MDI Standard

This section provides details on the commands defined by the MDI Standard.The MDI Standard defines a set of commands that can be used to control simulations and communicate data between engines.

You can also tags for the MDI Standard.

Simulation Control and Node Management

Commands that control the flow of the simulation and manage the engine’s nodes.

Command Name	Description
@	Manage operations related to the current node.
@COORDS	Go to point in code after atomic coordinates have been updated.
@DEFAULT	Operations related to the @DEFAULT node. The @DEFAULT node is the node that the engine goes to when launched.
@FORCES	Go to point in code after forces have been calculated.
@INIT_MC	Initialize a Monte Carlo simulation.
@INIT_MD	Initialize a Molecular Dynamics simulation.
@INIT_OPTG	Initialize a geometry optimization.
@PRE-FORCES	Go to point in code where forces have been partially calcualted.
EXIT	Exit the engine.

Data Exchange

Commands that exchange data between the driver and the engine.

Command Name	Description
CDENSITY	Exchange Cartesian coordinates for grid points.
CELL	Exchange cell vectors for simulation boxes.
CELL_DISPL	Exchange cell displacement vectors for simulation boxes.
CHARGES	Exchange atomic charge information.
CLATTICE	Send lattice coordinates.
COORDS	Exchange atomic coordinate information.
CPOTENTIAL	Send Cartesian coordinates of grid points.
DENSITY	Retrieve electronic density information.
DIMENSIONS	Retrieve simulation cell dimensionality (periodic or non-periodic).
ELECT_MULT	Exchange electronic multiplicity.
ELEMENTS	Exchange atomic element information.
ENERGY	Receive total energy information.
FORCES	Exchange atomic forces information.
KE	Receive total kinetic energy.
KE_ELEC	Receive electronic kinetic energy.
KE_NUC	Receive nuclear kinetic energy.
LABELS	Receive a label for each atom in the system.
LATTICE	Send lattice point charges.
LATTICE_FORCES	Receive lattice forces.
MASSES	Retrieve atom masses.
MONKHORST-PACK_NPOINTS	Send number of points for a Monkhorst-Pack grid.
MONKHORST-PACK_SHIFT	Send Monkhorst-Pack grid shift.
NATOMS	Receive number of atoms.
NDENSITY	Receive number of points for electronic density on a grid.
NLATTICE	Send number of lattice points.
NPOTENTIAL	Send the number of potential grid points.
PE	Receive total potential energy.
PE_ELEC	Receive electronic potential energy.
PE_NUC	Receive nuclear potential energy.
POTENTIAL	Send potential grid values.
SPIN_POLARIZATION	Exchange spin polarization information.
STRESS	Exchange virial stress tensor.
TOTCHARGE	Exchange total charge information
VELOCITES	Exchange atomic velocities.

Information

Commands that provide information about MDI and/or an engine.

Command Name	Description
NAME	Receive engine name.
VERSION	Receive MDI Library version.