From na-net@na-net.stanford.edu Mon Jun 26 09:15:48 1989 Received: from beauty.stanford.edu by antares.mcs.anl.gov (4.0/SMI-DDN) id AA03990; Mon, 26 Jun 89 09:14:44 CDT Received: from patience.stanford.edu by beauty.stanford.edu (4.0/inc-1.5) id AA11969; Sun, 25 Jun 89 12:48:04 PDT Received: from bravery.stanford.edu by patience.stanford.edu (4.0/inc-1.5) id AA05366; Sun, 25 Jun 89 12:39:30 PDT Received: by bravery.stanford.edu (4.0/inc-1.5) id AA05813; Sun, 25 Jun 89 12:52:00 PDT Date: Sun, 25 Jun 89 12:52:00 PDT From: na-net@na-net.stanford.edu Message-Id: <8906251952.AA05813@bravery.stanford.edu> Return-Path: Subject: NA-NET distribution message Errors-To: nanet@na-net.stanford.edu Maint-Path: maintainer@na-net.stanford.edu To: na-net@na-net.stanford.edu Reply-To: na-net@na-net.stanford.edu Comment: requests, comments or problems to nanet@na-net.stanford.edu Comment: submissions to na@na-net.stanford.edu Comment: alternate address: na%na-net@score.stanford.edu Status: RO NA Digest Sunday, June 25, 1989 Volume 89 : Issue 25 Today's Editor: Cleve Moler Today's Topics: Professorship in Trondheim Freund Wins Award Mininization Problem Positions at Bergen Scientific Centre Vector/Parallel Polynomial Arithmetic Scientific programming in C++ No NA News Digest Next Week ------------------------------------------------------- From: Hans Munthe-Kaas Date: 19 Jun 89 10:19 +0200 Subject: Professorship in Trondheim The Norwegian Institute of Technology Division of Mathematical Sciences Full Professor of Mathematics (Numerical Analysis) The Norwegian Institute of Technology invites applications for a tenured position as Full Professor of Mathematics (Numerical Analysis). The Division of Mathematical Sciences is part of the Department of Physics and Mathematics, and currently has 23 faculty positions, 11 of which are full professorships. The Division offers a program in Industrial Mathematics leading to the engineering degree of siv.ing. (at M.S. level), and has a doctoral program leading to the dr.ing. degree. The program in Industrial Mathematics consists of courses in mathematics, numerical analysis and statistics, with a general emphasis on mathematical modelling. Research interests of the current faculty in numerical analysis include numerical quadrature, spline approximations, numerical solution of ordinary differential equations and numerical linear algebra. Special emphasis will be placed on qualifications of candidates in areas of numerical analysis with relevance to numerical modelling using vector or prallel computing algorithms; in particular qualifications within numerical linear algebra, numerical solution of differential equations, and numerical optimization. Applicants are sought who show significant research accomplishments as well as serious concern for teaching, and commitment to initiating and promoting research. The closing date for receipts of applications is September 1, 1989. The Professor is engaged on the condition that he/she at any time participates in teaching and examination work in accordance with the relevant program of study, and furthermore he/she must accept, without compensation, any revisions made by statutory law or royal decree to curricula, pension arrangements and retirement age. A letter of application including a curriculum vitae and a list of publications should be addressed to The King and sent to: The University of Trondheim The Norwegian Institute of Technology Personell Section N-7034 Trondheim Norway. In addition, reprints and preprints should be sent, in quadruplicate, to the same address, no later than one month after the closing date. Work in progress, referred to in the letter of application, must arrive within three months after the closing date. Further information is available from the above address. ------------------------------ From: Rich Sincovec Date: Wed, 21 Jun 89 17:48:10 -0700 Subject: Freund Wins Award Roland Freund was recently informed that he is the recipient of the "Heinz- Meier-Leibniz Award". It is awarded by the German Secretary of Education and Science. It is a one time award related to the anniversary of some important event in science (possibly Leibniz's birthday). It is awarded in three different fields: Public Law, Applied Math, and some engineering discipline. The award honors important contributions of junior scientists not older than 33 years. Roland will receive the Applied Math Award which also includes a monetary award. Roland did not know that he was nominated for this award until he received notice that he was the recipient of the award. A committee selected Roland based on the quality and the importance of his research papers. Roland will receive the award this week in a ceremony held in an old castle which is part of the University in Muenster. Congratulations, Roland! ------------------------------ From: AlBert DeKnuydt Date: Thu, 22 Jun 89 18:11:27 GMT Subject: Mininization Problem This MAIL contains a description of a problem on numerical minimisation and numerical differentiation. The domain of the problem is image processing. 1) Function description : The rather complicated function to minimize depends on 5 variables. These 5 variables define an image of which a histogram is calculated. The function result is the following operation on this histogram. (In fact the entropy) N(i) = number of occurrences of value i N = total number of occurrences function_result = - SUM [N(i)/N] * blog [(N(i)/N)] all i with N(i) <> 0 One single function evaluation takes about 3 minutes CPU on a VAX 8530. 