From na-net@patience.Stanford.EDU Tue Sep 26 06:23:51 1989 Received: from crfsun.EPM.ORNL.GOV by cs.utk.edu with SMTP (5.61++/2.3-UTK) id AA11260; Tue, 26 Sep 89 06:23:30 -0400 Received: from antares.mcs.anl.gov (MCS.ANL.GOV) by crfsun.EPM.ORNL.GOV (4.1/1.34) id AA04766; Tue, 26 Sep 89 06:23:47 EDT Received: from beauty.stanford.edu by antares.mcs.anl.gov (4.0/SMI-DDN) id AA21488; Tue, 26 Sep 89 05:16:21 CDT Received: from patience.stanford.edu by beauty.stanford.edu (4.0/inc-1.5) id AA09044; Sun, 24 Sep 89 21:48:41 PDT Received: from bravery.stanford.edu by patience.stanford.edu (4.0/inc-1.5) id AA22281; Sun, 24 Sep 89 21:48:02 PDT Received: by bravery.stanford.edu (4.0/inc-1.5) id AA15198; Sun, 24 Sep 89 21:48:24 PDT Date: Sun, 24 Sep 89 21:48:24 PDT From: na-net@patience.Stanford.EDU Message-Id: <8909250448.AA15198@bravery.stanford.edu> Return-Path: Subject: NA-NET distribution message Maint-Path: maintainer@na-net.stanford.edu To: na-net@patience.Stanford.EDU Reply-To: na-net@patience.Stanford.EDU Comment: requests, comments or problems to nanet@na-net.stanford.edu Comment: submissions to na@na-net.stanford.edu Status: R NA Digest Sunday, September 24, 1989 Volume 89 : Issue 37 Today's Editor: Cleve Moler Today's Topics: Checking Positive Matrices Address Change for Martin Berzins Address Change of Masaaki Shimasaki Algorithms for Radon Transforms CWI-Symposia on Parallel Scientific Computing Positions at University of Maryland Baltimore County David Kamowitz Householder Symposium XI Positions at RIACS ------------------------------------------------------- From: Stephen Boyd Date: Sat, 16 Sep 1989 9:26:20 PDT Subject: Checking Positive Matrices Does anyone know of an algorithm for determining whether a matrix is P or P0, that is NOT combinatoric in the size of the matrix? (a matrix is P if the determinants of all principal submatrices are positive). I am not interested in algorithms that work for some matrices (eg symmetric (!!), or less trivially, matrices with negative offdiagonal elements); the algorithm must work for general matrices. Stephen Boyd boyd@isl.stanford.edu ------------------------------ From: Martin Berzins Date: Mon, 18 Sep 89 09:37:04 EDT Subject: Address Change for Martin Berzins Having finished my sabbatical at RPI, from 24th September my new email address will be martin@dcs.leeds.ac.uk Martin Berzins. ------------------------------ From: Masaaki Shimasaki Date: Tue, 19 Sep 89 14:11:56 JST Subject: Address Change of Masaaki Shimasaki Please change the E-mail address of Simasaki at Data Processing Center, Kyoto University to simasaki@sun4.cc.kyushu-u.junet Thank you. simasaki@sun4.cc.kyushu-u.junet ------------------------------ From: Per Christian Hansen Date: Wed, 20 Sep 89 14:07:18 -0100 Subject: Algorithms for Radon Transforms NUMERICAL ALGORITHMS FOR RADON AND INVERSE RADON TRANSFORMS Does anybody on the na-net have good numerical algorithms for computing the Radon transform, and for performing the inverse Radon transformation? Since this is a very general problem, let me add that I'm particularly interested in algorithms for use in seismics. I'm fully aware that the inverse Radon transform is an ill- posed problem and, preferably, should be treated with this aspect in mind. However, I do not know the degree of ill- posedness of the problem, i.e. the decay rate of the singu- lar values of the Radon integral operator. Any hints, comments or other advice is welcome. Per Christian Hansen UNI-C (the Danish University Computing Center) Building 305 Technical University of Denmark DK-2800 Lyngby Denmark email: na.phansen @ na-net.stanford.edu ------------------------------ From: Herman te Riele Date: Thu, 21 Sep 89 16:56:06 +0200 Subject: CWI-Symposia on Parallel Scientific Computing C A L L F O R A B S T R A C T S CWI-SYMPOSIA ON PARALLEL SCIENTIFIC COMPUTING in collaboration with TUD, UvA and IMACS In collaboration with TUD (Technical University Delft), UvA (University of Amsterdam) and IMACS (International Association for Mathematics and Computers in Simulation), CWI will organise five one-day Symposia on Parallel Scientific Computing. Dates are: 2 Febr., 6 April, 8 June, 7 Sept. and 2 Nov. 1990. Place is CWI Amsterdam, The Netherlands. Attention will focus on new developments in numerical algorithms for parallel computing systems, on software tools for parallel computing (including libraries) and on applications in science and technology (e.g., fluid dynamics, mechanics, chemistry). Depending on possible external funding, a number of leading experts in these fields will be invited to speak. The organising committee consists