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Communications of the ACM

Table of Contents


Ye indiscreet monitor


A procedure for converting logic table conditions into an efficient sequence of test instructions


A note on a set of test matrices for inversion


Note on stochastic matrices

A formula for numerical integration is prepared, which involves an exponential term. This formula is compared to two standard integration methods, and it is shown that for a large class of differential equations, the exponential …

Closing out a print tape

Some computer operating systems have a bad habit of inserting tape marks into the output stream willy-nilly. This often results in loss of output when a tape is scratched after its first file has been printed. Other operating …

Pei matrix eigenvectors

M. L. Pei [Comm. ACM 5, 10 (Oct. 1962)] gave an explicit inverse for a matrix of the form M + &dgr;I, where M is an n-square matrix of ones and &dgr; is a nonzero parameter. The eigenvalues of the Pei matrix were given by W. S. LaSor …

A semi-iterative process for evaluating arctangents

The technique of obtaining arctangents by inverse interpolation [1] is a relatively long process not suitable for a subroutine. The Taylor series expansion for arguments less than unity converges rather slowly for those near&pgr; …

Algorithm 203: STEEP1


Algorithm 202: generation of permutations in lexicographical order


Algorithm 206: ARCCOSIN


Algorithm 205: ATIVE


Algorithm 204: STEEP2


Algorithm 41, revision evaluation of determinant


Certification of algorithm 41: evaluation of determinant


Certification of algorithm 45: interest


Remark on algorithm 157: Fourier series approximation


Remark on algorithm 129 minifun : minifun


Certification of algorithm 158: exponentiation of series


Certification of algorithm 163: modified Hankel function


Certification of algorithm 167: calculation of confluent divided differences


Certification of algorithm 169: Newton interpolation with forward divided differences


Remark on algorithm 166: MonteCarlo inverse


Certification of algorithm 168: Newton interpolation with backward divided differences


Symmetric list processor

A list processing system in which each list cell contains both a forward and a backward link as well as a datum is described. This system is intended for imbedding in higher level languages capable of calling functions and subroutines …

MIRFAC: a compiler based on standard mathematical notation and plain English

A pilot version of the compiler MIRFAC, now in the operation, is described. The chief features of the system, which is intended for the solution of scientific problems, are the presentation of mathematical formulas entirely in …

A generalization of ALGOL


Computer-drawn flowcharts

To meet the need for improved documentation of written computer programs, a simple system for effective communication is presented, which has shown great promise. The programmer describes his program in a simple format, and the …

On the approximate solution of Δ u=F(u)

Three-dimensional Dirichlet problems for &Dgr;u = F(u), Fu ≧ 0, are treated numerically by an exceptionally fast, exceptionally accurate numerical method. Programming details, numerous examples and mathematical theory are supplied …

A general program for the analysis of square and rectanglar lattice designs

This paper describes a general-purpose program that will handle those incomplete block designs known as square and rectangular lattices. Flow diagrams are given so that the method of calculation may be programmed for any digital …

Group participation computer demonstration

Engelbart1 has reported on some demonstrations in which a group functions as various parts of a digital computer. These demonstrations are concerned with binary operations including addition. However, there are occasions when …

Letters to the editor: on word combinations


Letters to the editor: on the reference counter method