How to break this function up between multiple lines?

Question

I need to split the equation

$$f(x)=\bigg(\prod_{i=1}^n((y(\lceil\frac{i-1}{i}\rceil)+1|(\lceil\frac{i-1}{i}\rceil)-1|)
2^{(2(g(x)+(\lceil\frac{i}{3}\rceil)(\lceil\frac{(y)(2^{|y\,\bmod\,3-3|})-1}{9}\,
\bmod\,1\rceil)(\lceil\frac{i-1}{i}\rceil)+(\lceil\frac{i+2}{3}\rceil)
(|\lceil\frac{(y)(2^{|y\,\bmod\,3-3|})-1}{9}\,\bmod\,1\rceil-1|)
(\lceil\frac{i-1}{i}\rceil)+(\lceil\frac{i+1}{3}\rceil)
(|\lceil\frac{i-1}{i}\rceil-1|))+|(g(x)\,\bmod\,3)-3|)}-1)/3_i\bigg)(x)$$

between two lines maybe even three. How do I do this is TexMakerX?

Answer 1

Yikes, that's quite a function- I don't envy you!

I'd try something like

You'll notice that I've used a lot of \left(...\right), and also some \left. and \right. Essentially the main thing is to introduce a local function F

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{align*}
 f(x)&=\left(\prod_{i=1}^n\left(\left(y\left(\left\lceil\frac{i-1}{i}\right\rceil\right)+1\left|\left(\left\lceil\frac{i-1}{i}\right\rceil\right)-1\right|\right)2^{F\left(x\right)}-1\right)\frac{1}{3_i}\right)\left(x\right)
 \intertext{where}
 F(x)&= \left(2\left(g(x)+\left(\left\lceil\frac{i}{3}\right\rceil\right)\right.\right. \cdot  \left(\left\lceil\frac{\left(y\right)\left(2^{|y\,\bmod\,3-3|}\right)-1}{9}\,\bmod\,1\right\rceil\right)\left(\left\lceil\frac{i-1}{i}\right\rceil\right)\\
     &\phantom{=}+\left(\left\lceil\frac{i+2}{3}\right\rceil\right)\cdot  \left(\left|\left\lceil\frac{\left(y\right)\left(2^{|y\,\bmod\,3-3|}\right)-1}{9}\,\bmod\,1\right\rceil-1\right|\right)\left(\left\lceil\frac{i-1}{i}\right\rceil\right)\\
     &\phantom{=}+\left(\left\lceil\frac{i+1}{3}\right\rceil\right)\cdot  \left.\left(\left|\left\lceil\frac{i-1}{i}\right\rceil-1\right|\right)\right)\\
     &\phantom{=}+\left.\vphantom{\frac{1}{2}}|(g(x)\,\bmod\,3)-3|\right)
\end{align*}
\end{document}