HDTenEightyP/NetNews huggingface dataset:
From: kiss@cbnewsg.cb.att.com (john.c.kiss)
Newsgroups: sci.math.num-analysis
Subject: Software Package(s) for PDEs
Keywords: Numerical Techniques, PDEs, Fluid Dynamics
Date: 27 Jan 93 21:09:22 GMT
Distribution: usa
Organization: AT&T

Hello Netters,

I am looking for a software package (preferably in C)
that allows for the numerical solution of the Euler
equations (i.e., the Navier-Stokes equations with the
viscosity terms = 0).  The system is in 3-D (i.e., 
x,y,z coordinates plus time, t). I am contemplating
running this package either on PC or on a SUN Workstation.
Therefore, if executables are not available, I would
adapt source code to them.

Please respond to kiss@hogpa.ho.att.com.

Thank you very much in advance,

John C. Kiss
kiss@hogpa.ho.att.com
Newsgroups: sci.math.num-analysis
From: burr@seas.gwu.edu (Timothy J. Burr)
Subject: DFPMIN from num. recipes
Organization: George Washington University
Distribution: usa
Date: Mon, 25 Jan 1993 16:49:52 GMT

The FAQ questions mentions that this exists but does not say
how to get it.  Could someone let me know.  Thanks.

Tim

/*-----------------------------------------------------------------------*/
/* Tim Burr         burr@seas.gwu.edu  or  burr@enews.nrl.navy.mil	 */
/*"Essence is, that about a thing that makes that thing what it is"      */
/*-----------------------------------------------------------------------*/
Newsgroups: sci.math.num-analysis
From: dharry@cyclone.rice.edu (Dennis Harry)
Subject: Re: Numerical solution of ODEs with Bulirsch-Stoer extrapolation
Organization: Rice University
Date: Tue, 26 Jan 1993 18:54:14 GMT

In article <1993Jan20.054301.455@seas.smu.edu>, mhosea@seas.smu.edu (Mike Hosea) writes:
 
|> The reason extrapolation methods get very accurate results with large step
|> sizes is because they can use very high order approximations.  However,
|> my research has shown that when compared to conventional Runge-Kutta
|> and Adams methods of the same order, the extrapolation formulas are not
|> as efficient in terms of function evaluations per unit step.
                                                 ^^^^^^^^^^^^^
Yes, but the point is that they may take much larger steps.  Ideally,
their relative inefficiency per unit step is (more than) offset by having
to take fewer steps?

-- Dennis Harry (dharry@rice.edu) 
Newsgroups: sci.math.num-analysis
From: ramesh@MV3600.BMEN.TULANE.EDU
Subject: spherical harmonics
Reply-To: ramesh@MV3600.BMEN.TULANE.EDU
Organization: TULANE, BMEN, NEW ORLEANS, LA
Date: Thu, 21 Jan 1993 21:34:55 GMT
Nntp-Posting-Host-[nntpd-14052]: bpbme.bmen.tulane.edu

hi:

	does anyone know where fortran code for the spherical harmonics
        Ylm is available?

thanks:

my e-mail address is 
ramesh@mv3600.bmen.tulane.edu
From: scastill@nmsu.edu (Steve Castillo)
Newsgroups: sci.math.num-analysis
Subject: symbolic math package
Date: 26 Jan 93 16:10:11 GMT
Article-I.D.: tesla.SCASTILL.93Jan26091011
Distribution: sci.math.num-analysis
Organization: NMSU Computer Science


I am currently looking for a good symbolic math package for my 486 pc.
It appears that both Mathematica and Maple are very powerful and
verstatile packages that might serve my needs.  The heaviest use for
such a package is in the derivation in going from the governing
integral or differential equations for a fields problem to the finite
difference, finite element or boundary element code.  This includes
all the analytical work in defining basis functions, test functions,
integrations, etc.  Most of the work is for Cartesian, cylindrical and
spherical coordinate systems.  I would like to hear from other users
about the following:

1.  The adequacy of the package for integration and differentiation 
of functions involving
algebraic functions and combinations of algebraic functions with other
special functions such as trigonemetric, bessel, Legendre and Hermite
polynomials.

