Orac (MD program)

In computer software, Orac is a classical molecular dynamics program, to simulate complex molecular systems at the atomistic level. In 1989-1990, the code was written originally by Massimo Marchi during his stay at International Business Machines (IBM), Kingston (USA). In 1995, the code was developed further at the Centre européen de calcul atomique et moléculaire (CECAM). It is written in the programming language Fortran. In 1997, it was released under a GNU General Public License (GPL).^[1] The latest release ^[2] of Orac may be run in parallel using the standard Message Passing Interface (MPI) libraries, allowing replica exchange simulations, multiple walkers metadynamics^[3] simulations and multiple steered molecular dynamics^[4] nonequilibrium trajectories.