bluuebunny/crossref_metadata_2025 huggingface dataset:
Human diversity and the choice of interface
Authors: Hiltz Starr Roxanne , Turoff Murray
Published: April 2007

As part of a field trial, the Electronic Information Exchange System (EIES) provided a variety of interfaces and user aids. Users were permitted to freely choose from the available variety at any time. They were then asked to report on their frequency of use of the various alternatives at two points in time. We found that there is no one style of interface or source of user support which will satisfy all users at any point in time, or even the same user as experience and familiarity with the system change. While their generalizability is unknown, our observations suggest that human helpers (user consultants on EIES) are the single most valued source of user support, and that system designers should consider incorporating an integrated and somewhat redundant system of both menus and commands into the interface.
Living taxonomies in the corporate world
Authors: Loebner Egon E. , Gadol Steven D.
Published: April 2007

The complexity of information processing, disseminating and controlling is very high within a sizable corporation. Database design, targeted to carry out these functions, is constantly improving. Nevertheless, nonprogrammers have trouble accessing most databases. Layers of EDP personnel, as well as unresponsive and cumbersome systems, are an obstacle to effective database use.In this paper, we describe an exploratory investigation of databases based on REL ENGLISH [1]. In our system, data structures and access language were designed to map closely the corporate structure and its terminology. Our test vehicle was a portion of Hewlett-Packard's internal information network, the corporate Order Processing System. We have identified about a dozen job related perspectives belonging to geographically dispersed and functionally stratified end-users within various entities of the HP organization. A multinested data model is an intertwined hierarchy: the join of separate hierarchies with different lexicons but shared data events. For our test, we have selected two major intersecting multinested user views: sales and manufacturing. Our design accommodates users with differing perspectives of this model.The system data structures were constructed using the REL ENGLISH primitives. The Condensed Order Records (COR) base spanned a multinested hierarchy four levels deep for the Sales Organization taxonomy and five levels deep for the Manufactured Products taxomony. The design permits the user to query the COR base about the data model itself. He can, of course, also obtain the standard statistical views of the data.Corporate taxonomies are dynamically changing structures. The database model needs to reflect this change. In most cases, the user wants to manipulate data at three levels in his own job taxonomy and at all levels in the other taxonomies. The multinested data model is needed in order to permit the user to view the data from the same perspective that he views his job in the corporate organization.
The graphic design of friendly faces for information management (abstract only)
Authors: Marcus Aaron
Published: April 2007

Principles of graphic design have been utilized in redesigning the interface for Seedis, a large information management system. The structure and processes of Seedis are briefly described. The graphic design approach is explained and graphic design principles are outlined. Examples of enhanced menus, prompts, help messages and data directories are shown to indicate the nature of improvements.
Design issues for online documentation systems (abstract only)
Authors: Steinhaus Carolyn P.
Published: April 2007

The design of an effective interactive documentation system is introduced by tracing a hypothetical development effort aimed at shifting information contained in printed volumes of documentation to a form suitable for interactive access. Taking this approach presents a view of online documentation systems as the result of the process of adapting information conveyed in printed volumes to the constraint of interactive software considered as an information medium. The resulting discussion necessarily involves consideration of the demands which interactive software makes on both the organization of information about interactive programs and on the cognitive capacities of people using it.Existing documentation is typically intended to serve all of the informational needs of any person who uses an interactive software system. The requirements of software systems for structure and precision demand a more detailed understanding than currently exists of exactly how to provide information to people of varying levels of experience with a particular program or with computing in general. The interaction between the purposes of existing documentation and the requirements of an online system provide an interesting context for discussion of the major issues facing the designer of an interactive documentation system.
Case study of a user-oriented conferencing system (abstract only)
Authors: Zinn Karl L.
Published: April 2007

This session described how CONFER, a computer-based conferencing system at the University of Michigan, was developed with participation of users, and what impact the system has on communities of users. At this conference it may be especially interesting to discuss various ways in which help provided to new users has evolved. Some extrapolations may be made for other than electronic communication aids: orientation and training, on-line reference information, on-line consultation, etc.
Uses of CONFER at Wayne State University (abstract only)
Authors: McCord Alan
Published: April 2007

CONFER is used by a variety of organizations which have no
direct contact with any MTS site (the CONFER host computer system).
In many cases, the main contact of the CONFER user is with the
third party vendor or consultant who is supporting the networking
effort. Several problems arise when the third party relationship is
not broadened to include the institutional consulting and
documentation efforts. Such problems include:1. Overload on the
time of the third-party consultant.2. Production of custom
documentation which parallels the institutional documentation.3.
User perceptions that they are not "ready" for institutional
documentation.4. Development of abbreviated cognitive maps of the
system and its user network.5. Users exchange superstitious views
of how the system works.While it is not yet clear that the
absorption of third-party, mediated networks will solve such
problems, it is an obvious first step to a solution.