2.  What is the kind of performance I can expect for such a package
running on a 50 MHz 486 under windows and/or OS/2.

3.  Realistic memory and disk requirements for the package.

4.  Adequacy of the package for generating fortran 77 code.

Please email me to save bandwidth.  Thanks in advance for your
opinions.

--
*****************************************************************
Steve Castillo
New Mexico State University
Las Cruces, NM

scastill@nmsu.edu
(505)646-3214
Newsgroups: sci.math.num-analysis
From: mhosea@seas.smu.edu (Mike Hosea)
Subject: Re: Numerical solution of ODEs with Bulirsch-Stoer extrapolation
Organization: SMU - School of Engineering & Applied Science - Dallas
Date: Thu, 28 Jan 1993 17:32:03 GMT

In article <C1H5uF.5HC@rice.edu> dharry@cyclone.rice.edu (Dennis Harry) writes:
>In article <1993Jan20.054301.455@seas.smu.edu>, mhosea@seas.smu.edu (Mike Hosea) writes:
> 
>|> The reason extrapolation methods get very accurate results with large step
>|> sizes is because they can use very high order approximations.  However,
>|> my research has shown that when compared to conventional Runge-Kutta
>|> and Adams methods of the same order, the extrapolation formulas are not
>|> as efficient in terms of function evaluations per unit step.
>                                                 ^^^^^^^^^^^^^
>Yes, but the point is that they may take much larger steps.  Ideally,
>their relative inefficiency per unit step is (more than) offset by having
>to take fewer steps?

No, it's not.  Not when you consider the competition.  It is true that
an extrapolation code may perform better than a fixed order Runge-Kutta
code when the tolerance is very stringent, but this is only because they
can go to higher order.  However, like the extrapolation formulas, the
Adams-Moulton formulas are variable order, and at each order (especially
high orders) the Adams-Moulton formulas are much more efficient.  If you
compare the performances of codes you may not see this since the Adams
code might not attept to use the higher orders--this would have nothing
to do with the methods themselves.  Anyway, I am not arguing from intuition.
Check out the mathematics in my report or any reputable numerical
comparison like

  L.F. Shampine and L.S. Baca  1986  "Fixed versus variable order
  Runge-Kutta", ACM TOMS, 12, no.  pp. 1-23.
-- 
Regards,
Mike Hosea (mhosea@seas.smu.edu)
Newsgroups: sci.math.num-analysis
From: dim2@kimbark.uchicago.edu (Alexander Dimitrov)
Subject: Re: Displaying 4D data (nodal displacements)
Reply-To: dim2@midway.uchicago.edu
Organization: University of Chicago
Date: Thu, 21 Jan 1993 23:34:13 GMT

Mathematica Has a package that does 3D field plot. It draws little
arrows, indicating the direction of a field in space. That might help
you. The package is in the standard distribution.

-- 
____________________________________________________________________
Alexander Dimitrov		a-dimitrov@uchicago.edu  (Internet)
tel.(312) 667-1611	   or   a-dimitrov@uchicago      (Bitnet)
__________________
Newsgroups: sci.math.num-analysis
From: rcpshdb@dutrun2.tudelft.nl (Han de Bruijn)
Subject: Re: Theory about Fluid-Structure ?
Originator: rcpshdb@dutrun2.tudelft.nl
Reply-To: rcpshdb@dutrun2.tudelft.nl (Han de Bruijn)
Organization: Delft University of Technology
Date: Fri, 22 Jan 1993 10:23:44 GMT

In article <1993Jan21.131854@roper.mc.ti.com> W. Donald Rolph:
> I agree completely with Han.

Well, at least we come close.

> the problem is indeed tractable, ...

Theoretical yes, practical no. Even if it is possible, theoretically, to
couple the solid with the fluid equations, then it is still not possible,
in practice, to solve a true "demanding" Fluid-Structure application, due
to the amount of work involved. While carrying out the unification process,
attention must be given to: how to interface FV and FE practices, as they
are actually implemented today. (Mind that it is already difficult to build
a proper interface for different FEA packages!)

> Han you have brought up upwind differencing for the convective term before.
> I reference Zienkiewicz 1977 starting on page 633 where he discusses
> applying upwind differencing for the convective term using fea procedures.
> If these equations are consistent with your fv upwind differencing, ...

