PrefaceThis work is an interdisciplinary effort and would not have been possible without many contributions from different sources. My gratitude goes to:Peter Bastian who laid the basis to this work in many different ways and always supported me. I couldn't think of a better teacher of the art of scientific computing.Gabriel Wittum for recognizing the importance of scientific software development, his support and for sharing my Macintosh enthusiasm.Rainer Helmig generously supported my work. Working with him and his group was always a pleasure.The other members of the ug development team for their work: