| In recent years, there has been considerable interest in the use of scripting languages as a mechanism for controlling and developing scientific software. Scripting languages allow scientific applications to be encapsulated in an interpreted environment similar to that found in commercial scientific packages such as MATLAB, Mathematica, and IDL. This improves the usability of scientific software by providing a powerful mechanism for specifying and controlling complex problems as well as giving users an interactive and exploratory problem solving environment. Scripting languages also provide a framework for building and integrating software components that allows tools to be used in a more efficient manner. This streamlines the problem solving process and enables scientists to be more productive.;One of the most powerful features of modern scripting languages is their ability to be extended with code written in C, C++, or Fortran. This allows scientists to integrate existing scientific applications into a scripting language environment. Unfortunately, this integration is not easily accomplished due to the complexity of combining scripting languages with compiled code. To simplify the use of scripting languages, a compiler, SWIG (Simplified Wrapper and Interface Generator), has been developed. SWIG automates the construction of scripting language extension modules and allows existing programs written in C or C++ to be easily transformed into scriptable applications. This, in turn, improves the usability and organization of those programs.;The design and implementation of SWIG are described as well as strategies for building scriptable scientific applications. A detailed case study is presented in which SWIG has been used to transform a high performance molecular dynamics code at Los Alamos National Laboratory into a highly flexible scriptable application. This transformation revolutionized the use of this application and allowed scientists to perform large-scale materials simulations on an day-to-day basis. In addition, a user survey is presented in which SWIG is shown to greatly simplify the creation of scriptable applications, improve productivity, and enhance the usability of scientific programs. |
