Re: [O] latex equations and $ sign

[Federico Beffa]

Hi Ramus,

yes, the reason is that, differently from $...$ and \(...\), an equation environment produces a *numbered* equation to which you can add a label and reference the equation by (label) name in other parts of the text. This is not possibly with unnumbered math environments ($$, ...).

Regards,

Fede

On Fri, Jun 6, 2014 at 5:00 PM, Rasmus <address@hidden> wrote:

Federico Beffa <address@hidden> writes:

> Hi,
>
> I would like to have a mathematical equation typeset in latex and
> automatically generated by sympy, embedded in an equation environment:
>
>   #+NAME: mass-energy
>   #+BEGIN_SRC python :results raw :exports results :wrap EQUATION
>     import sympy as sp
>     E, m, c = sp.symbols('E, m, c', real=True, positive=True)
>     E = m*c**2
>     return sp.latex(E)
>   #+END_SRC
>
>
>   #+NAME: eq:1
>   #+RESULTS: mass-energy
>   #+BEGIN_EQUATION
>   c^{2} m
>   #+END_EQUATION
>
> The problem I'm facing is that despite the fact that the equation is
> already in a mathematical mode latex environment, it still gets sub- and
> superscripts surrounded by a $ sign. Here is the generated latex snippet:
>
> \begin{equation}
> \label{eq:1}
> c$^{\text{2}}$ m
> \end{equation}
>
> Is there a way to teach org-mode not to insert $ signs in equation
> environments?

Is there a reason you are not using a mode argument like this:

    #+NAME: mass-energy
    #+BEGIN_SRC python :results raw :exports results :post

      import sympy as sp
      E, m, c = sp.symbols('E, m, c', real=True, positive=True)
      E = m*c**2

      return sp.latex(E, mode="inline")
    #+END_SRC

    #+RESULTS: mass-energy
    $c^{2} m$


Alternatively, if you need to combine stuff you could use the post
argument

    #+name: wrapper
    #+BEGIN_SRC emacs-lisp :var x=""
    (format "\\(%s\\)" x)
    #+END_SRC

    #+NAME: mass-energy
    #+BEGIN_SRC python :results raw :exports results :post wrapper(x=*this*)

      import sympy as sp
      E, m, c = sp.symbols('E, m, c', real=True, positive=True)
      E = m*c**2
      return sp.latex(E)
    #+END_SRC

    #+RESULTS: mass-energy
    \(c^{2} m\)

—Rasmus

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