MTS Help Facility

A version of CONFER is tentatively planned for use as the
principal Help Facility at WSU. A subset of CONFER capabilities
will be employed to decrease demands on the system.

Features of the Help Facility will include agenda string
searches, execution of computer assisted instruction lessons from
within tbe CONFERence, a "suggestion box" facility, and user
modelling features intended to decrease user frustration and
maximize efficiency. Existing help files will be called from the
Help Facility to increase the redundancy of available help to the
user.

The agenda used will be multi-dimensional, allowing the user to
search for help within subject areas, type of information and skill
level. For example, the user would be able to view all items which
serve as tutorials on statistical packages with the CONFER command:
AGENDA TUTORIALS+STATISTICS. Similarly, the user will be able to
search item descriptors or text for character strings, such as
using WHICH "SPSS" to locate all items dealing with SPSS.

Requests for help will be sent directly to various CSC
departments, and responded to either via CONFER or telephone. User
suggestions and requests will be screened on a continuing basis by
CSC staff, and changes to the information contained in each item
will be made as a result of these suggestions. Materials developed
by users will be solicited for inclusion in the Help Facility.
Repeated additions
Authors: Hansen Eldon
Published: April 2007

The recent note by Morris [1] prompts me to describe the following process for doing repreated floating point additions. It seems certain that the process is not new; but I have not seen it described elsewhere. It has perhaps been ignored because of its limited practical value. However, it serves as an interesting example for the classroom.
The explicit factorization of two commonly occuring matrices
Authors: Kershaw D.
Published: April 2007

Tridiagonal and periodic tridiagonal matrices often occur in numerical analysis and frequently in examination questions. Two such matrices are presented here together with their LU factorizations. The constructive proofs of the results are tedious but verification is straightforward.
Toward a definition of the term numerical mathematician
Authors: Fritsch F. N.
Published: April 2007

In attempting to evaluate the responses to the SIGNUM 1971 Nonacademic Numerical Mathematics Survey (see summary report published elsewhere in this Newsletter), it became clear that there is a need for a definition of the term "numerical mathematician". Without such a definition, the results of any such survey are necessarily ambigous. For example, our Laboratory employs over one hundred computer programmers, who frequently use mathematical subroutines in their codes. Are they numerical mathematicians? Furthermore, another hundred or more physicists and engineers are regular users of numerical methods. Should they be called numerical mathematicians?
Applications oriented algorithms
Authors: Gupta K. K.
Published: April 2007

Numerical analysis has become an integral part of practical engineering problem analysis. Thus current structural analysis techniques essentially consist of two distinct numerical procedures. Firstly the continuum is discretized by the finite element method, a variant of the well-known Ritz's process, yielding sets of simultaneous algebraic equations for equilibrium and eigenvalue problems or sets of simultaneous ordinary differential equations for the propagation problems. Second such equations are next solved by relevant numerical techniques.
On step control criteria
Authors: Butcher J. C.
Published: April 2007

Programs for the numerical solution of ordinary differential equations generally use one of two alternative criteria for step size control, these are, the error per step criterion and the error per unit step criterion. The purpose of this note is to present a trivial example which illustrates an argument favouring the error per unit step criterion.
Profile on the numerical mathematics section of the Lawrence Livermore laboratory
Authors: Fritsch Fred N.
Published: April 2007

The following information is presented in response to the Newsletter Editor's request for "profiles of individual Numerical Mathematics Groups in industry."
Would you believe structured Fortran?
Authors: Hull T. E.
Published: April 2007

Structured programming [1] is a common topic of conversation these days. It appears to be an idea that has finally arrived, and it is "in" to teach about structured programming, even if we don't quite understand exactly what is meant by it.
A modified hotelling deflation scheme for inverting matrices
Authors: Gangi Anthony F. , Shapiro James N.
Published: April 2007

The Hotelling Deflation Algorithm can be modified to generate, with almost no additional effort, the inverse of a matrix simultaneously as its eigenvectors and eigenvalues are being determined. The method is particularly appropriate for small computers (or programmable calculators) with limited memory because the modified matrix occupies the same memory space used for the original matrix.
A memory of George Forsythe
Authors: Moler Cleve
Published: April 2007

