SysIII/usr/src/man/man1/eqn.1

'\" e
.EQ
delim $$
.EN
.if t .ds ^ \s+4\v@.3m@^\v@-.3m@\s-4
.if n .ds ^ ^
.if t .ds ~ \s+4\v@.3m@~\v@-.3m@\s-4
.if n .ds ~ ~
.TH EQN 1
.SH NAME
eqn, neqn, checkeq \- format mathematical text for nroff or troff
.SH SYNOPSIS
.B eqn
[
.BR \-d xy
] [
.BR \-p n
] [
.BR \-s n
] [
.BR \-f n
]
[ files ]
.PP
.B neqn
[
.BR \-d xy
] [
.BR \-p n
] [
.BR \-s n
] [
.BR \-f n
]
[ files ]
.PP
.B checkeq
[ files ]
.SH DESCRIPTION
.I Eqn\^
is a
.IR troff (1)
preprocessor
for typesetting mathematical text
on a Wang Laboratories, Inc. C/A/T phototypesetter,
while
.I neqn\^
is used for the same purpose with
.IR nroff (1)
on typewriter-like terminals.
Usage is almost always:
.PP
.RS
eqn \|files \|\(bv \|troff
.br
neqn \|files \|\(bv \|nroff
.PP
.RE
or equivalent.
.PP
If no files are specified,
these programs
read from the standard input.
A line beginning with
.SM
.B \&.EQ
marks the start of an equation;
the end of an equation
is marked by a line beginning with
.SM
.BR \&.EN\*S .
Neither of these lines is altered,
so they may be defined in macro packages
to get
centering, numbering, etc.
It is also possible to designate two characters as
.IR delimiters ;
subsequent text between delimiters is then treated as
.I eqn\^
input.
Delimiters may be set to characters
.I x\^
and
.I y\^
with the command-line argument
.BI \-d xy\^
or (more commonly) with
.B delim
.I xy\^
between
.SM
.B \&.EQ
and
.SM
.BR \&.EN\*S .
The left and right delimiters may be the same character;
the dollar sign
is often used as such a delimiter.
Delimiters are turned off by
.BR "delim off" .
All text that is neither between delimiters nor between
.SM
.B \&.EQ
and
.SM
.B \&.EN
is passed through untouched.
.PP
The program
.I checkeq\^
reports missing or unbalanced delimiters and
\&\f3\s-1.EQ\s+1\fP/\f3\s-1.EN\s+1\fP pairs.
.PP
Tokens within
.I eqn\^
are separated by
spaces, tabs, new-lines, braces, double quotes,
tildes, and circumflexes.
Braces {\|} are used for grouping;
generally speaking,
anywhere a single character such as
.I x\^
could appear, a complicated construction
enclosed in braces may be used instead.
Tilde
(\*~)
represents a full space in the output,
circumflex
(\*^)
half as much.
.br
.if t .vs +1p
.PP
Subscripts and superscripts are produced with the keywords
.B sub
and
.BR sup .
Thus
.I "x\ \^sub\ \^j\^"
makes
$x sub j$,
.I "a\ \^sub\ \^k\ \^sup\ \^2\^"
\%produces
$a sub k sup 2$,
while
$e sup {x sup 2 + y sup 2}$
is made with
.IR "e\ sup\ \^{x\ \^sup\ \^2\ \^+\ \^y\ \^sup\ \^2\^}" .
Fractions are made with
.BR over :
.I "a\ \^over\ \^b\^"
yields $a over b$;
.B sqrt
makes square roots:
.I "1\ \^over\ \^sqrt\ \^{ax\ \^sup\ \^2+bx+c\^}\^"
results in
$1 over sqrt {ax sup 2 +bx+c}$ .
.PP
The keywords
.B from
and
.B to
introduce lower and upper
limits:
$lim from {n -> inf} sum from 0 to n x sub i$
is made with
.IR "lim\ from\ \^{n\ \^\->\ \^inf\ \^}\ \^sum\ \^from\ \^0\ \^to\ \^n\ \^x\ \^sub\ \^i" .
Left and right brackets, braces, etc., of the right height are made with
.B left
and
.BR right :
.I "left\ \^[\ \^x\ \^sup\ \^2\ \^+\ \^y\ \^sup\ \^2\ \^over\ \^alpha\ \^right\ \^]\ \^\*~=\*~\ \^1\^"
\%produces
.if t .vs +2p
$left [ x sup 2 + y sup 2 over alpha right ] ~=~ 1$.
