Accession Number:

ADA055777

Title:

Software Tool(s) for Evaluating the Effects of Finite Wordlength.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s):

• Klein,Gary A.

Report Date:

1977-12-01

Pagination or Media Count:

185.0

Abstract:

In developing estimation and control systems, the algorithms developed are, in general, very sensitive to the wordlength of the onboard computer. Representation of the desired design can be greatly affected by the quantization resulting from truncation or round off. The result can be even more severe than numerical imprecision numerical instability can be generated that render algorithms totally useless. An important part of algorithm development is determining the appropriate wordlength. Proper wordlength can be determined by running the algorithm on a simulated n-bit machine for several values of n Results can then be evaluated against performance specification to determine the wordlength and precision requirements. The objective of this thesis was to process algorithms written in FORTRAN on the CDC 6600CYBER 74 computer systems such that the results obtained were similar to those obtainable on an n-bit machine. A preprocessor was designed which would modify the algorithms code so that the numerical effects of n-bit wordlength could be realized. An n-bit simulation tool was successfully developed and implemented at the FORTRAN level.

Descriptors:

• *ALGORITHMS
• SIMULATION
• CONTROL SYSTEMS
• ACCURACY
• COMPUTER ARCHITECTURE
• THESES
• FORTRAN
• LENGTH
• PRECISION
• USER NEEDS
• PREPROCESSING
• MINICOMPUTERS
• ARITHMETIC UNITS
• WORD ORGANIZED STORAGE

Subject Categories:

• Computer Programming and Software
• Computer Hardware

Distribution Statement:

APPROVED FOR PUBLIC RELEASE