From surfer.EPM.ORNL.GOV!nacomb Sun Mar 24 13:08:05 0500 1991 Received: by pyxis; Sun Mar 24 13:08 EST 1991 To: pyxis!ehg Received: by inet.att.com; Sun Mar 24 13:08 EST 1991 Received: by surfer.EPM.ORNL.GOV (5.61/1.34) id AA10632; Sun, 24 Mar 91 13:08:05 -0500 Date: Sun, 24 Mar 91 13:08:05 -0500 From: nacomb@surfer.EPM.ORNL.GOV (NA-NET) Message-Id: <9103241808.AA10632@surfer.EPM.ORNL.GOV> Subject: NA Digest, Vol. 91, No. 12 Comment: Submissions for NA News Digest, mail to na.digest@na-net.ornl.gov. Comment: Information about NA-NET, mail to na.help@na-net.ornl.gov. Comment: Comments about the NA-NET, mail to nanet@na-net.ornl.gov. Apparently-To: ehg@research.att.com NA Digest Sunday, March 24, 1991 Volume 91 : Issue 12 Today's Editor: Cleve Moler Today's Topics: A Wonderful Report Applied Math Is ... Reciprocal Pythagorean Sums Query About Floating Point Models First Annual Large Dense Linear System Survey Request for Domain Decomposition Bibliography Venice Summer School on Applied Mathematics Workshop for Industry in Venice Positions at Delft University of Tehcnology Positions at Australian National University Professur C4 fuer Mathematik in Aachen Contents, Linear Algebra and Its Applications ------------------------------------------------------- From: Gene Golub Date: Mon, 18 Mar 91 14:07:44 PST Subject: A Wonderful Report Charlie Van Loan has written a wonderful report on recent developments in matrix computations; it is entitled , "A Survey of Matrix Computations." The report would make an excellent basis for a course or seminar. If you are interested in receiving a copy, send a msg to Charlie (na.vanloan@na-net) and ask for a copy. I'm sure you'll find it of interest. Gene ------------------------------ From: Joe Grcar Date: Thu, 21 Mar 91 16:54:31 PST Subject: Applied Math Is ... I recall reading an essay titled "applied math is bad math" by Halmos or some such, but I don't remember where. Can anyone supply a reference? Joe Grcar, na.grcar ------------------------------ From: George Miel Date: Mon, 18 Mar 91 19:18 PST Subject: Reciprocal Pythagorean Sums Reciprocal Pythagorean sums, 1/sqrt(a*a + b*b) (*) are needed in certain applications, eg for computing Givens rotations in linear algebraic methods. For Pythagorean sums, Moler and Morrison have presented an algorithm that is simple, robust, and portable. Specifically, the algorithm is attractive because it avoids range-reduction and overflow default handling. However, the approximation of (*) based on m iterations of the Moler-Morrison algorithm followed by reciprocation requires a total of 2m+1 divisions. For throughput intensive processors with no hardware division, this approach is too slow. I was therefore led to the PROBLEM: Find a division-free algorithm for reciprocal Pythagorean sums with similar properties to the Moler-Morrison procedure, namely, with fast convergence and no range-reduction nor overflow/underflow for a "large" set of pairs a,b of machine numbers (say IEEE standard 754 floating point). I have tinkered with this deceptively simple problem and so far the best I have for single precision accuracy is an approximation for 1/sqrt(c) using a 3rd degree polynomial approximation for the seed followed by one iteration of Olver's method on f(x)=1/x**2-c, at a cost of 9 mult-adds. However, this approach (as well as the usual division-free Newton-Raphson method for 1/sqrt) requires setting c=a*a + b*b followed by range reducing c to a small interval. Does anyone know of better alternatives? George Miel, Hughes Research Laboratories, 3011 Malibu Cyn Rd, Malibu CA 90265 213-317-5841 miel@csfvax.hac.com ------------------------------ From: Bill White Date: 15 Mar 91 17:02:00 GMT Subject: Query About Floating Point Models As part of the Ada 9X effort we considering changes to the definition of Ada floating point number representation. We are looking at two different models: the Brown model [1] and the LCAS model [2]. We are informally soliciting comments on the following topics. 1.) Is there any other floating point model which is likely to be a useful candidate for the Ada 9X standard? 