Legal characters after
.B left
and
.B right
are braces, brackets, bars,
.if t .vs -2p
.B c
and
.B f
for ceiling and floor,
and \f3"\^"\fP for nothing at all (useful for a right-side-only bracket).
A
.B left
.I thing\^
need not have a matching
.B right
.IR thing .
.PP
.ne 4v
Vertical piles of things are made with
.BR pile ,
.BR lpile ,
.BR cpile ,
and
.BR rpile :
.I "pile\ \^{a\ \^above\ \^b\ \^above\ \^c\^}\^"
\%produces
$pile {a above b above c}$.
Piles may have arbitrary numbers of elements;
.B lpile
left-justifies,
.B pile
and
.B cpile
center (but with different vertical spacing),
and
.B rpile
right justifies.
Matrices are made with
.BR matrix :
.I "matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }\^"
\%produces
$matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }$.
In\ addition, there is
.B rcol
for a right-justified column.
.br
.if t .vs -1p
.PP
Diacritical marks are made with
.BR dot ,
.BR dotdot ,
.BR hat ,
.BR tilde ,
.BR bar ,
.BR vec ,
.BR dyad ,
and
.BR under :
.I "x\ \^dot\ \^=\ \^f(t)\ \^bar\^"
is
$x dot = f(t) bar$,
.I "y\ \^dotdot\ \^bar\ \^\*~=\*~\ \^n\ \^under\^"
is
$y dotdot bar ~=~ n under$,
and
.I "x\ \^vec\ \^\*~=\*~\ \^y\ \^dyad\^"
is
$x vec ~=~ y dyad$.
.PP
Point sizes and fonts can be changed with
.B size
.I n\^
or
.B size
\f3\(+-\fP\f2n\^\fP,
.BR roman ,
.BR italic ,
.BR bold ,
and
.BR font
.IR n .
Point sizes and fonts can be changed globally in a document by
.B gsize
.I n\^
and
.B gfont
.IR n ,
or by the command-line arguments
.BI \-s n\^
and
.BI \-f n\fR.\fP
.PP
Normally, subscripts and superscripts are reduced by
3 points from the previous size;
this may be changed by the command-line argument
.BI \-p n\fR.\fP
.PP
Successive display arguments can be lined up.
Place
.B mark
before the desired lineup point in the first equation;
place
.B lineup
at the place that is to line up vertically in subsequent equations.
.PP
Shorthands may be defined
or existing keywords redefined with
.BR define :
.PP
.RS
define \|thing \|% \|replacement \|%
.PP
.RE
defines a new token called
.I thing\^
that will be replaced by
.I replacement\^
whenever it appears thereafter.
The
.I %\^
may be any character that does not occur in
.IR replacement .
.PP
Keywords such as
.B sum
.EQ
( sum ),
.EN
.B int
.EQ
( int ),
.EN
.B inf
.EQ
( inf ),
.EN
and shorthands such as
>=
.EQ
(>=),
.EN
!=
.EQ
( != ),
.EN
and
\->
.EQ
(->)
.EN
are recognized.
Greek letters are spelled out in the desired case, as in
.B alpha
.EQ
( alpha ),
.EN
or
.SM
.B GAMMA
.EQ
( GAMMA ).
.EN
Mathematical words such as
.BR sin ,
.BR cos ,
and
.B log
are made Roman automatically.
.IR Troff (1)
four-character escapes such as
\f3\e(dd\fP (\(dd)
.if t and \f3\e(bs\fP (\(bs)
may be used anywhere.
Strings enclosed in double quotes (\f3"\^\fP.\|.\|.\^\f3"\fP)
are passed through untouched;
this permits keywords to be entered as text,
and can be used to communicate
with
.IR troff (1)
when all else fails.
Full details are given in the manual cited below.
.SH SEE ALSO
.I "Typesetting Mathematics\-User's Guide\^"
by B. W. Kernighan and L. L. Cherry.
.br
.I "New Graphic Symbols for \s-1EQN\s+1 and \s-1NEQN\s+1\^"
by C. Scrocca.
.br
mm(1), mmt(1), tbl(1), troff (1), eqnchar(7), mm(7), mv(7).
.SH BUGS
To embolden digits, parentheses, etc.,
it is necessary to quote them,
as in
\f3bold "12.3"\fP.
.br
See also
.SM
.I BUGS\^
under
.IR troff (1).