  |
Ricci - http://www.math.washington.edu/~lee/Ricci/
A Mathematica package for doing tensor calculations in differential geometry and general relativity. |
  |
GRTensorII - http://grtensor.org/
A computer algebra package for performing differential geometry calculations. Demonstrations of the package's applications to general relativity. |
  |
GRAVLENS - http://redfive.rutgers.edu/~keeton/gravlens/
Software for modelling gravitational lens systems; created and maintained by Chuck Keeton at Rutgers University. |
  |
Whisky - http://www.whiskycode.org/
A code to evolve the equations of hydrodynamics in curved spacetime (relativistic numerical hydrodynamics). |
  |
Kranc - http://numrel.aei.mpg.de/Research/Kranc/
A suite of Mathematica packages for numerical relativists, which helps with tasks such as performing 3+1 decompositions, analytical manipulations of tensorial systems of equations (such as change of variables), computation of characteristics or linearizations, and automatic code generation. |