May 1972 Table of Contents | Communications of the ACM

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Home → Magazine Archive → May 1972 (Vol. 15, No. 5)

Table of Contents

ACM president's letter: unfinished business: III

Walter M. Carlson

Pages 299-300

An improved index sequential access method using hashed overflow

The Index Sequential Access Method (ISAM) is one of the most important file management systems used with moveable head disk devices. This study investigates the use of an unconventional method of treating overflow records. The …

James K. Mullin

Pages 301-307

The Multics virtual memory: concepts and design

As experience with use of on-line operating systems has grown, the need to share information among system users has become increasingly apparent. Many contemporary systems permit some degree of sharing. Usually, sharing is accomplished …

A. Bensoussan, C. T. Clingen, R. C. Daley

Pages 308-318

MUX, a simple approach to on-line computing

An on-line system operating as part of a normal batch system for the CDC 6600 computer is described. The system, which required one man-year for initial software implementation, although basically simple, provides the necessary …

Ronald D. Christman

Pages 319-329

A technique for software module specification with examples

This paper presents an approach to writing specifications for parts of software systems. The main goal is to provide specifications sufficiently precise and complete that other pieces of software can be written to interact with …

D. L. Parnas

Pages 330-336

Implementing Clenshaw-Curtis quadrature, I methodology and experience

Clenshaw-Curtis quadrature is a particularly important automatic quadrature scheme for a variety of reasons, especially the high accuracy obtained from relatively few integrand values. However, it has received little use because …

W. Morven Gentleman

Pages 337-342

Implementing Clenshaw-Curtis quadrature, II computing the cosine transformation

In a companion paper to this, “I Methodology and Experiences,” the automatic Clenshaw-Curtis quadrature scheme was described and how each quadrature formula used in the scheme requires a cosine transformation of the integrand …

W. Morven Gentleman

Pages 343-346

Fast finite-difference solution of biharmonic problems

Setting the Reynolds number equal to zero, in a method for solving the Navier-Stokes equations numerically, results in a fast numerical method for biharmonic problems. The equation is treated as a system of two second order equations …

D. Greenspan, D. Schultz

Pages 347-350

Minimax nonlinear approximation by approximation on subsets

A possible algorithm for minimax approximation on an infinite set X consists in choosing a sequence of finite point sets {Xk} which fill out X and taking a limit of minimax approximations on Xk as k → ∞. Such a procedure is considered …

C. B. Dunham

Page 351

The optimality of Winograd's formula

Richard Harter

Page 352

Algorithm 424: Clenshaw-Curtis quadrature [D1]

Clenshaw-Curtis quadrature is one of the most effective automatic quadrature schemes available, particularly for integrands with some continuous derivatives. It can also be used for any piecewise continuous integrand, although …

W. Morven Gentleman

Pages 353-355

Algorithm 425: generation of random correlated normal variables [G5]

We have programmed and made timing comparisons for two algorithms which sample the multivariate normal density N(&mgr;, V) = |V-1|/(2&pgr;)n/2·exp(- 1/2(Y - &mgr;)T V-1(Y - &mgr;)) (1) where V is an n X n covariance matrix, &mgr; is an n component …

Rex L. Hurst, Robert E. Knop

Pages 355-357

Merge sort algorithm [M1]

Sorting by means of a two-way merge has a reputation of requiring a clerically complicated and cumbersome program. This ALGOL 60 procedure demonstrates that, using recursion, an elegant and efficient algorithm can be designed …

C. Bron

Pages 357-358

Algorithm 427: Fourier cosine integral [D1]

Peter Linz

Pages 358-360

Algorithm 428: Hu-Tucker minimum redundancy alphabetic coding method [Z]

This algorithm implements the Hu-Tucker method of variable length, minimum redundancy alphabetic binary encoding [1]. The symbols of the alphabet are considered to be an ordered forest of n terminal nodes. Two nodes in an ordered …

J. M. Yohe

Pages 360-362

Curriculum recommendations for graduate professional programs in information systems

Pages 363-398

Page 404