Research and Development Engineer

Research and Development Engineer (M/F), the Capla Programming LanguageLevel of qualifications required : PhD or equivalentFonction : Temporary scientific engineerLevel of experience : Recently graduatedAbout the research centre or Inria departmentThe Inria Saclay-Île-de-France Research Centre was established in 2008. It has developed as part of the Saclay site in partnership with Paris-Saclay University and with the Institut Polytechnique de Paris.The centre has 40 project teams, 27 of which operate jointly with Paris-Saclay University and the Institut Polytechnique de Paris; Its activities occupy over 600 people, scientists and research and innovation support staff, including 44 different nationalities.ContextOne of the long-term goals of the ERC project Fresco1 is to turn the Rocq proof assistant into a competitive tool for doing verified computer algebra. In particular, this requires the ability to implement and formally verify well-known libraries such as GMP or BLAS/LAPACK. A significant milestone was the design of Capla,2 a safe low-level imperative language suitable for implementing such algorithms, as well as the development of a formally verified compiler for this language.It is now possible to write a library using Capla, to compile it to machine code, to verify its correctness using Rocq, and to invoke its functions from C code. There is also an ongoing postdoc work that makes it possible to invoke Capla code from the Rocq prover and to carry over the semantics of this code to Rocq proofs.Now that the project has shown its meaningfulness, it is important to ensure that the language and the compiler are both widely usable and sufficiently robust to last.The work will be carried out mainly in the Toccata team location in Gif-sur-Yvette and partly in the partner company offices in Paris. Travel expenses are covered within the limits of the scale in force.AssignmentThe primary objective of this position is to improve the language and the compiler with features that might block for wider adoption:Add support for records (i.e., C struct) to the language, as only arrays are currently supported. While adding record types does not pose any difficulty as far as the theory is concerned, it will require some tedious work to adapt the formal proofs of the compiler and of the type safety, especially if the splitting constructs from the language are extended to support records.Add support for function calls inside size expressions. Currently, only simple expressions are allowed to describe the size of an array; it is not possible to invoke functions (e.g., the absolute value). This work item is expected to be difficult and long, as it will require some large changes to the semantics and the compiler, and therefore to the formal proof. A secondary objective is to improve the Rocq formalization to make it more maintainable in the long run.Disentangle the type safety from the type checker. Currently, both are proved at once, which means that improving the type checker would break the type safety of the language. This work item requires designing algorithm-free typing rules and splitting the existing formal proof accordingly. It should be rather simple.Close the gap between the small-step semantics and the big-step semantics of Capla. The former is used for the proofs of type safety and compiler correctness, while the latter is used to prove the specification of Capla programs. The formal relation between them has been proved in only one direction, which means that, while unlikely, the big-step semantics could be vacuously correct by accident, and thus the Capla programs would be too. This work item is purely at the semantics level and does not touch the compiler. It is unclear how difficult it is.If time permits or if some of the previous items end up being unreachable, a last objective is to improve the interface with the Rocq proof assistant:Make it simpler to import Capla code inside Rocq to prove its correctness. Currently, the process involves passing a debug option to the compiler and moving some Rocq files around. Ideally, it should be possible to directly invoke the compiler from a Rocq session. This work item does not involve the semantics and the formal proofs, but it might require touching the implementation of Rocq.Note: The items above may be adjusted based on time and project needs.Main activitiesSoftware development in Rocq, development of specifications and proofs, software experimentation, writing documentation, contribution to the writing of scientific articles.SkillsKnowledge about the semantics of programming languages and their implementation is required. Knowledge of the Rocq proof assistant or of a closely-related formal system (e.g., Lean) is required. Knowledge of French is not required.Benefits packagePartial reimbursement of public transport costsLeave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)Possibility of teleworking (after 6 months of employment) and flexible organization of working hoursProfessional equipment available (videoconferencing, loan of computer equipment, etc.)Social, cultural and sports events and activitiesTheme/Domain : Proofs and Verification, Software engineering (BAP E)Warning : you must enter your e-mail address in order to save your application to Inria. Applications must be submitted online on the Inria website. Processing of applications sent from other channels is not guaranteed.Instruction to applyDefence Security :This position is likely to be situated in a restricted area (ZRR), as defined in Decree No. 2011-1425 relating to the protection of national scientific and technical potential (PPST). Authorisation to enter an area is granted by the director of the unit, following a favourable Ministerial decision, as defined in the decree of 3 July 2012 relating to the PPST. An unfavourable Ministerial decision in respect of a position situated in a ZRR would result in the cancellation of the appointment.Recruitment Policy :As part of its diversity policy, all Inria positions are accessible to people with disabilities.The candidate will be required to work with Guillaume Melquiond and also to participate in joint activities of the research team: joint seminar, working groups, etc.About InriaInria is the French national research institute dedicated to digital science and technology. It employs 2,600 people. Its 200 agile project teams, generally run jointly with academic partners, include more than 3,500 scientists and engineers working to meet the challenges of digital technology, often at the interface with other disciplines. The Institute also employs numerous talents in over forty different professions. 900 research support staff contribute to the preparation and development of scientific and entrepreneurial projects that have a worldwide impact. #J-18808-Ljbffr