eqn: eqn: equations in knitroff documents
In knitroff: Dynamic Reports in 'troff' with 'knitr'
eqn R Documentation
eqn: equations in knitroff documents
Description
eqn, by Brian Kernighan and Lorinda Cherry, is the troff preprocessor for mathematics; its input reads much as the formula is spoken: x sup 2 over 2. render_roff runs it for PDF and PostScript output. This page follows eqn(1) for groff 1.24.1.
Displays and inline equations
.EQ ... .ENa displayed equation, centred by ms; .EQ L left-aligns it, .EQ I indents it, and a second argument is a label at the right margin, as in .EQ C (1).
delim $$inside an .EQ ... .EN, makes $ delimit equations within the text: the mean $x bar$ is. delim off stops it.
- knitroff
in the "utf8" draft, displayed equations appear as their eqn source, because groff cannot set them on a terminal; inline equations appear between their delimiters.
Writing equations
eqn reads words separated by spaces; spaces themselves do not show. Braces group: e sup {i pi}. Quoted text is set as it is, in roman: "for all". ~ is a space and ^ half a space. eqn sets letters in italic and digits, operators and function names such as sin in roman, and turns + - = <= >= into their mathematical characters.
x sub i, x sup 2 subscript, superscript; x sub i sup 2 both
a over b a fraction
sqrt x square root
sum from i=1 to n x sub i limits under and over sum, prod, int, lim, union, inter
left ( a over b right ) brackets that grow to fit: ( [ { | and their mates, and left floor, ceiling
x bar, x under, x hat, x dot, x vec marks over or under x; also dotdot, tilde, dyad
pile { a above b above c } a vertical stack; lpile, cpile, rpile align it
matrix { ccol { a above b } ccol { c above d } } a matrix of columns; lcol, rcol align them
mark, lineup align successive equations at a point, such as their = signs
roman, italic, bold, fat the face of the next item; fat overstrikes to embolden
size 12 x, size +2 x type size of the next item
up n, down n, fwd n, back n move by n hundredths of an em
define name "text" a macro: define var "x sub i"; ndefine and tdefine only for nroff or troff
gsize n, gfont f the global type size and italic font of equations
Names eqn knows
Greek letters: alpha beta gamma delta epsilon zeta eta theta iota kappa lambda mu nu xi omicron pi rho sigma tau upsilon phi chi psi omega; spelled with a capital (Gamma) or in capitals (GAMMA) for uppercase.
Symbols and functions: inf partial grad del prime approx times nothing ... half, == != += -> <- << >>, and sin cos tan sinh cosh tanh arc exp log ln lim max min det Re Im and for if.
Added by GNU eqn: cdot cdots ldots utilde dollar, and the primitives accent uaccent big smallover vcenter split nosplit opprime type chartype set reset grfont gifont gbfont.
See Also
ms, troff, tbl. In a terminal: man eqn; and B. W. Kernighan and L. L. Cherry, A System for Typesetting Mathematics, Communications of the ACM 18 (1975), and their Typesetting Mathematics, User's Guide.
Examples
eq <- c(".EQ", "s sup 2 ~=~ 1 over {n - 1} sum from i=1 to n ( x sub i - x bar ) sup 2", ".EN")
cat(eq, sep = "\n")
knitroff documentation built on Oct. 16, 2026, 5:09 p.m.
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| eqn | R Documentation |
eqn: equations in knitroff documents
Description
eqn, by Brian Kernighan and Lorinda Cherry, is the troff preprocessor for mathematics; its input reads much as the formula is spoken: x sup 2 over 2. render_roff runs it for PDF and PostScript output. This page follows eqn(1) for groff 1.24.1.
Displays and inline equations
.EQ....ENa displayed equation, centred by ms;
.EQ Lleft-aligns it,.EQ Iindents it, and a second argument is a label at the right margin, as in.EQ C (1).delim $$inside an
.EQ....EN, makes$delimit equations within the text:the mean $x bar$ is.delim offstops it.- knitroff
in the
"utf8"draft, displayed equations appear as their eqn source, because groff cannot set them on a terminal; inline equations appear between their delimiters.
Writing equations
eqn reads words separated by spaces; spaces themselves do not show. Braces group: e sup {i pi}. Quoted text is set as it is, in roman: "for all". ~ is a space and ^ half a space. eqn sets letters in italic and digits, operators and function names such as sin in roman, and turns + - = <= >= into their mathematical characters.
x sub i, x sup 2 | subscript, superscript; x sub i sup 2 both |
a over b | a fraction |
sqrt x | square root |
sum from i=1 to n x sub i | limits under and over sum, prod, int, lim, union, inter |
left ( a over b right ) | brackets that grow to fit: ( [ { | and their mates, and left floor, ceiling |
x bar, x under, x hat, x dot, x vec | marks over or under x; also dotdot, tilde, dyad |
pile { a above b above c } | a vertical stack; lpile, cpile, rpile align it |
matrix { ccol { a above b } ccol { c above d } } | a matrix of columns; lcol, rcol align them |
mark, lineup | align successive equations at a point, such as their = signs |
roman, italic, bold, fat | the face of the next item; fat overstrikes to embolden |
size 12 x, size +2 x | type size of the next item |
up n, down n, fwd n, back n | move by n hundredths of an em |
define name "text" | a macro: define var "x sub i"; ndefine and tdefine only for nroff or troff |
gsize n, gfont f | the global type size and italic font of equations |
Names eqn knows
Greek letters: alpha beta gamma delta epsilon zeta eta theta iota kappa lambda mu nu xi omicron pi rho sigma tau upsilon phi chi psi omega; spelled with a capital (Gamma) or in capitals (GAMMA) for uppercase.
Symbols and functions: inf partial grad del prime approx times nothing ... half, == != += -> <- << >>, and sin cos tan sinh cosh tanh arc exp log ln lim max min det Re Im and for if.
Added by GNU eqn: cdot cdots ldots utilde dollar, and the primitives accent uaccent big smallover vcenter split nosplit opprime type chartype set reset grfont gifont gbfont.
See Also
ms, troff, tbl. In a terminal: man eqn; and B. W. Kernighan and L. L. Cherry, A System for Typesetting Mathematics, Communications of the ACM 18 (1975), and their Typesetting Mathematics, User's Guide.
Examples
eq <- c(".EQ", "s sup 2 ~=~ 1 over {n - 1} sum from i=1 to n ( x sub i - x bar ) sup 2", ".EN")
cat(eq, sep = "\n")
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