2) What we tried up to now : We tried the following NAG routines. E04JAF : Quasi Newton algorithm using function values only, easy-to-use version. Problem : accurracy of result nor function evaluation not controllable. Routine doesn't use large enough steps towards the minimum. E04JBF : Quasi Newton algorithm using function values only, comprehensive (= not "easy-to-use" ?) version. Problem : steps too small. Routine E04HBF, used to determine initial step length for making difference approximations to the partial derivatives of the target function, expects target function to be of machine accuracy. Because our function is essentially discrete, this is questionable. E04VCF : Sequential QP (Quadratic Programming) method, using first derivatives. Problem is now with the routine to calculate these derivatives. It almost always returns with a diagnostic complaining about accuracy (forward and central difference estimates don't agree to half a decimal place). When we check these derivatives with E04ZCF, it says it doubts about the correctness of the derivatives. Probably, the cause is the slightly discrete character of the target function. (We use MARK 12 release of the NAG library, if this is of any importance) 3)Questions Anybody has an idea : What the reason of the failure of the NAG routines might be ? And how to solve this ? Of another way to minimize this kind of function ? eMAIL deknuydt@kulesat.uucp UUCP deknuydt%kulesat.uucp@blekul60 BITNET B. DeKnuydt & J. Smolders K.U.Leuven ESAT/MI2 Kardinaal Mercierlaan 94 B-3030 Heverlee-Leuven B E L G I U M ------------------------------ From: Pat Gaffney Date: Fri, 23 Jun 89 16:02:31 EMT Subject: Positions at Bergen Scientific Centre BERGEN SCIENTIFIC CENTRE - JOB OPPORTUNITIES Reservoir Modelling-Numerical Algorithms-Software Development Bergen Scientific Centre, IBM, is building up its research activity based on numerical oil reservoir modelling. This work involves the development of adaptive multigrid solvers for Navier Stokes flows and the development of multigrid solvers for reservoir simulation. Current areas of interest include : automatic error estimation and grid refinement, parallelization on shared/distributed memory architectures and the treatment of complex geometries. The orientation of this work is with a view to using parallel/vector computer architectures. We are looking for scientist(s) interested in either of the following areas: APPLIED MULTIGRID/DOMAIN DECOMPOSITION METHODS STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS as related to oil reservoir simulation. Appointments in these areas will be for a period of one or two years. Bergen provides a pleasant environment in the heart of the Western Fjords of Norway with excellent opportunities for outdoor pursuits especially skiing, and water-sports. The centre is English speaking and provides a friendly and flexible environment for scientists of many different backgrounds. Contact Chris Thompson at either of the electronic mail addresses: THOMPSON AT KRYPTON.BSC.NO FSCCT AT NOBERGEN.BITNET or Aladin Kamel: ALADIN AT KRYPTON.BSC.NO FSCAK AT NOBERGEN.BITNET or Patrick Gaffney: PAT AT KRYPTON.BSC.NO FSCPG AT NOBERGEN.BITNET ------------------------------ From: John R. Rice Date: Fri, 23 Jun 89 12:31:24 EST Subject: Vector/Parallel Polynomial Arithmetic Vector/Parallel Polynomial Arithmetic Does anyone know of software or algorithm implementations of polynomial arithmetic for vector or parallel machines? We are interested in Univariate & Sparse Multivariate Polynomials and the operations: Multiplication Division Evaluation at multiple points Interpolation Residue computation Reply to John R. Rice jrr&cs.purdue.edu 317-494-6003 C. Bajaj bajaj@cs.purdue.edu 317-494-6531 ------------------------------ From: Jon Claerbout Date: 25 Jun 89 02:01:53 GMT Subject: Scientific programming in C++ Scientific programming in C++ ? ABSTRACT: I converted some simple scientific Fortran/Ratfor programs into C++ to see if they would look suitable for a textbook such as my last book "Imaging the Earth's Interior". I conclude C++ is about as good as fortran-ratfor. Unfortunately, mixing Fortran with C++ ranges from undocumented to impossible. BOOK REPORT The new Lippman C++ book looks like a replacement for the Stroustrup book since it fully describes the new AT&T version 2.0. Pedagogically it is a big improvement too. Since both Stroustrup and Lippman describe both C and C++ I infer they mean eventually to replace C by C++ (else why the 100+ extra pages to explain C which K&R already do beautifully)? A section called "linkage to other languages" mentions C but not Fortran. PROGRAMS We couldn't link gnu C++ mains to fortran subroutines. I converted some simple fortran scientific programs to a C++ style designed to please fortran users and I posted them to [the UNIX network newsgroup] comp.lang.fortran. Jon Claerbout Dept. of Geophysics Stanford University ------------------------------ From: Cleve Moler Date: Sun Jun 25 12:43:27 PDT 1989 Subject: No NA News Digest Next Week I'll be out of town next weekend, and things are pretty slow anyway, so it will be two weeks until the next NA News Digest. Happy Fourth of July. --Cleve ------------------------------ End of NA Digest ************************** -------