of Prof.dr. Th.J. Dekker (UvA), Dr.ir. H.J.J. te Riele (CWI) and Prof.dr. H.A. van der Vorst (TUD and CWI). Abstracts of possible contributions to the first three meetings (2 Febr., 6 April and 8 June 1990) are solicited now. The deadline for submission of abstracts is Nov. 1, 1989. Notification of acceptance will be sent by Jan. 1, 1990. A special issue of the IMACS Journal "Applied Numerical Mathematics" will be devoted to the proceedings of the symposia. Contributions will be subject to the usual refereeing process of IMACS. Please send for electronic application form. (On behalf of) the organising committee, Herman J.J. te Riele Centre for Mathematics and Computer Science (CWI) Kruislaan 413 1098 SJ Amsterdam The Netherlands e-mail: herman@cwi.nl ------------------------------ From: Thomas Seidman Date: 21 Sep 89 13:30:00 EDT Subject: Positions at University of Maryland Baltimore County POSITION ANNOUNCEMENT --- UMBC The Department of Mathematics and Statistics at the University of Maryland Baltimore County has been authorized to recruit for three positions for the Fall of 1990. At least one of these will be at a senior level; at least one will be in Statistics. The Department has strengths in control theory and optimization, in ordinary and partial differential equations and mathematical modelling, in numerical analysis and scientific computing, and in probability and statistics. It seeks strong applicants in these or related areas. Interested candidates should send a curriculum vitae, a list of publications, and three letters of reference to: James M. Greenberg, Chairman Department of Mathematics and Statistics University of Maryland Baltimore County Baltimore, MD 21228 Applicants will be considered until three suitable candidates have been found. THE UNIVERSITY IS AN EQUAL OPPORTUNITY EMPLOYER AND SPECIFICALLY INVITES APPLICATIONS FROM WOMEN, MINORITIES, AND DISABLED PERSONS. ------------------------------ From: Robert Voigt Date: Fri, 22 Sep 89 08:22:09 EDT Subject: David Kamowitz On September 16 David Kamowitz died of complications associated with a long bout with cancer. David came to ICASE from Wisconsin three years ago. He struggled with his disease for over two years, admonishing his doctors to keep trying up until the very end. He was one of the most courageous people I have known and I consider myself fortunate to have been associated with him. Bob Voigt ------------------------------ From: Ake Bjorck Date: Fri, 22 Sep 89 14:50:43 +0200 Subject: Householder Symposium XI THE HOUSEHOLDER SYMPOSIUM XI MEETING ON NUMERICAL ALGEBRA The Householder Symposium XI on numerical algebra will be held during the week of June 18--22, 1990 at Tylosand, Halmstad on the west coast of Sweden. This meeting is the eleventh in a series, previously called the Gatlinburg Symposia. It has been agreed to rename all subsequent Gatlinburg Symposia to honor Alston S. Householder, one of the pioneers in Numerical Linear Algebra and organizer of the first four Gatlinburg meetings. The meeting is an international conference of experts in the field of Numerical Algebra. The format of the meeting is a sequence of invited papers during the day and special workshops organized by the participants in the evening. There is no formal program, but traditionally a few topics are emphasized. For this meeting they will be large scale nonsymmetric linear algebra problems, least squares, and matrix inertia and stability. The meeting is being organized by the Householder committee, in cooperation with the SIAM Activity Group on Linear Algebra. Chairman of the committee for this meeting, and in charge of the local organization is Ake Bjorck of Linkoping University, Sweden. The traditional format of the Householder Symposia requires that the attendance is limited. The organizing committee invites all qualified persons to apply to attend. The application should consist of a vita and an extended abstract (about two pages) of a paper you would present if invited to speak. The latter will be used by the committee in planning the program. Material should be sent before November 1, 1989 to Ake Bjorck Department of Mathematics Linkoping University S-581 83 Linkoping, SWEDEN The Gatlinburg Conferences are international workshops on the theoretical and numerical aspects of linear algebra and its application. They were started by Alston S. Householder and initially held at Gatlinburg, Tennessee, approximately once every three years. After the first four meetings it was decided to hold the conferences under the same name at varying locations. The custom has become to have every third meeting