HDTenEightyP/NetNews huggingface dataset:
From: pushkar@bongo.cc.utexas.edu (pushkar tamhane)
Newsgroups: sci.math.num-analysis
Subject: Re: Commercial Finite Element Packages
Date: 12 Oct 92 20:40:11 GMT
Article-I.D.: ut-emx.81551
Reply-To: pushkar@bongo.cc.utexas.edu (pushkar tamhane)
Organization: The University of Texas at Austin, Austin TX
Originator: pushkar@bongo.cc.utexas.edu

I am posting this for someone who was not able to post on the net. I found
it very informative.

	Pushkar
-----------------------------original message-----------------------------

There are, as noted in the original posting, several commercially available 
Finite Element packages on the market.  In addition to ABAQUS, MSC/NASTRAN, 
and ANSYS, all of which are good packages, but with different capabilities, 
and markets, there are a considerable number of less well known packages.  
Some of these are specifically for the IBM-PC platform (such as ALGOR), and 
some have better dynamics capabilities, or buckling, or thermal capabilities 
than others.  There is even a P-version code out commercially, called RASNA, 
which is very good.

For the practitioner who needs to make a rational decision about what package 
to purchase, the first oder of business is deciding what type of problems 
will be solved with the package.  It is not really as easy as just deciding 
which is best, each of the packages has its good points and bad points.  
ABAQUS is an extremely good non-linear code, but is overkill for the more 
common linear elastic problems.  MSC/NASTRAN is very good at the airplane 
kinds of analysis, as one might guess (linear statics and dynamics).  ANSYS 
seems to be good for the power plant and automotive industries.  If a small 
commercial shop has AUTOCAD, then ALGOR might be the best answer.  

If I might make a suggestion, the Computers in Engineering Division of ASME 
puts on a conference each year, which deals in part with this issue.  There 
is also an exhibit with the conference with participation from most if not 
all of the larger commercial FE vendors.  I happen to be the Chairman of the 
conference this year, and would be delighted to see this whole issue brought 
up and fully discussed at the conference.  It will be in San Diego in August 
of 1993.  I can email anyone a copy of the call for papers that wants one, or 
I would be delighted to respond to any other requests for information.  
Alternatively, if anyone is interested, I have been in this business for a 
long time, and can help the uninitiated.  Those that have been around for 
some time I hope will understand that I am somewhat reticent to engage in 
what always tends to be a religious war.  That is, the choice of the "BEST" 
finite element package.  There is NO BEST ONE.  It all depends on the problem 
that is to be solved, and the analyst's abilities and proclivity.

Edward M. (Ned) Patton          npatton@swri.edu
Southwest Research Institute
San Antonio, TX  78228
Newsgroups: sci.math.num-analysis
From: andreas@veeble.han.sub.org (Andreas Dunker)
Subject: Tch. Rep vom Chalmers Univ.
Organization: Veeble-Mailbox Hannover
Date: Wed, 7 Oct 1992 16:59:41 GMT

I am looking for the Technical Report 1984-16 of the Chalmers
University of Technology. Can someone tell, how I can get this?

   ------------------------------------------------------------------------
   Andreas Dunker                                  andredu@hannover.by.byte
   In der Steinriede 7                           andreas@veeble.han.sub.org
   D-3000 Hannover 1
Newsgroups: sci.math.num-analysis
From: mek@jpl-devvax.jpl.nasa.gov (Mike Ketchmere)
Subject: Looking for tunneling algorithm implementation
Keywords: tunneling algorithm, global minimization
Organization: Jet Propulsion Laboratory (NASA)
Date: Tue, 13 Oct 1992 15:49:07 GMT

I'm looking for an implementation (preferably in C) of the tunneling algorithm
(originated by Levy and Montalvo I think) used to determine the global 
minimization of a function.  Would appreciate any information on where I might
find this code.  Thanks.

