We use an all–sky, complete sample of nearby galaxies, extracted from the LEDA data base, to map the optical galaxy density field in the nearby universe. In order to determine this field, we correct the redshift–dependent distances by testing some peculiar velocity field models and we correct the galaxy number density for the incompletion of the galaxy sample at large distances through the deri...

The Exact Geometric Computation (EGC) mode of computation has been developed over the last decade in response to the widespread problem of numerical non-robustness in geometric algorithms. Its technology has been encoded in libraries such as LEDA, CGAL and Core Library. The key feature of EGC is the necessity to decide zero in its computation. This paper addresses the problem of providing a fou...

Multi-paradigm software development is a possible answer to attempts of finding the best paradigm. It was present in software development at the level of intuition and practiced as the “implementation detail” without a real support in design. Recently it is making a twofold breakthrough: several recent programming paradigms are encouraging it, while explicit multi-paradigm approaches aim at its...

This paper describes progress in the design and testing of the log-ratio-based beamposition/intensity measurement module being built for the Low Energy Demonstration Accelerator (LEDA) and Accelerator Production of Tritium (APT) projects at Los Alamos National Laboratory. The VU-based module uses four, 2 MHz if inputs to perform two-axis position measurements and one intensity measurement. To c...

LEDA is a library of efficient data types and algorithms. At present, its strength is graph algorithms and related data structures. The computational geometry part is evolving. The main features of the library are • a clear separation of specification and implementation • parameterized data types • its extendibility • its ease of use. At present, the data types stack, queue, list, set, dictiona...

This paper discusses the design, fabrication and testing of a high power alumina disk window in WR1500 waveguide at L Band, suitable for use in the NLC damping ring RF cavities at 714 MHz and the LEDA Accelerator at 700 MHz. The design is based on the fabrication methods used for the successful PEP-II cavity windows. Four prototype windows at 700 MHz have been produced by LBNL for testing at LA...

In contrast to other areas of mathematics such as calculus, number theory or probability theory, there is currently no standard library for graph theory for the Isabelle/HOL proof assistant. We present a formalization of directed graphs and essential related concepts. The library supports general infinite directed graphs (digraphs) with labeled and parallel arcs, but care has been taken not to ...

We present a new algorithm to solve the 3-dimensional width problem, i.e. to determine two parallel planes of smallest distance such that the region between the two planes contains a given point set. Like the algorithm of Houle and Toussaint, our method has quadratic worstcase complexity but is much faster in practice. In contrast to Houle and Toussaint, we do not use plane sweep or point locat...