·  Home
+   man pages
 -> Linux -> FreeBSD -> OpenBSD -> NetBSD -> Tru64 Unix -> HP-UX 11i -> IRIX
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

man pages->FreeBSD man pages -> eqn (1)
 Title
 Content
 Arch
 Section All Sections 1 - General Commands 2 - System Calls 3 - Subroutines 4 - Special Files 5 - File Formats 6 - Games 7 - Macros and Conventions 8 - Maintenance Commands 9 - Kernel Interface n - New Commands

## EQN(1)

### Contents




### NAME[Toc][Back]

       eqn - format equations for troff


### SYNOPSIS[Toc][Back]

       eqn [ -rvCNR ] [ -dxy ] [ -Tname ] [ -Mdir ] [ -fF ] [ -sn ] [ -pn ]
[ -mn ] [ files... ]

It is possible to have whitespace between a command line option and its
parameter.


### DESCRIPTION[Toc][Back]

       This manual page describes the GNU version of eqn, which is part of the
groff document formatting system.  eqn compiles descriptions  of  equations
embedded	within troff input files into commands that are understood
by troff.	Normally, it should be invoked using the -e option  of
groff.	The  syntax  is quite compatible with Unix eqn.  The output of
GNU eqn cannot be processed with Unix troff; it must be processed  with
GNU  troff.   If  no  files are given on the command line, the standard
input will be read.  A filename of - will cause the standard  input  to

eqn  searches  for  the file eqnrc in the directories given with the -M
option first, then in /usr/share/tmac, /usr/share/tmac, and finally  in
the  standard  macro directory /usr/share/tmac.	If it exists, eqn will
process it before the other input files.  The -R option prevents  this.

GNU eqn does not provide the functionality of neqn: it does not support
low-resolution, typewriter-like devices	(although  it  may  work  adequately
for very simple input).


### OPTIONS[Toc][Back]

       -dxy   Specify  delimiters  x and y for the left and right end, respectively,
of in-line  equations.   Any  delim  statements  in  the
source file overrides this.

-C     Recognize  .EQ  and  .EN even when followed by a character other
than space or newline.

-N     Don't allow newlines within delimiters.  This option allows  eqn
to recover better from missing closing delimiters.

-v     Print the version number.

-r     Only one size reduction.

-mn    The  minimum  point-size	is n.  eqn will not reduce the size of
subscripts or superscripts to a smaller size than n.

-Tname The output is for device name.  The only effect of  this	is  to
define a macro name with a value of 1.  Typically eqnrc will use
this to provide definitions appropriate for the  output  device.
The default output device is ps.

-Mdir  Search dir for eqnrc before the default directories.

-fF    This is equivalent to a gfont F command.

-sn    This  is equivalent to a gsize n command.  This option is deprecated.
eqn will normally set equations at whatever the  current
point size is when the equation is encountered.

-pn    This  says  that	subscripts and superscripts should be n points
smaller than the surrounding text.  This option  is  deprecated.
Normally	eqn  makes  sets subscripts and superscripts at 70% of
the size of the surrounding text.


### USAGE[Toc][Back]

       Only the differences between GNU eqn and Unix eqn are described here.

Most of the new features of GNU eqn are based on TeX.  There  are  some
references  to the differences between TeX and GNU eqn below; these may
safely be ignored if you do not know TeX.

Automatic spacing    [Toc]    [Back]
eqn gives each component of an equation a type, and adjusts the spacing
between components using that type.  Possible types are:

ordinary     an ordinary character such as 1 or x;
_
operator     a large operator such as >;

binary	    a binary operator such as +;

relation     a relation such as =;

opening	    a opening bracket such as (;

closing	    a closing bracket such as );

punctuation  a punctuation character such as ,;

inner	    a subformula contained within brackets;

suppress     spacing that suppresses automatic spacing adjustment.

