István Faragó | Eötvös Loránd University (original) (raw)
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Advection equations appear often in large-scale mathematical models arising in many fields of sci... more Advection equations appear often in large-scale mathematical models arising in many fields of science and engineering. The Crank-Nicolson scheme can successfully be used in the numerical treatment of such equations. The accuracy of the numerical solution can sometimes be increased substantially by applying the Richardson Extrapolation. Two theorems related to the accuracy of the calculations will be formulated and proved in this paper. The usefulness of the combination consisting of the Crank-Nicolson scheme and the Richardson Extrapolation will be illustrated by numerical examples.
Two additive splitting procedures are defined and studied in this paper. It is shown that these s... more Two additive splitting procedures are defined and studied in this paper. It is shown that these splitting procedures have good stability properties. Some other splitting procedures, which are traditionally used in mathematical models used in many scientific and engineering fields, are sketched. Some conclusions, which are related to the comparison of the additive splitting procedures with the other splitting procedures, are drawn.
Journal of Computational and Applied Mathematics, 2015
Journal of Computational and Applied Mathematics, 2015
ABSTRACT Most of the models of epidemic propagations do not take into account the spatial distrib... more ABSTRACT Most of the models of epidemic propagations do not take into account the spatial distribution of the individuals. They give only the temporal change of the number of the infected, susceptible and recovered patients. In this paper we give some spatial discrete one-step iteration models for disease propagation and give conditions that guarantee some basic qualitative properties of the original process to the discrete models. Since the discrete models can be considered as the finite difference discretizations of continuous models of disease propagation given in the form of systems of partial differential equations, we can deduce conditions for the mesh size and the time step. Some of the results are demonstrated on numerical tests.
Lecture Notes in Computer Science, 2001
ABSTRACT
Lecture Notes in Computer Science, 2009
ABSTRACT The preservation of the basic qualitative properties – besides the convergence – is a ba... more ABSTRACT The preservation of the basic qualitative properties – besides the convergence – is a basic requirement in the numerical solution process. For solving the heat conduction equation, the finite difference/linear finite element Crank-Nicolson type full discretization process is a widely used approach. In this paper we formulate the discrete qualitative properties and we also analyze the condition w.r.t. the discretization step sizes under which the different qualitative properties are preserved. We give exact conditions for the discretization of the one-dimensional heat conduction problem under which the basic qualitative properties are preserved.
Lecture Notes in Computer Science, 2013
Computers & Mathematics with Applications, 2015
The paper deals with discretisation methods for nonlinear operator equations written as abstract ... more The paper deals with discretisation methods for nonlinear operator equations written as abstract nonlinear evolution equations. Brezis and Pazy showed that the solution of such problems is given by nonlinear semigroups whose theory was founded by Crandall and Liggett. By using the approximation theorem of Brezis and Pazy, we show the N-stability of the abstract nonlinear discrete problem for the implicit Euler method. Motivated by the rational approximation methods for linear semigroups, we propose a more general time discretisation method and prove its Nstability as well.
Advection equations appear often in large-scale mathematical models arising in many fields of sci... more Advection equations appear often in large-scale mathematical models arising in many fields of science and engineering. The Crank-Nicolson scheme can successfully be used in the numerical treatment of such equations. The accuracy of the numerical solution can sometimes be increased substantially by applying the Richardson Extrapolation. Two theorems related to the accuracy of the calculations will be formulated and proved in this paper. The usefulness of the combination consisting of the Crank-Nicolson scheme and the Richardson Extrapolation will be illustrated by numerical examples.
Two additive splitting procedures are defined and studied in this paper. It is shown that these s... more Two additive splitting procedures are defined and studied in this paper. It is shown that these splitting procedures have good stability properties. Some other splitting procedures, which are traditionally used in mathematical models used in many scientific and engineering fields, are sketched. Some conclusions, which are related to the comparison of the additive splitting procedures with the other splitting procedures, are drawn.
Journal of Computational and Applied Mathematics, 2015
Journal of Computational and Applied Mathematics, 2015
ABSTRACT Most of the models of epidemic propagations do not take into account the spatial distrib... more ABSTRACT Most of the models of epidemic propagations do not take into account the spatial distribution of the individuals. They give only the temporal change of the number of the infected, susceptible and recovered patients. In this paper we give some spatial discrete one-step iteration models for disease propagation and give conditions that guarantee some basic qualitative properties of the original process to the discrete models. Since the discrete models can be considered as the finite difference discretizations of continuous models of disease propagation given in the form of systems of partial differential equations, we can deduce conditions for the mesh size and the time step. Some of the results are demonstrated on numerical tests.
Lecture Notes in Computer Science, 2001
ABSTRACT
Lecture Notes in Computer Science, 2009
ABSTRACT The preservation of the basic qualitative properties – besides the convergence – is a ba... more ABSTRACT The preservation of the basic qualitative properties – besides the convergence – is a basic requirement in the numerical solution process. For solving the heat conduction equation, the finite difference/linear finite element Crank-Nicolson type full discretization process is a widely used approach. In this paper we formulate the discrete qualitative properties and we also analyze the condition w.r.t. the discretization step sizes under which the different qualitative properties are preserved. We give exact conditions for the discretization of the one-dimensional heat conduction problem under which the basic qualitative properties are preserved.
Lecture Notes in Computer Science, 2013
Computers & Mathematics with Applications, 2015
The paper deals with discretisation methods for nonlinear operator equations written as abstract ... more The paper deals with discretisation methods for nonlinear operator equations written as abstract nonlinear evolution equations. Brezis and Pazy showed that the solution of such problems is given by nonlinear semigroups whose theory was founded by Crandall and Liggett. By using the approximation theorem of Brezis and Pazy, we show the N-stability of the abstract nonlinear discrete problem for the implicit Euler method. Motivated by the rational approximation methods for linear semigroups, we propose a more general time discretisation method and prove its Nstability as well.