Difference between revisions of "Math"

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* [[Bold Math]]
 
* [[Bold Math]]
 
* [http://homepage.mac.com/atl/tex/EulerContext.pdf Euler in ConTeXt (using Euler math font)] by Adam Lindsay
 
* [http://homepage.mac.com/atl/tex/EulerContext.pdf Euler in ConTeXt (using Euler math font)] by Adam Lindsay
 
<context>
 
\tfa \bf This $u$ is $p$ a test.
 
</context>
 
  
 
==Science==
 
==Science==

Revision as of 07:04, 15 August 2005

< Main Page | Math with newmat | MathML >

Many people start with TeX because they want to set formulae. Simple math typesetting exists since PlainTeX and these commands work in ConTeXt as in LaTeX. Advanced math was introduced to TeX by AMS (American Mathematical Society); nowadays AMSTeX and LaTeX are united. But how can one use advanced math with ConTeXt?

  • There are two different math modules on CTAN, nath and amsl.
  • It is also possible to use most LaTeX equations in ConTeXt with a relatively small set of supporting definitions.
  • The "native" ConTeXt way of math is MathML, an application of XML - rather verbose but mighty.
  • And there's a new math module in the distribution.

Simple Math

ConTeXt supports inline math (mathematical formulas set within ordinary paragraphs as part of the text) and display math (mathematics set on lines by themselves, often with equation numbers). Inline math is enclosed in "$" signs, while display math is enclosed in a \startformula / \stopformula pair.

Inline math is set as $c^2 = a^2 + b^2$, and display math as
\placeformula
\startformula
c^2 = a^2 + b^2.
\stopformula

This, when typeset, produces the following:

The \placeformula command is optional, and produces the equation number; leaving it off produces an unnumbered equation.

ConTeXt's base mathematics support is built on the mathematics support in plain TeX, thus allowing quite complicated formulas. (There are also some additional macros, such as the \text command for text-mode notes within math.) For instance:

A more complicated equation:
\placeformula
\startformula
{{\theta_{\text{ConTeXt}}}^2 \over x+2}
 = \pmatrix{a_{11}&a_{12}&\ldots&a_{1n}\cr
            a_{21}&a_{22}&\ldots&a_{2n}\cr
            \vdots&\vdots&\ddots&\vdots\cr
            a_{n1}&a_{n2}&\ldots&a_{nn}\cr}
   \pmatrix{b_1 \cr b_2 \cr \vdots \cr b_n}
 + \sum_{j=1}^\infty z^j
   \left( \sum_{\scriptstyle n=1 \atop \scriptstyle n \ne j}^\infty Z_j^n \right)
\stopformula

which produces

Here you can try it "live" (PDF interface!).

MathAlignment is covered on a separate page.

Formula Numbering

As mentioned above, formulas can be numbered using the \placeformula command. This (and the related \placesubformula command have an optional argument which can be used to produce sub-formula numbering. For example:

Examples:
\placeformula{a}
\startformula
c^2 = a^2 + b^2
\stopformula

\placesubformula{b}
\startformula
c^2 = a^2 + b^2
\stopformula

What's going on here is simpler than it might appear at first glance. Both \placeformula and \placesubformula produce equation numbers with the optional tag added at the end; the sole difference is that the former increments the equation number first, while the latter does not (and thus can be used for the second and subsequent formulas that use the same formula number but presumably have different tags).

This is sufficient for cases where the standard ConTeXt equation numbers suffice, and where only one equation number is needed per formula. However, there are many cases where this is insufficient, and \placeformula defines \formulanumber and \subformulanumber commands, which provide hooks to allow the use of ConTeXt-managed formula numbers with plain TeX equation numbering. These, when used within a formula, simply return the formula number in properly formatted form, as can be seen in this simple example with plain TeX's \eqno. Note that the optional tag is inherited from \placeformula.

More examples:
\placeformula{c}
\startformula
\let\doplaceformulanumber\empty
c^2 = a^2 + b^2   \eqno{\formulanumber}
\stopformula

In order for this to work properly, we need to turn off ConTeXt's automatic formula number placement; thus the \let command to empty \doplaceformulanumber, which must be placed after the start of the formula. In many practical examples, however, this is not necessary; ConTeXt redefines \displaylines and \eqalignno to do this automatically.

For more control over sub-formula numbering, \formulanumber and \subformulanumber have an optional argument parallel to that of \placeformula, as demonstrated in this use of plain TeX's \eqalignno, which places multiple equation numbers within one formula.

Yet more examples:
\placeformula
\startformula
\eqalignno{c^2 &= a^2 + b^2  &\formulanumber{a} \cr
           a^2 + b^2 &= c^2  &\subformulanumber{b} \cr
           d^2 &= e^2        &\formulanumber\cr}
\stopformula

Note that both \formulanumber and \subformulanumber can be used within the same formula, and the formula number is incremented as expected. Also, if an optional argument is specified in both \placefigure and \formulanumber, the latter takes precedence.

Number Formatting

There's a special command, \digits, and a own manual about formatting numbers, see Pasting digits together

Math Fonts

Science

  • Esp. for physics there’s the units module.
  • Additions to MathML are PhysML and ChemML.
  • Chemistry
  • There's a module for chemical structure formulae: PPCHTeX (works also with LaTeX). It's based on Metapost and MetaFun.