2004.03_Brave Gnu World-the Monthly Gnu Column.pdf

COMMUNITY

Brave GNU World

W elcome to another issue of the

This column looks into projects and current

Brave GNU World, where we

take a look at two projects to

avoid neglecting the technical side of

Community affairs.

affairs in the world of free software from the per-

spective of the GNU Project and the FSF. In this issue, we will be focusing on:

Jaxodraw

Thomas Theußl drew my attention to a

program called Jaxodraw by mailing me

at the usual address [1]. Jaxodraw [5] is

a program that allows users to create

Feynman diagrams interactively.

Richard Feynman was one of the most

influential physicists of the 20th century.

He and his fellow-researchers, Sin-Itiro

Tomonaga and Julian Schwinger, were

awarded the Nobel Prize in 1965 for their

work on quantum electrodynamics. His

“Feynman Lectures on Physics” are the

first (and best) read for many students.

Feynman diagrams are time/space dia-

grams that describe the interaction of

elements in space, where the x-axis rep-

resents space, and the y-axis time.

Jaxodraw provides a GUI using the

Axodraw package [6] by J.A.M. Ver-

maseren to do so. This allows users to

create diagrams with a mouse. Details

can be then added using the keyboard.

The diagrams use the XML format, and

can be output either as (encapsulated)

PostScript or Latex code.

Jaxodraw, Mom and coin slots in hotel rooms. BY GEORG C.F. GREVE

Latex formatted output was one of the

Jaxodraw authors’ (Daniele Binosi and

Lukas Theussl) major motivations, as

they were looking for a way to embed

diagrams in scientific publications with a

minimum of effort. The Latex publishing

System has been popular for many years

now on account of its flexibility and effi-

ciency. However, it was hard

to achieve the desired results

without a WYSIWYG dis-

play.

As the name suggests, Jax-

odraw was programmed in

Java. This makes the pro-

gram platform independent

to a large extent. But unfor-

tunately, it will only run

correctly on the Sun Java

implementation. Quite a few

issues arose with IBM’s Run-

time Environment. Refer to

[7] for more details. Jaxo-

draw itself was released

under the GPL. The develop-

ers have published the

Jaxodraw manual as a scien-

tific paper at [8], and ask users of the

program to refer to this page in their own

work. This allows the authors to more

closely monitor how many people are

actually use Jaxodraw.

There is an extremely interesting cor-

relation between this and the discussion

in issue #37 ([9]) of Brave GNU World on

free software and its influence on sci-

ence. It clearly demonstrates how free

software itself can form the basis of a sci-

entific publication.

Figure 2: The winner of

the Nobel Prize for

Physics, Richard Feyn-

man – a firm proponent

of describing complex

processes in a way that

non-experts could

understand.

thing to do with text layout, but is defi-

nitely not aimed at scientists. Most

GNU/Linux users are familiar with GNU

Troff (Groff, [10]), mostly from reading

its numerous manpages (you can type

man command to view formatted pages

describing the commands of Unix-type

Systems). Few are aware that Groff is a

fully-fledged text layout sys-

tem like Latex or Lout that

allows users to create Post-

Script documents.

Groff needs only a fraction

of the resources that Latex

requires. It will run without

fuss on a 386 with 8MB

RAM and a 250MB hard

disk. The careful use of

resources that GNU/Linux

and Groff display is what

made the Canadian author,

Peter Schaffter, opt for this

combination. Just like many

of his fellow-authors, Peter

is not well off. He uses com-

puters that people give to

him, and this may mean

that they are a whole generation behind

state-of-the-art machines – as he puts it

himself, they are “resource challenged”.

Groff may not be easy to use, as the

commands are typically quite terse and

not always intuitive. This is why Peter

Schaffter starting working on Mom [11].

In a similar fashion to the way Latex is

built on Tex, Mom is a set of macros for

Groff that provides a simple syntax. At

the same time, it allows highly granular

control over the generated documents,

which can easily hold sway with other

DTP solutions, without requiring in-

depth knowledge of Groff’s somewhat

cryptic syntax.

Figure 1: Jaxodraw is a scientific program that

allows users to create Feynman diagrams. It pro-

vides a graphical interface and can produce

various output formats.

Mom

The next project, which is a very much

an insider tip at present, also has some-

March 2004

www.linux-magazine.com

The Monthly GNU Column

Brave GNU World

COMMUNITY

Figure 3: GNU Troff (Groff) is the GNU version of

the well-known Unix tool troff.

tems only use Tex,

rather than Groff for

printed output. Groff

would provide an excel-

lent output format for

XML-based documents,

as O’Reilly has already

demonstrated with its

combination of Doc-

book SGML and Groff in

“Programming Perl”.

