CAVS / Capabilities / Materials Modeling / ICME / Code Repository / WARP Code

Integrated Computational Materials Engineering (ICME)

Code: WARP

Name Atomistic Stress Simulator (WARP)
Status production version available
Release Date 2001
Authors Steve Plimpton (Sandia National Laboratory)
Contact Steve Plimpton (Sandia National Laboratory), Michael Baskes (UC San Diego), at CAVS: Bohumir Jelinek, Amitava Moitra
License © Sandia National Laboratory
Repository The code is distributed by its authors. (CAVS users: see the CAVS intranet).
Documentation WARP Overwiew.pdf
Known problems None

Description: WARP is a parallel molecular dynamics simulation code for modeling stress and strain in materials using embedded atom method (EAM) and Lennard-Jones (LJ) potentials. It is written in F90 and performs message-passing via MPI calls. This code is copyrighted property of Sandia National Laboratories. Please contact the author(s) for a copy of the source code or further information.

To report bugs, problems or to make comments please use the discussion tab above.

Compiling WARP

Type make to see a list of supported machines. You can add a new machine to the list by creating an appopriate Makefile.machine file and adding the new machine to the target list in Makefile. The "serial" target does not require MPI be installed on your workstation. The other targets require MPI.

If the -DCRACK compiler flag is set in Makefile.machine, Warp adds the command "no neighbor" that enables crack propagation simulations.

Running WARP

Warp is run by redirecting an input script to stdin, e.g.

warp_machine < in.file mpirun -np 16 warp_machine < in.file

The Structure of the WARP Input File

The input script consists of a series of single-line commands. Most of the input commands take one or more parameters. The keyword for each command should begin in the leftmost column and all characters in the command should be in lower-case. Parameters can be separated by arbitrary numbers of spaces and/or tabs (so long as the command fits on one line).

The order of commands for performing a simulation are as follows:

(1) set parameters			   only those different than defaults
(2) create box				   mandatory

Either:
  (3) orient and origin                    as needed
  (4) select region			   mandatory
  (5) define cutout			   as needed
  (6) create atoms			   mandatory (loop on 3-6 as desired)
  (7) check for atom overlap		   as needed
  (8) select and create types and eltypes  as needed
  (9) select and create vels		   as needed
Or:
  (3) scale read                           as needed
  (4) type translate                       as needed
  (5) read atoms			   mandatory
  (6) check for atom overlap		   as needed
  (7) select and create types and eltypes  as needed
  (8) select and create vels		   as needed
Or:
  (3) read restart                         mandatory

(10) select and create fixes		   as needed
(11) apply temp and pres controls	   as needed

(12) run				   can perform multiple times,
					      changing parameters as desired
Or:
(13) relax				   minimize potential energy

Note that several parameters must be defined (if not default) before the global simulation box is created and memory is allocated in step (2). These settings include units, extra memory, potential, neighbor, processor grid, periodicity, and lattice.

Please refer to WARP Overwiew.pdf for a complete list of valid Warp inputs and the "type" of parameters that should be used.

Example Input Files

in.ni100

Summary: Minimize potential energy to compute energy of [100] surface of nickel

Features demonstrated:

  • EAM potential
  • read atoms (from file snap.ni100)
  • relax

View the input file

in.shear.fixed

Summary: Shear block of atoms

Features demonstrated:

  • EAM potential
  • create atoms
  • create vels, ramp
  • create fixes, xyz
  • temp control
  • temp adjust, xyz
  • snapshot
  • snap column
  • snap thresh

View the input file

in.sic_liquid

Summary: Amorphous Si-C system

Features demonstrated:

  • MEAM potential (with multiple atom types)
  • snapshot
  • read atoms (from file snap.sic_liquid)

View the input file

in.tensile_meam

Summary: Void growth under uniaxial tensile strain

Features demonstrated:

  • MEAM potential
  • define cutout
  • create atoms
  • create fixes, xyz
  • create vels, thermal
  • create vels, ramp
  • temp control
  • temp adjust, ramp
  • restart
  • snapshot
  • snap column
  • snap thresh
  • diagnostic (tensile_meam)

View the input file

in.torsion

View the input file