Breaking an array of equations

Question

I wanted to break long equations in an array environment. To do this, I used dmath environment from breqn package but it did not work. How can I write long equations in an array environment with line breaks? My attempt is as follows:

\documentclass[11pt,twocolumn]{article}
\usepackage{amsmath}
\usepackage{breqn}
\begin{document}
\begin{dmath*}
  L_{\lambda}(\phi, \omega) =
  \left\lbrace
      \begin{array}{ll}
        a \times b \times c \times d \times e \times f \times g \times h \times i \times j \times k \times l \condition[]{for $\phi$ even}, \\
        a \times b \times c \times d \times e \times f \times g \times h \times i \times j \times k \times l \condition[]{for $\phi$ odd},
      \end{array}
  \right.
\end{dmath*}
\end{document} 

EDIT: Actual Equation :

I thought the solution will be general so posted a nicer version of the problem earlier. Following is the actual equation I want to typeset. How can I typeset this equation nicely even with manual line breaks?

\begin{dmath*}
  L_{\lambda}(\phi, \omega) =
  \left\lbrace
      \begin{array}{ll}
        2 \cos
        \left[
          \tanh \left(
            \frac{L_{\lambda-1}(\psi, \omega)}{2}
              \right) \times \tanh \left(
            \frac{L_{\lambda-1}(\psi, \omega+1)}{2}
              \right)
        \right] \condition[]{for $\phi$ even},
        \\
        2 \sin
        \left[
          \tanh \left(
            \frac{B_{\lambda-1}(\psi, \omega+1)}{2}
              \right) \times \tanh \left(
            \frac{L_{\lambda-1}(\psi, \omega)}{2}
              \right)
        \right] \condition[]{for $\phi$ odd},
      \end{array}
  \right.
\end{dmath*}

Answer 1

As David Carlisle has already pointed out in a comment, you can't have a line break inside an array environment (at least not in a column of type l). The only possible break point in the equation you describe is right after the L_{\lambda}(\phi, \omega) part.

If the equation you've posted is really what you need to typeset -- I somehow doubt it, but that is what you've posted... -- your best bet may be to (i) replace all \times symbols with \cdot symbols and (ii) reduce the font size by 1 pt (by issuing the instruction \small) for the equation in question. (Note that I've also gotten rid of the array stuff in favor of a cases* environment.)

\documentclass[11pt,twocolumn]{article}
\usepackage{mathtools,breqn} 
\usepackage{mathtools,breqn}
  \def\filler{Nam dui ligula, fringilla a, euismod sodales, 
  sollicitudin vel, wisi. Morbi auctor lorem non justo.
  Nam lacus libero, pretium at, lobortis vitae, ultricies 
  et, tellus.}
\begin{document} 
{\small
\begin{dmath*}
L_{\lambda}(\phi, \omega) =
\begin{cases*}
a\cdot b\cdot c\cdot d\cdot e\cdot f\cdot g\cdot h\cdot i\cdot j\cdot 
   k\cdot l & for $\phi$ even, \\
a\cdot b\cdot c\cdot d\cdot e\cdot f\cdot g\cdot h\cdot i\cdot j\cdot 
   k\cdot l & for $\phi$ odd.
\end{cases*}
\end{dmath*}
} % end of scope of \small statement
\filler % filler text, to show width of text column
\end{document} 

However, it would seem to be the case that you would rather have the line break (or breaks) occur somewhere to the right of the big curly brace. Here's a suggested solution which uses the split environment:

\documentclass[11pt,twocolumn]{article}
\usepackage{mathtools}
\def\filler{Nam dui ligula, fringilla a, euismod sodales, 
  sollicitudin vel, wisi. Morbi auctor lorem non justo.
  Nam lacus libero, pretium at, lobortis vitae, ultricies 
  et, tellus.}

\begin{document}
\begin{equation*}
   L_{\lambda}(\phi, \omega) =
   \begin{dcases}
      \begin{split}
         a\cdot b\cdot c\cdot d\cdot e\cdot f\cdot g \\
         {}\cdot h\cdot i\cdot j\cdot k\cdot l 
      \end{split}
      & \text{for $\phi$ even,} \\
      \begin{split}
         a\cdot b\cdot c\cdot d\cdot e\cdot f\cdot g \\
         {}\cdot h\cdot i\cdot j\cdot k\cdot l 
      \end{split}
      & \text{for $\phi$ odd.}
   \end{dcases}
\end{equation*}

\noindent\filler
\end{document} 

---

Addendum: I just noticed that you posted the actual math expression you're trying to typeset. Here's how I would try to get the job done: building on the two previous examples, I'd allow a line break both after L_{\lambda}(\phi, \omega) -- fully automatic, courtesy of breqn and the dmath* environment -- and within each of the longish expressions to the right of the large curly brace. I would also use explicit \biggl and \biggr sizing instructions for the "fences" -- and not use \left and \right.

\documentclass[11pt,twocolumn]{article}
\usepackage{mathtools,breqn}
\def\filler{Nam dui ligula, fringilla a, euismod 
sodales, sollicitudin vel, wisi. Morbi auctor lorem 
non justo. Nam lacus libero, pretium at, lobortis 
vitae, ultricies et, tellus.}
\begin{document}    
\begin{dmath*}
   L_{\lambda}(\phi, \omega) =
   \begin{dcases}
   \begin{aligned}[b]
   2 \cos \biggl[ \tanh\biggl(\frac{L_{\lambda-1}
        (\psi, \omega)}{2}\biggr) \ \ \ \ \ \\ 
        % need to "shove" the first line to the left
     \times \tanh\biggl(\frac{L_{\lambda-1}
        (\psi, \omega+1)}{2}\biggr) \biggr]
   \end{aligned} 
   & \text{for $\phi$ even,}\\
   \begin{aligned}[b]
   2 \sin\biggl[ \tanh\biggl( \frac{B_{\lambda-1}
        (\psi, \omega+1)}{2} \biggr) \\
     \times \tanh\biggl( \frac{L_{\lambda-1}
        (\psi, \omega)}{2} \biggr) \biggr]
   \end{aligned}
   & \text{for $\phi$ odd.}
   \end{dcases}
\end{dmath*}
\filler %% filler text (show width of text block)
\end{document}