LaTeX array equivalence with multiline \lbrace

LaTeX array equivalence with multiline \lbrace

[Renaud AUBIN]

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Hi all,

With LaTeX, I have
$$
\left\lbrace
  \begin{array}{l}
    \dot{q}_i = 1 \quad\text{ if } i=k \\
    \dot{q}_i = 0 \quad\text{ else}
  \end{array}
\right
$$

How to do this within a  ConTeXt document ?



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Re: LaTeX array equivalence with multiline \lbrace

[Aditya Mahajan]

<--- On Jan 24, Renaud AUBIN wrote --->

> With LaTeX, I have
> $$
> \left\lbrace
> \begin{array}{l}
>   \dot{q}_i = 1 \quad\text{ if } i=k \\
>   \dot{q}_i = 0 \quad\text{ else}
> \end{array}
> \right
> $$

Well the ConTeXt way (rather the TeX way) of doing this is to use 
\cases.

$$
  \cases{
   \dot q_i = 1, & \text{ if } i = k \cr
   \dot q_i = 0, & \text{ else } \cr
  }
$$




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

Re: LaTeX array equivalence with multiline \lbrace

[Hans Hagen]

Aditya Mahajan wrote:

><--- On Jan 24, Renaud AUBIN wrote --->
>
>  
>
>>With LaTeX, I have
>>$$
>>\left\lbrace
>>\begin{array}{l}
>>  \dot{q}_i = 1 \quad\text{ if } i=k \\
>>  \dot{q}_i = 0 \quad\text{ else}
>>\end{array}
>>\right
>>$$
>>    
>>
>
>Well the ConTeXt way (rather the TeX way) of doing this is to use 
>\cases.
>
>$$
>  \cases{
>   \dot q_i = 1, & \text{ if } i = k \cr
>   \dot q_i = 0, & \text{ else } \cr
>  }
>$$
>  
>
maybe we should add a left|right option to the new align mechanism so that one can define such constructs .. does that make sense? 

Hans 


-----------------------------------------------------------------
                                          Hans Hagen | PRAGMA ADE
              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                             | www.pragma-pod.nl
-----------------------------------------------------------------

Re: LaTeX array equivalence with multiline \lbrace

[Renaud AUBIN]

>maybe we should add a left|right option to the new align mechanism so that one can define such constructs .. does that make sense? 
>
>Hans 
>  
>
It sounds good to me...

Renaud

Re: LaTeX array equivalence with multiline \lbrace

[Aditya Mahajan]

On Wed, 25 Jan 2006, Hans Hagen wrote:

> Aditya Mahajan wrote:
>
>> <--- On Jan 24, Renaud AUBIN wrote --->
>>
>>
>>
>>> With LaTeX, I have
>>> $$
>>> \left\lbrace
>>> \begin{array}{l}
>>>  \dot{q}_i = 1 \quad\text{ if } i=k \\
>>>  \dot{q}_i = 0 \quad\text{ else}
>>> \end{array}
>>> \right
>>> $$
>>>
>>>
>>
>> Well the ConTeXt way (rather the TeX way) of doing this is to use
>> \cases.
>>
>> $$
>>  \cases{
>>   \dot q_i = 1, & \text{ if } i = k \cr
>>   \dot q_i = 0, & \text{ else } \cr
>>  }
>> $$
>>
>>
> maybe we should add a left|right option to the new align mechanism so 
> that one can define such constructs .. does that make sense?

If I understand you correctly, then something like this

\definealign[cases][left={\left\{}, right={\right.}, n=2, 
align={left,left}]

will give us \startcases, \stopcases which works like \cases. Such a 
feature will be very useful.


Is it possible to define left|right in such a way that
\definealign[important][left={\framed\bgroup},right={\egroup}]
results in a frame around the equations (and does not include the equation 
numbers), that is the frame is as broad as the width of the largest 
equation that follows. This mechanism can be used to highlight equations.

Also, in another post, I had asked if it is possible to have cases that 
are numbered, that is, can I get

     { b , if whatever     (1a)
  a ={
     { c,  otherwise       (1b)

This is not important, but will be nice to have.