Components of an equation get a type in one of two ways.

type t e
This  yields  an equation component that contains e but that has
type t, where t is one of the types mentioned above.  For  example,
times is defined as

type "binary" \(mu

The name of the type doesn't have to be quoted, but quoting protects
from macro expansion.

chartype t text
Unquoted groups of characters are split up into individual characters,
and  the  type  of  each  character  is looked up; this
changes the type that is stored for each character; it says that
the characters in text from now on have type t.  For example,

chartype "punctuation" .,;:

would  make  the	characters .,;: have type punctuation whenever
they subsequently appeared in an equation.  The type t can  also
be  letter  or  digit;  in these cases chartype changes the font
type of the characters.  See the Fonts subsection.

New primitives    [Toc]    [Back]
e1 smallover e2
This is similar to over; smallover reduces the size  of  e1  and
e2;  it  also  puts less vertical space between e1 or e2 and the
fraction bar.  The over primitive corresponds to the  TeX  \over
primitive  in  display styles; smallover corresponds to \over in
non-display styles.

vcenter e
This vertically centers e about the math axis.  The math axis is
the vertical position about which characters such as + and - are
centered; also it is the vertical position used for the  bar  of
fractions.  For example, sum is defined as

{ type "operator" vcenter size +5 \(*S }

e1 accent e2
This  sets  e2 as an accent over e1.  e2 is assumed to be at the
correct height for a lowercase letter; e2  will  be  moved  down
according  if  e1  is taller or shorter than a lowercase letter.
For example, hat is defined as

accent { "^" }

dotdot, dot, tilde, vec and dyad	are  also  defined  using  the
accent primitive.

e1 uaccent e2
This  sets e2 as an accent under e1.  e2 is assumed to be at the
correct height for a character without a descender; e2  will  be
moved  down  if e1 has a descender.  utilde is pre-defined using
uaccent as a tilde accent below the baseline.

split "text"
This has the same effect as simply

text

but text is not subject to macro expansion because it is quoted;
text will be split up and the spacing between individual characters

nosplit text
This has the same effect as

"text"

but because text is not quoted  it  will	be  subject  to  macro
expansion;  text	will  not  be split up and the spacing between
individual characters will not be adjusted.

e opprime
This is a variant of prime that acts as an operator  on  e.   It
produces	a  different  result  from  prime  in  a  case such as
A opprime sub 1: with opprime the 1 will	be  tucked  under  the
prime  as a subscript to the A (as is conventional in mathematical
typesetting), whereas with prime the 1 will be  a  subscript
to  the  prime character.  The precedence of opprime is the same
as that of bar and under, which is higher than  that  of	everything
except  accent and uaccent.  In unquoted text a ' that is
not the first character will be treated like opprime.

special text e
This constructs a new object from e using a troff(1) macro named
text.   When the macro is called, the string 0s will contain the
output for e, and the number registers 0w, 0h,  0d,  0skern  and
0skew will contain the width, height, depth, subscript kern, and
skew of e.  (The subscript kern of an object  says  how  much  a
subscript  on  that  object  should be tucked in; the skew of an
object says how far to the right of the center of the object  an
accent over the object should be placed.)  The macro must modify
0s so that it will output the desired result with its origin  at
the  current point, and increase the current horizontal position
by the width of the object.  The number registers must  also  be
modified so that they correspond to the result.

For  example,  suppose  you wanted a construct that cancels' an
expression by drawing a diagonal line through it.

.EQ
define cancel 'special Ca'
.EN
.de Ca
.ds 0s \Z'\\*(0s'\v'\\n(0du'\D'l \\n(0wu -\\n(0hu-\\n(0du'\v'\\n(0hu'
..