Early last March, I was in California and so dropped by to visit George Forsythe. I recall our conversation because it included a few of the many things George was interested in. We talked about the NATS project work in subroutine testing and distribution. He described a textbook he was writing. He went over plans for his upcoming sabbatical leave, recalling Ed Feigenbaum's remark that the only trouble with being on the Stanford faculty was that you couldn't go to Stanford for your sabbatical. He said that he had decided to accept another term as chairman of Stanford's Computer Science Department. He mentioned a study he had just made for the chancellor of another university, assessing their program in computer science. We discussed the progress which two of the grad students were making on their theses. And we even talked a little numerical analysis -- he told me about a coordinate-independent theory of splines.
Fast eigenvalue calculations on the CDC 6000-7000 computers
Authors: Nikolai Paul J.
Published: April 2007

For computing a relatively small sample of the eigenvalues of an hermitian matrix, the bisection method is justifiably popular. The procedure has been widely implemented in many programming languages for a great number of machines. In this note we show how to implement the Sturm sequence procedure, the heart of the bisection method, in ANSI FORTRAN which on a computer with a highly parallel central processing unit can yield major savings in execution time. We illustrate using FORTRAN Extended, Optimization Level 2, for the CDC 6600 for which the method is especially appropriate.
A simple example of an ill-conditioned matrix
Authors: Tee Garry J.
Published: April 2007

The following example has been found useful in courses of Numerical Analysis, for illustrating the concept of ill-conditioning.
Some numerical experiments with DIFSUB
Authors: Shampine L. F. , Gordon M. K.
Published: April 2007

One of the best general purpose differential equation solvers is Gear's variable order, variable step Adams code DIFSUB [1]. (It is combined with methods for the solution of stiff problems but we are only concerned with the Adams methods here.) We have done extensive numerical testing of the code, which complement the excellent comparative tests of Hull and his co-workers [2], in order to understand its design and performance. We shall report some of our observations in the hope that others will find them useful.
Errata
Authors: Farkas Imre
Published: April 2007

The fifth paragraph of the paper, "A Conjecture in Numerical Linear Algebra", SIGNUM Newsletter, Vol. 9, No. 4, p 10-11, was erroneous.
Mathematical software patterns
Authors: Battiste E. L.
Published: April 2007

The past and current situation in the production of mathematical software requires that, in order to project the future, one realize the critical elements in such production. These are discussed below, with projections, under the topics Origins, Support, and Requirements.
On structured programming in FORTRAN
Authors: Charmonman S. , Wagener J. L.
Published: April 2007

A modification is suggested to improve Hull's format of structured programming in FORTRAN. In addition a FORTRAN versions of Dijkstra's IF-FI and DO-OD constructs is presented, with examples of program segments written in this form.
Typical problems for stiff differential equations
Authors: Gordon M. K. , Shampine L. F.
Published: April 2007

The solution of stiff differential equations has become a very active area in recent years. To have some idea as to the wishes of practitioners would be of obvious value to researchers developing new tools, to software designers producing new codes, and to those evaluating the codes available at present. Because there is surprisingly little quantitative information published about the characteristics of the problems being solved, we have conducted a survey at the Sandia Laboratory in Albuquerque. This is a non-profit research and development firm contracted to the AEC (now ERDA) which does a variety of scientific computing. The size of the computing effort is suggested by the number of employees with Ph.D.'s, about 500, and the array of computers, three CDC 6600's, a UNIVAC 1108, a PDP-10, an IBM 7090, and some smaller machines. While our interviews can be no more than indicative, we hope others will also find this brief summary useful.
Recent developments in numerical techniques for treating material interfaces (abstract)
Authors: Ruppel Hans M.
Published: April 2007

The Arbitrary-Lagrangian Eulerian Technique (ALE)
1
provides a framework in which one can regrid individually different regions of a calculational mesh. In particular, one can treat an interface between materials as a Lagrangian line and rezone the remaining parts of the grid with some appropriate algorithm. This keeps material from being fluxed across the interface and avoids the problem of mixed cells with the attendant difficulty of obtaining pressures for such cells. At the same time it maintains some degree of regularity in the regions away from the interface.
AFWL hydrocode development parallel techniques
Authors: Needham Charles E. , Durrett Richard E. , Matuska Daniel A.
Published: April 2007

The methods employed in solving the fluid dynamic equations are especially amenable to parallel techniques. In fact, one of the major forces behind the development of ILLIAC IV was the solution of hydrodynamic problems. During the early phases of ILLIAC IV development, (mid 1970 to 1971), the Air Force Weapons Lab expended several manyears of effort in converting its hydrocodes to the ILLIAC IV architecture. This has been reported in AFWLTR 72-33 "Shell for the ILLIAC IV". The experience has carried over into the codes presently used at AFWL which have many characteristics necessary for parallel processing. Applications of the parallel philosophy to serial machines has decreased running times by a factor of 2 or more. Our original single material hydrocode ran at the rate of approximately 1.5ms/zone/cycle on the CDC6600. The present version runs at about 0.5ms/zone/cycle.
DCG
Authors: Engquist Björn , Smedsaas Tom
Published: April 2007