2.) Which of floating-point models deal best with the very important issues of portability and robustness? In particular, I am concerned here with the essential difference between the non-determinism of the Brown model and the determinism of the LCAS model. We are inclined to favor the Brown model, in the interests of portability. As even numerics tyros (like me) know, a major problem with numeric computations is the whimsical nature of optimization algorithms. It is especially problematic to tell when operands will be in extended precision registers and when they will be dumped to memory. The attractive aspect of the Brown model is that the non-determinism explicitly hides the optimization effects. The more highly detemined LCAS model requires that the numerical analyst know the optimizer's algorithm completely. This is not always possible, or even desirable, as the algorithms may change and improve with different compiler releases. The particular things I am interested in are: 1.) Pointers to any other reasonable floating point models. Since we are working in an Ada framework, the models must be general enough to analyze IEEE floating point, but not be restricted to a single architecture. 2.) References in the literature to analyses of numerical algorithms which use the floating-point model explicitly. The only one I know of is the one in Brown's original paper. I am certain there are more, but as I am not a numerical analyst by training I am not sure how or where to proceed. Any help would be appreciated. Peace, Bill White [1] W.S. Brown, A Simple but Realistic Model of Floating Point Computations, ACM Transactions on Mathematical Software, vol 7, (1981) pp. 445-480. [2] Mary Payne, Craig Schaffert, and Brian Wichmann, Proposal for a Language Compatible Arithmetic Standard, appeared in SIGPLAN Notices, vol 25, no 1., January 1991, pp. 59-86. ------------------------------ From: Alan Edelman Date: Sat, 23 Mar 91 23:27:24 PST Subject: First Annual Large Dense Linear System Survey THE FIRST ANNUAL LARGE DENSE LINEAR SYSTEM SURVEY Without realizing it, about a year ago, I initiated the 0th annual large dense linear system survey here in NANET. I've had so many requests for a repeat survey that I decided to formalize the process by making it a yearly event. (My calendar file should remind me to repeat this next year.) I understand the NANET list has grown considerably since last time, so this survey should reach many more people. By default, none of the information you supply will be anonymous, however I will keep any information strictly confidential upon request. All of these questions relate to large DENSE linear systems. Feel free to interject any comments between the lines, etc. Results will be tallied into a LaTeX paper and will be available by anonymous FTP from math.berkeley.edu. Name __________________ Address _______________ _______________ _______________ _______________ Type of Institution ___ University ___ Independent Research Lab ___ Aircraft industry ___ Supercomputer Manufacturer ___ Other Largest matrix size that you solved n=_________ Length of time ___________ (seconds, hours, weeks, ...) on which machine ________________ Matrix was generated from ___ Moment Methods ___ Panel Methods for Lifting Potential Flow ___ Panel Methods for Potential Flow ___ Randomly (specify the distribution) ___ Other Solution method used was ____ LU factorization ____ An iterative Method (Please specify___________) (If an iterative method was used, did you take advantage of symmetry, diagonal dominance, or any property at all?) The solver was ___ your own ___ from a package (Please specify___________________) The accuracy of the solution obtained ____ was clearly good (Specify how you know ____________________) ____ seems okay, but you are not really sure ____ is unknown Any other comments, suggested questions for next year, etc? I'm aware that aircraft manufacturers and supercomputing companies would be most interested in these results, but might be reluctant to reveal their own secrets. I would like to urge such manufacturers to feel free to mail me anonymous responses by surface mail even without return addresses and names. I will guarantee anonymity in any case upon request. Everyone will so benefit. All I ask is that responses be truthful. I trust that the academics out there who are doing this will be more than happy to be forthcoming. edelman@math.berkeley.edu Alan Edelman Dept of Mathematics University of California Berkeley, CA 94720 ------------------------------ From: Jeff Scroggs Date: Sat, 23 Mar 91 17:00:16 -0500 Subject: Request for Domain Decomposition Bibliography Louise Perkins and Jeff Scroggs would like to request bibliographic data on heterogeneous domain decomposition. We are interested in papers that deal with domain