CHARMM:The Basics

Introduction
What is CHARMM?

CHARMM (Chemistry at HARvard Macromolecular Mechanics) is a computational package used for classical, quantum and hybrid quantum/classical simulations. CHARMM is a complex program with over 500,000 lines of code and offers many analytical features. The program employs a command line interface and in practice most interaction with the program is done via user-created input scripts.

Who developed CHARMM?

CHARMM was created by the Martin Karplus Group at Harvard but developers from across the globe are continually working to improve CHARMM and add new features. A partial list of current CHARMM developers can be found here.

What are some of the features of CHARMM?


 * Robust Langevin and molecular dynamics simulation engine
 * Extensive trajectory analysis features.
 * Much of the code is parallelized for execution on SMP machines and clusters.
 * Multiscale modeling (e.g. QM/MM simulations).
 * Interfaces to various QM packages.
 * Embedded X11 graphics subsystem.
 * Facilities for normal mode and quasiharmonic analysis.
 * For more information see CHARMM Documentation

Installation
Installation of CHARMM

CHARMM runs on a variety of UNIX-like systems, although many installations currently are being done on Linux. With a little bit of work, the program can be installed on Windows machines via the CYGWIN emulation layer.

There are many options for installing CHARMM, many of which the beginning user need not touch. It is highly recommended that the user read install.doc and/or the installation board on the CHARMM forums before trying to install CHARMM.

CHARMM must be installed through a command line. The general format is:

./install.com  [  ]

The following is a list for the different types of installation based on your preferences and computer.

Note: Compiling with the gcc 4.0 as your C compiler may result in installation problems. It is recommended that gcc 4.1 or later is used. Currently gcc 4.2 is recommended due to issues with trajectory file compatibility under gcc 4.1 (although this problem can be worked around (consult the Installation board mentioned above for details). CHARMM is being updated to Fortran 95, so gcc3, which only has a Fortran 77 compiler (g77) will not compile recent versions.