Issue N^{o} 1, 1990 
ENHANCEMENT OF THE PROGRAM SUPPORTING SYSTEM CAPABILITIES
A.S. Kisel, V.A. Kubyak, V.I. Legonkov, A.M. Yaroshevskiy VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 36.
The capabilities of a supporting system for programs are discussed. New language aids added during the experimental operation of the system are described, namely, the description of data structure and access functions. Information about the true portability and advantages provided within a system of programs is given. Some ways of the further development of the system are outlined.

CONSTRUCTION OF DIFFERENCE MESHES BY OPTIMIZING PARAMETERS FOR INTERPOLATION FORMULAS G.P. Prokopov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 716.
The simplest interpolation method of constructing a difference mesh is considered to enhance its capabilities owing to different ways of setting the governing parameters. Several options of setting the governing parameters using explicit formulas and a numerical algorithm of optimizing them developed on the basis of actual variational functionals are described. The algorithm allows verifying functionals of various forms. The interpolation method allows natural generalization to a spatial case.

COEFFICIENTS OF REGULAR ANGULAR DISTRIBUTION OF ISOTROPIC RADIATION FOR CUBOOCTAHEDRAL CELLS OF THE FIRST AND SECOND NEIGHBORHOOD LEVELS E.G. Vasina, Yu.A. Dementev VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 1719.
An isotropic source located at the central point of a fixed cell in a regular spatial mesh of cubooctahedrons is studied. Coefficients are calculated for the angular distribution of the central source energy in 14 or 50 directions connecting a fixed cell with cells of the first, or second neighborhood levels. For the calculation of solid angles, surfaces of cells are approximated with spheres.

ABOUT ONE SCHEME OF THE MONTE CARLO METHOD FOR THEMONUCLEAR NEUTRON SPECTRUM SIMULATIONS A.I. Morenko VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 2023.
The paper proposes a scheme to simulate a spectrum of thermonuclear neutrons, which is based on the spectrum factorization with respect to densities describing the anisotropy of reaction products in the centerofmass system. With such factorization, the Monte Carlo simulation of the spectrum is performed for the selected continuous distributions, rather than separate particles. This provides the method stability in selecting and refining a grid for drawing results, improves the monotonicity of results and allows obtaining satisfactory results with a much smaller number of simulated particles.

THE SERIVICE SYSTEM OF ONEDIMENSIONAL SOFTWARE SYSTEM ON UNIFIED COMPUTER SYSTEM E.G. Voronov, M.I. Kaplunov, S.V. Rebrov, V.G. Ryshikh, V.I. Filatov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 2431.
The paper gives a general description of the service system in the software package used to solve 1D problems in computational physics on the unified computer system (OKES). The purpose, properties and ways of using the OKES objects are described. The structure and functions of the service in 1D complex on the unified computer system are discussed and the OKES functionality is described.

THE IMPROVED POLYNOMIAL REPRESENTATION FOR DELTASHAPED SCATTERING INDICATRICES A.D. Gadzhiev, S.B. Serov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 3234.
Basing on the improved polynomial representation for the σfunction, the improved P_{N}approximation is constructed for highstretched scattering indicatrices. This problem arises when solving the transport equation with highly anisotropic particle scattering. The improved polynomial representation has a number of advantages over the traditional P_{N}approximation, the major of them is the positivity property. The paper presents formulas of the improved P_{N}approximation for σshaped indicatrices. The P_{N}approximation is graphically compared with the improved polynomial approximation for the σfunction.

A FUNDAMETAL SYSTEM OF SOLUTIONS TO THE EQUATION OF ONEDIMENSIONAL PLANE ISENTROPIC FLOWS OF A POLYTROPIC GAS V.E. Shemarulin VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 3540.
The velocity potential equation describing onedimensional plane isentropic flows of a polytropic gas is linearized using the classic Legendre transformation (hodograph). For the linear equation in the hodograph variables, a fundamental system of uniform polynomial solutions has been found, which is used for the global solution of Cauchy problem in the hodograph plane. A general method of constructing explicit formulas representing the polynomial solution factors via binomial factors is given. Recursion operators are given for the linear equation. The gas flows described by the fundamental polynomials of small degrees have been studied in details figures.

THE RHOMB METHOD FOR NUMERICALLY SOLVING THE 2D RADIATION TRANSPORT EQUATION IN MULTIGROUP P_{1}APPROXIMATION A.D. Gadzhiev, A.A. Shestakov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 4147.
The paper describes the use of the finitedifference RHOMB method for numerically solving 2D unsteady equations of radiation transport in multigroup P_{1}approximation. The twostage iterative Jacobi method is used for jointly solving the multigroup system of P_{1}equations and the energy equation.

ON THE SIMULATION OF THE FOREST FIRE DETONATION MODEL USING THE DIFFERENCE GODUNOV METHOD Yu.N. Deryugin, V.P. Kopyshev, M.M. Proshin, B.P. Tikhomirov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 4852.
The feasibility of using the difference Godunov method to simulate the FOREST FIRE model of detonation on a motionless Eulerian grid is studied. For the sake of simplicity, the numerical study is performed for a onedimensional case. Basing on the FOREST FIRE model of detonation, the numerical technique is developed to simulate the shockwave initiation and detonation development and verified on a model problem. For comparison, the results calculated using the fully conservative difference scheme are given.