decomposition techniques for the numerical solution of PDEs in which different modeling equations are used in different subdomains. This data will be collected into a publicly available report (issued by ICASE, NASA Langley Research Center). In order that this database be manageable, we have the following request: Format: Bibliographic data should be in bibtex format. A set of keywords is requested as part of the format. Medium: Email messages to Louise Perkins or Jeff Scroggs. Date: References for the first version should be in by April 5. Assistance: To assist with placing the data in bibtex format, send a request to either of us for the C program BIBINPUT. This program will interactively prompt you for the data, and produce a file with the formatted entries. Disclaimer: We are trying to keep this bibliography focused, hence submissions that do not obviously deal with heterogeneous domain decomposition will be eliminated. Louise Perkins 54-1420 MIT Cambridge, MA 02139 (617)253-1291 perkins@pimms.mit.edu Jeffrey S. Scroggs Box 8205 Mathematics Department North Carolina State University (919)737-7817 scroggs@matjfs.ncsu.edu ------------------------------ From: Renato Spigler Date: Tue, 19 Mar 91 14:17:19 SET Subject: Venice Summer School on Applied Mathematics Between June 17 and 28, 1991, a Summer School will be held in Venice, Italy, downtown, at the Ateneo Veneto (Campo S.Fantin 1897,S.Marco,30124 Venice). Speakers and topics will be 1) G.H.GOLUB, Stanford, "Matrices,moments,and orthogonal polynomials", 2) E.HAMEIRI, Courant Institute, NYU, "Localized instabilities in MHD plasmas and in classical fluids", 3) P.A.MARKOWICH, TU-Berlin and Purdue, "Mathematical modelling of semiconductors", 4) G.MILTON, Courant Institute, NYU, "Exploring the properties of composite materials". The Scientific Committee includes V.Boffi, F.Brezzi, G.Frosali, and D.Trigiante. Attendence will be limited to 50 participants. Send applications to Renato SPIGLER, Dipartimento di Metodi Mod. Mat. Sci. Appl., Universita' di Padova, Via Belzoni, 7-35131 Padova (Italy), phone 0039-49-83 19 14, 83 19 01 , fax 0039-49-83 19 95, e-mail spigler at ipduniv.bitnet. The event is sponsored/jointly organized/with the collaboration of Universita' di Padova Gruppo Nazionale per la Fisica Matematica del CNR UNESCO Courant Institute of Mathematical Sciences, NYU SIAM Renato Spigler ------------------------------ From: Renato Spigler Date: Tue, 19 Mar 91 14:52:44 SET Subject: Workshop for Industry in Venice On May 3, 1991, there will be a one-day workshop on Mathematics for Industry, in Venice, Italy, at the Istituto Veneto di Scienze, Lettere e Arti (Campo S.Stefano, S.Marco 2945). This event is promoted by ALPE ADRIA, the J. Kepler University of Linz, S.A.S.I.A.M.-Tecnopolis, and the University of Padova. It will also held under the auspices of the European Consortium for mathematics in the Industry (ECMI), and the Consorzio Venezia-Ricerche. Four mathematicians from the Academia and two or three from the industrial worldwill present a few case studies, as examples of successful collaboration between the two environments. A free, informal discussion willbe organized in the afternoon, and, possibly, some new, open problems will be introduced for the purpose of establishing new collaborations. The event is aimed mainly to the Alpe Adria community. Renato Spigler (phone 0039-49-831914, 831901, fax 831995, e-mail spigler at ipduniv.bitnet) ------------------------------ From: Ed F. Deprettere Date: Tue, 19 Mar 91 17:51:00 +0100 Subject: Positions at Delft University of Tehcnology Faculty and PH.D candidate positions available, Network Theory Section (Microelectronics Group), Department of Electrical Engineering, Delft University of Technology, Delft The Netherlands. Junior Scientist Position and Ph.D. Candidate Position In connection with the project Modeling and Determination of Parasitics in Submicron VLSI Layouts at the Network Theory Section of the Faculty of Electrical Engineering at Delft University of Technology, Delft, The Netherlands, the above mentioned positions are currently open. The project aims at an advanced system for the modeling of submicron IC interconnect structures. The ongoing miniaturization of IC's-0.5 micron feature size is quickly becoming available-causes new design related problems. Because of their minute dimensions, the circuit elements behave differently. One aspect of this changed behavior is the relative