HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.math.num-analysis
Subject: Re: fitting circle to data points on small arc
From: pfennige@uni2a.unige.ch
Date: 13 Apr 92 18:57:46 +0200
Distribution: na
Organization: University of Geneva, Switzerland

Concerning fitting a circle to data points, recently 
	ritley@uimrl7.mrl.uiuc.edu 
posted a message with the program FELLIPSE that fits an ellipse.
Instead of posting again the program FCIRCLE let me just mention that 
a small modification to FELLIPSE fits circles by minimizing 
        sum( (X_i^2+Y_i^2 + d X_i + e Y_i + f)^2 )
The result is invariant by translation & rotation of the data points.

The following construction of the data matrix in FELLIPSE
> C     Building the matrices A and B 
> C
>       DO 10 I = 1, N
>         A(I,1) = X(I)**2-Y(I)**2
>         A(I,2) = X(I)*Y(I)
>         A(I,3) = X(I)
>         A(I,4) = Y(I)
>         A(I,5) = 1. 
>    10   B(I) = -(X(I)**2+Y(I)**2)
> C

should be replaced by 

> C     Building the matrices A and B 
> C
>       DO 10 I = 1, N
>         A(I,1) = X(I)
>         A(I,2) = Y(I)
>         A(I,3) = 1. 
>    10   B(I) = -(X(I)**2+Y(I)**2)

and B(1), B(2), and B(3) are d, e, and f after the call to HFTI.

I can email FCIRCLE if this is not clear enough. 

	Daniel Pfenniger 

Newsgroups: sci.math.num-analysis
From: dow@nova2.stanford.edu (Keith Dow)
Subject:  Non-linear optimization
Organization: Stanford University
Date: Fri, 17 Apr 1992 03:34:45 GMT


	I just read the book "Large-Scale Numerical 
Optimization" edited by Coleman and Li.  It is from
a conference held in 1989.  

Anyway, have things changed much since then?  Specificly
the paper by Jorge Nocedal recommends the "Polak and Ribiere"
conjugate method.  Also he recomends the limited memory
"BFGS" method.  These can be found essentially in Numerical
Recipes.  Hasn't much changed since Numerical Recipes was 
published?
Newsgroups: sci.math.num-analysis
From: ritley@uimrl7.mrl.uiuc.edu ()
Subject: Re: wavelet code?
Reply-To: ritley@uiucmrl.bitnet ()
Organization: Materials Research Lab
Distribution: na
Date: Tue, 14 Apr 1992 14:33:04 GMT

In article <32822@darkstar.ucsc.edu>, tomas@cats.ucsc.edu (Thomas Joseph
Avila) writes:

|>   Hi, does anyone know where I could find code (preferably in C) to
|>perform wavelet analysis AND synthesis (reconstruction) on a time
|>series.  I have been trying to code this myself but the reconstructions
|>aren't correct, so I have a bug somewhere.  Actually code that
|>just does wavelet analysis would be helpful also.

The following article was posted to a newsgroup (possibly this one) a
few weeks ago.
My guess is that the code is in Fortran rather than C.  I am not sure
this will
solve your problem (viz. synthesis), but maybe it will help.

========================cut here==================================
Preprints and software are available by anonymous ftp from the
Yale Mathematics Department computer ceres.math.yale.edu[130.132.23.22],
in pub/wavelets and pub/software.

epic is pyramid wavelet coder. (For source code, see question 3 in part one).

Bill Press of Harvard/CfA has made some things available for anonymous
ftp on site is 128.103.40.79, directory /pub. There is a short TeX
article on wavelet theory (wavelet.tex, to be included in a future
edition of Numerical Recipes), some sample wavelet code (wavelet.f, in
FORTRAN - sigh), and a beta version of an astronomical image
compression program which he is currently developing (FITS format data
files only, in fitspress08.tar.Z).
From: keith@euler.tv.tek.com (Keith Slavin)
Newsgroups: sci.math.num-analysis
Subject: In-situ 2-d non-square matrix transposition
Keywords: matrix transposition
Date: 9 Apr 92 17:16:23 GMT
Organization: Tektronix TV Products

Does anyone have an algorithm for IN-SITU transposition of a 2-d NON-SQUARE
matrix stored in a linear address space:

source memory location = source width * i + j,

move data to:

destination memory location = source height * j + i

(note: source height = destination width)

without requiring allocation of extra memory - the matrix is large
and I don't have much memory left.

Speed is not too much of an issue. I have found simple coordinate
transformation sequences which work for certain values of width and height,
but in many cases, these transformations produce closed sequences which are
only a subset of the total coordinate space, and a search (analogous to a
sieve) is required to complete the process. The sieve requires extra memory.