And, as we both agree upon, such interfacing problems do not seem to exist
for the diffusive part of the equations.

As far as I can see, FE shape function upwinding is _not_ consistent with
FV upwinding. So here remains work to be done. However, I think a far better
place to start is the "streamline upwind differencing" technique, currently
employed by FLOTRAN. The latter product is especially interesting, because
accompanying documents explicitly refer to FV techniques of Patankar et al.
But most of all, it is unified _commercially_ with a well known FEA vendor:
ANSYS. So there should be hope for practical Fluid-Structure calculations
in the near future. Unless they don't get the message ...

> If the above paragraph sustains critical review, then my position is an even
> more optimistic one than yours, that is to say yes we need a merging of the
> two techniques - I agree completely, but further that the math to merge the
> two techniques already exists.

I am a bit less optimistic concerning the "math that already exists":
IMHO a few pieces of the puzzle are still missing.

> ONE universal numerical method can be achieved today!

Sustained, anyway.
-- 
* Han de Bruijn; Applications&Graphics | "A little bit of Physics * No
* TUD Computing Centre; P.O. Box 354   | would be NO idleness in  * Oil
* 2600 AJ  Delft; The Netherlands.     | Mathematics" (HdB).      * for
* E-mail: Han.deBruijn@RC.TUDelft.NL --| Fax: +31 15 78 37 87 ----* Blood
From: CCB104@psuvm.psu.edu
Newsgroups: sci.math.num-analysis
Subject: Nonlin. Part. Diff. Eqs.; PLEASE SUGGEST HOW TO SOLVE!
Date: 27 Jan 93 00:43:43 GMT
Organization: Penn State University

Please, I need help---by way of even merely a suggestion as to what
"canned" FORTRAN or Mathematica software packages to use for numerical
integration---in solving the following system of nonlinear partial
differential equations. (Laplace transforms work nicely on systems like
this when they are linear. But this system is certainly not linear!)

(The following details are provided to show what *kind* of system of
differential equations are under consideration. For example, as far
as BOUNDARY CONDITIONS are concerned at *one* of the two boundary
points, the actual *values* of the functions or of their first partial
derivatives with respect to x are *not* given, just relations among
them at the point in question!)

Given that

     U = U(x,t)
     V = V(x,t)
     W = W(x,t)

and that "dot" and "prime" represent partial differentiation
with respect t and x, respectively,
     .
     U = a U'' + b U W + c V^2

     .
     V = A V'' - b U W - c V^2

     .
     W = B W'' + b U W + c V^2 + C W

where a, b, c, A, B, and C are constants,
subject to the

BOUNDARY CONDITIONS:

(1) at x = 0, t > 0:

     U' = - V' = W',
     i.e. U' + V' = 0 and V' + W' = 0
     and
     U/V = V/W = f(t) [i.e. a given function of t]

(2) at x = "infinity," t > 0:

     U = a given constant, <--------
     V = W = 0,                     |
                                    |
 and to the                         |
                                    |
INITIAL CONDITIONS:                 |
                                    |
(3) at t = 0, x > 0:                |
                                    |
     U = the same given constant ---
     V = W = 0

How, please, might this system of partial differential equations be
solved, presumably or hopefully using Laplace transforms, "canned"
FORTRAN subroutines (e.g. IMSL), Mathematica, MACSYMA, or whatever?

Surely I don't expect anyone to actually solve them, but *suggestions*
would be very much appreciated!

Thanks!!

Carey Briggs
Newsgroups: sci.math.num-analysis
From: dch@comlab.ox.ac.uk (David Handscomb)
Newsgroups: sci.math.num-analysis
Subject: Re: A postscript on domain decomposition.
Date: 26 Jan 93 10:03:56 GMT
Organization: Oxford University Computing Laboratory, UK
Originator: dch@nagp12.comlab

In article <1993Jan23.173616.29522@Princeton.EDU> rdbeckie@water.Princeton.EDU (Roger Beckie) writes:
>Much of the work on domain decomposition has been published in the
>proceedings of a series of special conferences.
>
>I believe there was a fourth conference in 1992. The proceedings should
>be available from SIAM.

