Vassil Vassilev, PhD

Research Software Engineer and IT Consultant

A motivated individual with a PhD degree in computing and experience in big data analysis frameworks. Experienced system engineer, expert in the field of compiler construction and technologies such as LLVM and Clang. Authored the C++ interpreter Cling and contributed to Clang's C++ modules adoption and implementation. Proficiency in C++, STL, ROOT, Cling, LLVM, Clang. Good communicator, acknowledged for the effective translation of problems to the generation of efficient solutions.

Bulgarian national body representative for ISO SC22 and WG21 (ISOCPP) standardization committees.


I was born in 1987 in Karlovo, Bulgaria. Graduated high school in 2006. Received my BSc in "Informatics" in 2009, MSc in "Software Technologies" in 2010 and PhD in "Computing" in 2015 from University of Plovdiv, "Paisii Hilendarski", Plovdiv, Bulgaria. I ran my own company from 2008 until 2010. In the same time was a teaching assistant in the University of Plovdiv. In 2011 made an internship at CERN and became a CERN fellow from 2012 until 2014. In 2015 became a FermiLab contractor at CERN. In 2017 became a consultant for Princeton University and from 2019 until present I am a research software engineer.


At the moment, my research interests lie in the general area of programming language design and implementation and software optimization. I am particularly interested in open, interactive and dynamic visual programming languages. Also, I am interested in developing methods for optimization/transformation of real-time computer programs, which work with large amounts of data. Last but not least, I am interested in working on broader, cutting-edge developments and design problems in the field of the software engineering.

Selected Papers

Vassilev, M., Vassilev, V. and Penev, A., 2020. IDD–A Platform Enabling Differential Debugging. Cybernetics and Information Technologies, 20(1), pp.53-67.
López-Gómez, J., Fernández, J., Astorga, D.D.R., Vassilev, V., Naumann, A. and García, J.D., 2020, February. Relaxing the one definition rule in interpreted C++. In Proceedings of the 29th International Conference on Compiler Construction (pp. 212-222).
Vassilev, V., 2016, October. Optimizing ROOT’s Performance Using C++ Modules. In Journal of Physics: Conference Series (Vol. 898, No. 10.1088, pp. 1742-6596).
Vassilev, V., Vassilev, M., Penev, A., Moneta, L. and Ilieva, V., 2015. Clad—automatic differentiation using Clang and LLVM. In Journal of Physics: Conference Series (Vol. 608, No. 1, p. 012055). IOP Publishing.
Vasilev, V., Canal, P., Naumann, A. and Russo, P., 2012, December. Cling–the new interactive interpreter for root 6. In Journal of Physics: Conference Series (Vol. 396, No. 5, p. 052071). IOP Publishing.


Selected Projects

clad, cling, ROOT, clang, llvm.

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Name : Vassil Vassilev
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Vassil Vassilev
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