Mike
mek@thyme.jpl.nasa.gov
From: shimo@bcl.t.u-tokyo.ac.jp (Hidetoshi SHIMODAIRA)
Newsgroups: sci.math.num-analysis
Subject: How to compute tr(M^-1) ?
Date: 11 Oct 92 13:14:04 GMT
Reply-To: Hidetoshi SHIMODAIRA <shimo@bcl.t.u-tokyo.ac.jp>
Distribution: sci
Organization: Dept. of Math. Eng. and Information Physics, U of Tokyo


I have a question as how to compute trace of inverse of matrix M.

M is a real matrix, (not suppose symmetry), and eigen values within
zero to unity, that is, a1 >= a2 >=  an.
Some of ai's are zero, so I want to compute

tr(M^-) = 1/a1 + 1/a2 + ... + 1/ak,
where a1,...,ak are not zero and a_(k+1),...,an are zero.

Is there any elegant method to compute this?



 //\\\
  @ @     Hidetoshi SHIMODAIRA    <shimo@bcl.t.u-tokyo.ac.jp>
   O      Dept. of Math. Eng. & Info. Physics, Univ. of Tokyo
From: ss4i@kelvin.seas.Virginia.EDU (Sriram  Srinivasan)
Newsgroups: sci.math.num-analysis
Subject: Optimization question
Date: 8 Oct 92 18:37:04 GMT
Article-I.D.: murdoch.1992Oct8.183704.1866
Organization: University of Virginia
Originator: ss4i@kelvin.seas.Virginia.EDU

Hi,

 I had a (probably naive) question about an optimization problem that
I am trying to solve:

              min  F(x)      subject to
               x

                g_i[\lambda_i(x)] < 0,  i = 1,...,n

where \lambda_i is the i-th eigenvalue of some matrix. \lambda is a function
of x and the constraint g_i is a function of \lambda_i. The function F and
the constraints g are non-linear. When I compute the eigenvalues \lambda_i,
I sort the eigenvalues by the absolute value thus deciding the "ordering" of
the constraints. It is possible (I think so) that during the optimization
process, the "ordering" changes e.g. the 1st eigenvalue could become the
2nd and vice versa.

Now the questions:

1) does such a change in the ordering of the constraints
during the optimization, affect the process? adversely?

(I have tried this out on MATLAB using CONSTR.M and it seems to work most
of the times. The few times it did'nt work, it would say that it was
infeasible. Hence I was wondering about the effect of "ordering")

2) is there a neat way to "track" the eigenvalues such that the
"ordering" remains intact?

Thanks in advance for answers/pointers.

-sriram.

-------------------------------------------------------------------------------
Sriram Srinivasan                       ss4i@kelvin.seas.virginia.edu
Dept. of Mech. & Aero. Engg.
Univ. of Virginia.
-------------------------------------------------------------------------------
From: tzaki@haydn.helios.nd.edu
Newsgroups: sci.math.num-analysis
Subject: Public domain FE code
Date: 8 Oct 92 23:09:15 GMT
Distribution: usa
Organization: OUC, University of Notre Dame


Dear Netters,

Are there any public-domain finite-element codes written in 
FORTRAN to solve the two-dimensional Poissons equation. Any
pointers would be highly appreciated.

The code should be able to generate the triangular grid and
have a linear solver to solve the discretized equation. Are there
any anonymous FTP sites from where it can be downloaded. 

If this is an FAQ I apologise.

Prashant Mahasagar (tzaki@mozart.helios.nd.edu)
Peace Institute, University of Notre Dame 

To: 
Subject: Re: 
Newsgroups: 
Organization: OUC, University of Notre Dame
Cc: 
Bcc:
Organisation: Westfaelische Wilhelms-Universitaet, Muenster, Germany
Date: Thursday, 8 Oct 1992 15:19:55 MEZ
From: Martin Schluetz <SCHLUTZ@DMSWWU1A.UNI-MUENSTER.DE>
Newsgroups: sci.math.num-analysis
Subject:    nonlinear dynamic systems

Hi
I'm looking for books and other information about
nonlinear dynamic systems (nds) describing chemical reactions.
Does anybody know something about software to calculate
stability, bifurcations and periodic solutions of nds?

