0.5.0: - First version. Released 30 June 2006. 0.5.1: 23 Nov - Changed xPert.nb to accept xTensor version 0.9.0. That means changing Manifold by VBundle, essentially. Added explicit index dependencies a,b,c,d in several of the Def functions. * Released 23 Nov 2006. 8 Dec - Added Off/On[RuleDelayed::rhs] to avoid some useless messages. - Added missing definitions Perturbation[delta]=0. Thanks to Cyril Pitrou for pointing this out. * Released again on 8 Dec 2006. ------------------------------------------------------------------------ 2007 ------------------------------------------------------------------------ 0.7.0: 17 Aug - Adapted xPert.nb for xTensor.0.9.2. - Removed function xPertToCanonical because the new ToCanonical can now handle this case without tricks. 3 Sep - Added SetNumberOfArgument messages and protection. - Implemented perturbation of Weyl as given by Cyril Pitrou. 27 Oct - Added directory xPert to the CVS repository. 0.7.1: 13 Nov - Adapted xPert.nb for xTensor.0.9.3. - Some brackets are wrongly colored now. Why? ------------------------------------------------------------------------ 2008 ------------------------------------------------------------------------ 1.0.0: May-June - Full restructure of the system. Now it is much more powerful and simple. - Perturbation and GeneralPerturbation combined in a single command Perturbation taking the best of those. - Much faster algorithms to handle the Leibnitz rule and the chain rule, both for arbitrary order and arbitrary number of arguments. - Predefined formulas are now implemented in ExpandPerturbation, so that the user decides when to use them. - ExpandPerturbation now handles all index positions and covariant derivatives of perturbations. Also densities (in particular the determinant of the metric) and Lie derivatives. - Implemented Bruni's formula for a general change of gauge. - Written documentation file xPertDoc.nb. - Cleaned code. * Released on 1 July with date 30 June. ------------------------------------------------------------------------ 2009 ------------------------------------------------------------------------ 14 Dec - Added check ?InertHeadQ in the MakeBoxes definitions for Permutation, to avoid problems with the post-6 reordering rules of Mathematica. Thanks to Leo Stein for pointing this out. ------------------------------------------------------------------------ 2010 ------------------------------------------------------------------------ * Released on 10 January with version 1.0.0. ------------------------------------------------------------------------ 2011 ------------------------------------------------------------------------ 29 Jan - DefTensorPerturbation now works on scalars as well. Thanks to Leonardo Motta for reporting this issue. - Fixed documentation example DefScalarFunction[SF, 2] as now DefScalarFunction only takes one argument. - DefTensorPerturbation has the same options as DefTensor, as suggested by Leo Stein. - PerturbationOrder of the derivative of a tensor is taken as PerturbationOrder of the tensor. That is, we assume that this function is being used after expansion, when the derivatives are all of order 0. Thanks to Leo for pointing this out. 17 Apr * Released on 17 April with version 1.0.1. 30 Sep - Added messages reporting the nonstandard configuration choices of xPert. * Released on 10 October with version 1.0.2. ------------------------------------------------------------------------ 2012 ------------------------------------------------------------------------ ------------------------------------------------------------------------ 2013 ------------------------------------------------------------------------ 20 Jan - Added MakexTensions in DefMetricPerturbation, as requested by Teake. - Perturbation[Scalar[x_]] := Scalar[Perturbation[x]], as suggested by Thomas and Cyril. - GaugeChange now acts on Scalar expressions. Suggested by Cyril. - Let perturbation of scalar densities go through the general definition, which is careful about weights. Suggested by Teake. * Released on 27 January with version 1.0.3. 13 Apr - Added MetricPerturbation, as discussed with Teake. - DefMetricPerturbation has now a default for its 3rd argument. 28 Apr - Added Kernel/init.m. ------------------------------------------------------------------------ 2014 ------------------------------------------------------------------------ * Released on 15 February with version 1.0.4. 21 Sep - Use LogTrace formula for the perturbation of the determinant, as suggested by Cyril, who contributes the code as well. * Released on 28 September with version 1.0.5. ------------------------------------------------------------------------ 2015 ------------------------------------------------------------------------ * Released on 23 August again with version 1.0.5. ------------------------------------------------------------------------ 2016 ------------------------------------------------------------------------ ------------------------------------------------------------------------ 2017 ------------------------------------------------------------------------ ------------------------------------------------------------------------ 2018 ------------------------------------------------------------------------ 28 Feb - Added $RiemannSign and $RicciSign in the formulas, as reported by Leslaw Rachwal in the xAct forum. - Added perturbations for TFRicci and Kretschmann, through simple expansion into Riemann, Ricci, etc. * Released on 28 February with version 1.0.6.