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Communications of the ACM

Table of Contents

Algorithm 221: Gamma functions

Algorithm 222: Incomplete beta functions ratios

Certification of algorithm 122: Tridiagonal matrix

Remark on algorithm 123

Certification of algorithm 150: SYMINV2

Certification of algorithm 197: Matrix division

A note on some compiling algorithms

Two compiling generators for arithmetic expressions are discussed: one presently in use in an experimental compiler, and an improvement suggested by K. Speierman of Burroughs.

Comments on “a continued operation notation”

This note is intended to clarify and correct several points in a recent paper describing some notations for symbol manipulation by M. P. Barnett [Comm. ACM 6(August, 1963)].

report on CCITT data communications study group meeting

Data communications was the subject of a two-week meeting held 24 September through 4 October 1963, in Geneva, Switzerland, by the International Telegraph and Telephone Consultative Committee (CCITT) Special Study Group A. Previous …

FORTRAN subroutines for time series data reduction

For several years the author has been concerned with time series data reduction of guided missile data derived from tracking, telemetry and static test instrumentation. The data, which is acquired from many sources and comes …

Polyphase sorting with overlapped rewind

A variation of the polyphase merge technique of sorting is described which permits one tape at a time to be rewound while the merge is continued on the remaining tapes. The result is the overlapping of a major portion of the  …

Tests on a computer method for constructing school timetables

A previously proposed computer method for constructing timetables, based on an iteration involving Boolean matrices, is described. In limited tests the method has successfully produced timetables on every trial. References are …

Randomized binary searching with tree structures

A more efficient method of using tree structures is proposed, which utilizes both plus and minus branches in the search path. Very significant gains result when the search key includes alphabetic characters.

The dangling “else”

Generating a canonical prefix encoding

Computer programs for generating a minimum-redundancy exhaustive prefix encoding are described. One program generates a Huffman frequency tree, another determines the structure functions of an encoding, and a third program assigns …

Computer-made perspective movies as a scientific and communication tool

It is easy to program the basic transformation required for a perspective drawing. This fact plus the advent of high speed microfilm printers such as the General Dynamics Electronics S-C 4020 makes possible perspective movies …

A technique for computer detection and correction of spelling errors

The method described assumes that a word which cannot be found in a dictionary has at most one error, which might be a wrong, missing or extra letter or a single transposition. The unidentified input word is compared to the dictionary …

A class of iterative techniques for the factorization of polynomials

A method of iteration is developed in terms of a function of somewhat arbitrary character. Sufficient conditions are given for convergence of the process, yielding factors of arbitrary degree for polynomials in one variable.  …

A Fourier series method for the numerical solution of a class of parabolic partial differential equations

A Fourier series method is described which, when applied to a certain class of parabolic partial differential equations, reduces the problem to a system of ordinary differential equations. An application is given for which the …

Conversion of a power to a series of Chebyshev polynomials

Even slowly convergent power series can be rearranged as series in Chebyshev polynomials if appropriate sequence transformations are used in evaluating the coefficients. The method is illustrated by computing the coefficients …

Digital data processor for tracking the partially illuminated moon

A study of lunar tracking techniques and fabrication of a breadboard to assess the feasibility of the best technique selected was conducted to define a tracking system for observation of the sightline to the center of a partially …

Some comments on the aims of MIRFAC