[NTG-context] Myway on using mathalign

[Aditya Mahajan]

On Wed, 5 Apr 2006, WN wrote:
> One thing I want to do with a set of subformula's is
> to reference the main formula but still subnumbering the equations
> like

Try this. Warning: I do not know everything that is happening here. 
There may be some unexpected side effects.

\unprotect
\def\placesubformulawithnumber{%
   \dodoubleempty\doplacesubformulawithnumber}

\def\doplacesubformulawithnumber[#1][#2]%#2 gobbles spaces
   {\iffirstargument
     \incrementnumber[\v!formula]
     \makesectionnumber[\v!formula]
     \rawreference{\s!for}{#1}{\composedsectionnumber}
   \else
     \incrementnumber[\v!formula]
   \fi\placesubformula}
\protect


> \starttext
%% > \incrementnumber[formula]
%% > \placesubformula
\placesubformulawithnumber[eqn1] %I need to think of a smaller name
> \startformula
> \startalign
> \NC div  \vec{E} \NC =  \epsilon_{0}^{-1} \rho  \NR[eqn1:A][a]
> \NC rot  \vec{E} \NC =  0 \NR
> \NC div  \vec{B} \NC =  0 \NR[eqn1:B][b]
> \NC rot  \vec{B} \NC =  \mu_{0} \vec{j} \NR
> \stopalign
> \stopformula
> See *\in[eqn1] *for the static Maxwell equations, where we are going to 
> examine \in[eqn1:A] a bit further ....
> \stoptext
>

Also, note that div and rot should be in text font. You should 
probably do
\startmathcollection[default]
   \definemathcommand [div]      [nolop] {\mfunction{div}}
   \definemathcommand [rot]      [nolop] {\mfunction{rot}}
\stopmathcollection

and use \div \rot etc.

HTH,
Aditya


-- 
Aditya Mahajan, EECS Systems, University of Michigan
http://www.eecs.umich.edu/~adityam || Ph: 7342624008