DCG is a program which generates FORTRAN code for difference approximations from a mathematical specification of a hyperbolic system.
Application of finite element methods to solving immiscible displacement problems with sharp fronts (abstract)
Authors: Price Harvey S.
Published: April 2007

Many reservoir engineering problems involve solving fluid flow equations, whose solutions are characterized by sharp fronts and low dispersion levels. This is particularly important in tracking small slugs which are characteristic of chemical floods, polymer floods, first and multiple contact hydrocarbon miscible displacements and most thermal processes. The use of finite difference approximations to solve these problems when low dispersion levels and small slugs need to be accurately modeled is prohibitively expensive. In two dimensions, as many as 500 grid blocks on a side would be required in order to obtain the necessary accuracy. However, the use of high order finite element schemes are shown to be a very effective means of economically solving this problem. This paper presents some numerical results of a research project recently completed which has demonstrated that high order finite element methods can be used to solve difficult reservoir engineering problems where finite difference approximations would be prohibitively expensive.
The QMESH mesh generation package (abstract)
Authors: Jones Rondall E.
Published: April 2007

A package of five programs centering around the highly flexible, powerful, two-dimensional mesh generation program, QMESH, is presented. Together, the five programs provide a tool for generation, bandwidth minimization and display of meshes with Q4 or Q8 elements. The package's primary purpose is generation of input for finite element analysis programs.
Finite element mesh generation for planar and shell type structures (abstract)
Authors: Cavendish James C. , Wixom James A.
Published: April 2007

In many cases, the overriding difficulty associated with finite element analyses of complex structures is the generation of error-free finite element meshes. In view of this situation, a number of mesh generation schemes for planar (e.g., [1], [2]) and shell (e.g., [3], [4]) structures have recently been proposed (see [5] for an extensive bibliography). At one extreme are the fully automatic methods in which the computer is used to determine regions of high and low element densities and then create a finite element mesh accordingly. At the other extreme are methods which require the analyst to completely define the element mesh, while the mesh generating algorithm itself performs only minor clerical tasks such as checking for consistency and error detection. While the fully automatic methods tend to be somewhat inflexible and frequently time consuming to implement, the simplest schemes fail to relieve the user of enough of the tedium accompanying manual decomposition of the structure. We feel that the two semi-automatic mesh generation approaches described in this paper offer a good compromise between the two extremes in mesh generation:(i) A semi-automatic mesh generation algorithm capable of generating meshes of triangular elements for the decomposition of any multiply connected, polygonal, planar region. Once the user has described the boundary of the region and supplied any necessary element density input information, the algorithm automatically positions nodes within the region and assembles triangular elements from these nodes.(ii) An interactive method which permits finite element modeling of three-dimenslonal shell structures on a graphic console. The salient features of this approach involve mathematical surfacing techniques which allow a shell to be represented as a mathematically deformed rectangular domain.
Factors limiting academic participation in the development of large mathematical software packages
Authors: Kelman Robert B.
Published: April 2007

The December 1975 SIGNUM meeting of Software for Partial Differential Equations seemed to formalize a trend which over the past few years has become ever more evident. Namely, the the development of medium and large scale software packages, say anything more than five hundred statements, is a project which can no longer be carried out in a university. Such projects are now almost wholly within the province of industrial and governmental laboratories. As can be seen from the program of the meeting (ACM SIGNUM Newsletter 10, 1975; No. 4, pp. 2-3), only two our of seventeen papers came from universities and one of these two papers concerned itself with a modest size algorithm for solving systems of linear algebraic equations. The reasons for this state of affairs are not hard to find. It is expensive to develop such software, and it is not altogether appropriate in a university to tie up manpower and money in such extensive undertakings. After all, departments of mechanical engineering do not build boilers, or perhaps, since new program development involves much innovation, a more accurate analogy would be to say that departments of aeronautical engineering do not build new jetliners. Also, because of tight money and excess personnel, pressures on faculty to "Produce" have increased and producing means publishing.
Background of users of scientific computing
Authors: Dunham Charles B.
Published: April 2007

In writing and documenting mathematical software, it is essential to have an idea what the average user, consultant, or program librarian knows. The author, therefore, did a survey, based mainly on his own university, of what background these people had. The results suggest that no knowledge of scientific computing, apart from a language, can be assumed.
A unified decimal floating-point architecture for the support of high-level languages
Authors: Ris Frederic N.
Published: April 2007

