HDTenEightyP/NetNews huggingface dataset:
From: bronstei@inf.ethz.ch ()
Subject: Re: ode solver, different results from different packages
Originator: bronstei@ru3.inf.ethz.ch
Organization: Dept. Informatik, Swiss Federal Institute of Technology (ETH)
Date: Thu, 3 Sep 1992 15:51:28 GMT


In reply to:
>>	Article: 4600 of sci.math.symbolic
>>	From: qhuang@wiliki.eng.hawaii.edu (Qiming Huang)
>>	Date: Thu, 3 Sep 1992 10:20:37 GMT

the d.e. in question:
>>	x*dy/dx +a*x*y^2+2*y+b*x=0

>>	the solution given by macsyma is
>>                                                 
>>                                                (2 a sqrt(b) x)/sqrt(-a)
>>      y=((2 %c a b x - 2 %c sqrt(-a) sqrt(b)) %e
>>
>>                                                      (2 a sqrt(b) x)/sqrt(-a)
+ sqrt(-a) a sqrt(b) x -a)/(2 %c sqrt(-a) a sqrt(b) x %e
>> 
>> 2
+ a x)
>>	where %c is the integration constant.

This solution is correct with some assumptions on a and b (it wouln't be in
the macsyma manual otherwise).

>>	the solution given by mathematica is
>>	In:=DSolve[x*y'[x]+a*x*y^2+2*y+b*x==0, y[x],x]
>>	Out={{y[x]--> -(bx) -axy^2 +C[1] - 2y log[x]}}
>>	What went wrong?

Don't blame mathematica too quickly on that one: I think your input line
was wrong. Try the correct input:

Dsolve[x y'[x] + a x y[x]^2 + 2 y[x] + b x == 0, y[x], x]

and please do post it if you get a correct answer!
I thing the most likely answer to "What went wrong?" with the correct input,
is that this type of d.e. is not supported by mathematica.


For your information, AXIOM returns the following solution, which is correct
with somewhat weaker assumptions on a and b than macsyma's:

                                         +-----+
                +-----+               2x\|- a b        +-----+
         (- 2%c\|- a b  - 2%c a b x)%e           + a x\|- a b  + a
         ---------------------------------------------------------
                                         +-----+
                             +-----+  2x\|- a b     2
                     2%c a x\|- a b %e           - a x


where %c is the integration constant (AXIOM actually returns a first
integral, which you equate to any constant you want, e.g. %c, and then
solve for y(x)).

-----------------------------------------------------------------------------
    ____________
   /      /    /   /                Manuel Bronstein
  /---   /    /___/                 bronstein@inf.ethz.ch
 /      /    /   /                  Informatik, ETH Zuerich, Switzerland
 ----  /    /   /                   Tel: [41] (1) 254-7474
                                    Fax: [41] (1) 262-3973
-----------------------------------------------------------------------------
Newsgroups: sci.math.symbolic
From: singh@leland.Stanford.EDU (Harinder Singh)
Subject: Q.) MMA for Windows 3.1 - any happy users??
Organization: DSG, Stanford University, CA 94305, USA
Date: Mon, 31 Aug 92 17:47:27 GMT

Hi,

	I'd appreciate comments from any folks who have used Mma for
Windows (Mma version 2.1). Are you satisfied with it? How many meg
dram did it take to run happily under Windows 3.1? If you've also used
Mma on a Mac, please could you offer a few comments in comparison?

	Also, any experience with the limitations of the student
version (ie did anyone notice a significant performance problem
without the co-processor?)

	Many thanks,

			Inder


Newsgroups: sci.math.symbolic
From: dan@math.uiuc.edu (Daniel R. Grayson)
Subject: Re: mathematica solve and rules
Reply-To: dan@math.uiuc.edu
Organization: University of Illinois at Urbana
Date: Thu, 3 Sep 1992 11:37:28 GMT

try this:

Mathematica (ULTRIX) 1.2 (August 8, 1989) [With pre-loaded data]
by S. Wolfram, D. Grayson, R. Maeder, H. Cejtin,
   S. Omohundro, D. Ballman and J. Keiper
with I. Rivin and D. Withoff
Copyright 1988,1989 Wolfram Research Inc.