Is it even possible in the general case?

Thanks,

Keith Slavin
From: nicks@research.nj.nec.com (Nicholas Socci)
Newsgroups: sci.math.num-analysis
Subject: Tchebyshev Polynomials
Date: 17 Apr 92 19:32:24 GMT
Organization: NEC Research Institute
Originator: nicks@iris37.nj.nec.com


I am currently doing some numerical work using Tchebyshev polynomials to
approximate functions and I was wonder if anyone could provide me with
sources of information, tips, potential problems, etc on calculating 
the coefficients and evaluating them. In particular what are the
potential numerical problems (roundoff I  would imagine) in evaluating
polynomials with large powers. 

Thanks in advance

nick socci

-- 
-------------------------------------------------------------------------------
Nicholas D. Socci                  | Phone: (609) 951-2668
NEC Research Institute (Room 1B10) | Fax  : (609) 951-2496
4 Independence Way                 | Email: nicks@research.nj.nec.com 
Newsgroups: sci.math.num-analysis
From: burkhard@software.org (Neil Burkhard)
Subject: Code for FFT
Organization: Software Productivity Consortium, Herndon, Virginia
Distribution: usa
Date: Tue, 14 Apr 1992 13:01:42 GMT

I looking for FTPable code (Pascal, C, Fortran, etc). to do 
fast Fourier transforms (either real or integer). Are there
places you can point me to to find this? Or instead, is somebody
willing to e-mail a copy? Please respond to my e-mail address
below. Thanks.

---------------------------------------------------------------
Neil Burkhard                        Internet:  burkhard@software.org
Software Productivity Consortium     Phone:     703-742-7154
2214 Rock Hill Road                  
Herndon, VA  22070

"Just when you think you're on easy street, someone rips up
 the pavement"
From: roberto@cernvax.cern.ch (roberto bagnara)
Newsgroups: sci.math.num-analysis
Subject: Numerical analysis newsletters?
Date: 16 Apr 92 08:53:53 GMT
Organization: CERN, Geneva, Switzerland


Hi all,

    while studying for an elementary course in numerical analysis
I've found a nice unified proof for the convergence of both the
Jacobi and Gauss-Seidel methods for solving systems of linear equations
under the following conditions:

    a) strict diagonal predominance (by rows or by columns);
    b) non-strict diagonal predominance (by rows or by columns)
       and irreducibility.

    These results are obviously known to everybody, but the proof
I've found is very simple and (I believe) elegant. At least it is
much more simple and elegant than the disaggregated proofs I've
found in my textbook and a couple of others I've consulted (it
is *one* proof, and it is based on spectral considerations rather
than on low-level details).
I don't know if the proof is original and, even if it is, I think
that it's main importance could be for teaching purposes. A couple
of mathematicians, friends of mine, agree on that.

    The question is the following: is there any numerical analysis
journal/newsletter publishing also short-notes/letters that
(after checking for originality) could publish this proof?
If so would send me their address?

Please respond by EMail. Thanks in advance
                                            Roberto
Newsgroups: sci.math.num-analysis
From: johnson@horta.rice.edu (Bruce Johnson)
Subject: Re: absorbing boundary conditions for PDE's?
Organization: Rice University
Date: Wed, 15 Apr 1992 14:16:04 GMT

In article <renns.703315913@sfu.ca> renns@fraser.sfu.ca (R Enns) writes:
>
>Does anyone have any experience with absorbing boundary conditions for PDE's?
>I am solving the generalized nonlinear Schroedinger equation: 
>
>         2i E    +   E    +    E    +    E     +  f(I=|E|^2) E  =  0
>             t        xx        yy        zz
>
>using the split-step Fourier method (SSFM) on a 128^3 mesh.  The interesting
>physics is occurring at the center of my lattice and I would like to absorb
>as much as possible of whatever hits the boundaries.  My pedestrian experiments
>with various boundary dampings simply create near total reflections.
>
>Any advice is sincerely appreciated.  Is 5-10% reflection achievable without
>much effort?
> 
>
>-- 
>
>Darran Edmundson
>darran@chaos.phys.sfu.ca

There are a couple of approaches that have been used in the chemistry
literature in the recent past (Journal of Chemical Physics).  I don't
have the specific references here, but can point out the years, anyway.
Back in ca. 1984, Kosloff and Cerjan used an exponentially decreasing
attenuator (one can use any smooth window function) placed on the last
several points of the relevant edge of the grid.  Empirically, they
found that 14-20 grid points were needed in order to avoid reflections.

