HDTenEightyP/NetNews huggingface dataset:
From: chuck@stratus.drexel.edu (Wombozni Klik)
Subject: Num Recipes errata?
Organization: Drexel University Department of Physics
Date: Fri, 8 Jan 1993 16:06:49 GMT
Distribution: sci.math.num-analysis
X-Posted-From: stratus.physics.drexel.edu
NNTP-Posting-Host: sol.ctr.columbia.edu


Is there a list of errata in the Numerical Recipes books (Fortran or
C)? Now that the 2nd edition of both are available, has someone
taken the time to collect errors in either texts? 
        
If you have a listing or know of an archive site, could you drop me a
line? 

Thanks,
        Chuck
--
Chuck Browne                            | Frisbeetarianism: The belief that  
Drexel University Department of Physics | when you die, your soul goes up
chuck@nimbus.physics.drexel.edu         | on the roof and gets stuck.
Newsgroups: sci.math.num-analysis
From: hrubin@pop.stat.purdue.edu (Herman Rubin)
Subject: Re: F-distribution
Organization: Purdue University Statistics Department
Date: Fri, 8 Jan 1993 17:49:40 GMT

In article <1993Jan7.224458.1@uwovax.uwo.ca> maxim@uwovax.uwo.ca writes:
>F-distribution

>I am looking for either a reference or some fortran source code
>that will allow me to calculate an f-value (percentile) given
>that the area (probability) and degrees of freedom DF1 and DF2
>are known.  There are numerous references that suggest how the
>area might be calculated given that the percentile is known, but
>I have yet to come across the opposite.

>The algorithm must be accurate to at least the fifth decimal place.
>Any suggestions would be greatly appreciated.

I cannot give you more than an algorithm, which I suggest should work
fairly quickly and will not require too much programming.

Since the density of the F distribution is quite simple, I suggest
that Newton's method be used to iterate.  To improve the performance,
I suggest that in the tails, the logarithm of the tail probability,
rather than the probability itself, be used.
-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: (317)494-6054
hrubin@snap.stat.purdue.edu (Internet, bitnet)  
{purdue,pur-ee}!snap.stat!hrubin(UUCP)
From: stewart@cs.umd.edu (G. W. Stewart)
Newsgroups: sci.math.num-analysis
Subject: Re: question about BALANC from EISPACK
Date: 8 Jan 93 12:15:07 GMT
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742

In article <1993Jan7.235543.25287@murdoch.acc.Virginia.EDU> ss4i@kelvin.seas.Virginia.EDU (Sriram  Srinivasan) writes:
#Hi,
#
#   I had the following question about the BALANC routine from EISPACK.
#
#   Given a matrix A, BALANC gives the balanced matrix
#
#          Ab = T*A*inv(T)
#
#   and also some information in the variables LOW, IGH, and SCALE which
#   determine the similarity transformation T.
#
#   Does anybody know how to construct a T explicity, for all A?
#
#   Thanks.                       
#
#   Sriram (spoiled by MATLAB)
#
#   (ss4i@kelvin.seas.virginia.edu)

The matrix T is constructed iteratively by balancing successively
each row and its corresponding column until the process converges.
Details can be found in

   @article{pare:69,
      author = "B. N. Parlett and C. Reinsch",
      year = "1969",
      title = "Balancing a Matrix for Calculation of Eigenvalues
               and Eigenvectors",
      journal = "Numerische Mathematik",
      volume = "13",
      pages = "293--304",
      kwds = "nla, eig, scaling, software"
   }

Pete Stewart
Organization: University of Illinois at Chicago
Date: Mon, 11 Jan 1993 17:08:31 CST
From: <U53644@uicvm.uic.edu>
Newsgroups: sci.math.num-analysis
Subject: Re: Robert Skeel, you suck.
 <1993Jan10.024855.3027@sifon.cc.mcgill.ca>

Mr. Marrett may wish to talk to the good folks at sci.logic about the
definition of an ad hominem. The previous poster did not seek to refute some
argument made by Prof. Skeel (who I don't know) by making a personal attack
(indeed, a logical error - though that is a valid approach when questioning the
truthfulness of a speaker). Rather, he offered his opinion as to the teaching
abilities of Prof. Skeel. Incidentally, Mr. Marrett may take note that his
response satisfies his own apparent misdefinition of 'ad hominem' (any critical
comment made about some one else ?).

