Re: LaTeX maths with array...

[Aditya Mahajan <adityam@umich.edu>]

On Sat, 19 Apr 2008, Pau wrote:

> Hi,
>
> I am preparing an e-journal for astro and I have many articles with
> lots of equations. Unfortunately, authors are using LaTeX maths and
> this is giving me trouble.
>
> I have read and followed the steps of
>
> http://wiki.contextgarden.net/LaTeX_Math_in_ConTeXt
>
> and
>
> http://wiki.contextgarden.net/Math_with_newmat
>
> and it has helped me a lot but there's a snag I run all the time in: array
>
> Typically, the equation giving troubles is of the kind:
>
> \begin{equation}
> \begin{array}{rl}
> h & \sim \mu M^{2/3}f^{2/3}/r\\
>  & \sim M_{ch}^{5/3}f^{2/3}/r\\
> \end{array}
> \end{equation}

The correct way to translate array in ConTeXt is

\startformula
  \startmatrix[align={right,left}]
    \NC h \NC \sim \mu M^{2/3}f^{2/3}/r \NR
    \NC   \NC \sim M_{ch}^{5/3} f^{2/3}/r \NR
\stopmatrix
\stopformula

However, I think that the original input is wrong. The autor probably 
wanted to use split (or align), rather than array.


> when I try to compile, I get
>
> ! Misplaced alignment tab character &.
> l.484 h&
>        \sim \mu M^{2/3}f^{2/3}/r\\
>
> Of course, when I use
>
> \startformula\eqalign{
> h & \sim \mu M^{2/3}f^{2/3}/r   \cr
>  & \sim M_{ch}^{5/3}f^{2/3}/r  \cr
> }\stopformula
>
>
> everything runs smoothly but I cannot convert all equations containing
> a {array}{rl} or similar, because I would never end... I guess that
> writing a script to convert them in eqlign would be feasible, but it's
> a very... precarious way... I would prefer to fix the problem from
> ConTeXt itself...
>
> how??

Do you want ConTeXt to parse \begin{array}{...} ... \end{array} and 
typeset it? This is possible, but essentially involves rewritting array in 
ConTeXt, without any of the configuration options that ConTeXt provides.

The (now deprecated) amsl module provided something similar to LaTeX 
array. Have you tried using that part of the code?

Aditya
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