The PSI3 Source Code

The subversion control system (SVN) ( subversion.tigris.org) provides a convenient means by which programmers may obtain the latest (or any previous) version of the PSI3 source from the main repository or a branch version, add new code to the source tree or modify existing PSI3 modules, and then make changes and additions available to other programmers by checking the modifications back into the main repository. SVN also provides a ``safety net'' in that any erroneous modifications to the code may be easily removed once they have been identified. This section describes how to use SVN to access and modify the PSI3 source code. (Note that compilation and installation instructions are given in a separate document.)

The main repository for the PSI3 Source code is currently maintained by the Crawford group at Virginia Tech. To check out the code, one must first obtain an SVN account by emailing crawdad@vt.edu. After you have a login-id and password, you are now ready to access the repository via a secure, SSL-based WebDAV connection, but first you must decide which version of the code you need.

The PSI3 SVN repository contains three top-level directories:

• trunk: The main development area.
• branches: Release branches and private development branches are stored here.
• tags: Snapshots of the repository corresponding to public releases are stored here and should never be modified.

If you have a PSI3 SVN account, you can peruse these directories if you like by pointing web browser to:

https://sirius.chem.vt.edu/svn/psi3/