TWO EXAMPLES OF CONSTRUCTING GRIDS OF CONVEX QUADRANGLES S.A. Ivanenko, A.A. Cherakhchyan VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 5356.
The paper offers two test problems to verify the serviceability of algorithms in regions with strongly distorted boundaries. A quadrangular grid has been constructed in the regions of interest by minimizing some function describing the convexity of the grid.

“ALGOL GDR – PL/I” CONVERTOR V.V. Bumagin, A.I. Kondrashenko VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 5763.
The paper describes the convertor from the input language ALGOLGDR to PL/I. The convertor specifications are given. The original language subset is described for the guaranteed translation into PL/I. The convertor operation practice is analyzed. It is demonstrated that with the appropriate translation of programs the convertor allows significantly lowering the programmer labor inputs.

THE SOURCE FUNCTION IN THE PROBLEM OF A CONFINED EXPLOSION I.V. Gorev, V.I. Selin VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 6468.
The problem of calculating the source function of seismic waves in an underground explosion is considered. The paper describes the calculation procedure, discusses the calculated and empirical ratios between the elastic zone radius and the explosive source parameters, and touches upon the subject of the source function analytical approximation.

ABOUT THE EIGENVALUE PROBLEM SOLUTION FOR A SYSTEM OF ORDINARY DIFFERENTIAL EQUATIONS OF THE METHOD OF MULTIDIMENSIONAL ANGULAR COULOMB FUNCTIONS USING STURM EXPANSIONS WITH EMPHASIS ON ASYMPTOTICS A.A. Sadovoy, V.M. Povyshev VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 6972.
The paper offers the way of solving the eigenvalue problem for a system of secondorder ordinary differential equations of the method of multidimensional angular Coulomb functions, which is based on Sturm expansions with emphasis on asymptotics. The computational algorithm of solving the generalized eigenvalue problem uses the LUfactorization of matrices and the method of inverse iterations. The proposed method convergence was analyzed.

VARIOUS FORMS OF A 3D KINETIC EQUATION IN CURVILINEAR SPHERICAL AND CYLINDRICAL COORDINATES S.B. Serov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 7375.
The paper considers various ways of writing a threedimensional kinetic equation in coordinate systems of the spherical and cylindrical types. It presents a 3D transport equation written in one practically important curvilinear system of coordinates.

A MODEL OF LASER RADIATION ABSORPTION AND ENERGY OUTPUT OF “HOT” ELECTRONS IN SPHERICAL PLASMA S.A. Belkov, S.N. Gayduk, S.G. Garanin, G.V. Dolgoleva, G.G. Kochemasov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 7683.
A model of laser radiation absorption and energy output of “hot” electrons in spherical plasma has been formulated and implemented in the SND gas dynamic code. The model accounts for the density profile steepening processes under the effect of a ponderomotive force, plasma heating by “hot” electrons, and the absorbed energy losses to accelerate “fast” ions.

CONVERSION OF TEXTUAL COMMANDS INTO THEIR TABULAR FORMS N.P. Veldyaksov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 8489.
The paper considers the issues of converting (transforming) textual commands into tabular commands in the form of data structures. The convertor implemented in one file system is described. The issues of the command text analysis – syntax checking, setting the withhold values for missed operands (parameters), checking operands for belonging to tolerance region, as well as the issues concerning the construction of tables corresponding to commands are considered. The descriptions are used in the converting process to analyze a command and construct a table. The development of such descriptions is an easy to implement process, as compared to the program convertor modification.

ABOUT DIFFERENCE SCHEMES FOR PARABOLIC EQUATIONS UNSTABLE IN UNIFORM NORM N.Yu. Bakaev, V.V. Vyazankin VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 9091.
The paper gives examples of difference schemes for the simplest parabolic equation, which are stable in L_{2h}, but unstable in C_{h}.

AN ALGORITHM OF RECONSTRUCTING A DISCRETE SEQUENCE OF INITIAL EXPOSURE USING THE MODIFIED TELEMETRIC DATA AND PARAMETERS OF CONVERTER Yu.L. Dmitrakov VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 9293.
With the use of Kotelnikov’s theorem, an algorithm of processing the discretized telemetric data that allows reconstructing the controlled factor dependence on time using the converter parameters has been developed.

A SET OF PROGRAMS FOR SIMULATION OF TRANSIENT PROCESSES IN ELECTRICAL CIRCUITS OF AUTOMATIC DEVICES AND SYSTEMS A.N. Lipatov, V.M. Pravdukhin VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 9496.
The paper describes the POLET program system for the simulation of electrical circuits in automatic equipment. The specific features of the input language and algorithms used in the program system are described, which represent the specifics of components and nature of transient processes in the automatic equipment circuits. Prospects for the further development of the POLET program system are outlined.

ESTIMATION OF THE MODULAR PIPELINED PROCESSOR PERFORMANCE N.N. Vyskubenko, G.A. Danilov, A.M. Sorvachev VANT. Ser.: Mat. Mod. Fiz. Rroc. 1990. No 1. P. 97100.
The paper presents data on the rated performance of MPP of the “Elbrus 31” computing system, as well as the estimates and performance measurement results obtained using test problems for the simulation of the main cycle of computations in solving the heat conduction equations and equations of state for solid materials, and the synthetic test for MVK “Elbrus2” (multiprocessor computing system), computers BESM6, EC1066, “Elbrus IK12”, and CONVEXC1.

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