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Three dimensional modelling of the peach in MAPLE

Bartoň, Stanislav (2008)

Programs and Algorithms of Numerical Mathematics

Linearized Gauss-Newton iteration method is used to determine main axes of the three-dimensional ellipsoid approximating a peach. Three independent photos displaying the peach as ground, side, and front view are used as data sources. System MAPLE 11 was used as a computer environment. A practical example is presented in order to demonstrate the usage of all required commands. The quality of approximation is evaluated as a final part of the paper.

Three-dimensional numerical model of neutron flux in hex-Z geometry

Hanuš, Milan, Berka, Tomáš, Brandner, Marek, Kužel, Roman, Matas, Aleš (2008)

Programs and Algorithms of Numerical Mathematics

We present a method for solving the equations of neutron transport with discretized energetic dependence and angular dependence approximated by the diffusion theory. We are interested in the stationary solution that characterizes neutron fluxes within the nuclear reactor core in an equilibrium state. We work with the VVER-1000 type core with hexagonal fuel assembly lattice and use a nodal method for numerical solution. The method effectively combines a whole-core coarse mesh calculation with a more...

Two implementations of the preconditioned conjugate gradient method on heterogeneous computing grids

Tijmen P. Collignon, Martin B. Van Gijzen (2010)

International Journal of Applied Mathematics and Computer Science

Efficient iterative solution of large linear systems on grid computers is a complex problem. The induced heterogeneity and volatile nature of the aggregated computational resources present numerous algorithmic challenges. This paper describes a case study regarding iterative solution of large sparse linear systems on grid computers within the software constraints of the grid middleware GridSolve and within the algorithmic constraints of preconditioned Conjugate Gradient (CG) type methods. We identify...

Verified numerical computations for large-scale linear systems

Katsuhisa Ozaki, Takeshi Terao, Takeshi Ogita, Takahiro Katagiri (2021)

Applications of Mathematics

This paper concerns accuracy-guaranteed numerical computations for linear systems. Due to the rapid progress of supercomputers, the treatable problem size is getting larger. The larger the problem size, the more rounding errors in floating-point arithmetic can accumulate in general, and the more inaccurate numerical solutions are obtained. Therefore, it is important to verify the accuracy of numerical solutions. Verified numerical computations are used to produce error bounds on numerical solutions....

Wavelet compression of anisotropic integrodifferential operators on sparse tensor product spaces

Nils Reich (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

For a class of anisotropic integrodifferential operators ℬ arising as semigroup generators of Markov processes, we present a sparse tensor product wavelet compression scheme for the Galerkin finite element discretization of the corresponding integrodifferential equations ℬ u = f on [0,1]n with possibly large n. Under certain conditions on ℬ , the scheme is of essentially optimal and dimension independent complexity 𝒪 (h-1| log h |2(n-1)) without corrupting the convergence or smoothness requirements...

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