The design and implementation of a large scientific code using FORTRAN 90

Abstract

Computational science has become an integral part of scientific research over the past couple of decades. From the beginnings of computing, scientists have written codes to help them solve problems. The language of choice for most scientific computing for the past 20+ years has been FORTRAN 77. However, modem advancements in programming languages, such as the idea of object-oriented programming, and other features such as dynamic memory allocation, have caused many scientific programmers to look for an alternative to FORTRAN 77. This work aims to show that Fortran 90/95 is a viable option for these scientific programmers, and although it is not fully object-oriented many of the desired features of an object-oriented language can be implemented in Fortran 90/95. This work sets out a series of design protocols and an overall programming scheme which makes writing large scientific codes more manageable. A series of specific programming tools and choices will be described which aid both the programmer and the user of the codes. Finally, some examples of the implementation of these ideas and practices will be included.