increase of parasitic resistances, ground capacitances and coupling capacitances. An IC designer who does not properly account for these effects runs the risk that his design does not function as intended. The problem is especially severe in combined analog/digital (e.g. BICMOS) circuits. Not only are these parasitic effects becoming more prominent, they are also becoming more difficult to determine: traditional, heuristic methods are inadequate. Instead, completely new methods are necessary to capture these effects into suitable models. The goal of the present case project is to develop these methods and models. TASK You will be part of a team carrying out research to develop such a modeling system. You will build on the knowledge available in the laboratory, as was developed in a precursor project. After a thorough study of those results, you will extend the theory in order to come to a system capable of delivering accurate (but not over-accurate) models that enable designers to predict the crosstalk between different subcircuits. Relevant physical aspects are e.g.: + interconnect capacitances of non-planar structures, + capacitive effects of diffused conductors, + the resistive nature of the substrate. The newly developed theory will lead towards a prototype implementation in the Nelsis IC design system. REQUIREMENTS The positions can be characterized as multi-disciplinary: electrical engineering, physics, linear algebra, numerical mathematics and computer science are all relevant. Applicants should have a grade in one of these disciplines, preferably their education and/or experience shows a good mix of these disciplines. It is the intention that the research will lead to dissertations. NOTE An appointment will be temporal with a duration of 4 years. INFORMATION For more information, please apply to Dr. N.P. van der Meijs tel. +31-15-786258 email: nick@et.tudelft.nl or Prof. P. Dewilde tel. +31-15-786234, email: dewilde@dutentb.et.tudelft.nl. ------------------------------ From: Mike Osborne Date: Wed, 20 Mar 91 17:50:10 MEZ Subject: Professur C4 fuer Mathematik in Aachen RHEINISCH-WESTFAELISCHE TECHNISCHE HOCHSCHULE AACHEN In der Mathematisch-Naturwissenschaftlichen Fakultaet ist am Institut fuer Geometrie und Praktische Mathematik eine P R O F E S S U R C 4 F U E R M A T H E M A T I K (Fiebiger-Programm) zu besetzen. Erwartet wird die Vetretung des Faches Mathematik in Forschung und Lehre und die Mitwirkung an der Ausbildung von Studierenden der Mathematik, Ingenieur- und Naturwissenschaften. Zu den Aufgaben des Institutes gehoert das Vorlesungsangebot in Numerik sowie Darstellender Geometrie. Erwuenscht ist ein Forschungsgebiet aus der Numerischen Analysis, das Bezug zu Ingenieur- und Naturwissenschaften hat, z.B. Numerische Mathematik der Differentialgleichungen oder/und numerisch-geometrische Verfahren fuer hoeher dimensionale Probleme. Einstellungsvoraussetzung sind Habilitation oder gleichwertige wissenschaftliche Leistungen sowie paedagogische Eignung. Die Bewerbung von Schwerbehinderten ist erwuenscht. Bewerberinnen und Bewerber werden gebeten, sich mit den ueblichen Unterlagen (Lebenslauf, Darstellung des wissenschaftlichen bzw. beruflichen Werdegangs, Schriftenverzeichnis) bis zum 15. Mai 1991 an den Dekan der Mathematisch-Naturwissenschaftlichen Fakultaet der RWTH Aachen Templergraben 64 D-5100 Aachen. Auch Hinweise auf geeignete Persoenlichkeiten sind erwuenscht. ------------------------------ From: Richard Brualdi Date: Wed, 20 Mar 91 10:25:48 cst Subject: Contents, Linear Algebra and Its Applications Table of Contents of Volume 150 of LAA, May 1991: Proceedings of the First Conference of the International Linear Algebra Society Special Editors: Wayne Barrett, Daniel Hershkowitz, and Donald Robinson George W. Soules (Princeton, New Jersey) The Rate of Convergence of Sinkhorn Balancing 3 Marvin Marcus (Santa Barbara, California) Multilinear Methods in Linear Algebra 41 Russell Merris (Hayward, California) Almost All Trees Are Co-immanantal 61 Daniel J. Scully (Saint Cloud, Minnesota) Maximal Rank-One Spaces of Matrices Over Chain Semirings. I. u-Spaces 67 Ronald J. Stern (Montreal, Quebec, Canada) and Henry Wolkowicz (Waterloo, Ontario, Canada) Invariant Ellipsoidal Cones 81 Bob Grone and Steve Pierce (San Diego, California) Extremal Positive Semidefinite Doubly Stochastic Matrices 107 Shmuel Friedland (Chicago, Illinois) Pairs of Matrices Which Do Not Admit A Complementary