Aditya

Re: LaTeX array equivalence with multiline \lbrace

[Renaud AUBIN]

I've read the post [NTG-context] Math Cases and I'm interested to have 
the possibility to do this kind of numbering:

 { b , if whatever     (1a)
  a ={
     { c,  otherwise       (1b)



Aditya Mahajan a écrit :

>If I understand you correctly, then something like this
>
>\definealign[cases][left={\left\{}, right={\right.}, n=2, 
>align={left,left}]
>
>will give us \startcases, \stopcases which works like \cases. Such a 
>feature will be very useful.
>
>
>Is it possible to define left|right in such a way that
>\definealign[important][left={\framed\bgroup},right={\egroup}]
>results in a frame around the equations (and does not include the equation 
>numbers), that is the frame is as broad as the width of the largest 
>equation that follows. This mechanism can be used to highlight equations.
>
>Also, in another post, I had asked if it is possible to have cases that 
>are numbered, that is, can I get
>
>     { b , if whatever     (1a)
>  a ={
>     { c,  otherwise       (1b)
>
>This is not important, but will be nice to have.
>
>Aditya
>_______________________________________________
>ntg-context mailing list
>ntg-context@ntg.nl
>http://www.ntg.nl/mailman/listinfo/ntg-context
>  
>

Re: LaTeX array equivalence with multiline \lbrace

[Hans Hagen]

Renaud AUBIN wrote:

>I've read the post [NTG-context] Math Cases and I'm interested to have 
>the possibility to do this kind of numbering:
>
> { b , if whatever     (1a)
>  a ={
>     { c,  otherwise       (1b)
>
>  
>
>>If I understand you correctly, then something like this
>>
>>\definealign[cases][left={\left\{}, right={\right.}, n=2, 
>>align={left,left}]
>>
>>will give us \startcases, \stopcases which works like \cases. Such a 
>>feature will be very useful.
>>
>>
>>Is it possible to define left|right in such a way that
>>\definealign[important][left={\framed\bgroup},right={\egroup}]
>>results in a frame around the equations (and does not include the equation 
>>numbers), that is the frame is as broad as the width of the largest 
>>equation that follows. This mechanism can be used to highlight equations.
>>
>>Also, in another post, I had asked if it is possible to have cases that 
>>are numbered, that is, can I get
>>
>>    { b , if whatever     (1a)
>> a ={
>>    { c,  otherwise       (1b)
>>
>>This is not important, but will be nice to have.
>>    
>>
something like this? 

\unprotect 

\definesystemvariable{ce}
\def\v!mathcases     {mathcases}
\def\c!numberdistance{numberdistance}

\def\setupmathcases
  {\dodoubleempty\dosetupmathcases}

\def\dosetupmathcases[#1][#2]%
  {\ifsecondargument
     \getparameters[\??ce#1][#2]%
   \else
     \getparameters[\??ce][#1]%
   \fi}

\let\currentmathcases\empty

\def\mathcasesparameter#1%
  {\executeifdefined{\??ce\currentmathcases#1}{\executeifdefined{\??ce#1}\empty}}

\setupmathcases
  [\c!distance=1em,
   \c!numberdistance=2.5em]

\def\definemathcases
  {\dodoubleempty\dodefinemathcases}

\def\dodefinemathcases[#1]% [#2]%
  {\setvalue{\e!start#1}{\dodoubleempty\dostartmathcases[#1]}%
   \setvalue{\e!stop #1}{\dostopmathcases}%
   \setupmathcases[#1]}% [#2]

\definemathcases[cases]
\definemathcases[\v!mathcases]

\def\dodocasesNC
  {\gdef\docasesNC{\endmath&}}

\let\docasesNR\doalignNR

\def\dostartmathcases[#1][#2]%
  {\begingroup
   \edef\currentmathcases{#1}%
   \doifassignmentelse{#2}{\setupmathcases[#1][#2]}\donothing
   \left\{%
   \,%
   \vcenter\bgroup
   \pushmacro\docasesNC
   \let\endmath\relax
   \def\NC{\docasesNC}%
   \def\MC{\docasesNC\ifmmode\else$\def\endmath{$}\fi}%
   \global\let\docasesNC\dodocasesNC
   \def\NR{\endmath&\global\let\docasesNC\dodocasesNC\doxxdoubleempty\docasesNR}%
   \normalbaselines
   \mathsurround\zeropoint
   \everycr\emptytoks
   \tabskip\zeropoint
   \global\eqaligncolumn\plusone
   \halign\bgroup
        \span$##$\hfil
       &\hskip\mathcasesparameter\c!distance\relax\popmacro\docasesNC##\hfil
       &\hskip\mathcasesparameter\c!numberdistance\relax\span\textineqalign{##}%
     \crcr} % todo: number

\def\dostopmathcases
  {\crcr
   \egroup
   \popmacro\docasesNC
   \egroup
   \right.
   \endgroup}

\protect

\showframe

\placeformula \startformula \startcases
\NC 2 \NC $ y > 0 $ \NR
\NC 7 \NC $ x = 7 $ \NR[+]
\NC 4 \NC otherwise \NR
\stopcases \stopformula