In[3]:= Solve[ a x^2 == c, x ]

               Sqrt[c]           Sqrt[c]
Out[3]= {{x -> -------}, {x -> -(-------)}}
               Sqrt[a]           Sqrt[a]

In[4]:= Reduce[ a x^2 == c , x , Mode->Generic]

             Sqrt[c]           Sqrt[c]
Out[4]= x == ------- || x == -(-------)
             Sqrt[a]           Sqrt[a]
Newsgroups: sci.math.symbolic
From: Matthias Imhof <gondwana@basalt.mit.edu> 
Subject: mathematica solve and rules
Organization: Massachvsetts Institvte of Technology
Date: Thu, 3 Sep 1992 00:46:55 GMT

when i use solve in mma, i get 

        u4      y4         y4
{{a -> ----- - -----, b -> --, 
       120 h   120 h       24
 
        u2    h u4   y2    h y4       y2
   c -> --- - ---- - --- - ----, d -> --, 
        6 h    36    6 h    18        2
 
                       3                   3
        u0   h u2   7 h  u4   y0   h y2   h  y4
   e -> -- - ---- + ------- - -- - ---- + -----, f -> y0}
        h     6       360     h     3      45
 
   }

but what i actally want is something like

        u4      y4         y4
a =    ----- - -----, b =  --, 
       120 h   120 h       24
 
        u2    h u4   y2    h y4       y2
   c =  --- - ---- - --- - ----, d =  --, 
        6 h    36    6 h    18        2
 
                       3                   3
        u0   h u2   7 h  u4   y0   h y2   h  y4
   e =  -- - ---- + ------- - -- - ---- + -----, f =  y0}
        h     6       360     h     3      45
 

which defines the solution to be a, b, c, d, e and f and not just the
transform rules which could be applied

is there a way to do that? can someone explain the concept of rules and  
definitions?

matthias
Newsgroups: sci.math.symbolic
Subject: Re: ode solver, different results from different packages
From: a_rubin@dsg4.dse.beckman.com (Arthur Rubin)
Date: 3 Sep 92 16:19:54 GMT

In <1992Sep3.102037.20539@news.Hawaii.Edu> qhuang@wiliki.eng.hawaii.edu (Qiming Huang) writes:

>Hi, I am trying to learn these different symbolic math packages
>such as mathmatica, mapleV, and macsyma. I tested one example
>listed on the macsyma manual for ordinary differential equations
>which writes as

>	x*dy/dx +a*x*y^2+2*y+b*x=0

>the solution given by macsyma is
>						  
>						  (2 a sqrt(b) x)/sqrt(-a)
>	y=((2 %c a b x - 2 %c sqrt(-a) sqrt(b)) %e

>	                  			        (2 a sqrt(b) x)/sqrt(-a)
>+ sqrt(-a) a sqrt(b) x -a)/(2 %c sqrt(-a) a sqrt(b) x %e
>   
>   2
>+ a x)
>where %c is the integration constant.

>the solution given by mathematica is
>In:=DSolve[x*y'[x]+a*x*y^2+2*y+b*x==0, y[x],x]
>Out={{y[x]--> -(bx) -axy^2 +C[1] - 2y log[x]}}

In:=DSolve[x*y'[x]+a*x*y[x]^2+2*y[x]+b*x==0, y[x],x]

is correct but Mathematica 2.0.2 can't solve it.
--
Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal)
My opinions are my own, and do not represent those of my employer.
My interaction with our news system is unstable; if you want to be sure I see a post, mail it.
Newsgroups: sci.math.symbolic
From: bhattas@athena.mit.edu (Saurav D Bhatta)
Subject: Maple question
Keywords: output file, C.
Organization: Massachusetts Institute of Technology
Date: Thu, 27 Aug 1992 16:09:13 GMT

i am writing a procedure that generates symbolic expressions which i want to use
in a C program. i want to output the expressions to a file. so my question is
basically this: how would i output stuff to a file in a format readable by a C
program.

i tried the following methods:

1) > C(expression,filename = `test.out`);
the problem with this was that every time i used this command, the file was
overwritten. since my procedure is going to generate a lot of different
expressions which i want to output to the file, i definitely do not want the file
to be overwirtten every time i write out a new expression (want an append mode);

2) > open(`test.out`);
   > write(C(expression));
   > close();
unfortulately here i never got past the write(C(expression)) statement, since the
computer hung up on me after that.