This paper summarizes a proposal for a decimal floating-point arithmetic interface for the support of high-level languages, consisting both of the arithmetic operations observed by application programs and facilities to produce sub-routine libraries accessible from these programs. What is not included here are the detailed motivations, examinations of alternatives, and implementation considerations which will appear in the full work.
A note on variable order strategies for differential equation solvers
Authors: Warner D. D.
Published: April 2007

In the design of a step-size and order monitor for the numerical solution of ordinary differential equations, the conventional wisdom holds that the monitor should start with a cautious first-order method. For example, Gear [1], Hindmarsh [2], Schryer [3], and Shampine and Gordon [4] require that the initial successful integration be accomplished with a first-order method. Of course these authors have other good reasons for their design besides mere caution. However, for stiff ODE's we will show that this restriction can lead the monitor to abandon perfectly reasonable problems.
Step control criteria for stiff equations
Authors: Ehle Byron L.
Published: April 2007

In a recent note [1], J. C. Butcher showed using a simple 2 stage first order Runge-Kutta method that an error per unit step criterion gave consistent results on a nonstiff problem while an error per step criterion did not. This note considers the effect of employing error per unit step when stiff equations are involved.
Review of "Complexity of Sequential and Parallel Numerical Algorithms by J. F. Traub"
Authors: Horowitz Ellis
Published: April 2007

The following table of contents perhaps best describes this book which includes texts of invited papers given at a Symposium at Carnegie-Mellon on May 16-18, 1973.
Proposed standard subprograms for basic linear algebraic operations
Authors: Lawson C. L.
Published: April 2007

In the SIGNUM Newsletter, Vol. 8, No. 4, October 1973, page 16, Hanson, Krogh and Lawson presented the thesis that certain advantages would accrue to the scientific computing community if general agreement could be reached on the specifications of a set of FORTRAN callable subprograms for basic linear algebraic operations such as the dot product, y : = αx + y, etc. It was also proposed that constructive discussion of this idea would be furthered by having definite specifications to consider. Specific proposals for subprogram names, parameter lists, and functional specifications were given for a set of thirty-nine such subprograms in the Jet Propulsion Laboratory report JPL TM 33-660 of November 15, 1973.
Note on the startup of ODE solvers
Authors: Hindmarsh A. C.
Published: April 2007

In a recent note in this Newsletter [1], Warner concludes that stiff ODE solvers may need to start up with a high-order method because a first-order startup can lead to certain incompatible requirements if the problem is sufficiently stiff. This note attempts to show why that conclusion is unwarranted.
Publication of numerical algorithms
Authors: Dunham Charles B.
Published: April 2007

Several journals exist which publish numerical "algorithms" in the form of a mixture of natural language and mathematics. Very often a pre-condition for publication is a convergence proof. Some of these journals also publish comparison of algorithms via numerical experiments. This is all very fine, but is it of much use to users of algorithms?
TIPS for organizing a local ACM-SIGNUM group
Authors: Hanson Richard J.
Published: April 2007

Have you ever wanted to regularly meet with people having interests in numerical analysis? Perhaps forming a local ACM-SIGNUM group is the answer. What needs to be done to start such a group? This question often stymies people and kills the whole idea. Some of the major points that must be considered are these.
An adaptive extrapolation algorithm for automatic integration
Authors: de Doncker Elise
Published: April 2007

An algorithm for automatic integration has been developed, which is globally adaptive and makes use of a non-linear extrapolation technique. It allows jump discontinuities and singularities of several types to be integrated automatically in an accurate and efficient way.It will be outlined with regard to both its theoretical background and its application for general-purpose integration over finite and infinite ranges.
ROSEPACK-robust statistics estimation package
Authors: Klema Virginia
Published: April 2007

ROSEPACK (RObust Statistics Estimation PACKage) is a system of Fortran subroutines and an interactive driver to compute solutions to the iteratively reweighted least square problem. The weights are determined from the data and the linear fit and are computed as functions of the scaled residuals.
Principles and preferences for computer arithmetic
Authors: Reinsch Christian H.
Published: April 2007

This working paper arose out of discussions on desirable hardware features for numerical calculation in the IFIP Working Group 2.5 on Numerical Software. It reflects the views of all members of the group, although no formal vote of approval has been taken; it is not an official IFIP document. Many people contributed ideas to this paper, especially T. J. Dekker, C. W. Gear, T. E. Hull, J. R. Rice, and J. L. Schonfeldor.
A comparison of two recent approaches to machine parameterization for mathematical software
Authors: Smith Brian T.
Published: April 2007

Recently, there have been published two different proposals for expressing the dependence of numerical software on the environment. One proposal, which is essentially described in two papers [1,2]** characterizes the dependence of the software on the machine architecture essentially in terms of the representation of floating point entities in the machine. The second, more recent proposal, described in [3] characterizes the dependence of the software on the environment in terms of models both the floating point numbers and of the behavior of the arithmetic unit of the machine.

