1. Faculty of Mathematics, University of Vienna, Kolingasse 14–16, 1090 Vienna, Austria ().
2. Skolkovo Institute of Science and Technology, Novaya Ul. 100, 143025 Skolkovo, Moscow Region, Russia and Institute of Numerical Mathematics, Russian Academy of Sciences, Gubkina St. 8, 119333, Moscow, Russia ().
3. HSE University, Pokrovsky Boulevard 11, Moscow, 109028 Russia ().
4. Seminar for Applied Mathematics, ETH Zurich, Rämistrasse 101, 8092 Zurich, Switzerland ().