Personal page of Guillaume Iooss

I am a researcher at Inria (CRCN in team CORSE in Grenoble).

My topics of interest are polyhedral compilation, high-performance computing and synchronous compilation. More precisely, I work on the polyhedral model, on the tiling transformation, on program equivalence (and using semantic properties in a compiler) and on synchronous languages.

Contact informations:

• Professional email:
• (Outdated) Work office: C334 - Campus Minatec - Grenoble
• I am also on Github

Research

List of publications

• Journal articles:
  • Nicolas Tollenaere, Guillaume Iooss, Stéphane Pouget, Hugo Brunie, Christophe Guillon, Albert Cohen, P. Sadayappan and Fabrice Rastello. Autotuning Convolutions Is Easier Than You Think. In ACM Transactions on Architecture and Code Optimization (TACO). Volume 20, Issue 2. January 2022.
  • Guillaume Iooss, Christophe Alias and Sanjay Rajopadhye. Monoparametric Tiling of Polyhedral Programs. In International Journal of Parallel Programming (IJPP). March 2021.
  • Keryan Didier, Dumitru Potop-Butucaru, Guillaume Iooss, Albert Cohen, Jean Souyris, Philippe Baufreton, and Amaury Graillat. Correct-by-Construction Parallelization of Hard Real-Time Avionics Applications on Off-the-Shelf Predictable Hardware. In ACM Transactions on Architecture and Code Optimization (TACO), Volume 16, Number 3. August 2019.
• International conference:
  • Lionel Eyraud-Dubois, Guillaume Iooss, Julien Langou and Fabrice Rastello. Tightening I/O Lower Bounds through the Hourglass Dependency Pattern. In Proceedings of the 36th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA'24). Nantes, France, June 2024. (slides)
  • Guillaume Iooss, Albert Cohen, Dimitru. Potop-Butucaru, Marc Pouzet, Vincent Bregeon, Jean Souyris and Philippe Baufreton. Polyhedral Scheduling and Relaxation of Synchronous Reactive Systems. In 12th International Workshop on Polyhedral Compilation Techniques (IMPACT'22), Budapest, Hungary, June 2022. (slides)
  • Nicolas Derumigny, Théophile Bastian, Fabian Gruber, Guillaume Iooss, Christophe Guillon, Louis-Noël Pouchet, Fabrice Rastello. PALMED: Throughput Characterization for Superscalar Architectures. International Symposium on Code Generation and Optimization (CGO), Seoul, South Korea, Avril 2022.
  • Auguste Olivry, Guillaume Iooss, Nicolas Tollenaere, Rui Li, Atanas Rountev, P. Sadayappan, Fabrice Rastello. IOOpt - Automatic Derivation of I/O complexity bounds for affine programs. In ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI 2021)
  • Christophe Alias, Guillaume Iooss, Sanjay Rajopadhye. On the Verification of Polyhedral Program Transformation. In the 3rd Special Session on Compiler Architecture, Design and Optimization (CADO2020, special session of HPCS2020)
  • Philippe Baufreton, Vincent Bregeon, Keryan Didier, Guillaume Iooss, Dumitru Potop, Jean Souyris. Efficient fine-grain parallelism in shared memory for real-time avionics (ERTS² 2020).
  • Jean Souyris, Keryan Didier, Dumitru Potop, Albert Cohen, Timothy Bourke, Guillaume Iooss and Marc Pouzet. Automatic Parallelization from Lustre Models in Avionics (ERTS² 2018)
  • Guillaume Iooss, Christophe Alias, and Sanjay Rajopadhye. On program equivalence with reductions. In 21st International Static Analysis Symposium (SAS'14), Munich, Germany, September 2014.
  • Lucas W. Krakow, Louis Rabiet, Yun Zou, Guillaume Iooss, Edwin K. P. Chong, and Sanjay Rajopadhye. Optimizing dynamic resource allocation. In Proceedings of the International Conference on Computational Science, ICCS 2014, Cairns, Queensland, Australia, 10-12 June, 2014, pages 1277--1288, May 2014.
  • Guillaume Iooss, Sanjay Rajopadhye, Christophe Alias, and Yun Zou. CART: Constant aspect ratio tiling. In 4th International Workshop on Polyhedral Compilation Techniques (IMPACT'14), Vienna, Austria, January 2014. (Slides)
  • Yun Zou, Guillaume Iooss, and Sanjay Rajopadhye. Compilation of structured polyhedral equations. In 17th Workshop on Compilers for Parallel Computing (CPC'13), July 2013.
  • Guillaume Iooss and Sanjay Rajopadhye. A library to manipulate Z-polyhedra in image representation. In 2nd International Workshop on Polyhedral Compilation Techniques (IMPACT'12), Paris, France, January 2012.
• Technical report:
  • Nicolas Tollenaere, Auguste Olivry, Guillaume Iooss, Hugo Brunie, Albert Cohen, P. Sadayappan, Fabrice Rastello. Efficient convolution optimisation by composing micro-kernels. February 2021.
  • Nicolas Derumigny, Fabian Gruber, Théophile Bastian, Guillaume Iooss, Christophe Guillon, Louis-Noel Pouchet, Fabrice Rastello. From micro-OPs to abstract resources : constructing a simpler CPU performance model through microbenchmarking. November 2020.
  • Guillaume Iooss, Marc Pouzet, Albert Cohen, Dumitru Potop-Butucaru, Jean Souyris, Philippe Baufreton. 1-Synchronous Programming of Large Scale, Multi-Periodic Real-Time Applications with Functional Degrees of Freedom. February 2020
  • Keryan Didier, Dumitru Potop-Butucaru, Guillaume Iooss, Albert Cohen, Jean Souyris, Philippe Baufreton, Amaury Graillat. Parallelisation efficace de larges applications temps-reel. Research Report, RR-RR-9180, INRIA, 2018.
  • Tian Jin, Nirmal Prajapati, Waruna Ranasinghe, Guillaume Iooss, Yun Zou, Sanjay Rajopadhye and David G. Wonnacott. Hybrid Static/Dynamic Schedules for Tiled Polyhedral Programs. Research Report, 2016
  • Guillaume Iooss, Sanjay Rajopadhye, Christophe Alias, Yun Zou. Mono-parametric Tiling is a Polyhedral Transformation. Research Report, RR-8802, INRIA, 2015.
  • Sanjay Rajopadhye, Guillaume Iooss, Tomofumi Yuki, and Dan Connors. The stencil processing unit: GPGPU done right. Technical report, Colorado State University, March 2013.
  • Tomofumi Yuki, Vamshi Basupalli, Gautam Gupta, Guillaume Iooss, DaeGon Kim, Tanveer Pathan, Pradeep Srinivasa, Yun Zou, and Sanjay Rajopadhye. AlphaZ: A system for analysis, transformation, and code generation in the polyhedral equational model. Technical report, Colorado State University, May 2012.
• PhD: Detection of linear algebra operations in polyhedral programs
  • My PhD was a cotutelle between ENS Lyon (advisers: Christophe Alias, Alain Darte/ team: Compsys) and Colorado State University (adviser: Sanjay Rajopadhye / team: Melange).
  • Dissertation / Slides of the defense
• Short paper and posters:
  • Poster Hipeac 14 (Constant Aspect Ratio Tiling)
  • Poster Hipeac 13 (Semantic Tiling)
  • Guillame Iooss, Sanjay Rajopadhye, and Christophe Alias. Semantic tiling. In Workshop on Leveraging Abstractions and Semantics in High-performance Computing (LASH-C), Shenzhen, China, February 2013.
• Dissemination:
  • IO Complexity, 1h introducting seminar on IO-complexity, IOLB and Ioopt, targeting the L3 students of ENS Lyon in 2022.
  • Poly-exo, a collection of short lessons and introducing exercises to the polyhedral model (July 22: currently in construction)