Please e-mail at: schlutz@dmswwu1a.uni-muenster.de
Newsgroups: sci.math.num-analysis
From: mjs@hubcap.clemson.edu (M. J. Saltzman)
Subject: Re: Network Flow Software
Keywords: software, assignment, scheduling
Organization: Clemson University, Clemson SC
Date: Thu, 15 Oct 1992 18:25:43 GMT

In article <1992Oct15.140016.7231@csi.uottawa.ca> cbbrowne@csi.uottawa.ca (Christopher Browne) writes:
>In article <1992Oct14.232927.24873@m.cs.uiuc.edu> joshi@m.cs.uiuc.edu (Anil Joshi) writes:
>>Try getting the code from netlib@ornl.com (I think the address is
                            ^^^^^^^^^^^^^^^
>>right). There are also a couple of public domain ones, 
>
>I couldn't find this site; this isn't the famous netlib -
>research.att.com.  I couldn't find anything quite relevant there.  (If

It's netlib@ornl.gov (Oak Ridge National Laboratory).
research.att.com is a mirror site.  I don't think the ornl site
supports ftp access, but it supports email service and a X-windows
interface called xnetlib.  Send the message "send index" to
netlib@ornl.gov for more information.  The nice thing about the xnetlib
server is that it's a very supportive interface for browsing, unlike 
FTP, where you really need to know exactly what you want.

(I didn't see anything relevant, but I didn't look that hard...)

>I was just not looking in the right directory, I'd love to be
>corrected.  It's always more useful to be given both the site name,
>and some reasonable pointer to a relevant subdirectory.)
>[...]
>Netflo, by Kennington & Helgason, is available at dimacs.rutgers.edu,
>in the directory /pub/netflow/mincost/solver1.
>
>I haven't been able to find a source for Relax III thus far.  Does
>anyone have any pointers to it?
>
>-- 
>Christopher Browne                |     PGP 2.0 key available
>cbbrowne@csi.uottawa.ca           | <-- Finger this account
>University of Ottawa              |
>Master of System Science Program  |


-- 
		Matthew Saltzman
		Clemson University Math Sciences
		mjs@clemson.edu
Newsgroups: sci.math.num-analysis
From: brucer@helios.physics.utoronto.ca (Bruce Sutherland)
Subject: bug in FFT Numerical Recipes in C?
Organization: University of Toronto Physics/Astronomy/CITA
Date: Fri, 16 Oct 1992 01:29:24 GMT

I'm hoping there are some people who have encountered a similar problem
to mine using the `Numerical Recipes in C' Fast Fourier Transform routine, four1.

In taking the fourier transform of the real function f(z)=z I get the
correct imaginary part of the fourier coefficients.  However, the real part,
which should be zero, evaluates to the same constant,C, for all non-zero
modes and zero for the zero mode.  If the domain size is L, this constant 
is L/(n-1) where n is the number of fourier modes.  It is as if the fft 
creates the shadow of a downwards shifted delta function, C (delta(x) -1).

I get the same results using both the realft and four1 routines.  What I want
to know is whether this result (C non-zero) is an artifact of the program
and if there is any way to eliminate it in a satisfactory manner?  

Thanks in advance,
Bruce Sutherland (brucer@helios.physics.utoronto.ca)
From: akyildiz@vax.oxford.ac.uk
Newsgroups: sci.math.num-analysis
Subject: Re: Root Solver Program
Date: 14 Oct 92 15:16:54 GMT
Organization: Oxford University VAX 6620

In article <1992Oct12.144802.1@cc.curtin.edu.au>, ssmithap@cc.curtin.edu.au writes:
> 
>   Hi!
> 
>   Could anyone tell me a name of a program for an MSDOS based machine
>   that can find the roots of an equation up to the nth order. (ideally
>   up to 10th order or better).  Where abouts would I be able to ftp 
>   such a program from.
> 
>   Could you please e-mail me your replies.
> 
>   Your help would be greatly appreciated
> 
>   Thanks
> 
>    Andrew
>    ssmithap@cc.curtin.edu.au
From: slzg4@cc.usu.edu
Newsgroups: sci.math.num-analysis
Subject: Wanted: 2-Point Boundary Problem Solver.
Date: 13 Oct 92 13:54:37 MDT
Organization: Utah State University