There have been two more conferences, in 1990 and 1991; the proceedings of each were published
by SIAM in the following year (Proceedings in Applied Maths 51 (1991) and 55 (1992).
From: sramamoo@nyx.cs.du.edu (Darth Vader)
Subject: Re: Algorithm(s) need for Bessel functions
X-Disclaimer: Nyx is a public access Unix system run by the University
	of Denver for the Denver community.  The University has neither
	control over nor responsibility for the opinions of users.
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Thu, 28 Jan 93 17:45:07 GMT

Hi,
	I beleive there are some routines for bessel functions available
in the TOMS package. Try netlib@research.att.com for the list of
functions available in the TOMS package. You can send for index to the
machine or you can do an anon ftp to the site.

D.V
Newsgroups: sci.math.num-analysis
From: muyu@bow.Princeton.EDU (Muyu Guo)
Subject: C-code of shift-register random number generator wanted
Originator: news@nimaster
Organization: Princeton University
Date: Thu, 21 Jan 1993 23:20:01 GMT

The title says it. Any infomation on where to find them is also
greatly appreciated.  I am also interested in the parallel SIMD
version of it, if there are any. Thanks,

--
Examples* are like R127, R250 or R1279 etc.
*For example, R250 algorithm is just X_n = (X_{n-103).XOR.X_{n-250})

-- 
Muyu Guo
Newsgroups: sci.math.num-analysis
From: jesperse@nas.nasa.gov (Dennis Jespersen)
Subject: Least squares with inequality constraint
Organization: Computational Fluid Dynamics Branch, NASA Ames Research Center
Date: 21 Jan 93 14:32:26


Can someone suggest a reference for the least squares problem with
inequality constraint, e.g. minimize || Ax-b || subject to x>=0, where
A is an mxn matrix and the inequality constraint on x is understood to
be component-wise.  I am mainly interested in the case m<n.  Thanks in
advance.
--
Dennis Jespersen                Voice: (415) 604-6742                      
MS 202A-2		        FAX:   (415) 604-1095                      
NASA Ames Research Center       email: jesperse@rft28.nas.nasa.gov         
Moffett Field, CA 94035-1000    We have met the enemy and he is us. -- Pogo
Newsgroups: sci.math.num-analysis
From: shaulz@jeremy.enet.dec.com ()
Subject: Help , Sparse matrix inversion
Keywords: matrix,sparse,inverse
Reply-To: shaulz@jeremy.enet.dec.com ()
Organization: Digital Equipment Corporation
Date: Thu, 21 Jan 1993 12:56:09 GMT



Hi!
I am looking for an efficient algorithms for finding
 the inverse of sparse matrix.
The matrix has the following structure :

 xxxxxx00000...00000xxxxxx0000...000 
 0xxxxxx00000...00000xxxxxx0000...00
 00xxxxxx00000...00000xxxxxx0000...0
 .                                 .
 .                                 .
 .                                 .
 xxxxxx00000...00000xxxxxx0000...000 
 0xxxxxx00000...00000xxxxxx0000...00
 00xxxxxx00000...00000xxxxxx0000...0

I looked in Numerical Recipes with no result.
I will appreciate any references to code/algorithms.

Thanks 
 Shaul.
Newsgroups: sci.math.num-analysis
From: chu@csi.jpl.nasa.gov (Chester Chu)
Subject: curve-fit to a gaussian distribution
Originator: chu@melody
Organization: Jet Propulsion Laboratory, Pasadena, CA
Date: Mon, 25 Jan 1993 18:46:52 GMT



Does any one have experience in fitting random data to a Gaussian distribution?
A straightforward way is to formulate the problem as a NLS problem and to solve
for the mean and the variance.  Can anyone comment on the speed of convergence
or suggest other method(s) to solve this curve fitting problem.