It is a fact that there are some very good researchers who happen to be truly
awful teachers, and when our undergraduate students point out some candidates,
it is inappropriate for any of us to simply dismiss their criticism so lightly.
True enough, some of the complaints will come from poor students. But some will
be inspired by poor instructors. If the initial poster is honest in his
criticism of his instructor, he should be shown respect for the level of
courage shown here - the amount of damage an irritated faculty member can do to
an academic career is no secret. To seek to warn other students away from a bad
situation is a good thing to do - even if one doesn't sound very sophisticated
as one does so.


                                Joseph B. Dunphy
                                Graduate Student
                                    Mathematics - Indiana (on leave)
                                    Electrical Eng. - U.Illinois - Chicago
Newsgroups: sci.math.num-analysis
Subject: Eigenvectors of the sum of two symmetric matrices
From: mmt@ccu1.aukuni.ac.nz (Mark Thomson)
Date: Fri, 8 Jan 1993 00:19:59 GMT
Organization: University of Auckland, New Zealand.

If and A and B are two symmetric matrices, can anyone tell me whether it
is possible to relate the eigenvectors of (A+B) and their corresponding
eigenvalues to the eigenvectors and eigenvalues of A and B.

Any help appreciated.

Mark Thomson
University of Auckland.
From: kenny@castle.ed.ac.uk (K J MacDonald)
Newsgroups: sci.math.num-analysis
Subject: Greenfield Algorithm - What is it ?
Date: 6 Jan 93 10:29:06 GMT
Followup-To: kenny@ed.ac.uk
Organization: Edinburgh University

Dear Netters,
        I've got a piece of old fortran code (1971) which uses something
called the Greenfield Algorithm. Does anybody have any references to
this ?

Program: EMCAL
Synopsis: EMCAL calculates the Earth Response Functions for a 2 D
resistivity flat earth model. It builds a network of conductances, with
sources along the top and left, then solves for the voltages at each
node. This is where the Greenfield Algorithm comes in.

        Any help would be much apprecieted, PLEASE E-MAIL.

        Thanks, and Happy New Year,

                Kenny.

-----------------------------------------------------------
Kenneth MacDonald               E-mail kenny@castle.ed.ac.uk
Dept. of Geology & Geophysics
University of Edinburgh         Scotland
-----------------------------------------------------------
Newsgroups: sci.math.num-analysis
From: af235@yfn.ysu.edu (Bing Li)
Subject: MS/CFD JOB-SEEKING
Organization: Youngstown State University/Youngstown Free-Net
Date: Tue, 5 Jan 1993 17:12:26 GMT



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BING LI
From: laydin@solar.usc.edu (Levent Aydin)
Newsgroups: sci.math.num-analysis
Subject: Aproximating a messy product ...
Date: 4 Jan 1993 15:25:03 -0800
Organization: University of Southern California, Los Angeles, CA
Distribution: world
NNTP-Posting-Host: solar.usc.edu


	Hello everyone;
	I need to approximate a function given in terms of a product with a
simple function that I can deal with.The expression is as follows:

               n              /            \  
              __             |    x-m_i     | 
        g(x)= || 0.5*{ 1+ erf| -------------| }
              i=1            |  sqrt(2)*s_i | 
                              \            /  

	Here, m_i and s_i are two known sequences of non-zero real numbers.You 
can assume that the sequence m_i is a descending sequence and the value of s_i is
directly proportional to the value of m_i for each i.Also it is known that the
sequence m_i is such that it has only couple values which are significantly
larger than the rest of them.
	So far all I could figure was that the product is determined by the terms
with large values of m_i.I think that the product can be approximated by a
function similar to one of those terms, i.e. 0.5*{1+erf[(x-mo)/(sqrt(2)*so)]}.
The question is what are the optimum values for 'mo' and 'so'.
	Any input will be greatly appretiated.Thank you very much...