3) > writeto(`test.out`);
   > C(expression);
here the C expression was written to the terminal instead of the file.

thanks.

saurav
(bhattas@presto.mit.edu)

Newsgroups: sci.math.symbolic
From: forest@cs.unca.edu (Forest Davenport)
Subject: Re: random functions
Organization: University of North Carolina at Asheville
Date: Mon, 31 Aug 1992 21:31:29 GMT

Mathematica 2.0 for DEC RISC
Copyright 1988-91 Wolfram Research, Inc.
 -- X11 windows graphics initialized --

In[1]:= <<Statistics`ContinuousDistributions`

In[2]:= ndist = NormalDistribution[mu,sigma]

Out[2]= NormalDistribution[mu, sigma]

In[3]:= mu = 5.;

In[4]:= sigma = 1.;

In[5]:= rannor = Table[Random[ndist],{5}]

Out[5]= {4.62584, 6.841, 4.7538, 3.76216, 4.59975}


	Five random numbers distributed normally with
	a mean of 5.0 and a sigma of 1.0 .

Newsgroups: sci.math.symbolic,sci.math
From: us291442@mmm.serc.3m.com (Mark B. Mizen)
Subject: Mathematica execution time
Organization: 3M Company
Date: Mon, 31 Aug 92 20:27:27 GMT

I have Mathematica 2.0 for MS Windows and need to complete
a series of Mathematica calculations that take an extremely long
time to run.  I need to know if I can in any way increase the speed of
calculation by decreasing the precision of the calculation.
Hopefully, this change would also decrease memory requirements.

I have called Wolfram technical support and they were unable to
definitively answer my questions.  Various attempts on my part
seem to fail.  Does anyone have any suggestions?  Thanks for
any help.

Mark Mizen
mbmizen@mmm.com
(612) 733-3925
From: 00s0davis@bsu-ucs.uucp
Newsgroups: sci.math.symbolic
Subject: symbmath.hlp
Date: 2 Sep 92 02:14:56 GMT

Dear netters,
     I'm having some problems getting Symbmath 2.1 to interface
with plotdata 1.1. I've tried using my own functions, defining
them in the way set out in the Symbmath manual ( changing the
output to Disk, running table(x^2, x from -10 to 10 step 1), then
changing the output back to Window) and as described in the
plotdata help files. If any one knows what the problem is, please
e-mail me at 00s0davis@leo.bsuvc.bsu.edu.
                                   Thank you,
                                             Spencer Davis

*****************************************************************
Give me convenince or give me death!
                                   Dead Kennedys
*****************************************************************
Newsgroups: sci.math.symbolic
From: markm@wri.com
Subject: Re: Saving Mma sounds in .snd format
Reply-To: markm@wri.com
Organization: Wolfram Research, Inc.
Date: Thu, 27 Aug 1992 17:45:00 GMT

In article <739@capmkt.COM> charles@capmkt.COM (Charles Neveu) writes:
> Is it possible to save Mathematica-generated sounds to .snd files,
> esp. on the NeXT? The standard method of Displaying to a stream saves
> the file in Mathematica format.

Yes, this is possible.  To save Mathematica sounds as "*.snd" files, there are  
the following steps:

1. Create the sound in Mathematica
2. Start the "/NeXTDeveloper/Demos/SoundPlayer" program, or any of the 
	available sound editors (SoundWorks, EdSound, etc.).
3. Open a "new" document in the sound program.
4. In Mathematica, select the cell in which the sound resides (the
	PostScript cell).
5. Copy the cell into the NeXT Pasteboard (by pressing Command-C, or
	selecting the "Copy" menu option).
6. Paste the cell into the sound program.
7. Save the sound from the sound program, using Command-s, or
	Command-S.

Now the sound will be saved as a native "*.snd" file with a NeXT sound header  
attached to it.