Then you could cancel an expression e with cancel { e }

Here's a more complicated construct that draws a	box  round  an
expression:

.EQ
define box 'special Bx'
.EN
.de Bx
.ds 0s \Z'\h'1n'\\*(0s'\
\Z'\v'\\n(0du+1n'\D'l \\n(0wu+2n 0'\D'l 0 -\\n(0hu-\\n(0du-2n'\
\D'l -\\n(0wu-2n 0'\D'l 0 \\n(0hu+\\n(0du+2n''\h'\\n(0wu+2n'
.nr 0w +2n
.nr 0d +1n
.nr 0h +1n
..

Customization    [Toc]    [Back]
The  appearance of equations is controlled by a large number of parameters.
These can be set using the set command.

set p n
This sets parameter p to value n ; n is an integer.   For  example,

set x_height 45

says that eqn should assume an x height of 0.45 ems.

Possible parameters are as follows.  Values are in units of hundredths
of an em unless otherwise  stated.   These  descriptions
are intended to be expository rather than definitive.

minimum_size	      eqn  will  not set anything at a smaller
point-size than this.  The value	is  in
points.

fat_offset	      The  fat primitive emboldens an equation
by overprinting two copies of the  equation
horizontally offset by this amount.

over_hang 	      A fraction bar will be longer  by  twice
this  amount  than  the  maximum	of the
widths of the numerator and denominator;
in  other  words,  it  will overhang the
numerator and denominator  by  at  least
this amount.

accent_width	      When bar or under is applied to a single
character, the line will be  this  long.
Normally,  bar  or under produces a line
whose length is the width of the	object
to  which  it  applies; in the case of a
single character, this tends to  produce
a line that looks too long.

delimiter_factor	      Extensible  delimiters produced with the
left and right primitives  will  have  a
combined	height	and  depth of at least
this many thousandths of twice the maximum
amount  by  which  the sub-equation
that the delimiters enclose extends away
from the axis.

delimiter_shortfall     Extensible  delimiters produced with the
left and right primitives  will  have  a
combined	height and depth not less than
the  difference  of  twice  the  maximum
amount  by  which  the sub-equation that
the delimiters enclose extends away from
the axis and this amount.

null_delimiter_space    This  much  horizontal space is inserted
on each side of a fraction.

script_space	      The width of subscripts and superscripts
is increased by this amount.

thin_space	      This  amount  of	space is automatically
inserted after punctuation characters.

medium_space	      This amount of  space  is  automatically
inserted on either side of binary operators.

thick_space	      This amount of  space  is  automatically
inserted on either side of relations.

x_height		      The  height of lowercase letters without
ascenders such as x.

axis_height	      The height above	the  baseline  of  the
center  of  characters  such as + and -.
It is important that this value is  correct
for the font you are using.

default_rule_thickness  This  should set to the thickness of the
\(ru character, or the thickness of horizontal
lines  produced  with  the  \D
escape sequence.

num1		      The  over  command  will	shift  up  the
numerator by at least this amount.

num2		      The  smallover command will shift up the
numerator by at least this amount.

denom1		      The over command	will  shift  down  the
denominator by at least this amount.

denom2		      The  smallover  command  will shift down
the denominator by at least this amount.

sup1		      Normally superscripts will be shifted up
by at least this amount.

sup2		      Superscripts  within   superscripts   or
upper  limits or numerators of smallover
fractions will be shifted up by at least
this  amount.  This is usually less than
sup1.

sup3		      Superscripts  within   denominators   or
square roots or subscripts or lower limits
will be shifted up by at least  this
amount.  This is usually less than sup2.

sub1		      Subscripts will normally be shifted down
by at least this amount.

sub2		      When  there  is  both  a subscript and a
superscript,  the  subscript   will   be
shifted down by at least this amount.

sup_drop		      The baseline of a superscript will be no
more than this much amount below the top
of  the  object on which the superscript
is set.

sub_drop		      The baseline of a subscript will	be  at
least  this much below the bottom of the
object on which the subscript is set.

big_op_spacing1	      The baseline of an upper limit  will  be
at  least this much above the top of the
object on which the limit is set.