							L  E  V  E  N  T
P.S: The function erf(x) is the standard error function.
From: gaetz@head-cfa.harvard.edu (Terrance J. Gaetz)
Newsgroups: sci.math.num-analysis
Subject: Re: Fortran (was Re: "Minimize any function, as long as it is named FUNC")
Date: 11 Jan 93 00:03:42 GMT
Organization: Harvard-Smithsonian Center for Astrophysics

In article <C0npHD.830@news.cso.uiuc.edu> ercolessi@uimrl3.mrl.uiuc.edu (furio ercolessi) writes:
>
>* C code can be called from Fortran without troubles on most machines.
>  I knew about VSFR and have the code already, and will try it out soon.
>  Thanks for putting this code in the public domain.

What does VSFR do and where can it be obtained.  Thanks.

--
Terry Gaetz  --  gaetz@cfa.harvard.edu
Newsgroups: sci.math.num-analysis
From: a722756@roper.mc.ti.com (W. Donald Rolph)
Subject: Re: Condition Number
Originator: a722756@roper.mc.ti.com
Organization: Texas Instruments / Attleboro Mass / USA
Date: Tue, 12 Jan 1993 12:20:55 GMT


It is actually even more complex than just looking at the eignvalues.  ONe must
also examine whether the eigenvectors of the ill conditioning are being excited. 
It is a trivial example, but the largest positive definite ill conditioning on a
VAX in single precision is approximately 10E76.  The following matirx is the
worst case conditioning, but is highly stable during Gauss elimination:
 
                                 1.e38         0
              A         =                      
                                   0          1.e-38

This effect is particularly noticable in thin shell problems using dinite element
analysis, since the out of plane eigenvectors are not excited by in plane
bending, evne though the ill conditioning is very high (frequently on the order
of 10e9).
-- 

Regards.
 
Don Rolph  a722756@pan.mc.ti.com WD3 MS10-13 (508)-699-1263
From: jwe@bongo.cc.utexas.edu (John W. Eaton)
Newsgroups: sci.math.num-analysis
Subject: Re: Octave -- a high-level language for numerical computations
Date: 12 Jan 1993 10:07:12 GMT
Organization: The University of Texas at Austin, Austin TX
Distribution: inet
NNTP-Posting-Host: bongo.cc.utexas.edu

In article <1993Jan12.023957.14993@math.ucla.edu>
barry@arnold.math.ucla.edu (Barry Merriman) writes:
> In article <1iskmhINNokt@geraldo.cc.utexas.edu> jwe@che.utexas.edu
> (John W. Eaton) writes:
>
>> Octave is a high-level language, primarily intended for numerical
>> computations.  It provides a convenient command line interface for
>> solving linear and nonlinear problems numerically.
>
> What would be the advantage (besides $) of Octave over 
> Maple/Mathematica/MATLAB ?

Among other things, you get the source, so you can tinker with it if
you like.  If you make useful changes, you are free (and encouraged!)
to share them with everyone else.

In addition, there are a number of other minor features that I find
attractive:

  * You can choose whether you want assignment to an element of a
    matrix that is currently out of bounds to resize the matrix or
    produce a range error.

  * You can choose to have statements like
      clear a; for i = 1:5, a(i) = i; end
    produce column vectors or row vectors.

  * You can choose to disallow Fortran-style indexing of two
    dimensional matrices so that statements like
      a = [1,2;3,4]; a(2)
    produce errors.

