Grid Flavor¶

In ExaStamp, the grid flavor pre-defines the data attached to particles during the simulation, meaning that such data is stored anyway along the entire trajectory. Some fields can evolve with time such as positions or velocity while some can be fixed such as the particle identifiers or partial charges.

General Concept¶

To define the grid flavor to be used in the simulation, a YAML block can be used in the input file. Below are exemples of definitions for all grid flavors available in ExaStamp.

.. code-block:: yaml

# Minimal grid_flavor: grid_flavor_minimal

# Multimat grid_flavor: grid_flavor_multimat

# Full grid_flavor: grid_flavor_full

# Mechanics grid_flavor: grid_flavor_mechanics

# Multimat Mechanics grid_flavor: grid_flavor_multimat_mechanics

# Rigid Molecules grid_flavor: grid_flavor_rigidmol

.. warning::

Depending on the grid flavor chosen by the user, some fields won't be available for output. For example if one needs the global stress tensor computed by the thermodynamic_state operator, an appropriate grid_flavor to use would be the grid_flavor_full.

Amongst these grid flavors, mutliple fields are attached to particles. The following table lists the fields common to all grid flavors

.. list-table:: Common fields to all grid flavors :widths: 30 30 :header-rows: 1 :align: center

• • Field
  • Type
• • Potential Energy
  • float
• • Position
  • Vec3d
• • Velocity
  • Vec3d
• • Force
  • Vec3d

Below is another table listing the additional per-particle fields in the different grid flavors. Depending on the application you're thinking about, you may choose the appropriate grid_flavor for your simulation.

.. list-table:: Per-particle fields available in the different grid flavors :widths: 30 30 30 30 30 30 30 :header-rows: 1 :align: center

• • Field \ Grid Flavor
  • mimimal
  • multimat
  • multimat_mechanics
  • full
  • full_mechanics
  • rigidmol
• • Filtered Position
  • NO
  • NO
  • YES
  • NO
  • YES
  • NO
• • Particle Identifier
  • NO
  • YES
  • YES
  • YES
  • YES
  • YES
• • Particle Type
  • NO
  • YES
  • YES
  • YES
  • YES
  • YES
• • Virial
  • NO
  • NO
  • YES
  • YES
  • YES
  • NO
• • Particle Charge
  • NO
  • NO
  • NO
  • YES
  • NO
  • YES
• • Molecule Identifier
  • NO
  • NO
  • NO
  • YES
  • NO
  • YES
• • Cmol
  • NO
  • NO
  • NO
  • YES
  • NO
  • YES
• • Quaternion
  • NO
  • NO
  • NO
  • NO
  • NO
  • YES
• • Angular Momentum
  • NO
  • NO
  • NO
  • NO
  • NO
  • YES
• • Torque
  • NO
  • NO
  • NO
  • NO
  • NO
  • YES

Recommendations¶

Below are some recommendations on using the different grid flavors, depending on the particle types involved in your simulation.

Mono-specy and Multi-species Atomic Systems¶

For mono-species and multi-species atomic systems, the different grid flavors that can be used are the following:

• grid_flavor_minimal to model system with minimal per-particle data. Not compatible with charged systems.
• grid_flavor_multimat to model multi-species systems and analyse the system using particle identifiers.
• grid_flavor_full to model multi-species systems with per-particle charges and virial.

Rigid Molecules Systems¶

For rigid molecules system, the only grid flavor that can be used is the grid_flavor_rigidmol.

Flexible Molecules Systems¶

For systems containing fully flexible molecules, the only grid flavor that can be used is the grid_flavor_full.