Maple+GrTensorII libraries for cosmology

The article mainly presents some results in using MAPLE platform for computer algebra and GrTensorII package in doing calculations for theoretical and numerical cosmologyComment: LaTeX LLNCS style, 8 pages, accepted for SYNASC 2004 - 6th International Symposium on Symbolic and Numeric Algorithms for Scientific Computing, Timisoara, Romania, September 26-30 200

Classical Oscilators in General Relativity

It is shown that in general relativity some static metrics are able to simulate oscillatory motions. Their form depends on two arbitrary real parameters which determine the specific oscillation modes. The conclusion is that these metrics can be used for new geometric models of closed or even open bags. Pacs: 04.02.-q and 04.02.JbComment: Latex, 10 page

Testing the Cactus code on exact solutions of the Einstein field equations

The article presents a series of numerical simulations of exact solutions of the Einstein equations performed using the Cactus code, a complete 3-dimensional machinery for numerical relativity. We describe an application (``thorn'') for the Cactus code that can be used for evolving a variety of exact solutions, with and without matter, including solutions used in modern cosmology for modeling the early stages of the universe. Our main purpose has been to test the Cactus code on these well-known examples, focusing mainly on the stability and convergence of the code.Comment: 18 pages, 18 figures, Late

The use of Maple platform for the study of geodisc motion on curved spacetimes

The article illustrates the graphical study of geodesic motion on curved space-times (mainly exact solutions of Einstein equations) using the symbolic, numerical and graphical computation facilities of Maple platform. The example of null geodesics on Schwarzschild solution is completely processed. The geodesic curves are plotted directly using DEtools package in Schwarzschild coordinates