  * Some Matlab functions (e.g., eye) will take negative arguments and
    treat them as 0.  Octave allows you to make this an error.

  * Some Matlab functions (e.g., eye) will take complex arguments and
    throw away the imaginary part.  Octave allows you to make this an
    error.

  * The ODE solver (LSODE) is built in to the interpreter, and there
    is a DAE solver (DASSL) that is also built in.

I also prefer the command line editing and history mechanism of
Octave, because it uses real Emacs-style keybindings and works just
like my shell (bash), and because the command history is saved between
sessions.

Octave doesn't have any symbolic capability (yet :-) so it is much
different from Maple or Mathematica.  Since Octave is intended for
numerical computations, one might find it to be more suitable for
those tasks than symbolic processors.

Whether these things are advantages is for you to decide :-).

--
Virtually all of the programs obtained by our sampling | John W. Eaton
procedure were written in FORTRAN.  -- Donald E. Knuth | jwe@che.utexas.edu
Newsgroups: sci.math.num-analysis
From: sanjay@eng.umd.edu (Kumarasamy Sanjay)
Subject: Re: Num Recipes errata?
Date: Sat, 09 Jan 93 18:08:10 GMT
Organization: Project GLUE, University of Maryland, College Park
Distribution: sci.math.num-analysis

Hi
  I don't whether this is in FAQ. Can somebody tell me
where I can find source code of Numerical Recipies in FORTRAN ?.

Tanx

Have fun

-sanjay
________________________________________________________________________
Sanjay Kumarasamy                |   
sanjay@eng.umd.edu               |                       
yajnas@wam.umd.edu               |    Thou art That
Voice:(H)301-345-0628            |
......(O)301-405-6872            |
------------------------------------------------------------------------
Newsgroups: sci.math.num-analysis
From: ercolessi@uimrl3.mrl.uiuc.edu (furio ercolessi)
Subject: "Minimize any function, as long as it is named FUNC"
Reply-To: ercolessi@uimrl3.mrl.uiuc.edu (furio ercolessi)
Organization: MRL - UIUC
Date: Fri, 8 Jan 1993 22:44:19 GMT

If you program in C please skip this post  :-)

In the Fortran edition of Numerical Recipes that I have (1989), they
have implemented multidimensional minimization routines that
can minimize any function, provided that it is called FUNC.
As they cheerfully say, "the situation is reminiscent of Henry
Ford's black automobile."

Now, I am bothered by this because I need to minimize many
different, unrelated functions in the same program.
Yes, I can code my FUNC with internal switches passed
via a common block.  Ugh! *Bleah* 
No, I want to fix this in a decent way.

They have done this stupid thing because of an interface routine
between multi- and one- dimensional minimization, called LINMIN
and minimizing the original function on a line between two points
in N-space. This is in turn done by using the ordinary one variable
optimization on a function they call F1DIM, which internally calls
the user's function, but it cannot gather its name from outside
because the argument list must contain only the coordinate and
nothing else in order to be used successfully by the lower layers.
And of course a function address cannot be placed into a common block.

Rats! It sounds that to fix this one has to redesign a lot of
things! At least one day's work :-).  I was wondering if any one
out there ran across this problem and fixed it already ...
Thanks
furio
--
Furio Ercolessi
Materials Research Laboratory           |   Intl School for Advanced Studies
Univ. of Illinois at Urbana-Champaign   |   Trieste, Italy
furio@uiuc.edu                          |   furio@sissa.it
Newsgroups: sci.math.num-analysis
From: endesa@lascar.puc.cl (Eduardo Lucero)
Subject: Re: Wanted: minimization routine
Organization: Club DataByte, Endesa
Distribution: inet
Date: Mon, 11 Jan 1993 04:59:54 GMT

