[l2h] eqnarray/matrix bug in latex2html

[Ross Moore]

Hello Mirek,

On Wed, 1 Oct 2003, [ISO-8859-2] Mirosław Prywata wrote:

> Użytkownik Ross Moore napisał:
>
> >>I found that late2thml has problems with mirror in eqnarray environment.
> >>  It can be due to the fact, that eqnarray and matrix has the same row
> >>separator - &. The first & is treated as & from eqnarray and the rest of
> >>matrix is treated as another part of eqnaray. From this point all the
> >>equation are renumbered and displayed in unproper place and order.
> >
> >
> > Are you using  \usepackage{amsmath} ?
>
> no,
>
> > Please provide example coding which does not work for you.
>
> The example latex file is very simple:
>
> \documentclass[12pt]{article}
>
> \usepackage[polish]{babel}
> \usepackage{t1enc}
> \usepackage[latin2]{inputenc}
> \usepackage[dvips]{graphicx}
>
> \begin{document}
> \selectlanguage{polish}
>
> \begin{eqnarray}
> \sigma_x=\left( \matrix{0&1\cr 1&0}\right),
> \sigma_y=\left(\matrix{0&-i\cr i&0}\right),
> \sigma_z=\left(\matrix{1&0\cr 0&-1}\right).
> \end{eqnarray}

Ahah, you are mixing plain TeX syntax with LaTeX.
This ought to be:

\begin{eqnarray}
\sigma_x=\left( \begin{matrix}0&1\\ 1&0\end{matrix}\right)\,,\quad
\sigma_y=\left(\begin{matrix}0&-i\\ i&0\end{matrix}\right)\,,\quad
\sigma_z=\left(\begin{matrix}1&0\\ 0&-1\end{matrix}\right)\,.
\end{eqnarray}

(See the result (with  amsmath  loaded) at:
   http://www-texdev.ics.mq.edu.au/MIREK/eqntest/
)

so that LaTeX2HTML can detect the sub-environments,
and treat those separately, before parsing the {eqnarray}

But if you are using advanced mathematical structures, such
as matrices and aligned sets of equations, then you really
should be using  \usepackage{amsmath}.


This allows advanced structures to be specified in a more
intuitive manner --- rather than just trying to draw pieces
on a page, expecting the resulting visual effect to carry
the intended meaning.

In LaTeX2HTML, the results for mathematics are generally
much better when {amsmath} is loaded, than when not loaded,
because the various types of alignments give a better clue
as to what kind of layout structure should be used in the HTML,
and that images are more likely to be appropriate.

>
> \end{document}
>
> latex2html treats it strangely, first it knows there is only one
> formula, and on the other hands it tries to split the eqnarray into
> several (here 3 ??) formulae.

An {eqnarray} is designed to create 3 columns in LaTeX.
You may not always choose to use all the columns, but
LaTeX2HTML will nevertheless construct a <TABLE> with 3 cols.
because that's the purpose of an {eqnarray}.

You have the choice of using {equation} of {displaymath}
environments, if you want a single column, with/out numbering.

>
> If you ad some more formulae to this document you will see what will
> happen. Everything gets mixed.
>
> and the version of latex2html:
>
> $ latex2html --version
>   [english]This is jLaTeX2HTML Version 2002 (1.62) JA patch-1.4
> by Kenshi Muto, Debian Project.
>
> Original LaTeX2HTML Version 2002 (1.62)
> by Nikos Drakos, Computer Based Learning Unit, University of Leeds.
>

Hope this helps,

	Ross Moore

>
> Mirek
>
> Mirek
>
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