 2017: The 20th World Congress of the International Federation of Automatic Control, 9-14 July 2017, Toulouse, France, July 2017. Preliminary version

[16]   Denis Arzelier, Florent Bréhard, Norbert Deak, Mioara Joldes, Christophe Louembet, Aude Rondepierre, and Romain Serra. Linearized impulsive fixed-time fuel-optimal space rendezvous: A new numerical approach. In Proceedings of 20th IFAC Symposium on Automatic Control in Aerospace, 21-25 Aug, 2016, Sherbrooke, Canada. Preliminary version

[17]   Sylvain Collange, Mioara Joldes, Jean-Michel Muller, and Valentina Popescu. Parallel floating-point expansions for extended-precision GPU computations. In Proceedings of ASAP 2016: 27th IEEE International Conference on Application-specific Systems, Architectures and Processors, 6-8 July 2016, London, England. Preliminary version

[18]   Florent Bréhard, Nicolas Brisebarre, and Mioara Joldes. A New Efficient Algorithm for Computing Validated Chebyshev Approximations Solutions of Linear Differential Equations . In SCAN2016: 17th International Symposium on Scientific Computing,Computer Arithmetic and Verified Numerics, Uppsala, Sweden, Sept. 2016, pages 41–43, 2016.

[19]   Mioara Joldes, Jean-Michel Muller, Valentina Popescu, and Warwick Tucker. Campary: Cuda multiple precision arithmetic library and applications. In Gert-Martin Greuel, Thorsten Koch, Peter Paule, and Andrew Sommese, editors, Mathematical Software – ICMS 2016: 5th International Conference, Berlin, Germany, July 11-14, 2016, Proceedings, pages 232–240, Cham, 2016. Springer International Publishing. Preliminary version

[20]   Romain Serra, Denis Arzelier, Mioara Joldes, Jean-Bernard Lasserre, Aude Rondepierre, and Bruno Salvy. A new method to compute the probability of collision for short-term space encounters. In Astrodynamics Specialist Conference, pages 1–7, Aug 2014.

[21]   Romain Serra, Denis Arzelier, Mioara Joldes, and Aude Rondepierre. Probabilistic collision avoidance for long-term space encouters via risk selection. In 3rd CEAS European Aerospace Guidance, Navigation and Control (EuroGNC) Conference, pages –21, Dec 2014.

[22]   Mioara Joldes, Jean-Michel Muller, and Valentina Popescu. On the computation of the reciprocal of floating point expansions using an adapted Newton-Raphson iteration. In IEEE 25th International Conference on Application-Specific Systems, Architectures and Processors, ASAP 2014, Zurich, Switzerland, June 18-20, 2014, pages 63–67. IEEE, 2014. Preliminary version.

[23]   Nicolas Brisebarre, Mioara Joldes, Érik Martin-Dorel, Micaela Mayero, Jean-Michel Muller, Ioana Pasca, Laurence Rideau, and Laurent Théry. Rigorous polynomial approximation using Taylor Models in Coq. In Alwyn Goodloe and Suzette Person, editors, NASA Formal Methods - 4th International Symposium, NFM 2012, Norfolk, VA, USA, April 3-5, 2012. Proceedings, volume 7226 of Lecture Notes in Computer Science, pages 85–99. Springer, 2012. Preliminary version

[24]   Nicolas Brisebarre, Mioara Joldes, Peter Kornerup, Érik Martin-Dorel, and Jean-Michel Muller. Augmented precision square roots and 2-d norms, and discussion on correctly rounding sqrt(x^2+y^2). In Elisardo Antelo, David Hough, and Paolo Ienne, editors, 20th IEEE Symposium on Computer Arithmetic, ARITH 2011, Tübingen, Germany, 25-27 July 2011, pages 23–30. IEEE Computer Society, 2011. Preliminary version

[25]   Nicolas Brisebarre and Mioara Joldes. Chebyshev interpolation polynomial-based tools for rigorous computing. In Wolfram Koepf, editor, Symbolic and Algebraic Computation, International Symposium, ISSAC 2010, Munich, Germany, July 25-28, 2010, Proceedings, pages 147–154. ACM, 2010.Preliminary version.

[26]   Florent de Dinechin, Mioara Joldes, and Bogdan Pasca. Automatic generation of polynomial-based hardware architectures for function evaluation. In François Charot, Frank Hannig, Jürgen Teich, and Christophe Wolinski, editors, 21st IEEE International Conference on Application-specific Systems Architectures and Processors, ASAP 2010, Rennes, France, 7-9 July 2010, pages 216–222. IEEE, 2010. Preliminary version.

[27]   Florent de Dinechin, Mioara Joldes, Bogdan Pasca, and Guillaume Revy. Multiplicative square root algorithms for FPGAs. In International Conference on Field Programmable Logic and Applications, FPL 2010, August 31 2010 - September 2, 2010, Milano, Italy, pages 574–577. IEEE, 2010. Preliminary version

[28]   Sylvain Chevillard, Mioara Joldes, and Christoph Quirin Lauter. Sollya: An environment for the development of numerical codes. In Komei Fukuda, Joris van der Hoeven, Michael Joswig, and Nobuki Takayama, editors, Mathematical Software - ICMS 2010, Third International Congress on Mathematical Software, Kobe, Japan, September 13-17, 2010. Proceedings, volume 6327 of Lecture Notes in Computer Science, pages 28–31. Springer, 2010.

[29]   Sylvain Chevillard, Mioara Joldes, and Christoph Quirin Lauter. Certified and fast computation of supremum norms of approximation errors. In Javier D. Bruguera, Marius Cornea, Debjit Das Sarma, and John Harrison, editors, 19th IEEE Symposium on Computer Arithmetic, ARITH 2009, Portland, Oregon, USA, 9-10 June 2009, pages 169–176. IEEE Computer Society, 2009.

Publications in the peer-reviewed proceedings of national conferences

[30]   Mioara Joldes, Valentina Popescu, and Warwick Tucker. Searching for sinks of Hénon map using a multiple-precision GPU arithmetic library. In Forum des Jeunes Mathématicien-ne-s, pages –6, Nov 2013.

[31]   Mioara Joldes. When a logarithm is a misspelled algorithm. In Proceedings of the Association Femmes et mathématiques, September 2010.

[32]   Florent de Dinechin, Mioara Joldes, Bogdan Pasca, and Guillaume Revy. Racines carrées multiplicatives sur FPGA. In SYMPosium en Architectures nouvelles de machines (SYMPA), Toulouse, September 2009.

Articles under submission, research reports

[33]   Mioara Joldes. Validated symbolic-numeric algorithms and practical applications in aerospace. HDR, Université Toulouse Paul Sabatier, June 2019. Available here.

[34]   Nicolas Brisebarre, Mioara Joldes, Jean-Michel Muller, Ana-Maria Nanes and Joris Picot. Error analysis of some operations involved in the Fast Fourier Transform. Under Minor Revision at ACM TOMS, 2019. Preliminary version.

[35]   Denis Arzelier, Florent Bréhard, Mioara Joldes, Jean-Bernard Lasserre, Léo Martire and Aude Rondepierre. Global Probability of Collision: Problem modeling via occupation measures. Tech. Report LAAS-CNRS, CNES Research and Transfer Contract, 2018. Hal version.

[36]   Mioara Joldes. Rigorous Polynomial Approximations and Applications. Theses, École Normale Supérieure de Lyon - ENS LYON, September 2011. https://tel.archives-ouvertes.fr/tel-00657843.