In article <MATT.93Jan10152553@physics2.berkeley.edu> matt@physics2.berkeley.edu (Matt Austern) writes:
>From: matt@physics2.berkeley.edu (Matt Austern)
>Subject: Wanted: minimization routine
>Date: 10 Jan 93 15:25:53
>Does anybody out there have a recommendation for a minimization
>routine?  I'll be using it to minimize a function of two or three
>variables; the function is reasonably well behaved, but I am not able
>to calculate the derivatives very easily.
Try the Nelder's simplex method.
(Computer Journal, vol. 7, pp 308-313, 1964)
Eduardo Lucero
From: gbem@barbara.dist.unige.it (Giorgio Garziano)
Newsgroups: sci.math.num-analysis
Subject: "Eulero beam equation"
Date: 11 Jan 93 17:44:04 GMT
Distribution: eunet
Organization: DIST - Universita` di Genova
NNTP-Posting-Host: barbara.dist.unige.it


 


	What is the best way to solve the Eulero beam equation

		Wtt + Wxxxx = f(x,t)      x scalar

associated with appropriate initial and boundary conditions?
I will be grateful for any information forwarded to my email below.
Many thanks.

Giorgio Garziano

email : gbem@barbara.dist.unige.it
Newsgroups: sci.math.num-analysis
From: mhosea@seas.smu.edu (Mike Hosea)
Subject: Re: NAG routine D02BAF uses runge-kutta-MERSON ??
Keywords: Merson, nonlinear problems
Organization: SMU - School of Engineering & Applied Science - Dallas
Date: Tue, 5 Jan 1993 01:00:50 GMT

In article <1993Jan4.141352.5937@fys.ruu.nl> walsteyn@fys.ruu.nl (Fred Walsteijn) writes:
>I have just read that the NAG routine D02BAF is based on
>a Runge-Kutta-Merson embedded formula.
>Is it the same formula as mentioned in the books of
>Lambert (1991) and Butcher (1987) ?
>
>If it is, does that mean that its error truncation estimate
>is ``easily defeated'' (cite, as I remember it from one of
>the abovementioned books) ?
>The reason is that the ``high order'' component has a high
>(fifth) order of accuracy only for linear problems.
>It cannot have fifth order of accuracy for all (e.g. nonlinear) problems
>as it has only five stages (Butcher, 1987).
>

I believe the formulas are the same, though it would be easy enough
to check the NAG documentation to find out.  Shampine showed that 
Merson's pair for general non-linear problems can be viewed as a (3,4) 
pair (i.e. embedded formulas of orders 3 and 4) with a certain "safety" 
factor multiplying the error estimate.  It has been used extensively for 
non-linear problems and generally performs well.  
-- 
Regards,
Mike Hosea (mhosea@seas.smu.edu)
From: sean@pet.mni.mcgill.ca (Sean MARRETT)
Newsgroups: sci.math.num-analysis
Subject: Re: Robert Skeel, you suck.
Date: 10 Jan 93 02:48:55 GMT
Organization: Positron Imaging Labs, Montreal Neurological Institute

In article <C0M4w0.6p6@news.cso.uiuc.edu>, pms26964@uxa.cso.uiuc.edu (Phil Scopes) writes:
|> Robert Skeel is a well-known professor at the University of Illinois at
|> Urbana/Champaign, but he has one major problem--...
(More ad-hominem comments deleted)
 etc. The moral of the story is Never leave yourself
logged in at an open terminal. A nasty-minded prankster might use it
to make embarrassing postings to Usenet, for which you may be held
accountable. Or maybe a disgruntled student is *very* disappointed
with their grade. Who cares?

On with the regularly scheduled sci.math.num-analysis

--------------------------------------------------------
Sean Marrett                     email: sean@pet.mni.mcgill.ca 
wb213, PET Unit, Montreal Neurological Institute.
3801 University St., Montreal, Quebec.	H3A 2B4 
                                 tel:(514)-398-1537,1996 Fax: 8948 
Xref: sparky sci.math.num-analysis:3735 sci.math.stat:2711
From: kwakkel@cwi.nl (Fred Kwakkel)
Newsgroups: sci.math.num-analysis,sci.math.stat
Subject: WANTED: PD Statistical package
Date: 6 Jan 93 16:16:01 GMT
Followup-To: sci.math.num-analysis
Organization: CWI, Amsterdam

Hi,

We are looking for a PD statiscal package that produces equation(s)
from a set of data points and (a) previous equation(s). Preferable in C.

