Decision tables in Algol 60

This paper defines an extension to Algol 60, which allows the programmer to write decision tables in his Algol program. A pre-processor converts the decision tables to Algol, and its output is used as input to the ordinary Algol compiler. The generated Algol program uses a straight-forward and efficient algorithm for choosing the appropriate decision rule.     

Features of the gier algol 4 system

A brief survey is given of the new features included in the Gier Algol 4 compiler system, as compared with its predecessors. As background the more recent additions to the hardware of the machine are described. The new features primarily aim at a more effective use of the existing machine facilities, including optional facilities existing only in some installations.     

A Cosmo-simula program for a simple air-pollution model

With a programmed example, the article introduces Cosmo-Simula, a language designed for the programming of continuous simulation. The language uses the Algol part of Simula for the programming of the algorithmic part and an extension of Cosmo for the programming of the administrative part of the problem. The translator is programmed using the Algol part of Simula and makes the extended Cosmo available for computers with an Algol-compiler.     

Part-compilation in high-level languages

Many programming languages include the ability to divide large programs into smaller segments, which are compiled separately. When a small modification is made to a large program, then the affected segment only has to be re-compiled.This paper discusses how high-level languages like Algol 68, Algol W or Simula 67 can incorporate part-compilation in a usable, secure and efficient way.     

Implementation of a low round-off summation method

The method of Linz [1] for accurate floating-point summation has been programmed in Algol 60. The accuracy obtained confirms the analysis given by Linz. However, similar accuracy may be obtained with the use of quasi-double-precision [2].     

Intrinsic Compiler Support for Interval Arithmetic

Interval arithmetic provides an efficient method for monitoring errors in numerical computations and for solving problems that cannot be efficiently solved with floating-point arithmetic. To support interval arithmetic, several software tools have been developed including interval arithmetic libraries, extended scientific programming languages, and interval-enhanced compilers. The main disadvantage of these software tools is their speed, since interval operations are implemented using function calls. In this paper, compiler support for interval arithmetic is investigated. In particular, the performance benefits of having the compiler inline interval operations to eliminate function call overhead is researched. Interval operations are inlined with the GNU gcc compiler and the performance of interval arithmetic is evaluated on a superscalar architecture. To implement interval operations with compiler support, the compiler produces sequences of instructions that use existing floating point hardware. Simulation results show that the compiler implementation of interval arithmetic is approximately 4 to 5 times faster than a functionally equivalent interval arithmetic software implementation with function call overhead and approximately 1.2 to 1.5 times slower than a dedicated interval arithmetic hardware implementation.     

The spline curve,a smooth interpolating function used in numerical design of ship-lines

It has been found that a numerical approximation of a ship-designer's spline results in a smooth interpolating function. An algorithm which computes the function coefficients is presented in Algol. Methods to vary the stiffnes of the spline are included. A test of fairness is described and finally a more elaborate algorithm which leads to a closer approximation is outlined.     

An algorithm for determining the automorphism partitioning of an undirected graph

An Algol 60 program for determining the automorphism partitioning of an undirected unlabelled graph is presented. For graphs that do not contain strongly regular subgraphs, the time is at worstO(n ⁴) wheren is the number of vertices in the graph. The algorithm is based on the Corneil-Gotlieb conjecture.     

On Nielsen's generalized polylogarithms and their numerical calculation

The generalized polylogarithms of Nielsen are studied, in particular their functional relations. New integral expressions are obtained, and relations for function values of particular arguments are given. An Algol procedure for calculating 10 functions of lowest order is presented. The numerical values of the Chebyshev coefficients used in this procedure are tabulated. A table of the real zeros of these functions is also given.Shortened version of CERN preprint DD/CO/69/5.Supported by Swiss National Research Fund. On leave from Consejo Nacional de Investigaciones de la Republica Argentina.     

A universal compiler system based on production rules

This paper describes a compiler system which makes use of production rules for the translation. The source language syntax is defined in terms of a phrase structure grammar. Semantic rules are provided by an extension of the production rules, and special symbols are introduced for this purpose. Recognition of symbol strings is facilitated by a special syntactic filter routine. An example of a simple macro compiler is given to illustrate the basic concepts of the system.     

关于一类具有大范围收敛性的迭代法

本文由Hadamard因子分解定理出发,证明了推广的Laguerre迭代方法对求解一类超越方程具有大范围收敛性.对复根允许存在的区域作了讨论.得出了Riemann假定成立的一个必要条件.还给出了此迭代法的Algol 60程序.     

A basic course on compiler principles

An attempt to devise a methodology of compiler design is described, and an outline is given for a possible course on this subject. The theoretical basis is formed by the concepts of phrase-structure language, finite-state- and stack-acceptor, and transducer. As their extension capable of processing context-dependent elements of languages, a so-called Table-Transducer is postulated, and it serves as the core-algorithm upon which compilers are based. The developed theory and method of compiler construction is applied to an example of a simple programming language.     

The differentiation-enabled NAGWare Fortran compiler

We present a research prototype of the differentiation-enabled NAGWare Fortran compiler. The compiler provides built-in automatic differentiation capabilities for the generation of code for computing first and second derivatives of numerical simulation codes written in Fortran. Tangent-linear, adjoint, and second-order adjoint code is obtained by a semantic transformation of the compiler's intermediate representation. Three successful reference applications are discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solving the eigenvalue problem for matrices

One presents some algorithms related among themselves for solving the partial and the complete eigenvalue problem for an arbitrary matrix. Algorithm 1 allows us to construct the invariant subspaces and to obtain with their aid a matrix whose eigenvalues coincide with the eigenvalues of the initial matrix and belong to a given semiplane. Algorithm 2 solves the same problem for a given strip. The algorithms 3 and 4 reduces the complete eigenvalue problem of an arbitrary matrix to some problem for a quasitriangular matrix whose diagonal blocks have eigenvalues with identical real parts. Algorithm 4 finds also the unitary matrix which realizes this transformation. One gives Algol programs which realize the algorithms 1–3 for real matrices and testing examples.