Please email your comment to chu@csi.jpl.nasa.gov.  Thanks!
-- 
chu@csi.jpl.nasa.gov
Newsgroups: sci.math.num-analysis
From: cbbrowne@csi.uottawa.ca (Christopher Browne)
Subject: Re: HELP!!(Cholesky Decompsition for negative-definite matrix ???)
Organization: Dept. of Computer Science, University of Ottawa
Date: Sat, 23 Jan 93 04:00:09 GMT

In article <1993Jan22.090701.11440@vax.oxford.ac.uk> nagrwb@vax.oxford.ac.uk writes:
>In article <20JAN199313260117@envmsa.eas.asu.edu>, sychen@envmsa.eas.asu.edu (Chen, Shen Yeh) writes:
>> 
>>    I need to solve a linear system equation. In fact, that's the stiffness
>>  matrix [K] from finite element method. The system is like :
>>  [K]*{U}={P}.  where [K](nxn)
>> 
>>    [K] IS ALWAYS SYMETRIC, but not necessarily positive-definite. If it is
>>  singular, we think this system to be unstable. Because of the symetry, I
>>  always use Cholesky Decompsition to reduce the size of [K]. However, now
>>  I have some situation that [K] is negative-definite but I still have to
>>  solve the equation. I have not try Gauss method yet, however.
>> 
>You could try the Bunch-Kaufmann method - see Golub + Van Loan, Matrix
>Computations Sec 4.4, 2nd edition, 1989 Software is available in LAPACK
>on netlib.

Another useful reference is: 
@book{Gill1981,
        title="Practical Optimization",
        author="Gill, Philip E. and Walter Murray and Margaret H. Wright",
        year=1981,
        publisher="Academic Press"}

It describes a modified Cholesky decomposition that attempts to
minimize the error due to ill-conditioning.

I didn't bring it home this weekend, so I can't type anything in on
this.

I'm not aware of the availability of SPECIFIC code for this, but
wouldn't be surprised if there's something floating around in FORTRAN.

I've got some C code by Ajay Shah that does normal Cholesky, but
that's probably not what you want :-(.

-- 
Christopher Browne                |     PGP 2.0 key available
cbbrowne@csi.uottawa.ca           |======================================
University of Ottawa              | Genius may have its limitations, but
Master of System Science Program  | stupidity is not thus handicapped.
From: eran@fnth06 (Eran Yehudai)
Newsgroups: sci.math.num-analysis
Subject: Partial Differential Equation   routine
Date: 26 Jan 93 23:21:26 GMT
Organization: FERMILAB, Batavia, IL
NNTP-Posting-Host: fnth06.fnal.gov
X-Newsreader: Tin 1.1 PL5

I'm interested in getting a C or Fortran program to solve
parabolic PDEs in 3 space and 1 time dimension. I have
something called vecfem from Germany, but it's rather
hard to use. I need to be able to specify spherically
symmetric initial conditions - some routine will only
let me specify the initial data on a cube and this will
not do for my problem. 

Thanks very much.

bob
Newsgroups: sci.math.num-analysis
From: ruediger@leland.Stanford.EDU (ruediger dung)
Subject: roots of a function f: C x R --> C
Organization: DSG, Stanford University, CA 94305, USA
Date: Fri, 22 Jan 93 21:59:03 GMT

Hi,
does anybody know where I can find a Fortran subroutine
which calculates complex roots of a function
f: C x R --> C ? 
Any comment is appreciated.
ruediger  (ruediger@bigbang.stanford.edu)
Xref: sparky sci.math.num-analysis:3954 comp.lang.pascal:8489
From: hgg@ecs.soton.ac.uk (Harald Geiger)
Newsgroups: sci.math.num-analysis,comp.lang.pascal
Subject: Pascal routine for Hilbert Transform
Date: 24 Jan 93 15:10:01 GMT

A friend of mine is looking for a Pascal routine to handle a Hilbert
transform.
Can anybody help?

