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

Doing numerical cosmology with the Cactus code

The article presents some aspects concerning the construction of a new thorn for the Cactus code, a complete 3-dimensional machinery for numerical relativity. This thorn is completely dedicated to numerical simulations in cosmology, that means it can provide evolutions of different cosmological models, mainly based on Friedman-Robertson-Walker metric. Some numerical results are presented, testing the convergence, stability and the applicability of the code.Comment: 18 pages, 8 figures, Late

Gravity, torsion, Dirac field and computer algebra using MAPLE and REDUCE

The article presents computer algebra procedures and routines applied to the study of the Dirac field on curved spacetimes. The main part of the procedures is devoted to the construction of Pauli and Dirac matrices algebra on an anholonomic orthonormal reference frame. Then these procedures are used to compute the Dirac equation on curved spacetimes in a sequence of special dedicated routines. A comparative review of such procedures obtained for two computer algebra platforms (REDUCE + EXCALC and MAPLE + GRTensorII) is carried out. Applications for the calculus of Dirac equation on specific examples of spacetimes with or without torsion are pointed out.Comment: 20 pages, 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