The purpose of this paper is to expose and clarify the differences and similarities between these two approaches. It is the author's opinion that the two approaches interpreted in their strictest sense serve two distinct purposes. When each is interpreted imprecisely, their roles overlap.

In order that the comparisons briefly discussed below are fully understood, we need to briefly summarize the separate approaches. Since our interest here is in the parameterization of the numerical aspects of the environment, the non-numerical parameters discussed in [1] and the considerations of implementation discussed in [2,3] will not be considered here.
A transportable system for management and exchange of programs and other text
Authors: Snyder W. V.
Published: April 2007

Computer software is usually exchanged between different computer facilities via punched cards or magnetic tape. For up to about 1000 images, cards are cheaper and probably easier to deal with than tape. The primary problem with cards is the variety of punch codes. Frequently, one also has the minor nuisance of repunching cards damaged in transit. For larger amounts of data, tape is cheaper, but there are so many tape formats in use that the recipient frequently has trouble reading a tape, even if the format is simple and well defined. Occasionally, one has the problem of parity errors, which make a tape essentially worthless. When test data, modules in several languages, computer output or documentation are included, the lack of organization in the material can cause a substantial amount of unnecessary human labor.

This paper presents a system for exchanging information on tape, that allows information about the data to be included with the data. The system is designed for portability, but requires a few simple machine dependent modules. These modules are available for a variety of machines, and a bootstrapping procedure is provided. The system allows content selected reading of the tape, and a simple text editing facility is provided. Although the system recognizes 30 commands, information may be extracted from the tape by using as few as three commands. In addition to its use for information exchange, we expect the system to find use in maintaining large libraries of text.
A comparison of optimal scaling and preconditioning
Authors: Evans D. J. , Hatzopoulos M.
Published: April 2007

In this paper we shall compare two methods proposed for the equilibration of ill-conditioned linear systems when the coefficient matrix is small, dense and positive definite. Many workers have discussed ways of overcoming the problem of ill-conditioning and the main theme of all the methods is to transform the given system to one where the coefficient matrix is better conditioned.
Error-free computation with finite number systems
Authors: Gregory Robert Todd
Published: April 2007

Since an automatic digital computer is a finite machine, it is capable of representing, internally, only a finite set of numbers. Thus, any attempt to use an automatic digital computer to do arithmetic in the field of real numbers (R, +, ·) is doomed to failure because R is an infinite set and most of the elements in R cannot be represented.
Numerical computations
Authors: Rice J. R. , Gear C. W. , Ortega J. , Parlett B. , Schultz M. , Shampine L. F. , Wolfe P. , Traub J. F.
Published: April 2007

This report on research in numerical computation is part of the Computer Science and Engineering Research Study (COSERS) which is aimed at technically educated people outside the Computer Science field. This goal led the panel to face many difficult choices between precise, but excessively technical, descriptions and looser, but more accessible expositions. The panel hopes that all readers will keep this in mind.
The impact of the proposed standard for floating point arithmetic on languages and systems
Authors: Feldman Stuart I.
Published: April 2007

Most programming languages seem to take a grudging approach to floating point computation. Many processors support these operations, and some peculiar and important users insist on using them, so languages provide some facility for using floating point entities. But very little care seems to be taken with numeric issues. Part of the problem is the wide range of anomalous hardware that must be made to "fit" the language. A language definition can be very vague (the most popular approach), or it can cover the limitations and anomalies by a careful specification (as in Brown's model [1]), or it can restrict its domain to particular hardware (such as the Floating Point Standard). The main impact of the proposed floating point standards may be to force a reconsideration of the role of floating point in programming languages. The following comments apply to all of the major proposals; where details are needed for a specific example, the Kahan, Coonen, and Stone [2] proposal is used.
Complex double precision in association with Fortran 77
Authors: Reid John
Published: April 2007

Many scientific and engineering calculations require the use of complex double precision arithmetic and therefore Fortran 77 compilers are likely to include extensions to provide it. This note suggests a precise form for such an extension in the hope that its wide use will aid portability. It has been discussed by IFIP WG 2.5 on Numerical Software and has been approved by the working group, but does not constitute an official IFIP document.
Numerical methods, large codes, and programmers
Authors: Saylor Paul E.
Published: April 2007