I am looking for a program or an algorithm to solve 2-point boundary
problems. Could someone send me a source code or give me a direction.
Thank you for your help.
S. Kuntanapreeda, U.S.U.
Newsgroups: sci.math.num-analysis
From: cbbrowne@csi.uottawa.ca (Christopher Browne)
Subject: Network Flow Software
Keywords: software, assignment, scheduling
Organization: Dept. of Computer Science, University of Ottawa
Date: Thu, 15 Oct 92 14:00:16 GMT

In article <1992Oct14.232927.24873@m.cs.uiuc.edu> joshi@m.cs.uiuc.edu (Anil Joshi) writes:
>Try getting the code from netlib@ornl.com (I think the address is
>right). There are also a couple of public domain ones, 

I couldn't find this site; this isn't the famous netlib -
research.att.com.  I couldn't find anything quite relevant there.  (If
I was just not looking in the right directory, I'd love to be
corrected.  It's always more useful to be given both the site name,
and some reasonable pointer to a relevant subdirectory.)

>one is called netflo written by Kennington and Helagason at Southern
>Methodist Univ and the other is called Relax III written by
>Bertsekas. I have implemented an Interior point path following version
>(algo by PM Vaidya) which is better than netflo and relax III only
>for very large problem sizes (# edges=>128,000) but hogs a lot more
>memory than the other two I mentioned.

Netflo, by Kennington & Helgason, is available at dimacs.rutgers.edu,
in the directory /pub/netflow/mincost/solver1.

I haven't been able to find a source for Relax III thus far.  Does
anyone have any pointers to it?

-- 
Christopher Browne                |     PGP 2.0 key available
cbbrowne@csi.uottawa.ca           | <-- Finger this account
University of Ottawa              |
Master of System Science Program  |
Newsgroups: sci.math
From: dzk@cs.brown.edu (Danny Keren)
Subject: Re: Do you know ?
Organization: Brown University Department of Computer Science
Date: Fri, 16 Oct 1992 15:11:09 GMT

kavuri@lips.ecn.purdue.edu (Surya N Kavuri ) writes:
#
#  Can you give me a function on an interval [a b] which is
#  not differentiable anywhere on that interval ?

To make the question interesting, you have to ask for the function
to be continuous (it is easy to construct functions which are
nowhere continuous and hence nowhere differentiable).

The famous example (by Weirstras I think) is

sin(x)+sin(2x)/2+sin(4x)/4+sin(8x)/8+sin(16x)/16+...

It is certainly continuous (by the M-test for instance) but
nowhere differentiable. 

As a matter of fact, *most* continuous functions (most in a
topological sense) are nowhere differentiable! See any good
tpology text (Willard for instance) for more; look for the
notion of category.

-Danny Keren.


Newsgroups: sci.math
From: tusk@daimi.aau.dk (Martin M|ller Pedersen)
Subject: Re: Magic Squares Orden 4 solved
Organization: DAIMI: Computer Science Department, Aarhus University, Denmark
Date: Fri, 16 Oct 92 00:06:59 GMT

A little about Magic Squares. 

  A standard magic square is a square array of positive integers from 1 through N^2, arranged 
so that the sum of every row, every column, and each of the two main diagonals is the same.
N is the "order" of the square. It is easy to see that the magic constant isthe sum of all the
numbers divided by N. The formulua is (1+2+3+4+...+N^2)/N = .5*(N^3+N)

  The trivial square of order 1 is simply the number 1, and of course it is unique. It is
equally trivial to prove that no order-2 square is possible.
  There is eight ways to arrange the digits 1 through 9 in an order-3 array that is magic.
It is traditional, however, not to count rotations and reflections. When they are excluded, the
order-3 square i unique.

  There are 880 magic squares ( excuding rotations and reflections ) of order 4. They were first
given by Bernard Frencle de Bessy in 1693.

  There are 275.305.224 magic square of order 5.

  Order 6 ???