Note:  You can find this Technical Note along with many others on MathSource.   
MathSource can be accessed by sending the message "help intro" to  
mathsource@wri.com.  Or, if you prefer to search the database for other  
technical notes, use the command "find technical note".

--Mark Moline
Wolfram Research, Inc.
markm@wri.com


Newsgroups: sci.math.symbolic
From: branham@binah.cc.brandeis.edu (Tom Branham, Biophysics Grad. Brandeis)
Subject: Re: Mathematica execution time
Reply-To: branham@binah.cc.brandeis.edu
Organization: Brandeis University
Date: Tue, 1 Sep 1992 03:32:15 GMT

How much memory do you have in your system now?  Even a moderate change
in the memory size Can (Notice I did not say Will, dependent on the application
size, other programs running, etc.....) Drastically improve the performance
of a windows application. Memory prices have dropped a bit of late too, 
although as a grad student I am still well aware that it is not pocket
change :)
                               ........Tom Branham
Newsgroups: sci.math.symbolic,sci.math
From: strassen@iam.unibe.ch (Tyko Strassen)
Subject: MAPLE-package for plane algebraic curves available
Keywords: geometry, algebra, projective
Reply-To: schwendi@iam.unibe.ch
Organization: Dept. of Computer Science, University of Berne, Switzerland
Date: Thu, 3 Sep 1992 19:43:39 GMT


One of our students, Stefan Schwendimann, has written as his diploma work
a MAPLE-package for algebraic curves in the affine and projective plane.

The package contains functions for: various transformations, multiple
components, normal forms, analysis of singularities, multiplicities,
tangents, polar, linear systems, intersections (-multiplicities), Hessian,
inflections, explicit and implicit representations, curve plots.

Modern software engeneering and software development was a major part of the 
whole project, including that the package is stable and well documented
(e.g. MAPLE help files are available). Part of the package will be a
future member of the MAPLE share library.



Everything (source code and documentation) is available via ftp:

        ftp-site: siam.unibe.ch     (130.92.66.11)
        file: pub/AlgCurve.tar.Z



Greetings from Switzerland,

                         Tyko Strassen


PS: Questions please to  <schwendi@iam.unibe.ch>


----------------------------------------------------------------------------

Example how to get and install the whole package (output is omitted):

$ ftp siam.unibe.ch
Name (.....): ftp
Password: (type here in your complete email-address)
ftp> bin
ftp> cd pub
ftp> get AlgCurve.tar.Z
ftp> bye
$ uncompress AlgCurve.tar.Z
$ tar -fx AlgCurve.tar
$ cd AlgCurve
$ more README
From: t68@nikhefh.nikhef.nl (Jos Vermaseren)
Newsgroups: sci.math.symbolic
Subject: Re: long symbolic runs
Date: 1 Sep 92 07:46:33 GMT
Reply-To: t68@nikhefh.nikhef.nl (Jos Vermaseren)
Organization: Nikhef-H, Amsterdam (the Netherlands).

I have run rather long programs with FORM (it was designed for that).
For instance: we have run here some integrals in QCD that took together
154 hours on an Apollo DN10000. The final answers fit on four lines.
In the middle there was an integral that took about 200 Mbytes of diskspace.
The program is very much optimized so with the exception of (very maybe)
schoonschip no other program can handle this (to preempt requests for people
who would like to try this with their favorite system). The strategy was
to parcel the program a little bit in handier chunks and let UNIX make
run the show.
In another big run that took 305 hours on a NeXT station (with a thunder
storm above my appartment after about 10 days. that makes me nervous) I
have been trying something with designing Groebner bases. 
And YES, my conclusion with things like this is that there should be
a mechanism to save intermediate results so that the program may be
restarted. (As far as this is possible. Some problems won't allow this.
Backing up 200 Mbytes is not always possible cq desirable).
Most designers however never run monsterjobs like this, so they never think
of this.