big_op_spacing2	      The baseline of a lower limit will be at
least  this much below the bottom of the
object on which the limit is set.

big_op_spacing3	      The bottom of an upper limit will be  at
least  this  much  above	the top of the
object on which the limit is set.

big_op_spacing4	      The top of a  lower  limit  will	be  at
least  this much below the bottom of the
object on which the limit is set.

big_op_spacing5	      This much vertical space will  be  added
above and below limits.

baseline_sep	      The  baselines  of the rows in a pile or
matrix will normally be this far	apart.
In  most	cases  this should be equal to
the sum of num1 and denom1.

shift_down	      The midpoint between  the  top  baseline
and  the	bottom baseline in a matrix or
pile will be shifted down by  this  much
from  the  axis.	 In  most  cases  this
should be equal to axis_height.

column_sep	      This much space will  be	added  between
columns in a matrix.

matrix_side_sep	      This  much  space  will be added at each
side of a matrix.

draw_lines	      If this is non-zero, lines will be drawn
using  the  \D  escape  sequence, rather
than with the \l escape sequence and the
\(ru character.

body_height	      The  amount  by  which the height of the
equation exceeds this will be  added  as
extra  space  before the line containing
the equation (using  \x.)   The  default
value is 85.

body_depth	      The  amount  by  which  the depth of the
equation exceeds this will be  added  as
extra  space  after  the line containing
the equation (using  \x.)   The  default
value is 35.

nroff		      If  this	is non-zero, then ndefine will
behave like define and tdefine  will  be
ignored,	otherwise  tdefine will behave
like define and ndefine will be ignored.
The  default  value  is 0 (This is typically
changed to 1 by the eqnrc file for
the  ascii,  latin1,  utf8,  and	cp1047
devices.)

A more precise description of the role of many of these  parameters
can be found in Appendix H of The TeXbook.

Macros    [Toc]    [Back]
Macros  can  take  arguments.  In a macro body, \$n where n is between 1
and 9, will be replaced by the n-th argument if	the  macro  is	called
with  arguments;  if  there  are  fewer	than  n  arguments, it will be
replaced by nothing.  A word containing a left  parenthesis  where  the
part of the word before the left parenthesis has been defined using the
define command will be recognized as a macro call with arguments; characters
following the left parenthesis up to a matching right parenthesis
will be treated as comma-separated arguments; commas inside	nested
parentheses do not terminate an argument.

sdefine name X anything X
This is like the define command, but name will not be recognized
if called with arguments.

include "file"
Include the contents of file.  Lines of file beginning with  .EQ
or .EN will be ignored.

ifdef name X anything X
If  name	has  been defined by define (or has been automatically
defined because name is the  output  device)  process  anything;
otherwise ignore anything.  X can be any character not appearing
in anything.

Fonts    [Toc]    [Back]
eqn normally uses at least two fonts to set an equation: an italic font
for  letters, and a roman font for everything else.  The existing gfont
command changes the font that is used as the italic font.   By  default
this  is  I.   The  font  that is used as the roman font can be changed
using the new grfont command.

grfont f
Set the roman font to f.

The italic primitive uses the current italic font  set  by  gfont;  the
roman  primitive  uses  the current roman font set by grfont.  There is
also a new gbfont command, which changes the  font  used  by  the  bold
primitive.   If	you  only use the roman, italic and bold primitives to
changes fonts within an equation, you can change all the fonts used  by
your equations just by using gfont, grfont and gbfont commands.

You  can control which characters are treated as letters (and therefore
set in italics) by using the chartype command described above.  A  type
of  letter  will cause a character to be set in italic type.  A type of
digit will cause a character to be set in roman type.


### FILES[Toc][Back]

       /usr/share/tmac/eqnrc  Initialization file.


### BUGS[Toc][Back]

       Inline equations will be set at the point size that is current  at  the
beginning of the input line.


       groff(1), troff(1), groff_font(5), The TeXbook
`