Thanks,
                                      Harald


Harald Geiger
hgg@ecs.soton.ac.uk
From: cosc18or@menudo.uh.edu (C. James)
Newsgroups: sci.math.num-analysis
Subject: Acceleration of convergence of vector sequences
Date: 21 Jan 1993 17:45:09 -0600
Organization: University of Houston
Distribution: inet
Expires: 21 Feb 1993
NNTP-Posting-Host: menudo.uh.edu
Summary: Recent articles or books on the above topic

If anyone knows of recent (>1988) journal surveys or textbooks
besides a 1988 book called Sequence Transformations, I'd appreciate
suggestions. I'm interested in methods proven to be superior in some
way to Steffensen's method.  My e-mail address is cosc18or@cs.uh.edu.
From: stewart@cs.umd.edu (G. W. Stewart)
Newsgroups: sci.math.num-analysis
Subject: Re: Condition Number Estimation and Column Selection
Date: 22 Jan 93 05:25:11 GMT
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742


  In article <C14IEJ.343.1@cs.cmu.edu> bs36+@EDRC.CMU.EDU (Boyd T
  Safrit) writes:

  I have been working with an equation solver with the
  idea of adding in the capability of condition number estimation.  My
  problem is this: I usually have a set of m equations in n variables,
  where n > m.  The remaining variables are "fixed" by the user.  We
  have had problems with some of the systems being ill conditioned. One
  of the cures we have identified is for the user to pick new degrees of
  freedom, or swapping some of the fixed variables in and some of the
  unfixed variables out of the factorization (we use something like
  Gaussian, but are looking at others.)  There are articles on
  incremental estimation that mention applications te kinds of problems.
  I would like to be able to give the user the proper set of variables
  to swap in and out, with the idea of decreasing the conditioning of
  the resulting system.  Does anyone have any information on this kind
  of problem?  Thanks in advance.  Boyd Safrit

The problem of variable selection was once a hot topic in statistics,
though the case considered was $m>n$; i.e., regression.  However,
for your case a QR~decomposition with column pivoting should be
adequate.  The LINPACK routines sqrdc and sqrsl should suit your
application.

Pete Stewart
From: mch@anu.edu.au (Mick Cardew-Hall)
Newsgroups: sci.math.num-analysis
Subject: Manufacturing Process Modelling
Date: 22 Jan 1993 05:29:49 GMT
Organization: Interdisciplinary Engineering Program, ANU, Australia
Distribution: world
Reply-To: mch@anu.edu.au
NNTP-Posting-Host: 150.203.45.16


HI

I have just arrived in Australia from the UK. I'm particularly interested in finding out
who is interested in the area of  modelling of manufacturing processes, particularly
casting and forging and in particular within Australia. 

I have a fair idea of what is going on in the UK , Europe and bits of the US but I want to
hear from ANYBODY ANYWHERE who has an interest.

I'll compile a list and mail it to those that drop me a line.


Thanks 


Mick Cardew-Hall
Engineering Program
Australian National University
GPO Box 4
Canberra
ACT
AUSTRALIA

Tel:   06-2490330
fax:   06-2490506
email: mch@faceng.anu.edu.au


Newsgroups: sci.math.num-analysis
From: mhosea@seas.smu.edu (Mike Hosea)
Subject: Re: need references for Runge-Kutta versus Multi-step ...
Keywords: Runge, Kutta, multistep, efficiency, ODE, PDE
Organization: SMU - School of Engineering & Applied Science - Dallas
Date: Tue, 26 Jan 1993 16:33:10 GMT

In article <1993Jan25.180439.26879@fys.ruu.nl> walsteyn@fys.ruu.nl (Fred Walsteijn) writes:
>Dear colleagues,
>
>I am looking for some recent references comparing
>the efficiencies of Runge-Kutta and Multistep methods.
>...                
>Can you give me some references where the efficiencies
>of those schemes are compared thoroughly ?
>

I have just written a paper with Larry Shampine on theoretical efficiency
comparisons of Runge-Kutta, multistep, and extrapolation methods.  As you
know, efficiency comparisons are ordinarily carried out as numerical case
studies, but these can be misleading because they are based on particular
implementations of the methods and a small set of test problems.  The 
method we present for theoretical efficiency comparisons overcomes these
concerns.  The paper has been submitted for publication, but you can get
the report version immediately.  Send me email at the address above or
at mhosea@sun.cis.smu.edu and ask for the SMU Math report #92-9

  Efficiency Comparisons of Methods for Integrating ODEs,

  by M.E. Hosea and L.F. Shampine.

-- 
Regards,
Mike Hosea (mhosea@seas.smu.edu)
Newsgroups: sci.math.num-analysis,sci.engr,sci.engr.mech