Jos Vermaseren
Newsgroups: sci.math.symbolic
From: fmmoore@athena.mit.edu (Fes-Mike Moore)
Subject: function arguments type checking in MapleV
Organization: Massachusetts Institute of Technology
Date: Tue, 25 Aug 1992 23:36:43 GMT

I'm trying to define type/procargs as described in ?type[argcheck] (page
223 of the Maple V Library Reference manual).  This is what I'm
entering:

	> `type/expectationargs` := [indexed * function(indexed)];
              type/expectationargs := [indexed function(indexed)]
	> expectation := proc(expr)
	> local i,j,k,l;
	>   if not type([expr], expectationargs) then
	>       ERROR(
	>   `invalid arguments; must be in form of indexed * function(indexed)`)
	> fi;
	> i := op(1,op(1,expr)); 
	> j := op(2,op(1,expr)); 
	> k := op(1,op(1,op(2,expr))); 
	> l := op(2,op(1,op(2,expr))); 
	> print(i,j,k,l) 
	> end;

When I run the program, though, I get:

	> testarg := z[a,b]*conjugate(z[fes,mike]);
                   testarg := z[a, b] conjugate(z[fes, mike])

	_____________________________________________________________________
	> expectation(testarg);
	Error, (in expectation) testing against an invalid type

Aren't function and indexed valid types?  If so, why can't they be used
in this manner?  Or am I overlooking something else?  In general I can
do:

	> type(conjugate(x), function(name));
                                      true

so I presumably shouldn't have any problems with this...

Thanks for your help...
--
Fes-Mike Moore
CSSC Student Consultant
From: ricampb@afterlife.ncsc.mil (Robert Campbell)
Newsgroups: sci.math.symbolic,uiuc.mathematica
Subject: Re: Mma Pathnames under Windows
Date: 26 Aug 92 10:37:08 GMT
Organization: The Great Beyond

In article <1992Aug24.070159.13875@ucc.su.OZ.AU> colinr@extro.ucc.su.OZ.AU (Colin Rose) writes:
>Under Windows, file names are limited to 8 characters. As a 
>result, when a package contains an instruction to load another
>package whose file name exceeds 8 characters, Mma does not find
>it --- at least on our setup -- and returns a can't open meassage.
>Thus far, I have solved this problem by doctoring the
>names of loaded packages to match their file names under Windows.
>For instance, if I change the above instruction to:
>
>   BeginPackage["Statisti`NormalDi`",
>             "Statisti`Descript`",
>             "Statisti`Common`Distribu`",
>             "Statisti`InverseS`"]
>
>          I have no problem loading the normal distribution package 
>under Windows.

The problem that you cite is real. It is caused by the fact that the
translation done by the ContextToFilename function is, at best, a
crude one - truncating names to 8 characters on DOS based systems.
Version 2.1 corrected this for the packages in the standard distribution
by letting this function recognize each of the standard packages and
make the proper translation to a path. For any package that you install
beyond that, though, you will have to instruct ContextToFilename how
to translate the path. Thus, if you install the package with context
Algebra`PermutationGroups` as the file PACKAGES\ALGEBRA\PERMGPS.M you
will have to execute the rule:
	ContextToFilename["Algebra`PermutationGroups`"] =  \
		"PACKAGES\ALGEBRA\PERMGPS.M"
Note that the translation done by ContextToFilename is only used by
the Needs and BeginPackage commands, not the Get (ie <<filename)
command.

					- Robert Campbell -
Newsgroups: sci.math.symbolic,uiuc.mathematica
From: jpg41900@uxa.cso.uiuc.edu (Justin Gallivan)
Subject: Re: MMA Version?
Organization: University of Illinois at Urbana
Date: Thu, 27 Aug 1992 19:34:55 GMT

butscher@helios.physics.utoronto.ca (Adrian Butscher) writes:

>In article <1992Aug26.103708.26823@afterlife.ncsc.mil> ricampb@afterlife.ncsc.mil (Robert Campbell) writes:

>>...Version 2.1 corrected this for the packages in the standard distribution...

>What is the latest version of MMA for the Macintosh?  The latest I've seen is 
>version 2.03.

>Adrian

We are currently using Mathematica 2.102 Enhanced in our lab of Macintoshes.
Versions of 2.1 for the other platforms are for the most part available now
or are soon to be so.