Ca. 1988, Alvarellos and Metiu developed a variant that gracefully
bleeds off the wave function leaving the grid, propagating this portion
according to potential-less equations beyond the edge (which could be
done analytically in their initial application).

Somewhere in the time since then (1989-1990), Neuhauser and colleagues
have used a complex optical potential placed outside of the region of
the interesting physics in order to absorb the wave function.  I
believe this additional potential varies linearly with distance, but
I heard W. H. Miller contend at a conference a couple weeks ago that
there were some potential advantages (sorry) to nonlinear variation
with distance (not sure if this is published outside of the conference
proceedings).  One of my neighbors (D. J. Kouri at University of
Houston) is actively exploring this business also.

Bruce Johnson
From: robeson@ravel.udel.edu (Scott M Robeson)
Newsgroups: sci.math.num-analysis
Subject: Re: Matlab primer needed.
Date: 15 Apr 92 13:04:39 GMT
Distribution: na
Organization: University of Delaware

In article <sdd7cINN9hf@agate.berkeley.edu> pous@diva.Berkeley.EDU (Rafael Pous) writes:
...
>Does anybody have a Matlab primer that I could distribute to my students?
...

Check out the chapter on Matlab in 

Coleman, T.F. and C. Van Loan (1988) Handbook for Matrix
  Computations, Frontiers in Applied Mathematics Vol.4,
  SIAM, Philadelphia.

I found this to be a very concise and useful introduction
to the basic Matlab commands.

-- 
Scott Robeson            |   Internet:  robeson@brahms.udel.edu
Department of Geography  |   Bitnet:     geo24674@udelvm.bitnet
University of Delaware   |   Phone:                302-831-8678
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
From: Helgi.Hjalmarsson@cs.cmu.edu
Newsgroups: sci.math.num-analysis
Subject: Arbitrary triangulated surfaces.
Date: 8 Apr 92 17:42:36 GMT
Organization: Carnegie Mellon, Pittsburgh, PA


Does anyone know of a method to transform an arbitrary triangulated
surface into a plane? (I am only considering simply connected surfaces).
Pointers to papers would be appreciated.  Note that for arbitrary
surfaces projection does not work in general and breaking the surface
into a set of curves (which then could be made isoparametric curves in
2D) which extend between two boundary points of the surface does also
not work in general. One can think of a mushroom shaped surface where
both of these method fail. 

Thanks in advance,
Helgi Hjalmarsson
From: falzon@faust.inria.fr (Frederic Falzon)
Newsgroups: sci.math.num-analysis
Subject: Eigenvalue,Eigenvector
Date: 10 Apr 92 15:18:44 GMT
Reply-To: falzon@sophia.inria.fr
Organization: Inria Sophia Antipolis


 Does anybody have the general forms of eigenvalues and eigenvectors of an NxN
 pseudo-tridiagonal matrix of the form :
 
 For example with N=4;
 

	[(1+1/a) -1/a       0         0 ]
  A = 	[-1/a    (1+2/a)  -1/a        0 ]
	[ 0       -1/a    (1+2/a)  -1/a ]
	[ 0         0      -1/a  (1+1/a)] 

 Thanks in advance.


      Fred.
-----------------------------------------------------------------------------------------
From: jeff@mozart.helios.nd.edu (Jeff Kantor)
Newsgroups: sci.math.num-analysis
Subject: Re: Matlab primer needed.
Date: 15 Apr 92 14:29:45 GMT
Article-I.D.: news.1992Apr15.142945.29694
Distribution: na
Organization: University of Notre Dame, Notre Dame

In article <18759@ravel.udel.edu> robeson@ravel.udel.edu (Scott M Robeson) writes:
>In article <sdd7cINN9hf@agate.berkeley.edu> pous@diva.Berkeley.EDU (Rafael Pous) writes:
>...
>>Does anybody have a Matlab primer that I could distribute to my students?
>...
>
>Check out the chapter on Matlab in 
>
>Coleman, T.F. and C. Van Loan (1988) Handbook for Matrix
>  Computations, Frontiers in Applied Mathematics Vol.4,
>  SIAM, Philadelphia.


Just a second, guys. I'm not sure you want to be handing out photocopies
of a book chapter to all students in a class. Doesn't that violate
copyrights?    

There are alternatives. First off, Prentice-Hall is publishing a
student edition of matlab. The manual is quite good and available
seperately for $30. Then there is the brief summary by Kurt Sigmon
(U. Florida) that is distributed through the Matlab Users Group. It;s
a plain TeX document.        