Organization: Mathematics, Carnegie Mellon, Pittsburgh, PA
Newsgroups: sci.math
Date: Fri,  9 Oct 1992 16:58:00 -0400 
From: Oswald Wyler <ow0a+@andrew.cmu.edu>
Subject: Re: electronic math notation

TeX notation forces you to do more typing, but at least there is a reasonable
chance to be understood.  Some shortcuts are simply unacceptable.
Example xi.  I'll read this as a greek letter, preceding eta.
Example j=i+1.  Extremely dangerous; what do you do with a matrix with
entries aij?  I'd rather type x_{i+1} and a_{i,j}.
In any case, if your editor allows customizing (e.g. Emacs), you can easily
define a macro that types out {} for you and leaves you inside.
From: loeb@greco-prog.fr (Daniel LOEB)
Newsgroups: sci.math
Subject: Re: A proposal for a variant of chess
Date: 14 Oct 92 13:07:21 GMT
Reply-To: loeb@geocub.greco-prog.fr
Organization: GRECO Programmation du CNRS - Bordeaux,France

In article <1992Sep22.033321.14102@galois.mit.edu> you write:
>In article <1992Sep21.152035.12341@newstand.syr.edu> hgraber@lynx.cat.syr.edu (Harry Graber) writes:
>>     We wonder if this has been proposed before, and would like to hear
>>your opinions of this game. Suppose chess were played with three people
>>instead of two. The two who actually play the game decide upon the moves
>>they wish to make and submit them to the third person, who moves both
>>white's and black's men simultaneously. That is the only difference
>>between this game and the way chess is played now: white does not go
>>first.
>>
>>     There are two questions that come to mind right away...
>
>Most fundamentally, the game as described is not well-defined.  What
>if both players say that they want to move their piece to the same
>square?  What happens?

I noticed that the game is not completely defined. 
In my posting I ask for further information.
However, one could adopt some sort of simple conflict resolution.
(eg: the pieces "bounce" or both pieces are removed with no effect on
the square in question.) Some people might also like to prohibit
pieces (except the knights?) from moving through each other.  

>I have trouble seeing a way to resolve this without breaking the
>symmetry or introducing a very different element into the game.

These solutions are all symmetric, and they don't introduce any
fundamentally new elements into the game. 

>This is perhaps an interesting philosophical point: since real life goes on
>"concurrently" rather than players taking turns, in real life one
>will expect people's plans to "bump into each other" as I have described
>above.

"Concurrent" games are often called "matricial" games. There is a
great amount of literature on the subject.

Yours, Daniel Loeb				loeb@geocub.greco-prog.fr
HOME 	150, cours Victor-Hugo; Appt D45; 33000 Bordeaux France
WORK	LABRI; Universite de Bordeaux I; 33405 Talence Cedex France
PHONE(H)+(33) 56 31 48 26, (W)+(33) 56 84 69 05, (FAX) +(33) 56 84 66 69
-------------
Mankind faces a crossroads.  One path leads to despair and utter hopelessness,
the other to extinction.  Let us pray we choose correctly.  -- Woody Allen
-- 

Yours, Daniel Loeb				loeb@geocub.greco-prog.fr
HOME 	150, cours Victor-Hugo; Appt D45; 33000 Bordeaux France
WORK	LABRI; Universite de Bordeaux I; 33405 Talence Cedex France
From: kraai4712@iscsvax.uni.edu
Newsgroups: sci.math
Subject: Array Algebra
Date: 12 Oct 92 20:20:12 -0500
Organization: University of Northern Iowa

I would be happy to entertain any discussion about mathematics of arrays with
an arbitrary number of (integer) dimensions.  Can/has it been done?  Who,  in
what publication, when?  The obvious would be:
        scalars   zero dimensions
        vectors   one dimension
        matrices  two dimensions

I am very interested in this as I have found some convenient ways to represent
some combinatorial problems very nicely in this light.  Some relationships
acquire a very intuitive feel when the spatial relationships become tangible
through the use of such models.

aTdHvAaNnKcSe --jim kraai
Newsgroups: sci.math
From: rp@llex.ll.mit.edu ( Richard Pavelle)
Subject: Query about solution of an ODE at a point
Originator: rp@llex
Organization: MIT Lincoln Laboratory
Date: Fri, 16 Oct 92 10:25:21 GMT


I have a differential equation shown below where the subscripts are
derivatives. C, M, R and tf are constants. There are initial
conditions such that Y(0) and its derivatives are constant. 

