The maple package NPTOOLS; a symbolic algebra package for tetrad formalisms in general relativity

Abstract In this paper, we present and discuss the NPTOOLS package written for the computer algebra system Maple. The package contains the main routines “nulltran”, “inv”, “nullor”, “ornull” and “pptype”. The routine “nulltran” is an implementation of the 6-parameter Lorentz group in the Newman-Penrose (null tetrad) formalism, and “inv” checks for invariance of equations under subgroups of the Lorentz group. The routines “nullor” and “ornull” provide a translation between the Newman-Penrose quantities... Title of program: NPTOOLS Catalogue Id: ADJM_v1_0 Nature of problem There are three main sections to the NPTOOLS program. The first of these provides a translation between the physical quantitites of the orthonormal tetrad formalism of Ellis [2,3] and MacCallum [5] and the null tetrad quantities of the Newman-Penrose [6] formalism. The second provides an implementation of the 6-parameter Lorentz group and has a facility for checking the invariance of Newman-Penrose equations under subgroups of the Lorentz group. This part of the program proved useful as an aid i ... Versions of this program held in the CPC repository in Mendeley Data ADJM_v1_0; NPTOOLS; 10.1016/S0010-4655(98)00163-5 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)