In Florian Cramer’s opinion, Peter

Schaffter is one of the unsung heroes of

free software. Florian was particularly

impressed at how well Peter Schaffter

received his suggestion (concerning

automatic creation of a table of con-

tents), and at the speed with which this

suggestion was implemented. If you

want to contact Peter Schaffter, make

sure that the subject line of your mes-

sage includes either the word “Groff” or

“Mom”, as his spam filter will ditch any

other email messages.

Even if the program will need a few

minor functions adding at some stage, it

is stable, and Schaffter intends to leave it

up to the users to decide exactly which

add-ons make sense. The decision to

release Mom as a free software tool

under the GPL was a conscious decision

taken by Peter Schaffter that not only

reflects his gratitude to the Community,

but also his commitment to underlying

social implications of free software.

bies, or at airports in Europe cannot pos-

sibly cost more than an initial

investment of about £350 (500 Euros,

$640) and monthly charges of about £21

(30 Euros, $38) for a broadband flat-rate.

The charge rate for this access is typi-

cally between £2 – £7 (3-10 Euros, $4-13)

for half an hour. It is quite common for

providers to require the use of prepaid

cards, which are usually sold out. If you

happen to find the right card, you might

think you would be up and running, but

unfortunately the providers seem inca-

pable of designing stable websites that

will work with arbitrary browsers.

When you consider how little it actu-

ally costs to install and run wireless

Internet hotspots, in comparison with

water and sanitary installations, for

example, users can expect to find coin

slots in hotel showers and bathrooms

any day now. We have been living in the

plumbing age for quite a while now, the

information age seems to be far distant

in the face of developments like this.

That’s all for this month. As usual, I

would like everyone to get in touch with

comments, questions, and ideas to the

usual address [1].

Mom is aimed at users who need a lay-

out program, but have not felt up to

tackling Groff’s syntax, authors who

need to layout their work quickly and

without any fuss, and newcomers who

value a well-documented solution. Peter

Schaffter has put a lot of effort into the

manual. He is convinced that good docu-

mentation is a major element of program

development. The manual was released

under the Free Documentation License

(FDL), and is available in HTML format.

Florian Cramer, who drew my atten-

tion to Mom, quotes three main reasons

for using Mom:

•a unique combination of structured

document processing with excellent

manual layout control facilities

• frugal resource requirements

• less complex than Latex, which facili-

tates individual modifications

One of the program’s limitations is the

fact that it is not suited to scientific pub-

lication – in contrast to Latex – as it

cannot handle cross-references, indices,

or numbered illustrations. The choice of

output formats is also limited. Mom is

designed to produce Post-

Script output. The

commands grotty and gro-

html also allow cleartext

and HTML output, but they

were not part of Peter’s

original game plan.

■

INFO

[1] Send ideas, comments, and questions to:

column@brave-gnu-world.org

[2] Homepage of GNU-Projects: http://www.

gnu.org/

[3] Georg’s Brave GNU World homepage:

http://brave-gnu-world.org

[4] “We run GNU¯Initiative”: http://www.

gnu.org/brave-gnu-world/rungnu/

rungnu.html

[5] Jaxodraw: http://altair.ific.uv.es/

~JaxoDraw/home.html

[6] Axodraw: http://www.nikhef.nl/~form/

FORMdistribution/axodraw/

[7] Known bugs in Jaxodraw: http://altair.ific.

uv.es/~JaxoDraw/bugs.html

[8] Jaxodraw study: http://arxiv.org/abs/

hep-ph/0309015

[9] Georg C.F. Greve,“Brave GNU World”,

Linux Magazine, issue 37, p.89

[10]GNU Troff: http://www.gnu.org/software/

groff/groff.html

[11] Mom Macro set: http://www.ncf.ca/

~df191/mom.html

[12] The GNU Manifesto: http://www.gnu.

org/gnu/manifesto.html

Coin Slots in Hotel Rooms?

Finally, let’s expose a new trend which is

on the increase: wireless Internet access,

but at absurdly high prices. Installing

wireless Internet hotspots in hotel lob-

Alternatives to Tex

Originally programmed by a

Canadian author for his

own use, Mom offers exactly

what many users need: a

simple, but feature-rich text

layout tool. Florian Cramer

goes one step further and

asks why XML/SGML sys-

Figure 4: Internet Wireless LAN hotspots, such as the one at

Munich airport, are on the increase. However, the asking price in

no way reflects the effort put in by service providers.

www.linux-magazine.com

March 2004

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