is well-suited for working with a large document like a thesis.
For instance, the \ref{ } command makes it easy to work on a long
document without spending lots of time updating cross-references.
However, you may find it frustrating to wait as works
through your entire 150-page document just so that you can see whether
a diagram looks all right. Fortunately, there
is a way to get around this.
First of all, divide your file into smaller files containing, say, the
chapters of your thesis. We'll suppose these files are
chapter1.tex, chapter2.tex and so on. Then, create a
master file, say thesis.tex, that looks like this, for example:
\documentclass[12pt]{report}
\usepackage{amstex}
...
\newtheorem{thm}{Theorem}
\begin{document}
...
\end{document}
Obviously, you should use whatever \documentclass command is
appropriate, and put whatever \newtheorem commands you are using
before the \begin{document}.
Now when you use on the file thesis.tex, will
read in the different chapters from the files you specified. Now,
suppose you are working on Chapter 5 and haven't changed the other
chapters. Then by putting the command
\includeonly{chapter5}
between the \documentclass command and the
\begin{document} command, you can tell to re-process only
Chapter 5, and ignore the other \include
commands. However, will remember the
\label{ } commands from the other chapters, so that
all the \ref commands in Chapter 5 will be okay. Also,
will remember that the \chapter{ } command
which, presumably, appears at the beginning of the file,
should start Chapter 5, not Chapter 1.