-- 
Justin Gallivan                Calculus&Mathematica Development Team
gallivan@after.math.uiuc.edu   University of Illinois at Urbana-Champaign
-------------------------------------------------------------------------
"That's CAUCASIAN trash to you, pal" -C.M. Dockstader 8 May, 1992
From: fhl@milton.u.washington.edu (Dean Pentcheff)
Newsgroups: sci.math.symbolic
Subject: Buying Mathematica for Sparcs, not from Wolfram Research
Summary: Are there other (cheaper) vendors?
Date: 26 Aug 92 22:32:09 GMT
Reply-To: dean2@tbone.biol.scarolina.edu (Dean Pentcheff)
Followup-To: sci.math.symbolic
Distribution: usa
Organization: Department of Biology, University of South Carolina, Columbia

Can one buy Mathematica for the Sparcstation from anyone other than
Wolfram Research?  In the PC software world, buying software from
anyone other than the original company is always cheaper.  Is this
true for Mathematica?  Does anyone other than Wolfram sell the
Sparcstation version?

Thanks.

-Dean
From: saxena@cs.albany.edu (Tushar Saxena)
Newsgroups: sci.math.symbolic
Subject: Macaulay Source Code Site
Keywords: Macaulay, computer algebra, site
Date: 4 Sep 92 15:40:55 GMT
Article-I.D.: cs.1992Sep4.154055.3420
Organization: The University at Albany, Comp. Sci. Dept.
Originator: saxena@watson.albany.edu

Can somebody please tell me where I can get a copy of Macaulay?
I need it badly.

Thanks

ttfn
	-Tush.

--------------------------------------------------------------------------------
And any fool knows a dog needs a home, A shelter from pigs on the wing.
        -Roger Waters
--------------------------------------------------------------------------------
email : saxena@cs.albany.edu                        Computer Science Department
Phone : 518-442-3388				    SUNY Albany
Tushar Saxena					    Albany NY 12222 (USA)
--------------------------------------------------------------------------------
Newsgroups: sci.math.symbolic
From: john@aquarius.unm.edu (John Prentice)
Subject: MPP implementations of symbolic algebra systems
Date: Thu, 03 Sep 92 02:36:08 GMT
Organization: Dept. of Physics & Astro, University of New Mexico, Albuquerque

Anyone know if people are working on implementations of symbolic algebra
systems on massively parallel supercomputers?  If so, what precisely is
being parallelized?  

A data point is that TMC has a Lisp compiler for the CM-2, anyone know
if they toyed with symbolic algebra on that system?

John
-- 
Dr. John K. Prentice                      
Partner, Quetzal Computational Associates    
3200 Carlisle N.E., Albuquerque, NM   87110-1664; 505-889-4543
john@aquarius.unm.edu -or- jkprent@cs.sandia.gov -or- prentice@rufous.cs.unm.edu
From: rosentha@bldrdoc.gov (Peter Rosenthal 303-497-5844)
Newsgroups: sci.math.symbolic
Subject: NDSolve question
Date: 3 Sep 92 16:48:16 GMT
Organization: National Institute of Standards and Technology

I would like to solve a set of coupled non-linear, non-stiff
second order ODE's.  One of the terms in the equation will be
a gaussian noise source.  The standard deviation of the 
noise term is fixed by the time increment used by the solver.

I would like to use NDSolve in mathematica, but I need to fix
the stepsize of the integrator.  There doesn't seem to be anyway
to do this, based on what I've read in the manual.

One method I tried was to generate a noise function before calling NDSolve
that consisted of an InterpolatingFunction generated from Gaussian random 
data.  Then NDSolve worked fine.  The problem with this approach is
that it requires a lot of extra memory to store a long random time series
necessary to span the entire time span.  I would much rather generate the
noise at each time step, and not have to store an entire sequence.

One approach would be to use a fixed step 4th order Runge Kutta
routine that spits out an InterpolatingFunction, but I don't know
if I have the time to write one.                     

Does anyone know how to set up a fixed time step version
of NDSolve?

Thanks in advance

Peter Rosenthal




if I have the time to code one.N Interpolating function

from data generated by a gaussian 
-- 
Peter Rosenthal       Email rosenthal@cmg.eeel.nist.gov