Jeff Kantor
Notre Dame
From: rabson@oxford.ac.uk (David Rabson)
Newsgroups: sci.math.num-analysis
Subject: sparse underdetermined linear eqn solver
Date: 15 Apr 92 14:58:15 GMT
Organization: Oxford University Computing Service, 13 Banbury Rd, Oxford, UK
Originator: rabson@black

Does anyone have any good suggestions for a solver of sparse *underdetermined*
linear equations?  I don't need the entire solution space; any old solution
will do.  I have about 1400 equations in about 2800 unknowns.  Right now,
I'm using a slight modification of the Numerical Recipes SPARSE() routine,
but the results are quite poor (that is, it returns an unacceptably large
RSQ).

David Rabson
Theoretical Physics, University of Oxford
From: slkqz@cc.usu.edu
Newsgroups: sci.math.num-analysis
Subject: Matlab or MathCAD
Date: 9 Apr 92 22:45:10 GMT
Article-I.D.: cc.1992Apr9.164510.54352
Organization: Utah State University

I need help in deciding which one is the best offer.
Matlab Student Version $50 or MathCAD $99 (Re. $495)

I have to select one of the offers because my financial limitation.
Would you give me some suggestions.

Thank in advance,

Donny.
-------------------------------------------------------------
Idris M. Kamil
UWRL-USU
Logan, UT 84322-8200        BITNET : SLKQZ@CC.USU.EDU
                            Internet : ikami@pub.uwrl.usu.edu 
-------------------------------------------------------------
From: wucm@mt.luth.se (Wu Changming)
Newsgroups: sci.math.num-analysis
Subject: Looking for Finite Element programs for beam structures
Date: 7 Apr 92 19:30:54 GMT
Reply-To: Wu Changming <wucm@gb.luth.se>
Organization: University of Lulea, Sweden
UUCP-Path: {uunet,mcvax}!sunic!mt.luth.se!wucm


Hi:

I am trying to write a finite element program for beam structures using 
MATLAB. The beam structure has spring support boundary conditions. If 
someone has written such kind of programs and give me the code, I am 
very appreciated.

If the code is in Fortran or Pascal, it is also welcome.

Thanks in advance

Changming
wucm@gb.luth.se
From: ratier@lio.laas.fr (Nicolas Ratier)
Newsgroups: sci.math.num-analysis
Subject: Determinant
Date: 7 Apr 92 15:30:15 GMT
Organization: LAAS-Centre National de la Recherche Scientifique Toulouse, France
Originator: ratier@lio


   I have to compute the determinant of a block pentadiagonal matrix, exactly
 a matrix look like :

              / A  B  C                 \
             |  B  A  B  C               |
             |  C  B  A  B  C            |
             |     C  B  A  B  C         |
             |        -------------      |
             |           -------------   |
             |           C  B  A  B  C   |
             |              C  B  A  B   |
              \                C  B  A  /

where    A is a pentadiagonal matrix
         B is a   tridiagonal matrix
         C is a      diagonal matrix

and besides A, B, C are commuting pairwise (i.e. AB = BA, AC = CA, BC = CB)


   In fact, it is easy to find a efficient method to compute the determinant
of the pentadiagonal matrix by Gauss elimination way. What i need is a formula
for computing the determinant of a block pentadiagonal matrix from the
determinant of each (commuting) element.


   Do you have an idea how to solve this problem ?


                Thank you for responding, (please email me)

                        Nicolas RATIER


   -------------------------------------
   |       L.A.A.S.   (France)         |
   |                                   |
   |                                   |
   | Nicolas RATIER                    |
   |                                   |
   | email : ratier@laas.laas.fr       |
   | Tel   : (33) 61 33 62 46          |
   | Fax   : (33) 61 33 62 08          |
   | Telex : LAASTSE 520930F           |
   -------------------------------------
Newsgroups: sci.math.num-analysis,comp.lang.c
From: simon@mmpe.mineral.ualberta.ca (Simon Tortike)
Subject: Re: Digital-age counterpart for Abramowitz/Stegun?
Organization: University Of Alberta, Edmonton Canada
Date: Mon, 6 Apr 1992 20:46:54 GMT

harper@kauri.vuw.ac.nz (John Harper) writes:

>Abramowitz & Stegun IS "digital-age". Read its preface. Funnily enough, it
>doesn't totally supersede Jahnke & Emde, the pre-computer equivalent. J&E 
>has more and better altitude charts for analytic functions, and is quicker 
>to use when you want to see if a given differential equation has solutions 
>involving Bessel functions. Both are (or were) published by Dover Books.

