http://www.npac.syr.edu/users/haupt/bbh/PITT_CODES Gravitational Wave Extraction <description><url>http://www.npac.syr.edu/users/haupt/bbh/PITT_CODES/intro/pitt.html</url> <abstract> Gravitational wave extraction is one of the important aspects of the computational grand challenge program. There are two schools of thought when it comes to implementing the extraction of gravitational waves from a numerically generated spacetime. One way is to simply let the waves propogate via standard Cauchy devolopment (evolving spatial surfaces using the standard initial value formulation). One of the major drawbacks with this method is that a very large computational grid is needed to allow the waves to propogate far from the source. The other way to study radiation far from the source is to use an initial value formulation based on ``characteristic surfaces.'' This is the technique developed by the Pittsburgh group. It should be stressed that the code does not deal with gravitational waves. The code evolves a scalar field on a flat, background, spacetime via the standard linear wave equation. It is the hope of the Pittsburgh group that the code will be generic enough to incorporate evolving gravitational waves later. <keywords>cosmology; spacetime; gravitational interaction; application program <category>application <contact>Tom Haupt / haupt@npac.syr.edu </urc>