Fortran portability via models and tools

  • W. S. Brown
  • A. D. Hall
Conference paper

DOI: 10.1007/3-540-08446-0_41

Part of the Lecture Notes in Computer Science book series (LNCS, volume 57)
Cite this paper as:
Brown W.S., Hall A.D. (1977) Fortran portability via models and tools. In: Cowell W. (eds) Portability of Numerical Software. Lecture Notes in Computer Science, vol 57. Springer, Berlin, Heidelberg

Abstract

This talk is a survey of recent Bell Labs work on FORTRAN-based software portability. Our approach is based on our experience with the ALTRAN language and system for symbolic algebra, and the PORT Library of state-of-the-art procedures for numerical mathematics.

Both ALTRAN and PORT are written in PFORT, a large and mechanically verifiable subset of ANS FORTRAN. To make PFORT programs easier to write and easier to read, we now use an extension called RATFOR and a preprocessor that translates it into PFORT. A more ambitious extension called EFL is under development.

From a theoretical viewpoint the key to all our work on software portability is a model of the computing environments in which our programs will be expected to operate. We assume a hardware-software environment that fully supports the PFORT language and is characterized by parameters (machine constants) in four basic areas: (1) logical unit numbers, (2) word size, (3) integer arithmetic, and (4) floating-point arithmetic. To demonstrate the use of this model, we discuss an algorithm by J. L. Blue for computing the Euclidean norm of a real vector. The algorithm is portable, accurate, and efficient, avoids overflow and underflow, and will be included in the next edition of PORT.

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Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • W. S. Brown
  • A. D. Hall

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