Please reply by e-mail because I do not regulary read this newsgroup.

Thanks !!

-- Fred

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
kwakkel@cwi.nl - centre for mathematics and computer science, amsterdam
Newsgroups: sci.math.num-analysis
From: brech@vision.ethz.ch (Christian Brechbuehler)
Subject: Re: Real to fraction...
Organization: Institute for Communication Technology, ETH Zuerich
Date: Fri, 8 Jan 1993 11:45:07 GMT

In article <1992Dec28.193616.13854@cc.umontreal.ca>, 
soubyran@ERE.UMontreal.CA (Soubyran Richard) writes:

|> Can anyone give me an algorithm to find the fractional
|> representation of a real number?

Essentially you construct a truncated continued fraction that
approximates the number.  Example: You want to find a fraction
representing approximately 3.1415926 (just a "random" number :-)).

3.14159  = 3 + 1/7.06251
	 = 3 + 1/(7 + 1/15.9966)     (* you decide to stop here *)
	~= 3 + 1/(7 + 1/16)
	 = 355/113

The latter fraction has an approximate value of 3.141592920.  An
alternative is not to truncate but to round, which keeps the ab-
solute values of the denominators above 2 and converges faster.
You can have both signs then.  Compare approximations for the
square root of three:

1.73205  = 1 + 1/1.36602 = 1 + 1/(1 + 1/2.73205) = ...(periodic)
	~= 1+1/(1+1/(2+1/(1+1/(2+1/(1+1/(2+1/3))))))   
	 = 239/138  ~=  1.73188

versus

1.73205  = 2 - 1/3.73205 = 2 - 1/(4 - 1/3.73205) = ...(periodic)
	~= 2-1/(4-1/(4-1/(4-1/4)))
	 = 362/209  ~=  1.73206

It shouldn't be too hard to turn this algorithm into a program.
A stopping criterion must be conceived.  Note that for numbers
with a precision of 16 digits (about "double" precision), the
generated sequence will diverge after 12 to 20 iterations. The
truncated fraction, of course, converges to the starting number.

=================================================================
	Christian Brechbuehler         <brech@vision.ethz.ch>

	Communication Technology Lab, Image Science Group
	Federal Institute of Technology (ETH) Zurich, Switzerland
=================================================================
From: ratier@velvet.laas.fr (Nicolas Ratier)
Newsgroups: sci.math.num-analysis
Subject: Karman'equations
Date: 8 Jan 93 00:26:23 GMT
Organization: LAAS-Centre National de la Recherche Scientifique Toulouse, France
Originator: ratier@velvet

Hi,

         I have to solve the Karman's system of equation :
-------------------------------------------------------------------
  (Wxxxx + 2 Wxxyy + Wyyyy) - (Fyy Wxx + Fxx Wyy - 2 Fxy Wxy) = P
  (Fxxxx + 2 Fxxyy + Fyyyy) + (Wxx Wyy - Wxy Wxy)       = 0
------------------------------------------------------------------- 

    on a rectangulare domaine, the plate is clamped.

so the boundary conditions for W (the deflection) are dW/dn = 0
                                                       W    = 0

but what are the boundary conditions for the fonction F ???????

I didn't find anything on it and it make me crasy ...
Does anybody had work on this problem ? 
Do you known a paper on it?

        please email me at :   ratier@laas.laas.fr
        Thanks

                           Nicolas 


-- 

   -------------------------------------
   |       L.A.A.S.   (France)         |
   |                                   |