I asked Johnson if solving linear equations was a big part of the computational load at the laboratory. He said it must be about seventy-five percent of the machine time, but that his work to try to improve linear equation routines was mostly ineffectual. "You would go into the code and think you had it running faster, then they'd change the geometry or coefficients and that'd just kill you. You tamper with that code and then it might run a hundred hours of 7600 time over the weekend and not be worth a damn. It'd come back and be nothing but spaghetti. You get burned a few times like that and you think twice about changing anything. But like I say, if you could figure out a way to do it better it sure would make a difference. Only I never could."
Software basics for computational mathematics
Authors: Cody W. J.
Published: April 2007

This article discusses problems at the software design and implementation level that transcend any particular subfield of computational mathematics, but which are important to all subfields. The discussion includes desirable attributes of numerical software that are independent of the underlying algorithms, ways in which software with these attributes exploit arithmetic characteristics of the host computer, advantages to the gathering of numerical software into thematic packages and the problems involved in such work, and challenges in testing numerical software. A nontechnical overview of the subject is followed by a technical discussion which includes suggestions for research activities within DOE.
Microprogrammed interval arithmetic
Authors: Moore R. E.
Published: April 2007

Computational methods using interval arithmetic allow the computer to provide rigorous error bounds along with approximate solutions for a wide and growing class of computational problems. A recent survey [1] lists over 700 references. The implementation of interval arithmetic using subroutine calls is inefficient - typically 10 to 100 times slower than floating-point arithmetic [2]. By microprogramming interval arithmetic, we can reduce this factor to around 2. This can be done by a user who has a machine with a writable control store or, better still, by a manufacturer into the read-only control store.
An implicit matrix inversion process
Authors: Evans D. J.
Published: April 2007

An implicit iterative method for improving the accuracy of the inverse matrix is presented and shown to possess superior convergence properties over the well known quadratically convergent Hotelling method. Numerical examples are included to illustrate the new method. It is proposed that the new techniques may be useful in statistical analyses where matrix inverses are required.
Matrix calculations on hand-held calculators
Authors: Stewart G. W.
Published: April 2007

Recently there have appeared three hand-held calculators of such large capacity that they might well be called computers. They are the Texas Instruments TI-59, the Hewlit-Packard HP-41C and the Radie Shack TRS-80PC. These computers are characterized by a comparatively large memory which can be variably partitioned into an instruction bank and a data bank. In all three computers the memory is large enough to accommodate a Gaussian elimination program and at least an 8x8 matrix. Thus it is possible to develop serious matrix software for these computers. In this article I would like to describe some of the things I have learned from my own endeavors along this line.
Function minimization on special computers
Authors: Nash J. C.
Published: April 2007

Rather than presenting new material, this paper is very much a reassessment of old ideas in the context of new needs or possibilities. Much of what is included lies in the realm of opinion, hopefully well-informed opinion. However, the practice of function minimization -- now becoming a mature science on large, general purpose computers -- remains a sort of witchcraft on special computers.
Scientific computations using micro-computers
Authors: Battiste E. L.
Published: April 2007

We review software and hardware of micro-computers in the light of requirements for the production of robust software. We consider that attitudes about such production on large scale computers which have been developed over the last fifteen years should be adhered to, and that user protection from inadequate software is most important. The typical computer user will tend more and more to consider computational ingredients made available to him to be "black boxes", and will be prone to rely on results in the same manner as he relies on arithmetic componentry to perform correct operations.
Is mathematical software a legitimate research area?
Authors: Rice John R.
Published: April 2007

Recently the chairman of a Computer Science department wrote to solicit my views "regarding the legitimacy of mathematical software development as a research area that can stand by itself". This question arose in that department's deliberations on promotions and tenure and they sensed "a clear split in the numerical analysis community on this question. The opposing view takes the position that mathematical software development is a sub-branch of the area of numerical analysis for which the software is being developed, and is not itself sufficient to establish research credentials for a numerical analyst." The following is my response to this solicitation.
A brief description of SPARSPAK Waterloo sparse linear equations package
Authors: George Alan , Ng Esmond
Published: April 2007

Computer subroutines for solving large sparse systems of linear equations usually involve fairly complicated data structures and storage management. In most cases, the user of such subroutines simply wants top solve his problem and does not have to understand how the storage management is done, or how the matrix components are stored. Thus software for solving sparse systems of linear equations should be designed in such a way that it can insulate the user from these considerations, while still allowing the software to be used in a variety of ways.
BASIC for numerical quadrature
Authors: Kahaner David K.
Published: April 2007