\placeformula \startformula x
\startcases
\NC 2 \NC $ y > 0 $ \NR[+]
\NC 7 \NC $ x = 7 $ \NR
\NC 4 \NC otherwise \NR
\stopcases
\stopformula

\placeformula \startformula \startcases
\NC 2 \NC $ y > 0 $ \NR
\NC 7 \NC $ x = 7 $ \NR
\NC 4 \NC otherwise \NR
\stopcases \stopformula

\placeformula \startformula x
\startcases
\NC 2 \NC $ y > 0 $ \NR
\NC 7 \NC $ x = 7 $ \NR
\NC 4 \NC otherwise \NR
\stopcases
\stopformula


-----------------------------------------------------------------
                                          Hans Hagen | PRAGMA ADE
              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                             | www.pragma-pod.nl
-----------------------------------------------------------------

Re: LaTeX array equivalence with multiline \lbrace

[Renaud AUBIN]

Does not compile... I assume that I need to update math-ext. Am I right 
(before update ;-) ) ?

Re: LaTeX array equivalence with multiline \lbrace

[Aditya Mahajan]

<--- On Jan 26, Hans Hagen wrote --->
>>
>>> Also, in another post, I had asked if it is possible to have cases that
>>> are numbered, that is, can I get
>>>
>>>    { b , if whatever     (1a)
>>> a ={
>>>    { c,  otherwise       (1b)
>>>
>>> This is not important, but will be nice to have.
>>>
>>>
> something like this?
>
> [ code snipped ]

> \placeformula \startformula \startcases
> \NC 2 \NC $ y > 0 $ \NR
> \NC 7 \NC $ x = 7 $ \NR[+]
> \NC 4 \NC otherwise \NR
> \stopcases \stopformula


Not exactly. In this, I get two formula numbers, one for the case 
`x=7' and the other for the entire equation. I can remove 
\placeformula and almost get the desired behaviour. There should be an 
option to flushright the equation number corresponding to each case, 
i.e., I should be able to get

+-----------------------------------------------------+
|                                                     |
|         ,-                                          |
|         |   15,  if something                   (1) |
|     x = {                                           |
|         |   0,  otherwise                       (2) |
|         `-                                          |
+-----------------------------------------------------+


Where the frame is the page boundaries. I hope I am making sense here.

Further, I can not get correct subnumbering here. Look at the output 
of

\startformula \startcases
\NC a \NC if something \NR[eq:a][a]
\NC b \NC otherwise    \NR[eq:b][b]
\stopcases \stopformula

Other than these minor glitches, this is perfect.



Aditya

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

Re: LaTeX array equivalence with multiline \lbrace

[Hans Hagen]

Aditya Mahajan wrote:

>Not exactly. In this, I get two formula numbers, one for the case 
>`x=7' and the other for the entire equation. I can remove 
>\placeformula and almost get the desired behaviour. There should be an 
>option to flushright the equation number corresponding to each case, 
>i.e., I should be able to get
>
>+-----------------------------------------------------+
>|                                                     |
>|         ,-                                          |
>|         |   15,  if something                   (1) |
>|     x = {                                           |
>|         |   0,  otherwise                       (2) |
>|         `-                                          |
>+-----------------------------------------------------+
>
>
>Where the frame is the page boundaries. I hope I am making sense here.
>  
>
this is not easy since the "x = big left brace" and "matrix" are 
independent things  and  i see no easy way to flush the matrix related 
number to the margin; i leave that to taco because he has more insight 
in what is possible in math/alignments

Hans

Re: LaTeX array equivalence with multiline \lbrace

[Taco Hoekwater]

Hans Hagen wrote:
>>+-----------------------------------------------------+
>>|                                                     |
>>|         ,-                                          |
>>|         |   15,  if something                   (1) |
>>|     x = {                                           |
>>|         |   0,  otherwise                       (2) |
>>|         `-                                          |
>>+-----------------------------------------------------+

The basic TeX structure for this would be an full-width \eqalignno,
like so:

   \def\fixeqline{\noalign{\kern-.4\baselineskip}}
   \def\guessedstrut{\vrule height 12pt depth 12pt width0pt}
    $$\eqalignno{
      &  15,  \hbox{ if something}   & (1)\cr \fixeqline
      x=\smash{\left\{\guessedstrut\right .}
      &                              &    \cr \fixeqline
      &  0, \hbox{ otherwise}        & (2)\cr} $$

Not very nice, but TeX (the engine) does not allow a cleaner
solution. I guess it is possible to wrap this up in a nicer
looking macro, but it requires some trial typesetting for the
magical quantities used in the two macros.


Cheers, Taco