in Europe. For a review of the earlier meetings see an article in SIAM Review [1977]. A complete list of previous meetings is given below: I. April 1961 Gatlinburg, Tennessee A. S. Householder II. October 1963 Gatlinburg, Tennessee F. Olver III. April 1964 Gatlinburg, Tennessee A. S. Householder IV. April 1969 Gatlinburg, Tennessee A. S. Householder V. April 1972 Los Alamos, New Mexico A. S. Householder VI. December 1974 Hopfen am See, Germany F. L. Bauer VII. December 1977 Asilomar, California G.H. Golub VIII.July 1981 Oxford, England J.H. Wilkinson IX. July 1984 Waterloo, Canada J.A. George X. October 1987 Fairfield Glades, Tennessee G.W. Stewart The Gatlinburg meetings brings together theoreticians, numerical analysts, and application researchers from all over the world. During the day, there are lectures (no parallel sessions) by people judged to be doing especially interesting work in their areas. In the evenings, the participants organize special sessions or minisymposia over areas of current interest. Traditionally the interaction is very open and intense, and many workers attribute some of their best results to ideas that originated at a Gatlinburg conference. The meetings have played an important part in the evolution of scientific computing, and it is hard to overstate the role these conferences have played in fostering and sustaining international cooperation in numerical algebra. Attendance at the Gatlinburg Conferences is by invitation, and procedures have been devised that hopefully insure that a fair selection is made. It is anticipated that 100-120 people will be invited to the present meeting. Even though several open meetings are held in linear algebra, these conferences are unique in that here the best people in the field from all countries have a chance to get together and interact informally. Hotel Tylosand is situated by the sea on the west coast of Sweden. The hotel has recently been renovated and modernized and is a conference center of the best international class. The location is removed from any big cities and offers excellent opportunities for physical exercise. Room and buffet breakfast is approximately $65 single and $60 double occupancy. It is hoped that the meeting can be run with the same modest registration fee $50 as the previous meeting at Fairfield Glades. ------------------------------ From: Rich Sincovec Date: Fri, 22 Sep 89 14:55:07 PDT Subject: Positions at RIACS INSTITUTE: RIACS JOB TITLE: FACILITY RESEARCH ASSOCIATE LOCATION: MOUNTAIN VIEW, CA at NASA AMES The Research Institute for Advanced Computer Science (RIACS) is an institute of the Universities Space Research Association operating under a cooperative agreement with the NASA Ames Research Center and is devoted to the conduct of research in computer science aimed at the challenging problems faced by NASA. Current research programs include development, integration, and evaluation of advanced computer science technologies supporting the use of multiple resources connected by networks, the study of advanced numerical algorithms and parallel computing architectures, and memory models for robotics and other applications. FACILITY DESCRIPTION: The RIACS computing facility serves our staff of approximately forty individuals and consists of the following equipment: Sequent Balance 21000s, Encore Multimax, Ardent, Stellar, NeXT, various X Stations, network access to NASA Ames computers including Cray Y_MP, Cray 2 and CM-2, 26 Sun 3 workstations with 3 dedicated file servers running Sun OS 4.0, uucp server, internet gateway to BARRNET (NSFNET). The RIACS facility is principally based on UNIX and X Windows. RESPONSIBILITIES INCLUDE: * Systems programming and maintenance on the computing facility. * Systems administration for the Sun network. * Applications programming supporting research projects in scientific computing with an emphasis on numerical algorithms for parallel computer architectures. * Frequent interaction with RIACS and NASA scientists. EDUCATION/EXPERIENCE * M.S. in Computer Science or equivalent experience * Two or more years experience working with UNIX, including experience with the kernel and net-working. * Ability to work well with people and excellent communications skills * U.S. Citizenship or Permanent Residence. INTERESTED PARTIES: Send your resume to: sincovec@riacs.edu Richard Sincovec RIACS - Research Institute for Advanced Computer Science Mail Stop 230-5 NASA Ames Research Center Moffett Field, CA 94035 Office Phone: (415)694-4342 FAX Number: (415)961-8467 ------------------------------ End of NA Digest ************************** -------