Triangular Form 119 Jerome Dancis (College, Park, Maryland) Invertible Completions of Band Matrices 125 R. Loewy, D. R. Shier, and C. R. Johnson (Williamsburg, Virginia) Perron Eigenvectors and the Symmetric Transportation Polytope 139 I. Gohberg (Ramat Aviv, Israel), M. A. Kaashoek (Amsterdam, The Netherlands), and H. J. Woerdeman (La Jolla, California) A Note on Extensions of Band Matrices With Maximal and Submaximal Invertible Blocks 157 Robert Grone (San Diego, California) On the Geometry and Laplacian of a Graph 167 Chi-Kwong Li (Williamsburg, Virginia) and Nam-Kiu Tsing (College Park, Maryland) G-Invariant Norms and G(c)-Radii 179 Michael E. Lundquist (Provo, Utah) and Charles R. Johnson (Williamsburg, Virginia) Linearly Constrained Positive Definite Completions 195 Rafael Bru (Valencia, Spain), Leiba Rodman (Williamsburg, Virginia), and Hans Schneider (Madison, Wisconsin) Extensions of Jordan Bases for Invariant Subspaces of a Matrix 209 R. A. Brualdi (Madison, Wisconsin) and J. Csima (Hamilton, Ontario, Canada) Small Matrices of Large Dimension 227 Yik-Hoi Au-Yeung and Che-Man Cheng (Hong Kong) Permutation Matrices Whose Convex Combinations Are Orthostochastic 243 Jeffrey L. Stuart (Hattiesburg, Mississippi) and James R. Weaver (Pensacola, Florida) Matrices That Commute With a Permutation Matrix 255 Jean H. Bevis and Frank J. Hall (Atlanta, Georgia) Integer LU-Factorizations 267 Pal Rozsa (Budapest, Hungary), Roberto Bevilacqua, Francesco Romani, and Paola Favati (Pisa, Italy) On Band Matrices and Their Inverses 287 Charles R. Johnson (Williamsburg, Virginia) and Erik A. Schreiner (Kalamazoo, Michigan) Explicit Jordan Form for Certain Block Triangular Matrices 297 Jorma Kaarlo Merikoski (Tampere, Finland) On c-Norms and c-Antinorms on Cones 315 R. B. Bapat (New Delhi, India) An Interlacing Theorem for Tridiagonal Matrices 331 Olga Taussky and John Todd (Pasadena, California) Another Look at a Matrix of Mark Kac 341 M. C. Gouveia (Coimbra, Portugal) and R. Puystjens (Gent, Belgie@a2) About the Group Inverse and Moore-Penrose Inverse of a Product 361 Hans Joachim Werner (Bonn, Germany) Some Further Results on Matrix Monotonicity 371 Yair Censor (Haifa, Israel) and Stavros A. Zenios (Philadelphia, Pennsylvania) Interval-Constrained Matrix Balancing 393 Shmuel Friedland (Chicago, Illinois) Quadratic Forms and the Graph Isomorphism Problem 423 H. Bart (Rotterdam, The Netherlands) and H. K. Wimmer (Wurzburg, Germany) Simultaneous Reduction to Triangular and Companion Forms of Pairs of Matrices: The Case rank(I_AZ)=1 443 Wayne Barrett, Donald Robinson (Provo, Utah), and Daniel Hershkowitz (Haifa, Israel) REPORT: Inaugural Conference of the International Linear Algebra Society, 12-15 August 1989, Brigham Young University, Provo, Utah, USA 463 Special Issues in Progress 1. Interior Point Methods for Linear Programming; special editors are D. Gay, M. Kojima, and R. Tapia. To appear as Volume 152, July 1, 1991. 2. Iterations in Linear Algebra and Its Applications (Dedicated to G. H. Golub, R. S. Varga, and D. M. Young); special editors are O. Axelsson, J. de Pillis, M. Neumann, W. Niethammer, and R. J. Plemmons. To appear as Volumes 154/155, August/September 199 3. Algebraic Linear Algebra; special editors are Robert M. Guralnick, William H. Gustafson, and Lawrence S. Levy. To appear as Volume 157, October 15, 1991. 4. Proceedings of the Auburn 1990 Matrix Theory Conference; special editors are David Carlson and Frank Uhlig. Submission deadline: August 1, 1990. Details provided with the conference announcement. 5. Proceedings of the Sixth Haifa Conference on Matrix Theory; special editors are A. Berman, M. Goldberg, and D. Hershkowitz. Submission deadline: October 1, 1990. Details provided with the conference announcement. 6. Proceedings of the International Workshop on Linear Models, Experimental Designs and Related Matrix Theory, (August 6-8, 1990, Tampere, Finland); special editors are Jerzy K. Baksalary and George Styan. Submission deadline: October 31, 1990. Details provided with the conference announcement. 7. Proceedings of the Second NIU Conference on Linear Algebra, Numerical Linear Algebra and Applications, (May 3-5, 1991, Northern Illinois University, DeKalb, Illinois); special editors are Biswa Dutta and Robert Plemmons. Submission deadline: July 31, 1991. Details provided with the conference announcement. ------------------------------ End of NA Digest ************************** -------