>John Harper Mathematics Dept. Victoria University Wellington New Zealand

Another useful (but too pricey) book in this category is "An Atlas of
Functions" by J. Spanier and K.B. Oldham, published 1987 by Hemisphere
Pub. Co. in N. America, Springer Verlag elsewhere.  There are no tables or
computer disks, but it discusses all the included functions extensively, with
approximations, uses, coloured diagrams, and pseudo-code programs with 
commentary.
--
Simon Tortike                       | tel     : 403/492-3338
Asst. Prof. of Petroleum Engg.      | fax     : 403/492-7219
Dept of Min-Met-Pet Engg.,          |
University of Alberta,              | Internet: simon@mmpe.mineral.ualberta.ca
Edmonton, AB, CANADA T6G 2G6.       |
From: luk@ohstpy.mps.ohio-state.edu
Newsgroups: sci.math.num-analysis
Subject: Partial Differential Equation
Date: 17 Apr 92 03:19:50 GMT

Not familiar with elliptic partial differential equation...wondered if 
there is code for solving eignevalue/eigenfunction of elliptic PDE. 

P[\phi(x,y)]=E \phi(x,y)   in the region 0<x<x0, and 0<y<y0. E is eignevalue 
with eigenfuction \phi(x,y). P differential operator defined by 

P=(\partial_{x,x} + \partial_{y,y})+ a*(x* \partial_{y} -y* \partial_{x})+
  b*(x**2+y**2)

where a, b are constant
with boundary condition \phi(x,y)=0 for x=0, x=x0, y=0, and y=y0.

Ideally, I am looking for exact solution. However, I am no longer optimistic 
there is exact solution. I also realize NAG lib(mark 13 version) has a general 
routine for solving elliptic PDE, but it does not solve the
eigenvalue/eigenfuntion problem...
Any help or suggestion...
 
Newsgroups: sci.math.num-analysis
From: renns@fraser.sfu.ca (R Enns)
Subject: absorbing boundary conditions for PDE's?
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Wed, 15 Apr 1992 05:31:53 GMT


Does anyone have any experience with absorbing boundary conditions for PDE's?
I am solving the generalized nonlinear Schroedinger equation: 

         2i E    +   E    +    E    +    E     +  f(I=|E|^2) E  =  0
             t        xx        yy        zz

using the split-step Fourier method (SSFM) on a 128^3 mesh.  The interesting
physics is occurring at the center of my lattice and I would like to absorb
as much as possible of whatever hits the boundaries.  My pedestrian experiments
with various boundary dampings simply create near total reflections.

Any advice is sincerely appreciated.  Is 5-10% reflection achievable without
much effort?
 

-- 

Darran Edmundson
darran@chaos.phys.sfu.ca
Xref: sparky sci.math.num-analysis:1479 comp.lang.c++:6873
From: paul@svl.cdc.com (Paul Kohlmiller)
Newsgroups: sci.math.num-analysis,comp.lang.c++
Subject: Re: M++
Date: 17 Apr 92 05:22:44 GMT
Followup-To: sci.math.num-analysis

fink@think.com (Paul Fink) writes:

>I have heard of a mathematics library for C++ called M++.
>Does anyone have any information about it?
Sure. It is made by a company called Dyad software which is
located in Bellevue, Wa. It contains the linear algebra stuff you
expect and maybe more but I haven't dug into it very deep.
It runs on Unix, Mac and PCs and maybe more.
Here is some untested info re: how to get in touch with them:
UUNET: !pilchuck!smx!dyad
phone: 206-637-9426
fax:   206-637-9428
snail mail:
515 116th Ave. NE Suite 120
Bellevue,WA 98004
--
     // Paul H. Kohlmiller           //  "Cybers, Macs and Mips"         //
     // Control Data Corporation     // Internet: paul@robin.svl.cdc.com   //
     // All comments are strictly    // America Online: Paul CDC         //
     // my own.                      // Compuserve: 71170,2064           //
From: jd50@prism.gatech.EDU (Jim Dai)
Newsgroups: sci.math.num-analysis
Subject: C++ vector, matrix classes wanted
Date: 10 Apr 92 21:11:51 GMT
Organization: ISyE - Ga Tech

Does any one  have C++ vector and matrix classes 
that can be shared? email to dai@isye.gatech.edu

Thanks

-- 
Jim Dai 
School of Industrial/Systems Engineering
Georgia Institute of Technology, Atlanta Georgia, 30332
Internet: dai@isye.gatech.edu
Newsgroups: sci.math.num-analysis