New system for indicial computation and its applications in gravitational physics
New system for indicial computation and its applications in gravitational physics
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DOI：
10.1016/s0010-4655(98)00161-1
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发表时间：
1998-12
影响因子：
6.3
通讯作者：
S. Klioner
中科院分区：
文献类型：
--
作者：
S. Klioner
EINS是用于计算索引对象(例如张量)的MATHEMICA软件包。该程序包自动处理虚拟索引和爱因斯坦求和符号，使用户能够定义新的索引对象并为这些对象分配对称性。EINS有一种基于模式匹配技术的高效简化算法，该算法充分考虑了对象的对称性和重命名虚拟索引的可能性。EINS的其他重要功能是能够自动执行隐式求和的“3+1”分割，以自然的2维形式打印表达式，并使用用户可控制的对齐命令将其导出为普通纹理或乳胶。作为EINS的一个典型应用，简要描述了在参数化后牛顿形式框架下构造大质量扩展体的局部参考系的问题。文中还简要介绍了使用EINS解决问题的方法。
EinS is a package for Mathematica intended for calculations with indexed objects (e.g. tensors). The package automatically handles dummy indices and Einstein's summation notation, enables one to define new indexed objects and to assign symmetries to that objects. EinS has an efficient simplification algorithm based on a pattern matching technique which takes full account for the symmetries of the objects and the possibility to rename dummy indices. Other important features of EinS are the ability to perform an automatically “3+1” split of implicit summations, printing expressions in a natural 2-dimensional form and exporting them into plain TEX or LATEX with user-controllable alignment commands. As a typical application of EinS, the problem of constructing of a local reference system for a massive extended body in the framework of the Parametrized Post-Newtonian formalism is briefly described. The use of EinS to solve the problem is also sketched.