The equation can be integrated once because the lhs is a perfect 
differential but that may not be relevant to my query.

                        Y       M Y
                         tt        t       M Y
               Y      + ---- + ------ + --------- = R
                ttt       C    tf - t           2
                                        (tf - t)

I am told there is a technique for solving an equation such as
this at a particular point, namely at t = tf, without actually
solving the differential equation. I would like to learn about
this technique and ask whether anyone can enlighten me. The
technique may rely upon Laplace transforms and may only be
applicable when M is an integer. 

Many thanks. 

 
Newsgroups: sci.math
From: bc205cs@opie.bgsu.edu
Subject: Zeno
Organization: Bowling Green State University
Date: Thu, 8 Oct 1992 04:03:40 GMT

Ok.  I don't read this newsgroup, but I know that if anyone can help me, it
will ne you guys.  If this problem has already been addressed in this
newsgroup, go ahead and flame me, but please give me some kind of answer.

Here's the problem:  My Calculus II professer was discussing the sum of the
infinite series 1/2 + 1/4 + 1/8, and so on.  He compared this to a famous
problem of Zeno's, in which zeno said that if you are trying to get from point
A to point B, and you go half of the remaining distance with each step, you
will never make it to point B.  This seems like common sense, because with
every step, you are not allowed to go more than half of the remaining distance.

Well, my professor showed us that the sum of this as the number of steps
approaches infinity is 1 -- To which my answer was, Great: you have to walk
_forever_ to make it to point B.  Then he explained, 'Let's say that you can
move 1 unit per minute.  The first step will take 1/2 minute, the next will
take 1/4 minute, and so on.  So, it will take 1 minute to get from point A to
point B!'

He used this to 'prove' Zenos paradox to be wrong -- you _can_ get from point A
to point B.  When I still questioned this, he reassured me, 'It took the
world's greatest minds centuries to figure this out, don't feel bad if you
don't understand it at first.'

Now here is my question:  The rule of the game is that you can only step half
of the remaining distance on each step.  Well, if you are standing at Point B,
that implies that you stepped onto point B.  If you stepped _onto_ point B,
then you broke the rule!  You were only supposed to step _halfway_ to point B. 
Therefore, Zeno's paradox holds, and the greatest minds are wrong.

So, What do you think?

--Joshua
jallen@andy.bgsu.edu or BC205CS@opie.bgsu.edu

Newsgroups: sci.math
From: thanasis@cs.columbia.edu (Thanasis Tsantilas)
Subject: Catalan NUmbers
Organization: Columbia University Department of Computer Science
Date: Wed, 7 Oct 1992 16:42:59 GMT


Is there a combinatorial ("bijective") way to prove that the 
Catalan numbers are equal to C(2n,n)/(n+1)? 
The answer looks simple, so I thought there must be something.
I'm only aware of the generating function solution of the recurrence.
Any pointers to books/articles are appreciated.

Thanasis Tsantilas
Columbia University
thanasis@cs.columbia.edu
From: wilson@web.ctron.com (David Wilson)
Newsgroups: sci.math
Subject: Polyhedron problem
Date: 9 Oct 92 19:59:19 GMT
Reply-To: wilson@web.ctron.com (David Wilson)
Organization: Cabletron Systems INc.



    Let P and Q be two polyhedra in Euclidean 3-space, with the following
    properties:

	P and Q have the same set of polygon faces.  For instance, P
	and Q might each have, say, 6 square and 8 equilateral
	triangular faces, of the same size.

	P and Q are distinct up to translation, rotation, and reflection.

    What, that, are the smallest number of faces P may have under each
    of the following conditions:

	1.  P and Q have distinct volume.

	2.  P and Q have distinct volume and regular polygon faces.

	3.  P and Q have equal volume.

	4.  P and Q have equal volume and regular polygon faces.


-- 
David W. Wilson (wilson@web.ctron.com)

Disclaimer: "Truth is just truth...You can't have opinions about truth."
- Peter Schikele, introduction to P.D.Q. Bach's oratorio "The Seasonings."