Although I have been involved in the development of programs for numerical evaluation of integrals for a number of years, it was only recently that I became aware of the importance of providing such tools in BASIC. I admit to having had a built-in predjudice against people using BASIC. To me it seemed that these people were either solving trivial problems, or were too lazy to learn FORTRAN. But in the last year or so, I have been made aware that BASIC is very much an alive language with sophisticated scientific users. The growth in popularity of the microcomputer is partly responsible for this. At NBS I also see many more scientists who are not as computer oriented as those I met at Los Alamos and this has some effect too. In this talk I would like to describe a few important quadrature techniques that are essential to have and how they can be best implemented in BASIC. This seems to me a rather neglected area. There may be a few odd bits of software around in BASIC, but most are not what I would call state-of-the-art. If I am wrong about this I would be happy to be corrected. We could publish a bibliography of such programs here in the SIGNUM Newsletter. In the first section, as a convenience to those of us who are not very familiar with the language, I outline several of the differences with FORTRAN.
Summary of research activity at ICASE
Authors: Voigt Robert G.
Published: April 2007

The Institute for Computer-Applications in Science and Engineering (ICASE) is operated at the Langley Research Center of NASA by the Universities Space Research Association, a nonprofit consortium of major U.S. colleges and universities, under a contract with the Center. The Institute conducts unclassified basic research in applied mathematics, numerical analysis and computer science in order to extend and improve problem solving capabilities in science and engineering, particularly in aeronautics and space.
Summary of the Illinois-Toronto OlympiODE test results
Authors: Addison Clifford
Published: April 2007

Late in 1978, the organizers of the 1979 SIGNUM conference on ODE's at Urbana, C. W. Gear, R. D. Skeel and D. S. Watanabe, proposed that an ODE Olympics be held. The plan was to have a competition, open to any code, which would take place prior to the conference. The results of this competition, as well as a discussion on the significance of the results would be used, but the problems would be selected so that some rough assessment of the entries could be made.
Automatic recognition of non-stiffness
Authors: Shampine L. F. , Baca L. S.
Published: April 2007

An outstanding characteristic of mathematical software is assistance provided by the code in recognizing that it is unsuitable for the task posed. A critical decision in the present generation of codes for the numerical solution of the initial value problem for a system of ordinary differential equations (ODEs),(1) y' = f(x, y), a < x < b, y(a) given,is whether the problem is stiff. There are effective programs for the solution of both stiff and non-stiff problems which are, however, grossly inefficient when applied to the wrong type. Unfortunately the user does not have available the information necessary for an accurate decision.
A note on Aitken's δ
2
technique
Authors: Jones Bush
Published: April 2007

This note provides a simple solution to a problem posed by Wilkinson [1] and Ralston [2]. Aitken's δ
2
technique is widely employed in numerical analysis to obtain the limit point of a sequence. However, a problem with the technique has been the determination of when to start employing the technique in a sequence. If an application is very simple, say finding the zero of a univariate function, the technique can be employed on the sequence and validated by a simple improvement check. In more complex applications, it has been much more complicated or impossible to validate the employment of the technique.
Six language extensions to enhance the portability of mathematical software written in PL/I
Authors: Dritz Kenneth W.
Published: April 2007

As part of its revision of ANS PL/I, American National Standards Committee X3J1 is considering extensions like those described here to aid in the development of high-quality portable mathematical software.The new features include environmental enquiry functions, generalization of "restricted expressions" (compile-time expressions), liberalization of the contexts of restricted expressions, a named-literal declaration type, explicit, precision specification for constants, and a pragmatic statement for expressing conditions that an implementation must satisfy for acceptable compilation. Used together, these features will give numerical analysts access to properties of an implementation's floating-point arithmetic in exactly the ways required to ease the burden of tailoring a program's precision specifications to new environments. In many cases it will be possible to write PL/I programs that are completely self-adapting to their host environment.Effective definition of the environmental enquiry functions will require the incorporation of an explicitly parameterized model of floating-point arithmetic; the environmental enquiry functions and the results of arithmetic operations will then be consistently defined in terms of the same parameters. If an appropriate model (to be described in a future paper) is adopted by the Committee and properly integrated into the Standard, a significant advantage will be offered to numerical analysts: they will be able to state and prove theorems about their programs' error bounds by appealing directly to the Standard.In addition to describing the proposed extensions, this paper presents a careful justification and a detailed example of their intended use.None of these features has yet been adopted by X3J1. The Committee is interested in the reactions of the mathematical software community to these ideas and requests that comments be sent to the author.
Numerical mathematics at Boeing computer services
Authors: Phillips J. L. , Poole W. G.
Published: April 2007

The Energy Technology Applications (ETA) Division of Boeing Computer Services consists of over 200 professionals providing analytical and computing support to The Boeing Company and government and private industry, with particular emphasis on the energy industry. The Mathematics and Modeling staff in ETA, headed by A1 Erisman, includes over 90 mathematicians, statisticians, engineers, and physicists engaged in statistical modeling and applications, operations research, optimization, dynamic simulation, stochastic modeling, mathematical physics, and numerical analysis.