Software

• Library implementing the basic mathematical operations for the monoparametric partitioning transformation: Github repository (integrated inside a C compiler)
• Various transformations in the AlphaZ compiler
• Various transformations in the Heptagon compiler (especially inside the "onesync", and the "opencl-redefine" branches)
• Contributions to the IOLB tool, online demo webpage can be found here.
• Contributions to Ttile, a code generator and strategy explorer for tensor-like operations (convolution, matrix multiplication, tensor contraction)

Community service

• Impact 2021 - PC member
• Impact 2020 - Co-organizer
• Impact 2019 - PC member
• Impact 2018 - PC member

Teaching (TD/TP):

• (2021-2023) INF301 - Algorithmique et Programmation Impérative (L2 - UGA)
• (2020-2021) Base de la Programmation (L3 - Ensimag)
• (2019-2020) Circuit et Architecture des ordinateurs (M1 - Université Paris Diderot)
• (2017-2018) Compilation (L2 - IUT Orsay)
• (2017-2018) Projet Nao (robotique) (L2 - IUT Orsay)
• (2013-2014) Image (M1 Ens Lyon)
• (2013-2014) LIF3: algorithmique et programmation fonctionnelle et récursive (L1 - Université Lyon 1)
• (2013-2014) Théorie de la programmation (L3 Ens Lyon)
• (2012-2013) Image (M1 Ens Lyon)
• (2012-2013) Compilation (M1 Ens Lyon)