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Portability of Numerical Software

Volume 57 of the series Lecture Notes in Computer Science pp 158-164

# Fortran portability via models and tools

- W. S. Brown
- , A. D. Hall

## 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.

- Title
- Fortran portability via models and tools
- Book Title
- Portability of Numerical Software
- Book Subtitle
- Workshop, Oak Brook, Illinois, June 21–23, 1976
- Pages
- pp 158-164
- Copyright
- 1977
- DOI
- 10.1007/3-540-08446-0_41
- Print ISBN
- 978-3-540-08446-4
- Online ISBN
- 978-3-540-37071-0
- Series Title
- Lecture Notes in Computer Science
- Series Volume
- 57
- Series ISSN
- 0302-9743
- Publisher
- Springer Berlin Heidelberg
- Copyright Holder
- Springer-Verlag
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