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

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 associated with the null tetrad and the orthonormal tetrad quantities associated with the Ellis-MacCallum formalism. Finally, “pptype” determines the Petrov-Plebański type of the Ricci tensor.