Big integral in lmodern [duplicate]

Question

Possible Duplicate:
Big integral sign

How can I get a large integral sign in the Latin Modern font? If I remove the 2nd line from the following, it works fine (printing an integral, and the same integral with enlarged integral sign). But if I leave it as is, the two integrals turn out identically. (The relsize package doesn't help either.)

\documentclass{book}
\usepackage{lmodern}
\usepackage{bigints}
\begin{document}

    \begin{align}
    \int_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
    \end{align}

    \begin{align}
    \bigints_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
    \end{align}

\end{document}

Answer 1

For dubious reasons, lmodern loads the "math extension" font only at a fixed size. You can correct this behavior by declaring it in a different way:

\documentclass{book}
\usepackage{lmodern}
\usepackage{bigints}

\DeclareFontFamily{OMX}{lmex}{}
\DeclareFontShape{OMX}{lmex}{m}{n}{<-> lmex10}{}

\begin{document}
    \begin{align}
    \int_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
    \end{align}

    \begin{align}
    \bigints_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
    \end{align}

\end{document}

I won't show the result which is awful. Please, avoid the "big integrals".

Answer 2

it does not work with the math fonts of Latin Modern, use CM math instead:

\documentclass{book}
\usepackage[T1]{fontenc}
\usepackage{bigints}
\renewcommand\familydefault{lmr}% uses lm only for text
\begin{document}
foo\textit{bar}
  \begin{align}
    \int_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
  \end{align}

  \begin{align}
        \bigint\limits_{-Y}^{Y}\left(\frac{X}{\frac{X}{\frac{X}{X}}}\right)dX
  \end{align}

\end{document}