**Guri Marchuk** was a Russian mathematician who worked in the fields of computational mathematics and the physics of the atmosphere.

- In his last year at the High School in Dukhovnitskoye, 1941-42, Guri worked as an assistant to the combine operator.
- It was there that Marchuk began his studies but in 1943 he was drafted into the army and sent to the Artillery Military Intelligence school.
- After graduating from Leningrad State University in 1949, Marchuk entered graduate school, showing a deep interest in the problems of atmospheric physics, undertaking research at the Geophysical Institute of the Academy of Sciences of the USSR.
- In 1952 Marchuk defended his Candidate's thesis (equivalent to a Ph.D.) titled "Dynamics of large-scale fields of meteorological elements in a baroclinic atmosphere" (Russian).
- It was only on the following day that he learned that the director at the 'object' was Dmitrii Ivanovich Blokhintsev (1908-1979), and that he would be working in the department of Evgraf Sergeevich Kuznetsov (1901-1966); both these names were well known to him.
- Marchuk worked at the Physics Energy Institute at Obninsk from 1952 and, from 1953 to 1962, he was head of the Department of Mathematics at the Institute.
- Marchuk proposed new methods for nuclear reactor calculations and even nowadays these form the basis of mathematical modelling and imitative calculations.
- In 1956 Marchuk submitted his doctoral thesis Numerical methods for nuclear reactor calculations (Russian).
- This book led to Marchuk becoming a leading scientist being recognised for his achievements both in the Soviet Union and internationally.
- After his work on the hydrogen bomb, Marchuk switched to creating a new class of submarines with liquid metal coolant for reactors, which had no analogue in the world so far.
- In 1962 Marchuk began a new phase in his career when he was asked by Mikhail Alekseevich Lavrentev and Sergei Lvovich Sobolev to set up a Computing Centre for the Institute of Mathematics in the Siberian Branch of the USSR Academy of Sciences.
- Marchuk continually organized working scientific seminars, thematic conferences, and symposia on these topics.
- Soon the group headed by Marchuk became the foremost academic centre in Siberia for research in computational mathematics and one of the most important in our country and abroad.
- In 1966 the International Congress of Mathematicians was held in Moscow and Marchuk was one of the invited speakers.
- Marchuk gave a plenary lecture to the International Congress of Mathematicians in Nice, France, in 1970.
- Marchuk contributed much to the development of splitting methods and perturbation algorithms based on adjoint equations.
- In the design of nuclear reactors, on the basis of the theory of adjoint equations and perturbation algorithms, Marchuk developed the construction principles for effective multigroup models of nuclear reactors, created mathematical reactor models in various spherical harmonic approximations, and proposed numerical schemes for solving arising equations.
- Marchuk contributed much to numerical weather prediction and the modelling of the atmosphere and ocean general circulation, climate, and its changes.
- Considerable contributions were made by Marchuk to the creation of the theory of mathematical modelling of optimization problems in environmental protection.
- In many of his studies, Marchuk addressed mathematical modelling in immunology and medicine.
- Marchuk has written, or edited, a very large number of books.
- In 1968 Marchuk was elected a full member of the USSR Academy of Sciences; in the following year he became the Deputy Chairman of the Executive Committee of the Siberian Branch of the USSR Academy of Sciences and, in 1975, he became Chairman of that Executive Committee.
- Marchuk served as President of the USSR Academy of Sciences from 1986 to 1991 and, when his period of office ended, became an Honorary Member of the Executive Committee of the Russian Academy of Sciences.
- Marchuk was, therefore, the last President of the USSR Academy of Sciences.
- In the year 2000, Marchuk greeted the new century with a speech in which he said the 20th century was the "triumph of physics" while in the 21st century he expected outstanding breakthroughs in the life sciences.
- Marchuk received honorary doctorates from the University of Toulouse (1973), Charles University of Prague (1978) Dresden Technical University (1981), the Technical University of Budapest (1982), Calcutta University (1988), Tel Aviv University (1990), and Houston University (1992).
- There are other ways that Marchuk has received recognition such as a street in Dukhovnitskoye being named for him, a memorial plaque being placed on the building of the Institute of Computational Mathematics and Mathematical Geophysics in the Siberian Branch of the Russian Academy of Sciences on 19 June 2015, and a bust of Marchuk being installed in the park of the district of Dukhovnitsky on 2 September 2019.

Born 8 June 1925, Petro-Khersonets, Grachevka district, Orenburg, Russia. Died 24 March 2013, Moscow, Russia.

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Origin Russia

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive