wedge / News: Recent posts

The latest version of Wedge is available at https://github.com/diego-conti/wedge

This is a maintenance release, for compatibility with GiNaC 1.5.1. Some performance tests have been added which indicate a gain in performance with the use of the new GiNaC version. Also added a new example related to the computations contained in the paper http://arxiv.org/abs/0903.1175.

This release introduces support for explicit Lie algebra representations; it also contains some bugfixes and minor improvements.

This is a maintenance release containing some bugfixes in the install scripts. The main novelty is that this version compiles on Solaris and Cygwin.

An expository paper describing some of the functionality implemented by Wedge is now available at http://arxiv.org/abs/0804.3193

Version 0.2.1 is now available, with a few bugfixes and improvements, new examples, and support for Riemannian submersions.

This release is comparatively more reliable than the 0.1.x versions, but still labeled alpha.

Beside several bugfixes, these are the main changes:
- added more examples
- introduced AffineBasis, a container for affine equations that performs automatic reduction (replacing AffineSpace)
- introduced support for connections on a ManifoldWith

Wedge 0.1.2 has been released.

This version introduces Lie derivatives.

Version 0.1.1 has been released, with one new example and fixes in the installation scripts.

A detailed list of changes follows:
- Fixes in configure.ac and Makefile.am
- Changed the behaviour of NormalForm<Lambda<V>> and GetComponents<Lambda<V>> to allow scalar components (i.e. passing an argument like 1+v+v*w does not cause an exception anymore)
- Added a more complex example (Dictionary)
- Function isOdd now accepts mixed-degree arguments

Here is a list of the current features of Wedge:
- Vector spaces: determine a basis from a list of generators, and similar computations.
- Manifolds and differential forms: exterior derivative; wedge product.
- Lie groups: the general linear group; subgroups determined by the choice of a subalgebra; abstract Lie groups defined in abbreviated form, e.g. writing (0,0,12) for the Heisenberg group, characterized by the existence of a basis of left-invariant one-forms e1,e2,e3 such that de3=e1 ^ e2 and e1,e2 are closed.
- Riemannian metrics and G-structures, defined on a Lie group or a coordinate patch of a generic manifold, and represented by an orthonormal basis of 1-forms (adapted frame); spinors, Clifford multiplication.
- Connections: the Levi-Civita connection; curvature; covariant derivatives; define connections on generic manifolds and impose conditions on the Christoffel symbols, e.g. to obtain curvature conditions.
- LaTeX output.