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% PSI Programmer's Manual
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% Other PSI C Libraries
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% David Sherrill, 1 February 1996
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There are several other PSI C libraries besides the previously-mentioned
\library{libipv1.a}, \library{libpsio.a}, and \library{libciomr.a}:
\begin{description}
\item\library{libchkpt.a} This library provides many routines for reading 
from and writing to the ``checkpoint'' file, \FILE{32}.  There is
generally a different function associated with each quantity in \FILE{32}
(such as the SCF energy, nuclear repulsion energy, geometry,
basis set information, etc).  This library uses the \library{libpsio.a}
library to do its input and output.  It replaces an older library 
\library{libfile30.a} which served the same purpose but which used the
old I/O from \library{libciomr.a}.
\item\library{libiwl.a} The new format for storing two-electron integrals is
IWL, or ``integrals with labels.''  The library \library{libiwl.a} provides functions for
reading and writing files in the IWL format.  The code was written with 
the goal that it could be easily modified to allow for more than 256
basis functions. Its current limit is 32768 basis functions.
\item\library{libqt.a} This is the ``Quantum Trio'' library, which contains a number
of very experimental functions or functions which don't otherwise
fit anywhere else.
\end{description}

In this section we will consider these libraries in greater detail.

\subsection{The Checkpoint File Library}\label{C_CHECKPOINT}
\input{checkpointfile}

\subsection{The Integrals-With-Labels Library}\label{C_IWL}
\input{iwl}

\subsection{The ``Quantum Trio'' Library}\label{C_QT}
\input{qt}
